Impact of sturgeon gelatin hydrolysates (SGH) on physicochemical and microbiological properties of fat-free set-type yogurt

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 (τ0). 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.