紫苏油乳液的制备及其稳定性影响因素研究

本研究针对紫苏油不饱和脂肪酸含量高,在储存过程中易氧化等特点,采用高压均质法制备紫苏油乳液,通过激光粒度仪分析乳液粒径大小与分布,通过TURBISCAN浓缩体系稳定性分析仪监测乳液稳定性的变化趋势,探究乳化剂用量、油水比例、高压均质的压力和循环次数及HLB值对紫苏油乳液稳定性的影响,以提供一种紫苏油缓释方法,拓宽紫苏油在食品中的应用范围。试验结果表明,紫苏油乳液粒径主要分布在300~670nm；乳化剂浓度由0.2%增加至1.2%,乳液粒径下降,稳定性提高；浓度为1.2%时,乳液平均粒径(d=513nm)最小。随着油水比增加,紫苏油乳液稳定性下降；高压均质过程对乳液的稳定性有显著影响,压力越大,循环次数越高,乳液越稳定。与单一乳化剂(HLB=15)相比,复配乳化剂(HLB=8~14)可制得更为稳定的乳液,且当HLB值为11时,紫苏油乳液的平均粒径(d=374nm)最小,乳液稳定性最佳。

Preparation of perilla oil emulsion and factors affecting its stability

Perilla oil-in-water emulsions were produced by high pressure homogenization in this research. In order to observe the effects of emulsifier concentrations, oil-water ratios, homogenization pressures, numbers of homogenization cycle and HLB values on the stability of Perilla oil emulsions, droplet size was analyzed by Zetasizer, emulsion stability was quickly detected through TURBISCAN. Results showed that Perilla oil emulsions had the main droplet size of 300~670 nm, and the stability of emulsions were improved by increasing the emulsifier concentrations from 0.2 % to 1.2 %, Tween80 with a 1.2 % concentration provided the smallest particle size (d=513 nm). The oil-water ratio was negatively correlated with the emulsion stability. High pressure homogenization procedure had significantly effects on the stability of Perilla oil emulsion, the higher the pressure and the more cycle numbers the better. Compared with single emulsifier (HLB=15), compound emulsifier (HLB=8~14) can produce more stable emulsions, and the size of the most stable emulsion was 374 nm, which was the smallest, when the HLB value was 11.