Lipid changes and volatile compounds formation in different processing stages of dry-cured Spanish mackerel

Abstract This study delves into the alterations in lipids and major flavor compounds occurring throughout various drying stages (raw fish, dry-cured for 4 d, 8 d, and 12 d) of dry-cured Spanish mackerel (DCSM) and elucidates the mechanism behind their formation. The findings exhibit a notable reduction in phospholipid (PL), triacylglycerol (TAG), heptanal, t-2-hexenal, and dimethyl disulfide contents in the samples observed four days before processing. The peroxide value (POV) and thiobarbituric acid reactive substances (TBARS) witnessed a significant surge after 4-8 days, concomitant with the generation of numerous volatile compounds, encompassing alcohols, aldehydes, and ketones. Substantial quantities of 2-methylbutyraldehyde, thiazole, butyl acetate, and trimethylpyrazine emerged during the 8-12 days processing phase. Furthermore, C18:1n-9, C20:5n-3, and C22:6n-3 demonstrated noteworthy correlations with the development of 21 compounds. Principal Component Analysis (PCA), grounded in lipid and volatile compound content, adeptly classified the DCSM drying process into lipolysis and flavor preparation (0-4 d), lipid oxidation and flavor formation (4-8 d), and maturation (8-12 d). The ripening stage played a crucial role in shaping the comprehensive flavor profile. This study offers valuable insights to enhance the traditional DCSM flavor processing and regulation.