影响核桃油包水乳液物理与氧化稳定性的因素分析

Analysis of Factors Influencing the Physical and Oxidative Stability of Water-in-Walnut Oil Emulsions

以核桃油为油相,以聚甘油聚蓖麻油酸酯（PGPR）为表面活性剂,制备油包水（W/O）乳液,乳液于55 ℃避光保存,每隔1 d测定乳液液滴的平均粒径及粒径分布等物理特性,同时检测乳液初级氧化产物—脂质氢过氧化物与次级氧化产物—己醛,探究水油界面与表明活性剂浓度对W/O乳液稳定性影响。结果表明,在W/O乳液,油水界面存在加速乳液脂质氧化,降低了乳液氧化稳定性。0.3～1.0% PGPR,表面活性剂浓度增大显著降低乳液液滴粒径,提高乳液物理稳定性；同时,表面活性剂浓度增加显著推迟了初级与次级产物形成延迟期,提升了乳液脂质氧化稳定性。W/O体系中过量表面活性剂与脂质氢过氧化物相互作用,增加了脂质氢过氧化物在油相的浓度,并降低了该初级氧化物的分解速率。

Walnut oil was applied to prepare the water-in-oil （W/O） emulsions by employing polyglycerol polyricinoleate （PGPR） as the surfactant and by using microfluidizer. The particle size distributions and mean sizes and the formation of primary oxidation products （lipid hydroperoxides） and secondary oxidation products （headspace hexanal） were examined to evaluate influence of water-oil interface and surfactant on the physical and lipid oxidative stability in W/O emulsions during storage at 55 °C in the dark The results showed that the presence of water-oil interface reduced the oxidative stability of W/O emulsions. Increasing PGPR at the concentrations of 0.3%～1.0% significantly improve the physical and oxidative stability of the emulsions. The interaction of excess surfactant and lipid hydroperoxides increased the partitioning of lipid hydroperoxides into lipid phase, resulting in the reduction in the concentration of lipid hydroperoxides in water-oil interface, and thus the decomposition of lipid hydroperoxides.