A description is given of the development by collaborative study of two standardized methods for the determination of polar compounds in oils and fats by adsorption chromatography using silica minicolumns, and for quantification of polymerized triacylglycerols, oxidized triacylglycerols, and diacylglycerols in polar compounds by high-performance size-exclusion chromatography. The first procedure is sensitive, allowing savings in time, solvents, and reagents as compared to the previous determination (Standard Method 2.507), while the second is very rapid, giving a detailed information on the main groups of compounds in fats and oils associated with hydrolysis, oxidation, and thermal polymerization. Both methods are useful for the analysis of used frying fats as well as for the analysis of virgin or refined oils.

Dried microencapsulated oils are powdery foods or ingredients, prepared by drying natural or formulated emulsions, wherein the oil globules are dispersed in a matrix of saccharides and/or proteins. The study of lipid oxidation in microencapsulated oils is a very difficult task since, in addition to the numerous variables normally involved in lipid oxidation, mainly unsaturation degree, oxygen, light, temperature, prooxidants and antioxidants, other factors exert an important influence in these heterophasic lipid systems. In this paper, the present state of the art on lipid oxidation in dried microencapsulated oils is reviewed, focused on the variables specifically involved in oxidation of these lipid systems. Such variables include those pertaining to the preparation process (type and concentration of the matrix components and drying procedure) and those related to the physicochemical properties of microencapsulated oils (particle size, oil globule size, lipid distribution, water activity, pH and interactions between matrix components).