Abstract: Peanut protein’s application in acidic beverage is limited due to its reduced solubility and flocculation under acidic conditions. In this study, a combination of high-pressure homogenization and neutral proteolysis was used to improve the solubility of peanut protein at pH 4.0. The effect of different concentrations of modified protein addition on the stability of juice were analyzed according to the Turbiscan backscattering coefficient value and Turbiscan instability index (TSI). The optimal process obtained by response surface analysis was: homogeneous pressure 79.74 MPa, ratio of material to liquid 7.23%, enzyme addition amount 517 U·g^-1, and enzymatic hydrolysis time 48.20 min. The nitrogen solubility index (NSI) of modified peanut protein at pH 4.0 increased from 4.04% to 37.49%. The modified peanut protein was added to orange juice at pH 3.88, and the stability index TSI of fruit juice with 3% and 4% modified protein addition was 1.95 and 2.23, respectively, which was significantly better than those with 5% protein added samples (TSI 3.29). These results showed that high-pressure homogenization and neutral proteolysis compound modification could significantly improve the solubility of peanut protein at pH 4.0, and the modified protein had good stability in acidic beverages, which provided a reference for the application of plant protein in acid beverages.

Key words: peanut protein, acidic beverage, compound modification, solubility, stability

摘要： 花生蛋白在酸性条件下会絮凝沉淀,溶解性降低,限制了其在酸性饮料加工领域的应用。本研究通过利用高压均质-中性蛋白酶酶解复合改性提高花生蛋白在pH值4.0条件下的溶解度,并根据Turbiscan多重光散射稳定性分析仪的背散射光强值和体系不稳定指数(TSI)分析不同浓度改性蛋白添加量对酸性果汁稳定性的影响。响应面分析结果表明,高压均质-中性蛋白酶酶解复合改性的最优工艺为:均质压力79.74 MPa,料液比7.23%,加酶量517 U·g^-1,酶解时间48.20 min,此时,花生蛋白在pH值4.0条件下氮溶指数(NSI)从由4.04%提升至37.49%。将改性后蛋白加入pH值3.88的果汁中,改性后蛋白添加量为3%和4%的果汁稳定性指数(TSI)分别为1.95和2.23,显著优于蛋白质添加量为5%的样品(TSI为3.29)。研究表明高压均质-中性蛋白酶酶解改性可以显著提高花生蛋白在pH值4.0条件下的溶解度且改性后蛋白在酸性饮料中稳定性良好,为植物蛋白在酸性饮料中的应用提供了参考。

关键词: 花生蛋白, 酸性饮料, 复合改性, 溶解性, 稳定性