Abstract: The volatile flavor components in steamed pork with rice during various processing stages were extracted and identified by dynamic headspace sampling (DHS) combined with gas chromatography-mass spectrometry-olfactometry (GC-MS-O). A total of 79 volatile compounds were identified from raw marinated (intermediate 1), cooked unmarinated (intermediate 2) and cooked marinated streaky pork (intermediate 3) and the finished product. Intermediate 1 showed the highest abundance (2 044.35 g/kg) but the greatest diversity (69) of volatile compounds. Compared with intermediate 2 (2 706.15 g/kg), the amount of volatile flavor substances in intermediate 3 and the product was increased (2 869.79 and 2 900.12 g/kg); however, there was a significant difference in volatile flavor composition. The contents of esters, alcohols, acids and phenols in intermediate 2 were higher than those in three other groups, and the content of aldehydes was lower in the three cooked samples as compared to the raw meat. Principal component analysis (PCA) showed that all four groups were clearly separated; for intermediate 2 and 3, the cumulative variance contribution rate of the first principal component (PC1) was larger, but no significant difference in the cumulative variance contribution rate of the second principal component (PC2) was observed between the two groups. The finished product showed the lowest cumulative variance contribution rate of PC1, which did not significantly differ compared with the other groups, but exhibited a greater cumulative variance contribution rate of PC2, suggesting a great difference in the main flavor composition between the finished product and the intermediates. In general, rice flour has a great influence on the flavor of the product, mainly by inhibiting the generation and release of flavor substances.

Key words: steamed pork with rice, flavor, dynamic headspace sampling, principal component analysis, gas chromatography-mass spectrometry coupled with olfactometry (GC-MS-O)