ils are fats that are liquid at room temperature. The more polyunsaturated the oil, the more unstable the oil will be. This is because the double bonds in the hydrocarbon chain increase the reactivity of the oil, causing chemical oxidation when exposed to air, light or heat. Oxidised oils become rancid and have a distinctive and repellent taste to them. All oils should be kept in opaque containers to protect them from light, with can decrease the speed that they deteriorate. Keeping the oils cool will also help maintain their freshness, and health giving properties for longer. This is especially true for polyunsaturated oils such as sunflower, flax or hemp, but also is relevant to monounsaturated oils such as olive oil. Oils will react with most types of plastic, and therefore only glass should be used to store oil. Highly unsaturated oils such as might be found in fish oil and safflower oil should be kept in the fridge, even if in capsules.
RdB
