溶液pH对番茄红素稳定性及其降解动力学研究

Effect of pH on the Lycopene Stability and Its Degradation Kinetics

摘要:

番茄红素易受溶剂环境的影响造成损失。为揭示溶液环境对番茄红素稳定性的影响规律，本文基于紫外可见吸收光谱的变化研究了二甲基亚砜、四氢呋喃、丙酮等不同溶剂种类、比例及酸碱度对番茄红素紫外可见吸收光谱及其吸收强度的影响，并进行降解动力学研究。结果显示：番茄红素在四氢呋喃和二甲基亚砜溶剂中的特征吸收波长与其在丙酮溶剂相比红移，吸收峰3的波长由505 nm分别红移至511 nm和523 nm；番茄红素在有机溶剂水溶液体系中均呈H型聚集，光谱表现为吸收波长蓝移；番茄红素在有机溶剂中的降解均符合一级反应动力学，其在丙酮水溶剂中的半衰期为25.48 h；番茄红素在弱酸和弱碱性条件下更稳定。结果表明：弱酸性或弱碱性的丙酮和四氢呋喃水溶液可作为番茄红素的良好溶剂，本研究为番茄类食品的储藏、加工及开发应用奠定理论基础。

Abstract:

Lycopene is susceptible to degradation affected by light, oxygen, heat, solvents and its environment. In order to investigate the effect of solution environment on lycopene stability, the UV-vis spectroscopy character of lycopene with different solvents and its degradation kinetics were analyzed in thiswork. The solvents were including dimethyl sulfoxide (DMSO), tetrahydrofuran (THF) and acetone. The results showed that the characteristic wavelength of lycopene in different solvents appeared the redshift distribution from acetone of 505 nm to DMSO of 511 nm and THF of 523 nm in UV-vis spectroscopy. Lycopene represented as H-type aggregation and observed the blue shift of the maximum of UV absorption peak in water-organic solvent. The experimental results of degradation kinetics showed that the degradation of lycopene in different solvents conformed to first-order reaction law, and it was stable in acetone solvent with a half-life of 25.48 h. The lycopene were stable in acidic and alkane media, but limitedly resistant to strong acid and alkali solution and strong solvent. These results indicated that lycopene was suitable for keeping stability under weak acid and alkane media of acetone and THF aqueous solutions. This study provided a theoretical basis for processing, packaging, and storage of tomato products.