## 3 Results and Discussion
### VOCs Analysis  
Table 5 shows the comparison of VOCs relevant contents of different types of chicken breast; 20, 25, and 19 VOCs were detected in the BJY, AA and LH, respectively. VOCs chromatograms of BJY, LH, and AA were showed in Figures S1-S3, respectively. There were no complicated heterocyclic compounds such as pyrroles and pyrazines in this study, which might be related to the lower maturation temperature (60 \({}^{\circ}\)C). Among the VOCs, 5 compounds were detected in all three types of chicken, including1, 3-bis (1,1-dimylethyl)-benzene, heneicosane, tetradecane, 2,4-bis (1,1-dimylethyl)-enol, and hexadecanal. The volatile flavor substances together affect the final sensory quality of chicken meat. [PERSON] [49] found that the volatile compounds in Avanir broilers, fast-da Yellow chicken, and BJY also contained tetradecane and palmaldehyde. It was predicted that tetradecane and hexadecanal were common volatile substances in chicken meat. \begin{table}
\begin{tabular}{c c c c} \hline
**VOCs** & **BJY** & **LH** & **AA** \\ \hline
**Hydrocarbons** & & & \\ (1-Hexadecylheptadecyl)-Cyclohexane & 2.13 \(\pm\) 0.01 & — & — \\
1,3-Bis(1,1-dimylethyl)-Benzene & 12.72 \(\pm\) 0.05 & 17.68 \(\pm\) 0.00 & 0.70 \(\pm\) 0.01 \\
2-Methylhexacosane & — & — & 2.70 \(\pm\) 0.30 \\ (2,3-Dimethyldecyl)-Benzene & 2.27 \(\pm\) 0.01 & — & — \\
2,4-dimethyl-1-Decene & — & 3.82 \(\pm\) 0.00 & — \\
2,4-Dimethyl-Eicosane, & — & — & 0.39 \(\pm\) 0.01 \\
2,6,10,14-Tetramethyl-Pentadecane & — & — & 11.19 \(\pm\) 0.03 \\
2-Methyl-Dodecane & — & 2.45 \(\pm\) 0.01 & — \\
2-Methyl-Hexadecane & — & — & 6.74 \(\pm\) 0.13 \\
2-Methyl-Metrosane & 2.53 \(\pm\) 0.02 & 2.72 \(\pm\) 0.16 & — \\
3-Methyl-Heptadecane & — & — & 5.06 \(\pm\) 0.51 \\
8-Heptyl-Pentadecane & — & — & 2.63 \(\pm\) 0.18 \\
8-methyl-1-Undecene & — & 2.37 \(\pm\) 0.00 & — \\
8-Methyl-Heptadecane & — & — & 1.60 \(\pm\) 0.04 \\ Decyl-Cyclohexane & — & — & 3.85 \(\pm\) 0.04 \\ Decyl-Cyclopentane & — & — & 1.18 \(\pm\) 0.01 \\ Undecyl-Cyclohexane & — & — & 2.19 \(\pm\) 0.03 \\ Dodecyl-Cyclohexane & — & — & 2.03 \(\pm\) 0.11 \\ Eicosane & — & 0.74 \(\pm\) 0.00 & 7.59 \(\pm\) 4.28 \\ Heneicosane & 13.36 \(\pm\) 0.66 & 6.32 \(\pm\) 0.40 & 19.05 \(\pm\) 0.59 \\ Heptadecane & — & — & 6.66 \(\pm\) 0.36 \\ Hentriacontane & — & 5.60 \(\pm\) 0.12 & — \\ Hexadecane & — & — & 4.90 \(\pm\) 0.99 \\ Octadecane & — & — & 3.73 \(\pm\) 0.08 \\ Squalane & — & — & 6.00 \(\pm\) 0.88 \\ Tetradecane & 1.28 \(\pm\) 0.01 & 3.99 \(\pm\) 0.01 & 0.82 \(\pm\) 0.01 \\ \hline \end{tabular}
\end{table} 
Table 5: Comparison of VOCs relevant contents of different types of chicken breast (%). Table 6 shows the quantity and relative content of VOCs in different types of chicken meat. Hydrocarbons, alcohols, and aldehydes were major VOCs in all three chicken samples, and their contribution to chicken flavor varies with the substance threshold [50]. Hydrocarbons were mainly derived from the cleavage of fatty acid alkoxy radicals, and the differences in the contents might be caused by the differences in their precursor fatty acids. The relative contents and types of hydrocarbon compounds in the three muscles were quite different, which were consistent with the previous results of the fatty acid contents. The aroma threshold of hydrocarbons is relatively high, and it is generally believed that they have little direct contribution to the flavor of meat [51]. Alcohols are mainly derived from the oxidation and degradation of lipids, which have pleasant fruity and floral odors [52]. Among them, 1-octen-3-ol has a mushroom-like smell and is the product of arachidonic acid oxidation by lipoxygenase [24], which was detected in both BJY and LH. In this study, the quantity and relative contents of alcohols in BJY and LH chicken were higher than AA chicken. Aldehydes are aliphatic compounds produced by lipid oxidization and thermal degradation [53], which are usually considered to be the major flavor contributors to meat products due to their low thresholds [54].