摘要
以冬虫夏草胞外多糖为研究对象,通过凝胶渗透色谱分析酸水解多糖的分子质量、分子质量降解率(MWDR)和多分散指数(MW/Mn)的变化规律,并在此基础上探讨酸水解动力学。结果表明:酸水解可得到高分子质量和低分子质量两个多糖组分,高分子质量多糖组分的含量、分子质量和MW/Mn均随酸解时间的增加而减小,而MWDR呈线性增加趋势。低分子质量多糖组分含量随酸水解时间的增加而增加,分子质量基本维持在3.0kD;MWDR在0.5h内呈线性增加趋势,大于0.5h后基本维持在0.25。胞外多糖的酸水解模式为中心链断裂,符合假一级反应动力学方程,反应速率常数为3.24×10-2min-1,远小于随机链断裂的反应速率常数。
In this study, exoplysaccharides were isolated from Cordyceps sinensis. Gel permeation chromatography （GPC） was used to determine molecular weight （Mw） and molecular weight distribution of exopolysaccharides subjected to acid hydrolysis. The results showed that high molecular weight fraction （HMWF） and low molecular weight fraction （LMWF） of exopolysaccharides were obtained by acid hydrolysis. The content, Mw and polydispersity index （PDI） of HMWF decreased with increasing reaction time, but the molecular weight degradation ratio （MWDR） showed a linear increase. On the other hand, the content of LMWF increased with increasing reaction time, with mostly a molecular weight of 3.0 kD. The MWDR of LMWF showed a linear increase within the first half an hour of reaction. Afterwards, the MWDR kept constant at about 0.25. Acid hydrolysis of exopolysaccharides was systemetic scission, which followed the pseudo first-order kinetics. The obtained value of rate constant k was 3.24 ×10^-2min^-1, which was much less than that of random scission.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2012年第11期82-85,共4页
Food Science
基金
江苏大学校基金资助项目(105DG129)
广东省高校优秀青年创新人才培育项目(LYM09100)
关键词
冬虫夏草
胞外多糖
酸水解
分子质量
动力学
Cordyceps sinensis
exopolysaccharides
acid hydrolysis
molecular weight
kinetics
