不同植物油水包油型乳状液物理特性及氧化稳定性研究

Study on physical properties and oxidation stability of oil-in-water emulsions based on different vegetable oils

以紫苏油、橄榄油、棕榈油和葵花籽油为油相,以乳清分离蛋白为乳化剂,制备水包油(O/W)型乳状液,研究其粒径、ζ-电位、絮凝指数等物理特性,比较不同乳状液在贮存期间的氧化稳定性。结果显示,4种乳状液中,紫苏油乳状液体积平均粒径D_(4,3)较小(0.824μm),ζ-电位绝对值较大(37.5mV),呈现良好的物理贮存稳定性;但由于油脂中有较高的多不饱和脂肪酸,体系易被氧化。棕榈油乳状液具有良好的氧化稳定性,体系初级和次级氧化产物浓度均最低;但乳状液粒径较大(D_(4,3)为1.845μm),物理稳定性较差。通过内源性荧光测定发现,乳状液中蛋白质氧化与脂质氧化存在一定关联性。

In the present study,four types of O/W emulsions were prepared by using perilla oil,olive oil,palm oil and sunflower oil as the oil phase,and whey protein isolate was,as the emulsifier.The physical properties were studied,containing particle size,ζ-potential,flocculation index and others.Meanwhile,the oxidation stabilities of different emulsions in storage were compared.The results showed that among the selected emulsions,perilla oil emulsion showed the smaller volume average diameter D（4,3）（0.824μm）and higherζ-potential absolute value（37.5 mV）,which resulted in a good storage stability.However,due to the perilla oil was mainly composed of polyunsaturated fatty acid,the system was easily oxidized.Palm oil emulsion showed good oxidation stability,namely,the lowest primary and secondary oxidation product concentration.But this emulsion had larger particle size（1.845μm of D（4,3））,and its physical stability was poor.Moreover,it was found that there was a relevance between protein oxidation and lipid oxidation in emulsions through endogenous fluorescence assay.