紫山药抗消化淀粉的制备及水解特性*

以酶解-压热法制备紫山药抗消化淀粉,考察了淀粉乳浓度、普鲁兰酶用量、酶解时间、压热时间对制备淀粉中抗消化淀粉含量的影响,通过正交试验和方差分析明确影响因素的重要性并优化工艺条件;比较分析了糊化淀粉、压热淀粉以及酶解-压热法制备淀粉的水解动力学。结果表明:酶解-压热法制备紫山药抗消化淀粉的含量随各因素水平的增加呈先增加后减小的趋势,优化的条件为:淀粉乳质量分数20%、普鲁兰酶用量8 U/g、酶解12 h、以120℃压热处理40 min 2次时,制备抗消化淀粉样品纯度为96.67%,其中抗消化淀粉含量为47.85%;水解特性研究表明:与糊化、压热法相比,酶解-压热法制备抗消化淀粉的水解率、水解指数与血糖指数均显著降低,具有更好的抗消化性。

Preparation of Purple Yam Resistant Starch and its Hydrolysis Properties

The effect of starch concentration, dosage of pullulanase, enzyme digestion time and autoclaving time on the yield of purple yam resistant starch prepared by enzyme-autoclaving method were studied and optimized through orthogonal tests and variance analysis. The hydrolysis kinetics of resistant starch produced by gelatinate, autoclave and enzyme-autoclaving method were compared and analyzed. The results showed that the content of resistant starch increased first and then decreased with the increase of the factor levels. The optimum preparation conditions of purple yam resistant starch were starch concentration of 20%, pullulanase dosage of 8U/g, enzyme digestion time of 12h, two autoclaving-cooling cycles (120°C/40min). Purity, yield of resistant starch were 96.67% and 47.85%, respectively. Hydrolysis properties experiments showed that the hydrolysis rate, hydrolysis index and estimated glycemic index of resistant starch prepared by enzyme-autoclaving method significantly decreased and had better digestion resistibil ity compared to gelatinized and autoclaved starches.