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Polylactic acid (PLA) nanocellulose (NC) composite film and probiotic bacteria Lactobacillus casei were used to increase the shelf life of beluga fillet at refrigerator temperature (4 ± 1 °C). First, the physical and mechanical properties of the films (1: PLA, 2: PLA-NC, 3: PLA-NC + L. casei) were investigated. Then the packed fillets (with the mentioned films) and control (without film) were evaluated in terms of chemical (PV, TBA, TVB-N, and pH), microbial (TVC, lactic acid bacteria, and Enterobacteriaceae) and sensory properties on days 0, 4, 8, 12 and 16. According to the results, the addition of L.casei improved the physical properties of the film, but it harmed the opacity and mechanical properties. With the increase of storage time in the refrigerator, the viability of L. casei in the film decreased and its values were equal to 6.12 log CFU/g (at the end of storage time), however, it was within the permissible range (6 log CFU/g). Furthermore, the chemical, microbial, and sensory properties in the packed fillets were significantly lower than the control (P < 0.05). The best results were observed in PLA-NC + L. casei (P < 0.05), according to the suggested acceptable limit for these properties, this treatment was able to be maintained until the end of the storage period. All in all, the use of PLA-NC + L.casei had a positive effect on improving the quality of beluga fillets during refrigerated storage, and it can be a suitable method for the production of probiotic films. [ABSTRACT FROM AUTHOR]

In this study, the effect of free and microencapsulation of Tragopogon Collins extract (TPE) on the properties of probiotic yogurt was investigated. For this purpose, first, TPE was extracted by ultrasound method. The amounts of phenolic and flavonoid compounds in TPE were 890.04 mg/g gallic acid and 512.76 mg/g extract (respectively), and it had high antioxidant and antimicrobial properties. Then, the extract was encapsulated by maltodextrin–whey protein concentrate. The results related to the particle size, zeta‐potential, and microencapsulation efficiency of the TPE microencapsulation were 93.87 nm, 18.99 MV, and 64.35% respectively. In order to investigate the effect of nano‐ and free TPE on the properties of yogurt during a 15‐day storage period of 5 treatments including control, nano‐ and free TPE at 750 and 1,000 ppm were provided and the physicochemical properties, probiotic bacteria viability, and sensory properties were investigated. The results showed that adding TPE to yogurt affects the physicochemical properties, probiotic bacterial viability, and sensory properties were investigated. The results showed that adding TPE to yogurt affects the physicochemical properties. TPE samples had lower pH, less syneresis, and more acidity, viscosity, and antioxidant properties compared to the control sample (p <.05). Furthermore, in these samples, the viability of probiotic bacteria during storage was higher than the control treatment and the sensory properties were acceptable. In most cases, better results were observed in nano‐TPE treatment. Therefore, by industrial production of probiotic yogurt containing nano‐TPE as a functional food, a new choice will be provided for consumers of dairy products that would have more desirable nutritional value and sensory properties. [ABSTRACT FROM AUTHOR]

In this study, the effect of grape seed protein hydrolysate (GPH) on the physicochemical and sensory properties of stirred yogurt was evaluated. At first, the antioxidant properties and degree of hydrolysis (DH) of GPH were determined using the microbial protease enzymes (alcalase and flavourzyme), the results showed that alcalase enzyme can produce GPH with higher DH and antioxidant properties (p <.05). Also, increasing the hydrolysis time had a positive effect on these properties (p <.05). The DH, free radical scavenging DPPH, and ferric reducing power for GPH by alcalase at 30 min was 21.51%, 88.68%, and 0.33 μmol ferrous/ g, respectively. Therefore, this treatment was used for further experiments. In the next part, the mentioned GPH was added to the stirred yogurt with three concentrations (0.5, 1.5, and 1.5%) and physicochemical properties and viability of Lactobacillus casei and sensory properties were measured during 15 days of storage. The results showed that the GPH treatment had higher pH, viscosity, and texture firmness and less acidity and syneresis compared with the control sample (p <.05). Also, in these samples, the decreasing trend of L. casei viability was slower than the control treatment during the storage period (p <.05). In most parameters, better results were observed with increasing the concentration GPH and all the treatments were acceptable in terms of sensory properties. Therefore, by producing yogurt containing GPH, a new functional food can be provided for consumers of dairy products, which in addition to the desired taste, good nutritional properties can be also achieved from its consumption. [ABSTRACT FROM AUTHOR]