# Variation in Volatile Flavor Compounds of Cooked Mutton Meathalls during Storage
## 3 Results
### Analysis of Volatile Flavor Compounds in Cooked Mutton Meatballs during Storage
The number of volatile compounds was much higher than that of odor-active compounds, indicating that most of the volatile compounds had no significant effect on the formation of the aroma of cooked mutton meatballs. During the storage of cooked mutton meatballs, the increase and decrease of odor-active compounds and the FD factor are also constantly changing. Compared with the change of FD factor in cooked mutton meatballs during storage, it can be seen that the number of odor-active compounds identified by SPME/GC-O-MS is gradually decreasing. The FD factors of allyl mercaptan (garlic), 1-octene-3-alcohol (mushroom), linalool (loral), diallyl disulfide ether (onion), diallyl trisulfide (onion), \(\alpha\)-pinene (pine), 3-carene (resin), d-cadinene (medicine), unknown (sweet) and ethyl caprate (grape) were higher during the storage period, which contributed to the overall aroma degree of cooked mutton meatballs. However, the FD factors of caryophylene (spice), hexanal (grassy), allyl methyl disulfide (onion), diallyl disulfide (onion), linalool (loral), geraniol (fruity), unknown-(balsam) and butyric acid (sweaty) during the storage were higher SAFE during the storage period, which contributed to the overall aroma degree of cooked mutton meatballs. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**NO.**} & \multirow{2}{*}{**RI**} & \multirow{2}{*}{**CAS No**} & \multirow{2}{*}{**Compound**} & \multirow{2}{*}{**Odor**} & \multicolumn{5}{c}{**FD Factor**} \\ \cline{5-8}  & & & & & **0 d** & **30 d** & **60 d** & **90 d** \\ \hline A1 & 871 & 870-23-5 & Allyl mercaptan & garlic & 243 & 81 & 9 & 9 \\ A2 & 1187 & 470-82-6 & Cineole & mint & 3 & 9 & - & - \\ A3 & 1392 & 3391-86-4 & 1-Octen-3-ol & mushroom & 9 & 9 & 9 & - \\ A4 & 1495 & 78-70-6 & Linalool & floral & 27 & 3 & 3 & 1 \\ A5 & 1834 & 106-24-1 & Geraniol & wavy & 27 & - & - & - \\ A6 & 1262 & 2179-58-0 & allyl methyl disulphide & garlic, onion & - & 9 & - & - \\ A7 & 1454 & 2179-57-9 & Diallyl Disulfide & onion garlic & 3 & 9 & 9 & - \\ A8 & 1754 & 2050-87-5 & Diallyl trisulfide & garlic onion & 243 & 27 & 9 & 27 \\ A9 & 1013 & 80-56-8 & \(\alpha\)-pinene & pine & 27 & 9 & 1 & 1 \\ A10 & 1088 & 127-91-3 & \(\beta\)-pinene & resin & 3 & 1 & 3 & - \\ A11 & 1124 & 13466-78-9 & \(\beta\)-carene & pine resin & 3 & 3 & 3 & 3 \\ A12 & 1188 & 555-10-2 & p-metha-1(7),2-diene & serpentine & 9 & - & - & - \\ A13 & 1214 & 3779-61-1 & trans-Ocimene & sweet & - & 1 & 3 & 1 \\ A14 & 1268 & 586-62-9 & terpinolene & pine & 243 & - & - & - \\ A15 & 1418 & 18368-95-1 & p-methathe, & turpentine & 9 & - & - & - \\ A16 & 1428 & 1195-32-0 & \(\alpha\),para-Dinetlystyrene & citrus & 3 & 1 & 3 & 1 \\ A17 & 1455 & 3856-25-5 & (-)\(\alpha\)-coppene & spicy & 27 & - & - & 9 \\ A18 & 1591 & 515-13-9 & (-)\(\beta\)-Elemene & sweet & 9 & 3 & 1 & - \\ A19 & 1604 & 87-44-5 & Caryophyllene & spice & 3 & - & - & - \\ A20 & 1761 & 483-76-1 & unknown & medicine & 9 & 9 & 1 & 9 \\ A21 & 1256 & 99-87-6 & p-Cymene & citrus & - & - & 9 & 27 \\ A22 & 1701 & 90-12-0 & 1-Methyllnaphthalene & camphor & - & - & 3 & - \\ A23 & 1944 & 120-58-1 & Isoasfrole (Controlled) & sweet & 3 & 3 & 9 & 3 \\  & & & 1,2-Dimethoxy-4- & & & & & \\ A24 & 2001 & 93-15-2 & allybenzene & clove & - & 9 & - & - \\ A25 & 1619 & 110-38-3 & ethyl caprate & grape & 3 & 1 & 3 & 3 \\ A26 & 1639 & 110-93-0 & 6-Methyl-5-hepten-2-one & mushroom & 3 & 1 & 3 & 3 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The result of DHDA of SPME/GC-O-MS.  
Table 5 lists odor-active compounds with OAV values greater than 1 by SAFE and SPME/GC-O-MS. OAV is not only related to the concentration of volatile flavor substances but also to its odor threshold. The greater the OAV value is, the greater the contribution to the whole sample is. It is worth noting that the FD factor of odor-active substances with an OAV value greater than 1 was too low for \(\beta\)-pinene, nonanal, ((1S)-endo)-(-)-borneol and 2-methylnaphthalene.