Study On Extraction, Isolation And Purification, Activities Of Anthocyanins From Three Kinds Of Purple Vegetable

In this paper, Three kinds of purple vegetables which were purple onion, purple cabbage and purple sweet potato were used as raw material. The condition for extraction and purification of anthocyanins from purple onion, purple cabbage and purple sweet potato had been evaluated and optimized. The anthocyanins in three kinds of purple vegetables were identified primarily. Their anti-oxidation ability and antimicrobial activity were comparative study. Main results for this study are as follows.The optimum extraction conditions of anthocyanins were determined by single-factor and response surface experiments. The optimum condition of purple onion:The volume fraction of ethanol was72%, the ratio of solid to liquid was1:32, the extraction temperature was57℃, the extraction time was26min. The extraction yield of anthocyanins under these conditions was154.38mg/100g. The optimum condition of purple cabbage:The volume fraction of ethanol was58%, the ratio of solid to liquid was1:39, the extraction temperature was47℃, the extraction time was37min. The extraction yield of anthocyanins under these conditions was252.09mg/100g.The optimum condition of purple sweet potato:The volume fraction of ethanol was61%, the ratio of solid to liquid was1:20, the extraction temperature was48℃, the extraction time was28min. The extraction yield of anthocyanins under these conditions was154.38mg/100g.Extraction, purification and identification of anthocyanins:Among5macroporous resins tested, AB-8with high adsorption and high desorption rates was used to purify the crude anthocyanins extract. The optimum purification conditions were determined by adsorption and desorption test of static and dynamic. Because of the similar purifying process of three kinds of anthocyanins. The optimum purifying process was:Adsorption equilibrium time was4hours, desorption equilibrium time was2hours, ethanol concentration was65%(pH=2), the sample concentration:0.6mg/mL, the flow rate was0.8mL/min, the sampling amount was360mL, desorption rate1.0mL/min. Sample yield of purple onion anthocyanins was68.35%, sample yield of purple cabbage anthocyanins was70.69%, sample yield of purple sweet potato anthocyanins was67.49%.Investigation antioxidant activity of three kinds of anthocyanins. Three kind of anthocyanins were made to scavenging radicals and compared, and Vc as the contrast. the experimental results was as follows. The ability of scavenging hydroxyl radical:Vc(65.89%)> purple onion (55.69%)> purple cabbage (45.80%)> purple sweet potato (35.21%); The ability of scavenging DPPH radical: Vc(92.39%)> purple onion (71.38%)> purple cabbage (55.39%)> purple sweet potato (43.30%); The ability of scavenging O2-radical:Vc(64.87%)> purple onion(48.59%)> purple cabbage (30.09%)> purple sweet potato (23.08%); The ability of anti-liposome:Vc(55.98%)> purple onion (32.01%)> purple cabbage (27.34%)> purple sweet potato (29.67%)。Compared with penicillin sodium, anthocyanin purification from three kinds of vegetables could inhibit the groeth of some usual microorganism. The result was as follows.the inhibition effects of Escherichia coli:penicillin sodium> purple cabbage> purple onion> purple sweet potato; the inhibition effects of B. subtilis:penicillin sodium> purple onion> purple cabbage> purple sweet potato. the inhibition effects of Rhizopus:penicillin sodium> purple onion> purple cabbage=purple sweet potato; few effects on molds Aspergillus niger.