| Abstract: | Differences in the efficiency of antioxidants in dispersed lipid systems may be related to the differential solubility of the antioxidants within the physically distinct phases of colloidal food systems. This study determined the partitioning of antioxidants in water/oil systems, surfactant solutions (dodecyltrimethylammonium bromide, DTABr, sodium dodecylsulfate, SDS, polyoxyethylenesorbitan monolaurate, Tween 20), and emulsions. There were significant differences in the partition of the antioxidants between oil, water and interfacial phases both as a function of pH and surfactant. The proportions of hydrophilic antioxidants (ferulic acid, caffeic acid, gallic acid, propyl gallate, catechin and Trolox) showed significant decreases in the aqueous phase when lowering the pH from 7.0 to 3.0 in Tween 20 emulsions. DTABr lowered the proportion of all antioxidants in the unbuffered aqueous phase to a higher extent than SDS or Tween 20. Changing the ionic strength (5mM NaCl to 50mM NaCl) did not cause significant differences in water/oil systems. Therefore, the effectiveness of hydrophilic antioxidants in heterophasic systems is influenced by their partition into the different phases of water/oil, surfactant and emulsion systems. |
