Patent GB-625683-A (GB)
Title: Improvements in or relating to glyceridic fat and oil compositions
IPC: C11B5/00
Filed: 1946-07-31
Abstract: The deterioration of glyceridic fats and fatty oils (including hydrogenated fatty oils), particularly with regard to the development of rancidity and/or off-flavour during storage, is inhibited by incorporating in the oil a monoaliphatic ester of citric acid, obtainable by esterifying a carboxyl group of citric acid.  The glyceridic oil may have been deodorized or hydrogenated and deodorized prior to the incorporation of the citric acid mono-ester and the latter may be a monoalkyl or a monoalkylene ester.  The monoaliphatic ester may be dissolved in a solubilizing agent prior to its incorporation in the oil and this agent may be a di- or trialkyl or alkylene ester of citric acid, an oil-soluble aliphatic alcohol having at least six carbon atoms in the molecule, a monocarboxylic acid having at least ten carbon atoms in the molecule or the monoglyceride of a monocarboxylic acid in which the acyl group has at least ten carbon atoms.  The monoacyl glycerides may be monostearyl glycerides, mono-oleyl glycerides, monomyristyl glycerides, monolauryl glycerides, monopalmityl glycerides or a mixture of two or more of these glycerides.  The aliphatic alcohol may be 2-ethyl hexyl alcohol, n-octyl alcohol, stearyl alcohol, cetyl alcohol or myristyl alcohol.  The monocarboxylic acid may be stearic acid, palmitic acid, oleic acid, lauric acid or myristic acid.  The di- or trialkyl or alkylene ester of citric acid may be produced using the same esterifying alcohol as that used to produce the monoaliphatic ester of citric acid, which may be monoisopropyl or monostearyl citrate. The glyceridic oil may be hydrogenated, deodorized soya bean oil, a shortening or an aqueous and fatty system such as margarine, or lard. The proportion of monoaliphatic citric acid ester in the fat &c. may range from 0.01 to 10 per cent.  In an example, one gram of monoisopropyl citrate is dissolved in 5 grams of monoacyl glycerides prepared from a winterized, refined, undehydrogenated, but deodorized corn oil, and the solution uniformly dispersed in 10 kg. of the corn oil by agitation at 35 DEG  to 50 DEG  C.  Examples are also given of edible oil compositions containing mono-stearyl, or mixtures of mono-stearyl and mono-oleyl citrates, or mono-ethyl citrate.  The preparation of these citrates and of mono-acyl glycerides derived from corn oil, mixtures of mono-, di- and tristearyl citrates, mixtures of mono-, di- and tri-isopropyl citrate and mono-, di- and triethyl citrate is described (see Group IV (b)).  Other mono-citrates which may be used are n-propyl, n-butyl, crotyl, isobutyl, isoamyl, 2-ethylhexyl, lauryl, myristyl and palmityl citrate.ALSO:Monoaliphatic esters of citric acid, suitable for inhibiting the deterioration of edible oils and fats (see Groups I and III) are prepared by heating alcohols with an amount of citric acid in excess of that theoretically required to produce the monoester. The resulting reaction mixture is extracted either with a solvent which dissolves the monoester, leaving the small amounts of di-acid triesters of citric acid undissolved or with a solvent having a preferential solubility for the di- and tri-esters.  In an example a solution of citric acid in dry pyridine containing concentrated sulphuric acid is heated for several hours with stearyl alcohol.  In another example, equal parts of U.S.P. citric acid and isopropyl alcohol are refluxed to give the monocitrate. Examples are given of preparing mixtures of monooleyl and mono-stearyl citrates with the di- and triesters and of mixtures of mono-, di- and tri-isopropyl and ethyl citrates respectively. The di- and triesters function as solubilisers for the mono-esters.  In an example of the preparation of mono-acyl glycerides suitable for promoting the solution of monoesters of citric and in glyceridic oils and fats, glycerine is reacted with corn oil in the presence of sodium bicarbonate, the proportions of oil and glycerine being such as to produce predominantly the monoacyl derivatives of the fatty acid components of the corn oil.ALSO:The deterioration of edible fats and fatty oils, particularly with regard to the development of rancity or off-flavour during storage, is inhibited by incorporating in the oil a monoaliphatic ester of citric acid obtainable by esterifying a carboxyl group of citric acid.  The edible oil may have been deodorized or hydrogenated and deodorized prior to the incorporation of the citric acid monoester, and the latter may be a monoalkyl or monoalkylene ester of citric acid.  The ester may be dissolved in a solubilizing agent such as a di-or trialkyl or alkylene ester of citric acid (or a mixture of such esters) prior to its incorporation in the oil.  Alternative solubilizers may be monoglycerides of monocarboxylic acids in which the acyl group has at least ten carbon atoms, oil-soluble aliphatic alcohols having at least six carbon atoms in the molecule or monocarboxylic acids having at least ten carbon atoms in the molecule.  The edible oil may be natural, deodorized, or hydrogenated and deodorized soya bean oil, a shortening, an aqueous and oil system such as margarine, or lard and the monoaliphatic ester may be monoisopropyl, monostearyl, monooleyl, monoethyl, n-propyl, n-butyl, crotyl, isobutyl, isoamyl, 2-ethyl hexyl, lauryl, myristyl or palmityl citrate.  Di-isopropyl and tri-isopropyl citrates with or without an additional solubilizing agent may also be present and the latter may be stearic acid.  The proportion of monoaliphatic citric acid ester in the composition may be 0.01 per cent to 10 per cent.  In an example 1 gram of mono-isopropyl citrate is dissolved in 5 grams of monoacyl glycerides prepared from corn oil and the solution uniformly dispersed in 10 kg. of corn oil by agitation at 35 to 50 DEG C. Examples are also given of other edible oil and fat compositions containing other mono-citrates and other solubilizers (see Group III) and the preparation of these and other citrates and solubilizers is described (see Group IV(b)).