紫苏籽油双层乳状液的制备及其物理化学稳定性评价

采用紫苏籽油为芯材，大豆多糖和壳聚糖为壁材，分别制备紫苏籽油单层与双层乳状液，并且对乳状液的粒径、Zeta电位、物理稳定性以及化学稳定性进行评价。结果显示，单层乳状液粒径随着芯壁比（质量比）的升高而增大，物理稳定性变差，最适的芯壁比（质量比）为2∶1；随着壳聚糖质量分数的增加，双层乳状液的Zeta电位逐渐增大，并且由负值变为正值，壳聚糖质量分数为0.2%时电位绝对值最小为3.6 mV，当壳聚糖质量分数为0.4%时电位为43 mV，电位增加速率变小；随着壳聚糖质量分数的增加，乳状液粒径呈先减小、再增大、再减小的变化，壳聚糖质量分数为0.2%时达到最大粒径为5.21 μm，0.4%时达到最小粒径为1.185 μm；随着壳聚糖质量分数的增加乳状液物理稳定逐渐增强。壳聚糖质量分数对乳状液化学稳定性影响显著（p＜0.05），抗氧化效果依次为0.4%＞0.6%＞0.2%。

Preparation and Physicochemical Stability of Perilla Seed Oil Double-Layer Emulsions

In this paper, perilla seed oil single-layer and double-layer emulsions were prepared using perilla seed oil as the core material and soybean polysaccharides and chitosan as the wall material, respectively. The particle size, zeta potential, physical stability and chemical stability of the emulsions were analyzed. Results showed that with the increase in core-to-wall ratio (m/m), the particle size of single-layer emulsions increased and the physical stability became worse and that the optimum core-wall-ratio was 2:1. With the increase in chitosan concentration, the zeta potential of double-layer emulsions increased gradually, changing from negative and positive values. When the chitosan concentration was 0.2%, the minimum absolute value of zeta potential of 3.6 mV was obtained compared to 43 mV when increasing the chitosan concentration to 0.4%, indicating that the rate of increase in potential slowed with increasing chitosan concentration. Moreover, the particle size decreased first, then increased, and finally decreased again. When the chitosan concentration was 0.2%, the maximum particle size of 5.21 μm was observed, and it decreased to the minimum value of 1.185 μm when increasing the chitosan concentration to 0.4%. The physical stability of emulsions increased with the increase in chitosan concentration, and the chemical stability was significantly influenced by chitosan concentration (p < 0.05). The emulsions with 0.4% chitosan had the highest oxidation stability, followed by those with 0.6% and 0.2% chitosan.