## 3 Results and Discussion
### OAVs and Sensory Attributes
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Compound**} & \multicolumn{2}{c}{**Threshold in Water**} & \multicolumn{6}{c}{**OAVs**} \\ \cline{2-9}  & **from the Literature** & **FAD** & **FSD** & **FFD** & **GAD** & **GSD** & **GFD** \\ \hline \hline
**Alcohols** & & & & & & & \\ \hline Linalool & 0.028 & 6086 & 6254 & 1048 & 2658 & 2399 & 474 \\ Terpinen-4-ol & 6.4 & 3 & 4 & 4 & 6 & 11 & 7 \\ \(\alpha\)-Terpineol & 10 & 11 & 12 & 9 & 16 & 22 & 13 \\ Citronello & 0.062 & 423 & 252 & — & 216 & 227 & 195 \\ Elemol & 0.1 & 235 & 123 & — & 295 & 168 & — \\ \hline
**Aromatic hydrocarbons** & & & & & & & \\
**and ethers** & & & & & & & \\ \hline \(\beta\)-Cymene & 0.8 & 17 & 21 & 13 & 41 & 121 & 35 \\ p-Cymene & 0.665 & — & — & 63 & — & — & 37 \\ \hline
**Phenols** & & & & & & & \\ \hline Thymol & 0.79 & 35 & 35 & 44 & 86 & 94 & 116 \\ Carvacrol & 2.29 & — & — & — & — & 7 & 24 \\
2-Methoxy-4- & vinylphenol & 0.003 & 12,493 & 9028 & 52,323 & 4050 & 4805 & 4883 \\ \hline
**_N-containing_** & & & & & & & \\
**compounds** & & & & & & & \\ \hline Methyl anthranilate & 0.003 & — & — & — & 3919 & 7336 & 7872 \\ Methyl methanthranilate & 0.349 & 694 & 326 & 596 & 9722 & 9674 & 6699 \\ \hline
**Aldehydes** & & & & & & & \\ \hline Furfurral & 3 & 23 & 18 & 26 & 9 & 4 & 13 \\ Benzaldehyde & 1 & — & — & 25 & — & — & 9 \\ Octanal & 0.08 & 157 & 137 & — & — & — & — \\ Decanal & 0.07 & 1125 & 945 & 526 & 546 & 432 & 434 \\ Perillal & 0.03 & 1009 & 1048 & — & 2040 & 2270 & 985 \\ Undecanal & 0.04 & 266 & — & — & 253 & — & 287 \\ Dodecanal & 0.055 & 1462 & 896 & 1205 & — & — & — \\ Tetradecanal & 0.067 & 172 & — & 345 & — & — & 227 \\ \(\alpha\)-Sinensal & 0.22 & 809 & 639 & 311 & 2777 & 1946 & 537 \\ \hline
**Monoterpens** & & & & & & & \\ \hline (-)-\(\alpha\)-Pinene & 0.1 & 131 & 368 & — & 187 & 946 & — \\ (-)-\(\beta\)-Pinene & 4.16 & — & 4 & — & 3 & 17 & — \\ \(\beta\)-Myrcene & 0.099 & 408 & 969 & — & 220 & 875 & — \\ \(\alpha\)-Terpinene & 0.08 & & 203 & — & 166 & 589 & — \\ D-limonene & 1.2 & 1474 & 3000 & 110 & 813 & 2633 & 82 \\ \(\gamma\)-Terpinene & 0.6 & 293 & 637 & 35 & 434 & 1848 & 45 \\ Terpinolene & 0.041 & 569 & 831 & — & 794 & 2277 & — \\ \hline
**Sesquierpens** & & & & & & & \\ \hline (-)-\(\beta\)-caryophyllene & 1.54 & 14 & 8 & 6 & 146 & 139 & 62 \\ \(\alpha\)-humulene & 0.39 & — & — & — & 101 & 73 & 36 \\ \hline \hline \end{tabular} The term “_—_” means the compound was not detected in sample.  
\end{table} 
Table 2: Odor activity values (OAVs) of odorants in dried Citrus peel prepared from different drying methods. late of the highest at 9674, followed by methyl anthranilate at 7336; in GFD, the OAVs for 2-methoxy-4-vinylphenol, methyl anthranilate, and methyl methanthranilate were all beyond 1000, with methyl anthranilate of the highest at 7872, followed by methyl methanthranilate at 6699 and 2-methoxy-4-vinylphenol at 4883. It can be seen that, except for 2-methoxy-4-vinylphenol, methyl methanthranilate and methyl anthranilate also contributed much to the flavor of dried Chachi peel, especially for the sample prepared from AD and SD. Despite of different drying methods, the higher OAVs for 2-methoxy-4-vinylphenol and linalool were observed for dried Ponkan peel while the higher OAVs for methyl anthranilate, methyl methanthranilate, perillal, \(\alpha\)-sinensal, \(\gamma\)-terpinene, and terpinolene were observed for dried Chachi peel. The OAVs indicated that these compounds could differentiate the aroma of dried Ponkan and Chachi peel. Furthermore, for both dried Ponkan and Chachi peel, the highest OAVs for monoterpenes were both observed for the SD, indicating monoterpenes may be the characteristic aroma compounds of SD citrus peel. In addition, although D-limonene was the most abundant compound among the volatile components of citrus fruits, its contribution to the aroma was not so much, in accordance with the literature [41].