Study On Extraction, Structure Identification, Stability And Antioxidant Of Anthocyanins From Purple Radish

Anthocyanins are responsible for the orange to blue coloration of plant. They are beneficial to human health and widely used as food colorants. Purple radish (Raphnus sativus cv.), a new variety of radish, is composed of abundant anthocyanin that make it a potential resource for natural pigment.The extraction, stability and conponents of the anthocyanins in purple radish were studied in this paper. Main results showed as follows:1. The extraction of anthocyanins from purple radish was studied using ultrasound as the assisted method.The Orthogonal test design was used to ascertain the optimum technologies of ultrasonic assistant extraction after 2h shaking .The optimum conditions for ultrasonic extracting were as follows: The extraction time is 20min; the extraction times is 1; the concentration of acetron solution is 70%; the ratio of material to reagent is 1: 60.2. PC can be used as an assistant method in pigments component analysis by Xin Hua No.3 filter paper. The HPLC methods were well determined for pigments in purple radish. of those the column: inertsil(?) ODS C18(5um, 4.6×250mm); elution solvent : (A) 100% HPLC-grade acetonitrile and (B) 1% phosphoric acid(concentrated), 10% acetic acid (glacial), 5% acetonitrile(v/v/v). elution Conditions: grade elution; Flow rate: 1ml/min; Injection volume: 20ul; UV/Vis spectrophotometry, detection at 520nm. The anthocyanins of purple radish are indentified preliminary by comparison with data in the literatures. The results showed that the anthocyanin of purple radish may be conclude pelargonidin-3-5-diglucose.3. The research has been made on stability of the anthocyanins in purple radish. Conclusion was drawn that the indoors nature light, temperature, cane s ugar, glucose, salt, reductant, antiseptic, K⁺,Na⁺,Ca⁺,Mg²⁺ etc.have no significanteffects on the stability of the anthocyanins;outdoors nature light, hydroperoxid e, lemon acid, vitamin C, PH, Cu²⁺, Mn²⁺, Al³⁺, Fe³⁺ etc. have badly destroyi ng power to the anthocyanins.4. The in vitro antioxidant activities of anthocyanins from purple radishes,purple sweet potatoes and purple cabbages extracts were studied and evaluat ed. comparing antioxidant abilities among them by DPPH method, It was found that their IC50 value on scavenging DPPH free radical were 0.0121mg/ml,0.0165mg/ml,0.0187mg/ml. Assessing inhibition ability on oxidation, induced by Fe2+, of lecithin liposome system of anthocyanins among them, the antioxidant activities of the differet pigment extracts were found to vary as follows: purple sweet potatoes > purple radishes > purple cabbage.