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The effect of litchi juice on exopolysaccharide production in milk fermented by Lactobacillus casei
Author(s) -
Yu Yuanshan,
Wu Jijun,
Xu Yujuan,
Xiao Gengsheng,
Zou Bo
Publication year - 2018
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.13884
Subject(s) - fermentation , food science , lactobacillus casei , chemistry , sugar , monosaccharide , lactobacillus , fermented milk products , lactic acid , bacteria , biochemistry , biology , genetics
Summary In this paper, Lactobacillus casei growth, sugar utilisation, exopolysaccharides ( EPS s) formation and EPS s characterisation during fermentation of milk with or without litchi juice were evaluated. During L. casei fermentation of litchi‐milk samples, the EPS s content increased with the increase of litchi juice levels (0–25%, v/v), and the both relationship appeared in S ‐type curve. The viscosity of fermented milk also significantly increased with the formation of EPS s, and which positively correlated with the EPS s content ( R 2 = 0.9782). The EPS s from the fermented litchi‐milk samples was isolated for further structural characterisation. Monosaccharide and molecular weight analysis of purified EPS s sample proved that it contained no carbohydrate other than glucose, and its molecular weight was calibrated as 3.03 × 10 6 Da. FT ‐ IR and NMR ( 1 H and 13 C) spectroscopy analysis confirmed the synthesised EPS s sample was α‐glucans (dextrans) with mainly α‐(1→6) linkages. To the best of our knowledge, this is the first study to report that litchi juice can enhance the EPS s (dextrans, mainly α‐(1→6) linkages) production in fermented milk.