フィリピン産紫ヤム塊根粉末中のアントシアニン色素の安定性　　無機塩，有機酸，糖，フェノール，Ｌ‐アスコルビン酸および過酸化水素の影響

A comparative investigation was conducted on the effect of various additives on various anthocyanine pigments (AN_s) of a purple yam (UBE), a purple sweet potato (SP), grapes (GJ), purple corn (PC) and a red cabbage (RC) to obtain the following results.<BR>1) When inorganic salts were added to various ANs, UBE AN was lower in the increase rate of absorbance as compared with the ANs of the others but SP AN drastically increased in absorbance. However, the addition of FeSO₄ and CuSO₄ allowed various ANs to change to orange and blue colors and became the cause of fading.<BR>2) When organic acids are added to various ANs, these ANs increased in absorbance as the concentration of the organic acids increased. Especially, UBE and SP AN markedly increased in absorbance. Further, various ANs increased in absorbance as the basicity of each organic acid increased in the order of a monobasic acid, a dibasic acid and a tribasic acid.<BR>3) When sugars are added to various ANs, GJ, PC and UBE ANs increased in absorbance. Moreover, in the ANs of these species, linear relation was confirmed between sugar concentration and absorbance.<BR>4) In the fading rates of various ANs ({(absorbance before heating - absorbance after heating) /absorbance before heating} × 100), when organic acids, sugars and phenols (other than gallic acid) were added, UBE AN was most stable as compared with ANs of the others in the same way as that at the time of non-addition. However, when inorganic salts were added, RC AN became lowest in a fading rate and UBE AN became stable but there is no great difference in the fading rate and UBE AN was also relatively stable.<BR>5) As the concentration of L-ascorbic acid and that of hydrogen peroxide became high, ANs was decomposed with the elapse of time. When hydrogen peroxide was added, UBE AN was lower in a pigment residual rate as compared with ANs of others and unstable.