## 3 Results and Discussion
### Antioxidant Potential  
This study examined the effect of \(\gamma\)-polyglutamic acid supplementation at concentrations of 0.1% and 0.5% (lupine sprouts) and 0.01% and 0.05% (kale sprouts) on the content of phenolic compounds and the antioxidant activity in the mentioned sprouts. The results obtained using both the DPPH and FRAP methods (Table 2) indicate a much higher antioxidant activity of kale sprouts compared to lupine sprouts. This is probably related to the higher content of phenolic compounds in kale sprouts than in lupine sprouts, as was determined using the Folin-Ciocalteu method. The highest value of antioxidant activity in the FRAP method was achieved by kale sprouts watered with a 0.01% PGA solution on day 8 of cultivation, while the lowest value among kale sprouts was achieved by those watered with a 0.05% PGA solution on the seventh day of cultivation. In turn, in the group of lupine sprouts, the highest value was achieved by sprouts watered with a 0.5% PGA solution on day 8. The highest value of antioxidant activity in the group of lupine sprouts was almost three times lower than the lowest value of antioxidant activity in kale sprouts, which confirms the higher antioxidant activity of the second plant (Table 2). Lupine sprouts watered with a 0.1% PGA solution achieved the highest result on day 6 of cultivation. Supplementation of lupine sprouts with a 0.5% PGA solution on days 6 and 8 of culture had a positive effect on obtaining higher results compared to sprouts watered with water or a 0.1% PGA solution on the same days. However, on the 10 th day of cultivation, both groups of sprouts watered with a 0.1% or 0.5% PGA solution obtained lower results of antioxidant activity compared to sprouts watered with water on that day (Table 2). This is related to the lower total concentrations of phenolic compounds in these groups of sprouts compared to sprouts watered with water on day 10. The highest value of antioxidant activity determined by the DPPH method was demonstrated, as for the FRAP method, for kale sprouts watered with a 0.01% PGA solution on day 8 of culture, which is related also with the highest polyphenol content determined in these sprouts. The lowest value of antioxidant activity for kale sprouts was determined using the DPPH method for sprouts watered with a 0.05% PGA solution on day 7. It is also associated with the lowest total polyphenol content in this group of sprouts. This result proves the unfavorable effect of supplementation with a 0.05% PGA solution compared to sprouts watered with water on the same day of cultivation, for which this value was almost twice as high. In the group of lupine sprouts, the highest value of the antioxidant activity measured by the DPPH method was determined for sprouts watered with water on the 10 th day of cultivation. Moreover, in this case, it can be assumed that it was caused by a higher total concentration of polyphenols. However, the highest value for lupine sprouts was 2.5 times lower than the lowest value for kale sprouts, which again confirms the higher antioxidant activity of kale sprouts (Table 2). In a similar work, [PERSON] et al. [42] examined how selenium compounds affect the antioxidant properties of kale sprouts. In the control group of sprouts, which was watered with water, the result of the FRAP method was 91.0 \(\pm\) 2.4 ug Fe\({}^{2+}\)/g d.w., which is lower compared to the results obtained in this study for kale sprouts watered with water on days 6, 7, and 8, which were equal to, respectively, 102.2 \(\pm\) 0.7 uM Fe\({}^{2+}\)/g d.w., 151.8 \(\pm\) 0.6 uM Fe\({}^{2+}\)/g d.w., 157.7 \(\pm\) 0.9 uM Fe\({}^{2+}\)/g d.w. In turn, the result of the antioxidant activity in the same work [42], using the DPPH method for the control group of kale sprouts, was 285 \(\pm\) 13 uM Trolox/g d.w. In the case of kale sprouts watered with water on days 6, 7, and 8 in the present study, this method gave the following values: 38.0 \(\pm\) 0.5 uM Trolox/g d.w., 61.1 \(\pm\) 0.2 uM Trolox/g d.w.,and 54.3 \(\pm\) 0.3 \(\mu\)M Trolox/g d.w.