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Gelatin was extracted from beluga sturgeon (Huso huso, SG) and the effects of sturgeon gelatin hydrolysates (SGH) on physicochemical, textural, and rheological properties of yogurt during 28 days of refrigerated storage were explored in this study. SGH at 2 g/dL in yogurt showed the best survival of Lactobacillus bulgaricus , Streptococcus thermophilus , and Bifidobacterium lactis. Based on the results, SGH at 1 g/dL significantly decreased the flow behavior index (n) while increasing the values of k (consistency coefficient), complex viscosity (η*), and yield stress (τ 0). Dynamic shear rheological properties indicated higher storage modulus (G′), loss modulus (G″), and η * values at all frequency values compared to control (Yc) whereas Ysgh1 g/dL (yogurt with added SG and SGH) had a better solid-like behavior and elastic gel structure. Ysgh had a higher acidification rate during fermentation and water-holding capacity compared to Yc. However, syneresis and hardness increased and decreased at 2 g/dL SGH, respectively. Overall, SGH might be useful as the potential natural ingredients of fat-free set-type yogurt. • Sturgeon gelatin hydrolysates increased the fermentation rate and were associated with lower syneresis. • Sturgeon gelatin hydrolysates caused more solid-like behavior and elastic gel structure, especially at 1 g/dL. • Yogurt containing 1 g/dL sturgeon gelatin hydrolysates showed the highest hardness, adhesiveness and springiness. [ABSTRACT FROM AUTHOR]

Microencapsulation, as one of the most modern methods, has a significant effect on the survival of probiotic bacteria. The present study aimed to determine an optimal formulation for Lactobacillus rhamnosus ATCC 7469 microencapsulation by freeze-drying and using Whey protein isolate, (WPI) crystalline nanocellulose (CNC) and inulin (INU) as wall materials, which can improve the survival of probiotic bacteria against the gastrointestinal condition. For this purpose, WPI, CNC, and INU were used as wall components for the encapsulation of L. rhamnosus ATCC 7469 by mixture design. Then the optimal formulation (WPI: 57.22%, CNC: 25.00%, INU: 17.78%) was determined for minimization of Z-average and zeta potential, as well as maximization of encapsulation efficiency and viability after 60 min at simulated gastrointestinal condition using numerical optimization. FTIR and SEM tests were performed to investigate the interaction between the wall compounds and the surface morphology of the capsules. The selected optimum capsule significantly improved the survivability of probiotic bacteria in simulated gastrointestinal conditions (p < 0.05). • L. rhamnosus ATCC 7469 successfully was microencapsulated in WPI/CNC/INU biocomposite. • The ratio of WPI/CNC/INU in microcapsules wall were optimized by mixture design. • The viability of the microencapsulated L. rhamnosus ATCC 7469 was studied at gastrointestinal condition. • SEM and FTIR tests were used to characterize the properties of the microcapsules. [ABSTRACT FROM AUTHOR]