ISO 11702:2009 specifies a method for the quantitative determination of the total sterols content by means of an enzymatic staining test. The method is applicable to free and esterified sterols in animal and vegetable fats and oils, fatty foods and related products. The determination is applicable to sample quantities of 1 g to 2 g of fat.
The method is not applicable to dark coloured fats and oils, e.g. crude palm oil. The enzyme is not specific for cholesterol, but also oxidizes other 3-hydroxysterols. The method has not been tested for products fortified with sterols at higher levels.