橄榄油微乳体系的相行为及影响因素研究

本文以大豆卵磷脂和司盘80(Span80)复配为表面活性剂,乙醇为助表面活性剂,构建橄榄油微乳体系。采用拟三元相图法,考察亲水亲油平衡值(HLB值)、表面活性剂与助表面活性剂的比值(Km值)、盐浓度等因素对微乳体系相行为的影响,并通过电导率、负染透射电镜等方法研究微乳体系的结构,以优化体系配方、考察微乳液的形成规律。结果表明:大豆卵磷脂与Span80以质量比为3:1复配为混合表面活性剂,并与助表面活性剂无水乙醇按质量比(Km值)为2:1混合,所形成的大豆卵磷脂/Span80/乙醇/橄榄油/水微乳区域面积最大;甘油或少量盐离子的加入,可以在一定程度上增大微乳单相区的面积,但当盐浓度(C_NaCl)大于4 mol/L时,微乳区域面积明显减小;在大豆卵磷脂/Span80/橄榄油/乙醇/甘油/水微乳体系中,当水相(w_水/w_甘油=1:1)含量大于22 wt%时,体系逐渐由W/O型转变为双连续型结构。当水相含量超过30 wt%,体系则发生相分离。此研究为橄榄油微乳液的制备及应用提供理论和技术支持。

Study on Phase Behavior and Influence Factors of Olive Oil Microemulsion

The food grade olive oil microemulsion system was prepared by using soybean lecithin and span80 as mixed-surfactants,ethanol as a cosurfactant. To optimize the formula and explore the formation rule of the olive oil microemulsion,the effects of many factors on the phase behavior of the olive oil microemulsion were investigated by pseudo ternary phase diagram,such as hydrophilic lipophilic balance(HLB)values,the quality ratios(Km)of the mixed-surfactants and cosurfactant,the addition of chloride sodium and so on. The structural transition of the microemulsion system was determined by conductivity and negative-stained transmission electron microscopy. The results showed that larger single-phase microemulsion region was obtained by mixing soybean lecithin and Span80 as surfactants at a constant weight ratio of 3:1 and keeping the quality ratio of mixed-surfactants and ethanol at 2:1.The addition of glycerol or a small amount of inorganic salt in the aqueous phase could expand the single-phase region of microemulsion system to some extent,while excessive salt ions(C_NaCl>4 mol/L)would decrease the microemulsion region. In soybean lecithin/Span80/olive oil/ethanol/glycerol/water microemulsion system,glycerol was mixed with water as the aqueous phase at a constant weight ratio of 1:1.As the aqueous phase weight content increased beyond 22 wt%,the system gradually transformed into bicontinuous structure from W/O type. The phase separation appeared once the aqueous phase dilution exceeded 30 wt%. Therefore,this study provided theoretical and technical supports for preparation and application of the olive oil microemulsion.