Investigating the Antioxidant and Color Properties of Bee Pollens of Various Plant Sources

In our study, Central and Eastern European bee pollens of different botanical origins were compared, based on their antioxidant and color properties. Total phenolic content (TPC), total flavonoid content (TFC), and in vitro antioxidant capacity (by FRAP, CUPRAC, ABTS⋅⁺ and DPPH⋅ assays) were determined spectrophotometrically. Besides, Relative Antioxidant Capacity Indexes (RACI) were calculated. CIELAB color parameters (L*, a*, b*, chroma) were determined by using a tristimulus-based instrument. Potential correlations between the investigated parameters were also identified. Based on the results of the preliminary study, ethanol:distilled water (60 : 40) was chosen as an extraction solvent. The total phenolic content of our samples ranged between 9.41 and 27.49 mg GAE/g dw. Pollens showed TFC:TPC ratios between 9 and 44 %. RACI values indicate that rapeseed (Brassica napus), traveller's joy (Clematis vitalba) and phacelia (Phacelia tanacetifolia) pollens have relatively high, while pollens of certain plants of the Asteraceae family possess low antioxidant potential. Antioxidant properties correlated significantly in most cases. RACI values showed strong positive correlation with each of the other antioxidant capacity parameters, suggesting that this approach is well applicable for comparing the antioxidant potential of bee pollens. No clear correlation was found between the antioxidant and color parameters.