Comparative analysis of fermentability and rheological properties of two strains of exopolysaccharide-producing Kazachstania unispora from Tibetan kefir

This study was based on two strains of exopolysaccharide-producing Kazachstania unispora from Tibetan kefir as object. The exopolysaccharide content, fermentability and rheological properties of two strains were evaluated. The results showed that Kazachstania unispora of two strains had high ability to produce exopolysaccharide, and exopolysaccharide content of J₇ was 350.02 mg/L, which was higher than J₅. The fermentation characteristic of strain J₇ was better than that of strain J₅, and the fermented milk of strain J₇ had better organization status and flavor and sensory score was 84. The result of rheological properties showed that the fermented milk of strain J₇ had relatively higher apparent viscosity which was compared with strain J₅.Fermented milk of two strains were the thixotropic fluid, and thixotropic loop area of fermented milk of J₅ and J₇ was 377.63(1/s Pa)and 346.96(1/s Pa), which illustrated that the fermented milk of J₇ had stronger ability of structural resilience. The values of G' were higher than G″of fermented milk from two strains which showed similar solid properties, and fermented milk of J₇ had higher viscous and elastic. By comparing their exopolysaccharide-producing, fermentability and rheological properties, the result showed that the strain J₇ had higher fermentability and rheological properties, which could lay a foundation for the application of strains.