Abstract
19 Streptococcus thermophilus with high exopolysaccharide production were isolated from traditional Chinese fermented dairy products. The exopolysaccharide and viscosity of milk fermented by these 19 isolates were assayed. The strains of Streptococcus thermophilus zlw TM11 were selected because its fermented milk had the highest exopolysaccharide content (380 mg/L) and viscosity (7716 mpa/s). Then Streptococcus thermophilus zlw TM11 was combined with Lactobacillus delbrueckii subsp. bulgaricus 3 4.5 and the combination was named SH-1. The quality of the yogurt fermented by SH-1 and two commercial starter cultures (YO-MIX 465, YF-L711) were compared. It was shown that the exopolysaccharide content of yogurt fermented by SH-1 was similar to that of yogurt fermented by YF-L711 and significantly higher than YO-MIX 465 (p < 0.05). In addition, the yogurt fermented by SH-1 had the lowest syneresis (8.5%) and better texture and sensory than the samples fermented by YO-MIX 465 and YF-L711. It manifested that the selected higher exopolysaccharide production starter SH-1 could be used as yogurt starter and reduce the amount of adding stabilizer, which can compare with the imported commercial starter culture.
Highlights
Yogurt has been an integral part of everyday diet for centuries, rising as the second most popular snack among children in the world [1]
The exopolysaccharide production and the viscosity of fermented cow milk produced by the 19 Streptococcus thermophilus isolated from traditional Chinese fermented dairy products were assayed
The results showed that the correlation coefficient between exopolysaccharide production and viscosity was 0.841 (p < 0.01)
Summary
Yogurt has been an integral part of everyday diet for centuries, rising as the second most popular snack among children in the world [1]. Many methods have been used to improve the quality of the yogurt, such as increasing the solids in milk (adding fat, proteins, or sugars such as sucrose and fructose), addition of stabilizers (pectin, starch, alginate, and gelatin) [6, 7]. These approaches did not satisfy the consumers demand for products with as few food additives as possible. EPS produced by LAB have gained considerable attention in the fermented dairy industry because of their potential application as viscosifiers, texturizers, and emulsifying agents [8]. It is significant to select the strains with higher EPS production
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
