| Zeaxanthin has the physiological function of preventing age-related macular degeneration,retinal degeneration and other eye diseases as well as filtering harmful blue light,and is often used as a dietary supplement.Zeaxanthin is easily oxidized in the air,so it is important to study the methods to improve its stability.High internal phase emulsions（HIPEs）have that characteristics of high stability,green safety and the like,and have practical application in the field of encapsulate active substances such as beta-carotene and the like.In order to improve the stability and biological activity of zeaxanthin,a method of encapsulating zeaxanthin with highly stable HIPEs was established in this paper,which took the dried fruit of Lycium barbarum L.as the research material,and provided a reference for the selection and application of embedding materials of sensitive bioactive substances.The main research contents are as follows:（1）Extraction and identification of zeaxanthin from dried fruit of Lycium barbarum L.The optimum extraction conditions were as follows:n-hexane-absolute alcohol(1:1,v·v-1),extraction time 3 h,extraction temperature 60℃and the ratio of material to solvent 1:10(g·m L-1).Zeaxanthin was qualitatively analyzed by liquid chromatography-mass spectrometry and separated by UPCC at 2.14 min.（2）Preparation and optimization of HIPEs.HIPEs were prepared by high-speed homogenization of an aqueous phase crosslinked by transglutaminase（TG）and an oil phase.The effects of GE/CS concentration,mass ratio and p H value on the macrostructure,microstructure and rheological properties of gelatin/chitosan（GE/CS）emulsion were investigated.The optimal preparation conditions of initial HIPEs were as follows:the mass ratio of GE and CS was 4:1,p H was 5,and the same concentration of GE and CS was 0.5 wt%.Under these conditions,HIPEs had high viscosity and high elasticity rheological behavior.The HIPEs were oil-in-water emulsion system by confocal laser scanning microscopy.Compared with the initial HIPEs,the size of oil droplets in the emulsion prepared by TG cross-linking GE/CS was smaller,the intersection of storage modulus and loss modulus appeared later,and no water layer was separated out after high temperature treatment,which indicated that TG had a positive effect on improving the stability of HIPEs and provided a stable embedding material for subsequent encapsulation of zeaxanthin.（3）The properties,stability and in vitro simulated digestion characteristics of zeaxanthin encapsulated in HIPEs were studied.The content of zeaxanthin can affect the properties of the emulsion.The results of laser scanning confocal microscopy and rheology showed that the emulsion with 0.08%zeaxanthin had a strong gel network structure,and the stability of the emulsion decreased to the lowest with the increase of zeaxanthin content to 0.16%.Scanning electron microscopy（SEM）results showed that the surface structure of the emulsion was porous network structure.Encapsulation of HIPEs could improve the storage stability of zeaxanthin.The retention rate of zeaxanthin increased by 12.07%after hydrogen peroxide interference for 8 h,by 28.82%and 17.73%after storage at 4℃and 25℃for 21 d in dark,and by 19.92%after storage at light for 21 d.In vitro simulated gastrointestinal digestion test found that the release of free fatty acids increased steadily,zeaxanthin was slowly and stably released after encapsulation,and the retention rate of zeaxanthin was 76.60%,which was 14.27%higher than that of the control group（62.33%）,indicating that the encapsulation of HIPEs enhanced the stability and bioactivity of zeaxanthin,which provided reference information for the development of functional foods containing zeaxanthin formula. |
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