Optimization For Extraction Process Of Flavonoids From Shitougan By Response Surface Methodology

Shitougan（Citrus reticulata Blanco cv.Manau Gan）originated in Ankang City,Shaanxi Province.It is named for its crumpled peel like large meatball.It’s a local famous and excellent fruit.Shitougan contains a variety of antioxidants and minerals and other nutrients components.It has strong health effects and medicinal value,such as fire clearing and invigorating spirit,and relieving cough with lijin,the research value is increasingly high.In this study the peel and flesh of Shitougan as the research object,on the basis of solvent selection test and single factor test,the optimum extraction solvent and three groups of optimum levels were selected.The extraction technology of total flavonoids from the peel and flesh of Shitougan was optimized by Box-Benhnken experiment design with three groups of factors:extraction temperature,extraction time and ultrasonic power that to preliminarily explore the extraction technology of total flavonoids from Shitougan,provide theoretical basis and technical reference for further utilization of Shitougan resources,and also better improve the added value of Shitougan.The main research results are as follows:（1）The optimum solvent for extracting total flavonoids from peel of Shitougan was75%ethanol,the optimum extraction parameters for extraction of total flavonoids from peel of Shitougan were as follows:extraction temperature 60℃,33 min extraction time,ultrasonic power 70W,solid-liquid ratio is 1:35（g/mL）,with the yield of 2.26%.（2）Fitted a model which can be used to analyze and predict the total flavonoids extracted from the peel of Shitougan:Y=2.27+0.048×A+0.14×B+0.012×C-0.065×A²-0.25×B²-0.13×C²(R²_adj=0.9449)（3）The optimum solvent for extracting total flavonoids from peel of Shitougan was75%ethanol,the optimum extraction parameters for extraction of total flavonoids from flesh of Shitougan were as follows:extraction temperature of 55℃,31 min extraction time,ultrasonic power 70W,solid-liquid ratio is 1:35（g/mL）,with the yield of 0.29%.（4）Fitted a model which can be used to analyze and predict the total flavonoids extracted from the flesh of Shitougan:Y=0.3+0.005×A+0.005×B+0.01×C-0.012×A×B-0.042×A²-0.037×B²-0.032×C²(R²_adj=0.9555)The technological conditions proposed in this study can be used to extract total flavonoids from the peel and pulp of Shitougan,with the yield of 2.26%and 0.29%.