Influence of ascorbic acid and ascorbyl palmitate on the aroma compositionof an oxidized vegetable oil and its emulsion

The formation of conjugated diene hydroperoxides and hexanal was compared t o the development of aroma profiles during initial lipid oxidation of a veg etable oil and its 40% oil in-water emulsion at 60 degrees C. The aroma pro files of the oil and the emulsion with and without addition of ascorbic aci d or ascorbyl palmitate were compared. The aroma compounds were isolated un der a model mouth system and analyzed by gas chromatography/sniffing port a nalysis. Detectable odors were found and corresponded to 11 and 14 volatile compounds in the oil and the emulsion, respectively. The emulsion had high er lipid oxidation rates than the oil. Addition of ascorbic acid and ascorb yl palmitate had little influence on the aroma composition of the oil. In t he emulsion, addition of these compounds resulted in diminished generation of odor active compounds. Results of measurements of conjugated diene hydro peroxides and headspace hexanal corresponded to that of the lipid oxidation Fate in general, but predicted insufficiently the alterations in the aroma compositions by antioxidants.