Evaluation of the infrared frying on the physicochemical properties of fried apple slices and the deterioration of oil.

The influence of infrared frying (IF) on the physicochemical properties of fried apple slices and the oil deterioration was investigated, considering conventional frying (CF) as a reference. IF had a more favorable impact on the heating rate and thermal efficiency, which subsequently resulted an accelerated moisture removal rate. The oil uptake in infrared-fried apple slices were reduced by 12.9%-17.3%, when compared to the CF, as attributed to the denser and smoother morphological microstructure. The color of apple slices was better preserved in IF and the total phenolic and flavonoid contents had a higher retention rate with the optimal infrared power (2000 W in this study). Additionally, infrared frying was proved to be a promising technology to slow down the oil deterioration rate as was observed from lower values of acid value, and carbonyl value, which was also supported by the results of gas chromatography, FT-IR, and LF-NMR analysis.