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Oxidation in living organs causes dangerous diseases, including cancer, and in food, it causes spoilage and heavy economic losses. Synthetic antioxidants have adverse and dangerous effects on human health, therefore identifying natural antioxidant compounds is one of the main needs of the food industry. In fish processing industries, about 50-70% of fish, which are potential sources of valuable nutritional com such as essential amino acids, are produced as waste. Therefore, finding a way to optimally use these wastes and produce healthy compounds with high added value such as bioactive peptides has great importance. In this research, the effect of hydrolysis conditions (time: 30-300 min and enzyme concentration 0.5-3 %) and type of protease (alcalase and pancreatin) on the degree of hydrolysis and antioxidant properties (DPPH radical scavenging activity, Fe chelating activity, nitric oxide radical inhibition, total antioxidant capacity and Fe reducing power) of protein hydrolysate from skipjack viscera was investigated using the response surface methodology. The results showed that the optimum conditions for achieving the most antioxidant properties with alcalase and pancreatin were: hydrolysis time of 146.9 and 171.67 minutes and enzyme concentration of 1.94 and 2.17%; in these conditions, the degree of hydrolysis of the produced protein hydrolysates was 25.12% and 20.35%, respectively. Comparing the antioxidant properties of hydrolysates produced by both proteases showed that the alcalase enzyme led to the production of protein hydrolysates with stronger antioxidant properties than pancreatin. Therefore, it can be concluded that the protein hydrolysate of the skipjack fish viscera using alcalase enzyme as a healthy and value-added product can be used in the production of functional products and health supplements. [ABSTRACT FROM AUTHOR]

The impact of relative humidity (RH) and temperature on the effectiveness of acetic acid (AC) and essential oils of Carum copticum and Satureja khuzestanica in the vapor phase against pathogens was investigated. Inoculated peanuts were exposed to antimicrobial vapors at three humidity levels (63 ± 1, 75 ± 0, and 84 ± 1%) and three temperatures (25, 37, and 50°C) for 0, 1, and 2 hr. Results showed that increasing the RH, temperature, and fumigation time significantly affected the inhibition rate of the mentioned vapors. The highest inhibitory effect was observed under vaporizing condition including 84 ± 1% RH and 50°C, which reduced the initial population of Bacillus cereus, Staphylococcus aureus, Shigella dysenteriae, and Salmonella Typhi (8.1–8.3 log CFU/g) to 1.1, 0.5, 2.7, and 1.0 log CFU/g after 2 hr exposure to AC vapors, respectively. The results provide a promising approach to increase the inhibition rate of antimicrobial compounds in the vapor phase. Novelty impact statement: Increasing the RH significantly enhanced the inhibition rate. The microbial inactivation level is enhanced with the increase of temperature. Vapors of AC exhibited higher antimicrobial activity than the two studied essential oils. [ABSTRACT FROM AUTHOR]

Summary: In the present study, the effects of continuous and pulsed ultrasound (100 W, 30 kHz, 25–75% amplitudes for 30 min) and fermentation process (37°C for 24 h) by Lactobacillus helveticus PTCC 1332 on biological activities of Chortan were investigated. The obtained results showed that fermentation enhanced protease content (36.27% (neutral), 37.57% (acid), 39.28% (alkaline) protease), peptide concentration (45.27%) and antioxidant activity (33.69% (DPPH), 132.85% (ABTS)) of samples compared to unfermented ones. Additionally, an increase in ultrasound amplitude (except for continuous at 75%) promoted the protease enzymes, peptides and radical scavenging activity of the fermented and unfermented samples. Our results indicated that the ultrasound and fermentation treatments complemented each other. Depending on the experimental conditions, the effect of continuous ultrasound on samples was sometimes lower, sometimes similar and sometimes higher than that of pulsed treatment. Therefore, selection of an appropriate ultrasound mode and amplitude can improve the biological activity of Chortan. [ABSTRACT FROM AUTHOR]

Summary: Aflatoxin M1 (AFM1) and ochratoxin A (OTA) are two main mycotoxins in milk and dairy products. In the present work, the ability of four Lactobacillus strains (L. plantarum PTCC 1058, L. plantarum LP3, L. plantarum AF1 and L. plantarum LU5) to remove AFM1 and OTA in fermented cream was studied during 24 h fermentation. The antifungal activity of the mentioned lactobacilli against the defined fungi (Aspergillus flavus PTCC 5004, Aspergillus parasiticus PTCC 5018, Aspergillus nidulans PTCC 5014, Aspergillus ochraceus PTCC 5060) was also evaluated. The results showed that the cell counts of all strains were increased by 64–70% during fermentation. All Lactobacillus strains decreased the amount of AFM1 significantly (P ≤ 0.05) in the range of 26–52%, which the highest AFM1‐reducing effect was related to L. plantarum LU5 (from 0.5 to 0.24 μg kg−1). The mean OTA removal by Lactobacillus strains in fermented cream also ranged from 32 to 58%. Amongst Lactobacillus strains, the cell‐free culture supernatants of L. plantarum LU5 showed the highest (inhibition zone of 26.7 ± 1.2 mm) and L. plantarum LP3 and L. plantarum PTCC 1058 the lowest antifungal activities. The fermented creams contained Lactobacillus strains exhibited the highest and lowest antifungal activities against A. ochraceus and A. parasiticus, respectively. L. plantarum LU5, with the inhibition zone of 27.6 ± 0.9 mm, was the most effective fungal inhibitor, while L. plantarum PTCC 1058 had the lowest antifungal activity. Effect of fermentation on mycotoxins. [ABSTRACT FROM AUTHOR]

BACKGROUND The functional characteristics of hydrocolloids are mainly dependent on their physicochemical properties. Thus, it is essential to characterize the new sources of hydrocolloids. RESULTS: Quince seed gum (QSG) is a high‐molecular‐weight polysaccharide (9.61 × 106 g mol−1) composed of 85.04 ± 2.87% carbohydrate (6.39% l‐arabinose, 40.43% d‐xylose, 5.60% d‐galactose, 5.75% d‐glucose and 31.11% d‐mannose), 13.16 ± 1.73% uronic acid, 5.77 ± 0.83% moisture, 2.78 ± 0.21% protein, 5.64 ± 0.21% ash, and 0.75 ± 0.09% fat. Our findings indicated that this gum could be introduced as a value‐added by‐product in the food and pharmaceutical industries. Carbon‐13 nuclear magnetic resonance and Fourier transform infrared spectroscopy suggested a highly substituted xylan structure for QSG. In the dilute regime, an increase in the ion concentration was accompanied by a decrease in intrinsic viscosity of QSG. When the salt concentration increased from 0 to 50 mmol L−1, the consistency coefficient (as a measure of apparent viscosity) declined. On the other hand, with further increasing of salt concentration, the consistency coefficient (as a measure of apparent viscosity) values increased. Similarly, the G′ and G″ values for 10 and 50 mmol L−1 calcium chloride concentrations were less than in control samples. CONCLUSION: The rheological behavior of the QSG studied in this paper can provide insight into its potential application in food and pharmaceutical industries. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The effect of ultrasound (100 W, 30 kHz, 25% amplitude for 5, 10, and 15 min; US) on growth, carbohydrate metabolism, and antioxidant activity of probiotic Lactobacillus plantarum AF1 was investigated during milk fermentation. The antioxidant activity of L. plantarum AF1 was measured by 2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulfonate) (ABTS), 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), inhibition of the autoxidation of ascorbate, reducing ability, and superoxide anion radical scavenging activity tests. The results indicated that the cell membrane permeability of sonicated samples was increased 88–94% compared to control. Additionally, β‐galactosidase activity and population of Lactobacillus strain increased with increasing ultrasound treatment time during the fermentation after the treatment. However, no significant differences were observed in the final counts of the control and the sonicated samples at the end of fermentation (24 hr). Although the lactose content was decreased significantly (p ≤ .05) by extending sonication time, the amounts of glucose, galactose, and lactic acid enhanced significantly (p ≤ .05) as the time of fermentation and sonication proceeded. The antioxidant activity was also enhanced significantly (p ≤ .05) with increase in sonication time during 24 hr fermentation after the treatment. Therefore, the lowest and the highest antioxidant activities were seen in the control sample and the US‐15 min sonicated milk at the end of fermentation, respectively. Practical applications: The dairy industry is seeking methods to increase nutritional and quality of dairy products. Recently, the ultrasound has attracted significant attention in food processing generally because of the recent consumers' trend toward functional foods. The present study provides an investigation about the efficiency of ultrasound to improve the metabolism and growth of Lactobacillus plantarum during fermentation of milk and therefore increase the quality and antioxidant activity of milk. The results show that ultrasound is a potential technique for improve metabolism of Lactobacillus strain and thus increase antioxidant activity and quality of fermented milk. Consequently, the use of ultrasound will increase the health promoting effects and quality of fermented dairy products. These results will assist in designing ultrasound procedures for optimizing the general quality of fermented milk. [ABSTRACT FROM AUTHOR]