30A-4 |
Ability of surfactant micelles to alter antioxidant partitioning and lipid oxidation in oil-in-water emulsions |
W. CHAIYASIT1, M. P. Richards, D. J. McClements, and E. A. Decker. (1) Food Science, University of Massachusetts, Chenoweth Laboratory, Amherst, MA 01003 Most food emulsions contain excess surfactants resulting in the formation of surfactant micelles. These surfactant micelles can solublize components of the lipid droplets into the continuous phase. Therefore it is possible that chain-breaking antioxidants could be removed from the emulsion droplets thus, decreasing the oxidative stability of the emulsion droplet. Our objective was to evaluate the ability of surfactant micelles to influence the physical location of propyl gallate (PG), tertiary butylhydroquinone (TBHQ) and butylated hydroxytoluene (BHT) in oil-in-water emulsions. The influence of micelle solubiliztion of TBHQ on lipid oxidation in salmon oil emulsions was also determined. Phenolic antioxidants in oil were sonicated with aqueous solutions of Brij 700. Partitioning of phenolics was determined spectrophotometrically after separation of continuous phase and lipid droplets by centrifugation. Lipid peroxides and headspace propanal were used to follow lipid oxidation. Solublization of the phenolic antioxidant into the continuous phase by Brij 700 micelles was in the order of PG > TBHQ > BHT. Antioxidant solubilization increased with increasing micelle concentration (0.5-3.0%). At 0.5% Brij 700 in the salmon oil emulsions, TBHQ had no activity at 30 mmol/kg emulsion, was antioxidative at 60 mmol/kg emulsion and was prooxidative at 120 mmol/kg emulsion. At 3.0% Brij 700, increasing TBHQ increased the oxidative stability of salmon oil emulsions (120>60>30>0 mmol TBHQ/kg emulsion) as determined by both lipid peroxides and headspace propanal. These results indicate that surfactant concentration could be an important determinant in the physical location of chain-breaking antioxidants and in the oxidative stability of oil-in-water emulsions.
Session 30A, Food Chemistry: Lipids
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