高内相乳液包埋玉米黄质及其稳定性研究

Zeaxanthin Encapsulated with High Internal Phase Emulsions and Its Stability

摘要:

【目的】 制备高度稳定的高内相乳液（high internal phase emulsions，HIPEs）包埋玉米黄质，以提高玉米黄质的稳定性，拓展其在食品和医药领域的应用。 【方法】 采用明胶-壳聚糖悬浮液制备HIPEs，用于包埋从枸杞中提取的玉米黄质；利用超高效合相色谱（ultra-performance convergence chromatography，UPCC）分离玉米黄质，通过激光共聚焦扫描显微镜（confocal laser scanning microscope，CLSM）观察乳液结构，根据流变学分析评估乳液的特性，并结合过氧化氢稳定性和贮藏稳定性测试，评估HIPEs包埋对玉米黄质稳定性的改善效果。 【结果】 利用UPCC分离出玉米黄质仅需2.14 min，HIPEs的最优制备条件为：明胶溶液和壳聚糖溶液的质量分数均为0.50%，明胶和壳聚糖的质量比为4∶1，pH为5。CLSM结果显示，利用明胶-壳聚糖悬浮液成功制备了HIPEs。流变学分析的结果显示，负载玉米黄质的HIPEs表现出类固体的弹性行为，其储能模量均高于损耗模量。CLSM结果显示，随着玉米黄质质量分数的增加，负载玉米黄质的HIPEs中油滴聚集且挤压变形，乳液的稳定性逐渐降低。稳定性测试的结果表明，相较于直接溶解于十二烷，HIPEs包埋有效降低了玉米黄质的降解速率，其在过氧化氢处理后的保留率提高了17.98%，在4 ℃贮藏条件下的保留率提升了90.09%。 【结论】 采用明胶-壳聚糖悬浮液制备的HIPEs包埋玉米黄质，可有效改善玉米黄质的稳定性并延长货架期，为解决玉米黄质应用受限问题提供了新思路。

Abstract:

[Objective] This study prepared highly stable high internal phase emulsions (HIPEs) to encapsulate zeaxanthin, thereby improving the stability and expanding the food and pharmaceutical applications of zeaxanthin. [Method] HIPEs were prepared with the gelatin-chitosan suspension for encapsulation of zeaxanthin extracted from goji berries. Ultra-performance convergence chromatography (UPCC) was employed to separate zeaxanthin. Confocal laser scanning microscopy (CLSM) was employed to observe the emulsion structure. The rheological analysis was performed to characterize the emulsion, which was combined with the hydrogen peroxide and storage stability tests to evaluate the performance of encapsulation with HIPEs in improving the stability of zeaxanthin. [Result] The separation of zeaxanthin by UPCC needed only 2.14 min. The optimal preparation conditions for HIPEs were as follows: mass fractions of both gelatin and chitosan solutions were 0.50%, a gelatin-to-chitosan mass ratio of 4∶1, and pH 5. The CLSM results showed that HIPEs were successfully prepared with the gelatin-chitosan suspension. The rheological analysis results showed that HIPEs loaded with zeaxanthin exhibited solid-like elastic behavior, and their storage moduli were higher than loss moduli. The CLSM results showed that with the increase in the mass fraction of zeaxanthin, the oil droplets in zeaxanthin-loaded HIPEs were aggregated, extruded, and deformed, which gradually reduced the stability of the emulsion. The stability test results showed that compared with zeaxanthin directly dissolved in dodecane, the encapsulation in HIPEs effectively reduced the degradation rate of zeaxanthin and increased the retention rate after hydrogen peroxide treatment and storage at 4 ℃ by 17.98% and 90.09%, respectively. [Conclusion] Using HIPEs prepared with the gelatin-chitosan suspension for encapsulation helps to improve the stability and extend the shelf life of zeaxanthin, which provides a new strategy to overcome the limitations of zeaxanthin utilization.