酶法制备小麦麸皮膳食纤维及其功能性质的研究

采用酶法提取麦麸中的膳食纤维。研究发现,基于耐高温α-淀粉酶的去除麦麸附着淀粉的条件为:pH6.5,温度96℃,淀粉酶添加量2%,作用时间2h;筛选得到了1种水解麦麸蛋白质能力较强的商业蛋白酶:Alcalase2.4L,此蛋白酶的去除蛋白质的适宜条件为:pH7.5,温度60℃,蛋白酶添加量1.8%,作用时间3.5h,得到的麦麸膳食纤维纯度>90%,室温下用5%H_2O_2脱色3.5h,最终产品纯度为89.89%。对其功能性质进行进一步研究,结果显示,麦麸膳食纤维的持水力、膨胀力、吸油力随产品粒度的减小而减小,阳离子交换能力随粒度的变化不明显。

Extraction of Dietary Fibre from Wheat Bran by Enzymatic Methods and Its Functional Properties

Enzymatic Method was used in this paper to extract dietary fiber form wheat bran.By orthogo- hal tests,the optimal reaction conditions of the extraction were obtained.In step 1,hydrolyze the cohesive starch on wheat bran under the conditions of pH6.5,96℃,heat stableα-amylase enzyme addition 2%,hy- drolyzing time 2h.In step 2,wheat bran protein was hydrolyzed under the conditions of pH7.5,60℃,prote- ase addition 1.8%,hydrolyzing time 3.5h.Alcalase 2.4L was selected as the optimal commercial protease to hydrolyze the wheat bran protein.The purity of dietary fiber was more than 90%,and decreased a little after bleaching 3.5h with 5% H_2O_2.The purity of final product was 89.89%.Some functional properties of wheat bran dietary,such as water holding capacity,water swelling capacity and oil binding capacity were fur- ther studied; the results showed that these functional properties decreased with decrease of particle sizes of the products,whereas exchange capacity didn't noticeably change.