ABSTRACT This research investigated the enzymolysis kinetics of high-intensity ultrasound (HIU)-assisted alkali pretreatment Ovalbumin (OVA) through using Alcalase, and its structural and functional properties. The structural characteristics of OVA were performed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), surface hydrophobicity, Fourier Transform Infrared, and differential scanning calorimetry. SDS-PAGE analysis indicated that the pretreatment sample showed proportion of lower molecular mass components (14.3–20.1 kDa). There was an increase in the intensity of fluorescence spectrum and changes in functional groups after the pretreatment on OVA compared with the control (without treatment), which might be the reason for the significantly enhancing efficiency of the enzymatic hydrolysis. The thermal denaturation temperature of enzymatic hydrolysis of OVA after pretreatment was 95.1°C, which was 17.5°C higher than that of control. As compared to OVA (control), the enzymatic hydrolysis with HIU-assisted alkali pretreatment was found to significantly improve protein solubility, emulsifying properties, foaming ability (FA) and foam stability, oil, and water absorption capacity (WAC). Especially emulsifying activity index, FA, WAC, and oil absorption capacity were increased by 228.7%, 88.5%, 102.6%, and 67.4%, respectively (P< 0.05). A simplified kinetic equation for the enzymolysis model was deduced to successfully describe the enzymatic hydrolysis of pretreated OVA. The results proved the effects of the pretreatment on the substrate enhanced the enzymolysis process and this influence had relation to the structure changes. Furthermore, the enzymatic hydrolysis process for other proteins demonstrated the applicability of the model.

中文翻译：

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高强度超声辅助碱预处理卵清蛋白的酶解动力学和结构功能特性

摘要 本研究通过使用 Alcalase 研究了高强度超声 (HIU) 辅助碱预处理卵清蛋白 (OVA) 的酶解动力学及其结构和功能特性。OVA的结构特征通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）、表面疏水性、傅里叶变换红外和差示扫描量热法进行。SDS-PAGE 分析表明，预处理样品显示出较低分子量组分（14.3-20.1 kDa）的比例。与对照（未处理）相比，OVA预处理后荧光光谱强度增加，官能团发生变化，这可能是酶水解效率显着提高的原因。预处理后OVA酶解热变性温度为95.1℃，比对照高17.5℃。与 OVA（对照）相比，HIU 辅助碱预处理的酶水解被发现显着提高了蛋白质溶解度、乳化性能、发泡能力 (FA) 和泡沫稳定性、吸油和吸水能力 (WAC)。特别是乳化活性指数、FA、WAC和吸油量分别提高了228.7%、88.5%、102.6%和67.4%（P<0.05）。推导出酶解模型的简化动力学方程，以成功描述预处理 OVA 的酶水解。结果证明预处理对底物的影响增强了酶解过程，这种影响与结构变化有关。