## 4 Discussion

Table 4: Fatty acid content (g/100 g) of pumpkin dried at different temperatures. Different letters mean that the values are statistically different for \(p\) < 0.05.  
compared to 60 \({}^{\circ}\)C. However, they observed a decrease in lutein by 68%, compared to 19% in the reported study. They also found complete degradation of violaxanthin upon drying at 25 \({}^{\circ}\)C and above [31]. [PERSON] et al. (2011) showed that by cooking pumpkin for 20 min at 100 \({}^{\circ}\)C, the content of lutein decreased by 15.5%, \(\alpha\)-carotene by 17.9% and \(\beta\)-carotene by 16.9% compared to the fresh raw material and complete disintegration of violaxanthin. In our study, the carotenoid content retained the same level when drying at 40 \({}^{\circ}\)C and 60 \({}^{\circ}\)C, and a significant decrease was observed only at 80 \({}^{\circ}\)C [27]. Despite the observed differences in individual studies, there is a tendency for the increase in temperature to cause a reduction of carotenoids and even their complete decomposition. The differences are most likely due to the research methodology being different. It is known that not only temperature affects the degradation of carotenoids. The duration of the drying process is also important, as well as the type of thermal treatment (e.g., convection, sun, vacuum drying or cooking) and pre-treatment (e.g., blanching, dipping in sulfite) [32]. Our study focused on the simplest and most popular method because we wanted the results to be widely applicable in practice. The content of carotenoids is also associated with the antioxidant properties of pumpkins. \(\beta\)-carotene and lutein, in particular, have very well-documented capabilities. The antioxidant potential of dried pumpkin is no less affected by ingredients such as vitamins C, D, E and polyphenols. The ability to inhibit the DPPH radical was compared for samples dried at 40 \({}^{\circ}\)C, 60 \({}^{\circ}\)C and 80 \({}^{\circ}\)C. Even though the values differed only slightly, similar to the content of carotenoids, statistically significantly lower antioxidant activity was observed for pumpkin samples processed at 80 \({}^{\circ}\)C compared to lower temperatures. The results of studies by other authors also confirm this. [PERSON] et al. (2021) observed a decreasing ability to inhibit the DPPH radical with increasing temperature in the 50 \({}^{\circ}\)C -70 \({}^{\circ}\)C range, and they obtained the best results for freeze-dried samples [33]. Similarly, the antioxidant power of tomato skins dried at 50 \({}^{\circ}\)C and freeze-dried did not differ, but the samples processed at 80 \({}^{\circ}\)C had negligible antioxidant value [34]. In contrast, [PERSON] et al. (2007) obtained a higher antioxidant activity from pumpkin flour dried at 70 \({}^{\circ}\)C than from freeze-dried. At the same time, they observed a 4.6\(\times\) higher content of polyphenols when the pumpkin was dried compared to freeze-dried. It is known that polyphenols have strong antioxidant activity and are relatively heat resistant [35]. [PERSON] and [PERSON] (2004) even observed an increase in the content of these compounds with increasing drying temperature, up to 200 \({}^{\circ}\)C [36]. In our study, we did not assess polyphenol content. Perhaps the variety of _Cucurbita moschata_ evaluated in the Chinese study is characterized by a higher content of polyphenols than the variety of _C. maxima_ produced in Poland. Another health-promoting ingredient of pumpkin is PUFA. Pumpkin oil is abundant in C18:2 omega-6 fatty acids; the 18:3 acid represents the omega-3 family. The total polyunsaturated fatty acids in the assessed oils from pumpkin varieties _Cucurbita maxima_ from Poland ranged from 47.5% to 57.5% [37]. PUFAs, due to the presence of unsaturated bonds, are highly sensitive to temperature, which increases lipid peroxidation. As a result of their reaction with oxygen, secondary oxidation products are formed, which can be toxic. Susceptibility to oxidation is proportional to the number of unsaturated bonds, specifically fatty acids [38].