[Analysis of volatile compounds in bighead carp by microwave. Distillation and solid phase microextraction coupled...

A technique for the analysis of flavour compounds from fish muscle employing microwave distillation (MD), solid phase microextraction ( SPME) coupled with gas chromatography-mass spectrometry (GC-MS) and olfactometry is described, and 53 compounds responsible for the aroma of bighead carp were identified from NIST 02 MS data base. The extraction of microwave distillation was developed by optimizing the flow rate of carrier gas, heating time and power. Solid phase microextraction procedure was optimized by using different kinds of fiber for the qualitative determination of the volatile compounds observed in the headspace of microwave distillation, including extraction time, temperature, magnetic stirring speed and desorption time in GC-MS equipment. Furthermore, a simple data acquisition and processing system was developed by using human nose as a sensitive detector for the identification of flavour arid off-flavour key compounds in fish tissue. The result showed that the components associated with fish flavour were mostly 6 - 9 carbon aldehydes, ketones and alcohols. According to the olfactory analysis, these compounds were characterized by grassy, fishy, earthy or muddy odors separately, and their synergistic actions were forming the distinct fishy and earthy odors of bighead carp. The rapid method developed by this study may be applied to quantitative analysis of the volatileoff-flavour compounds in fresh-water fish.