## 3 Results and Discussion
### Total Polypphenols, Carotenoids, and Antioxidant Capacity of TPW, TPW-PEEL, and TPW-SEED  
TPW has been recognized as a valuable but highly underutilized source of antioxidants, polyphenols and carotenoids, whose content highly depends on the tomato variety, origin, and the type of processing [10; 11]. Research on carotenoids is considerably more extensive than that on polyphenols, and, to date, the antioxidant profile and content of antioxidants across various fractions of TPW derived from Croatian indigenous varieties remains unexplored. Antioxidant activity and the content of TP, \(\beta\)-carotene, and lycopene in TPW is presented in Figure 3. Antiradical activity was assessed by two approaches; even though ORAC is considered more biologically relevant, it focuses more on hydrogen atom transfer antioxidants, so TEAC was also performed to take into account electron transfer reactions [69]. TP, reflecting total reducing power, was significantly higher in TPW-PEEL compared to TPW-SEED (213.5 \(\pm\) 1.5 and 69.3 \(\pm\) 0.1 mg/100 g GAE, respectively), which is consistent with the available literature data (Figure 3a). [PERSON] and [PERSON] [70] showed that the TP content of tomato peel was 66.5% higher compared to seeds and similar observations were confirmed by other authors investigating the distribution of phenolic compounds in ripe tomato [71]. A similar effect of TPW fractionation was observed in the antioxidant activity of TPW-PEEL and TPW-SEED measured by both ORAC (111.4 \(\pm\) 9.0 and 52.4 \(\pm\) 10.8 g/kg TE, respectively) and TEAC assays (55.2 \(\pm\) 0.6 and 25.0 \(\pm\) 0.2 mg/100 g TE, respectively). This outcome was anticipated, as previous studies have demonstrated a strong correlation between antioxidant capacity (e.g., TEAC) and polyphenol content, indicating that polyphenols are the primary contributors to the hydrophilic antioxidant activity in tomatoes [72]. Although vitamin C also plays a role in the antioxidant activity of tomatoes, its content in TPW obtained after subjecting ripe tomatoes to thermal processing at 90 \({}^{\circ}\)C is expected to be significantly reduced, minimizing its contribution in this context. Carotenoids also exhibit strong antioxidant activity that can be measured by the ORAC assay, offering detailed insight into radical chain-breaking potential. However, their contribution to observed ORAC levels in this case is minimal because the detection of lipid-soluble antioxidants by ORAC requires an extraction protocol specifically designed for lipophilic compounds. This was not the case in our study because applied extraction protocols for antioxidants primarily targeted hydrophilic substances; therefore, the observed ORAC values predominantly reflect the polyphenol content rather than carotenoids. TPW-70 contained somewhat higher levels of total polyphenols compared to TPW-LIO (221.4 \(\pm\) 7.0 vs. 194.4 \(\pm\) 8.7 mg/100 g GAE, respectively), which reflected on ORAC values (139.7 \(\pm\) 29.1 vs. 95.4 \(\pm\) 2.2 g/kg TE, respectively). This is consistent with available investigations showing that exposure of tomatoes to heat treatment significantly increases the content of total phenols, more specifically caffeic and p-coumaric acid, whereas the content of ferulic acid slightly decreases. Also, chlorogenic acid is not detected in fresh tomatoes, while it was the predominant phenolic acid in TPW [73]. Figure 3b shows the content of major carotenoids in TPW-lycopene and \(\beta\)-carotene. To the best of our knowledge, this is the first study to report carotenoid content in TPW derived from indigenous Croatian tomato varieties. The values we obtained fall within the ranges reported in the literature; however, they should be interpreted with caution. Namely, even though different genotypes exhibit varying levels and profiles of carotenoids, different environmental and agronomic factors often modulate carotenoid accumulation to an even greater extent [74].