## 3 Results
### Yield of the Mushroom DFI  
The yield of mushroom DFI obtained varied between a minimum of 15% to a maximum of 53% of the mushroom dry weight (0.77% to 2.8% of the fresh mushroom weight for a mushroom water content of 94.7%) (Table 1). Based on the central composite design, each of the three factors (\(T\), \(C_{H_{2}O_{2}}\), and \(C_{NaOH}\)) had a significant effect on the mushroom DFI yield (Table 2). There was also observed a significant interaction between \(T\) and \(C_{NaOH}\). Using multiple regression analysis, a second-order polynomial equation model based on coded levels was used to fit the experimental results. This model which consists of the factors found to be significant is shown in Table 1. The ANOVA results of the model obtained indicated an adequate performance with R\({}^{2}=0.64\), implying that 64% of the variations observed for the mushroom DFI yield are explained by the factors considered. It was therefore considered that the model provided a good description of the experimental data. Nevertheless, the F-test for the lack of fit was also significant (\(p<0.05\)) therefore a more complicated model or additional factors (for example variability of the mushrooms used in each experiment) are required to a higher fit of the experimental data [41]. Figure 1 shows the three-dimension response surface curves of mushroom DFI yield for each pair of factors by keeping the third factor constant at the level where it presented the maximum value. The factor \(T\) presented the highest positive effect (Table 2, Figure 1a) on the mushroom DFI yield (maximum for the +1.682 level), followed by the factor \(C_{H_{2}O_{2}}\) were it was observed a positive effect (Table 2; Figure 1b) for the linear effect and a negative effect for the quadratic effect (maximum value for the \(C_{H_{2}O_{2}}>0\) level). The interaction between the factor \(T\) and \(C_{NaOH}\) and the linear effect of the factor \(C_{NaOH}\) both had a positive effect on the DFI yield (Table 2, Figure 1a).  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Coded**} & \multicolumn{3}{c}{**Actual**} & \multicolumn{3}{c}{**Protein 1**} & \multicolumn{3}{c}{**Fat (g/100 g)**} & \multicolumn{3}{c}{**Fate (g/100 g)**} & \multicolumn{3}{c}{**Fate (g/100 g)**} & \multicolumn{3}{c}{**Ash (g/100 g)**} \\ \hline \(\epsilon_{\text{NLO}}\) (**M0**) & \(\epsilon_{\text{H-O}}\) (**\%**) & **Time (h)** & \(\epsilon_{\text{NLO}}\) (**M0**) & \(\epsilon  
\begin{table}
\begin{tabular}{l l l c c c c c c c c c c c c} \hline \multicolumn{1}{c}{} & \multicolumn{4}{c}{**Factor**} & \multicolumn{1}{c}{**C\({}_{H_{0}O}\)**} & \multicolumn{1}{c}{**Lack of**} & \multicolumn{1}{c}{**Pure**} & \multicolumn{1}{c}{**Total SS**} \\ \hline  & & **Time (L)** & **Time (Q)** & **  
These results show that during the treatment of the mushroom material with the alkaline solution containing hydrogen peroxide there was observed an insolubilization of material with treatment time, this insolubilization being promoted by higher NaOH concentrations. According to the response surface analysis, the predicted maximum mushroom DFI yield in the range studied is 2.9% of the mushroom fresh weight (95% prediction interval: 2.1-3.6%) when the factor \(T\) is +1.682, the factor \(C_{H_{2}O_{2}}\) is +0 and the factor \(C_{NaOH}\) is +1.682, corresponding to 55% of the mushroom solids. To understand what is being insolubilized during the treatment of the mushroom material, and as the composition of DFIs are important from a legal perspective [47] but also for its nutritional and functional properties, the fiber, protein, lipid and ash contents of the DFI were determined.