Study On The Extraction And Properties Of Pigment From Purple Potato Peel

Purple potato peel pigment is one of the natural water-soluble red pigment,which extracted from purple sweet potato peels and it belongs to the anthocyanin class. It exists in the purple potato roots, stems, leaves and purple potato peels.Anthocyanin pigments have a variety of characteristics such as: anti-mutagenic, antiradiation, anti-oxidant and anti-cancer activity, regulation of blood pressure and other functions. By Box-Behnken experimental design and response surface methodology,the optimum extraction conditions were obtained as follows:?1?Extraction agent ratio of acid to alcohol 1:1; the ratio of material to liquid1:60; extraction temperature 50 ?; extraction time 10 min. Under such conditions,the absorbance was 0.839, the theoretical prediction value was 0.843.?2?Study on the stability of purple sweet potato peel pigments showed that it was unable in the light and strong alkali conditions?pH>7?. It was relatively stable at the temperature between 4-60? and metal ions of K⁺, Ca²⁺, Na⁺, Zn²⁺. Mg⁺?Cu²⁺?Mn²⁺ ? Fe³⁺ were helpful in the degradation of purple sweet potato peel pigment.Within the maximum usage by food standards, it was hardly affected by benzoic acid,sorbic acid, citric acid, sucrose, soluble starch, glucose, sodium chloride. Therefore, it could be used as food coloring.?3?Study on the anti-oxidation activity showed that: purple sweet potato peel pigment had the ability to scavenge the ·OH,·DPPH,·O₂^-. With purple potato peel pigment mass concentration increased, scavenging capacity were also increased.?4?Optimum formulations of new type purple sweet potato Bahali: purple potato powder 70 g, lemon juice 90 mL, salad oil 180 g, sugar 50 g and the optimum conditions were as follows: Stirring time 15 min, baking time 60 min, baking temperature of 150 ?.