# Aroma Compound Release from Starches of Different Origins: A Physicochemical Study
## 4 Results
### Mass Transfer Coefficients for Evaporation of Aroma Compounds from Starches of Different Origins  
As described above, when the glass vessel containedarches of different botanical origins impregnated with an aromatic compound and connected to the free end of the diffusion column, the mass transfer coefficients needed for the evaporation of the aroma compounds from the starch granules to the carrier gas could be calculated.  
By applying Equation (6) as above, the values of \(k_{c}\) were calculated. In addition, from the plot of \(\mathrm{ln}k_{c}\) versus 1/T, the activation energy \(E_{a}\) required for the evaporation of aroma compounds from starch was determined. The experimental temperatures used were 303.15 K, 313.15 K, 323.15 K, and 323.15 K. All experiments were performed in triplicate in order to calculate the average values of the mass transfer coefficients with their standard deviation.  
The results of the mass transfer coefficients, \(k_{c}\), as well as the activation energies needed for the evaporation of aroma compounds from starch are illustrated in Table 4.  
\begin{table}
\begin{tabular}{c c c c c} \hline \multirow{2}{*}{**T/K**} & \multirow{2}{*}{
\begin{tabular}{c} **Starch** \\ **Origin** \\ \end{tabular} } & \multicolumn{2}{c}{**Diacetyl**} & \multicolumn{2}{c}{**DI-Limonene**} \\ \cline{3-5}  & & **10\({}^{3}\)\(k_{c}\)/cm s\({}^{-1}\)** & **E\({}_{a}\)/kJ mol\({}^{-1}\)** & **10\({}^{3}\)\(k_{c}\)/cm s\({}^{-1}\)** & **E\({}_{a}\)/kJ mol\({}^{-1}\)** \\ \hline
303.15 & & 12.34 \(\pm\) 1.26 & & 7.40 \(\pm\) 0.54 & \\
313.15 & & 16.86 \(\pm\) 1.65 \({}^{a}\) & 19.14 \(\pm\) 1.88 & 14.62 \(\pm\) 1.21 \({}^{a}\) & \\
323.15 & & 19.26 \(\pm\) 0.86 \({}^{b}\) & 23.45 \(\pm\) 2.05 \({}^{b}\) & 49.66 \(\pm\) 2.44 \\
333.15 & & 25.19 \(\pm\) 2.32 & & 45.40 \(\pm\) 2.48 & \\ \hline
303.15 & & 0.49 \(\pm\) 0.02 & & 15.95 \(\pm\) 1.13 & \\
313.15 & & 2.24 \(\pm\) 0.09 & & 17.77 \(\pm\) 1.28 & \\
323.15 & & 7.16 \(\pm\) 0.15 & & 19.85 \(\pm\) 1.12 & \\
333.15 & & 16.46 \(\pm\) 0.78 & & 22.00 \(\pm\) 1.23 & \\ \hline
303.15 & & 9.04 \(\pm\) 0.86 \({}^{c}\) & & 7.76 \(\pm\) 0.23 \({}^{c}\) & \\
313.15 & & 11.24 \(\pm\) 0.93 & & 10.03 \(\pm\) 0.68 & \\
323.15 & & 14.81 \(\pm\) 1.53 \({}^{e}\) & & 11.84 \(\pm\) 0.42 \({}^{e}\) & \\
333.15 & & 18.27 \(\pm\) 1.23 & & 14.03 \(\pm\) 0.53 & \\ \hline
303.15 & & 10.84 \(\pm\) 0.85 & & 7.85 \(\pm\) 0.15 & \\
313.15 & & 17.09 \(\pm\) 1.02 & & 13.27 \(\pm\) 0.18 & \\
323.15 & & 22.46 \(\pm\) 1.23 \({}^{f}\) & 26.06 \(\pm\) 2.82 & 25.25 \(\pm\) 0.56 \({}^{f}\) & \\
333.15 & & 27.72 \(\pm\) 1.56 & & 36.40 \(\pm\) 1.23 & \\ \hline \end{tabular} The same letter indicates non-statistically significant values.  
\end{table}
Table 4: The mean values of the mass transfer coefficients, \(k_{c}\), and the activation energy, \(E_{a}\), needed for the evaporation of diacetyl and dl-limonene from starch granules of different origins to the gaseous phase at various temperatures, along with their standard deviation.  
\begin{table}
\begin{tabular}{c c c c c} \hline \multirow{2}{*}{**T/K**} & \multicolumn{2}{c}{**Diacetyl**} & \multicolumn{2}{c}{**DI-Limonene**} \\ \cline{2-5}  & **10\({}^{3}\)\(k_{c}\)/cm s\({}^{-1}\)** & **E\({}_{a}\)/kJ mol\({}^{-1}\)** & **10\({}^{3}\)\(k_{c}\)/cm s\({}^{-1}\)** & **E\({}_{a}\)/kJ mol\({}^{-1}\)** \\ \hline
303.15 & 12.64 \(\pm\) 0.34 & & 10.99 \(\pm\) 0.56 & \\
313.15 & 14.79 \(\pm\) 0.45 & & 11.88 \(\pm\) 0.89 & \\
323.15 & 18.18 \(\pm\) 0.93 & & 12.56 \(\pm\) 0.23 & \\
333.15 & 21.55 \(\pm\) 0.73 & & 13.31 \(\pm\) 0.38 & \\ \hline \end{tabular}
\end{table}
Table 3: The mean values of the mass transfer coefficients, \(k_{c}\), required for the evaporation of diacetyl and dl-limonene from the bulk liquid to the gaseous phase at various temperatures, along with the standard deviation and the corresponding activation energy, \(E_{a}\), needed for the procedure of evaporation.