## 3 Results and Discussion
### The Polyphenolic Content Changes  
There was a significant increase in total polyphenol content (TPC) in green peppers as a result of cooking (9.76 GAE uM/g d.b) (in boiling water), and there was a significant increase in TPC in green peppers as a result of microwaving (7.40 GAE uM/g d.b) relative to the control (2.75 GAE uM/g d.b). However, a significant reduction in TPC was observed \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**R-Stage**} & \multirow{2}{*}{**Processing**} & **TPC** & **DPPH** & **ABTS** \\  & & **GAE uM/g d.b.** & **TXE uM/g d.b.** & **TXE uM/g d.b.** \\ \hline \multirow{4}{*}{G} & C & 2.75 \(\pm\) 0.42 a & 47.02 \(\pm\) 1.49 b & 2.69 \(\pm\) 0.66 a \\  & B & 9.76 \(\pm\) 0.11 c & 74.91 \(\pm\) 2.33 c & 5.24 \(\pm\) 1.06 b \\  & M & 7.40 \(\pm\) 0.33 b & 34.81 \(\pm\) 2.63 a & 0.89 \(\pm\) 0.27 a \\ \hline \multirow{4}{*}{Y} & C & 17.00 \(\pm\) 0.68 b & 57.10 \(\pm\) 2.04 b & 20.08 \(\pm\) 0.45 a \\  & B & 10.03 \(\pm\) 0.78 a & 82.96 \(\pm\) 4.88 c & 9.40 \(\pm\) 0.81 c \\  & M & 10.14 \(\pm\) 0.52 a & 25.03 \(\pm\) 2.13 a & 17.09 \(\pm\) 0.45 b \\ \hline \multirow{4}{*}{R} & C & 17.26 \(\pm\) 0.64 c & 79.91 \(\pm\) 2.02 b & 21.09 \(\pm\) 0.39 b \\  & B & 1.86 \(\pm\) 0.11 a & 16.08 \(\pm\) 0.57 a & 2.62 \(\pm\) 0.24 a \\ \cline{1-1}  & M & 15.37 \(\pm\) 0.69 b & 95.88 \(\pm\) 6.04 c & 29.53 \(\pm\) 0.96 c \\ \hline \multirow{4}{*}{R-stage—\(\mathrm{r}\)pening stage; G—green pepper; Y—yellow pepper; R—red pepper; C—control; B—boiling; M—microwaving; GAE—gallic acid equivalent; TXE—Trolov equivalent. Lowercase letters mean statistically significant difference between samples for same R-stage (\(p\) = 0.05); ***—\(p\) < 0.001.} \\ \cline{1-1} \cline{2-4}  & & *** & *** \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Total polyphenol contents and antioxidant activity of bell peppers of different ripening stages after boiling and microwaving. in yellow peppers (17.00 GAE \(\upmu\)M/g d.b) due to both cooking (10.03 GAE \(\upmu\)M/g d.b) and microwaving (10.14 GAE \(\upmu\)M/g d.b). The commercially available microwave oven used in our research generated non-ionizing microwave radiation (at a frequency of 2.45 GHz and a wavelength of about 120 mm), which causes intense dielectric heating [18]. [PERSON] et al. observed that the total content of polyphenols in yellow sweet pepper var. Bachata (_Capsicum annuum_ L.) subjected to hot air convection drying (at three different temperatures of 40, 50 and 60 \({}^{\circ}\)C) decreased from 784.01 mg GAE/100 g to 630.76 mg GAE/100 g [19]. Meanwhile, other results (Table 2) confirmed previous findings that yellow bell peppers contain the most water compared to the green and red peppers [20]. Therefore, the heat generated inside the yellow pepper during processing causes intense heating of the tissues, which in turn is the cause of thermal degradation of a large amount of polyphenolic compounds (Table 1). The significant reduction in TPC was observed in our research as a result of cooking (in boiling water) red peppers (1.86 GAE \(\upmu\)M/g d.b) compared to the control (17.26 GAE \(\upmu\)M/g d.b). [PERSON] et al. also showed a 13.7% reduction in TPC in red peppers that had undergone a similar heat treatment, which was traditional blanching in water [21]. Our study confirmed the highest TPC in red peppers relative to annual peppers from other stages of maturity. According to the observations of [PERSON] et al., a high processing temperature significantly reduces the content of polyphenolic compounds in the tissues of many types of plants [22]. Perhaps the reduction in TPC content due to cooking in red peppers observed in our study was due to the high proportion of heat-sensitive polyphenolic compounds compared to polyphenolic compounds contained in yellow and green peppers. A large amount of polyphenolic compounds (mainly phenolic acids) is associated with protein and carbohydrate molecules present in the cell walls of plant tissues.