## 3 Results and Discussion
### Optimization of the Composition Ratio of RFIS thought RSM  
The central composite design was developed from the coded design in Table 1 (RSM 2). A total of 17 experiments were randomly performed, consisting of 8 fractional points, 6 star points, and 3 central points. The dependent variables were the measurements of baked potato-like and savory odors, which were the most dominant odors among the six odors identified by QDA. In the case of the baked potato-like odor, the sensory test results obtained from 13 QDA panelists using a 9-point scale showed a range from 3.78 to 6.22 throughout the entire experimental range. Among them, the highest value of 6.22 was observed in No. 16 (methionine 0.10 g (\(w/v\)), threonine 0.70 g (\(w/v\)), glycine 1.30 g (\(w/v\))) and the lowest value of 3.78 was obtained in No. 10 (methionine 0.06 g (\(w/v\)), threonine 0.90 g (\(w/v\)), glycine 0.55 g (\(w/v\))). On the other hand, in the case of savory odor, it showed a range from 1.89 to 4.40 throughout the entire experimental range. Among them, the highest value of 4.40 was observed in No. 1 (methionine 0.14 g (\(w/v\)), threonine 0.50 g (\(w/v\)), glycine 0.55 g (\(w/v\))) and No. 2 (methionine 0.14 g (\(w/v\)), threonine 0.90 g (\(w/v\)), glycine 1.05 g (\(w/v\))) and the lowest value of 1.89 was obtained in No. 9 (methionine 0.10 g (\(w/v\)), threonine 0.70 g (\(w/v\)), glycine 0.30 g (\(w/v\))). The results of the multiple regression analysis  
\begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Factors**} & \multicolumn{2}{c}{**Coefficients**} \\ \cline{2-3}  & **Brittleness (N)** & **Puffing Ratio (\%)** \\ \hline Constant & 7.5409 & \multirow{2}{*}{Linear} & 114.949 \\  & & & \\
[Laver and surimi ratio] & 0.3350 * & 0.100 \\
[Frying time] & \(-\)0.9833 * & 0.093 \\  & & Quadratic \\
[Laver and surimi ratio]2 & \(-\)0.0278 & 0.072 \\
[Frying time]2 & 0.1435 * & 0.091 \\  & & Cross product \\
[Laver and surimi ratio] \(\times\) & \(-\)0.0300 & \(-\)0.025 \\
[Frying time] & \(-\)0.0300 & \(-\)0.025 \\ \hline Model & & \\ Linear & 0.000 & 0.648 \\ Quadratic & 0.003 & 0.640 \\ Cross product & 0.685 & 0.922 \\ R-square & 0.9897 & 0.2728 \\ Total model & 0.000 & 0.833 \\ Lack of fit & 0.132 & 0.014 \\ \hline \hline \end{tabular}  
* \(p<0.05\).  
\end{table}
Table 3: Model coefficients estimated by multiple linear regression of dependent variables (brittleness and puffing ratio) for processing layer chip.  
of the dependent variables (baked potato-like and savory odors) obtained according to the central composite design are shown in Table 4. It was not significant in the case of savory odor either. The results of the response surface model equations for baked potato-like and savory odors (ANOVA) showed that the coefficient of determination (R\({}^{2}\)) and lack of fit values were 0.7989 and 0.648 for baked potato-like odor and 0.4614 and 0.818 for savory odor. This indicates that the model equation for baked potato-like odor is more appropriate (Table 4). Based on the RSM results, the optimum composition ratio that satisfies the maximum value of baked potato-like (Y\({}_{1}\)) and savory (Y\({}_{2}\)) odors was methionine (X\({}_{1}\)) 0.18 g, threonine (X\({}_{2}\)) 1.10 g, and glycine (X\({}_{3}\)) 0.80 g, respectively. Based on the optimum composition ratio, the predicted values of baked potato-like and savory odors were 6.5321 and 4.6537, respectively.  
In addition, sniffing test results showed that the reaction odor had baked potato-like, savory, and sweet odors confirming the effectiveness of the application of the reaction flavor. [PERSON] et al. [19] also reported that a model experiment in which methionine and glucose were reacted at 100 \({}^{\circ}\)C emitted boiled potato and sweet odors.