Abstract: This study investigated the quality changes and aroma formation in cured grass carp during traditional sun drying processing. For this purpose, aerobic plate count (APC), total volatile basic nitrogen (TVB-N) content, acid value (AV), peroxide value (POV), thiobarbituric acid (TBA) value, color, texture, fatty acid composition as well as volatile flavor components were analyzed. The results showed that APC and TVB-N values of curded fish samples both increased with the expansion of sun drying time, reaching the maximum values of 4.73 (lg (CFU/g)) and 28.39 mg/100 g after four days, respectively, which shows the safety of cured fish products. In addition, with the increase of sun drying time, both AV and TBA values increased consistently, while POV increased at first and then decreased. According to the results of color and texture, the brightness of cured fish fell, while the redness and yellowness became higher during the sun drying processing. At the same time, the hardness and chewiness increased, likely contributing to the unique ‘dry’ aroma of cured fish. After 4 days, the relative percentage of polyunsaturated fatty acids (PUFA) in various lipid components obviously decreased in the following order: free fatty acids > phospholipids > triglycerides. A total of 70 volatile compounds belonging to 7 chemical classes were identified in cured fish samples, out of which 14 odor-active compounds including hexanal were selected. The summation of odor activity value (OAV) of volatile compounds increased from an initial level of 156.67 (salted fish without drying) to 252.88 after the completion of the sun drying, indicating that sun drying treatment may be crucial to aroma formation in traditional cured fish products. This study could provide a theoretical basis for improvement of the traditional production process of cured fish.

Key words: cured fish, sun drying processing, quality change, aroma formation, lipid oxidation