辣椒红素分子体外氧化防御反应UV-Vis及FTIR光谱特征分析

采用紫外-可见光谱(UV-Vis)和傅里叶变换红外光谱(FTIR)法分析辣椒红素在外源活性氧·O-₂，H₂O₂和·OH以及在POD，CAT和LOX防御体系中的结构变化特征。结果表明，外源活性氧处理后辣椒红素最大紫外-可见光吸收峰均出现蓝移现象，其中·O-₂和·OH处理后产物FTIR谱峰数减少，峰强变弱，峰形变宽;与色素分子中的羰基和环外烯基发生氧化反应生成烷基和羟基，·OH对色素分子CC具有加成作用;H₂O₂处理后色素特征峰和强势峰均向低波数位移，产物中含环氧醚基团;在H₂O₂+CAT/POD防御体系中辣椒红素UV-Vis和FTIR光谱特征无明显变化;在亚油酸+LOX体系中色素分子结构发生断裂，产物不含羰基。可见活性氧处理及在LOX底物体系中，辣椒红素分子反应前后UV-Vis和FTIR等光谱特征发生明显变化，色素分子中长烯链断裂，大共轭体系缩短或被破坏，分子中的共轭双键和羰基等发色基团改变，最终生成醇类或醚类等小分子无色物质;而防御酶CAT和POD能减少活性氧对辣椒红素分子的破坏作用。研究结果丰富完善了辣椒色素理论，同时为其开发利用提供了有价值的技术参考依据。

Spectral Characterization for Capsanthin Molecule with in Vitro Oxidative Defense Reaction

The changes of UV-Vis and FTIR spectroscopic properties for capsanthin before and after reaction with exogenous superoxide anion(·O-₂), hydrogen peroxide(H₂O₂) and hydroxyl radical(·OH), catalase(CAT), peroxidase(POD) and lipoxygenase(LOX) were explored. The results showed that, the UV-Vis spectral absorption of capsanthin treated with reactive oxygen species had a blue-shift. At the same time, the FTIR spectra changed significantly. The number of FTIR spectral peaks reduced and theFTIR strength weakened for capsanthin molecule treated with ·O-₂ and ·OH. The characteristic and strong peaks moved to shorter wavelengths when treated with H₂O₂. And LOX caused breakage of capsanthin molecule and reduction of peak number or groups without carbonyl. Exogenous H₂O₂+CAT or H₂O₂+POD treatment could not affect the UV-Vis and FTIR spectra significantly. So ROS could cause oxidative degradation of capsanthin and destroy chromophoric groups such as carbon-carbon double bond and carbonyl, then grow colorless alcohols. Hence ROS and LOX should transforms the conjugate system of capsanthin molecules, while CAT and POD could protect the capsanthin.