γ-谷维素对淀粉酯-磷脂纳米乳液氧化稳定性的影响机制

Influence mechanism of γ-oryzanol on oxidation stability of nanoemulsionprepared with starch ester and phosphatidylcholine

抗氧化剂的添加能有效提高纳米乳液氧化稳定性。该研究探索γ-谷维素(γ-oryzanol,GO)添加量对以辛烯基琥珀酸淀粉酯(octenyl succinic anhydride modified starch,OSAS)-磷脂(phosphatidylcholine,PC)为乳化剂的纳米乳液性质的影响。结果表明,与未添加GO的纳米乳液(46.12 m V)相比,GO质量浓度为37.5 mg/L的纳米乳液ζ-电位绝对值增加至49.47 m V,所有乳液贮藏4周后未出现分层、絮凝等现象。在25℃贮藏4周的过程中,与未添加GO的纳米乳液相比,含GO的纳米乳液的过氧化值增长较慢,表现出较强的氧化稳定性。分子动力学模拟结果显示,PC-GO(-1.67×10^(5)k J/mol)和甘油三酯(triacylglycerol,TAG)-GO(-1.66×10^(5)k J/mol)的结合能显著低于OSAS-GO的结合能(-1.56×10^(5)k J/mol),表明GO倾向分布于水包油纳米乳液的分散相且靠近界面处。当GO数量由1增至3时,GO与TAG间的结合能由-1.66×10^(5)k J/mol减小至-4.94×10^(5)k J/mol,说明GO的数量影响着其与TAG的结合强度。该研究从实验和理论计算的角度阐明了GO对OSAS-PC纳米乳液的氧化稳定性有着重要影响,有望拓展GO等抗氧化剂提高纳米乳液稳定性方面的基础研究,为开发新式功能乳液产品提供借鉴。

The addition of antioxidants can effectively improve the oxidation stability of nanoemulsion.In this study,the effect ofγ-oryzanol(GO)addition on the properties of nanoemulsions with octenyl succinic anhydride modified starch(OSAS)-phosphatidylcholine(PC)as emulsifiers was investigated.Results showed that the nanoemulsion with 37.5 mg/L GO had a higher absolute value ofζ-potential(49.47 mV)than the nanoemulsion without GO(46.12 mV),and all the nanoemulsions showed physical stability after storage for 4 weeks.The peroxide value of the nanoemulsions containing different GO concentrations increased more slowly than that of the nanoemulsion without GO after storage at 25℃for 4 weeks,showing strong oxidation stability of nanoemulsion containing GO.Molecular dynamics simulation results showed that the binding energy of PC-GO(-1.67×10^(5) kJ/mol)and triacylglycerol(TAG)-GO(-1.66×10^(5) kJ/mol)was significantly lower than that of OSAS-GO(-1.56×10^(5) kJ/mol),indicating that GO tended to be distributed in the dispersion phase of nanoemulsion and close to the oil-water interface.When the number of GO increased from 1 to 3,the binding energy between GO and TAG decreased from-1.66×10^(5) to-4.94×10^(5) kJ/mol,indicating that the number of GO affected its binding strength with TAG.This study illustrated that GO had an important influence on the oxidation stability of nanoemulsion prepared with OSAS and PC from the perspective of the experimental approach and theoretical calculation,which would provide the theoretical guidance of antioxidants including GO improving nanoemulsion stability and some reference for developing new functional emulsion-based products.