Research On Extraction, Physicochemical Property And Antioxidation Of Purple Dioscorea Batatas Decne

Dioscorea batatas Decne, an annual or perennial twining liana plant, belongs to dioscorea batatas family. It is mainly distributed in tropical and subtropical areas in Africa, South America, and Southeast Asia. Dioscorea batatas Decne is rich in carbohydrates, and also contains protein, various vitamins, chemicals, indicant, and mucilage which are beneficial to human body. It is bright red, and has developed rhizomes in the shape of a sole, thus named. Its colors vary from white to puce (purple). Purple ones indicate that they contain certain pigments, belonging to anthocyanin. Anthocyanin, a kind of flavonoid compound, is an edible natural pigment of water-solubility. At present, few researches have been done on the pigment of Dioscorea batatas Decne. Domestic researches have been limited to the separation and extraction of it. In the paper, the writer has made an initial exploration into the separation and extraction of the pigments in purple Dioscorea batatas Decne, and the stability and the biological activity of extracorporeal anti-oxidation have also been studied in the paper, which has provided a theoretical foundation on which to take advantage of anthocyanin, and develop functionality foods from Dioscorea batatas Decne.Based on Orthogonal experiments, the paper first studies the best technological conditions under which to lixiviate pigments of Dioscorea batatas Decne. The results show that pure anthocyanin can be extracted by filtering steep, adsorbing colophony, decompression and cubage reduction, under the condition that 1.5 percent of citric acid ethanol liquor serves as the best lixiviator, which should be heat up under the constant temperature of 60℃for 60 minutes, and the proportion of general materials should be 1:10.At the same time, the paper also studies the stability of the pigment in purple Dioscorea batatas Decne, showing its stability under the condition of pH<3 high acid liquids, and its unstability under the condition of pH > 5 liquids. It possesses certain heat-resistance, but the temperature should not be over 90℃. It has relatively poor lightfastness. Most metal ions will not have great effects on the stability of the pigment, while Al³⁺,Fe³⁺ do have great impacts, among which Al³⁺,Fe³⁺ tend to increase the absorbency of the pigment.In the paper, two extracorporeal anti-oxidation models have been adopted to study the extracorporeal anti-oxidation of pigment in purple Dioscorea batatas Decne so that the potential of pigment as a function gene of anti-oxidation can be fully understood. The results indicate that pigment in purple Dioscorea batatas Decne possesses considerably strong ability to eliminate·OH and·O₂^-, and its ability has so much to do with its thickness.