Formation of Volatile Flavor Compounds and Changes in Fat Oxidation in Blunt-snout Bream by Traditional Sun-drying and Shade-drying

In this experiment, blunt-snout bream was used as raw material, and the pickled blunt-snout bream was processed by two traditional drying methods, sun-drying and shade-drying, and by measuring peroxide value, acid value, anisidine value, polydilute index, carbonyl value, fatty acid content combined with the determination of volatile compounds, electronic nose and sensory evaluation to explore the characteristic flavor compounds of dried fish in different traditional drying methods and overall flavor differences. The results showed that the oxidation value, acid value, anisidine value, polydilute index and carbonyl value of blunt-snout bream dried in sunlight were higher than those in the shade-drying and undried groups. The relative content of unsaturated fatty acids in sun-dried blunt-snout bream was lower than that of shade-dried and undried blunt-snout bream, especially oleic acid (C18:1n9), linoleic acid (C18:2n9), and linolenic acid (C18:3n3) were significantly lower. Different drying methods had a greater impact on the overall odor and volatile flavor compounds of blunt-snout bream. The main types of volatile substances produced by the two drying methods were 28 and 23, respectively, and 20 in the wet group. Most of the characteristic flavor substances in sun dried fish were aldehydes and alcohols. Sun-dried blunt-snout bream had stronger halal flavor and meat flavor, shade-dried blunt-snout bream has more pronounced fishy smell and rancidity, and undried blunt-snout bream had a strong fishy smell and fragrance. The correlation results showed that the aroma compounds of blunt-snout bream were positively correlated with fat oxidation, and significantly negatively correlated with typical monounsaturated fat plugs and polyunsaturated fatty acids. Fat oxidation was an important pathway for the formation of aroma in blunt-snout bream, and sunlight promoted fat oxidation, the formation of flavor and aroma accumulation in blunt-snout bream.