Abstract:

The crude anthocyanin from purple potato was prepared by solvent extraction extracted by solvent, and the influences of pH, temperature and light was investigated as well as its stability in the terms of metal iron, oxidant, reducers, preservative, salt and sugar. The results showed that the anthocyanins are water soluble pigments and displayed a clear λmax at 536 nm. A significant effect of pH was observed that anthocyanin showed a relative stability under acidic condition. In addition, the anthocyan was comparatively stable within 70 ℃ and sunlight could accelerate the degradation of the anthocyanin. Metal ions such as Al3+、Zn2+、Na+ and Ca2+ had no marked influence on the color of anthocyan while pronounced effects of Sn2+、Fe3+ were found. Furthermore, this anthocyanin showed a poor oxidation and reduction resistance. Conventional food additives such as preservative, salt and glucose did not exert negative effects on the stability of the anthocyanin.

Key words: purple potato, anthocyan, stability, physico-chemical properties