## 3 Results and Discussion
### Chemical Properties
#### 3.2.2 Antioxidant Capacity  
In the case of the control samples, similarly to total polyphenolic compounds content, the antioxidant capacity measured by the ability of extracts to scavenge the ABTS radical cations and to reduce the ferric ions was stronger for snacks gained after usage of microwaves (approximately 20.5% and 28%, respectively) when compared to frying (Table 3). Addition of fruit juice powders into the pellets has no influence on the antioxidant capacity values examined by TEAC ABTS assay when chokeberry powder was applied, whereas addition of blackcurrant and cranberry powders increased the TEAC ABTS values of, respectively, approximately 31% and 22% for microwaved samples, and 22 % and 15 % for snacks gained after frying. [PERSON] et al. (2015) showed that ability of extruded corn breakfast cereals to scavenge of ABTS radical cations decrease when the concord grape, cranberry, blueberry and red raspberry powders were applied for their preparation. Interestingly, the method of snacks production (microwaving/frying) had significant influence when the blackcurrant juice powder was added that caused a difference between TEAC ABTS values of almost 30% between microwaved and fried samples. Addition of cranberry and chokeberry powders resulted, on average, in 14.3% differences, that pointed out a stronger influence of frying on blackcurrant powder's bioactive components. As the dominant group of polyphenols in this powder was anthocyanins, it can be concluded that frying caused stronger degradation of these constituents than application of microwaves at 700 W. Storage resulted in a linear decrease in TEAC ABTS values up to 5 weeks, regardless of the type of powder added. The strongest degradation of compounds able to scavenge ABTS radicals was noted in case of snacks gained after frying with 3% addition of blackcurrant juice powders (almost 30%) in comparison to non-stored products. On the other hand, in snacks gained after usage of microwaves, the decrease in TEAC ABTS values during 5-week storage was at the level of 17% which showed that frying had a stronger impact on the thermolability of bioactives in blackcurrant powder. In the case of the control samples, the decrease in antioxidant capacity values was approximately 22%, regardless of the method used for snack preparation. The addition of cranberry and chokeberry powders caused higher retention of compounds able to scavenge ABTS radical cations, thus products gained with application of these powders seems to be more stable during storage in terms of the degradation of bioactive constituents. In the case of antioxidant capacity measured by the ability of extracts to reduce the ferric ions, the addition of chokeberry, blackcurrant and cranberry powders resulted in increase in FRAP values, respectively, of 3.8%, 6.3% and 8.6%. Similarly to TEAC ABTS, the strongest impact was noted when the blackcurrant and cranberry powders were applied. Usage of microwaves at 700 W and frying also had a significant impact on the FRAP values of products obtained when the juice powders were added. The application of microwaves resulted in almost 29% higher values of FRAP when compared to samples gained after frying. This suggest a stronger degradation of compounds able to reduce the ferric ions during application of this type of pellets processing into snacks. A 5-weeks storage led to a slight linear decrease in the FRAP values for all analysed snacks. In products gained after application of microwaves the decrease was only, on average, 6.1% whereas for products gained after frying was 11.5% for snacks with fruit powders. The degradation of native components present in control samples (no fruit powders addition) during storage was at the same level (microwaves: down to 6.6%; frying down to 12.7%) which mean that native compounds present in pellets had a significant contribution to FRAP values during storage.