为了提高大豆分离蛋白(SPI)的起泡性,对SPI经alcalase有限水解产物中不同分子大小的肽段采用谷氨酰胺转移酶TGase进行交联。结果表明:TGase交联可有效提高SPI的起泡性,特别是显著地提高了其泡沫稳定性;MW﹥10 ku的大分子肽当加酶量为15 U/g底物且交联4 h时得到最佳的泡沫稳定性为88.5%;MW﹥10ku和MW﹤5 ku的大分子和小分子肽混合物当加酶量为50U/g(底物),交联时间为4 h、大分子与小分子肽摩尔比为1∶1时得到的最佳泡沫稳定性为60.3%;MW>10 ku的大分子肽交联产物的分子质量显著高于MW>10ku的大分子肽和MW<5 ku的小分子肽(摩尔比1∶1)交联产物的分子质量。

In order to improve the foaming properties of soy protein isolate(SPI),transglutaminase(TGase) cross-linking was employed for the large(MW﹥10 ku) and small molecular peptides(MW﹤5 ku) that hydrolyzed from SPI with alcalase.The results demonstrated that: TGase cross-linking could effectively improve the foaming property of SPI,especially improve the foam stability effectively;for the large molecular peptide(MW﹥10 ku),the optimum foam stability(88.5%) was obtained with 15 U/g substrate of enzyme and 4 h of cross-linking time;as for the mixture of large molecular peptide(MW﹥10 ku) and small molecular peptide(MW﹥5 ku),the optimum foam stability(60.3%) could be obtained by 50 U/g substrate of enzyme,4 h of cross-linking time with 1∶ 1 molar ratio of large and small molecular peptide;the molecular weight of the cross-linking products from large molecular peptide(MW﹥10 ku) was higher than that from the mixture of large(MW﹥10 ku) and small(MW﹤5 ku) molecular peptide.The research may provide certain theoretical basis for improving the foaming property of SPI by enzymatic method.