29B-36 |
Use of WPI, casein, and metal chelators to increase the oxidative stability of algae oil-in-water emulsion at pH 3 |
J. ALAMED, D. Djordjevic, D. J. McClements, and E. A. Decker. Dept. of Food Science, Univ. of Massachusetts, Amherst, Chenoweth Lab., Box 31410, Amherst, MA 01003-1410 Consumption of w-3 fatty acids is beneficial for human health. Because incorporation of w-3 fatty acids into functional foods is limited by their high susceptibility to oxidative degradation, they could potentially be delivered into functional foods in the form of oxidatively stabile emulsions. Protein-stabilized emulsion at pH 3, below the pI of the protein, produces cationic emulsion droplets which inhibit oxidative degradation. Our objective was to evaluate oxidative stability of algae oil-in-water emulsions stabilized by whey protein isolate (WPI) and casein, and to examine the ability of various chelators to inhibit lipid oxidation. Oil-in-water emulsions containing 25 wt % algae oil and 2.5 wt % WPI or casein at pH 3 were prepared by homogenization. Emulsions were pasteurized in a water bath at 75oC for 30 min. Different concentrations (0-100 mM) EDTA or sodium citrate were added to algae oil-in-water emulsions stabilized by WPI. All emulsions were stored at 37oC and particle size and creaming were observed to follow physical stability of the emulsions and lipid hydroperoxides and headspace propanal were measured to follow lipid oxidation. Formation of lipid hydroperoxides was lower in casein-stabilized than WPI stabilized emulsions, however no differences were observed in propanal formation between the two emulsions. Pasteurization at 75oC for 30 min has no effect on the physical or oxidative stability of WPI- or casein- stabilized algae oil-in-water emulsions. Addition of EDTA to the WPI stabilized emulsion decreased lipid oxidation with maximal inhibition observed at 50 mM. Sodium citrate did not inhibit lipid oxidation. Neither EDTA nor sodium citrate altered the physical stability of the WPI-stabilized emulsions. The results suggest that WPI-stabilized emulsions with EDTA were effective at inhibiting the oxidative deterioration of algae-oil-in-water emulsions and could be used to produce w-3 fatty acid emulsion delivery systems for use in functional foods.
Session 29B, Food Chemistry: Lipids, antioxidants and emulsifiers
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