Research of the stability and content detection of anthocyanin of black peanuts clothing

The experiment determined the containment of anthocyanins from the black peanut and stability of the anthocyanins under different temperature, pH, illumination conditions and different concentration of metal ions (Cu 2+ , Mn 2+ , Mg 2+ and Fe 3+ ) . The anthocyanin was extracted under the optimum technological condition:ratio of material to liquid 1∶50, 60% ethanol as extractant, extraction temperature 60℃ and time 60min. The black peanut clothing contained 10.3mg/g anthocyanins, of which the absorbance decreased with the increasing of pH when pH lowered 5.0 but increased after the pH was higher than 5.0 and the color turned to the trend of blue gradually. Also, the closer the pH reached to 7.0, the better preservation rate of anthocyanin it had. Apparently , the absorbance stayed at the highest level when the concentration of Mn 2+ or Mg 2+ was 2.00mmol/L and it rose with the concentration of Fe 3+ or Cu 2+ increasing. No flocculation was found to the anthocyanins by Fe 3+ .