## 3 Results
### Effect of Steaming On Vitamin Retention in Potato Tubers  
For the calculation of vitamin retention in steaming treatment, the vitamin contents of each potato cultivar were calculated on a dry-weight (DW) basis and the change percentages were compared (Table 5). Water content did not change significantly after steaming (78.3-82.9%). Prior to steaming, the three cultivars with the highest vitB9 levels were 'YouJin', 'V7', and 'TianShu 11' (Table 3). After steaming, vitB9 levels decreased over \(-\)50% in most cultivars. Whereas those in 'TianShu 11' and 'TianShu 12' did not change much after steaming (Table 5; Figure 3a). Notably, the vitB9 content in steamed tubers of 'XinDaPing' increased significantly to 17.83 \(\pm\) 3.53 \(\pm\) -100 g FW, which was over 2-fold of that of YouJin (8.74 \(\pm\) 1.17 \(\mathrm{\SIUnitSymbolMicro}\)/100 g FW; \(p\) < 0.01; Table 6; Figure 3a). Before steaming, 'TianShu 11', 'XinDaPing', 'QingShu 9', and 'XiSen 6' contained more vitC than the other cultivars (Table 3). The vitC levels of all cultivars except 'YouJin' decreased over \(-\)26.4% after steaming, with the greatest decrease (\(-\)73.8%) observed in 'XiSen 6' (Table 5; Figure 3b). Compared with 'XiSen 6', the decrease in 'TianShu 11' (\(-\)31.5%) and 'XinDaPing' (\(-\)26.4%) were significantly less, resulting as 76.03 \(\pm\) 0.85 mg/100 g FW and 85.24 \(\pm\) 6.36 mg/100 g FW in steamed tubers, respectively (both \(p\) < 0.01; Figure 3b; Table 6). The top three cultivars for vitE were 'YouJin', 'QingShu 9', and 'XiSen 6' before steaming (Table 4). In most cultivars, vitE levels decreased after steaming (Table 5; Figure 3c). However, those of 'L8' (155.5%), 'TianShu 11' (277.7%), and 'XinDaPing' (286.5%) significantly increased compared with that of 'YouJin' (\(-\)57.5%), resulting as 33.42 \(\pm\) 7.21 mg/kg FW, 48.03 \(\pm\) 6.51 mg/kg FW, and 61.71 \(\pm\) 9.11 mg/kg FW in steamed tubers, respectively (all \(p\) < 0.01; Tables 5 and 6; Figure 3c). After steaming, vitB9, vitC, and vitE levels were consistently higher in 'TianShu 11' and 'XinDaPing' than in all other cultivars (Table 6), which suggests that they are better sources among the detected ones of multiple vitamins in steamed potatoes.  
Figure 2: Correlation among the derivatives of vitB9 and vitE, respectively, in tubers of potato cultivars before steaming. (**a**) Correlation results among derivatives of vitB9; (**b**) Correlation results among derivatives of vitE. *, \(p\) < 0.01; **, \(p\) < 0.001; ***, \(p\) < 0.0001.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Cultivar Name** & \begin{tabular}{c} **Total Vitamin** \\ **B9 in Raw** \\ **Tubes** \\ **(g100\(\&\)BW)** \\ \end{tabular} & \begin{tabular}{c} **Total Vitamin C in** \\ **Raw Tubes** \\ **(g100\(\&\)BW)** \\ \end{tabular} & \begin{tabular}{c} **Vitamin C in** \\ **Raw Tubes** \\ **(mg100\(\&\)BW)** \\ \end{tabular} & \begin{tabular}{c} **Vitamin C in** \\ **Tubes** \\ **(mg100\(\&\)BW)** \\ \end{tabular} & \begin{tabular}{c} **Total Vitamin E** \\ **(v3)** \\ **(mg100\(\&\)BW)** \\ \end{tabular} & \begin{tabular}{c} **Total Vitamin E** \\ **(mg100\(\&\)BW)** \\ \end{tabular} & \begin{tabular}{c} **Vitamin E CP** \\ **(mg100\(\&\)BW)** \\ \end{tabular} \\ \hline \hline \
\begin{tabular}{c} \({}^{\prime}\)YouJni\({}^{\prime}\) \\ \(\gamma\)\(\gamma\) \\ \(\gamma\)\(\gamma\) \\ \(\gamma\)\(\gamma\) \\ \(\gamma\)\(\gamma\) \\ \end{tabular} &
\begin{tabular}{c} 96.66 \(\pm\) 5.44 \\ 13.68 \(\pm\) 0.62 \\ 33.94 \(\pm\) 0.69 \\ 34.69 \(\pm\) 0.67 \\ 33.93 \(\pm\) 0.54 \\ 4.69 \(\pm\) 0.67 \\ 4.69 \(\pm\) 0.  
Figure 3: Change percentages of vitB9, vitC, and vitE in tubers of potato cultivars after steaming, respectively. (**a**) Change percentage of vitB9; (**b**) change percentage of vitC; (**c**) change percentage of vitE.