# New Insight on the Formation of 2-Aminoacetophenone in White Wines
## 3 Results
### Influence of Antioxidants  
Another white blend (wine B) was spiked before artificial ageing with 3-IAA and different type of antioxidants including pure compounds (glutathione and gallic acid) and some oenological products (commercial tannins and inactivated yeast derivates). Concentrations of 2-AAP were measured in treated wines after artificial ageing. Figure 3 shows that all tested antioxidants significantly decreased the formation of 2-AAP. However, the efficiency levels differed between treatments. The smallest decreases were observed with the addition of GSH and inactivated yeast derivates (IYD), whereas gallic acid and both types of commercial tannins were the most efficient at reducing the \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Variety**} & **Chardonnay** & **Riesling** & **Muscat** & **Zelen** & **Welschriesling** \\  & **(_n = 8_)** & **(_n = 10_)** & **(_n = 12_)** & **(_n = 9_)** & **(_n = 6_)** \\ \hline Tryptophan & 1300 \(\pm\) 700 a & 700 \(\pm\) 700 b & 800 \(\pm\) 700 b & 900 \(\pm\) 700 b \\ \hline Anthranilic acid & 7.3 \(\pm\) 2.5 ab & 11.9 \(\pm\) 6.4 a & 5.7 \(\pm\) 2.9 b & 5.2 \(\pm\) 3.0 b & 5.3 \(\pm\) 3.1 b \\ \hline ILA & 149 \(\pm\) 59 b & 196 \(\pm\) 97 a & 134 \(\pm\) 109 b & 122 \(\pm\) 79 b & 84 \(\pm\) 23 c \\ \hline
3-IAA & 2.2 \(\pm\) 1.1 b & 4.5 \(\pm\) 3.6 b & 4.8 \(\pm\) 5.0 b & 18.8 \(\pm\) 18.3 a & 3.3 \(\pm\) 2.6 b \\ \hline Kynureine & 1.9 \(\pm\) 1.1 a & 1.0 \(\pm\) 0.7 b & 1.1 \(\pm\) 0.6 b & 1.2 \(\pm\) 0.6 b & 2.3 \(\pm\) 1.8 a \\ \hline
2-AAP & 1.2 \(\pm\) 2.1 c & 4.2 \(\pm\) 2.4 b & 8.7 \(\pm\) 5.5 a & 0.3 \(\pm\) 0.3 c & 0.3 \(\pm\) 0.3 c \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Concentration of 2-AAP precursors and 2-AAP (\(\upmu\)g/L) determined in five Slovenian and Croatian varietal white wines (\(n=45\)). One-way ANOVA was used to compare data. For each line, different letters represent significantly (\(p\leq\) 0.05) different concentrations between varieties. formation of 2-AAP. The addition of IYD in combination with commercial ellagitannins did not modify 2-AAP concentration in comparison to the addition of tannins alone (Figure 3). A second experiment consisted of testing the effects in wine A on the formation of 2-AAP from additions of two different concentrations of the antioxidants GSH, IYD and a commercial ellagitannin alone and in combination with IYD. Each antioxidant treatment was tested alone and with the addition of a mix of metal ions (Cu, Fe and Mn). The effect of antioxidants on the formation of 2-AAP was less significant in comparison to the first experiment. In this second wine, the addition of GSH and IYD did not modify the final concentration of 2-AAP (Figure 4). Only the addition of commercial ellagitannin (TA1) significantly reduced the 2-AAP concentration after artificial ageing. This decrease was more important with a higher dosage of tannins. Once again, the addition of IYD  
Figure 3: 2-AAP concentration measured in wine treated with different antioxidants (GSH—glutathione; YTD—inactivated yeast derivates, GA—gallic acid, TA1 and TA 2—different commercial tannins). Different letters above bars indicate significance at \(p\leq 0.05\) (Fischer’s LSD). All quoted uncertainty is the standard deviation of three replicates per treatment. Figure 2: 2-AAP concentration measured in wine A before artificial ageing (T0) and after artificial ageing without addition (C) and with addition of 3-indoleacetic acid (3-IAA) and indole-3-lactic acid (ILA), both at concentration 100 ug/L. Different letters above bars indicate significance at \(p\leq 0.05\) (Fischer’s LSD). All quoted uncertainty is the standard deviation of three replicates per treatment. did not modify the effect of tannin on the final level of 2-AAP, irrespective of tannin concentrations (Figure 4). When the metal ion mixture was added, the wines with GSH, IYD and tannin addition showed significantly lower levels of 2-AAP compared to the control wine (Figure 4).