紫甘薯色素理化性质及稳定性研究(9200字)
摘 要：本文以紫心红番薯为原料，用酸化乙醇提取紫甘薯色素，对其色素的理化性质及稳定性进行了研究。结果表明：紫甘薯色素易溶于水、甲醇、乙醇，不溶于丙酮、乙酸乙酯、乙醚和石油醚；紫甘薯色素水溶液在pH值为1.0～3.0时，性质稳定，呈鲜红色，随pH值升高色素颜色变浅，保存率减小；温度为20～60℃时，色素性质稳定，温度超过60℃时，色素稳定性迅速下降；光照对色素稳定性影响较小，连续照射3.5h后色素保存率为84%；食品添加剂亚硫酸钠和亚硝酸钠对紫甘薯花色苷具有破坏作用，苯甲酸钠对紫甘薯花色苷没有不良影响；Cu+2 、Al+3、Zn+2 、草酸、苹果酸、柠檬酸、蔗糖、葡萄糖、食盐对紫甘薯花色苷均有不同程度的增色作用，Cu+2 、Al+3和Zn+2具有护色效果，可提高色素的稳定性，而Fe+3对色素有破坏作用。
关键词：甘薯；紫甘薯色素;理化性质;稳定性
Study on the Physical and Chemical Properties of Pigment from Purple Sweet Potato
Abstract：This paper with purple sweet potato as the material, the basic physicochemical property of its pigment and the effects of pH value, temperature, light, food additives, reductant-oxidant and metal ions on the stability of pigment were studied. The results show the pigment from purple sweet potato was easily soluble in water, methanol and ethanol, but insoluble in acetone, ethyl acetate, ether, and petroleum ether. When the pH value of aqueous solution of pigment from purple sweet potato was 1.0-3.0,the properties of the pigment was stable, bright red, and with the increase of pH value, the pigment colour became shallower, and its save rate decreased. When the temperature was 20-60℃,the properties of the pigment was stable, and when the temperature was over 60℃,the stability of the pigment was decreased rapidly. The effects of light on stability of pigment was little, after 3.5h continuous irradiation, the preservation rate of pigment was 84%.The food additives as NaHSO3 and NaNO2 were added, the anthocyanins pigment was damaged. Sodium Benzoate had no harmful effect on it. Metal ions, organic acids, sucrose, glucose and salt had different color-protecting capability.Cu+2, Al+3 and Zn+2 had an effect of protecting the color of pigment, and could improve the stability of the pigment, but Fe+3 had a destructive effect.
Key words: Purple sweet potato; Pigment from purple sweet potato; Physical and chemical properties; Stability
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