分步酶解小麦面筋蛋白制备低苦味肽粉的研究

目的 研究分步酶解小麦面筋蛋白(wheat gluten, WG)制备低苦味肽粉的工艺。方法 选用中性蛋白酶、木瓜蛋白酶、胃蛋白酶水解WG至8%水解度，接着用风味蛋白酶对水解产物进行脱苦处理，对不同酶解产物中苦味肽的特性进行系统研究，探究苦味肽含量、氨基酸组成、分子量分布、表面疏水性等指标变化对WG酶解物苦味值的影响，对比风味蛋白酶对不同单酶酶解物的脱苦效果差异，分析风味蛋白酶对WG酶解物脱苦的内在机理，进而确定制备低苦味小麦蛋白肽粉的最佳酶解工艺。结果 中性蛋白酶的酶解产物经风味蛋白酶作用后，脱苦效果最显著，苦味肽苦味值从4.08降至2.25，酶解产物的苦味值可下降56.42%。木瓜蛋白酶的酶解产物经风味蛋白酶作用4 h后，酶解产物的苦味值最低，制备出苦味值为1.28的WG低苦味肽粉。结论 经分步酶解作用后，酶解产物中苦味肽的含量下降；疏水性氨基酸比例的下降和游离氨基酸含量的升高引起苦味肽苦味阈值的增大，共同导致酶解产物苦味值显著降低，该研究为酶解脱苦技术的快速发展和WG活性肽工业化生产提供新的参考。

Study on the preparation of low bitter peptide powder by stepwise enzymatic hydrolysis of wheat gluten protein

Objective To study the process of preparing low bitter peptide powder by stepwise enzymatic hydrolysis of WG. Methods Neutral protease, papain and pepsin were used to hydrolyze WG to 8% degree of hydrolysis, and then the hydrolysate was debitterized by flavor protease. The characteristics of bitter peptides in different hydrolysates were systematically studied. The effects of bitter peptide content, amino acid composition, molecular weight distribution, surface hydrophobicity and other indicators on the bitterness value of WG hydrolysates were investigated. The difference of debittering effect of flavor protease on different single-enzyme hydrolysates was compared. The internal mechanism of debittering of WG hydrolysates by flavor protease was analyzed, and the best enzymatic hydrolysis process for preparing low bitter WG peptide powder was determined. Results After the enzymatic hydrolysate of neutral protease was treated by flavor protease, the debittering effect was the most significant. The bitterness value of bitter peptide decreased from 4.08 to 2.25, and the bitterness value of enzymatic hydrolysate decreased by 56.42%. The bitterness value of the enzymatic hydrolysate of papain was the lowest after 4 h of action by flavourzyme, and the low bitterness peptide powder of WG with bitterness value of 1.28 was prepared. Conclusion After step-by-step enzymatic hydrolysis, the content of bitter peptides in the enzymatic hydrolysate decreases. The decrease in the proportion of hydrophobic amino acids and the increase in the content of free amino acids cause an increase in the bitterness threshold of bitter peptides, which together lead to a significant decrease in the bitterness value of enzymatic hydrolysates. This study provides a new reference for the rapid development of enzymatic debittering technology and the industrial production of WG active peptides.