## 3 Results and Discussion
### Analysis of ROAV Values of VOCs during the Ripening Process of R. roxburghii  
The aroma characteristics of 145 volatiles detected by HS-SPME-GC-MS at five ripening stages of _R. roxburghii_ fruit were not determined solely by their relative content, but rather by the relative odor activity value (ROAV), which combines both the content and odor threshold.The ROAV is a widely used method for evaluating the contribution of volatile substances to the overall aroma. According to [PERSON] et al. [57], substances with an ROAV of \(>\)1 are perceived by humans and contribute to the overall aroma. In total, 53 VOCs with an ROAV of \(>\)1 were identified (Table 2). These substances were categorized into 17 aroma categories, including flower, fruit, grass, green, fat, soap, wood, caramel, balsamic, sweet, mint, mushroom, citrus, metal, pungent, lemon, and sweat aromas. This finding highlights the diversity and complexity of the aroma profiles of _R. roxburghii_ fruit during ripening. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multicolumn{2}{c}{**Odor**} & \multirow{2}{*}{**Class**} & \multirow{2}{*}{**Compounds**} & \multicolumn{2}{c}{**Odor**} & \multicolumn{4}{c}{**ROAV**} \\ \cline{4-9} \multicolumn{2}{c}{**Descriptions**} & & & **Threshold** & **(mg/kg)** & **I** & **II** & **III** & **IV** & **V** \\ \hline \multirow{9}{*}{Green} & Aldehydes & 2- (E)-Hexenal & 0.0887 & 625.22 & 238.06 & 219.73 & 2363.27 & 207.05 \\  & & (E) 2-Octonal & 0.003 & 1862.51 & ND & 1572.29 & 310.21 & ND \\  & & 1-Heptanol & 0.0054 & ND & ND & ND & ND & 390.45 \\  & & (Z)-2-Hexen-1-ol & 0.3593 & ND & ND & ND & ND & 2.33 \\  & & (Z)-3-Hexenyl acetate & 0.013 & 3544.18 & 16,836.82 & 10,973.98 & 2272.36 & ND \\  & & (Z)-3-Hexenyl butanoate & 0.5 & ND & ND & 31.07 & 2.52 & ND \\  & Ketones & Geranylacetone & 0.06 & 19.92 & 21.61 & 54.07 & ND & 68.93 \\  & Aldehydes & (E)-2-Pentenal & 0.98 & 4.43 & 2.24 & 2.86 & 4.11 & 8.49 \\  & & Isoamyl acetate & 0.00015 & ND & ND & 3077.42 & 4794.89 & 33,556.71 \\  & & & Hexyl acetate & 0.115 & 29.99 & 243.78 & 119.23 & 24.50 & 27.90 \\  & & Ethyl acrylate & 0.0193 & ND & 20.01 & 21.35 & 1636.14 & 223.99 \\ Fruit & Esters & Hexyl butyrate & 0.203 & ND & 2.49 & 6.06 & ND & ND \\  & & 2-Methylbutyl acetate & 0.005 & ND & ND & ND & 132.12 & 336.56 \\  & & Ethyl Hexanoate & 0.0022 & ND & ND & ND & 14,562.77 & 6978.21 \\  & & Methyl hexanoate & 0.07 & ND & ND & ND & ND & 125.28 \\  & Ketones & Nootkartone & 0.28 & ND & ND & ND & 4.73 & ND \\  & Esters & Caprylic acid methyl & 0.2 & ND & ND & 2.32 & 2.98 & 177.04 \\ Citrus & & & (Z)-\(\beta\)-Ocimene & 0.034 & ND & 85.38 & 326.18 & 1581.58 & ND \\  & Alkenes & & 4-Isopropyltoluene & 0.085 & ND & ND & ND & 7.00 \\  & Aldehydes & Hexanal & 0.005 & 16,225.60 & 8652.63 & 9827.86 & 35,421.65 & 13,307.02 \\  & Alcohols & (3E)-3-Hexen-1-ol & 0.11 & ND & ND & 461.03 & ND & 930.99 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: ROAV values of VOCs in _R. roxburghii_ fruit at different ripening stages. As illustrated in Figure 3A, the odors associated with fruit, green, grass, flower, and so on underwent significant changes during the ripening of _R. roxburghii_. At stage I, a total of 12 aroma types were identified, predominantly characterized by floral and fruity notes, with a unique mint flavor (\(\beta\)-cyclodextrin contribution, ROAV > 100) that was exclusively observed at stages I and IV. At stage II, the number of aroma categories decreased to 10, with the introduction of citrus and mushroom flavors, which were derived from (Z)-\(\beta\)-ocimene and 6-methyl-5-hepten-2-one, respectively. Stage III saw an increase to 15 aroma categories, incorporating pungent and sweat flavors from ethyl vinyl ketone and octanoic acid, respectively; notably, pungent flavors were present only at stages III and V. Stage IV closely resembled stage III but lacked the pungent notes, while the concentration of mint increased.