RETARDED OXIDATION OF LIQUID LIPIDS ENTRAPPED IN MATRICES OF SACCHARIDES OR PROTEINS

Methyl linoleate (ML), linoleic acid (LA), and ethyl eicosapentaenoate (EE) were entrapped in saccharide and protein matrixes, and then stored at 37-degrees-C in a desiccator controlled at 75% relative humidity. ML entrapped with alpha-cyclodextrin, maltodextrin, and pullulan was extremely resistant to autoxidation, but LA entrapped with maltodextrin and pullulan rapidly oxidized. LA entrapped with alpha-cyclodextrin was the most stable against oxidation. ML entrapped with gelatin or gum arabic was less resistant to autoxidation than that that entrapped with pullulan. there was little difference in the susceptibility to oxidation between ML and LA entrapped with gelatin or gum arabic. Egg albumin protected ML more effectively against oxidation than LA, while sodium caseinate protected LA more than ML. Ethyl eicosapentaenoate entrapped with pullulan was highly resistant to oxidation, 90% of the total lipid remaining after 35 days. The effect on the oxidation of diffusion of oxygen through the matrix was estimated. It is suggested that the retardation of oxidation of the entrapped lipid can not be explained only by the effect of diffusion.