Study On Extraction Of Active Components And Microspheres Preparation Of Pomegranate Peel Extracts

Pomegranate peel which contains polyphenols, flavonoids, polysaccharides andother effective components can exhibit many effects, such as antibacterial,antioxidative, anticancer, and so on. But the pomegranate peel extract was unstableunder high temperature or light, microspheroidization could effectively reduce thedamage degree, was convenient for long-term storage, or further prepared into otherforms. In this paper, extraction process and its influence on polyphenols extraction rateand antimicrobial activity were studied, the preparation technology of pomegranatepeel extract microsphere was investigated by embedding and absorption method.The extraction process of pomegranate peel was optimized by single factor testand central composite design-response surface mothodology. The effect of differentextraction methods, solvents, liquid to solid ratio, ethanol concentration, temperature,time on the extraction rate of polyphenol and antibacterial activity were investigated.The optimum conditions were found as follows: extraction method was ultrasonic,59%ethanol, the liquid to solid ratio40:1, extracted time74min, temperature60℃.The measured value and predictive value for extraction rate of polyphenol andinhibition zone were22.14%、2.80cm and21.88%、2.84cm, respectively, The modelestablished by Central Composite Design could provide better predictability.Chitosan-sodium alginate microsphere of pomegranate peel extract was preparedby embedding method, the encapsulation efficiency was determined by the indicator ofpolyphenol content. The preparation of chitosan-sodium alginate microspheres wasoptimized by single factor test and central composite design-response surfacemothodology, the effect of chitosan solvent pH, drug to material ratio, sodium alginateconcentration, chitosan deposit time, emulsifier concentration, curing time and amountof glutaraldehyde on entrapment efficiency was evaluated. Chitosan solvent pH2,curing time5h, oil-water ratio (mL/mL)3:1, drug to material ratio1:5, sodium alginateconcentration1.09%, chitosan deposit time2.79h, emulsifier concentration19.25%,amount of glutaraldehyde1mL were the optimum preparation conditions. Under theoptimal conditions, the entrapment efficiency was62.23%, there was slight differencebetween the measured value and predicted value which suggested the developed method possessed a good predictability. The prepared microsphere was round, particlesize was uniform, the average particle size was5.978um. The microspheres releaserapidly in gastric juice but slowly in saline. The stability of microspheres wasinvestigated, the results showed prepared microsphere could significantly improve thestability of pomegranate peel extract under high temperature and light conditions.Starch microsphere of pomegranate peel extract was prepared by adsorptionmethod, the encapsulation efficiency was determined by the indicator of polyphenolcontent. The preparation technology of starch microspheres was optimized by singlefactor test and orthogonal design. The effect of dose of crosslinking agent, drug tomaterial ratio, revolution, starch concentration, temperature, emulsifier time, oil-waterratio, emulsifier concentration, curing time on entrapment efficiency was investigated.The optimum preparation conditions were obtained: amount of epichlorohydrin0.12mL， drug to material ratio1:10, stirring speed600r/min, temperature40℃,emulsification time2h, oil-water ratio15:1, emulsifier concentration10%, curing time5h. Under the optimal condition, the mean entrapment efficiency of polyphenol was79.47%. The microspheres was regular, the mean particle size was9.579um. Theprepared microspheres released slowly in both gastric juice and saline. Study on thestability of the microspheres showed, the prepared microsphere could significantlyimprove the stability of pomegranate peel extract under high temperature and lightconditions.In this study, the developed extraction method of pomegranate peel was simple,the extraction rate of polyphenols was high, the extracts exhibited good antibacterialeffect. The microspheres of pomegranate peel extracts was prepared by embeddingmethod and adsorption method, which both exhibited good repeatabilityandcontrollability.