蛹虫草多糖的酶法修饰与抗氧化活性

食品科学 ›› 2013, Vol. 34 ›› Issue (1): 114-120.

蛹虫草多糖的酶法修饰与抗氧化活性

贾俊强1,2，沈健3，陈炼3，桂仲争1,2，吴琼英3，张舒3

1.江苏科技大学蚕业研究所 2.中国农业科学院蚕业研究所 3.江苏科技大学生物与化学工程学院

收稿日期:2011-11-14 修回日期:2012-12-18 出版日期:2013-01-15 发布日期:2013-01-07
通讯作者: 贾俊强 E-mail:junqiangjia2008@163.com
基金资助:
江苏省科技支撑计划;江苏省高校科研成果产业化推进拨款项目;江苏省高等学校大学生实践创新训练计划;江苏科技大学本科生创新计划

Enzymatic Modification and Antioxidant Activity of Polysaccharides from Cordyceps militaris Fruit Bodies

Received:2011-11-14 Revised:2012-12-18 Online:2013-01-15 Published:2013-01-07

摘要/Abstract

摘要： 为了提高蛹虫草多糖的抗氧化活性，采用α-淀粉酶对蛹虫草多糖进行酶法修饰。以DPPH自由基清除率为响应值，运用响应面分析法对α-淀粉酶修饰蛹虫草多糖的工艺进行优化，研究酶修饰后蛹虫草多糖清除DPPH自由基、螯合Fe2+和还原力等抗氧化活性，并对其三螺旋体结构进行分析。结果表明：对修饰多糖抗氧化活性的影响因素从大到小依次为：加酶量、酶解温度、酶解pH值；α-淀粉酶修饰蛹虫草多糖的最优工艺条件为：酶解温度48.5℃、酶解pH 5.8、加酶量259.5U/g，在此条件下，酶修饰后蛹虫草多糖对DPPH自由基的清除率预测值为81.4%，验证值为(81.6±1.6)%，结果重现性好，可用于实际预测。抗氧化实验表明，α-淀粉酶法修饰后，蛹虫草多糖清除DPPH自由基和螯合Fe2+的EC50值分别为：0.0247、1.0120mg/mL，分别比酶法修饰前提高了55.1%和39.8%；同时，蛹虫草多糖的还原力也得到了显著提高(P＜0.05)。三螺旋体结构分析表明，蛹虫草多糖经α-淀粉酶修饰后，其三螺旋体结构有轻微破坏，但仍然保持三螺旋体结构。

关键词: 蛹虫草多糖, 酶法修饰, 工艺优化, 抗氧化, 三螺旋体结构

Abstract: Polysaccharides were extracted from Cordyceps militaris fruit bodies and modified using α-amylase for enhanced antioxidant activity. Response surface methodology was employed to optimize conditions for the enzymatic modification of polysaccharides based on DPPH radical scavenging activity. In addition, modified polysaccharides were tested for DPPH radical scavenging activity, ferrous ion chelating capacity and reducing power as well as triple-helical conformation. The optimized hydrolysis parameters were in decreasing order of their effects on DPPH radical scavenging activity of modified polysaccharides: enzyme dosage, temperature and pH and their optimal conditions were 259.5 U/g, 48.5 ℃ and 5.8, respectively. Under these conditions, the maximum predicted and experimental DPPH radical scavenging rates of modified polysaccharides were 81.4% and (81.6 ± 1.6)%. The results of the validation experiments showed good reproducibility and thus, the fitted prediction model is applicable in practice. The antioxidant tests showed that the EC50 values of modified polysaccharides for scavenging DPPH radical and chelating ferrous ions were 0.0247 mg/mL and 1.0120 mg/mL, respectively, which were 55.1% and 39.8% higher than before the modification, respectively. Meanwhile, the reducing power of polysaccharides significantly increased (P＜0.05) after the modification (P＜0.05), and the triple-helical conformation was well maintained but slightly damaged.

Key words: polysaccharides from Cordyceps militaris fruit bodies, enzymatic modification, process optimization, antioxidant activity, triple-helical conformation

中图分类号:

TS201
S886.9

贾俊强1,2，沈?健3，陈?炼3，桂仲争1,2，吴琼英3，张?舒3. 蛹虫草多糖的酶法修饰与抗氧化活性[J]. 食品科学, 2013, 34(1): 114-120.

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