ISSN: 0950-5423 eISSN: 1365-2621 |
food and food industries
Published by John Wiley & Sons
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- Effects of catechin on the phenolic content and antioxidant properties of low‐fat cheese
The effect of (+)‐catechin on total phenolic content (TPC) and antioxidant properties in low‐fat hard cheese were examined over a 90‐day ripening period at 8 °C. Antioxidant activity (AA) in cheese was measured by ferric reducing antioxidant power, oxygen radical absorbance capacity (ORAC) and 2,2‐diphenyl‐1‐picrylhydrazyl assays and compared with TPC. Catechin retention coefficients in cheese curds were in the range of 0.63–0.75 and decreased the pH of cheese without affecting protein, fat or moisture content. Both TPC and AA increased during the 90‐day ripening period. Oxygen radical absorbance capacity was the most suitable technique for evaluating AA in cheese due to the high correlation with TPC and suitability in both lipophilic and hydrophilic systems.
- Sensory evaluations and stability determinations of goat milk containing galactooligosaccharides
The objectives of this study were to evaluate the feasibility of producing goat milk containing galactooligosaccharides (GOS) by β‐galactosidase and to determine the sensory attribute and stability of goat milk containing GOS. The results indicated that the maximum GOS obtained were approximately 13.9% of total sugars at pH 4.5 and temperature 40 °C. The sensory attribute of the obtained GOS was determined using a 5‐point hedonic scale in terms of taste, flavour, appearance and overall acceptability. There were significant increases in taste and overall acceptability of goat milk containing higher GOS concentration when compared to regular goat milk (control). Also, goat milk containing GOS presented a good stability over the acidic conditions. GOS in goat milk were also stable after the high heat treatment and shelf life conditions.
- Mass transfer kinetics and mathematical modelling of the osmotic dehydration of orange‐fleshed honeydew melon in corn syrup and sucrose solutions
A simple mathematical model to predict dehydration and impregnation process during osmotic dehydration of orange‐fleshed honeydew in sucrose and corn syrup solutions was proposed. Results showed low dispersion and a good fitting capability for WL and SG kinetics. Diffusivity values for WL ranged from 0.96 × 10−10 to 2.22 × 10−10 and 1.04 × 10−10 to 3.10 × 10−10 m2 s−1 in corn syrup and sucrose solutions, respectively. For SG, the obtained range was 0.72 × 10−10 to 2.35 × 10−10 and 0.71 × 10−10 to 2.46 × 10−10 m2 s−1 in corn syrup and sucrose solutions, respectively. The half‐life of dehydration rates (t1/2) was from 30.9 to 71.2 min and from 19.4 to 57.5 min in corn syrup and sucrose solutions, respectively. Diffusivities values obtained according to the proposed model were close to the ones observed from diffusive model; t1/2 was a promising criterion for the process time definition.
- Efficiency and safety evaluation of photodegradation of Aflatoxin B1 on peanut surface
A photodegradation study of Aflatoxin B1 (AFB1) on peanut surface was performed under UV irradiation at different UV irradiation intensities. With an initial quantity of 10 ng of AFB1, it can be degraded thoroughly within 80 min under the intensity of 800 μw cm−2. The photodegradation pathway of AFB1 on the peanut surface was proposed. Mutagenesis and cytotoxicity were assessed after exposure to different concentrations of AFB1 and the mixtures of photodegradation products on the peanut surface. The results of the Ames and in vitro cytotoxicity assay, providing clues to the assessment of safety issues of UV method applied in AFB1 decontamination, indicate that photodegradation products on the peanut surface has no toxicity, which can be explained by the differences in the chemical nature of the test compounds before and after UV irradiation.
- Bioactive action of β‐glucosidase enzyme of Bifidobacterium longum upon isoflavone glucosides present in soymilk
Bioconversion of isoflavone glucosides and antioxidant activity by probiotic strain (Bifidobacterium longum) during soymilk fermentation was investigated, as well as partial characterisation of the produced enzyme β‐glucosidase. The enzyme has higher affinity for genistin than for other substrates assayed. Maximum activity occurred at 42 °C and at pH 6.0; keeping 70–80% of activity for 60 days stored at low temperatures. Bifidobacterium longum grew well in soymilk (8.26 log CFU mL−1 and pH of 3.9 at 24 h) and were produced in good quantities of organic acids. High hydrolysis degree of isoflavone glucosides (81.2%) was observed at 24 h. Enhancements in bioactivity were assessed in fermented soymilk by monitoring the radical‐scavenging activity, antioxidant activity and DNA protective action. The use of probiotic Bifidobacterium strain as β‐glucosidase producer increased bioactive isoflavone content and demonstrated that this enzyme plays a key role in the bioavailability of soymilk isoflavones, reducing the bioconversion time compared to other studies.
- Composition of eggplant cultivars of the Occidental type and implications for the improvement of nutritional and functional quality
We have investigated the diversity for composition in seven eggplant (Solanum melongena) cultivars of the Occidental type. The results show that, with the exception of moisture content and pH, there is a wide diversity for all the analysed traits. Protein content was variable, but generally low. The content in available carbohydrates ranged between 2.99 and 4.19 mg 100 g−1, and the main soluble sugars were glucose and fructose. The fibre content was the most variable trait. In all cases, the dehydroascorbic acid content was higher than the ascorbic acid content. Total phenolics content was on average thirty‐nine‐fold higher than vitamin C content. Multivariate analysis showed that accessions from the black and striped groups presented a similar composition profile, while the white and pickling fruits were very distinct. The pickling eggplant H11 is identified as the best source for improving the nutritional and functional properties of Occidental eggplants.
- Degradation kinetics of rebaudioside A in various buffer solutions
Rebaudioside A is a noncaloric high‐intensity sweetener extracted from Stevia rebaudiana. For it to be used in foods, rebaudioside A needs to be stable during processing and storage. This study evaluated the kinetics of rebaudioside A degradation in 0.02 and 0.1 m citrate and phosphate buffer solutions at pH 3, 5 and 7 stored at 20, 30 and 40 °C for 9 months. At pH 3 and temperatures less than 30 °C, degradation was slow (i.e. less than 6% loss in 6 months) and not affected by buffer type or buffer concentration. At pH 7, the degradation of rebaudioside A increased dramatically in phosphate buffer (losses of up to 25% in 6 months at 30 °C), while remaining relatively slow in citrate buffer (less than 5% loss). The degradation rates at pH 7 increased 2.6 times as the concentration of phosphate buffer increased. For optimum stability of beverages containing rebaudioside A, formulations with lower concentrations of citrate buffer stored at lower temperatures are recommended.
- The effect of pH, salts and sugars on the rheological properties of cress seed (Lepidium sativum) gum
Effect of shear rate (15–600 s−1), gum concentration (1–2%), pH (3–9), sucrose (10–40%), lactose (5–15%), NaCl (100–300 mm) and CaCl2 (5–50 mm) was evaluated on apparent viscosity (ηa), flow behaviour index (n), consistency coefficient (K) and yield stress (τ0) indices of cress seed gum (CSG) solutions. Different rheological models were used to fit the experimental data, although the Herschel–Bulkley model was found the best model. An increase in gum concentration led to an increase in τ0, ηa, and k and a decrease in n values. The addition of salts lowered the k value; however, the n value showed slight significant change. The presence of sugar resulted in the enhancement of n, k, τ0 and ηap values. The existence of yield stress and pseudoplastic behaviour of CSG, its stability against salts, wide range of pH and synergic effect of sugar make it a good thickener and stabiliser in food formulations.
- Quantification of soluble solids in reconstituted açaí (Euterpe oleracea Mart.) pulp using near‐infrared spectroscopy
Açaí consumption is increasing worldwide because of the growing recognition of its nutritional and therapeutic properties. This product is classified based on its soluble solids content (SS), but the determination of SS in pulp is time consuming, tedious and not suitable for modern food processing plants. As near‐infrared (NIR) systems have been implemented to measure various quality attributes of food products, the objective of this study was to evaluate the feasibility of NIR diffuse reflectance spectroscopy to quantify the SS content of açaí pulp. Partial least squares (PLS) regression models were constructed to predict the SS. An optimum PLS model required one latent variable [principal component (PC)1 = 97%] with a root‐mean‐square error of calibration (RMSEC) of 1.06% for the calibration data set and the root‐mean‐square error of prediction (RMSEP) of 1.03% for internal cross‐validation. External validation using an independent data set showed good performance (RMSEP = 1.33% and Rp2 = 0.82). NIR spectroscopy is a reliable method with which to determine SS in açaí pulp and thereby to classify açaí pulp according to established minimum quality standards.
- Antimicrobial and antioxidant activities of different propolis samples from north‐western Algeria
The aim of this study was the investigation of antimicrobial and antioxidant activities of different ethanolic extracts of propolis (EEP) collected from north‐western Algeria. Total polyphenols and flavonoids contents of extracts were measured. The UV absorption spectrum showed and confirmed their polyphenols constituents. All EEPs exerted antibacterial activity against Gram‐positive bacteria, but no effect on Gram‐negative bacteria. The minimum inhibitory concentration (MIC) of EEPs ranged from 0.01% to 2.6% v/v. The antioxidant activity was measured using ferric‐reducing power (FRAP), 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) free radical‐scavenging and ESR methods. Propolis TIA‐2 and MOH‐MAS samples showed the highest antioxidative capacity, after 35 min, while TIA‐1, NED‐TL and SFS‐SBA samples showed the highest antioxidative potential of measured EEPs, after 3 min. TIA‐2 sample showed the highest antibacterial, antioxidant activity and highest DPPH free radical‐scavenging activity as well as the highest polyphenols and flavonoids content, compared with other propolis samples.
- Neural network models to classify olive oils within the protected denomination of origin framework
A computerised approach to vastly reduce the experimental information required (number of independent variables) to classify similar extra virgin olive oils (EVOOs) is presented. It is based on the application of a multilayer perceptron (MLP) and further analysis of the obtained results using differential calculations. To validate this new model, it has been applied for the classification of 147 EVOO samples into four similar families. The oil samples employed came from two types of protected denomination of origin (PDO) oils and two non‐PDO from the same Spanish province (Granada). This approach results in a new method that reduces the necessary size of the databases used, without an appreciable loss of information, by over 82%. The percentage of misclassifications using less data points is similar to the results achieved using the whole database (less than 0.90%).
- Starch fraction profiles of milled, nonparboiled rice varieties from Nigeria
This study determined the levels of nutritionally important starch fractions in selected milled, nonparboiled rice cultivated in Nigeria. Five improved varieties (FARO 52, FARO 57, FARO 44, FARO 60 and FARO 61) and four local varieties (Kwandala, Yardass, Jeep and Jamila) were evaluated. There were significant differences in starch fractions among varieties. Resistant starch (RS) ranged between 1.43% and 3.13%. Rapidly digestible starch (RDS) was lowest in Jamila (27.70%) and highest in FARO 61 (39.26%). Generally, the local varieties had significant higher RS (2.71%) with a lower RDS (32.82%) compared with improved varieties (RS; 1.88% and RDS; 36.07%). RS was inversely related to RDS and starch digestion index (SDI). The SDI had a highly significant positive correlation with RDS (r = 0.879, P < 0.01). These results highlight the need for further work in the identification of milled, nonparboiled rice varieties with less rapid digestion for its associated health benefits to consumers.
- A study on relationships between durum wheat semolina properties, technological mixing parameters and the properties of dough after mixing
Partial least square regression analysis was used to study the correlation between X variables (semolina quality, hydration level and mixing time) and Y variables, which were, in a first model, dough consistency during mixing, and, in a second model, dough properties after mixing (strength, elasticity, density) and leavening (maximum volume). The first model showed a predictive residual sum of squares (PRESS) of 2.98 and a predictive R2 (Q2) of 0.92, and highlighted the key role of hydration and mixing time on dough consistency. The second model had the best PRESS (8.25) and Q2 (0.94) values for dough volume and indicated that the volume increased with increasing mixing time until the dough consistency decreased of 20–30%. Dough volume was primarily affected by hydration. The model indicated that maximum volume after leavening, corresponding to optimum mixing time, was obtained with a soft and elastic dough, with a low‐density value.
- Ethyl carbamate formation regulated by ornithine transcarbamylase and urea metabolism in the processing of Chinese yellow rice wine
Ethyl carbamate (EC) is a potential carcinogenic compound present in most of the fermented foods. In this work, EC was inhibited through different strategies during vinification of Chinese yellow rice wine. EC can be inhibited by the use of ornithine in contrast to the control at peak point. However, the utilisation of urease resulted in little inhibitive effect on EC. The comparative data of intracellular ornithine transcarbamylase (OTCase) and arginine deiminase (ADI) among four experiments showed that EC was positively regulated by intracellular OTCase, but ADI was not determined. Extracellular urea and citrulline content was significantly increased by adding ornithine (P < 0.05), whereas ethanol played a minor role in EC formation. The correlation analysis between EC and OTCase or urea revealed a linear association (correlation coefficients above 0.8). These findings suggested that OTCase may be a required factor regulating EC formation during the brewing of Chinese yellow rice wine.
- Physical and cooking characteristics of black gram (Phaseolus mungoo L.) cultivars grown in India
Pulses are important component of diet, and information on their physical properties is needed for designing machines while cooking quality is important for consumer acceptance. Three black gram cultivars grown in India were evaluated for physical and cooking properties. Proximate composition revealed that three cultivars contained 24.5–26.7% protein, 1.1–1.3% fat, 2.8–3.7% ash and 60.4–63.3% carbohydrates. Length, breadth and thickness of seeds were in the range of 4.66–5.11 mm, 3.71–3.79 mm and 3.20–3.29 mm, respectively. True density and porosity varied from 1.25–1.29 g mL−1 to 33.43–36.09%, respectively. Hydration and swelling capacities of the seeds varied from 0.036–0.041 g per seed to 0.037–0.042 mL per seed, respectively. Cooking time of unsoaked seeds varied significantly from 35.3 to 42.7 min. Hardness and adhesiveness of the cooked seeds varied from 2.12–2.55 kg to 0.02–0.99 kg s, respectively. The black gram cultivars are rich in protein, and soaking treatment improved their cooking quality.
- Pasting and rheological properties of chia composites containing barley flour
The unique chia–barley composites contain omega‐3 polyunsaturated fatty acids (ω‐3 PUFAs) from chia and high β‐glucan content from barley that are well known for lowering blood cholesterol and preventing coronary heart disease. The pasting and rheological properties of chia and barley composites were characterised using Rapid Visco Analyser followed by an advanced rheometer. Shear‐thinning properties were observed for all the composites. The pasting and rheological properties of the products were not greatly influenced by 10% or 20% ground chia replacements but showed differences at the 50% replacement level. The results suggested that the elastic properties of chia–barley composites 1:1 with chia were improved by the chia component. Also, the chia–barley composites gave improved water‐holding capacities, particularly at the 50% level. Whole chia seeds are not easily utilised because of their hard coat. These fine particle composites should be helpful for preparing functional food products having enhanced health benefits.
- Stress relaxation behaviour of high acyl gellan gels
Stress relaxation behaviour of high acyl gellan gels has been investigated, and data were fitted successfully by a seven elements empirical model and a four term modified Maxwell model with three fixed relaxation times (20, 200 and 2000 s). In addition, the effect of testing parameters on stress relaxation characteristics and the relationship between those characteristics and intrinsic gel properties were studied. High acyl gellan gels were tested in stress relaxation with different cross‐head speeds (0.1–10 mm s−1) to applied strains (3–30%). The results showed that the cross‐head speed had little effect on stress relaxation behaviour of gels. With increasing the applied strain, the initial stress and the equilibrium stress increased. The equilibrium stresses from relaxation measurement were positively related to the hardness from TPA tests (R2 = 0.991). Relaxation appeared to be associated with the shifting of cross‐links in the gel matrix.
- Modelling growth of Lactobacillus plantarum and shelf life of vacuum‐packaged cooked chopped pork at different temperatures
Lactobacillus plantarum growth in a vacuum‐packaged cooked meat product under different storage temperatures (4, 10 and 16 °C) and the relation between the microorganism growth and sensory quality were investigated. The Gompertz model was fitted to experimental counts of L. plantarum showing a good fitting to growth curves at different temperatures. A root‐square secondary model and linear model were satisfactorily fitted to estimated growth rates (μ=0.01·(T+5.89)) and lag times (λ=0.17·1μ), respectively. The sensory attributes (colour, flavour, taste, appearance) were also evaluated due to their importance to the global quality (Q). The sensory deterioration was detected several days after L. plantarum reached the stationary phase, that is, 59, 45 and 25 days for 4, 10 and 16 °C, respectively. According to results, sensory deterioration was related to time when microorganism reached late stationary phase, phenomenon known as ‘delayed change’.
- Comparison of analytical methods for measuring proanthocyanidins in wines and their relationship with perceived astringency
The concentration of proanthocyanidins from twenty red wines from cv. Cabernet Sauvignon, five rosé wines from cv. Cabernet Sauvignon and five white wines from cv. Sauvignon Blanc was quantified using four analytical methodologies, and their relationship with the perceived astringency was investigated. Proanthocyanidin concentrations were determined by a methylcellulose precipitation assay, a protein precipitation assay and two colourimetric methods (Bate‐Smith and vanillin assay). The four methodologies showed high repeatability but differed widely in proanthocyanidin concentrations. The methylcellulose and protein precipitation assays could not quantify proanthocyanidins in rosé and white wines. The protein precipitation assay gave the lowest concentration of proanthocyanidins in all of the red wines. The methylcellulose precipitation assay (r = 0.7725; r2 = 0.59) and the protein precipitation assay (r = 0.6828; r2 = 0.47) showed a strong correlation with the perceived astringency compared with the colourimetric methods. The strong correlation of the methylcellulose precipitation method with the perceived astringency could be a useful tool to estimate red wine astringency.
- Rheological, gelling and emulsifying properties of a glycosylated and cross‐linked caseinate generated by transglutaminase
The impacts of oligochitosan glycosylation and cross‐linking on some properties of a commercial caseinate were investigated in this study. The glycosylated and cross‐linked caseinate with glucosamine content of 4.74 g kg−1 protein was generated by transglutaminase (TGase) and oligochitosan at pH 7.5 and 37 °C, with fixed substrate molar ratio of 1:3 (acyl donor to glucosamine acceptor), caseinate content of 50 g L−1, TGase of 10 kU kg−1 protein and reaction time of 3 h, respectively. In comparison with the caseinate, the glycosylated and cross‐linked caseinate had decreased reactable amino groups (0.58 vs. 0.51 mol kg−1 protein), higher apparent viscosity, decreased emulsifying activity index (about 14.5%) and statistically unchanged emulsion stability index (92.6 vs. 90.5%). Based on the mechanical spectra of the acid‐induced gels, the glycosylated and cross‐linked caseinate showed shorter gelation time (95 vs. 200 or 220 min) than the caseinate or cross‐linked caseinate. The gels prepared from the glycosylated and cross‐linked caseinate also had enhanced hardness, springiness and cohesiveness. The results indicated that TGase‐mediated oligochitosan glycosylation and cross‐linking has the potential to obtain new protein ingredients.
- Enzymatic and non‐enzymatic antioxidant systems of minimally processed cactus stems (Opuntia ficus‐indica Mill.) packaged under modified atmospheres
The aim of this work was to determine the enzymatic activities of catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX) together with the total phenolic and carotenoid contents and antioxidant capacity of two cultivars of cactus stems under modified atmosphere packaging containing a passive atmosphere, an active (with N2) atmosphere and control (unsealed polyurethane trays) all stored at 4 ± 1 °C. Results indicated that Atlixco cultivar cactus stems had a shelf life that was twice as long (20 days) than that of Milpa Alta cultivar under N2 MAP. The total enzyme activities of SOD, APX and CAT as well as the carotenoid content were higher in Atlixco than in Milpa Alta. The antioxidant enzymatic and non‐enzymatic systems as well as the antioxidant capacity and the phenolic content retention determined in Atlixco cactus stems under N2 MAP appear to explain the longer postharvest life of this cultivar.
- Influence of the addition of lupin sourdough with different lactobacilli on dough properties and bread quality
The aim of this research was to study the effects of solid‐state fermentation (SSF) with Lactobacillus sakei, Pediococcus pentosaceus and P. acidilactici on lupine sourdough parameters and lupine sourdough influence on the physical dough properties and wheat bread quality. The results showed that lactic acid bacteria (LAB) significantly reduced the pH and increased total titratable acidity (TTA) of SSF lupine. The highest protease activity in lupine is excreted by L. sakei (187.1 ± 8.6 PU g−1), and the highest amylase activity, by P. pentosaceus (155.8 ± 7.5 AU g−1). Lupine sourdough has a significant effect on the rheological properties of doughs, which affect the baking characteristics of the final product. In conclusion, it can be said that L. sakei, P. pentosaceus and P. acidilactici could be used for lupine SSF, and the addition of up to the 10% SSF lupine products increases the wheat–lupine bread quality.
- Effects of pasteurisation and storage on quality characteristics of table olives preserved in olive oil
Two types of products obtained from the processing of Olea europaea cv ‘Taggiasca’ were monitored: pitted olives and olive paste preserved in monovarietal extra‐virgin olive oil of the same variety. The aim of this study was to follow the trends in the main physico‐chemical and sensory parameters related to the quality of these table olives and their covering oils, for simulation of the shelf‐life conditions. From all of the analyses carried out, it can be concluded that the optimum time of storage of these two products packaged in glass jars at room temperature (between 18 and 25 °C) and under artificial light and away from heat sources is approximately 9 months. After 9 months of storage, the covering oils were greatly affected by the contact with the broken fruit, which was accompanied by reductions in their antioxidant content due to the thermal treatment. The oxidative effects seen through physico‐chemical analyses are in agreement with the organoleptic analysis.
- Effect of simulated gastrointestinal digestion on phenolic composition and antioxidant capacity of cooked cowpea (Vigna unguiculata) varieties
Consumption of diets rich in phenolic compounds has been associated with reduced risk of chronic diseases. The effect of cooking and simulated gastrointestinal digestion on phenolic compounds and antioxidant properties of two cowpea (Vigna unguiculata) types was determined. Phenolic acids, flavan‐3‐ols and flavonols were the main groups of phenolic compounds identified. Cooking and simulated enzyme digestion of the cooked cowpea samples rendered some phenolics less extractable (possibly by promoting binding with other food components) or more extractable (possibly by release of bound forms). Total phenolic contents and radical scavenging properties of the cowpeas were reduced upon cooking, but increased upon simulated enzyme digestion. Cowpea extracts inhibited human LDL oxidation at a concentration of 2 mg mL−1 possibly due to their phenolic content. Phenolic compounds in cowpea can potentially protect against cardiovascular diseases for which LDL oxidation is a risk factor.
- Contributions of phenolics and added vitamin C to the antioxidant capacity of pomegranate and grape juices: synergism and antagonism among constituents
The aim of this study was to examine the contribution of sugar, organic acid, neutral phenol, and anthocyanin fractions and added ascorbic acid to grape and pomegranate‐nectarine juice total phenol, oxygen radical absorbance capacity (ORAC), ferric reducing antioxidant power (FRAP) and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) values. Neutral phenol and anthocyanin fractions contributed ≥75% of the total antioxidant capacity (TAC) for both juices. Intrinsic synergy and antagonism among the fractionated constituents occurred inconsistently in each assay. Sugars and organic acids antagonised pomegranate juice neutral phenols and anthocyanins in the DPPH assay by 50% and the grape juice ORAC value by 21%, but were synergistic to the grape juice FRAP value. The added ascorbic acid was dose‐dependently synergistic with pomegranate and grape juice total phenol, DPPH and FRAP assays, but less so in the ORAC assay. Thus, the interactions between grape and pomegranate juice constituents determine TAC and total phenol values, and synergy in these assays could not be attributed solely to polyphenols.
- Hibiscus sabdariffa L. confesctionery gels, in vitro digestion, antioxidant activity and phenolic compounds quantification: a nutraceutical application
Dehydrated Hibiscus sabdariffa (Roselle) is usually used as the raw material of popular beverages, where the exhausted calyx, still rich in polyphenols and fibre, is discarded. The aim of the present study is to evaluate the possibility of adding Roselle's whole calyx to a confectionery product elaborated with gelatin, quantifying the concentration of released polyphenols (Folin–Ciocalteu) during an in vitro digestion and the expression of antioxidant activity [Ferric reducing antioxidant power (FRAP) and N,N‐dimethyl‐p‐phenylenediamine dihydrochloride (DMPD)] during this process. Results show that hardness and elongation of Roselle‐gelatin gums respond to a quadratic model where single components and binary mixtures show significant contributions to hardness and elongation behaviour respectively. Ten grams of Roselle‐gelatin gum express a higher antioxidant activity (FRAP) than 250 mL of the infusion prepared by a traditionally procedure. A significant proportion of the radical scavenging (DMPD) activity could have been lost during the elaboration process of the gums, and although more studies should be done, a hypothesis explaining this effect is included.
- Effects of waxy maize and potato starches on the stability and physicochemical properties of model sauces prepared with fresh beef meat
Stability and physicochemical properties of model sauces containing 2.5 wt% fresh beef meat (related to raw material), 30 wt% rapeseed oil and native waxy maize starch (WMS) or potato starch (PS) at concentrations ranged from 0.5 to 4.0 wt% were assessed. Sauces thickened with WMS showed a significantly (P < 0.05) higher stability than respective ones made with PS. All studied systems exhibited non‐Newtonian, pseudoplastic behaviour. The Ostwald–de Waele and Herschel–Bulkley models were used to describe the flow properties of model sauces. In comparison with control sample (prepared without starch), addition of this polysaccharide (WMS or PS) increased consistency index, yield stress and apparent viscosity and decreased flow behaviour index of model sauces. The Arrhenius equation was used to determine the effects of temperature (20–50 °C) on the apparent viscosity. The activation energy values were in ranges 7.66–10.59 kJ mol−1 and 8.87–11.82 kJ mol−1 in sauces prepared with WMS and PS, respectively. The instrumentally detected changes in consistency and whiteness of model sauces were found, which may be used as the good predictors of the perceived sensory consistency and whiteness.
- The influence of wine polymers on the spontaneous precipitation of calcium tartrate in a model wine solution
The influence of wine polymers on the spontaneous precipitation of calcium tartrate in a model wine system has been examined. Rhamnogalacturonan‐I was identified as the most effective inhibitor (precipitation induction time of 180 min compared with 7 min for the standard model). It is argued that this is a consequence of rhamnogalacturonan‐I's ability to participate in the ‘egg‐box’ type sequestration of calcium ions. The more structurally complex rhamnogalacturonan‐II had only a minor influence on the induction time (22 min). Arabinogalactan proteins and mannoproteins also have little influence with induction times ranging from 12 to 15 min. An ultra‐filtration study of four Chardonnay wines, prepared with and without the use of pectolytic enzymes, was performed in a search for conditions that might maximise the concentration of rhamnogalacturonan‐I. However, rhamnogalacturonan‐I could not be identified in any of the four wines. Implications of these observations, specifically the need to understand the inhibition exerted by specific uronic acids, for winemaking and calcium tartrate precipitation are discussed.
- Optimisation of the extraction conditions of natural colourant carthamin from safflower (Carthamus tinctorius L.) by response surface methodology
Alkali‐solution and acid‐isolation method (ASAI) and aqueous two‐phase system separation method (ATSS) have been reported to extract natural colourant carthamin from Carthamus tinctorius. In this study, these two methods were compared based on the optimisation results of extraction conditions by response surface methodology. In ASAI, the maximum extraction yield reached 0.779% at pH value of potassium carbonate solution of 11.16, ratio of potassium carbonate solution to raw material of fifteen and extraction time of 18 min, while 2.652% was achieved with concentration of acetone of 58%, ratio of acetone solution to raw material of twenty‐three and extraction time of 41 min in ATSS. From the point of view of extraction yield, ATSS had more superiority than ASAI. However, more pure carthamin was provided in ASAI according to HPLC assay. The obtained results in our experiments could be utilised for further researches of carthamin.
- The effect of lactic acid bacteria fermentation on the antioxidant activity of wheat gluten pancreatin hydrolysates
The antioxidant activities of the fermented wheat gluten hydrolysates with different fermentation times were investigated to elucidate the impact of lactic acid bacteria (LAB) fermentation on the wheat gluten hydrolysates. Prior to LAB fermentation, wheat gluten was deamidated by hydrochloric acid and then hydrolysed by pancreatin to 12 and 24 h, respectively. Results showed that LAB fermentation had significant impacts on the enzymatic efficiency and antioxidant activities of wheat gluten. The degree of hydrolysis and protein recovery of hydrolysates gradually increased and then reached maximum values, respectively, when fermenting with LAB for 36 h. The hydrolysis degree and protein recovery of fermented pancreatin 24‐h hydrolysates were larger than that of the fermented pancreatin 12‐h hydrolysates during the whole fermentation. The antioxidant activity analysis revealed a marked increase and improvement in the scavenging activities of 1,1‐Diphenyl‐2‐picrylhydrazyl·radicals, hydroxyl radicals and oxygen radical absorbance capacity, while the scavenging activities of ABTS+ radical decreased as the fermentation time extended. The antioxidant activities of pancreatin 24‐h hydrolysates were higher than that of the pancreatin 12‐h hydrolysates during the whole LAB fermentation.
- Changes of physicochemical and sensory characteristics of packed ripe table olives from Spanish cultivars during shelf‐life
Changes in the physicochemical and sensory characteristics of commercial plain (whole) and pitted ripe olives of the Gordal, Manzanilla, Hojiblanca and Cacereńa cultivars were studied during a three‐year period in conditions that mimicking the storage of such products in real life. No spoilage was developed during this period. Throughout the shelf‐life, the pH of the cover brines had a marked valley decrease at the beginning of storage followed by a progressive further decline, the surface colour (measured instrumentally) and firmness of the olives followed a first‐order kinetic decay, mitigated according to the iron and calcium contents. Also, a slight browning of the cover brines at the beginning of the storage was observed. No significant changes in most of the sensory characteristics were observed by the panel test during shelf‐life except for a limited change in olive surface colour. At the end of the shelf‐life, most of the samples were classified as ‘extra’ category according to the IOC sensory evaluation method and only plain Gordal presentation was classified as ‘first, choice or select’.
- Preparation and optimization of soy protein isolate–high methoxy pectin microcapsules loaded with Lactobacillus delbrueckii
This study was aimed to use soy protein isolate (SPI) and high methoxy pectin (HMP) as encapsulating materials for probiotic bacterial (Lactobacillus delbrueckii) delivery systems. The encapsulation conditions were optimised, and scanning electron microscopy (SEM) was used to characterise the microstructural changes of the microcapsule. The results showed that the optimal conditions for microcapsule preparation were 90 mg mL−1 SPI and 1 mg mL−1 HMP, with a SPI/HMP ratio of 7:1 (v/v), and a L. delbrueckii suspension to SPI–HMP complex ratio of 1:1 (v/v). The viability of the probiotics in the microcapsules reaching the small intestine was 3 log CFU mL−1 higher than that of naked bacteria. SEM showed that the surface of the SPI–HMP compound microcapsules was smooth and that a large number of L. delbrueckii could be seen in cross‐sections of the microcapsules.
- Influence of carbohydrates on self‐association of mung bean protein hydrolysate in the presence of amphiphilic asiatic acid
This study investigated the influence of surface‐inactive carbohydrates on association characteristics of amphiphilic mung bean protein hydrolysate (MPH) and asiatic acid (AA) in aqueous suspension (11.72–11.94% total solids). The carbohydrates investigated were trehalose, maltodextrin, mixed trehalose–maltodextrin and mixed maltodextrin–starch. The presence of low‐molecular‐weight carbohydrates enhanced micellisation of AA to form micrometre‐sized particles due to depletion flocculation. Nonetheless, the presence of starch retained the submicrometre size of AA. In contrast, the presence of starch enhanced self‐association of MPH via segregative phase separation. However, the mixed suspensions containing MPH, AA and carbohydrate in a ratio of 1:0–0.072:2.34, respectively, retained particle sizes of around 300 nm regardless of the carbohydrate used. It was found that the MPH–AA co‐aggregates were stable against the osmotic effect of carbohydrates. The results suggest that carbohydrates regulated the aggregate size and surface hydrophobic region of MPH and MPH–AA by controlling surface‐induced aggregation.
- Bioactive compounds, in vitro antioxidant capacity and Maillard reaction products of raw, boiled and fried garlic (Allium sativum L.)
Garlic is used in many dishes but some of its bioactive compounds are lost when exposed to heat. This study evaluated bioactive compounds, antioxidant activity and Maillard reaction products of raw (RG), boiled (BG) and fried garlic (FG). Total phenolic compounds, flavonoids, allicin and phytosterol were quantified as well as dietary fibres and mineral content. Antioxidant activities of RG, BG and FG were evaluated by oxygen radical absorbance capacity (ORAC), oxidation of β‐carotene/linoleic acid and Rancimat methods. The main results were the following: thermal processing of RG decreased both bioactive compounds and antioxidant capacity, boiling was found to be less aggressive than frying, and strong correlations were obtained between total phenolic compounds and the antioxidant assays. However, phytosterol content was higher in FG than in RG and BG and higher temperatures increased the formation of Maillard reaction products. It was concluded that RG and BG should be preferred for human consumption as they present higher antioxidant capacity.
- Viscous and thermal behaviour of vitamin A and iron‐fortified reconstituted rice
The viscous and thermal behaviour of five types of micronutrient‐fortified reconstituted rice premixes extruded at pre‐optimised extrusion conditions (36% moisture content, 150 rpm screw speed and 89 °C barrel temperature) have been investigated using rapid visco analyser (RVA) and differential scanning calorimetry (DSC). The highest peak viscosity (1279 cP), lowest gelatinised starch percentage (16.32) and highest enthalpy of gelatinisation (8.2 J g−1) were recorded in rice premix fortified with retinyl palmitate and micronised ferric pyrophosphate. The scanning electron microscopic analysis (SEM) also revealed that reconstituted rice premix fortified with iron (micronised ferric pyrophosphate) and retinyl palmitate was in closer resemblance to that of natural rice than any other reconstituted rice premix. The work demonstrated that vitamin A‐ and iron‐fortified reconstituted rice with meso/micro structure and pasting behaviour close to that of natural rice can be produced using retinyl palmitate and micronised ferric pyrophosphate as vitamin A and iron source, respectively.
- Optimisation of spray drying process parameters for low‐fat honey‐based milk powder with antioxidant activity
The purpose of this study was to optimise process parameters to prepare spray‐dried honey‐based milk powder containing functional properties of honey. Experimental design with temperature (180 to 200 °C), honey concentration (5–15%) and feed flow rate (8–10 rpm) as independent variables was studied to investigate the effect on product responses. Results showed that increasing the temperature resulted in powder with lower moisture, bulk density, antioxidant activity, total phenolic contents, total flavonoid contents and higher water solubility index. Increasing feed flow rate resulted in higher moisture, bulk density, antioxidant activity, reduced water solubility index, total phenolic content and total flavonoid content, whereas increasing honey concentration resulted in increase in antioxidant activity, total phenolic content and total flavonoid content. The moisture content, bulk density, water solubility index, DPPH scavenging activity, total phenolic content and total flavonoid content were 3.27%, 0.44 g cc−1, 96.67 g g−1, 17.45%, 2.54 GAE g−1 powder and 1.40 RE g−1 powder, respectively.
- Electronic nose evaluation of volatile emission of Chinese teas: from leaves to infusions
An electronic nose can be used to discriminate tealeaf quality, but to the best of the author's knowledge, studies that address the changes in electronic sensor signals between tea leaves and infusions are not available. In this framework, this preliminary work compared the volatile emissions of leaf samples belonging to the basic Chinese teas (white, yellow, green, oolong, black and pu erh) with those of their respective infusions using an electronic nose. Different signal responses were qualitatively and quantitatively obtained from the sensors both for the tea leaves and their respective infusions, showing that the leaf aroma is not transferred as it is into the beverage. The teas were grouped according to the different fermentation techniques based on the percentage variations in the sensor contributions to the complete description of the volatile profiles. The results indicated that the electronic nose is a suitable tool to monitor the volatile emission differences that occur between leaves and infusions in different tea types.
- In vitro inhibitory effects of cranberry bean (Phaseolus vulgaris L.) extracts on aldose reductase, α‐glucosidase and α‐amylase
The in vitro inhibitory activities of different seed extracts prepared from cranberry bean mutant SA‐05 and its wild‐type variety Hwachia against aldose reductase, α‐glucosidase and α‐amylase were examined. The results indicated that the polyphenolics‐rich extracts obtained using 800 g kg−1 methanol and 500 g kg−1 ethanol demonstrated inhibitory activities against aldose reductase (IC50 of 0.36–0.46 mg mL−1) and α‐glucosidase (IC50 of 1.32–1.94 mg mL−1). The 500 g kg−1 ethanol extracts also showed α‐amylase inhibitory activities (IC50 of 70.11–80.22 μg mL−1). Subsequent extracts, prepared further with NaCl and H2O from precipitates of 800 g kg−1 methanol or 500 g kg−1 ethanol extracts, exhibited potent α‐amylase inhibitory activities (IC50 of 17.68–38.68 μg mL−1). A combination of 500 g kg−1 ethanol extraction plus a subsequent H2O extraction produced highest polyphenolics and α‐amylase inhibitors. The SA‐05 α‐amylase inhibitor extracts showed greater inhibitory activities than that of Hwachia. Thus, cranberry bean mutant SA‐05 is an advantageous choice for producing anti‐hyperglycaemic compounds.
- The effect of storage on nutritional, textural and sensory characteristics of creamy ricotta made from whey as well as cow's milk and goat's milk
The aim of this study was to develop a creamy ricotta using a mixture of goat and cow whey as the main ingredients, with the addition of whole goat and cow milk. The nutritional composition, texture and sensory characteristics of the ricotta cheese were evaluated over 14 days of refrigerated storage. There was a decrease in protein and ash content and pH changes during the assessed storage periods. The instrumental texture profile indicated that the creamy ricotta was easily deformable, with minimal inelasticity and a cohesive, soft and delicate texture. The medium‐ and long‐chain fatty acid content was higher than the short‐chain fatty acid content. The flavour and aroma of creamy ricotta were described by the panel as having a soft texture and wet appearance. The use of whey from goat and cow cheese in making creamy ricotta is feasible and does not cause negative impact in the final product.
- Effect of harvest time and geographical area on sensory and instrumental texture profile of a PDO artichoke
A methodology of sensory and instrumental texture analysis was developed on a Protected Designation of Origin artichoke. Descriptive sensory analysis was applied on artichokes collected in two different geographical areas during the harvest time. Eight trained assessors evaluated the thistle odour, sweet, bitter, astringent, crunchy, fleshy and tender attributes. Instrumental texture, on artichoke heads and leaves, was evaluated with a texture analyser applying the cutting test and the texture profile analysis. The geographical area seems to affect the profile less than the harvest time. Instrumental texture analysis highlighted significant differences between the two geographical areas and during the harvest time. It can be assumed that, at the end of the biological cycle, artichokes are more suited to processing rather than for fresh consumption.
- The applied pretreatment (blanching, ascorbic acid) at the manufacture process affects the quality of nectarine purée processed by hydrostatic high pressure
A nectarine purée was manufactured with different pretreatments (thermal blanching or ascorbic acid – AA – addition), and then, the purée was processed by high‐pressure treatment to evaluate the effect of the initial manufacture conditions in the stability of the processed purées. A thermal treatment was also carried out to compare the effect with the high‐pressure processing (HPP). All applied processes were effective to ensure the microbiological safety of the purées. However, the pretreatment (thermal blanching or AA addition) applied during the manufacture affected the final quality of the processed purées. Initially, the AA addition had a protective effect on colour degradation during the manufacture of the purées; however, when these purées were treated by HPP showed less colour stability during storage, lower bioactive compounds content, and antioxidant activity. In contrast, purées with an initial thermal blanching maintained better the quality after HPP and during storage.
- Antioxidant activities of the fractionated protein hydrolysates from heat stable defatted rice bran
The hydrolysates from heat stable rice bran (HSDRB) treated by Alcalase 2.4L and Protease 500G were desalted and fractionated by hydrophobicity using a nonpolar, styrene divinylbenzene resin and macroporous adsorption resin DA201‐C. The antioxidant activities of HSDRB hydrolysates (HSDRBH) eluted by 25%, 50%, 75% and 100% ethanol were investigated using 2, 2‐di (4‐tertoctylphenyl)‐1‐picrylhydrazyl free radical‐scavenging activity assay, reducing power assay, ferrous ion‐chelating activity assay and lipid peroxidation inhibition assay. The HSDRBH‐75 had the highest reducing power assay and inhibition ratio of linoleic acid autoxidation, which might be associated with reduced molecular weight, amino acid composition and hydrophobicity. The highest metal‐chelating activity of four different fractions (at the concentration of 4 mg mL−1) had a positive correlation (r = 0.768, P = 0.116) with the total content of basic amino acid (Lys, Arg, and His) and a negative correlation (r = −0.886, P = 0.057) with the range of molecular weight (Mw < 1000 Da). The HSDRBH‐75 had the highest antioxidant activities in many assays, which suggests that it may become a good natural antioxidant as a food additive.
- Angiotensin I‐converting enzyme inhibitory activity of protein hydrolysates prepared from three freshwater carps (Catla catla, Labeo rohita and Cirrhinus mrigala) using Flavorzyme
Fish protein hydrolysates from three freshwater carps, Catla catla, Labeo rohita and Cirrhinus mrigala with different degree of hydrolysis (DH) (5%, 10%, 15% and 20%), were prepared using Flavorzyme enzyme and designated as HCF, HRF and HMF, respectively. The angiotensin I‐converting enzyme (ACE) inhibitory activity of hydrolysates was found to vary from 43 ± 2% to 71 ± 3%. Based on ACE inhibitory activity, HRF with DH‐15% was taken up for further study. The mode of ACE activity inhibition by HRF‐DH 15% was mixed type as revealed by Lineweaver–Burk plot. Sequential digestion of HRF‐DH 15% using pepsin and pancreatin decreased the ACE inhibitory activity from 76% to 63%. Partial purification of HRF‐DH 15% by size exclusion chromatography gave three different fractions designated as F‐1, F‐2 and F‐3 with the molecular mass in the range of 6456–407 Da. Fraction 2 had significantly higher ACE inhibitory activity than the other fractions.
- Selected factors influencing the ability of Bifidobacterium to form biogenic amines
The ability of typical probiotic culture of Bifidobacterium to produce biogenic amines could be considered a contrastive feature to the beneficial dietary effect on human health. The aim of this pilot study was to evaluate the decarboxylase activity of Bifidobacterium animalis subsp. lactis CCDM 239 influenced by selected factors (pH 4.5 and 5.0; the contents of NaCl 0–20.0 g L−1, glucose and lactose 0–10.0 g L−1) at in vitro conditions. The kinetics of the biogenic amine production under the above‐mentioned conditions was also monitored. The biogenic amine content detection was carried out in the supernatants of inoculated broth [MRS enriched with amino acids: arginine, ornithine, lysine, tyrosine; 3 g L−1 after the cultivation (48 h, 37 ± 1 °C)]. RP‐HPLC after the precolumn derivatisation with dansyl chloride was used. In most cases, the low concentrations of tyramine were monitored ( <15 mg L−1). Simultaneously, it was found out that the addition of certain fermentable saccharide concentrations and NaCl in their mutual combination seemed to have supporting effect on the decarboxylase activity of the tested Bifidobacterium.
- Effects of low‐temperature blanching on tissue firmness and cell wall strengthening during sweet potato flour processing
Free starch rate has been one of the most important criterions to evaluate the quality of sweet potato flour. Low‐temperature blanching (LTB) of sweet potatoes before steam cooking has shown significant increase in tissue firmness and cell wall strengthening. This research indicated that pectin methylesterase (PME) activity decreased by 87.8% after 30 min of blanching in water at 60 °C, while polygalacturonase (PG) and β‐amylase activity decreased 69.4% and 7.44%, respectively, under the same condition. Both PME and β‐amylase played important roles in tissue firmness. Further studies of tissue firmness and methyl esterification showed that the combination of LTB and Ca2+ could increase the activity of PME and significantly enhance the pectin gel hardness to strengthen the cell walls and decrease free starch rate from 12.83% to 7.28%.
- Modification of physiochemical properties of copra meal by dilute acid hydrolysis
Coconut residue or copra meal (CM), a by‐product after pressing cream and oil out of the coconut meat, is a good source of dietary fibre (DF), but high water‐holding capacity (WHC) of CM limits the quantity of fibre incorporated into food products. This study focused on the modification of CM physiochemical properties using acid hydrolysis to improve its potential utilisation as source of food fibres or low‐calories bulk ingredients in food applications. Acid hydrolysis using 0.5% HCl significantly reduced swelling capacity (SC) and water retention capacity, whereas bulk density (BD) and soluble DF content of the modified CM significantly increased. Monosaccharide composition profile, gel penetration profile and FT‐IR spectra indicated the destruction of CM matrix structure. This destruction increased compactness of the structure and lessened the ability of CM to hold water. Substituting the modified CM for wheat flour in bread and cookies significantly improved bread and cookies qualities compared with the use of the untreated CM. Response surface methodology showed that HCl concentration, hydrolysis temperature and time influenced properties of the modified CM. The models predicting their relationships were also generated.
- Comparison of rice bran oil and wax yields; a systematic approach to wax ester analysis
Rice bran oil (RBO) comprises 2–4% of rice bran wax (RBW) which contains wax esters (WE), hydrocarbons and other minor constituents, and there is still a lack of information on the RBW yields by various extraction methods and the WE contents in RBW. In this study, the yields of RBO and RBW extracted with Soxhlet and microwave‐assisted extraction (MAE) were compared with establish suitable RBW preparation methods. HPLC methods were also developed to determine the WE contents in RBW. MAE with hexane was the most efficient method for higher RBW yields as well as higher WE contents. The HPLC analysis proved that around half of the refined RBW consists of WE. The results established an efficient procedure for RBW preparation, which includes MAE with hexane, RBO refinement, winterisation, solvent fractionation and HPLC separation.
- Efficacy of different chemicals on shelf life extension of parsley stored at two temperatures
Four different chemical treatments, GA3, 1‐MCP, essential oils and nano‐Cu, were applied immediately after harvest to Petroselinum crispum (Mill) plants. The efficacy of the above chemicals on shelf life extension of parsley stored at 5 °C and 20 °C was determined by analysing physiological and biochemical factors that determine quality standards of storage fresh parsley. Nonsprayed parsley revealed the highest loss of weight, ascorbic acid, pigments and an enhancement of CO2 production and lipid peroxidation at 5 °C and 20 °C of storage. Nano‐Cu was more effective for delaying weight loss and revealed a better storage capacity. GA3, 1‐MCP and essential oils sprays were more effective in ascorbic acid retention at 20 °C than at 5 °C, whereas all substances protect samples from lipid peroxidation. Essential oils were more clearly inhibitory towards both total viable counts and yeast infection. Our results suggest that GA3, 1‐MCP, essential oils and Nano‐Cu exert their function through different mechanisms during ripening and could provide an effective and complementary means for maintaining high‐quality parsley leaves after harvest.
- Optimisation of convective drying of carrots using selected processing and quality indicators
The effect of drying temperature (40–65 °C) and air rate (2–6 m s−1) on the formation of Maillard reaction indicators and vitamins content of carrots dehydrated by convection has been investigated. The range of assayed processing conditions, based on a previous central composite face design (CCD), led to moderate changes in the studied parameters, even under the most severe conditions. In addition, the drying kinetic of the process was studied taking into account the experimental quantitation of shrinkage, which allowed the determination of a first drying period with a constant rate of water evaporation per unit of exchange surface. The slope of the first drying period, the moisture loss during the first hour of drying and the level of quality parameters (Maillard reaction indicators and vitamins) were correlated with processing conditions with high accuracy. For the prototype here used, the optima temperature and air rate to maximise the desirability function (0.77) were 46 °C and 4.9 m s−1.
- Flour and anthocyanin extracts of jaboticaba skins used as a natural dye in yogurt
This study used the flour and anthocyanin extracts from jaboticaba skins as a dye in yogurt. Jaboticaba skins were lyophilised and ground. Yogurt that was made in the conventional fashion was treated with the addition of flour from jaboticaba skins in the concentrations of 0.1%, 0.5%, 1.0%, 1.5% and 2.0% or with the anthocyanin extract in the concentrations of 0.5%, 1.0%, 1.5%, 2.0% and 2.5%, with and without tannic acid; the yogurt samples were stored for 45 days. In general, the results of the acceptance test of the yogurt samples ranged between like slightly and like moderately. The highest scores received by the anthocyanin extract (like slightly) were obtained for the concentrations of 0.5–1.5%. The colour retention for all yogurt samples was above 70%. The average half‐life was greater than 2500 h, considered high. We conclude that the use of jaboticaba skins as additives to yogurt can be an alternative to add value to jaboticaba.
- Biochemical properties and antioxidant activity of myofibrillar protein hydrolysates obtained from patin (Pangasius sutchi)
Antioxidant activities of myofibrillar protein hydrolysates (MPH) prepared from patin (Pangasius sutchi) using papain and Alcalase® 2.4 L with different degrees of hydrolysis (DH) were investigated. With a DH of 65.83%, the hydrolysate prepared with papain exhibited the maximum of 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical‐scavenging activity (71.14%) with a reducing power of 0.310. At a concentration of 1 mg mL−1, the papain‐MPH exhibited a Trolox equivalent antioxidant capacity (TEAC) of 70.50 ± 1.22 μmol g−1 protein. With a DH of 83.6%, the Alcalase‐MPH had the highest metal‐chelating activity. Low molecular weight peptides showed higher antioxidant activities than high molecular weight peptides. Both papain‐MPH and Alcalase‐MPH contained high amounts of the essential amino acids (48.71% and 48.10%, respectively) with glutamic acid, aspartic acid and lysine as the dominant amino acids. These results suggest that the protein hydrolysates derived from patin may be used as an antioxidative ingredient in both functional food and nutraceutical applications.
- The effect of linseed and psyllium fibre on the gelling properties of unwashed mince from farmed meagre (Argyrosomus regius)
The gelling properties of farmed meagre (Argyrosomus regius) mince mixed with linseed and/or psyllium fibres (up to 4.0%, w/w) were studied. The effects of chilled storage time (15 days vs. 1 day) and cold gelling (setting at 2 ± 2 °C) were measured. Linseed addition increased ω3 PUFA content and worsened the gel products' texture. Psyllium functional fibre addition had only a negative effect upon breaking force and deformation, not affecting the remaining textural properties and improving water‐holding capacity (WHC) from 61–77 to 70–85%. The incorporation of 4.0% (w/w) psyllium seems to be advisable. Quality of heat‐induced meagre gels was unaffected by chilled storage time. Production of an acceptable cold set gel is feasible provided that enough time is allowed for completion of the setting process. Overall results showed a potential for combining small‐sized meagre ( <2 kg) and psyllium fibres to produce high added‐value functional foods.
- Enzymatic grafting of gallate ester onto chitosan: evaluation of antioxidant and antibacterial activities
The antioxidant octyl gallate (OG) has been successfully grafted onto chitosan by means of horseradish peroxidase biocatalyst. The maximum gallate incorporation onto chitosan determined by 1H NMR spectroscopy was up to 16 molar%. The resulting materials displayed antioxidant capacities with DPPH radical inhibition percentage up to 23% upon the assay conditions. The grafting of the antioxidant on chitosan enhanced its antimicrobial activity. Minimal inhibitory concentration (MIC) for Escherichia coli was 0.5 g L−1. The native medium molecular weight chitosan alone or grafted with the lowest OG incorporation (ca. 11 molar%) attained 100% inhibition of E. coli, whereas lower inhibition was observed for all other materials 50.7–68.9% corresponding a reduction in the counts from 10.6 to 5.23–3.30 Log CFU mL−1. The inhibition of Listeria monocytogenes was significantly higher (59.8–100%) than that with the Gram negative bacterium reaching the MIC at 0.25 g L−1 with a reduction in the counts from 12.6 Log CFU mL−1 to 5.06–0 Log CFU mL−1.
- Reduction in hydroxymethylfurfural content in ‘churros’, a Spanish fried dough, by vacuum frying
This work explores the advantages of vacuum frying of ‘churros’, a Spanish dough pastry, compared to standard deep‐fat frying. Oil uptake, texture change, colour development, nonenzymatic browning and hydroxymethylfurfural (HMF) concentration were analysed at different frying conditions. The results obtained during vacuum frying at 100, 120 and 140 °C and 21 kPa were compared with those obtained at atmospheric pressure at 140 and 180 °C. For the same final water content, the vacuum fried ‘churros’ showed no significant differences in the fat uptake compared to those fried at atmospheric pressure (P > 0.05). However, the vacuum fried dough had a much crunchier texture. The evolution of the CIELab a* coordinate and the browning measurement at 280 nm show that vacuum frying is able to slow down the development of browning tones. Furthermore, products can be obtained with an HMF content <1 mg kg−1 of dry dough.
- Lycopene (Z) – isomers enrichment and separation
(All‐E)‐ Lycopene undergoes geometrical isomerisation into (Z)‐lycopene isomers with thermal treatment. Influence of three isomerisation methods including ethyl acetate reflux, microwave‐assisted reflux and ultrasound/microwave‐assisted reflux, and isolation of (all‐E)‐lycopene from other carotenoids and (Z) lycopene isomers through selective inclusion by deoxycholic acid (3α, 12α dihydroxy‐5βcolan‐24‐oic‐acid, DCA) were investigated. The results showed that microwave and ultrasound/microwave‐assisted reflux were not significantly different at P < 0.05, but both were significantly different (P < 0.05) over refluxing in ethyl acetate, proportion of (Z)‐lycopene isomers reached 54% after refluxing for 5 h. Heterogeneous mixture of isomerised tomato oleoresin containing 54% (Z)‐lycopene isomers and 40% (all‐E)‐lycopene and deoxycholic acid in dichloromethane was incubated at 25 °C for 2 h. Then, the mixture was filtered and from the filtrate 96.6% (Z)‐isomers enriched lycopene was obtained. The processes can be used in the production of enriched (Z)‐lycopene isomers for food supplements and functional food industry as a natural bioactive ingredient.
- Physicochemical, technological and sensory characteristics of a rice (Oryza sativa L.) and bean (Phaseolus vulgaris L.) soup prepared by extrusion
The aim of this work was to prepare and evaluate an instant soup formulated with broken rice and beans processed by thermoplastic extrusion using a pilot‐scale, single‐screw extruder. The final product was characterised regarding its physicochemical composition, amino acid profile, functional–technological properties and sensory performance. The extrusion parameters were set using three extrusion zone temperatures (30, 40 and 70 °C), a screw speed of 177 rpm, feed rate of 260 g min−1. and circular matrix of 3.85 mm. The final product contained considerable levels of protein (12.91 g per 100 g) and dietary fibre (8.07 g per 100 g). Amino acid profile analysis showed that only sulphur‐containing amino acids and tryptophan were limiting with the remaining present in adequate concentrations to meet children's requirements. Regarding functional and technological properties, the instant soup powder showed appropriate water solubility and water absorption indexes as expected. The soup sensory analysis indicated good acceptability, with a purchase intent index of 71%.
- Quality of fresh‐cut purple‐fleshed sweet potatoes after X‐ray irradiation treatment and refrigerated storage
The effect of X‐ray irradiation on the quality of fresh‐cut, refrigerated purple‐fleshed sweet potato (PFSP) cubes was investigated. Packaged sweet potato cubes were treated with 0, 250, 500, 750 or 1000 Gy X‐ray irradiation and stored at 4 ± 1 °C for 14 days. After 14 days, total aerobic bacteria counts were 4.1 and 3.2 log10 CFU g−1, and mould–yeast counts were 3.3 and 3.0 log10 CFU g−1 in 750 and 1000 Gy treated samples, respectively. Doses up to 1000 Gy did not affect the firmness, moisture content and anthocyanin content of PFSP cubes throughout storage. PFSP cubes' flesh colour did not change during the first week of storage, but lightness (L*) increased after 14 days. Also, irradiation doses at 750 and 1000 Gy decreased saturation (C*) significantly, producing duller flesh colour than controls. Results indicate that X‐ray irradiation treatment at doses up to 1000 Gy can reduce microbial populations while maintaining the physical quality and anthocyanin content of PFSP cubes up to 14 days of storage.
- Processing and storage effects on anthocyanin composition and antioxidant activity of jams produced with Camarosa strawberry
Anthocyanin profiles and radical scavenging activity of Camarosa strawberry jams as affected by two processing methods (conventional/industrial) and storage conditions were evaluated. Industrial strawberry jam produced in a closed system with vacuum preserved the anthocyanin composition (the total content was 35.77 ± 2.56 mg per 100 g) when compared with conventional jam produced in an open system (3.35 ± 0.05 mg per 100 g). However, the radical scavenging activity of conventional jam was lower than that of industrial jam, as EC50 was 52.99 ± 0.94 and 44.33 ± 2.47 mg mL−1, respectively. Two‐way analysis of variance indicated a significant effect of processing method and storage time during 60 days and a significant interaction for all variables except for EC50. Long‐time storage of industrial jams at −8 °C leads to 80% reduction in anthocyanin content without loss of sensorial characteristics, whereas at room temperature the reduction was 98%, and the red colour was replaced by a brownish. Regardless of storage temperature, the radical scavenging activity of jams decreased 50–60% of its initial value.
- Soft starchy candy as a food model to study the relationship between sensory and selected physicochemical properties
Soft starchy candy is a dessert with unique characteristics of thin sugar crust, soft internal texture and coconut milk flavour. Eight commercial samples were selected to represent commercially available products. Sensory liking were evaluated and analysed by preference mapping techniques. A lexicon consisting of 17 attributes was developed by a trained descriptive panel. Principal component analysis yielded four dimensions with 95.04% total variance explained. The product, having the highest liking scores in most of the sensory attributes evaluated, contained moisture and fat contents of 17.77% and 16.32%, respectively, which affected its aroma, flavour and texture. A significant relationship between sensory liking and some descriptive analysis attributes was observed. Sensory characteristics influencing overall liking were ‘coconut milk’ and ‘scented candle’ aroma and flavour, ‘hardness’ and ‘crust hardness’. This study revealed selected chemical composition and critical sensory attributes of soft starchy candy products that would help manufacturers develop acceptable products.
- Anthocyanin and organic acid profiles of pomegranate (Punica granatum L.) juices from registered varieties in Turkey
This is the first study to analyse the profiles of anthocyanin (ACN) and organic acid (OA) and some physico‐chemical properties of pomegranate juices (PJs) obtained from nine registered varieties in Turkey. HPLC analyses revealed that there were significant differences between ACN contents (28–447 mg L−1) and profiles (P < 0.01). The PJs contain maximum six ACNs, 3‐glucosides and 3,5‐diglucoside of delphinidin, cyanidin and pelargonidin. The major OA in PJs was citric acid (66–74%), followed by malic (6–12%), succinic (5–19%), nonidentified (0–14%) and tartaric acids (0.1–3.7%). Amongst individual OAs, citric acid had the most significant effects on TA (r = 0.9761), pH (r = 0.9208) values and sourness of PJs. As different from literature, results of this study revealed that malic acid contents of authentic PJs could be higher than 1.5 g L−1. Consequently, ACN and OA profiles could be successfully used in quality control because all PJs have their own typical ACN and OA profiles.
- Extractability of antioxidants from legume seed flour after cooking and in vitro gastrointestinal digestion in comparison with methanolic extraction of the unprocessed flour
Antioxidant activities were studied in methanolic and water extracts of nonprocessed, cooked and in vitro enzymatically digested seed flour, as well as in total protein hydrolysates and small peptide fractions ( <3 and <10 kDa) of three pea and five grass pea cultivars. The antioxidative properties were determined by three spectrophotometric methods: 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging assay, Folin‐Ciocalteu (FC) reducing capacity assay and H2O2 scavenging. We also applied one luminometric assay for hydroxyl radical scavenging. The study showed that cooking and enzymatic digestion strongly enhanced the release of phenolic compounds in methanolic extracts of four analysed cultivars. Scavenging activity against DPPH radical, hydroxyl radical and hydrogen peroxide was increased in majority of analysed flour specimens subjected to processing. Our findings indicate that, besides the phenolic compounds, the small peptide fraction, especially the MW <3 kDa, in methanolic and aqueous extracts of cooked and digested seed flour significantly contribute to free radical and hydrogen peroxide scavenging activity in all investigated cultivars. Our data strongly suggest that simple cooking treatment and in vitro digestion of seed flour applied prior to extraction with methanol could improve antioxidative activity of obtained extracts.
- Effect of heat treatment on internal atmosphere and leaf extension of minimally processed leek stalks
Leeks trimmed at 20 cm from their base were immersed in a 55 °C hot water bath. During the heat treatment (HT), the internal gases released from each stalk were collected, and their volume as well as CO2 and O2 concentrations were determined. After HT, cooling and storage at 10 °C for 8 days, the weight, maximum leaf extension and internal atmosphere (volume and gas composition) were measured. It was found that HT inhibited leaf extension during storage at 10 °C for 8 days and induced significant modification of the stalk internal atmosphere, both immediately after HT and after storage. Therefore, in heat‐treated leek stalks, the growth zone of the innermost leaves was subjected to an environment of elevated CO2 concentration, which was accompanied by the inhibition of leaf extension growth.
- Diosgenin quantification, characterisation and chemical composition in a tuber collection of Dioscorea spp. in the state of Jalisco, Mexico
Dioscorea spp. tubers are known commonly as camote de cerro to the state of Jalisco, México. Besides its use as food, it contains diosgenin, a raw material used widely for synthesising steroid hormones. The purpose of the present research was to determine diosgenin contents by gas chromatography‐mass spectrometry (GC‐MS), as well as physical and chemical characteristics of sixty Dioscorea spp. accessions cultivated in mesh shade coming from eleven localities in the state of Jalisco. Extraction protocol for diosgenin was maceration combined with ethanol 80%. Significant statistical differences for diosgenin content were found between accessions, finding levels between 0.02 and 0.16 mg kg−1 in dry basis. Length, weight tuber, proportion pulp/skin, percentage of pulp and percentage of skin showed significant differences. Chemical composition based in fresh weight presented in moisture percentage a range of 71.93–83.26%, crude protein 1.42–1.74%, ashes 0.80–1.16%, lipid 0.13–0.17%, crude fibre 3.80–4.02% and total carbohydrates 13.97–25.44%. Results show that tubers from Jalisco can be an important source of nutrients for consumers.
- Influence of aeration and agitation modes on solid‐state fermentation of apple pomace waste by Phanerochaete chrysosporium to produce ligninolytic enzymes and co‐extract polyphenols
The effect of different types of agitation (i) continuous agitation (C); (ii) continuous, discontinuous, continuous agitation (C/D/C); (iii) discontinuous, continuous, discontinuous agitation (D/C/D) and aeration (0.87, 1.25, 1.66 vvm) on ligninolytic enzyme production and polyphenolic compounds extraction by solid‐state cultures of Phanerochaete chrysosporium BKM‐F‐1767 was investigated. Higher production of manganese peroxidase (MnP) (1690.3 ± 87.6), lignin peroxidase (LiP) (387.9 ± 14.3) and laccase (898.9 ± 53.3 U gds−1) and liberation of total polyphenolics (ranging from 12.22 ± 1.1 to 30.12 ± 0.88 mg gallic acid equivalents per gram DW) was obtained after 195, 147, 219 and 204 h of fermentation, respectively, using 1.66 vvm as airflow and (C/D/C) agitation mode. Maximal enzyme production and total polyphenolic content were influenced by aeration, and higher values were obtained using 1.66 vvm as airflow rate, followed by 1.25 and 0.83 vvm, respectively. They were also influenced by agitation, and maximal values were obtained using C/D/C, followed by D/C/D and continuous agitation, respectively. The agitation modes influenced the production of ligninolytic enzymes and simultaneous extraction of polyphenols.
- Effect of commercial enzymatic preparation with pectolytic activities on conventional extraction and ultrasound‐assisted extraction of oil from grape seed (Vitis vinifera L.)
Conventional solvent extraction (CE) and ultrasound‐assisted extraction (UAE) in hexane for oil from untreated and enzyme‐treated grape seeds were investigated and compared. Among the output power tested (50, 100 and 150 W) in UAE on untreated seeds, UAE at 150 W for 30 min with liquid‐to‐solid ratio 8:1 (v/w) gave oil extraction yield comparable to CE (ca. 14% w/w) for 6 h with liquid‐to‐solid ratio 12:1 (v/w). CE and UAE at 150 W did not influence the fatty acid profiles of oil. CE oil was found to be the most oxidised. The enzymatic treatments (2, 4 and 6 g per 100 g seeds of Rapidase® Expression) prior to CE enhanced by 2.5% of the oil yield. Enzymatic treatments higher than 2 g per 100 g seeds increased relative value of some fatty acids both in CE and UAE. Enzymatic pretreatment from 2 to 4 g per 100 g seeds significantly improved some physicochemical parameters of oil quality when extracted by CE, but not by UAE.
- Quality attributes and firming kinetics of partially baked frozen wholewheat bread with sourdough
Partially baked frozen (PBF) process prolongs bread shelf life, but diminishes its volume and crumb texture. Therefore, we investigated the possibility of using sourdough for the quality improvement in PBF wholewheat bread. Sourdough was fermented with either Lactobacillus plantarum, Lb. brevis or Leuconostoc mesenteroides mixed with yeast Candida humilis and added at 7.5, 15, 22.5 or 30% on bread dough basis. The choice of sourdough starter significantly affected bread acidity characteristics, flavour, specific volume, shape and crumb firmness. The sourdough amount and acetic acid content of bread inversely correlated to flavour score, specific volume, shape and crumb softness. The overall quality of PBF wholewheat bread was most efficiently improved after adding Lb. plantarum sourdough at 15–22.5%, resulting in retarded firming rate (74–94%) and improved specific volume (25–28%) in comparison with PBF bread without sourdough. Such sourdough has lactic to acetic acid higher than previously recommended for traditional sourbreads.
- Characteristics and antioxidant activity of leaf essential oil–incorporated fish gelatin films as affected by surfactants
Characteristics of film from fish skin gelatin incorporated with four leaf essential oils (lemongrass, basil, citronella and kaffir lime), as influenced by different surfactants (Tween‐20, Tween‐80 and soy lecithin), were investigated. Films incorporated with all essential oils had lower tensile strength with higher elongation at break and thickness, compared with control film (P < 0.05). Films added with Tween‐20 showed higher TS, compared with those containing other surfactants (P < 0.05). Water vapour permeability of films incorporated with all essential oils markedly decreased in comparison with control (P < 0.05). Films generally became darker and more yellowness, when incorporated with essential oils. Film containing basil essential oil had the highest DPPH radical– and ABTS radical–scavenging activities, compared with those added with other essential oils. Higher antioxidative activity was obtained in films containing essential oils when soy lecithin was used as surfactant, probably due to the combined effect of both constituents.
- Release kinetics of antioxidant compounds from Hibiscus sabdariffa L. encapsulated in gelatin beads and coated with sodium alginate
Gelatin beads containing a concentrated extract of Roselle (Hibiscus sabdariffa L.) calyx rich in polyphenolic compounds were coated with sodium alginate and ionotropically gelled using CaCl2. Single‐coated beads and double‐coated beads were obtained by this technique, and the release pattern of the loaded extract was evaluated. As a result, release pattern of these compounds fits properly to a first–order Weibull distribution equation. The release rate constant decreased linearly with the number of alginate coats and with the increase in immersion time in CaCl2 and the Lag period increased significantly with the number of alginate coats. The release of H. sabdariffa's polyphenols can be well controlled manipulating the number of alginate coats and the immersion time in a CaCl2 solution, allowing not only to control the gastrointestinal segment where they could be released but also to control the release rate with the certainty that the initial concentration will be completely released showing a highly significant antioxidant activity as well.
- Physicochemical and antioxidative properties of Korean nanopowdered white ginseng
This study was carried out to investigate physicochemical and antioxidative properties of Korean nano white ginseng powder. The particle size of nanopowdered ginseng (NPG) was in the range from 600 to 1000 nm which was significantly smaller than the regular powdered ginseng (PG) which was in the range from 300 to 500 μm. Carbohydrate content was found to be significantly higher in NPG than PG (P < 0.05). Higher L value of NPG was mostly due to the higher light‐scattering effect of bright ginseng powder. In oil‐holding capacity, NPG was significantly higher than PG (P < 0.05). Total polyphenol content was not significantly different between NPG and PG, and it was in the range of 52.5% (P > 0.05). However, DPPH and ABTS studies showed that NPG has higher antioxidative properties than PG. In overall, NPG showed much higher antioxidative properties compared with PG. Thus, NPG enhances the functional value of Korean white ginseng powder.
- Effect of defatting and decortication on distribution of fatty acids, phenolic and antioxidant compounds in sorghum (Sorghum bicolor) bran fractions
Sorghum bran components could be a potential source of nutrients and phytochemicals for industrial applications. The effect of defatting with hexane and different degrees of decortication on distribution of fatty acids, phenolic compounds, colour (L, a and b) and antioxidant activity (DPPH) of red (RS) and white (WS) sorghums was studied. The decortication process was carried out at time intervals of 1–6 min. Defatted and nondefatted fractions were analysed. The content of polyunsaturated fatty acids (PUFA) was higher than monounsaturated fatty acids (MUFA); the content of MUFA was higher than saturated fatty acids (SFA). Linoleic, oleic and palmitic acids predominated in all fractions. Significant differences in the content of palmitic and linolenic acids between sorghums were found. RS had higher content of palmitic, and WS was higher in linoleic acid. Defatted samples contained lower amounts of phenolic compounds and higher antioxidant activities, than nondefatted samples. RS was a better source of total phenolic compounds and antioxidant activity compared with WS, but WS presented a more suitable profile of fatty acids. In conclusion, fractions of both types of sorghums can be used in cereal‐based products to enhance their phytochemical profile.
- Gluten‐free bread: multiple time–intensity analysis, physical characterisation and acceptance test
The formulation of gluten‐free breads is challenging, once the gluten network is responsible for the physical and sensory properties of bread. This study presents a novel concept for making gluten‐free breads using sugar substitutes. The quality of gluten‐free breads was analysed by means of physical (specific volume and colour), textural (firmness, elasticity and chewiness) and sensory properties (time‐intensity analysis and acceptance test). Time‐intensity analysis showed that the sample developed with raw sugar had a higher intensity of sweetness, and the sample with stevia had a higher intensity of yeast flavour. The sample with frutooligosaccharides (FOS) presented a higher acceptance by consumers. Sample with stevia presented the higher intensity of yeast flavour (8.10) and the lesser mean of specific volume (2.83 cm3.g−1); whereas sample with sugar who presented higher intensity of sweetness stimulus (5.20) also presented the higher mean of specific volume (3.80 cm3.g−1). The addition of prebiotic and sweetener opens up new opportunities to develop gluten‐free breads that may present similar properties to those of wheat‐based breads.
- Effect of sodium carbonate on appearance and textural properties of glutinous rice cake
The effect of sodium carbonate (Na2CO3) on the appearance and textural properties of glutinous rice cake was investigated. Glutinous rice kernels were soaked in Na2CO3 solution (0–1.2 N) at 25 °C for 24 h. Soaked rice was used for glutinous rice cake (GRC) production. The results showed that the rice soaked in Na2CO3 had lower protein and fat content, but higher ash content than those of untreated rice, while the amylose content in treated and untreated rice was not significantly different. Moreover, images from scanning electron microscopy showed that the starch granules from rice treated with Na2CO3 had smoother surfaces than untreated ones. From the alkali digestion test, the rice kernels treated with Na2CO3 suggest a lower gelatinization temperature than untreated rice. The GRC was uniform, and yellow colour was enhanced. Moreover, GRC exhibited an increase in softness and stickiness with increasing Na2CO3 concentration.
- Prebiotic fibre‐incorporated whey protein crisps processed by supercritical fluid extrusion
Prebiotic soluble fibre (fructooligosaccharides)‐incorporated whey protein crisps were produced by low‐shear supercritical fluid extrusion (SCFX), which utilises supercritical CO2 as an expansion agent instead of steam. Protein crisps with desirable qualities were obtained with a formulation containing 8% prebiotic fibre and 60% whey protein concentrate (WPC‐80), which gave the final product with a protein content of 49.6% (w/w). A maximum of 70% WPC‐80 and 8% prebiotic fibre could be incorporated to produce expanded protein crisps; however, increasing WPC‐80 from 50% to 70% decreased the end‐product expansion ratio from 3.1 to 1.2 and increased the product hardness and piece density from 1.3 to 2.8 kN and 0.63 to 0.75 g mL−1, respectively. Addition of 8% prebiotic fibre did not affect the textural qualities of final products. The process produced an expanded protein matrix with unique internal microstructure of uniformly distributed closed cells. Amino acid analysis indicated that 90% of the total lysine and 92% of the total essential amino acids were retained after SCFX processing and oven‐drying, indicating the preservation of protein nutritional quality during the process.
- Comparison of lipid and protein oxidation, total iron content and fatty acid profile of conventional and organic pork
The aim of the research was to compare differences in lipid and protein oxidation, total iron content and fatty acid profile in pork loin obtained from organic and conventionally reared pigs. The samples of organic meat were taken from breeding certified by the polish certifying body according to the Council Regulation (EC) no 834/2007 on organic production and labelling of organic products. The meat samples were examined at the following times post‐mortem: 2, 4, 7 days. Measurements of lipid oxidation showed that the organic meat samples were characterised by lower TBARS values during whole storage period (0.78–0.81 mg kg−1) compared with those of conventional system production (0.95–0.99 mg kg−1). Results of protein oxidation measurements of the organic meat sample were significantly lower (0.43 nmol mg−1 protein) at the beginning of experiment than those for the conventional meat sample (0.66 nmol mg−1 protein). It was also indicated that the production system had no effect on iron content and myoglobin oxidation during storage. In conclusion, obtained results pointed out that the organic pig meat was characterised by higher lipid stability during the whole storage time compared with meat from conventional production system.
- NaOH treatment reduces capsaicin content and pungency of ‘Makedoniko’ pepper (Capsicum annuum L.)
Pickled peppers are preferred by certain consumer groups at reduced pungency. To investigate the reduction in pepper pungency and capsaicin content, fresh ‘Makedoniko’ hot peppers were treated with 0, 0.5 or 1% NaOH before preserved in acid brine for 60 days. Pepper physicochemical traits were monitored following NaOH treatment and during preservation. Capsaicin content was measured in the beginning and at the end of preservation, and the peppers were also tested organoleptically. Preservation in acid brine induced the typical green–yellow product colour, increased firmness and decreased the dry mass in all treatments. NaOH‐treated pepper increased phenolics, chlorophyll and antioxidant content in dry mass during preservation faster than the control. Capsaicin content was reduced by 25 or 50% following 0.5 or 1% NaOH treatment, respectively. Pepper organoleptic pungency was also decreased following 1% NaOH treatment. NaOH reduces capsaicin content and pungency of ‘Makedoniko’ pepper, with minor effects on its processed product quality.
- Influence of viticultural practices and winemaking technologies on phenolic composition and sensory characteristics of Negroamaro red wines
The aim of this study was to assess the impact of some viticultural practices (VP) and winemaking technologies (WT) on phenolic composition and sensory characteristics of Negroamaro wines produced in Apulia, Southern Italy. Among VP, two soil management (cover crop and soil tillage) and two training systems (bilateral cordon and unilateral cordon) were compared, whereas among WT, three vinifications were tested: control (traditional, 7 days of maceration at 25 °C with two daily punching‐down), cryomaceration (24 h at 0 °C using dry ice) and ultrasound (37 kHz, 150 W, 15 min at 30 °C). Results showed that cover cropping decreased the concentration of flavonoids, whereas bilateral cordon training led to an increase of flavonoids and total polyphenols. Among technologies applied, the cryomaceration led to enrichment in anthocyanins and to impoverishment in total polyphenols, whereas ultrasound treatment improved the extraction of all phenol classes. Cryomacerated wines from the combination soil tillage and unilateral cordon were characterised by the best olfactory and gustatory sensory characteristics. Cryomaceration increased the notes of soft fruits and liquorice, whereas ultrasonic treatment did increase descriptors of violet, soft fruits and black pepper.
- Enhancement of the phytochemical and fibre content of beef patties with Himanthalia elongata seaweed
The effect of adding Himanthalia elongata seaweed (10–40% w/w) as a source of antioxidants and dietary fibre on physical, chemical, microbial and sensory traits of cooked beef patties was studied throughout chilled storage. Patties with seaweed showed reduced cooking losses and were nearly 50% more tender as compared to patties without seaweed. Microbiological counts and lipid oxidation were significantly lower in patties containing seaweed (P < 0.05), and by day 30 of storage, there was no bacterial growth in samples with ≥20% seaweed and lipid oxidation levels were low (0.61 mg malondialdehyde kg−1 of sample). Seaweed incorporation significantly increased the dietary fibre (1.64 g per 100 g fw in 40% seaweed patties), total phenolic content (up to 28.11 mg GAE per 100 g fw) and DPPH radical scavenging activity (up to 52.32%) of patties compared to the control. Sensory analysis indicated that the seaweed patties were accepted by consumers in terms of aroma, appearance, texture and taste. Patties containing 40% seaweed were rated highest in terms of overall acceptability, most likely due to improvement in texture and mouthfeel. Addition of seaweed in the formulation of beef patties leads to the enhancement of the nutritional and technological quality together with an acceptable sensory quality.
- Effects of microwave and ultrasound pretreatments on enzymolysis of milk protein concentrate with different enzymes
Milk protein concentrate was pretreated either by microwave irradiation or by ultrasound before initiation of 3‐h enzymatic hydrolysis. The duration of pretreatment ranged from 1 to 8 min at a power level of 800 W, with the control not being subjected to any pretreatment, and five enzymes (Alcalase, Trypsin, Neutrase, Alkaline Protease and Flavourzyme) were employed. The effects of microwave and ultrasound pretreatments on the kinetics and degree of hydrolysis, protein solubility, bitterness and angiotensin‐converting enzyme inhibitory activity were evaluated. Pretreatments increased the degree of hydrolysis and stabilised the solubility of the hydrolysates but could not significantly reduce bitterness of the hydrolysates The angiotensin‐converting enzyme inhibitory activity of the hydrolysates were improved with 5‐min ultrasound‐pretreated Neutrase hydrolysates giving IC50 value of 0.23 mg mL−1. Kinetic parameters showed improved catalytic efficiencies. Pretreatments of milk protein concentrates with either microwave or ultrasound significantly improve the bioactivity and functional characteristics of the resulting hydrolysates.
- Mango wine aroma enhancement by pulp contact and β‐glucosidase
This study determined the influence of pulp maceration and β‐glucosidase on mango wine physico‐chemical properties and volatile profiles. The distinction in pH, sugars and organic acids among different treatments was not statistically significant. All wine samples reached around 8% (v/v) ethanol from about 16% (w/v) of sugars. The wine with pulp contact contained about ten times higher α‐terpinolene and up to three times higher acetate esters than the wine without pulp contact, but mitigated the production of medium‐chain fatty acids and relative ethyl esters by up to six times. β‐glucosidase enhanced terpenols by up to ten times and acetate esters by up to three times. Furthermore, enzyme treatment mitigated, by up to five times, the formation of medium‐chain fatty acids and ethyl esters to moderate levels. Sensory evaluation showed pulp contact, and β‐glucosidase not only improved the intensity and complexity of wine aroma but balanced odour attributes.
- Spray drying of ACE‐inhibitory enzyme‐modified white cheese
An angiotensin‐I converting enzyme (ACE)‐inhibitory enzyme‐modified cheese (EMC) was spray‐dried at different inlet drying air temperatures, feeding pump rates and spraying air flow rates. Powder moisture content, bulk density, porosity, production yield and particles size were responses of interest measured. Response surface optimisation determined that if the cheese paste is pumped at feeding pump rate of 5%, sprayed with the compressed air at rate of 400 L h−1 and dried by an air at temperature of 154 °C, minimum moisture content is achieved for the produced powder. Spray drying decreased the ACE‐inhibitory of EMC significantly, but the powder was still extremely bioactive. Scanning electron microscopy (SEM) images revealed that inlet drying air temperature of 150 °C yielded a powder with relatively well‐separated particles. Higher drying air temperatures resulted in lower browning indices for the EMC powder.
- Effect of drying conditions on the retention of phenolic compounds, anthocyanins and antioxidant activity of roselle (Hibiscus sabdariffa L.) added to yogurt
To evaluate the use of lixiviate roselle calyxes as an alternative source of bioactive compounds, they were subjected to dehydration in a vibrofluidised bed dryer after which some chemical parameters such as the retention of monomeric anthocyanins (MA), phenolic compounds, polymeric colour and antioxidant activity were determined. Drying curves showed both a constant drying period and a decreasing falling rate period. The different drying conditions showed significant differences in the chemical parameters. Using the dry residue with the best bioactive compounds content, it was possible to develop a dairy beverage (yogurt). The results confirmed that lixiviated roselle calyxes could be a competitive alternative for traditional products, such as grapes or bilberries, in terms on their antioxidant activity and stability when it is added as a source of bioactive compounds.
- Preliminary studies on microbial polysaccharides from different Penicillium species as flavour stabiliser in cloudy apple juice
This research deals with the production of water‐soluble polysaccharides from six polysaccharide‐producing Penicillium species. Eup. pinetorum ATCC 14770 was promising for exo‐ and endopolysaccharides production under various cultural conditions. pH 5.0, 7 days, and pH 8.0, 10 days, were the optimum for the production of exo‐ and endopolysaccharides, respectively, at 30 °C in medium containing glucose and peptone. HPLC results revealed that both polysaccharides were composed of pectin, cellulose and hemicellulose. Exopolysaccharides produced by Eup. pinetorum was subjected to evaluation as a natural flavour stabiliser in cloudy apple juice (CAJ). Twenty‐one volatile compounds classified into esters, aldehydes, alcohols and ketone were detected, only eighteen compounds of which were characterised by their odours threshold. The esters and alcohols are accounting for 87.64% and 5.44% of total volatiles, respectively. This study indicates that the use of exopolysaccharides as an alternative flavour stabiliser in CAJ is very promising.
- Antibacterial mode of action of seed essential oil of Eleutherococcus senticosus against foodborne pathogens
This study investigated the antibacterial mechanism of action of the seed essential oil of Eleutherococcus senticosus (ESEO) against foodborne pathogenic bacteria. Preliminarily, the ESEO (1000 μg disc−1) showed potential antibacterial effect as diameter of inhibition zones (12.0 ± 0.2–37.0 ± 2.0 mm) against the tested foodborne pathogens. The MIC and MBC values of ESEO against the tested bacteria were found in the range of 125–500 and 500–1000 μg mL−1, respectively. At MIC concentration, the ESEO had potential inhibitory effect on the cell viability of the tested pathogens. In addition, SEM analysis showed the inhibitory effect of ESEO as confirmed by considerable morphological alterations on the cell wall of B. cereus ATCC 13061 and E. coli O157:H7 ATCC 43889. Moreover, the ESEO revealed its mode of action against foodborne pathogens on membrane integrity as confirmed by release of extracellular ATP, 260‐nm absorbing materials and leakage of potassium ions. These findings confirm that the ESEO can be used as a potential antibacterial agent in food industry to inhibit the growth of various foodborne pathogens.
- Combined acid‐ and rennet‐induced gelation of a mixed soya milk–cow's milk system
The objective of this study was to better understand the gelation behaviour of a mixed soya milk–cow's milk system, by forming different reactive protein particles using rennet and glucono‐δ‐lactone. The formation of the structure of these mixed gels was followed, for the first time, using diffusing wave spectroscopy and rheology. When only one protein source was induced to gel, protein aggregation was hindered, as shown by the slower increase in apparent radius after the gel point. Confocal microscopy analysis of the gel networks suggested that while milk gels exhibited large pores with interconnecting strands of protein, soya gels appeared as densely packed protein aggregates, and mixed soya milk gels appeared as a network of aggregated proteins. This study demonstrated that by modulating the reactivity of the building blocks, it is possible to fine‐tune structure formation of these mixed protein gels.
- Evaluation of parameters affecting modified atmosphere packaging engineering design for pomegranate arils
This study evaluated the effects of passive modified atmosphere packaging design parameters as a function of the amount of product (g), temperature (°C) and time (days) on two pomegranate cultivars. Arils (75, 100 and 125 g) were packed in trays, heat sealed with polylid film and stored at 5, 10 and 15 °C for 14 days, and analysed for physicochemical parameters viz headspace gas composition, weight loss, total soluble solids, titratable acidity, pH, anthocyanin, aerobic‐mesophilic bacterial and fungal load (log CFU g−1). At the highest temperature and weight, O2 concentration continuously decreased below the critical limit (2%) after 4 days, while at 5 °C, this lower limit was not reached. Shelf life of arils was limited to 10, 7 and 3 days by fungal growth ≥2 log CFU g−1 at 5, 10 and 15 °C, respectively. Using unsteady‐state equation, a good agreement was found between simulated and experimental gas composition data.
- Microwave‐assisted extraction and antioxidant activity of star anise oil from Illicium verum Hook.f
In this study, microwave‐assisted extraction with ethanol (MAEE) of star anise oil from Illicium verum Hook.f. has been optimised by response surface methodology (RSM). A maximum yield of star anise oil was obtained at an optimum condition: the ratio of solvent to sample 17 mL g−1, extraction time 16 min and microwave power 505 W. Accordingly, the highest yield of star anise oil was about 24.98%, which was much higher than that of steam distillation (SD), 7.17%. Oxygenated organic compounds in representative of trans‐anethole are a major component in star anise oil, nearly 94.21% for SD and 86.66% for MAEE, identified and determined by GC‐MS. The oils extracted by SD and MAEE both have strong antioxidant activities that were demonstrated by the DPPH and ABTS assays.
- Physicochemical characterisation and oxidative stability of refined hoki oil, unrefined hoki oil and unrefined tuna oil
Physicochemical characterisation and oxidative stability of refined hoki oil, unrefined hoki oil and unrefined tuna oil were carried out in the present study. Tuna oil contains a higher percentage of polyunsaturated fatty acids (42.57%) than the hoki oils (28.79–30.13%), which have higher percentages of monounsaturated fatty acids (45.02–47.16%). All oils showed a good ratio of n‐3 to n‐6 fatty acid (7.01–8.10). Cholesterol contents in the unrefined hoki (5149.40 μg g−1) and tuna (2045.48 μg g−1) oils were higher than the refined hoki oil (1411.27 μg g−1). Tuna has a higher concentration of natural α‐tocopherol (752.49 μg g−1) but lower concentration of vitamin A (110.99 μg g−1) than unrefined hoki oil (151.44 μg g−1 and 997.60 μg g−1, respectively). Higher percentages of unsaponifiable matter were found in the hoki oils (4.90–7.24%) compared with the tuna oil (0.56%). The hoki oils appear more yellow than the tuna oil, which is darker by comparison. Moisture, p‐anisidine value and free fatty acid contents in the hoki oils were lower than the tuna oil. Other indicators of oxidative stability showed that the hoki oils were more stable than the tuna oil.
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- Effect of storage on the bioactive compounds and antioxidant activity of quince nectar
The changes of bioactive components and antioxidant activity of quince nectar were determined during 9 months of storage at 5, 20, 30 and 40 °C. The amount of total phenolics, flavonoids and antioxidant activity was significantly declined during storage at all temperatures. Loss of L‐ascorbic acid at 5, 20, 30 and 40 °C was 32.08%, 43.69%, 65.21% and 88.82%, respectively. L‐ascorbic acid degradation was in accordance with the first‐order reaction kinetics, and activation energy was found as 43.65 kJ mol−1. After 9 months of storage, Hydroxymethylfurfural (HMF) contents of quince nectars were 15.01, 16.64, 21.69 and 57.89 mg kg−1 at 5, 20, 30 and 40 °C, respectively. HMF accumulation fitted a zero‐order kinetic model, and activation energy was found as 88.30 kJ mol−1. A significant correlation was found among L‐ascorbic acid, total phenolics, flavonoids and antioxidant activity.
- Drying kinetics and thermal degradation of phenolic compounds and anthocyanins in pomegranate arils dried under vacuum conditions
The effect of temperature and pretreatment on drying kinetics and thermal degradation of phytonutrients present in pomegranate arils was investigated. The arils were divided into two groups, and half of the samples were pretreated by dipping into 80 °C hot water for 2 min. The drying process was conducted in the vacuum drier at the temperatures of 55, 65 and 75 °C. The fastest drying was completed at 75 °C after pretreatment of the samples. The highest anthocyanin–phenolic compound contents and antioxidant capacity were detected in the arils dried at 55 °C. Seven thin‐layer drying models were used to predict drying curves, and Arrhenius and Eyring–Polanyi models were employed to predict phytonutrient degradation kinetics. Activation energy for drying was 24.26 kJ mol−1 for pretreated samples and 31.54 kJ mol−1 for untreated samples. Effective moisture diffusivities were ranged from 1.43 × 10−9 to 6.03 × 10−9 m2 s−1.
- Acid adaptation to improve viability and X‐prolyl dipeptidyl aminopeptidase activity of the probiotic bacterium Lactobacillus fermentum HA6 exposed to simulated gastrointestinal tract conditions
In this work, the viability of the probiotic bacterium Lactobacillus fermentum HA6 isolated from naturally fermented vegetables in Vietnam was improved by growing the bacterium into a mild acid condition (pH 4.0). Viability and probiotic functionality [X‐prolyl dipeptidyl aminopeptidase (PepX) activity] of the acid‐adapted bacterium exposed to simulated gastrointestinal conditions were investigated. After 180 min in the simulated gastric juice (0.3 g/L pepsin, pH 2.0), the viability of acid‐adapted L. fermentum HA6 (11.5%) was higher than that of control L. fermentum HA6 (2.2%). Specific PepX activity of acid‐adapted cells (24.5 U/mg) was higher than that of control cells (17.8 U/mg). After 180‐min exposure to the simulated small intestinal medium (0.3 g/L bile salts, 0.1 g/L pancreatin, pH 8.0), the viability of acid‐adapted L. fermentum HA6 (13.5%) was twofold as high as that of control L fermentum HA6 (8.0%). Our results suggested that acid adaptation has a key role in acquiring cross‐protection mechanism, which in this study resulted in higher survival of L. fermentum HA6 after simulated gastrointestinal stresses. The strategy of acid adaptation could be valuable for the production of robust probiotics.
- Lactic acid production using waste generated from sweet potato processing
Organic waste generated from industrial sweet potato canning is estimated to be 30% of incoming raw material with significant residual carbohydrate content. The purpose of this study was to evaluate the potential of waste generated from sweet potato processing material to support the growth of lactic acid bacteria and the production of lactic acid. The waste was comprised of 16.5% solids consisting of 18.5% ash, 4.4% protein, 20.5% simple sugars and 19% soluble starch. Following a screening of three lactic acid bacteria strains, Lactobacillus rhamnosus was deemed the best candidate for lactic acid production. The potential of various dilutions of the enzyme‐hydrolysed waste, with and without pH control, as a fermentation substrate was evaluated. Lactic acid production was highest in hydrolysed waste (without dilution) at pH set point 5.0, yielding 10 g L−1 in 72 h. Thus, lactic acid, a valuable organic compound, can be generated from sweet potato waste.
- Relationship between physicochemical and functional properties of amaranth (Amaranthus hypochondriacus) protein isolates
Protein isolates from six amaranth lines/cultivars (APIs) were evaluated to study their physicochemical (hunter colour, protein content and zeta potential), structural (thermal and conformational) and functional (emulsification, foaming, water and fat absorption) properties. APIs had protein content, whiteness index and gel temperature in range of 79.4–85.4%, 41.17–54.26 and 87.8–91.8 °C, respectively. The Fourier‐transform infrared spectra of APIs revealed α‐helix, β‐sheets and random coil conformations in the secondary structure. APIs with higher relative proportion of β‐sheets had higher Differential Scanning Calorimeter denaturation temperature and gel temperature. Minimum protein solubility (PS) was observed at pH 5.0, indicating isoelectric point (pI) of amaranth proteins. The PS, emulsifying activity index (EAI), emulsifying stability index (ESI), foaming capacity (FC) and foam stability (FS) of APIs at neutral pH were related to their zeta potential (ζ). The emulsifying and foaming properties were also determined at different pHs (between 2.0 and 9.0). The EAI‐pH profile of APIs confirmed close relationship between the emulsifying ability and PS.
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- Investigating the in vitro bioaccessibility of polyphenols in fresh and sun‐dried figs (Ficus carica L.)
In this study, in order to evaluate the in vitro bioaccessibility of fresh and sun‐dried figs, total antioxidant capacity (TAC), total proanthocyanidin content (TPA) and the major phenolic compounds were determined at different phases of simulated gastrointestinal (GI) tract digestion for Sarilop and Bursa siyahi fig varieties. Four major phenolic compounds (chlorogenic acid, rutin, cyanidin‐3‐glucoside (C3G) and cyanidin‐3‐rutinoside (C3R)) were investigated for GI tract digestion. The results of in vitro GI tract digestion revealed that the dialysed fraction (IN) represented 9–26% and 1–22% of the initial TAC of the whole‐fresh yellow and purple figs, respectively. Moreover, in case of 2,2‐azinobis(3‐ethylbenzothiazoline)‐6‐sulphonic acid (ABTS), TPA and chlorogenic acid contents, drying caused an increase in the IN fraction of yellow figs (38, 140, 50%, respectively). The bioaccessibility of C3G and C3R were quite low for fresh figs (0–5% of the initial values), whereas for dried figs, anthocyanins were not detected at all in the IN fraction.
- The impact of strawflower and mistletoe extract on quality properties of rainbow trout fillets
Many plants, including strawflower and mistletoe, contain antioxidants and antimicrobials, which can increase the shelf life of seafood. The main aim of this study was to investigate the effect of mistletoe and strawflower extracts at doses of 0.5% (w/v) on the sensory, chemical and microbiological properties of rainbow trout fillets during 27 days of storage at 2 ± 1 °C. The phenolic compounds in these plants have been studied, but their effects on food quality and storage properties have not been reported. We found that extract of mistletoe did not extend the shelf life of the fillets; however, the strawflower extract show high antimicrobial activity in fish fillets. The shelf life of rainbow trout was 20 days for the control and fish treated with mistletoe extract and 23 days for fish treated with strawflower extract. The antioxidant effect of extracts on fish fillets was weak, whereas strawflower extract had high antimicrobial effect. Peroxide value (PV) and thiobarbituric acid (TBA) values fluctuated during storage periods around main values below 14 meq O2 kg−1 and 0.6 MA kg−1, respectively. Putrescine, cadaverine, spermine, spermidine, serotonin, tyramine and dopamine were main amine, whereas histamine accumulated at low levels ( <2 mg per 100 g). Strawflower suppressed biogenic amine accumulation in fish fillets. At the limit of acceptability, total viable count (TVC), Enterobacteriaceae and lactic acid bacteria count remained below 7.6, 6.83 and 8.01 log CFU g−1, respectively. The results of this study show that ethanol extracts of strawflower improve the shelf life of rainbow trout.
- Biochemical composition of broccoli seeds and sprouts at different stages of seedling development
The proximate composition, amino acids content, fatty acid profile, total polyphenols, total flavonoids, DPPH radical scavenging capacity and sulforaphane content in broccoli seeds and sprouts were evaluated in this study. The results showed significant differences in the nutritional composition and the phytochemical level in the different stages of germination. Aspartic acid, glutamic acid, serine‐histidine, proline and threonine were found in larger concentrations. Polyphenols and flavonoids content ranged from 9 to 77 mg GAE g−1 and 33 to 117 μg QE g−1, respectively. DPPH radical scavenging capacity ranged from 174 to 674 μmol TE g−1. The sulforaphane content in seeds and sprouts ranged from 273 to 3632 μg g−1–the highest values were found in seeds and the 8‐ and 11‐day‐old sprouts. The results suggest that the broccoli sprouts are a rich source of nutrients and phytochemicals, these have a high potential as functional food.
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- The effect of high hydrostatic pressure processing on the extraction, retention and stability of anthocyanins and flavonols contents of berry fruits and berry juices
Anthocyanins and flavonols are types of phenolic compounds. Previous researches showed that phenolic compounds are relevant to the quality of plant‐derived foods and beverages. Any food‐processing technologies, which can preserve phenolic compounds after processing, should be taken into account for increasing the food quality. High hydrostatic pressure processing (HHPP) is a novel nonthermal process. There are some researches about the effect of HHPP on total phenolic content, total monomeric anthocyanins, kaempferol, myricetin and quercetin contents of berry fruits and berry juices in the literature. These studies showed that HHPP could possibly have a success potential in increasing the extraction, retention and stability of anthocyanins and flavonols contents of berry fruits and berry juices by preserving phenolic compounds after food processing. The aim of this review is to put forward how high hydrostatic pressure processing affects extraction, retention and stability of anthocyanins and flavonols of berry fruits and juices.
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- Preparation and characterisation of gellan/pullulan composite blend films
- Effect of dense‐phase CO2 on polyphenoloxidase in model solutions