碱性pH偏移结合超声处理对花生蛋白结构与功能性质的影响

    Effect of alkaline pH shift combined with sonication on the structural and functional properties of peanut protein

    • 摘要: 为了改善花生蛋白的功能性质,采用碱性pH偏移(pH12和pH13)单独或结合超声(500 W/5 min和30 min)处理花生蛋白,研究了处理前后花生蛋白结构、功能以及赖丙氨酸含量的变化规律。结果表明:所有处理方式均能提高花生蛋白的表面疏水性并使其内源荧光最大发射波长发生红移,其中pH12偏移结合长时间超声处理、pH13单独偏移或结合超声处理还能使花生蛋白可溶性聚集体含量显著增加,二级结构中α-螺旋减少、β-转角增加;pH12或pH13单独偏移均显著增加了花生蛋白中赖丙氨酸含量,而与超声结合处理后可使赖丙氨酸含量降低60%~66%。所有处理方式均能改善花生蛋白的溶解性和乳化性,其中pH13偏移结合短时间超声处理使花生蛋白溶解度提高了19%,乳化活性和乳化稳定性指数分别增加了56%和271%,乳液的冻融稳定性显著增强。pH13偏移结合超声处理不仅能显著提升花生蛋白的功能性质,而且可以有效抑制赖丙氨酸的产生,因此是一项应用潜力较高的蛋白复合改性技术。

       

      Abstract: In order to improve the functional properties of peanut protein, alkaline pH shift (pH12 and pH13) was used to treat peanut protein alone or in combination with ultrasound (500 W/5 min and 30 min), and the changes of peanut protein structure, function and lysalanine content before and after treatment were studied. The results showed that all treatments could improve the surface hydrophobicity of peanut protein and red-shift the maximum emission wavelength of endogenous fluorescence. Among them, pH12 offset combined with long-term ultrasonic treatment, pH13 offset alone or combined with ultrasonic treatment could also significantly increase the content of soluble aggregates of peanut protein, reduce α-helix and increase β-turn in the secondary structure. Shifts of pH12 or pH13 alone significantly increased the content of lysine in peanut protein, while the combination of ultrasonic treatment could reduce the content of lysine by 60-66%. The solubility and emulsification of peanut protein were improved by pH13 offset combined with low-intensity ultrasonic treatment, and the solubility of peanut protein was increased by 19%, the emulsifying activity and emulsion stability index were increased by 56% and 271%, respectively, and the freeze-thaw stability of the emulsion was significantly enhanced. pH13 offset combined with ultrasonic treatment can not only significantly improve the functional properties of peanut protein, but also effectively inhibit the production of lysalanine, so it is a protein complex modification technology with high application potential.

       

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