Study On Extraction And Activity Of Essential Oils Of Three Kinds Of Citrus

Citrus(Citrus reticulata Blanco)belongs to the genus of Rutaceae.The production of citrus in China and even the world is very rich,and the resources of citrus essential oil are gradually enriched.Citrus essential oil not only has a pleasant aroma,but the essential oil itself also has many biological activities.This project takes Zhejiang Jinhua bergamot,Jiangsu Jinjiang citron and Jiangxi Jiangxi navel orange as the research objects,and further studies the relationship between the composition and biological activity of these essential oils to develop and expand the application value of citrus essential oils in the fields of daily chemicals and food.Firstly,we studied the extraction of golden bergamot essential oil,citron essential oil,and Gannan navel orange essential oil through squeezing method and steam distillation method.The composition differences of the six essential oils were analyzed and compared by GC-MS.Then,response surface methodology(RSM)was used to optimize the extraction process for extracting essential oil from Gannan navel orange.Based on the response surface method,the optimized process parameters for extracting essential oil from the peel of Gannan navel orange by squeezing method are obtained:the ratio of material to liquid is 1:4,the concentration of soaking agent Ca(OH)₂is 2.96%,the soaking time is 3.00 h,and the concentration of demulsifier Na Cl is 0.518%.Under optimized conditions,the actual extraction rate was 0.552±0.01%and the theoretical extraction rate was 0.549±0.01%.Then examine the antioxidant properties and whitening effects of the six essential oils.The experiment includes DPPH free radical scavenging experiment,ABTS free radical scavenging experiment and the determination of total reducing capacity.The results show that the scavenging effect of squeezed essential oil on free radicals is better than that of steam essential oil.Comparison of cleaning ability:golden bergamot essential oil>citron essential oil>Gannan navel orange essential oil.The whitening effect was investigated using tyrosinase inhibition experiments,and the results showed that six citrus essential oils have good inhibitory effects and can present a dose relationship with IC₅₀of 1.62 mg/m L?1.74 mg/m L.The golden bergamot squeezed essential oil with the best inhibitory effect was used to study the whitening mechanism,and the type of tyrosinase inhibition was determined to be non-competitive inhibition,that is,the essential oil can bind to the tyrosinase simultaneously with the substrate.Secondly,we investigated the antibacterial properties of the six essential oils.The main inhibitors were Escherichia coli,Staphylococcus aureus,Bacillus subtilis,Candida albicans and Aspergillus niger.The experimental results show that the six essential oils have significant broad-spectrum antibacterial properties,and the range of inhibition zone of the six essential oils is 9.56 mm?15.59 mm.Observation by scanning electron microscope on the surface of the bacteria treated by golden bergamot squeezed essential oil will find that the damage is severe,which further verifies the antibacterial effect.Finally,based on the antioxidant properties of citron squeezed essential oil and the antibacterial properties of navel orange squeezed essential oil,a hand cream and a hand sanitizer were developed and their stability was investigated.The by-product golden bergamot pomace of essential oil extraction is used to prepare fruit wine and optimize its process.The optimized process conditions are 2%yeast inoculum,fermentation temperature 26?,initial sugar content 22%,and initial p H 4.0.The results showed that the ethanol content was 3.2%,the total acid content was 0.3 g/L,and the total sugar content was 1.5 g/L.The wine is clear and bright,has a pure taste,and has the unique aroma of golden bergamot,with a sensory score of 92 points.