Studies on extraction and physical-chemical properties of anthocyanin from Red Globe grape peel

Extraction method and physical-chemical properties of anthocyanin from Red Globe Grape (Vitis vinifera L.) peel were preliminarily studied. Results showed that the highest extraction efficiency of anthocyanin could be obtained by 1% HCl-methanol. 95% Ethanol-1.5 mol/L HCl (v/v=85/15) and 1% HCl-ethanol were also the optimum extractors of anthocyanin. When 1% HCl-ethanol used,the optimum ratio of grape peel and extractor should be at 1∶5 to 1∶10(g∶mL). Pigments from grape peels were a kind of anthocyanin based on their absorption spectrum. pH value of anthocyanin solution had significant effects on the stability of anthocyanin. When pH≥9 the special absorption spectrum of anthocyanin disappeared. pH value of anthocyanin solution should be kept at 2 to 3. Anthocyanin had hot stability when heated temperature ≤60 ℃.The degradation of anthocyanin could be accelerated under sun light. Heated anthocyanin degraded more quickly under sun light than in dark place. Fe3+ had more deleterious effects on anthocyanin than Zn2+,Ca2+. High concentrations of sucrose and fructose could maintain its color. Compared with sucrose and fructose,glucose had no significant effects on anthocyanin. Vitamin C and sodium benzoate decreased its stability.