Organic and non-refined oils

It can be seen that testing for an organic oil could be difficult or impossible. Hydrogenation would be easy to detect but, in the present climate of opinion, is less likely to be used even in non-organic oils. It is possible to test for pesticides, but finding traces would not necessarily invalidate the organic status of the oil, as some pesticides, particularly the polychlorinated ones, persist for many years, and their presence, at low levels at least, would merely show that pesticides had been used on the land at some time, possibly years ago. In any case, intense refining could probably remove any pesticides present, at a cost. The cost would 

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  

Colour. The colour of fully-refined oils is less intense than non-refined oils. Acid and alkaline treatment, and the use of bleaching earths, would all be expected to affect the colour of the oil. The method used could be spectrophotometric or colorimetric. 

Acidity. Steam stripping, bleaching and alkali treatment would all reduce free fatty acids in the oil. 

Tocopherols. Refining, particularly steam stripping and bleaching, does cause loss of tocopherols. However they can be added back, though whether this would be worthwhile is questionable. 

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