Characterization of the key odorants in fried channel catfish based on GC-IMS and GC-MS and investigation of the changes during processing

This study aimed to investigate the changes in the flavor profile of different operational units in preparing prepared catfish products using gas chromatography-mass spectrometry (GC-MS) and GC-ion mobility spectrometry (GC-IMS) techniques combined with statistical analysis. The results showed that channel catfish had different flavor characteristics at different processing stages. Among them, 1-hexanol, acetic acid-methyl ester, and 2-methylbutyric acid-methyl ester were the key volatiles in the curing stage, and octanol was the key volatile compound in the thawing process. These compounds may be connected to the oxidative degradation of 8cC20:1. Pentanone (D), propene, 2,3-pentanedione (D, M), 2,3-butanedione (D), 2-octanone, and phenylethanol are key volatiles during frying, thawing, and reheating. These compounds may be produced by oxidative degradation of C14:0, C14:1, C16:0, C16:1, C17:0, C18:0, 9cC18:1, and C18:3n-6. The butanal, heptanal, nonanal, 2-heptanone (D), 2-hexanone, 1-octen-3-ol, and ethyl acrylate were the key volatiles that were monitored throughout the process. These compounds mainly originated from lipid oxidative degradation. In addition, the reheating stage had the highest free amino acid content, which increased the saltiness and richness. Studying the changes in volatile compounds and their precursors during the processing of the samples improves the theoretical basis for the flavor regulation of pre-fried catfish.