Differences of the Polysaccharides in Kefir Grains from Different Origins Subcultured in Goat Milk

Abstract

Polysaccharides are one of the major building blocks of traditional kefir grains, and their properties are often affected by the geographical origin and substrates used. After subculturing in goat milk for 4 months, spectroscopic, chromatographic, and microscopic imaging techniques were employed for the analysis of the structure of polysaccharides in kefir grains originated from different countries. Fourier transform infrared spectroscopy showed that all polysaccharides were classified into β-d-glucopyranose, and the sugar configuration was β-type. The particle size, molecular weight distributions, and thermal stability of the polysaccharides from kefir grains of CN and DE were apparently higher than those from the USA. The surface structure of polysaccharides in kefir grains of CN and DE was smoother than that of the one from the USA. The results of this study indicated that the molecular and conformational characteristics of polysaccharides were different for kefir grains originated from the three countries when subcultured in goat milk.