| Flavonoids, a prominent secondary metabolites in citrus, is widely distributed and abundant in citurs fruits. They possess wide application prospect because of variety biological activities they own, such as anticancer, antioxidant, antibacterial and so on.At present, extract flavonoids from the pericar powder by using organic solvent is the main approach for the extraction of citrus peels flavonoids. While the complex operations such as separating of peels and seeds, drying and grinding were required before extraction. Thus, this extraction method is not suitable for industrial production. Compared with organic solvent extraction, the extraction menthod of flavonoids with water do not need to carry out such complex operations mentioned above. It is an economic, practical, and environmental protection method. In this study, the extraction and purification technology of flavonoids from citrus fruits were investigated with citrus peels residue as raw materials. And the main contents and results are as follows:(1) The content of flavonoids in the citrus peels was determined by Spectrophotometry at the wavelength of 506 nm, with lutin as standard sample and NaNC,A1(NO3)3,NaOH reagent as the indicator. The result shows that there is a linear relationship between the concentration of the flavonoids solution and the absorption spectrum. The linear regression equation was y=8.7214x+0.0144, R=0.9990. In addition, it was proved that expensive equimpments were not needed in this method, and simple operation, good stability and reliability are the obvious advantages of this method.(2) Different organic solvents were used to extract flavonoids in the citrus peels, while water is the best solvent when considering both the yield and the cost. Therefore, water was choosen as a extraction solvent in this experiment.(3) Extraction of flavonoids from citrus peels with ultrasonic-assisted. On the basis of single-factor test, the mathematical model was established through central composite rotation design and response surface methodology, on the basis of the optimizaiton of the processing time, power, temperature of ultrasonic-assisted and the extraction rate of flavonoids. Variance analysis of the regression model indicated that:the regression equation was significant with good fitting degree. One degree term and second degree term have significant effect on the extraction rate of flavonoids, while the interaction between various factors has significant effect; the material to water has the greatest effect on the extraction rate of flavonoids under ultrasonic-assisted extraction condition, followed by the temperature, power and time. According to this model, the extraction rate of flavonoids is 1.06% in the condition of ultrasonic-assisted time 41 min, ultrasonic-assisted power 140 W, ultrasonic-assisted temperature: 57℃and ratio of material to water 1:16.(4) Extraction of flavonoids from citrus peels with microware-assisted. On the basis of single-factor test, the optimum microware-assisted extraction conditions of flavonoids from citrus peels are determined through orthogonal experiment. The experiment result shows that the optimum extraction condition is temperature 65℃, time 4min, ratio of material to water 1:4 and power 700W. And under this condition the extraction rate of flavonoids is 1.03%.(5) The adsorption separation property of flavonoids from citrus peels were studied with the macroporous resin. Five types of macroporous resin were selected to compare their performances in absorbing and desorbing flavonoids. The optional macroporous resin was decided and its dynamic absorbing and desorbing behavior were studied. The results show ed that D101 type macroporous resin possess higher absorption and desorption capacity. The absoroption rate of D101 resin was 82.00%, the utioeln rate was 71.00%. The optimum technological parameters of the purify of flavonoids by D101 are as follows:solution concentration O.lmg/mL, utioeln time 4 hours, and 70% alcohol as the desorption solution.
|
PDF Full Text Request