Optimization Of Hydrothermal Extraction Process Of Quercetin From Mistletoe Leaves

Quercete leaf is a kind of rich source of biomass resources,the leaves,skin and seeds of quercete tree have medicinal value,there is a great potential for development and utilization,quercete tree material is hard,can be used as a flooring material.Quercus can be used as a green packaging material,in Japan,Korea and other places very popular.Quercetin leaves are rich in flavonoids,chlorogenic acid,tannins and other polyphenols.In recent years,more and more research has been done on flavonoids,and the extraction process is also diversified.Therefore,it is an urgent problem to improve the extraction amount of flavonoids.Quercetin,a flavonoid with high added value,was extracted from quercetin with quercetin leaves.In view of the shortcomings of the traditional extraction method with low extraction efficiency,it is proposed to use hydrothermal method to efficiently extract quercetin,and compared the traditional extraction and hydrothermal extraction.For traditional extraction,the extraction was verified under the conditions of reaction temperature 85℃,reaction time 5 h and ethanol volume fraction 60%,and the extraction amount of quercetin was 6.36 mg/g.In order to determine the optimal conditions of hydrothermal method,first,single factor experiments were conducted to study the effects of liquid-material ratio,reaction time,reaction temperature and ethanol volume fraction on the extraction amount.The single-factor experiment obtained the reaction threshold of ethanol volume fraction of 50%～70%,the liquid-material ratio of 10～50 m L/g,the reaction time of 3～7 h,the reaction temperature of 160～200℃.Considering single factor experiment results introduced the result of the single factor,on the basis of single factor experiment,through the response surface analysis and optimize the extraction conditions,the optimum technological conditions were determined as follows:64.67% ethanol volume fraction and liquid ratio of 39.77:1 m L/g,5.42 h reaction time,reaction temperature 188.77℃,the optimum extraction conditions of extraction quantity is 36.09 mg/g,contrast to the traditional formulation data,underthe traditional extraction method of extracting amount was 6.36 mg/g to contrast the traditional formulation data,the influence of various factors on the extraction amount for: liquid to material ratio > Reaction time > ethanol volume fraction >reaction temperature.Second,with it belong to a class of fresh and dried leaves and cyclobalanopsis leaves fall leaves respectively in the comparison of traditional method and hydrothermal method,under the traditional method of fresh and dry cyclobalanopsis leaf income amount of quercetin extracted were 3.06 mg/g and 7.44 mg/g,hydrothermal method under the fresh and dry cyclobalanopsis leaves the extraction of quercetin were 14.39 mg/g and 25.87 mg/g,under the traditional method of fresh and dry fall leaf income amount of quercetin extracted were 2.30 mg/g and 6.21mg/g,The extraction of quercetin from fresh and dry chestnut leaves by hydrothermal method was 16.40 mg/g and 29.34 mg/g,respectively.Finally,the composition and microstructure of quercetin were characterized.The contents of cellulose,hemicellulose and lignin in the leaves were determined to be 20.15%,7.50% and 2.28%,respectively.The water content of fresh quercus was67.31%,volatile content was 15.37%,fixed carbon content was 12.10% and ash content was 5.22%.The microstructure of the leaves of quercus sativusl.The thermal stability of quercus leaves at different stages was obtained by thermogravimetric analysis.Before 210℃,the weight loss of quercus was not obvious.A large number of organic components were pyrolysis at 210℃～500℃,and the weight loss was very significant.