Abstract: This paper explores the release pattern of aroma from stewed pork with brown sauce at different oral processing stages. A panel of four subjects was selected and trained to freely chew the samples. Breath gas samples were collected using Tedlar? bags at different oral processing stages for qualitative and quantitative analysis of volatile organic compounds by solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). The correlation between the total amount of aroma release and chewing parameters was analyzed, and the pre- and post-swallow distribution of aroma release were compared with each other. Results showed that the aroma release curves (from both a panel and individual perspective) always dynamically changed during oral processing, with an inter-individual difference being observed. Correlation analysis showed that there was a significantly positive correlation between chewing time (r = 0.910, P < 0.01) and the number of chewing cycles (r = 0.851, P < 0.01) and the amount of aroma release. Moreover, the ratio of aroma release was larger at the pre-swallow stage than at the post-swallow stage. The release of three major volatiles with different hydrophobicity (lgP values) were analyzed at the pre-swallow and post-swallow stages, and it turned out that the higher the hydrophobicity of volatiles, the higher the release of aroma at the post-swallow stage. The use of Tedlar? bags combined with SPME-GC-MS provided a novel method for qualitative and quantitative analysis of breath gas from foods during oral processing. This study provides a methodological foundation for the study of the release kinetics of food aromas.

Key words: stewed pork with brown sauce, oral processing, aroma release, volatile organic compounds, swallowing