## 3 Results and Discussion
### Optimization of the Microwave Vacuum Drying Technology  
#### 3.3.1 Test Design Scheme and Results  
To investigate the influencing laws of the drying control parameters on the drying features of mulberry and to obtain the optimal parameter combination--in addition to determining the influence laws of the drying control parameters on the drying features of  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Element**} & \multirow{2}{*}{**Level**} & \multirow{2}{*}{**Soluble**} & \multirow{2}{*}{**Chewiness**} & \multirow{2}{*}{**Vc**} & \multirow{2}{*}{**Synthesis**} & \multirow{2}{*}{**Comparison**} \\  & & & & & & **Ranking** \\ \hline \multirow{8}{*}{Microwave drying temperature/\({}^{\circ}\)C} & 40.0 & 0.000 & 1.000 & 0.404 & 0.299 & 11 \\  & 42.0 & 0.207 & 0.837 & 0.514 & 0.405 & 9 \\  & 44.0 & 0.366 & 0.785 & 0.656 & 0.512 & 7 \\  & 46.0 & 0.520 & 0.687 & 0.671 & 0.584 & 5 \\  & 48.0 & 0.664 & 0.566 & 0.769 & 0.660 & 4 \\  & 50.0 & 0.784 & 0.550 & 0.774 & 0.729 & 2 \\  & 52.0 & 1.000 & 0.329 & 0.801 & 0.812 & 1 \\  & 54.0 & 0.798 & 0.381 & 0.826 & 0.707 & 3 \\  & 56.0 & 0.572 & 0.285 & 0.802 & 0.546 & 6 \\  & 58.0 & 0.424 & 0.171 & 0.847 & 0.440 & 8 \\  & 60.0 & 0.269 & 0.019 & 0.905 & 0.323 & 10 \\ \hline \multirow{8}{*}{Vacuum degree/MPa} & 0.01 & 0.220 & 0.129 & 1.000 & 0.335 & 9 \\  & 0.02 & 0.320 & 0.325 & 0.930 & 0.427 & 8 \\ \cline{1-1}  & 0.03 & 0.353 & 0.474 & 0.897 & 0.475 & 7 \\ \cline{1-1}  & 0.04 & 0.439 & 0.494 & 0.838 & 0.521 & 6 \\ \cline{1-1}  & 0.05 & 0.492 & 0.650 & 0.828 & 0.587 & 4 \\ \cline{1-1}  & 0.06 & 0.655 & 0.669 & 0.708 & 0.667 & 3 \\ \cline{1-1}  & 0.07 & 0.861 & 0.709 & 0.696 & 0.798 & 1 \\ \cline{1-1}  & 0.08 & 0.844 & 0.485 & 0.406 & 0.686 & 2 \\ \cline{1-1}  & 0.09 & 0.908 & 0.187 & 0.000 & 0.585 & 5 \\ \hline \multirow{8}{*}{Microwave power/W} & 200 & 0.135 & 0.000 & 0.177 & 0.111 & 7 \\ \cline{1-1}  & 250 & 0.226 & 0.254 & 0.357 & 0.255 & 6 \\ \cline{1-1}  & 300 & 0.476 & 0.282 & 0.432 & 0.424 & 5 \\ \cline{1-1}  & 350 & 0.828 & 0.359 & 0.600 & 0.681 & 1 \\ \cline{1-1}  & 400 & 0.651 & 0.541 & 0.631 & 0.622 & 3 \\ \cline{1-1}  & 450 & 0.488 & 0.774 & 0.563 & 0.567 & 4 \\ \cline{1-1}  & 500 & 0.586 & 0.751 & 0.675 & 0.639 & 2 \\ \hline \hline \end{tabular}
\end{table}
Table 10: Membership functional values of the test factors and comprehensive evaluation results.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Index**} & **Principal** & **Principal** & **Principal** & **Composite Score** & \\  & **Component 1** & **Component 2** & **Component 3** & **Coefficient** & **Weight/\%** \\ \hline Value of chromatism & \(-0.098\) & \(-0.703\) & \(0.632\) & \(-0.110\) & 9 \\ Soluble solid & \(0.515\) & \(0.366\) & \(-0.130\) & \(0.369\) & 31 \\ Chewiness & \(0.128\) & \(0.929\) & \(-0.045\) & \(0.281\) & 23 \\ Hardness & \(-0.082\) & \(-0.108\) & \(1.085\) & \(0.115\) & 10 \\ Vc & \(0.574\) & \(0.052\) & \(-0.142\) & \(0.329\) & 27 \\ \hline \hline \end{tabular}
\end{table}
Table 9: The linear combination coefficient and weight results.  
mulberry and to obtain the optimal parameter combination--mulberries with a longitudinal diameter of 33 \(\pm\) 0.5 mm and a horizontal diameter of 16.5 \(\pm\) 0.5 mm were chosen as research objects, and these were determined according to the single-factor experimental results. The material surface temperature (X\({}_{1}\)), vacuum degree (X\({}_{2}\)), and microwave power (X\({}_{3}\)) were chosen as independent variables, while the sweetness (Y\({}_{1}\)), chewiness (Y\({}_{2}\)), and VC content (Y\({}_{3}\)) were chosen as dependent variables. The ternary quadratic regression orthogonal rotary optimization test was carried out using the star point design--response surface method. The factor level codes are listed in Table 11, and the experimental design and results are shown in Table 12.