Changes in volatile components of grass carp muscle during crisping process

To study the changes in volatile components of grass carp muscle during crisping process,samples were acquired and measured periodically by solid phase micro- extraction( SPME) and gas chromatography- mass spectrometry( GC- MS),a total of 61 volatile components were identified.The results showed that relative content of alcohols and other kinds increased at crisped breeding 20 d,and then decreased during the crisping process of grass carp. Before crisped breeding 40 d,the relative content of alkanes increased,whereas aldoketones decreased,but the relative content was still higher.After 40 d,the relative content of the former decreased greatly and remained in a very low level at 100 d,whereas the later increased greatly and remained in a very high level at100 d.Aldoketones were the major effects to the flavor of grass carp muscle,the higher contents of nonanal and 2,3- Octanedione were 18.18% and 32.12% in common grass carp,respectively.By the end of crispness,the contents of those decreased to 5.45% and 12.71%,respectively,while the content of hexanal was 65.52%. Besides,other kinds of volatile components were considered lower effect on flavor due to their high odor thresholds or low contents.