Degradation mechanism of lipids by the photo-oxidation and the development of application on anti-oxidation technology of lipids

采用鼓泡塔反应器研究了不同条件下角鲨烯在紫外光照射下的氧化反应。对氧化过程中的氧化产物和分解产物进行了定性和定量分析。氧化过程分为过氧化氢缓慢增加的诱导期和过氧化氢快速增加的加速期两个阶段。诱导期的氧化速率随光强的增加而增加，而加速期的氧化速率不受紫外光照射的影响。从脂质自由基链反应模型出发，推导了过氧化氢的生成速率方程，并用速率方程对实验结果进行了分析。在诱导期，过氧化氢的形成速率与过氧化氢浓度无关，表现为光强的函数；在加速期，过氧化物酶的形成速率表现为过氧化氢浓度的一级反应。用配有化学发光和UV/Vis检测器的高效液相色谱系统对产生的过氧化氢进行分析。从角鲨烯的氧化产物中检测到六种过氧化氢。随着氧化的进行，过氧化氢产物变成酮、醛、脂肪酸和它们的聚合物。

The oxidation reaction of squalene was investigated using a bubble column reactor under the various conditions either with or without UV irradiation. Oxidation products and decomposition products during the oxidation were also qualitatively and quantitatively analyzed. For the oxidation, two stages which are an induction period with a slow increase in hydroperoxide and an accelerated period with rapid increase are observed. The oxidation rate in the induction period increases with photo intensity, however, the rate in the accelerated period is unaffected by the UV irradiation. The formation rate equation of peroxide is derived from the chain reaction model of lipid radical and the experimental results are analyzed using the rate equation. The formation rate of the peroxide is independent on the peroxide concentration and expressed as a function of photo intensity in the induction period, and is expressed by the first order for the peroxide concentration in the accelerated period. The peroxide produced was analyzed by a HPLC system equipped with chemiluminescence and UV/VIS detectors. Six kinds of peroxide are detected as oxidation porducts from squalene. As the oxidation proceeds, the peroxide products are changed to ketones, aldehydes, fatty acids and their polymers.