Preparation And Characterization Of Nanocapsules Of Zeaxanthin Extracted From Lycium Barbarum L. By Complex Coacervation

Lycium barbarum L.,a traditional Chinese medicinal and food homologous plant,is rich in flavonoids,betaines,wolfberry polysaccharides,carotenoids and other biologically active substances.Among them,zeaxanthin has attracted much attention because of its effects of enhancing visual function,preventing cardiovascular diseases,and maintaining cognitive function.However,its properties of insolubility in water and unstability limit its application in the food industry.So,it's necessary to explore how to improve the utilization value of zeaxanthin.In this study,by means of complex coacervation reaction between gelatin(G)and sodium carboxymethyl cellulose(CMC),zeaxanthin extracted and purified from Lycium barbarum L.was nanoencapsulated.The main experimental results were as follows:1.The optimal conditions for zeaxanthin extraction were determined as follows: ultrasonic power was 100 W,liquid to solid ratio was 20:1 m L/g,extraction time was 26 min,extraction temperature was 59 ?.The content of zeaxanthin was 2.4839±0.0052 mg/g under this condition.Zeaxanthin had certain antioxidant activity and was sensitive to high temperatures,direct light,acidic environments,metal ions,oxidants,and sour agents.2.The optimum saponification conditions of crude zeaxanthin extract were: 0.15 g/m L of KOH concentration,30 ? of saponification temperature,1.5 h of saponification time,with the saponification rate of 72.98±0.33%.The optimal eluent condition determined by thin layer chromatography was petroleum ether:ethyl acetate(V:V=2:1).Silica gel column chromatography was used to elute the saponified solution and purify the components,the elution band 1 was detected by HPLC as zeaxanthin.3.By examining the charging properties of complex coacervates,it was determined that the optimal wall material ratio was G:CMC=9:1(w/w),and the optimum p H was 4.50.FTIR results showed that the complex coacervation reaction between G and CMC was caused by electrostatic interaction and did not involve the formation of some other chemical bonds.4.Using particle size,polydispersity index(PDI)and Zeta potential as the main indicators,the optimal preparation process of zeaxanthin nanocapsules was determined as follows: core material solvent concentration was 0.5%,zeaxanthin concentration was 15 mg/m L core material solvent,wall material concentration was 0.5%,emulsifier concentration was 0.5%(Tween 80:Span 80=1:1,w/w),and curing agent concentration was 20 U/g gelatin with the embedding rate of 92.60±2.91%.The micrograph showed a regular spherical structure with an average particle size of 210.7 nm,PDI of 0.063,and Zeta potential of-11.5 m V.The results of XRD and TGA showed that the water solubility and thermal stability of zeaxanthin were improved after encapsulating,and a relatively high retention rate was maintained after 28 days of storage.In simulated gastric fluid,zeaxanthin had a good sustained release and in simulated intestinal fluid,zeaxanthin was released in large quantities,and bile salts could promote the release of zeaxanthin.