高、低酰基结冷胶的乳化活性及稳定性

Emulsifying Activity and Emulsion Stability of High and Low Acyl Gellan Gum

以高酰基结冷胶(HA)、低酰基结冷胶(LA)为乳化剂,以中链甘油酸酯(MCT)为油相,通过超声乳化法制备水包油(O/W)乳液。以阿拉伯胶(GA)为对照,考察添加不同浓度、类型结冷胶条件下乳液的外观变化、界面张力、Zeta-电位和粒径分布等,比较高、低酰基结冷胶的乳化特性。研究结果表明,以HA为乳化剂制备的O/W乳液平均粒径略大于以GA制备的乳液,而LA乳液粒径最大;HA乳液-电位绝对值整体显著大于GA乳液(P<0.05),且在最优浓度条件下HA乳液界面张力小于GA乳液,因此HA乳液乳化稳定性优于GA乳液。而LA乳液ζ-电位绝对值最小,界面张力最大,其乳液稳定性最差。储藏试验表明,HA乳液稳定性高于GA乳液,且在60℃储藏条件下的粒径变化率显著小于GA乳液。LA乳液极不稳定,制备当天即出现分层现象。本文着重研究不同酰基结冷胶在乳化性能方面的应用差异,结果为高酰基结冷胶具有良好的乳化活性和稳定性。此结果对高酰基结冷胶的品质提升和应用推广等方面具有重要的意义。

Oil-in-water(O/W)emulsion was prepared by ultrasonic emulsification with high acyl gellan gum(HA)and low acyl gellan gum(LA)as emulsifiers and medium-chain triglyceride(MCT)as oil phase.Compared with Arabic gum(GA),the emulsifying properties of high and low acyl gellan gum were compared.The appearance change,interfacial tension,Zeta-potential and particle size distribution of emulsion with different concentrations and types of gellan gum were investigated.The results showed that the average particle size of O/W emulsion prepared with HA as emulsifier was slightly larger than that prepared with GA,while the particle size of LA emulsion was the largest.The absolute value of Zeta-potential of HA emulsion was significantly larger than GA emulsion(P<0.05),and the interfacial tension of HA emulsion was smaller than GA emulsion under the optimal concentration condition,so the emulsifying stability of HA emulsion was better than GA emulsion.LA emulsion has the smallest absolute value of Zeta-potential,the largest interfacial tension,and the worst emulsion stability.The storage test showed that the stability of HA emulsion was higher than GA emulsion,and the particle size change rate at 60℃was significantly lower than GA emulsion.LA emulsion is extremely unstable,and stratification occurs on the day of preparation.In this paper,the application differences of different acyl gellan gum in emulsifying properties were studied.The results showed that high acyl gellan gum had good emulsifying activity and stability,which provided important significance for the quality improvement and application promotion.