大豆分离蛋白胰酶酶解液对酸乳促发酵作用及增黏作用

Effect of Soy Isolate Protein Hydrolysate by Trypsin on Growth Stimulation and Viscosity Promotion in Yoghurt

为研究大豆分离蛋白胰酶酶解液对酸乳发酵过程中各因素及贮藏过程中黏度的影响,通过监测添加不同水解度的大豆分离蛋白酶解液中肽分子质量和游离氨基酸种类与含量,对酸乳发酵过程中p H值、滴定酸度、嗜热链球菌数和乳酸杆菌数等指标的影响,发现大豆分离蛋白经胰酶酶解24 h后的酶解液对乳酸菌的促生长作用最强,并且能够较快地达到发酵终点,缩短发酵时间。从酶解液肽段和游离氨基酸的分析得出,肽段的分子质量<3 ku对乳酸菌的促发酵作用明显,缬氨酸在促进嗜热链球菌生长的初期最为重要。此外,本试验还考察该酶解液对搅拌型酸乳在贮藏过程中黏度变化的影响,同时与空白样和添加增稠剂的样品进行比较,结果表明,大豆分离蛋白胰酶酶解液能够较好地提高酸乳在储藏过程中的黏度,添加酶解24 h的酶解液对酸乳的增黏作用最强,较空白样提高了近57.219%。

The influence of soy protein isolate（SPI） hydrolysate treated by Trypsin on the process of yoghurt fermentation, added with the distribution of peptide molecular weight and amino acid composition of SPI hydrolysate. During the fermentation process, the viscosity of yoghurt, p H and titratable acidity variation were also studied. Compared different hydrolysate time on the fermentation process, the hydrolysate treated by Trypsin for 24 h stated the highest growthpromoting activity for the strains and the shortest time to the fermentation final. The further analysis on the distribution of peptide molecular weight and amino acid composition of SPI displayed that the peptide molecular which is lower than 3k Da could have an apparent fermentation promoting effect, at the same time, Val is the strongest promoting amino acid in the fermentation process. Meanwhile, the effect of viscosity on yoghurt during storage time was supervised, as well.The result presented that the viscosity of yoghurt was largely improved, especially added with hydrolysate of 24 h, compared with the blank it improved by 57.219%.