GB761186A - Antioxidant concentrates - Google Patents

Abstract

An antioxidant concentrate for fats, fatty oils and fatty acids comprises one or more antioxidants and, as a solvent therefor, a reaction product of propylene glycol with mixed glycerides of fatty acids. The reaction produced is believed to be the result of an ester interchange between the glycol and the mixed glycerides. The glycerides used are mixtures in any combinations of mono-, di- and tri-glycerides of fats and fatty oils, such as lard, corn oil or cotton seed oil, prepared, for example, as described in Specifications 682,625 and 682,626 [Group IV(b)]. The solvent reaction products are prepared by heating a mixture of propylene glycol and the desired glycerides, with or without a catalyst and preferably in an inert atmosphere such as nitrogen or carbon dioxide. The ratio of the reactants preferably varies between 1 to 3 moles of propylene glycol to 1 mole of the mixed glycerides. Suitable catalysts comprise sodium hydroxide, orthophosphoric acid and sodium ethoxide. Propylene glycol may be mixed with the solvent. The preferred antioxidants are gallic acid esters and alkylated hydroxyphenyl ethers, used separately or together and with or without a synergizing acid or ester. The preferred gallic acid esters contain as the ester radical an alkyl group of 1 to 12 carbon atoms, and the compounds exemplified include n-propyl gallate and n-lauryl gallate. The preferred alkylated hydroxyphenyl ethers are tertiary butyl or tertiary amyl hydroxyanisoles or hydroxyphenetoles, and the compounds exemplified include 3-tertiary-butyl-4-hydroxyanisole and 2-tertiary-butyl-4-hydroxyanisole. The synergizing acid or ester may be citric acid, monoisopropyl citrate, 2-hydroxypropyl citrate, orthophosphoric acid, tartaric acid or ascorbic acid. The fats, fatty oils and fatty acids, which may be stabilized include lard, palm oil, cotton seed oil and stearic acid.