生姜中分离得到具有凝乳活力的生姜蛋白酶,研究了动态升温模式下制作生姜蛋白酶凝乳的工艺条件及其在冷藏过程中的物理化学变化。主要结果如下:在低pH下脱脂乳凝胶的三维网状结构具有较大的孔隙,酪蛋白基质的分布比较稀疏,副酪蛋白微粒间形成稠密的交叉连接,孔隙的尺寸较小。随着温度的升高,脱脂乳的微观结构逐渐形成紧缩的状态。脱脂乳凝胶在冷藏过程中凝胶强度、乳清析出和α-氨基氮含量没有显著变化,酪蛋白没有显著的水解,表明动态升温模式能够达到抑制生姜蛋白酶的蛋白水解活力,使凝胶产品在冷藏期间保持稳定。

Worldwide,plant chymosin development for substitution of calf rennet has always been the hot topic of dairy science. Ginger protease with milk coagulating activity was isolated from ginger root. The processing conditions at a dynamic heating pattern for making skim milk gel and its physicochemical variation during cold storage were assayed. The results showed that large pores were formed in the three dimensional network of skim milk gel at low pH value and thus showed a thinner casein matrix. Dense cross-linkage between casein micelles and small pore size were observed in skim milk gel made at natural pH. As the temperature raised,the microstructure of skim milk gel showed a gradual contraction. The gel strength,syneresis,and α-amino nitrogen content kept stable during cold storage of the skim milk gel. The casein underwent no significant proteolysis. Dynamic heating pattern was suggested to be an effective processing condition to inhibit the proteolytic activity of ginger protease and keep the milk gel stable during cold storage.