RESUMO
Crude extracts were prepared from residues of Rubus glaucus Benth by using food-grade solvents. Their efficacy protecting lipid oxidation of an oil in water (O/W) emulsion as well as of a bulk oil was tested. Stability of lipids during storage of an O/W emulsion was tested by the hydroperoxides and thiobarbituric acid reactive species (TBARS) measurements. Bulk oil stability was measured by the Rancimat method. Fruit pomace crude extracts were the best controlling lipid oxidation of an O/W emulsion, with crude extracts from overripe fruit and bush pruning residues acting as pro-oxidants as measured by the hydroperoxides levels. Neither of the crude extracts was able to inhibit lipid oxidation of the bulk oil. Mathematical modelling revealed that despite total phenolic content and partition coefficient of the crude extracts are important parameters to control lipid oxidation of an O/W emulsion, they do not totally explain their behavior in food-like systems.