低盐腌制白萝卜非酶褐变动力学

摘要

探讨白萝卜腌制过程中非酶褐变的原因与动力学，以期为白萝卜的腌制加工提供技术指导。在25、30、35℃条件下对白萝卜进行自然发酵，研究产品中与非酶褐变有关的指标总酚、还原糖、VC、游离氨基酸、5-羟甲基糠醛（5-hydroxymethylfurfural，5-HMF）含量以及褐变度（browning degree，BD）及色差（L*、a*、b*）的变化，并分别用零级、一级动力学模型进行拟合分析。结果表明：白萝卜腌制期间发生非酶褐变主要是由于美拉德反应及多酚的氧化聚合引起的。在不同温度（25、30、35℃）条件下发酵过程中，白萝卜的总酚、还原糖、游离氨基酸含量变化符合一级动力学模型；5-HMF含量、BD变化符合零级动力学模型，并且两者成线性关系（R2＞0.9360），同时颜色指标L*、b*值是5-HMF的函数，可用一级动力学方程表示（R2＞0.8012）。发酵温度对腌制白萝卜成品品质影响显著，因此可通过控制发酵温度来提高产品的感官及营养品质。%The paper discusses the causes and kinetics of non-enzymatic browning during pickling of radish, which is expected to be helpful for the processing of radish. The radish was fermented spontaneously at different temperatures (25, 30 and 35℃) in this study. Changes in qualities related to non-enzymatic browning include total polyphenols, reducing sugar, vitamin C, free amino acid, 5-hydroxymethylfurfural (5-HMF), browning degree (BD) and color parameters (L*, a*and b*) were studied and fitted with zero order and first order models, respectively. The browning of pickled radish was non-enzymatic browning, which was mainly due to Maillard reaction and oxidative polymerization. The first order model could better explain the kinetic changes of total polyphenols, reducing sugar, and free amino acids in radish during pickling. The changes of 5-HMF and BD accorded with zero order model, and a good correlation between 5-HMF and BD was observed (R2> 0.936 0). Color parameters (L*, and b*) could be expressed by a first-order kinetic equation (R2>0.801 2). The fermentation temperature had a significant effect on the quality of pickled radish products, and the quality of pickled radish can be improved by controlling fermentation temperature.