of our action desirable probably open and oil in the two are not really linked, in this context. Olive oil may decompose at a lower temperature than rapeseed oil, but their double bonds will have roughly the same susceptibility to oxidation and thermal decomposition.
According to McCance and Widdowson's 'The composition of food' olive oil has 73% monounsaturated (mostly oleic acid esters C18:1) and 12% polyunsaturates (mostly C18:2). That means for 100 molecules, there are 3 times 73 plus 3 times 12 times 2 double bonds, making 285 double bonds in all. For rapeseed oil, it has 60% monounsaturated (18:1, 20:1 and 22:1 esters) 23% 18:2 and 10% 18:3 (the last two are omega 3 and 6 fatty acid esters, essential for a healthy diet, we are told). This gives 438 double bonds per 100 molecules. So apart from providing omega 3 and 6 fatty acid esters, it may also break down easier in the body.
healthiest cooking oil 345well, one would have to define 'best'. IMHO best for salads-mayo -- olive oil, best for frying-curries --rapeseed oil. I'm not sure smoke point and 'decompose' are the same thing, I think maybe...
healthiest cooking oil 347posted on 1 Nov 2005 by The Reid I would like to add: Mustard oil was discussed in some depth not long after uk.food+drink.indian started, summary...
As regards the cholesterol point, studies have suggested that unsaturated fat may reduce LDL-cholesterol (the artery blocker) and increase the HDL-cholesterol levels in the blood, reducing the LDL-cholesterol. I do not know whether olive oil or rapeseed oil would be better, in this respect, but I know that either in our diets is welcome, and that the rapeseed oil contains the valuable (and necessary) omega 3 and 6 fatty acids, which is why I shall continue to use it for higher temperature cooking. And although linseed oil and walnut oil contain even more omega 3 and 6 FA esters, they also deteriorate very quickly once the bottle (of pure oil) is open, because of the extra double bonds. HTH cheers Wazza
