核桃乳酶解工艺及稳定性研究

Study on Enzymatic Hydrolysis Process and Stability of Walnut Milk

摘要:

采用胰蛋白酶对未脱脂的核桃浆液进行酶解，并利用Turbiscan稳定性分析仪对酶解核桃乳的稳定性进行了考察。通过单因素与正交试验优化得到最佳的酶解工艺条件为：核桃浆液浓度9%（m/m）、胰蛋白酶添加量0.4%（m/m）、反应初始pH 9.0、酶解温度55 ℃、酶解时间1 h，在此条件下，蛋白水解度为13.67%±0.41‰。在此基础上，利用Turbiscan稳定性分析仪考察了水解度分别为13.70%、10.20%、7.01%的酶解核桃乳样品与常规工艺样品的稳定性差异。对比背散射光谱图得出，通过酶解工艺产品底部析水层高度由0~10 mm减小至0~5 mm。由底部稳定性动力学指数曲线得到，酶解核桃乳样品稳定性动力学指数均小于对照样品，且水解度较大样品（13.70%）的稳定性指数更小。与常规工艺相比较，酶解核桃乳产品底部TSI曲线均无明显拐点，说明其底部浓度和颗粒粒径的变化幅度小且平缓，稳定性更好。

Abstract:

Walnut milk was hydrolyzed by trypsin, and the stability of the enzymatic prepared walnut milk was studied. The most optimal conditions for enzymatic hydrolysis were as follows: walnut slurry concentration 9% (m/m), trypsin amount 0.4‰ (m/m), pH 9.0, reaction time 1h and temperature 55 ℃. Under these conditions, the degree of hydrolysis (DH) reached 13.67 ± 0.41%. The stability of three hydrolysates with DH of 13.70%, 10.20% and 7.01%compared to the non-hydrolytic process were investigated by Turbiscan. Back scattering curve showed that the height of water separating layer from bottom was reduced from 0~10 mm to 0~5 mm by using the technique of enzymatic hydrolysis. The bottom stability indices of the hydrolysates were lower than the non-hydrolytic sample, and the higher the DH, the lower the stability index. . Compared with the non-hydrolytic process, the stability index curves of the hydrolytic process samples were smoother with unobvious inflection points. All the results indicated that the stability of the enzymatic hydrolysis process was better than the non-hydrolytic process.