## 4 Comprehensive Review
### A Comprehensive Overview of Bioactive Compounds in Different Food Drying Systems
#### 4.1.5 Cold Plasma
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**No.** & **Pretreatment** & **Drying Method** & **Material** & **Main Findings** & **Reference** \\ \hline \multirow{4}{*}{1} & Dielectric Barrier & Convective drying & _Tucum_\# & Regardless of the pretreatment, a (_Astrocarum_ & reduction was observed in both \\  & Discharge (DBD) & cold plasma & velocity of 0.5 m/s & _calculate_) & \(\beta\)-carotene and total phenolic content. & \\  & & & & & The compounds crocin, safanal, & \\  & Dielectric Barrier & Convective drying & \multirow{2}{*}{Saffron flowers (_Crocus sativ_)} & \multirow{2}{*}{glycerol, and total phenolics were analyzed. A 30 s pretreatment yielded} & \multirow{2}{*}{[96]} \\  & Discharge (DBD) & & 1.5 m/s & & higher values for all compounds \\  & & & & compared to the control. & \\  & & Conventional & & The combined treatment of 60 s plasma & \\  & Gliding Arc & convective drying & Fresh & pretreatment and ultrasound-assisted & \\  & Discharge & (50 \({}^{\circ}\)C, 1 m/s) and & goldenberries & convective drying resulted in the best & \\  & cold plasma & ultrasound-assisted & (_Physalis pervinana_ & bioactive compound retention, including \\  & & & & vitamin C (80.87\%), total phenolics & \\  & & & & (85.57 mg GAE/100 g dry matter), and & \\  & & convective drying & & antioxidant capacity (27.06\%). & \\  & Dielectric Barrier & & & Grape & Cold plasma treatment increased total \\
4 & Discharge cold & – & (_Vits vinifera_ L) & phenolic content by up to 22.8\% and & \\  & plasma reactor & & & pomace & antioxidant capacity by up to 34.7\%. & \\  & & & & Without cold plasma, total phenolics (TP) & \\  & & & & and antioxidant capacity (AC) were & \\  & & & & & 174.15 mg GAE/100 g DM and & \\  & High-voltage & Traditional & & 122.53 mg QE/100 g DM (convective) & \\  & plasma with 64-pin & (70 \({}^{\circ}\)C, 2 m/s) and & Apple slices (_Malus domestic_) & and 314.74 mg GAE/100 g DM and & \\  & multi-electrode & refrigerator window & (_Malus domestic_) & 220.94 mg QE/100 g DM (refactive & \\  & configuration & & drying & & window). With plasma pretreatment, & \\  & & & drying & & these values increased to approx. 270 and & \\  & & & & & 180 (convective) and 450 and 340 & \\  & & & & & (refactive window), respectively. & \\  & & & & Samples treated with plasma-activated & \\  & & & & water followed by vacuum drying had & \\  & Steam blanching & Vacuum drying & & & the highest total phenolics & \\  & and cold & and traditional & Centella & (35.049 mg GAE/g DW) and flavonoids & \\  & plasma-activated & convective drying & (_Centella asaittica_ L) & (311.274 mg QE/g DW), followed by & \\  & water (DBD type) & at 40, 50, and 60 \({}^{\circ}\)C & & those dried convectively. Antioxidant & \\  & & & & capacity was similar for both & \\  & & & & pretreatments (\(\sim\)4021.462 ug TE/g DW) & \\  & & & & and higher than untreated samples. & \\  & & & & Pretreated samples showed higher levels & \\  & & & & of total phenolics and flavonoids & \\  & & & & compared to untreated ones: & \\  & & & & & 35.75 mg GAE/g DW and & \\
7 & Steam blanching & & (_Centella asaittica_ L) & 306.573 mg QE/g DW (plasma water), & \\  & and cold & & & 32.681 mg GAE/g and & 297.573 mg QE/g \\  & plasma-activated & & & & (steam), and 31.689 mg GAE/g and & \\  & water (DBD type) & & & & 285.317 mg QE/g (untreated). & \\  & & & & All gas treatments led to higher total & \\  & & & & phenolic and antioxidant values & \\  & & & & compared to control. Phenolic content & \\
8 & High-voltage & & & & (mg GAE/g DW): air (0.949), Ar (0.947), & \\  & atmospheric cold & & & pomace & He (1.025), N\({}_{2}\) (1.033). Antioxidant & \\  & plasma (ir, Ar, He, N\({}_{2}\)) & & & capacity (mg TE/g DW): air (0.85), & \\  & & & & & Ar (0.85), He (0.85), and N\({}_{2}\) (0.89). & \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Applications of cold plasma as a pretreatment associated with drying technologies in food matrices. et al.