Palm adulteration, detection

With its development, HPLC was found to be useful in many authenticity determinations, either for the same or different components to those detected by GC. Triglycerides were the most immediate application. With the exception of milk fat, now that the major components of commercial fats can be completely separated by HPLC, the patterns of components can be analysed to detect adulteration. Cocoa butter adulteration with palm fractions can be detected by the presence of excess monounsaturated and diunsaturated components from the palm fraction, while more sophisticated products may be detected by measuring dipalmitoyl-monooleoyl glycerol (POP), palmitoyl-oleoyl-stearoyl glycerol (POS) and distearoyl-monooleoyl glycerol (SOS) components. In other oils, apart from the pattern of components, the presence of any significant level of... 

Non-refined oils are easier to detect and authenticate than organic oils, though the absence of a small percentage of some refined oil in the product would be difficult to prove. Where unrefined palm oil was adulterated with rapeseed has already been described above. Where an oil is authentic as to its source, but possibly at least partially refined, in order to check its authenticity, it would then be necessary to build up a database of the expected ranges of values for refined and non-refined oils. Chemical and physical techniques that should be checked are ... 

In some cases, analysis of tocopherols can be used to detect adulteration of oil. Both palm oil and grapeseed oil are relatively unusual in containing significant levels of tocotrienols, which are absent or present at much lower levels in most vegetable oils (Table 6.3). Detection of these compounds can be used to identify adulteration in olive oil at levels as low as 2% (Dionisi et al., 1995). 

Because of its high nutritional value and the beneficial effects that some of its compounds exert, the price of VOO is relatively higher if we compare it with other edible oils. This fact could explain why so many adulterations have been found for VOO this matrix is susceptible to adulteration with cheaper olive oil categories (olive oil pomace, refined olive oil) and/or other edible oils. Com, cottonseed, canola, palm, peanut, soybean, and sunflower oils have been detected in adnlterated VOOs. 

In one study, attempts were made to adulterate virgin coconut oil with palm kernel olein. The study was conducted to evaluate the effectiveness of FTIR spectroscopy in detecting adulteration of virgin coconut oil. As adulterant was used palm kernel olein because of its similarity with virgin coconut oil in chemical composition (Manaf et al., 2007. 

Discriminant Analysis was carried out for pure virgin coconut oil and the blended samples and a classification into two groups, pure virgin coconut oil and adulterated oils was observed. The model demonstrated the classification of pure virgin coconut oil with addition of 1-50% of palm kernel olein usinglO principal components. Therefore, detection of adulteration was possible down to 1%. 

The potential use of electronic nose in detecting adulteration in virgin coconut oil was studied by Marina et al., 2010. An electronic nose (zNose ) was applied to the detection of adulteration of virgin coconut oil. The system is based on a surface acoustic wave sensor. Virgin coconut oil was mixed with refined, bleached and deodorized palm kernel olein at a level of adulteration fi-om 1 to 20% (weight/weight). 

Marina A. M., Man Y. B. C., Amin I. (2010). Use of the SAW sensor electronic nose for detecting the adulteration of virgin coconut oil with RBD palm kernel olein. J Journal of the American Oil Chemists Society 87,263-270. 

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