Preparation Of Microcapsules Of Essential Oil Of Litsea Cubeba And Its Freshness Preservation Application

This study investigates the preparation method of microencapsulated Litsea cubeba essential oil and its application in citrus preservation.Litsea cubeba essential oil,as a naturally volatile plant oil,possesses a wide range of biological activities.However,its application is limited due to its volatility and strong odor.To overcome these limitations,researchers have employed microencapsulation technology to encapsulate the essential oil,which not only mitigates its drawbacks but also allows for the modulation of its sustained release properties.In this study,β-cyclodextrin(β-CD)and soy protein isolate(SPI)were selected as composite wall materials,while Litsea cubeba essential oil served as the core material.The microcapsules containing Litsea cubeba essential oil were prepared using the spray drying method,and the process conditions were optimized.The microcapsules were characterized using scanning electron microscopy(SEM),laser particle size analyzer,Fourier-transform infrared spectroscop and dynamic stability control DSC to analyze their physicochemical and thermal properties.Moreover,the preservation effect of the Litsea cubeba essential oil microcapsule film on citrus fruits was evaluated through measurements of weight loss rate,decay rate,titratable acidity,soluble solids,hardness,and chromaticity analysis.Specifically,the following aspects were examined:(1)Preparation and Process Optimization of Microcapsules Containing Litsea cubeba essential oilMicrocapsules containing Litsea cubeba essential oil were prepared and optimized using β-cyclodextrin-soy protein isolate as composite wall materials through spray drying technique.The effects of wall material ratio(w/w),core-to-wall ratio(w/w),feed temperature,and solid content on encapsulation efficiency were investigated through single-factor experiments and response surface experiments.The optimal preparation conditions for the microcapsules were determined as follows: β-CD-SPI ratio of 1:1,core-to-wall ratio of 0.27,solid content of 12.68%,and feed temperature of 210°C.Under these conditions,the encapsulation efficiency of the microcapsules reached 73.32%.(2)Performance characterization of Microencapsulated Litsea cubeba essential oilThe physicochemical properties,structural characteristics,and thermal stability of the microencapsules were analyzed using SEM,particle size analyzer,FT-IR,X-RD and DSC.The storage stability of the microencapsules at different temperatures was also studied.The results showed that the microencapsulated Litsea cubeba essential oil was a creamy white powder with a smooth surface and a lemon fragrance.The average particle size was 32.04μm,and the moisture content of the microencapsulated Litsea cubeba essential oil was6.85%.The FT-IR and X-RD results indicated successful encapsulation of the Litsea cubeba essential oil within the wall material,using β-cyclodextrin-soy protein isolate,which helped preserve the properties of the Litsea cubeba essential oil.(3)Preservation Effect of Microcapsules Containing Litsea cubeba essential oil on Citrus FruitsThe coating solution containing microcapsules containing Litsea cubeba essential oil was applied to preserve citrus fruits,and the effects of the coating solution on hardness,titratable acidity,soluble solids,color,and weight loss rate during the storage of citrus fruits were investigated.The results demonstrated significant effects of the microcapsule coating in all aspects mentioned above.Overall,the microcapsule coating extended the postharvest storage period of citrus fruits and maintained their quality.