Detection of adulteration

Abstract

A program of work is in progress to establish the levels and ranges of fatty acids and other components present in the major edible vegetable oils. Authentic samples from the major producing areas for such oil have been obtained and analyzed. In the case of palm oil, ranges of the fatty acid composition and of the acids at the triglyceride 2‐position, have been obtained for about 40 samples. These data were used to calculate enrichment factors, and triglyceride carbon number compositions, using a small computer program. Comparison with experimentally determined carbon number compositions were then made. Good correlations were found for whole unadulterated oils, but not for oil fractions. Unfortunately, these differences were insufficient to detect contamination of palm oil by 10 or 20% levels of other oils, or of palm fractions. Compositional ranges of sterols and tocopherols have also been determined on a selection from the original set of palm samples. Work on sunflower seed and groundnut oils has followed the same lines, particular attention having been paid to linolenic acid and, in the case of groundnut oil, also erucic acid, levels. Some groundnut kernels were found to have an oil with a component which cochromatographed with methyl erucate during fatty acid determination. This unknown constituent was studied by gas chromatography‐mass spectrometry, and is thought to comprise a mixture of epoxy fatty acids. Analysis of the triglyceride fraction isolated from groundnut oil by thin layer chromatography removes this unknown constituent, and simplifies interpretation of the fatty acid composition of groundnut oil.

Assessment of Total Lipid Fractions and Fatty Acids Composition in Raw, Germinated Barleys and Talbina Products

“…The methyl esters of fatty acids were prepared from aliquots of total lipids using 5 ml 3% H 2 SO 4 in absolute methanol and 2 ml benzene as described by (Rossell et al, 1983). …”

“…Peak identifications were established by comparing the retention times obtained with standard methyl esters. The areas under chromatographic peak were measured with electronic integrator as mentioned by (Rossell et al, 1983). …”

Application of Chromatographic and Infra-Red Spectroscopic Techniques for Detection of Adulteration in Food Lipids: A Review

“…There are many reported cases of adulteration practices for highly priced vegetable oils and fats such as virgin olive oil, cocoa butter etc. [1][2][3][4]. As extra virgin olive oil is a premium-product, which is short in supply and high in demand, there has always been temptations for its adulteration with cheaper oils [5] or other sub-branded olive products such refined olive oil and olive pomace oil [6].…”

“…As there has been a huge influx of information on food authenticity, many attempts were made time to time to present reviews on this area. As early as nineteen eighties, Rossell and co-workers [4] summarized different classical approaches for detection of adulterations in oils and fats. Rossell [17] also discussed the criteria for determining the purity of selected edible vegetable oils using both classical and modern instrumental approaches.…”

FTIR spectroscopy combined with chemometrics for analysis of lard adulteration in some vegetable oils Espectroscopia FTIR combinada con quimiometría para el análisis de adulteración con grasa de cerdo de aceites vegetales

“…The adulteration of fats and oils is not easy to detect when the oil adulterant has a composition approaching with that of the original oil (Rossell, King, & Downes, 1983). Most initial researches conducted to analyze the oil adulterant involved a time consuming and laborious processes such as wet chemical methods and chromatography techniques.…”