Content of selected bioactive components and antioxidant properties of broccoli (Brassica oleracea L.)

To evaluate individual variations in broccoli VOLTA F1 plants, the bioactive components of 15 florets that were cultivated in identical agricultural and climatic conditions were analyzed. Glucosinolates were analyzed by HPLC; total phenolic compounds, ascorbic and dehydroascorbic acids (vitamin C) and the DPPH* and OH* radical-scavenging activities of samples were also determined. Florets were characterized by particularly high glucoraphanin content, 17.95 mu mol/g dry weight on average, which comprised about 50% of total glucosinolates. High individual variation was observed for several bioactive compounds, as well as for DPPH* and OH* radical-scavenging activity. Coefficients of variability (CVs) were high, and except for one case, exceeded 10%. Among glucosinolates, the highest CVs were noted for progoitrin (34.22%), 4-hydroxyglucobrassicin (27.32%) and neoglucobrassicin (24.44%). High CVs were also observed for vitamin C (29.11%), including dehydroascorbic acid (26.72%), and for OH* (25.76%) and DPPH* (21.77%) radical-scavenging activities. Smaller variations were found for glucoraphanin (CV = 14.84%) and polyphenols (CV = 14.95%).