Tween20与蛋白质相互作用后对乳液物理及氧化稳定性的影响

Effect of Tween 20 interacting with proteins on the physical andoxidative stability of emulsions

以大豆分离蛋白(soy protein isolate,SPI)和核桃油为主要原料,添加不同浓度的小分子表面活性剂Tween 20,利用高压均质技术制备水包油型(oil in water,O/W)乳液,研究含有蛋白质与小分子表面活性剂混合乳化剂对乳液的界面特性、物理和氧化稳定性的影响。结果表明:当Tween 20质量浓度由0增加到10 g/L时,乳液粒度趋于集中分布,乳滴粒径和微观形态呈现逐渐减小的趋势;Zeta电位的绝对值和表面张力降低;在贮藏期间蛋白质色氨酸荧光强度减弱,氢过氧化物值与硫代巴比妥酸产物值(thiobarbituric acid reactive substances,TBARS)升高。上述结果表明,乳液中Tween 20浓度增加,乳液的物理稳定性得到较好改善,但由于Tween 20取代界面上的SPI,减弱了乳液氧化稳定性。该研究通过分析界面组成对含有混合乳化剂的乳液物理、氧化稳定性的影响,为含小分子表面活性剂的蛋白质乳液在食品加工中的应用提供了参考。

In this experiment,soy protein isolate(SPI)and walnut oil were used as the main raw materials.By adding different concentrations of small-molecule surfactants Tween 20,and preparing the oil-in-water(O/W)emulsion with high-pressure homogenization technology,the effects of emulsifiers containing protein and small-molecule surfactants on interfacial characteristics,physical and oxidative stability of emulsions were investigated.The results show that when the concentration of Tween 20 increases from 0 to 10 g/L,the particle size of the emulsion tends to be concentrated and gradually decreases,and the microstructure of the emulsion also obtains the same results;the Zeta potential and the surface tension decrease;During this period,the tryptophan fluorescence intensity of protein decreases,and the value of hydroperoxide and TBARS increase.The above results indicate that the increase of Tween 20 concentration in the emulsion improves the physical stability of the emulsion;however,the replacement of SPI at the interface by Tween 20 weakens the emulsion oxidation stability.This study of the effects of interfacial composition on the physical and oxidative stability of emulsions containing mixed emulsifiers provides a reference for the application of protein emulsion containing small molecule surfactants in food processing.