Lipid derived free radical in soymilks were studied by combining 5,5-dimethyl-pyrroline-l-oxide (DMPO) spin trap, chloroform-methanol extraction and electron spin resonance (ESR) spectroscopy. Five lipid derived free radical adducts: DMPO-X, DMPO-L, DMPO-R, DMPO-LOO, and DMPO-RO were presented in soymilks. The total amounts of spins increased as the soaking temperature increased from 4 °C to 50 °C and the soaking pH increased from 3 to 9 and in paralleled with the diffusion of soybean exudates to soaking water. Prolonged soaking of soybean at 50 °C resulted in a higher signal intensity of DMPO-R than that of DMPO-LOO. Soybean lipoxygenases (LOXs) were responsible for the formation of lipid derived free radicals in soymilks. Soybean exudates affected the total amounts of lipid radicals in linoleic acid (LA) - LOX model system. The relative signal intensities of DMPO-R and DMPO-LOO were depended on the contents of soybean exudates in the system.

中文翻译：

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浸泡条件对豆浆中脂质自由基形成的影响。


通过结合 5,5-二甲基吡咯啉-1-氧化物 (DMPO) 自旋捕获、氯仿-甲醇萃取和电子自旋共振 (ESR) 光谱研究了豆奶中的脂质衍生自由基。豆浆中存在五种脂质衍生的自由基加合物：DMPO-X、DMPO-L、DMPO-R、DMPO-LOO 和 DMPO-RO。随着浸泡温度从 4°C 升高到 50°C、浸泡 pH 值从 3 增加到 9，自旋总量增加，并且与大豆渗出物向浸泡水中的扩散同时发生。在 50 °C 下长时间浸泡大豆导致 DMPO-R 的信号强度高于 DMPO-LOO。大豆脂氧合酶（LOX）是豆奶中脂质衍生自由基形成的原因。大豆渗出物影响亚油酸（LA）-LOX模型系统中脂质自由基的总量。 DMPO-R 和 DMPO-LOO 的相对信号强度取决于系统中大豆渗出液的含量。