Effect of various microwave treatment parameters on the production of aldehydes in oil

Abstract

It is necessary to study the formation of aldehydes in oil at high temperature. Different from the traditional heating mechanism, microwave heating is widely used, and its effect on aldehydes is also noteworthy. In this paper, we mainly investigated the changes of volatile and non-volatile aldehydes in high oleic sunflower oil (HOSO) under various microwave powers and treatment times. The findings indicate that the oil heated by microwave produces more than 20 volatile aldehydes and 4 non-volatile aldehydes (glycerol ester core aldehydes, GCAs). Hexanal, nonanal, (E)− 2-heptenal, (E)− 2-decenal, and (E,E)− 2,4-decadienal were higher in volatile aldehydes content, while GCAs gradually grew as microwave powers and treatment times increased. The GCAs concentration can increase to 0.72 ± 0.07 mg/kg when the oil is treated at 700 W for 30 min, with the content of four GCAs (8-oxo, 9-oxo, 10-oxo-8, 11-oxo-9) being 0.06 ± 0.01, 0.51 ± 0.06, 0.10 ± 0.00, 0.05 ± 0.00 mg/kg. In particular, GCAs (9-oxo) represented the majority of the overall amount of GCAs during the entire procedure.