Abstract: The volatile flavor components of Tuotuo pork samples from four different producers were investigated by electronic nose (EN) and headspace solid-phase microextraction-gas chromatography-mass spectrometry-olfactometry (HS-SPME-GC-MS-O). Furthermore, principal component analysis (PCA) was carried out on the major flavor components. The results showed that EN combined with linear discriminant analysis (LDA) was an effective method to distinguish the difference in volatile components of different Tuotuo pork samples. By HS-SPME-GC-MS-O, a total of 45 volatile compounds were detected from the samples, mainly aldehydes, alcohols, ketones, olefin, and heterocyclic compounds. Through odor activity value (OAV) calculation and olfactometry, 27 flavor substances with OAV ≥ 1 were identified, eight of which were found in all four samples, including hexanal, heptanal, octanal, (E)-2-heptenal, nonanal, (E)-2-octenal, (E,E)-2,4-decadienal, and 1-octene-3-ol, together contributing to 71.16%–93.12% of the total flavor as the major flavor components. In addition, volatile compounds derived from the seasonings used, including L-carvone, pinene, β-pinene, D- limonene, (E)-β-ocimene, citral, propyl mercaptan, eucalyptus alcohol, and linalool contributed to the remaining 12.71%–28.58%. Based on the 27 flavor components, PCA showed good separation among the samples. Samples C and D scored higher on PC1, while samples A and D scored higher on PC2. The contribution of (E,E)-2,4-decadienal to the flavor of Tuotuo pork was bigger on PC1, whereas the contribution of linalool was the highest on PC2, followed by limonene and 1-octene-3-ol. Therefore, (E,E)-2,4-decadienal, linalool, limonene, and 1-octene-3-ol were the important flavor substances to discriminate among Tuotuo pork from different producers.

Key words: Tuotuo pork; volatile flavor substance; odor activity value; electronic nose; principal component analysis