大枣浓缩汁贮藏过程中非酶褐变动力学研究

Kinetic study of non-enzymatic browning in Chinese jujube concentrate during storage

在4,26,37℃条件下对大枣浓缩汁进行7个月的贮藏,并分别用零级、一级动力学模型对产品中与非酶褐变相关的指标还原糖、抗坏血酸(Vc)、羟甲基糠醛(HMF)随贮藏时间的变化进行拟合分析。结果表明:还原糖含量的动态变化零级模型拟合度优于一级的,Vc含量的动态变化一级模型拟合度优于零级的。4,26,37℃贮藏条件下,大枣浓缩汁中的HMF和A420变化呈线性关系,同时颜色参数(A420、L*、Chroma值)是HMF的函数,具有相关性,可用一级动力学方程表示。26,37℃贮藏过程中大枣浓缩汁的颜色参数及还原糖、Vc含量变化显著(P<0.05),明显高于4℃贮藏,低温有利于大枣浓缩汁的贮藏。

Changes of qualities related to non-enzymatic browning in Chinese jujube concentrate at different storage temperatures（4 ℃,26 ℃and 37 ℃）for 7 months were evaluated.Changes of reducing sugar,vitamin C,5-hydroxymethylfurfural（HMF）were fitted with zero-order,first-order models respectively.The results showed that the fit of the zero-order model was superior to the first-order model to explain the kinetic changes of reducing sugar,and the fit of the first-order model was superior to the zero-order model to explain the kinetic changes of Vc.At 4 ℃,26 ℃ or 37 ℃,a correlation between HMF formation and A420 was observed,and color conditions（A420,L^＊,Chroma）could be expressed by first-order equations as functions of HMF.Higher storage temperature（26 ℃and 37 ℃）had significant effects（P〈0.05）on changes of color conditions（A420,L^＊,Chroma）,reducing sugar,vitamins C in Chinese jujube concentrate,significantly higher than 4 ℃ storage,could be protect well during lower temperature storage.