The Research On Extraction And Stability Of The Anthocyanins In Purple Potato

There is a natural anthocyanin pigment in purple potato, and less pigment is in the free state in potato tube, generally it is bonded formation of anthocyanins with sugar through the glycosidic. At present, the research of domestic and abroad on purple potato mainly focus on several aspects, such as the varieties breeding of purple potato, the composition and structure analysis of anthocyanins molecular, and so on. There is less study which about the stability of anthocyanins in purple potato. The products made up of a purple potato are seen rarely. This paper mainly studied the extraction of anthocyanins in purple potato, the study about the effects of environmental conditions on the stability of anthocyanin and how to improve the stability of anthocyanins in purple potato. What the purpose is laying the foundation for the development of anthocyanins in purple potato. In this paper, the research content mainly includes the following points:1. Anthocyanins extracted. The anthocyanins concentration was measured by pH differential method; and anthocyanins was obtained by ultrasonic-assisted extraction. The optimum extraction condition was gained by single factor tests, when the lactic acid concentration, time, temperature and the ratio of material liquid were 3%,30min,45 ℃ and 1:60, respectively. The anthocyanins concentration could reach to 140.19mg/100g.2. The reaserch of stability effects on the anthocyanin. Studies show that when the pH was 2 and 3,the basic structure of anthocyanins were not damaged and the color of the solution was red. When the pH was 4,5, 6,the preservation rate of the basic structure of anthocyanin was above 85% and the color was pink. When the pH was 7, the preservation rate of the basic structure of anthocyanin was 80% and the color was blue. When the pH was 8, The preservation rate of the basic structure of anthocyanin was around 50% the and the color was blue and green.With the increase of temperature, the preservation rate of the solution of pH 3、pH 4 and pH5 were decreased; With the prolongation of the heating time, the reservation rate of the solution of above three pH were also decreased.Light tests show,indoor scattered light has a certain influence on anthocyanins. When a short exposure to the ultraviolet rays, long wave and medium wave has no effect on the preservation rate of anthocyanins but short wave had a greater influence on the preservation rate of anthocyanins.3.To improve the stability of anthocyanins. The results showed that anthocyanins survival rate could be improved slightly by adding phytic acid sodium; anthocyanins survival rate could be affected markedly by ascorbic acid and sodium bisulfite. In metal ions, Zn2+ could improve the survival rate of anthocyanins; but, the interference effects of Fe3+, Fe2+ and Cu2+ were evident to anthocyanins solution primary. In sweeteners, glucose and trehalose could be improving the survival rate of anthocyanins and protecting the anthocyanins. In addition, radish red and red flowers red pigment, could deepen the color of the solution and stable colour of anthocyanins solution.