Determination of cholesterol oxides in dairy products. Effect of storage conditions
Determination of cholesterol oxides in dairy products. Effect of storage conditions
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DOI：
10.1021/jf970431
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发表时间：
1997-11-01
影响因子：
6.1
通讯作者：
Gil, A
中科院分区：
文献类型：
--
作者：
Angulo, AJ;Romera, JM;Gil, A
建立了乳制品中胆固醇氧化产物（COPS）的气液色谱定量分析方法。根据Folch方法提取脂质，并在室温下使用氢氧化钠的甲醇/苯（3：2，v/v）溶液皂化。胆固醇氧化物衍生三甲基甲硅烷基醚和解决的GLC，确认胆固醇氧化物的结构，在选定的样品中检测到的GLC/MS。这种方法允许快速，简单，可靠的定量游离和酯化胆固醇氧化衍生物。该方法适用于奶粉、黄油和分离乳蛋白粉。研究了全脂奶粉和脱脂奶粉中不利储存条件的影响。即使在温和的储存条件下，储存温度也会严重影响COPS的水平。在氮气下包装延缓胆固醇氧化。在不同储存条件下观察到COPS曲线略有差异。7-酮胆固醇是形成的主要胆固醇氧化物。硫代巴比妥酸反应物质和COPS浓度之间有很好的相关性。
A methodology to quantify cholesterol oxidation products (COPS) in dairy products has been established by gas-liquid chromatography (GLC). Lipids were extracted according to the Folch method and saponified at room temperature using sodium hydroxide in methanol/benzene (3:2, v/v). Cholesterol oxides were derivatized to trimethylsilyl ethers and resolved by GLC, confirming the structures of cholesterol oxides detected in selected samples by GLC/MS. This methodology allows quick, simple, and reliable quantification of free and esterified cholesterol oxidized derivatives. This method was applied to milk powders, butter oil, and isolated milk protein powders. Effects of adverse storage conditions were studied in whole and skim milk powders. Storage temperature severely affected levels of COPS even under mild storage conditions. Packaging under nitrogen retarded cholesterol oxidation. Slight differences in COPS profiles were observed between different storage conditions. 7-Ketocholesterol was the major cholesterol oxide formed. A good correlation between thiobarbituric acid reactive substances and COPS concentration was observed.