Effect of Lactobacilli on the Quality of Hydrolyzed Collagen Yogurt

In order to improve the quality and nutritional value of yogurt and evaluate the effect of Lactobacillus on the quality of pig skin hydrolyzed collagen yogurt, milk and pig skin hydrolyzed collagen were used as raw materials, and Lactobacillus plantarum, Lactobacillus casei, Lactobacillus rhamnosus and Bifidobacterium breve were used to prepare collagen yogurt, and its pH, acidity, color, texture, total bacterial count and sensory properties were measured. Results showed that compared with yogurt without added hydrolyzed collagen, collagen yogurt fermented by Lactobacillus casei significantly (P<0.05) improved the water holding capacity, pH, hardness and titratable acidity of the yogurt, and extended the storage time of the yogurt. Collagen yogurt fermented by Lactobacillus plantarum subsp. significantly (P<0.05) improved the water-holding capacity, pH, hardness and titratable acidity of the yogurt, reduced the adhesiveness of the yogurt, and increased the brightness value (L^*) and yellowness of the yogurt degree value (b^*), which reduced the redness value (a^*) of yogurt and increased the sweetness of yogurt products. Collagen yogurt fermented by Lactobacillus rhamnosus significantly (P<0.05) increased the yellowness value (b^*) and titrated acidity of the yogurt, but the total number of bacterial colonies decreased with the increase of storage time. Collagen yogurt fermented by Bifidobacterium breve significantly (P<0.05) increased the pH, titrated acidity and yellowness value (b^*) of yogurt, but had no effect on the textural properties of yogurt. In summary, Lactobacillus casei and Lactobacillus plantarum subspecies were suitable for making collagen yogurt. This research could add new vitality to the diversity of yogurt, and also provide an important theoretical reference for the development of healthier and nutritious yogurt products.