Department of Biochemistry and Food Chemistry, University of Turku, Turku, Finland.
J Agric Food Chem. 2012 Apr 11;60(14):3564-79. doi: 10.1021/jf2050944. Epub 2012 Mar 30.
A normal diet contains large quantities of oxidized fatty acids, glycerolipids, cholesterol, and their cytotoxic degradation products because many foods in the diet are fried, heated, or otherwise processed and consumed often after long periods of storage. There is also evidence that the acid medium of the stomach promotes lipid peroxidation and that the gastrointestinal tract is a major site of antioxidant action, as demonstrated by various colorimetric methods. The identity and yields of specific products of lipid transformation have seldom been determined. The present study describes the molecular species profiles of all major gastrointestinal lipids formed during digestion of autoxidized rapeseed oil in an artificial digestion model in the presence of L-ascorbic acid, 6-palmitoyl-O-L-ascorbic acid, 3,5-di-tert-butyl-4-hydroxytoluene (BHT), DL-α-tocopherol, and DL-α-tocopheryl acetate. Differences in oxidized lipid profiles were detected in the samples digested in the presence of different antioxidants, but none of them could prevent the formation of oxidized lipids or promote their degradation in a gastric digestion model. The lack of effect is attributed to the inappropriate nature of the gastrointestinal medium for the antioxidant activity of these vitamins and BHT. A fast ultrahigh performance liquid chromatographic-electrospray ionization-mass spectrometric method was developed for the analysis of lipolysis products, including epoxy, hydroperoxy, and hydroxy fatty acids, and acylglycerols, utilizing lithium as ionization enhancer.
正常饮食中含有大量氧化的脂肪酸、甘油酯、胆固醇及其细胞毒性降解产物，因为饮食中的许多食物经过油炸、加热或其他加工处理，并经常在长时间储存后食用。还有证据表明，胃的酸性环境促进了脂质过氧化，胃肠道是抗氧化作用的主要部位，这可以通过各种比色法证明。脂质转化的特定产物的身份和产率很少被确定。本研究描述了在人工消化模型中，在 L-抗坏血酸、6-棕榈酰-O-L-抗坏血酸、3,5-二叔丁基-4-羟基甲苯（BHT）、DL-α-生育酚和 DL-α-生育酚乙酸酯存在下，自动氧化菜籽油消化过程中形成的所有主要胃肠道脂质的分子种类谱。在存在不同抗氧化剂的样品中检测到氧化脂质谱的差异，但没有一种抗氧化剂能够防止氧化脂质的形成或促进其在胃消化模型中的降解。缺乏效果归因于这些维生素和 BHT 的胃肠道介质不适合其抗氧化活性。开发了一种快速超高效液相色谱-电喷雾电离-质谱法，利用锂作为电离增强剂，分析脂解产物，包括环氧化合物、氢过氧化物和羟基脂肪酸以及甘油酯。
