## 4 Discussion
As a result of the fermentation process, regardless of the cultivar and bacterial strain used, the total carotenoid content slightly decreased. However, a higher loss rate was noted in samples fermented with the usage of _L. rhamn_s Lock 0900. Regardless of the pumpkin cultivar used, the fermentation process resulted in a significant decrease in carotenoid content in the pumpkin pulps. Among all final products, the highest content of total carotenoids was reported for the sample SMY2 (Table 6). On the other hand, [PERSON] and [PERSON] (2018) [21] found that, depending on the level of addition of pumpkin pulps based on pumpkin fruits of the American pumpkin (_Cucurbita moschata_ L.), the total carotenoid content ranged from 13.5 to 23.2 \(\upmu\)g/g in ice cream. The total carotenoid content may affect the antioxidant activity of pumpkin pulp products. However, considering the many variables which can influence the antioxidant activity results in food products, it is important to apply assays with different reaction mechanisms [53]. Therefore, in our study, due to the applied complex matrix such as vegetable sorbets, the antioxidant activity was determined by both DPPH and ABTS methods. The previous studies [54; 55] demonstrated that pumpkin cultivars can vary considerably in terms of antioxidant activity, which is the result of a large variation in the content of bioactive compounds. Results obtained in our study show that fermentation improved the ABTS and DPPH antioxidant capacity in probiotic frozen desserts (Figure 2). [PERSON] et al. (2020) [56] also reported that the antioxidant activities based on DPPH method were enhanced during fermentation of apple juice with addition of selected bacterial strains of LAB. The authors suggested that the improvement of antioxidant capacity of fermented products was related to the increase in caffe acid and phlorizin contents. The antioxidant activities in the investigated functional frozen desserts cannot be attributed to their total carotenoids content (Tables 6 and 7), which was clearly decreased as a result of lactic acid fermentation. The improvement the ABTS and DPPH antioxidant capacity in fermented pumpkin pulps and frozen desserts can probably be associated with the fermentation process and actions of other antioxidant compounds such as phenolic compounds present in the fermented semi product--pumpkin puree and their mutual interactions. Some authors [57; 58] indicated that phenolic and flavonoid compounds are responsible for the antioxidant activity of the pumpkin extracts. Investigating these issues will be certainly the aim of our further study. The prepared pumpkin sorbets can be recognized as a functional food, taking into account the high addition of live probiotic bacteria, as well as high antioxidant activity and carotenoid compounds. An important factor which cannot be ignored in food product development strategies is the assessment of sensorial attributes, which may be important from the consumer point of view. Lactic acid fermentation by modifying the chemical composition of the raw materials affects the sensory properties of food [59]. Taking into consideration the technological aspects, the use of a fruit addition in the manufacture of frozen desserts results in favorable changes to certain sensory qualities such as taste, texture or color [60]. In the case of vegetables, the yellowness and redness are attributed to the presence of carotenes [61]. In the presented study, it was found that color properties of the investigated pumpkin sorbets were significantly affected by the used semi-product, fermented pumpkin pulp (Tables 6 and 7). The changes observed in \(\Delta\)E in pumpkin pulps PPMY, PPM (Tables 6 and 7) were slight but could be due to boiled water replacing the intercellular air during processing steps and cellular content leaking into the water due to rupture of the cell membrane, as explained by [PERSON] et al., 2006 [62].