Abstract: 【Objective】The aim of this study was to explore the conditions for extracting the odor of rabbit meat by supercritical carbon dioxide fluid extraction (SFE-CO₂), to determine the species, components and contents of rabbit meat odor and to provide the database for further deodorization and processing industry. 【Method】 SFE-CO₂ technology was employed to extract the odorants in rabbit meat with Box-Behnken response surface analysis based on single factor experiments, using extraction yield as a target. The odorants of rabbit meat were detected by gas chromatograph in tandem with mass spectrum, with 2, 4, 6-trimethylpyridine (TMP) as an internal standard. Calculating odor active value (OAV) of the detected matters, and combining with gas chromatography olfactory (GC-O) and sensory evaluation, the main contents of rabbit meat odor was determined.【Result】The results of single factor experiment indicated that the extraction yield could reach 97.91% and the peak areas were 1.58×10⁹ when the extraction temperature was 40℃. When the extraction time was 4 hours, the extraction yield and peak areas were 97.83% and 2.42×10⁹, respectively. The extraction rate reached 97.78% with peak areas of 3.78×10⁸ when the extraction pressure was 25 MPa. Among the three factors, the extraction temperature and extraction pressure not only affected the solute diffusion coefficient, but also the density of CO₂ fluid. The diffusion coefficient increased when the extraction temperature was raised, but the extraction yield decreased due to the decreased CO₂ fluid density. Although the density of CO₂ fluid was larger at higher extraction pressure, the compressibility decreased. Hence, the extraction yield decreased due to the reduction of diffusion coefficient and solubility. When the extraction time was too long, the proportion of the odorants was reduced, for some non-volatile compounds were extracted, with the total amount increased. According to the response surface analysis, it was concluded that the optimal extraction temperature, extraction pressure and extraction time were 40.67℃, 25.67 MPa and 3.13 h, respectively, with extraction yield reached 98.01%. And the actual operation showed that the extraction temperature, extraction pressure and extraction time were 40℃, 25 MPa and 3 h, respectively. Under these conditions, the extraction yield was 98.11%. Through quantitatively adding internal standard substance TMP, GC - MS quantitatively analyzed for rabbit meat volatile flavour compounds of five classes, including aldehydes, acids, esters, heterocyclic compounds and hydrocarbons, a total of 38 kinds of flavor compounds. Comparing the five types of matter content: acids ((1 394.25±3.45) μg·kg^-1) > esters ((569.26±1.23) μg·kg^-1) > hydrocarbon ((471.82±1.11) μg·kg^-1) > aldehyde ((168.46±0.97) μg·kg^-1) > heterocyclic ((86.71±0.64) μg·kg^-1). The key odorants of rabbit meat odor were pentanal, hexanal, hexanoic acid and 2-pentyl furan via calculating OAV. Those four materials with liver off-flavor, grass odor, muttony odor and beany odor respectively were regarded as the main bodies of odor in rabbit meat by GC-O. In addition, the extractant showed rabbit meat odor obviously through sensory evaluation.【Conclusion】The method of SFE-CO₂ which provides a new extraction way for researching rabbit meat odor is feasible. The optimal extraction temperature, extraction time and extraction pressure was 40℃, 3 h, 25 MPa. Pentanal, hexanal, hexanoic acid and 2-pentyl furan were preliminarily regarded as the main bodies of rabbit meat odor.

Key words: rabbit meat, odor, supercritical carbon dioxide fluid extraction (SFE-CO₂), gas chromatography mass spectrum (GC-MS), odor active value (OAV), sensory evaluation