Thermal Decomposition of BHA in Oil, and the Preventive Effects of Gallic Acid

Abstract

Thermal decomposition of added butylated hydroxyanisole (BHA) in oil and effects of gallic and thiodipropionic acids on decomposition of BHA were investigated. Oils (olive, coconut, soybean and corn oils) containing BHA, gallic acid and a mixtures of BHA and gallic acid were heated in a Pyrex glass tube (2.7cm×20.0cm) at 180°C using an oil bath. Residual BHA was determined by HPLC. The degree of thermal decomposition of BHA in oils was observed to be much higher in olive and coconut oils than in soybean and corn oils, and thermal decomposition of BHA in methyl esters of fatty acid was reduced in the order of stearate>oleate>linoleate. Thermal stability of BHA 2-isomer was higher than that of BHA 3-isomer. Decomposition of BHA in oil was apparently promoted by the addition of oxidation products (oxidized fatty acids: fatty acids insoluble in petroleum ether) of oil. But the addition of gallic and thiodipropionic acids suppressed the thermal decomposition of BHA by oxidized fatty acids.