Microwave and Conventional Heating Effects on Thermoxidative Degradation of Edible Fats

Abstract

The effects of microwave treatments on the thermoxidative degradation of five edible fats and oils (sunflower oil, high oleic sunflower oil, virgin olive oil, olive oil, and lard) were determined. The samples were subjected to the following three well-controlled treatments: (a) microwave heating, (b) heating in a conventional electric oven, and (c) exposure to microwave energy without heating. A comparative study was carried out on the deterioration of the oils as a result of microwave and conventional oven heating. Degradations were quantified by means of a combination of chromatographic techniques and related analytical index. Data analysis showed greater alterations in microwave-heated samples than in corresponding samples heated in a conventional oven. Finally, microwave energy, without heating (temperature lower than 40 °C), produced no oil alterations. Keywords: Microwave energy; conventional oven; heating effect; edible fats and oils; thermoxidative alteration