Deterioration of edible oils during food processing by ultrasound.

During food emulsification and processing of sunflower oil (most used edible oil), a metallic and rancid odour has been detected only for insonated oil and foods. Some off-flavour compounds (hexanal and hept-2-enal) resulting from the sono-degradation of sunflower oil have been identified. A wide variety of analytical techniques (GC determination of fatty acids, UV spectroscopy, free fatty acids and GC/MS) were used to follow the quality of insonated sunflower oil and emulsion. Different edible oils (olive, sunflower, soybean, em leader ) show significant changes in their composition (chemical and flavour) due to ultrasound treatment.