Studies on the Preliminary Characterization of a Novel Exopolysaccharide Produced by Streptococcus Thermophilus Ttrain from Tibetan Kefir Grain
The novel exopolysaccharide (EPS) was produced by a streptococcus thermophilus strain isolated from Tibetan kefir grain, and it was purified using DEAE cellulose 52 and DEAE Sepharose CL-6B column chromatography. It was eluted as a single symmetrical narrow peak on high-performance gel-permeation chromatography (HPGPC) and the average molecular weight was estimated to be 30,092Da. Infrared spectrum analysis indicated that its main absorptions are characteristic of glycosidic structures. Gas chromatography showed that the EPS is composed of mannose and glucose in a molar ratio of 2.6:1 with trace galactose. The structural features of EPS were investigated by partial hydrolysis with acid, methylation analysis and NMR spectroscopy analysis. The results revealed that the main backbone chain of EPS was (2→3)-β-D-Manp, (3→4)-β-D-Manp, (2→3,6)-α-DGlcp and trace amounts of galactose.
exopolysaccharides Streptococcus thermophilus Tibetan kefir grain structural characterization
Shu-juan Jiang Xiaohui Ren Guangqing Mu Fang Qian
School of Food Engineering Dalian Polytechnic University Dalian, China
国际会议
哈尔滨
英文
829-832
2012-06-16（万方平台首次上网日期，不代表论文的发表时间）