植物油中的碘值、酸值

Unsaturated fatty acids such as oleic acid and linoleic acid contained in fats and oils consume reacting with the double bond in unsaturated fatty acid. Iodine is expressed as “grams equivalent to halogen quantity of double bound (=unsaturated fatty acid) in oils and fats. As iodine bromide (IBr, Hanus method) or iodine monochloride (ICl, Wijs method) is used respectively. This application note describes the Wij’s method. An excessive volume of volume of iodine solution is added to react with existing double bonds quantitatively in one by one ratio. The acid value of oils and fats indicates the level of free fatty acid contained in oils and fats, expressed as milligrams (mg) of potassium hydroxide necessary to neutralize acidic compounds in 1mg of sample. In this method, the sample is dissolved in 100mL ethanol-diethyl ether mixture and titrated with 0.1mol/L potassium hydroxide in alcohol.