酶法制备不同水解度高温豆粕水解产物的理化特性研究

Physicochemical Characteristics of High-temperature Soy Meal Hydrolysates with Different Degrees of Hydrolysis

摘要:

采用Alcalase酶和木瓜蛋白酶分别对高温大豆粕进行酶解，通过控制酶解反应得到水解度为5%、10%和15%的6种水解产物，研究两种酶对不同水解度的水解产物理化特性的影响。结果表明，Alcalase酶和木瓜蛋白酶均可产生6种不同分子量范围的水解产物，但各部分比例具有显著差异（P<0.5），其平均分子量随水解度的增加逐渐减少，Alcalase酶的水解产物中小于2562 Da小分子量肽所占比例更高。豆粕蛋白的疏水基团在酶解反应中发生暴露与断裂的数量差，导致其表面疏水性随水解度增加呈现先下降再上升的变化，即水解度为10%的表面疏水性最低。zeta电势的绝对值随水解度不断上升，分子间的斥力增大，相同水解度下两种酶对zeta电势的影响并不显著。此外，在pH值为3、5、7和9时，水解产物的溶解性随着水解度的增加而逐渐增高，乳化活性和乳化稳定性则逐渐降低。

Abstract:

High-temperature soybean meal was hydrolyzed by Alcalase and papain, respectively. Six kinds of hydrolysates were obtained with the degrees of hydrolysis (DH) of 5%, 10%, and 15%. Effects of Alcalase and papain on physicochemical properties of these different hydrolysates were evaluated. The results showed that Alcalase and papain were all produced six kinds of hydrolysates with different ranges of molecular weight. The proportions of hydrolysates from different enzymes had significant differences (P<0.5), and the average molecular weight of hydrolysates was gradually decreased with increasing the DH. Alcalase included more peptides that less than 2562 Da compared with papain at the same DH. The significant difference of amount between exposed and destruct of hydrophobic groups in enzymatic reactions resulted in surface hydrophobicity decreased firstly with the increasing DH and then increased. Therefore, the hydrolysates with DH of 10% had the minimum surface hydrophobicity than the others. The absolute values of zeta potential increased with increasing DH, and the intermolecular repulsion of molecules increased synchronously. The effect of Alcalase and papain on zeta potential had no significant difference at the same DH. Moreover, at pH 3, 5, 7 and 9, the solubility of the hydrolysates increased gradually with increasing DH, and the emulsifying activity index and emulsion stability index exhibited decreasing trends with increasing DH.