库拉索芦荟凝胶黏度及多糖的热稳定性研究

Research on Viscosity and Thermal Stability of Aloe Gel of Barbadensis Mill

测定了库拉索芦荟凝胶不同温度下的黏度,得到了黏度随温度变化的三项式方程:η=at3+bt2+ct+d。对多糖的测定方法进行了改进。在50、60、70、80、90℃下对多糖的热稳定性进行了研究,发现:80～90℃长时间处理,大分子的多糖能发生部分热降解;低温下如50～60℃,由于酶降解作用,大分子的多糖降解速度更快;在70℃下多糖的热稳定性最好,经过70h的热处理,大分子凝胶多糖不仅没有降解成单糖,也没降解成小分子多糖。

The viscosity of aloe gel of barbadensis Mill at different temperatures was measured and the relationship between viscosity and temperature was expressed well by a three-item equation:η=at^3+bt^2+ct+d.The method to analyze polysaccharide concentration using sulphuric acid—phenol was improved.The thermal stability of aloe gel polysaccharide was studied at 50,60,70,80 and 90 ℃.The results show that under the test conditions,at the temperature as high as 80～90 ℃,the aloe gel polysaccharide is partially degraded into lower molecular polysaccharide and a little monose due to thermal lysis,and between 50～60 ℃,as a result of enzymatic lysis,high molecular polysaccharide of aloe gel is largely degraded into lower molecular polysaccharide and monose.70 ℃ is the favorable temperature for aloe gel polysaccharide to exist stably,neither thermal degradation nor enzymatic lysis appears after 70 h.