## 3 Results and Discussion
### Quality of Products
The application of ultrasound-assisted convective drying (CVUS) caused better retention of (+)-catechin, (\(-\))-epicatechin, procyanidins, and chlorogenic acid compared to the convective process (CV). The positive effect of microwave application during convective drying was also observed in the case of flavian-3-ols and phenolic acid retention in dried apple cubes. The CVMW1 and CVMW2 schedules caused significant increases in the content of (+)-catechin (about 30-23%), (\(-\))-epicatechin (27-15%), procyanidins (38-33%), and chlorogenic acid (22-17%) compared to convective drying (CV). When used separately, ultrasound and microwave during the drying of apple cubes had a better effect on the content of phenolic compounds than the program that combined both ultrasound and microwave (complex schedule). Figure 8 shows a radar chart summarizing the evaluation of each drying program in terms of kinetics (drying rate and diffusion coefficient) and energy intensity (specific consumption). Each program was scored on a 1-5 point scale (worst-best) in each of the scored categories. The farther a given program was from the center of the graph, the better the score it received in the evaluation. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**No**} & \multirow{2}{*}{**Symbol**} & \multicolumn{3}{c}{**Flavan-3-ols**} & \multicolumn{3}{c}{**Dihydrochalcons**} & \multicolumn{2}{c}{**Phenolic Acid**} \\ \cline{3-8}  & & **Cat** & **Ecat** & **Proc** & **PhXg** & **Ph** & **Chl** \\ \hline
1 & CV & 67.3 a & 240.0 a & 499.0 a & 44.4 a & 58.6 a & 267.5 a \\
2 & CVUS & 73.5 ab & 277.9 ab & 603.4 bc & 44.1 a & 58.2 a & 297.5 a\(-\)c \\
3 & CVMW1 & 87.7 c & 303.90 b & 663.8 c & 47.4 a & 57.7 a & 325.5 c \\
4 & CVMW2 & 83.1 bc & 276.6 ab & 690.5 c & 46.0 a & 55.6 a & 313.9 bc \\
5 & CVMWUS & 71.6 ab & 248.2 a & 557.8 ab & 45.8 a & 53.0 a & 278.7 ab \\ \hline \hline \end{tabular} Different letters in the column indicate statistically significant difference at \(p\) < 0.05, according to [PERSON] post-hoc test. Abbreviations: Cat, (+)-catechin; Ecat, (\(-\))-epicatechin; Proc, oligomeric procyanidins; PhXg, phloretin xyloglucide; Ph, phlprioridine; Chl, chlorogenic acid.  
\end{table} 
Table 5: Effects of particular schedules of drying on polyphenol composition [mg/kg DM] in dried apple cubes. Figure 7: Total polyphenol content of TPC (mg/kg DM) in dried apple cubes produced by particular schedules of drying. Different letters above the bars indicate statistically significant differences at \(p\) < 0.05, according to [PERSON] post-hoc test. The location of the points on the graph is important, but so is the distribution of the points within the different categories for a given process. The smaller the spread, the more balanced the process. The balance can be positive if all the points are around a rating of 5-6, or negative if they are 1-2. An example of a positive process is CVMW2, which scored 5 in almost all categories. Only the TPC scored lower than the CVMW1 process. A negative balance is observed for the CV convection program, in which all parameters received the lowest rating. The influence of ultrasound (CVUS) is indirect, and most of the parameters were rated 2-3. The results obtained clearly indicate that microwaves are a positive factor in the evaluated areas (kinetics, energy intensity, and quality). Obviously, the study should be expanded to include new parameters to obtain a more complete picture of the effects of radiation. It is worth noting the slight difference between the CVMW1 and CVMW2 processes. However, the use of lower microwave power does not bring any advantages, so it can be concluded that running the processes at higher microwave power will be more beneficial.