Structural characterisation of EPS of Streptococcus thermophilus S-3 and its application in milk fermentation.
- 2021-05
- International Journal of Biological Macromolecules 178
- Zhiyuan Xu
- Q. Guo
- Hui Zhang
- Z. Xiong
- Xiu-jie Zhang
- Lian-zhong Ai
- PubMed: 33639187
- DOI: 10.1016/j.ijbiomac.2021.02.173
Study Design
- Methods
- Controlled experimental study
Abstract
The application of Streptococcus thermophilus S-3 into yogurt production was studied and the structural properties of the generated exopolysaccharides (EPS-S3) were characterized. The proposed structure of EPS-S3 was obtained. EPS-S3 contained a high ratio of N-Acetyl-galactosamine with the Mw of 574 kDa, which was higher than that of AR333 (314 kD) leading to higher apparent viscosity. Streptococcus thermophilus strain S-3 was co-cultured with Lactobacillus delbrueckii for yogut production which highly increased the acidifying rate and post-acidification rate. The quality of the co-cultured yogurts in terms of apparent viscosity, syneresis capacity, water holding capacity and rheological properties were much better than that by using Lactobacillus bulgaricus only. The production mechanism of EPS-S3 from gene regulated level was also discussed which is helpful to facilitate the application of Streptococcus thermophilus strain into milk production.
Keywords: Co-culture; Exopolysaccharides; NMR; Streptococcus thermophilus.