食品科学

• 基础研究 •    下一篇

西藏灵菇发酵乳胞外多糖的流变学特性

陈志娜1,杨希娟2,师俊玲3,*   

  1. 1.西北农林科技大学食品科学与工程学院,陕西 杨凌 712100;2.青海省农林科学院,青海 西宁 810000;3.西北工业大学生命科学学院,陕西 西安 710072
  • 出版日期:2016-03-15 发布日期:2016-03-17

Rheological Properties of Exopolysaccharide Produced by Tibetan Kefir

CHEN Zhina1, YANG Xijuan2, SHI Junling3,*   

  1. 1. College of Food Science and Engineering, Northwest A&F University, Yangling 712100, China;
    2. Qinghai Academy of Agriculture and Forestry Sciences, Xining 810000, China;
    3. School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China
  • Online:2016-03-15 Published:2016-03-17

摘要:

以西藏灵菇发酵乳中分离纯化所得胞外多糖为研究对象,对其流变学特性进行了系统研究。结果表明,该胞外多糖的水溶液表现为典型的非牛顿假塑性流体特性,且其流动行为受胞外多糖的质量浓度、pH值、温度、离子种类和浓度的影响,具体表现为:胞外多糖溶液的黏度随胞外多糖质量浓度的升高而增加,质量浓度越高剪切稀释现象越明显;pH 4.0和pH 10.0时胞外多糖溶液黏度明显低于pH 7.0。Na+可使胞外多糖溶液的黏度显著增大,且Na+浓度越高,溶液黏度越大;Ca2+可使胞外多糖溶液的黏度明显下降,但其下降幅度与Ca2+浓度无关;温度在10~85 ℃范围内胞外多糖溶液的黏度变化很小,有很好的耐温性。加入10 mg/mL的该胞外多糖能够明显增加脱脂乳的黏度。

关键词: 西藏灵菇, 胞外多糖, 流变学特性, 稳态分析, 动态振荡剪切分析

Abstract:

In this study, the rheological properties of exopolysaccharide (EPS) produced by Tibetan kefir were evaluated.
The results showed that the aqueous EPS solution was a typical non-Newtonian pseudoplastic fluid, and its flow behavior
was affected by concentration, pH, temperature, cation type and concentration. Specifically, the viscosity of EPS solution
increased with its increasing concentration and the shear thinning phenomenon was more obvious. The viscosity of
EPS solution at pH 10.0 or pH 4.0 was obviously lower than that at pH 7.0. The addition of Na+ significantly increased
the viscosity of EPS solution in a concentration-dependent fashion. However, the viscosity of EPS solution was greatly
decreased when Ca2+ was added. The viscosity of EPS solution little changed with good temperature resistance at 10–85 ℃.
The viscosity of skim milk was significantly increased by adding 10 mg/mL of the EPS.

Key words: Tibetan kefir, exopolysaccharide, rheological properties, steady-state analysis, dynamic oscillatory shear analysis

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