Sterol and stanol-esters prepared with 10 percent molar excess of C4-C24 fatty acids

摘要

Direct esterification of stanols (for example Â-sitostanol) and sterols through the reaction of the stanol/sterol and a fatty acid with a reaction catalyst of less than 0.15% by weight of reaction is described. Suitable catalysts include toluene sulfonic acid, sodium hydrogen phosphate and sodium bisulfite. The acids, or associated salts, include saturated fatty acids of the general formula CH3-(CH2)n-CO2H where n is preferably from 12 to 20. Also included are unsaturated fatty acids for example, oleic, linoleic, linolenic, docosohexanoic, conjugated linoleic acid (9,11-octadecadienoic acid, 10,12-octadecadienoic acid) and mixtures thereof. The fatty acid is present in a 5-10% excess so as to react all of the stanol/sterol or other cholesterol reducing material. The process is limited so that excessive amounts do not need to be removed. The reaction is conducted under vacuum conditions at between 190-230 degrees Celsius to facilitate the removal of water and thereby drive the reaction to completion. No solvents are added to the reaction mixture because the acids act as reactant and solvent. In addition, no toxic solvents or by-products are produced during the reaction. The sterol and stanol-esters have the general formula as depicted in Figure II wherein R1 includes aliphatic straight or branched chain chains with a length of from C4-C24.