THE KINETICS OF THE AUTOXIDATION OF POLYUNSATURATED FATTY-ACIDS
THE KINETICS OF THE AUTOXIDATION OF POLYUNSATURATED FATTY-ACIDS
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DOI：
10.1007/bf02533996
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发表时间：
1987-05-01
期刊：
影响因子：
1.9
通讯作者：
PRYOR, WA
中科院分区：
文献类型：
--
作者：
COSGROVE, JP;CHURCH, DF;PRYOR, WA
本文研究了一系列不饱和度递增的多不饱和脂肪酸（PUFA）和亚油酸单、二、三甘油酯在37 ℃、760 ℃氧气条件下的均相氯苯溶液中的自氧化动力学。通过偶氮引发剂的热分解引发自氧化，然后测量氧吸收速率。链起始速率通过诱导期法使用α-β-D测定。生育酚作为断链抗氧化剂。测量的氧化性的PUFA是线性依赖于分子中存在的双烯丙基位置的数量。因此，亚油酸酯的氧化性为2.03 × 10 - 4。10-2 M-1/2秒-1/2，二十二碳六烯酸的值大五倍，即10.15 ×10-2 1/2秒所有PUFA研究和单和甘油二酯的自氧化速率与底物浓度和链起始速率的平方根成正比，这意味着这些化合物的自氧化遵循通常的动力学速率定律。甘油三酯的自氧化更复杂，在所有底物浓度下似乎不遵循相同的速率定律。这种偏离通常的动力学速率表达可能是由于低浓度甘油三酯下的脂质聚集。
The kinetics of the autoxidation of a series of polyunsaturated fatty acids (PUFA) with increasing degrees of unsaturation and the mono-, di- and triglycerides of linoleate have been studied in homogeneous chlorobenzene solution at 37 C under 760 torr of oxygen. The autoxidations were initiated by thermal decomposition of azo initiators and followed by measuring the rate of oxygen uptake. The rate of chain initiation was determined by the induction period method using .alpha.-tocopherol as the chain-breaking antioxidant. The measured oxidizabilities of the PUFA are linearly dependent on the number of doubly allylic positions present in the molecule. Thus, the oxidizability of linoleate is 2.03 .times. 10-2 M-1/2 sec-1/2, and the value for docosahexaenoate is five times greater, 10.15 .times. 10-2 M-1/2 sec-1/2. The rate of autoxidation for all PUFA studied and for the mono- and diglyceride is proportional to the substrate concentration and to the square root of the rate of chain initiation, implying that the autoxidation of these compounds follows the usual kinetic rate law. The autoxidation of the triglyceride is more complex and does not appear to follow the same rate law at all substrate concentrations. This deviation from the usual kinetic rate expression may be due to lipid aggregation at low concentrations of the triglyceride.