Extraction And Microencapsulation Of Perilla Essential Oil

Perilla is a kind of annual herbaceous plant,and there are abundant perilla resources in China.The effective substances extracted from perilla leaves have a broad market space in the pharmaceutical,food and cosmetic industries.In this paper,the extraction,chemical composition,microencapsulation of the essential oil from perilla leaves and its application in strawberry preservation were studied,these results provided theoretical basis and technical support for the development and utilization of natural preservatives.The main findings are as follows:(1)The extraction rate of perilla essential oil was between 0.32% and 1.76%,and the highest extraction rate was 1.76% from the cultivar XL.Therefore,the leaves of XL collected in the seedling stage was recommended to as the best material for extracting perilla essential oil.Twenty-three natural chemicals including alkenes,ketones,alcohols,aromatic and heterocyclic compounds were identified by GC-MS analysis,some of them were main composition and had higher contents,such as 2-hexanoylfuran(23.51%-80.25%),1-(3-Methyl-2-furanyl)-3-methyl-2-buten-1-one(0.27%-9.03%),1-methyl-2-methyl-2-methyl benzene(1.8%-51.5%),caryophyllene(2.08%-5.63%)and trans-Bergsmotene(0.2%-6.78%).(2)Gum arabic,symplectic alkenyl succinic acid starch ester and beta cyclodextrin were selected as wall materials to preparing the perilla essential oil microcapsule powder by two methods,freeze drying and spray drying respectively.The embedding rate and the bacteriostatic activities of all treatments were determined,and the results showed that it was the best suitable for alkenyl succinic acid starch ester as wall material,and the embedding effect of spray drying was better than that of freeze-drying.(3)The embedding effect of process conditions on perilla essential oil powder was studied.On the basis of single factor experiment,essential oil purity,wall contents,and the ratio of wall as main factors,the microcapsule powder preparation technology was optimized by using the Box-Behnken central composite design and response surface method.The studyestablished the forecast model of the quadratic polynomial regression equation,and the optimum preparation conditions was: perilla essential oil purity 81%,wall material content20%,the ratio of wall to core 3:1.The embedding rate can reach 80.46% under these conditions.(4)The stability of perilla essential oil was improved by the treatment of microencapsulation.In terms of morphology,the microcapsule powder presented a spherical shape with shallow depression.Infrared spectrum characterization and thermogravimetric analysis showed that microencapsulation of perilla essential oil was simple physical coating process and made its stability improved.The release rates of essential oil of microcapsule powder at different storage temperature were detected,indicates that lower temperature can effectively reduce its volatility.Therefore,microencapsulation improves the stability of Perilla essential oil.(5)Strawberry preservation application research showed that perilla essential oil microcapsule powder can effectively delay the loss rate of strawberry nutrients such as total phenol,titratable acid,vitamin C and soluble solids,reduce the weightlessness rate,pH value,the total number of colonies and decay rate,keep the strawberry sensory quality and improve nutritional quality greatly.