Comparison of Microwave and Conventional Frying on Quality Attributes and Fat Content of Potatoes.

Abstract

A comparative analysis of quality attributes (moisture, fat, color, and relaxation modulus) of French fries was performed between conventional and microwave frying. Experiments were performed in triplicate for both frying operations at temperatures of 177, 185, and 193 °C for frying times of 60, 90, and 120 s. The real-time pressure and temperature profiles at above conditions indicated that during microwave frying, gage pressure had greater magnitudes that lasted longer, and the temperature increased to boiling point of water faster in comparison to conventional frying. Lower magnitude of negative pressure during microwave frying is expected to have caused lower fat content in fries obtained using this method (0.08 g/g solids less at 185 °C and 0.07 g/g solids less at 193 °C) than conventional frying. The lightness parameter (L* ) decreased to a lesser extent in microwave frying than in conventional frying. The stress relaxation function of the French fries were significantly different between the 2 frying operations. Consumer test confirmed that reduced fat uptake during microwave frying did not compromise with desirable quality attributes of French fries. X-ray micro-computed tomography scanning provided complementary understanding about differences in microstructural properties of fries made using microwave and conventional frying.