To enhance the extraction yield of pecan protein and modify its functional properties, this study investigated whether both ultrasound and enzyme have a synergistic impact on the extraction of pecan (Carya illinoinensis (Wangenh.) K. Koch) protein. The highest protein extraction rate (25.51%) was obtained under the conditions of 1415.43 W^.cm⁻², 15 min, pH 10.0, 50 °C, and 1% (w/w) alkaline proteinase. Owing to its high shear, mechanical energy and cavitation, the ultrasound process increased the solubility of the substrate making it readily accessible to the enzyme, thereby accelerating the chemical reaction and improving the yield of the protein. The optimized ultrasound-assisted enzymatic method (400 W, 20 kHz, 5 s/3s) effectively changed the secondary and tertiary structure of the pecan protein. The results of surface hydrophobicity, intrinsic fluorescence spectra, sulfhydryl content and scanning electron microscopy all indicated the unfolding of protein and exposure of hydrophobic groups and sulfhydryl groups. Moreover, the protein obtained by this method showed higher solubility (70.77%), higher emulsifying activity (120.56 m²/g), smaller particle size (326.7 nm), and better dispersion (0.305) than single ultrasound and non-ultrasound methods (p < 0.05). To conclude, ultrasound-assisted enzymatic method could be an appropriate technique to improve the yield and quality of the pecan protein. The study also provides a theoretical basis for the application of pecan protein in food processing.

为了提高山核桃蛋白的提取率并改变其功能特性，本研究调查了超声波和酶是否对山核桃（Carya illinoinensis (Wangenh.) K. Koch）蛋白的提取有协同影响。在1415.43 W的条件下获得了最高的蛋白质提取率（25.51%）^。厘米^-2、15 分钟、pH 10.0、50 °C 和 1% (w/w) 碱性蛋白酶。由于其高剪切力、机械能和空化作用，超声过程增加了底物的溶解度，使其易于与酶接触，从而加速化学反应并提高蛋白质的产量。优化的超声辅助酶法（400 W，20 kHz，5 s/3s）有效改变了山核桃蛋白的二级和三级结构。表面疏水性、内在荧光光谱、巯基含量和扫描电镜结果均表明蛋白质的去折叠和疏水基团和巯基基团的暴露。此外，该方法获得的蛋白质具有更高的溶解度（70.77%）、更高的乳化活性（120.56 m ²/g），粒径更小（326.7 nm），分散性更好（0.305）比单超声和非超声方法（p  < 0.05）。总之，超声辅助酶法可能是提高山核桃蛋白产量和质量的合适技术。该研究还为山核桃蛋白在食品加工中的应用提供了理论依据。