## 3 Results
### Experimental Results and Analysis of Variance  
The experiment investigated the effects and interactions of various factors on the response. Table 2 presents the factor levels for each specific experimental group along with their corresponding response results. In Table 3, polynomial quadratic regression models for each response were obtained after excluding non-significant factors, and corresponding \(r^{2}\) and CV values were calculated as standards to assess model accuracy. Here, \(r^{2}\) represents the correlation coefficient, while CV denotes the coefficient of variation expressed as a percentage of standard deviation to mean ratio. A smaller value indicates higher reliability of data; typically, a CV value is expected to be less than 12%. The results of the analysis of variance are shown in Table 4, indicating that the model should exhibit significance (\(p<0.05\)), while pseudo-loss should not demonstrate significance (\(p>0.05\)) [22; 34]. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Factors**} & \multirow{2}{*}{**Symbols**} & \multicolumn{6}{c}{**Coded Versus Uncoded Values**} \\ \cline{3-8}  & & \(\alpha\) = 2.378 & \(-\)1 & 0 & 1 & \(\alpha\) = 2.378 \\ \hline Drying temperature (\({}^{\circ}\)C) & T & 35 & 40.8 & 45 & 49.2 & 55 \\ Relative humidity (\%) & RH & 30 & 35.8 & 40 & 44.2 & 50 \\ Initial moisture content (\%) & MC & 20 & 22.3 & 24 & 25.7 & 28 \\ Wind speed (m/s) & V & 0.36 & 0.5 & 0.6 & 0.7 & 0.84 \\ Tempering ratio & TR & 1 & 1.9 & 2.5 & 3.1 & 4 \\ \hline \hline \end{tabular} Note: hot-air temperature, T; hot-air relative humidity, RH; initial moisture content, MC; hot-air wind speed, V; tempering ratio, TR.  
\end{table} 
Table 1: Factor levels of response surface test. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Std**} & \multirow{2}{*}{**T (\({}^{\circ}\)C)**} & \multirow{2}{*}{**RH (\%)**} & \multirow{2}{*}{**MC (\%)**} & \multirow{2}{*}{**V (m/s)**} & \multirow{2}{*}{**TR**} & \multicolumn{2}{c}{**Dtt**} & \multicolumn{2}{c}{**AT**} & \multirow{2}{*}{**PC (\%)**} & \multirow{2}{*}{**FC (\%)**} & \multicolumn{2}{c}{**AC**} & \multicolumn{2}{c}{**APC**} \\  & & & & & & & & (**min**) & (\({}^{\circ}\)C-h) & & & (**g/100 g**) & **(g/100 g**)** \\ \hline  
\hline \hline \end{tabular}
\end{table} 
Table 2: Protocol and results of response surface experiment. Quadratic and cubic regression models were developed for various factors including drying temperature, relative humidity, tempering ratio, initial moisture content, total drying time, effective cumulative temperature, protein content, fat content, amylose levels and amylopsin activity. A comparison of the coefficient of determination (R\({}^{2}\)) between the quadratic and cubic regression models revealed that, while the R\({}^{2}\) value improved with the inclusion of cubic terms, this enhancement was accompanied by a significant increase in model complexity and computational demands. Consequently, a quadratic mathematical model--excluding non-significant variables--was employed to assess the experimental results. The interaction between input variables and responses was further examined through analysis of variance (ANOVA). During this analytical process, non-significant