Patent ID: 7115253

Claim:
A process for stabilizing antioxidant compounds selected from the group consisting of levogyrous acid (LAA), proanthocyanidines (OPCs) and mixtures thereof, comprising: contacting said antioxidant compounds, in an aqueous medium, with an oxygen-removing compound, a metallic ion sequestering compound and a reducing agent; wherein the oxygen-removing compound is a glycol; further wherein the metallic ion sequestering compound is selected from the group consisting of sodium salt of 1-hydroxy ethylidene (1,1-diphosphate) acid, ethylene diamine tetra(methylenephosphonic) acid, sodium salt of ethylene diamine tetra(methylenephosphonic) acid, diethylene diamine penta(methylenephosphonic) acid, sodium salt of diethylene diamine penta(methylene phosphonic) acid, hydroxyethylidene (1,1-diphosphate) acid and mixtures thereof.