This blog is a reminder of which fats to use for cooking and which ones are best used cold in salad dressings. It also covers which ones to avoid.
Fatty acids are classified according to the presence and number of double bonds in their carbon chain. Saturated fatty acids (SAFA) contain no double bonds, monounsaturated fatty acids (MUFA) contain one, and polyunsaturated fatty acids (PUFA) contain more than one double bond.
This table above shows the fatty acid composition of various culinary oils.
You can see from the table above that oils tend to be classified according to their largest constituent. We need to cook with oils which are stable when heated and therefore have a high smoke point. The more double bonds a fatty acid has, the more unsaturated and unstable it will be, especially when heated.
The most stable fats are solid at room temperature, so lard etc. Olive oil (virgin/extra virgin) is pressed straight from the seed or fruit without further refining. There is research to show that the phenols in unrefined olive oil protect it from degradation during cooking (Ramirez-Anaya, 2015).
Oils such as rapeseed, sunflower and vegetable are obtained by washing and crushing the seeds, and then using processes such as heating, hexane, solvents, extraction, processing, bleaching, deodorization and peroxide to maximise production volume. As these oils are highly unsaturated (many double bonds) the risk of oxidation from processing is high, either during processing or if used to cook with. Most of these oils are also much higher in omega-6 than omega-3. As our diets tend to be more deficient in omega-3, I focus on hemp and flax (small amount) which have a 4:1 and a 0.3:1 ratio respectively (o-6:o-3) to try to redress this. I also advocate cold pressed and organic versions to preserve quality and nutrient content.
The following table is a guide Whether you wish to cook with animal fats will depend on various criteria including your health and dietary preferences as well as your ability to digest and absorb fat.
REFS: Del Pilar Ramírez-Anaya, J. et al (2015) Phenols and the antioxidant capacity of Mediterranean vegetables prepared with extra virgin olive oil using different domestic cooking techniques. Food Chemistry Vol 188; pp. 430-438.
