Extraction, Separation, Purification And Antioxidant Activity Of Raspberry Anthocyanins

The subject of raspberry anthocyanins preparation were studied by comparing effect of the different extraction methods, I optimized the extraction method of anthocyanins. The crude extract of anthocyanins were separated and purified through column chromatography, and its antioxidant activity in vitro was analysed. The results of this study are as follows:1. The raspberry anthocyanins extraction process parameters were studied and optimized to obtain the optimum parameters of each factor: ethanol concentration was 70%, material to liquid ratio was 1:8 g/mL, extraction time was 90 min, extraction temperature was 70 ℃. The optimum extraction conditions were optimized by response surface method. The extraction conditions: ethanol concentration was 66%, solid-liquid ratio was 1:8.2(g/m L), extraction time was 85 min, extraction temperature was 71℃, and anthocyanins yield was 1.5%, and the purity was 12.31%.2. We selected AB-8 resin from 8 kinds of macroporous adsorption resin as filler, through static adsorption and dynamic adsorption experiments, the concentration of the sample was 0.94 g/L, the sample flow speed was 500 mL/h, pH value was 3.0, the sample amount was 8000 mL. The elution test showed that the elution solution selected 80% ethanol solution, the elution l was 750 mL/h, the solution pH value was 3.0, the elution agent dosage was 1000 m L. The desorption rate could reach 93.12%. The purity of anthocyanins increased from 12.31% to 63.77% and the recovery rate was 88.82%.3. Raspberry anthocyanins were separated and purified using silica gel column chromatography, the optimization parameters were obtained as follows: the eluent, 8:2:1(Butyl alcohol-acetic acid-water); the ratio of diameter to height was 1:14; crude raspberry: silica gel was 1:200, the flow rate was 2 mL/min. After separation, the composition RA1 and RA2 were collected, the yields were 0.51% and 0.62%, respectively, and the purity were 84.1% and 82.8%, respectively.4. The DPPH free radical scavenging, ABTS radical scavenging, total reducing capacity were determined for the evaluation of antioxidant activity in vitro of the purified raspberry anthocyanins. The antioxidant capacities of the two raspberry anthocyanins samples were better than that of ascorbic acid, and the antioxidant activity of the raspberry anthocyanin RA1 component were better than RA2 composition in the evaluation of three experiments.