Abstract:

Streptococcus thermophlius StCH-1, a strain capable of rapidly producing acid and EPS-producing S. thermophlius
StTA040, a strain with an improved ability to produce exopolysaccharides (EPS) were individually or together co-cultured with
L. bulgaricus strain (Lb0925B) to investigate their fermentation characteristics. The influence of mixed strains on
fermentation curves, EPS production, post-acidification, viscosity, water-holding capacity and sensory quality of fermented
milk was investigated. The results showed that the fermentation time was significantly shortened by the combined use
of the strains especially in the presence of StCH-1. The combined strains containing StTA040 could produce more
exopolysaccharides (EPS) and consequently higher viscosity and water-holding capacity in fermented milk. In addition,
the combination of all these three strains accelerated the fermentation process and produced fermented milk with higher
viscosity and water-holding capacity and the best taste and flavor by sensory evaluation.

Key words: Streptococcus thermophilus, exopolysaccharides, co-culture, fermention properties, sensory evaluation