An improved method to discover adulteration of Styrian pumpkin seed oil

被引:27
作者
Wenzl, T
Prettner, E
Schweiger, K
Wagner, FS
机构
[1] Graz Univ Technol, Inst Analyt Chem Micro & Radiochem, A-8010 Graz, Austria
[2] Karl Franzens Univ Graz, Inst Pharmaceut Chem, A-8010 Graz, Austria
[3] Inst Reg Prod Dev, A-8403 Lebring, Austria
来源
JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS | 2002年 / 53卷 / 1-3期
关键词
pumkin seed oil; adulteration; phytosterols; trimethylsilylether;
D O I
10.1016/S0165-022X(02)00108-2
中图分类号
Q5 [生物化学];
学科分类号
071010 ; 081704 ;
摘要
Pumpkin seed oil is rather expensive compared to other vegetable oils. Therefore, it is often adulterated by the addition of cheaper oils. In contrast to other edible oils, the content of Delta5-sterols is very low, while Delta7-sterols are dominating. The determination of Delta5-sterols, especially beta-sitosterol has proven to be a good possibility to detect admixture of cheap vegetable oils to a level below which the economic profit is not significant any more. The presented method is a variant of an analysis concept, which has been published previously in-European Food Research and Technology by Mandl et al. [Eur. Food Res. Technol. 209 (1999) 400.]. It includes saponification of the triglycerides as a first step followed by separation of the potassium salts of the fatty acids from the unsaponifiable fraction by adsorption chromatography. In order to enhance gas chromatographic properties of the analytes, the hydroxyl function of the sterols is derivatized with N-Methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) to the trimethylsitylether. Finally, the analytes are separated on a capillary column of medium polarity (HP 35 MS) in a temperature programmed run within 18 min. Detection of the analytes was done by flame ionization. Special attention was set onto the precision and repeatability of the method. (C) 2002 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:193 / 202
页数:10
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