紫色甘薯花色素苷色泽稳定性研究

利用红外光谱、紫外光谱等方法，研究了酸、碱、空气、食品添加剂和氧化剂、还原剂等因素对紫色甘薯花色素苷色泽的影响．结果表明，紫色甘薯花色素，在强酸条件下较稳定，几乎不受温度、光照等的影响，但随着碱度的增加，花色素的色泽由红变紫、变蓝；在空气中是比较稳定的；葡萄糖、蔗糖、K2Cr2O7和Na2S2O3几乎不影响花色素的稳定性，而食盐、可溶性淀粉、5％和5％ Vc则能较明显地降低花色素的稳定性．紫外扫描和红外扫描结果推测紫色甘碧花色素色泽的变化可能是由于其主体骨架由三环共面结构转化为三环不共面结构．

Studies on the Hue Stability of Anthocyanin in Purple-Sweetpotato

It was sensitive for anthocyanin to pH value of solution and temperature. Anthoocyanin in O_2 or in acidic media was much more stable than in alkaline media. Strong alkaline would cause an irreversible change in the hue loss of anthocyanin. There had hardly effects of sucrose, glucose, K_2Cr_2O_7 or Na_2S_2O_3 on the red hue of anthocyanin. However, salt, soluble starch, H_2O_2 or 5% Vc would make the hue of anthocyanin change in different degree. The results of UV and IR scanning indicated that three rings of anthocyanin in acidic media were coplanar, but those in alkaline media were not in one plane, which would cause the permanent loss of the red hue, even back to strong acidic media.