# Experimental Verification of Yam (_Dioscorea rotundata_) Drying with Solar Adsorption Drying
## 3 Results
### Vitamin C and Color of Dried Yam  
Vitamin C content, expressed in mg/g dry matter, of the fresh and dried samples is presented in Table 3. All drying methods significantly affected the vitamin C content with the highest effect by OSD due to the direct exposure of the food to the sun. Similar to the previous experiment vitamin C loss for SAD is a bit higher than that for SD due to the additional drying of samples at night. Moreover, the vitamin C content of 'Dente' is about half to that of the previous experiment as a result of more drying days. Thus, extra drying days, further degrades vitamin C. It is also clear that the loss in vitamin C after drying varies for the different cultivars. The loss in vitamin C content after drying is in \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Method/Cultivar** & **Moisture** & **Ash** & **Crude Protein** & **Crude Fiber** & **Crude Fat** & **Carbohydrate** \\ \hline \multicolumn{8}{c}{ ‘Pona’} \\ \hline Fresh & 1.549 a & 0.020 b & 0.053 a & 0.010 b & 0.003 c & 0.915 a \\ SAD & 0.055 c & 0.038 a & 0.040 c & 0.011 a & 0.007 a & 0.906 b \\ SD & 0.054 c & 0.037 a & 0.041 c & 0.011 a & 0.007 a & 0.897 b \\ OSD & 0.075 b & 0.038 a & 0.046 b & 0.011 a & 0.006 b & 0.895 b \\ \hline \multicolumn{8}{c}{ ‘Liii’} \\ \hline Fresh & 1.872 a & 0.027 b & 0.042 a & 0.013 b & 0.002 b & 0.863 a \\ SAD & 0.061 b & 0.036 a & 0.034 b & 0.027 a & 0.006 a & 0.882 a \\ SD & 0.062 b & 0.038 a & 0.036 b & 0.027 a & 0.006 a & 0.885 a \\ OSD & 0.073 c & 0.039 a & 0.041 a & 0.027 a & 0.006 a & 0.891 a \\ \hline \multicolumn{8}{c}{ ‘Dente’} \\ \hline Fresh & 2.063 a & 0.020 b & 0.043 a & 0.011 b & 0.002 b & 0.856 b \\ SAD & 0.054 c & 0.030 a & 0.042 b & 0.022 a & 0.006 a & 0.901 b \\ SD & 0.055 c & 0.032 a & 0.042 b & 0.022 a & 0.005 a & 0.906 b \\ OSD & 0.078 b & 0.032 a & 0.041 b & 0.023 a & 0.006 a & 0.926 a \\ \hline \end{tabular}
\end{table} 
Table 2: Composition (kg/kg dry matter) of the three cultivars (fresh and dried) at different drying methods. line with what has been reported by [PERSON] et al. [14] who mentioned that drying methods greatly affect micronutrients, as corroborated by [PERSON] et al. [31]. [PERSON] and [PERSON] [32] reported improved quality and a more economical process as a result of reduced time of drying of the apricot by using a solar adsorbent integrated system. The measured L* values for fresh yam ranged between 81.83 and 83.68. The L* values (whiteness) for the dried samples decreased and ranged between 52.14 and 78.41 (see Table 4). The change in color is attributed to enzymatic browning [14] as a result of differences in phenolic compounds, which are associated with oxidative browning of yam. SD and SAD dried samples are close in the L* value, but despite the night drying periods the average values of the SAD dried samples show a lower change of whiteness than those for the SD dried samples. This makes the SAD system superior in terms of maintaining the white color of dried samples. The a* values show a slight change due to drying, while the b* values move toward less yellowness. The values with the same superscripts in the same column for each cultivar are not significantly different at \(p<0.05\).