胡萝卜汁中色素稳定性分析

Stability Analysis of Pigment in Carrot Juice

通过测定胡萝卜汁中色素吸光度的变化并计算其吸光度残存率,探讨不同光照条件、温度、pH、蔗糖浓度、防腐剂及金属离子对胡萝卜汁中色素稳定性的影响。结果表明:胡萝卜汁中的色素具有极佳的热稳定性与耐糖性;具有一定的光稳定性,但对日光直射较敏感;在偏酸性条件下较为稳定,在对胡萝卜汁进行酸化护色时,最佳pH值为6.0~6.5;苯甲酸钠对胡萝卜汁中的色素有一定的增色作用,山梨酸钾对胡萝卜汁中的色素有一定的破坏作用;Na^+、Al^(3+)、Ca^(2+)对胡萝卜汁中的色素有护色作用,K^+对胡萝卜汁中的色素有增色作用,Fe^(3+)、Fe^(2+)、Cu^(2+)会使胡萝卜汁产生明显变色现象,在胡萝卜汁生产与储藏过程中应尽量避免与Fe^(3+)、Fe^(2+)、Cu^(2+)接触。

By studying on the changes of the absorbance of pigment in carrot juice and calculating residual rate of absorbance under different conditions, the effects of different light conditions, temperatures, p H, sugar contents,preservatives and metal ions on the stability of pigment in carrot juice were discussed. Research results showed that：the pigment in carrot juice had excellent thermal stability, sugar tolerance and certain light stability, but it was more sensitive to direct sunlight. It was stable in an acidic environment, the optimal pH was 6.0 ~6.5 during the acidification process of carrot juice for colour keeping. Sodium benzoate showed certain hyperchromic effect on the carrot juice, while potassium sorbate had destructive effect. Na^＋, Al^3＋ and Ca^2＋ had some protective effect on the pigment in carrot juice, K^＋ had certain hyperchromic effect, while Fe^3＋, Fe^2＋ and Cu^2＋ obviously could change the colour of carrot juice, which suggested that it was necessary to avoid contact with Fe^3＋, Fe^2＋and Cu^2＋ during production and storage of carrot juice.