 When frying, water can attack the ester linkage of triacylglycerols, resulting in di- and monoglycerols, glycerol, and free fatty acids (a type of hydrolysis reaction).The aforementioned hydrolysis reaction is enhanced by the produced fatty acids and other low molecular weight acid compounds.Overheating or over-using the frying oil leads to formation of rancid-tasting products of oxidation, polymerization, and other deleterious, unintended or even toxic compounds such as acrylamide (from starchy foods).