# Effects of Glyoxylic Acid on Metabolism and Ripening of 'Rocha' Pears Treated with 1-MCP
## 3 Results
### Multivariate Analysis Corroborates GLA-Induced Physiological Changes
In order to assess the contribution of the treatment to the aroma of the fruit, the emissions of VOCs were analyzed, and those of greater importance are presented in Table 1.  
Concerning the effects of GLA treatment on VOC emissions, it was observed that there was a notable spike in specific volatile compounds, such as hexanal and (E)-2-hexanal, at 7 days, followed by a drop at 15 days when compared to the CTRL group. Moreover, GLA drove a substantial increase in hexyl and butyl acetate levels by the 15 th day of shelf-life, while CTRL showed only a minor rise. For limonene and ethanol, the CTRL maintained higher levels than the GLA group across time, although they were not statistically different. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multicolumn{2}{c}{**Aroma Volatile**} & **0 D** & **7 D** & **15 D** \\ \hline \multirow{2}{*}{Hexanal} & CTRL & 1 \(\pm\) 0.22 \({}^{\text{B}}\) & 12.94 \(\pm\) 3.50 \({}^{\text{Ab}}\) & 11.92 \(\pm\) 4.41 \({}^{\text{Aa}}\) \\ \cline{2-5}  & GLA & 1 \(\pm\) 0.22 \({}^{\text{C}}\) & 37.00 \(\pm\) 5.28 \({}^{\text{Aa}}\) & 15.38 \(\pm\) 2.98 \({}^{\text{Ba}}\) \\ \hline \multirow{2}{*}{Hexyl acetate} & CTRL & 1 \(\pm\) 0.45 \({}^{\text{A}}\) & 0.96 \(\pm\) 0.26 \({}^{\text{Aa}}\) & 2.36 \(\pm\) 0.91 \({}^{\text{Aa}}\) \\ \cline{2-5}  & GLA & 1 \(\pm\) 0.45 \({}^{\text{B}}\) & 0.92 \(\pm\) 0.24 \({}^{\text{Ba}}\) & 12.70 \(\pm\) 4.34 \({}^{\text{Ab}}\) \\ \hline \multirow{2}{*}{Butyl acetate} & CTRL & 1 \(\pm\) 0.28 \({}^{\text{B}}\) & 0.46 \(\pm\) 0.13 \({}^{\text{Bb}}\) & 5.04 \(\pm\) 1.86 \({}^{\text{Aa}}\) \\ \cline{2-5}  & GLA & 1 \(\pm\) 0.28 \({}^{\text{B}}\) & 0.77 \(\pm\) 0.08 \({}^{\text{Ba}}\) & 7.66 \(\pm\) 0.96 \({}^{\text{Aa}}\) \\ \hline \multirow{2}{*}{(E)-2-Hexanal} & CTRL & 1 \(\pm\) 0.19 \({}^{\text{B}}\) & 8.24 \(\pm\) 1.79 \({}^{\text{Ab}}\) & 12.46 \(\pm\) 2.45 \({}^{\text{Aa}}\) \\ \cline{2-5}  & GLA & 1 \(\pm\) 0.19 \({}^{\text{C}}\) & 34.11 \(\pm\) 5.48 \({}^{\text{Aa}}\) & 9.43 \(\pm\) 0.16 \({}^{\text{Ba}}\) \\ \hline \multirow{2}{*}{Limonene} & CTRL & 1 \(\pm\) 0.02 \({}^{\text{B}}\) & 2.08 \(\pm\) 0.05 \({}^{\text{Aa}}\) & 1.02 \(\pm\) 0.02 \({}^{\text{Ba}}\) \\ \cline{2-5}  & GLA & 1 \(\pm\) 0.02 \({}^{\text{A}}\) & 0.96 \(\pm\) 0.15 \({}^{\text{Ab}}\) & 0.93 \(\pm\) 0.03 \({}^{\text{Aa}}\) \\ \hline \multirow{2}{*}{2-Ethyl-hexanol} & CTRL & 1 \(\pm\) 0.02 \({}^{\text{B}}\) & 0.85 \(\pm\) 0.04 \({}^{\text{Aa}}\) & 0.48 \(\pm\) 0.13 \({}^{\text{Aa}}\) \\ \cline{2-5}  & GLA & 1 \(\pm\) 0.02 \({}^{\text{A}}\) & 0.37 \(\pm\) 0.07 \({}^{\text{Bb}}\) & 0.52 \(\pm\) 0.17 \({}^{\text{Ba}}\) \\ \hline \multirow{2}{*}{Ethanol} & CTRL & 1 \(\pm\) 0.06 \({}^{\text{B}}\) & 1.49 \(\pm\) 0.36 \({}^{\text{Ba}}\) & 3.02 \(\pm\) 0.33 \({}^{\text{Aa}}\) \\ \cline{2-5}  & GLA & 1 \(\pm\) 0.06 \({}^{\text{B}}\) & 2.18 \(\pm\) 0.9 \({}^{\text{ABa}}\) & 2.92 \(\pm\) 0.60 \({}^{\text{Aa}}\) \\ \hline \end{tabular} Different capital letters indicate significant differences (\(p<\) 0.05) across time for each condition. Different small letters indicate significant differences (\(p<\) 0.05) between conditions at each timepoint (0, 7, and 15 days).  
\end{table} 
Table 1: Major VOC emissions in ‘Rocha’ years after treatment during shelf-life at 20 \({}^{\circ}\)C. Values are means \(\pm\) standard deviations of normalized data. Figure 6: ACC content and ACO activity variation in ‘Rocha’ years after treatment with GLA during shelf-life at 20 \({}^{\circ}\)C. Values are means \(\pm\) standard deviations of normalized data. Different capital letters indicate significant differences (\(p<\) 0.05) across time for each condition. Different small letters indicate significant differences (\(p<\) 0.05) between conditions at each timepoint (0, 7, and 15 days).