高场强超声波对大豆分离蛋白溶解性的改善作用

Improving the Solubility of Soybean Protein Isolate by High-Intensity Ultrasound

本研究探讨了高场强超声处理对3%(W/V)和5%(W/V)两种质量体积分数的商业大豆分离蛋白(SPI)溶解性的影响,进而分析其对SPI表面疏水性、粒径和电泳的影响,解析结构变化对溶解性的影响机制。结果表明,200~800 W高场强超声波处理均可显著(p<0.05)提升两种质量浓度商业大豆分离蛋白的溶解性,随超声功率的增大,SPI溶解性呈现先增加后降低的趋势,其中400 W的超声处理3%(W/V)SPI可获得最大的溶解度(47.86%),比对照样品提高了87.4%。除800 W超声处理外,超声处理后3%(W/V)SPI的溶解性均大于5%(W/V)SPI的溶解性。表面疏水性、粒径结果表明,低功率超声处理可使SPI聚集体部分解聚,蛋白表面疏水性下降,粒径降低,溶解性增加;而高功率超声处理可使SPI重新形成不溶性聚集体,致使溶解性下降。电泳结果表明,超声处理没有破坏蛋白亚基结构。结果表明3%(W/V)SPI经400 W的超声处理可获得最优的溶解性改善效果。本研究可为商业大豆分离蛋白溶解性提高提供方法指导。

In this study,the effect of high-intensity ultrasonic treatment on the solubility of the 3%(W/V)and 5%(W/V)commercial soy protein isolate(SPI)was investigated.The effects of high-intensity ultrasonic treatment on the surface hydrophobicity,particle size and electrophoretic mobility of SPI were examined to analyze the mechanism underlying the influence of SPI’s structural changes on its solubility.Results showed that the high-intensity ultrasonic treatment(200~800 W)could improve significantly the solubilities of the commercial SPI products at two mass concentrations.With the increase in ultrasonic power,SPI solubility increased first and then decreased.The ultrasonic treatment at 400 W could lead to the maximum solubility(47.86%),which increased by 87.4% compared to the control.After each of the ultrasonic treatments(except for that at 800 W),the solubility of 3%(W/V)SPI was higher than that of 5%(W/V)SPI.The results of surface hydrophobicity and particle size showed that the low-power ultrasonic treatment could induce partial depolymerization of SPI aggregates,reduce protein’s surface hydrophobicity and particle size thereby increasing solubility of SPI.However,high-power ultrasonic treatment could induce the re-formation of insoluble aggregates,leading to the decrease of SPI solubility.Results of SDS-PAGE showed that the ultrasonic treatment did not destroy the structure of protein subunits.The results showed the optimal improvement of the solubility of the 3%(W/V)SPI obtained by the ultrasonic treatment at 400 W.This work provides guidance for improving the solubility of commercial SPI.