Study On Extraction, Purification, Identification And Antioxidant Activity Of Blueberry Anthocyanins

Blueberry is one of the most representative berries in Chinese ecological economic forest. It is popular with people because of rich nutrition, unique flavor and good taste. Study found that the active substance contained in blueberries have a variety of physiological effects such as antioxidation, anti-aging and anti-inflammation. Anthocyanins were the most prominent effective components. The extraction separation and purification of anthocyanin from "Patroit" blueberry was studied in this paper. It systematically analyzed the content and types of anthocyanins and the antioxidant activity in vitro of the purified blueberry anthocyanins were analyzed.In the first part of this paper, the effects of ultrasonic assisted ethanol extraction were explored. The results of single factor experiments showed that liquid-solid ratio, methanol gasoline volume and ultrasonic power have significant effect to the extraction of anthocyanins. The optimum extraction technology through the response surface plot were as follows:the ratio of sample to solvent 1:8g/mL, methanol gasoline volume 63%, ultrasonic power 450 W, ultrasonic temperature 50℃, ultrasonic time 50min. Under this condition, extraction rate of blueberry anthocyanins was 3.927 mg/g.The determination of anthocyanin in blueberry were studied in the second part. This article used technology of HPLC/LC-MS combined with UV-Visible spectrum to preliminarily identified anthocyanins component. The result of the pH differential method showed the anthocyanins content in fresh fruit was 392.7 mg/100g and 398.5 mg/100g was determined by HPLC method. In the structure elucidation,10 components was preliminarily identified De-3-O-hex, Cy-3-O-hex, De-3-O-pen, Pet-3-O-hex, Cy-3-O-pen, Peo-3-O-hex, Pet-3-O-pen, Mal-3-O-gal, Mal-3-O-glu, Mal-3-O-pen.The paper further studied the separation and purification. The anthocyanins were extracted with ethyl acetate, which had no affect on anthocyanins types and ratio of peak area. But a part of oil-soluble flavonoids impurities was removed by ethyl acetate. It showed that the optimum conditions for separating anthocyanins by XAD-7 macroporous resin was 60% acidic methanol and the anthocyanins purity was 58%. The paper also discussed the extraction and purification of blueberry anthocyanins by sephadex LH-20. It showed that optimal extraction conditions were as follows sample loading volume was 20mg, eluting method was mixture velocity elution by 30% ethanol. The elution fractions Ⅳ, Ⅴ,Ⅵ,Ⅶ were anthocyains, identified by the scanning of UV-Visible wavelength. The results from HPLC analysis showed that fraction Ⅳ only contained Mal-3-O-gal whose purity was 78.6%, the purity of fraction Ⅴ,Ⅵ, Ⅶ reached 69.2%,73.57%,75.8% respectively and mainly contained two anthocyanins.The final part of paper studied antioxidant activity of blueberry anthocyanins fractions. It showed anthocyains had effect of the inhibition of lipid peroxidation, scavenging DPPH and hydroxyl radicals. The antioxidant effect of four fractions from LH-20 gel separation were superior to products by macroreticular resin purification. The fraction VI had prominent antioxidative activity among them, followed by Ⅷ.