Changes in volatile compounds of traditional Chinese Nanjing water-boiled salted duck during processing

Volatile compounds of traditional Chinese Nanjing water-boiled salted duck (NJWSD) during its stages of processing were analyzed by headspace solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometer (GC-MS). Results showed a total of 92 tentatively identified volatile compounds of which 57 compounds were first identified in duck meat. The major volatiles identified were degradation products of fatty acids, which were considered to account for the typical flavor of duck meat. The processes of dry-curing, brining, roasting, and boiling, all sped up lipid oxidation and degradation. Dry-curing process generated furans, the important lipid oxidation products. Brining accelerated the formation of S- and N-containing compounds. Roasting had no remarkable effect on most of the volatiles. Some S- and N-containing compounds, such as 2-methylthiophene, dimethyl trisulfide, and 2-acetylthiazole formed during boiling combined with lipid peroxidation and degradation products could constitute the principle flavor of NJSWD. The first principal component (PC1) explained 97% of the total variance of the date and was dominated by lipid oxidation and degradation products, where were pentanal, hexanal, octanal, nonanal, and 2,3-octanedione. The problem using SPME for quantitation was also discussed.