# Analyzing Volatile Compounds of Young and Mature _Docynia delavyi_ Fruit by HS-SPME-GC-MS and rOAV
## 3 Results
### rOAV Analysis of Key Volatile Compounds in D. delavyi Fruit of Varying Maturities  
rOAV data for the 14 volatile aroma compounds identified among the 23 key volatile compounds are shown in Figure 5, from which \(\beta\)-ionone and phenethyl acetate were found to mostly contribute to the overall flavor of DY and DM, respectively. Except for \(\beta\)-ionone and (\(E\))-2-octenal, all compounds in DM exhibited higher rOAV values than those in DY; this discrepancy might be the reason why DY lacks a pronounced aroma. \(\beta\)-Ionone is a 9,10/9\({}^{\prime}\),10\({}^{\prime}\) cleavage product of \(\beta\)-carotene, and can be extensively found in fruits, flowers, and vegetables [29]. \(\beta\)-Ionone has a low threshold; hence, the compound presents a strong woody and floral aroma at low levels. \(\beta\)-Ionone is receiving increasing \begin{table}
\begin{tabular}{c c c c} \hline
**NO** & **Compound Name** & **VIP** & \(p\) \\ \hline C17 & Octanal & 1.102 & 0.000 \\ C37 & Geranylacetone & 1.101 & 0.000 \\ C26 & Butyl acetate & 1.100 & 0.002 \\ C36 & Dihydro-\(\beta\)-ionone & 1.099 & 0.000 \\ C23 & 2,6-Dimethyl-4-heptanone & 1.097 & 0.000 \\ C14 & (E)-2-Hexenal & 1.097 & 0.000 \\ C10 & (6Z)-2,6-Dimethylocta-2,6-diene & 1.096 & 0.000 \\ C13 & Hexanal & 1.094 & 0.000 \\ C38 & \(\beta\)-Ionone & 1.094 & 0.000 \\ C35 & Thessipriare & 1.090 & 0.001 \\ C24 & 4,6-Dimethylheptan-2-one & 1.082 & 0.001 \\ C18 & Benzeneacetaldehyde & 1.081 & 0.002 \\ C25 & 4,7,9-Megastigmatien-3-one & 1.070 & 0.002 \\ C19 & (E)-2-Octanal & 1.068 & 0.003 \\ C40 & Farnesene & 1.060 & 0.008 \\ C11 & 1-Octanol & 1.059 & 0.005 \\ C32 & Phenethyl acetate & 1.059 & 0.005 \\ C5 & 4-Methyldodecane & 1.022 & 0.027 \\ C28 & Ethyl heptanoate & 1.019 & 0.012 \\ C42 & 2-Ethylfuran & 1.014 & 0.001 \\ C31 & Ethyl caprylate & 1.009 & 0.017 \\ C4 & Dodecane & 1.009 & 0.034 \\ C8 & 7,9-Dimethylhexadecane & 1.001 & 0.024 \\ \hline \end{tabular}
\end{table} 
Table 2: Key volatile compounds based on VIP \(>\) 1 and \(p\) \(<\) 0.05. Figure 5: rOAV radar map of volatile aroma compounds. levels of attention in the biomedicine field owing to its anti-inflammatory, antibacterial, and anticancer properties [30]. Phenethyl acetate is a high-value natural volatile ester with an intense floral aroma; it is the primary aromatic ester in roses, jasmine, and other plants, and has been widely added to cosmetics, food, and beverages to enhance aroma and flavor [31; 32]. As shown in Table 3, volatile aroma compounds that exhibit green odors, such as (_E_)-2-hexenal (green), 1-octanol (green, citrus), and hexanal (green, grass), showed stronger roAV in DM than in DY, which indicated that DM has a greener aroma. It is worth noting that compounds with pleasant aromas, such as benzeneacetaldehyde (sweet, honey), ethyl heptanoate (fruity, sweet), and ethyl caprylate (pineapple, fruity), were more abundant in DM than DY. Dihydro-\(\beta\)-ionone has a mellow, sweet, and fresh cedar aroma; it is an attractive compound for commercial flavor and fragrance applications, and is used in the cosmetics, perfumery, food, and beverage industries [33]. While dihydro-\(\beta\)-acetone was found to be the critical volatile aroma component in DM, it only modified the fragrance of DY. This difference is possibly one of the reasons for the different fragrances of the two samples, as was also observed for hexanal and benzeneacetaldehyde. To more intuitively analyze the differences in the aroma characteristics of DY and DM, the critical volatile aroma compounds were classified and summarized according to aroma type. Figure 6 shows that the aroma characteristics of DY and DM can be described as being woody (more prominent in DY) followed by floral and fruity. DM exhibited a more prominent floral aroma. Moreover, woody, green, cedar, fruity, and sweet aromas contributed to the more intense aroma of DM.