## 3 Results and Discussion
### Phytochemical Profile of Bell Pepper Pulp and Bell Pepper Processing By-Products
#### 3.1.4 Antioxidant Activity  
The antioxidant activity of bell pepper pulp and processing by-products, both fresh and after drying, was evaluated based on the DPPH radical scavenging activity as well as the ferric reducing antioxidant power (FRAP). The DPPH radical scavenging activity of yellow and red bell pepper pulp and processing by-products are summarised in Figure 3. The DPPH radical scavenging activity indicates the hydrogen donating capability of the investigated samples due to the bioactive compounds possesing antioxidant properties. The data summarised in Figure 3 shows the radical scavenging activity of the investigated samples. The values recorded for the DPPH radical scavenging activity follow the same trend as those reported for TPC and TFC. In the case of the bell pepper samples, the DPPH inhibition ranged from 70.13% to 87.25%. The highest value was recorded for the RBPP (87.25%) and the lowest for the DYBPB (70.13%). A decrease in free radical scavenging activity can be observed for fresh yellow and red bell pepper by-products (YBPB and RBPB), but they still maintain a significant level of DPPH inhibition (74.88% for YBPB and 77.59% for RBPB). Significant decreases (\(p<0.05\)  
Figure 3: DPPH inhibition (%) of yellow and red bell pepper pulp and processing by-products, fresh and after drying. Results are expressed as the mean value of three determinations \(\pm\) standard deviation (SD) indicated by the error bars. According to the \(t\)-test, different letters (a–g) represent significant differences (\(p<0.05\)) between the values represented in the columns. were also recorded for dehydrated samples compared to fresh samples, i.e., DYBPP and DRBPP (76.50% and 78.34%, respectively) but also for DYBPB and DRBPB (70.13% and 75.18%). However, a significant level of DPPH inhibition is also maintained in the dehydrated samples, and it can be concluded that, the valorisation of yellow and red bell pepper by-products is justified, as they have a high antioxidant activity. Between the two types of bell peppers, the RBPP recorded a higher percent of DPPH inhibition than YBPP for both the initial product and the by-product, but also the initial dried product and the dried by-product. The results are consistent with other studies on the radical scavenging activity of bell peppers. [PERSON] et al. [35] obtained DPPH inhibition values ranging from 59-87% for different varieties of bell peppers at different ripening stages. In the same study, the DPPH inhibition of roasted bell peppers was also evaluated, obtaining slightly lower values (31-71%), similar to our research. Similar values of DPPH inhibition were obtained by [PERSON] and [PERSON] [36] in their study on the phytochemical content of different types of bell peppers, obtaining a value of 92%. In the study on the evaluation of the free radical scavenging activity of red, yellow, and green bell peppers, [PERSON] et al. [25] reported the highest value for red bell peppers (78.5%), similar to our study, while for yellow bell peppers, it obtained 64.9%. The antioxidant activity of the samples expressed by ferric reducing antioxidant power (FRAP) is illustrated in Figure 4.  
Ferric reducing power reflects the ability of the antioxidant compounds contained in the samples investigated to donate electrons, thereby reducing oxidized intermediates of the peroxidation process [15]. The results of antioxidant activity evaluated with the FRAP assay revealed that the ferric reducing power of fresh bell pepper by-products, YBPB and RBPB, is about of 58% of the value recorded for the YBPP and RBPP. Figure 4 also shows that drying the fresh samples at a moderate temperature of 60 \({}^{\circ}\)C resulted in some losses in the FRAP value, of about 24% for DYBPP and DRBPP and of 15-17% for DYBPB and DRBPB, relative to the corresponding fresh sample values. It was found that  
Figure 4: Ferric reducing antioxidant power of yellow and red bell pepper pulp and processing by-products, fresh and after drying.