## 4 Conclusions  
In this research, microwave drying was utilized to dry carrot slices of different thicknesses. The RSM was employed to explore the effects of the _MP_ (100, 200, and 300 W) and the _ST_ (2, 4, and 6 mm) on \(D_{t}\), _D\({}_{\it eff}\), SEC_, E\({}_{\rm ef}\), _GHG_ (CO\({}_{2}\) and NOx), and qualitative characteristics (color and shrinkage) of carrot slices considering the ultrasonication and blanching pretreatments. The results showed a reduction in the \(D_{t}\) (linearly), _SEC_ (linearly or quadratically), and _GHG_ (linearly and quadratically) by increasing the _MP_ and decreasing the _ST_, while causing an ascending trend in the E\({}_{\rm ef}\) (linearly or quadratically) and the \(D_{\it eff}\) (linearly). A statistical and graphical analysis indicated a significant effect of drying parameters (_MP_ and _ST_) on the response parameters of drying carrot slices in all pretreatments (_p_ < 0.0001). The optimization results showed that the _MP_ of 300 W and the _ST_ of 2 mm are the best independent variables for drying carrot slices. Different pretreatments reduced the _GHG_ \begin{table}
\begin{tabular}{l l l l l l l} \hline \hline
**Pretreatment** & **Parameters** & **Optimal Point** & \begin{tabular}{l} **Power Plant—** \\ **Type of Fuel** \\ \end{tabular} & \begin{tabular}{l} **Optimal Point** \\ **for CO\({}_{2}\)** \\ **NO\({}_{\rm x}\)** \\ \end{tabular} & \
\begin{tabular}{l} **Optimal** \\ **Point for** \\ **NO\({}_{\rm x}\)** \\ \end{tabular} &
\begin{tabular}{l} **Desirability** \\ \end{tabular} \\ \hline \multirow{6}{*}{Control} & Time & 48.96 & SP-NG & 8630.0 & 40.16 & \\ \cline{2-6}  & _D\({}_{\it eff}\)_ & 5.087 \(\times\) 10\({}^{-10}\) & SP-HO & 13,908.6 & 34.19 & \\ \cline{2-6}  & SEC & 13.22 & GT-NG & 10,611.2 & 25.91 & \\ \cline{2-6}  & E\({}_{\rm ef}\) & 16.92 & GT-GO & 14,220.6 & 78.56 & \\ \cline{2-6}  & Color & 24.54 & CC-NG & 6106.1 & 40.02 & \\ \cline{2-6}  & Shrinkage & 31.48 & CC-TGO & 8440.1 & 51.29 & \\ \hline \multirow{6}{*}{Ultrasound} & Time & 44.46 & SP-NG & 7218.9 & 33.59 & \\ \cline{2-6}  & _D\({}_{\it eff}\)_ & 5.90 \(\times\) 10\({}^{-10}\) & SP-HO & 11,634.3 & 28.60 & \\ \cline{2-6}  & SEC & 11.35 & GT-NG & 8876.1 & 21.67 & \\ \cline{2-6}  & EE & 19.42 & GT-GO & 11,895.4 & 65.71 & \\ \cline{2-6}  & Color & 19.36 & CC-NG & 5107.7 & 33.48 & \\ \cline{2-6}  & Shrinkage & 26.95 & CC-TGO & 7060.0 & 42.90 & \\ \hline \multirow{6}{*}{Blanching} & Time & 39.31 & SP-NG & 6225.5 & 28.97 & \\ \cline{2-6}  & _D\({}_{\it eff}\)_ & 6.50 \(\times\) 10\({}^{-10}\) & SP-HO & 10,033.3 & 24.66 & \\ \cline{1-1} \cline{2-6}  & SEC & 9.79 & GT-NG & 7654.6 & 18.69 & \\ \cline{1-1} \cline{2-6}  & E\({}_{\rm ef}\) & 21.98 & GT-GO & 10,258.4 & 56.67 & \\ \cline{1-1} \cline{2-6}  & Color & 19.08 & CC-NG & 4404.8 & 28.87 & \\ \cline{1-1} \cline{2-6}  & Shrinkage & 29.13 & CC-TGO & 6088.5 & 37 & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Results of optimization using a desirability method. emission, while the lowest CO\({}_{2}\) (4279.7 g in a CC power plant) and NO\({}_{\rm x}\) (18.16 g in a \(GT\) power plant) emissions with \(NG\) were obtained for the blanched samples with a \(ST\) of 2 mm dried at a \(MP\) of 300 W. Regarding the serious global warming crisis, knowing that the increasing population results in an ever-increasing demand for agricultural products, and considering the high energy consumption in the drying process of agricultural products, the application of different pretreatments seems to be a practical and important approach to reduce the \(SEC\) and \(GHG\) emission, hence reducing climate change. Conceptualization, E.T. and M.K. ; methodology, E.T. and M.K. ; validation, E.T. and M.K. ; formal analysis, E.T. ; investigation, E.T. and M.K. ; resources, E.T. and A.S.; data curation, E.T. and M.K. ; writing--original draft preparation, E.T. and A.S.; writing--review and editing, E.T., A.S., A.F. and M.K. ; visualization, E.T. and A.S.; funding acquisition, E.T. and A.S. All authors have read and agreed to the published version of the manuscript.