热处理乳清浓缩蛋白乳化体系储藏稳定性研究

Effect of Preheated Whey Protein Concentrate on the Physical Stability of Oil-in-water Emulsions

主要研究了以预加热的乳清浓缩蛋白(90℃,5 min)为稳定剂的菜籽油水包油型乳状液在储藏期间物理稳定性的变化。测定乳状液在整个储藏期间(0~14 d)的ζ-电势、粒径、絮凝指数、分层指数、流变特性以及蛋白质界面分布指标。研究结果表明,经过预加热的乳清浓缩蛋白相对天然乳清浓缩蛋白能够显著降低乳状液在整个储藏期间的物理稳定性,具体表现为较低的ζ-电势(p<0.05),以及较高的粒径、絮凝指数、分层指数和黏度(p<0.05)。此外,加热导致的乳清浓缩蛋白变性和聚集,能够显著增加其在乳状液界面蛋白膜表面的分布(p<0.05)。上述结果表明,预加热能够显著降低整个乳状液在储藏期间的物理稳定性,为乳清浓缩蛋白的预热处理在乳状液食品中的合理应用提供了理论依据。

The effect of preheated treatment(90 ℃,5 min)on the physical stability of rapeseed oil-in-water emulsion of prepared by using whey protein concentrate as stabilizer were investigated. The changes trend of ζ-potential,particle size,flocculation index,creaming index,rheological property and the partition coefficient of protein in the emulsion during the whole storage period(0-14 days)were measured. The results showed that the preheated treatment of whey protein concentrate could significantly reduce the physical stability of the emulsion during during the whole storage period compared with the natural whey protein concentrate(p < 0.05),especially the lower ζ-potential(p < 0.05),and higher particle size,flocculation index,creaming index and viscosity(p < 0.05). Furthermore,the denaturation and aggregation of whey protein concentrate caused by preheat-treated could significantly increase the distribution of the protein on the surface of the emulsion membrane(p < 0.05),thus confirming the physical stability of the emulsions. The results indicated that the thermal pretreatment significantly reduced the physical stability of the whole emulsion during storage and provided a theoretical basis for the rational application of whey protein concentrate in the emulsion-based food.