Comparative analysis of individual glucosinolates, phytochemicals, and antioxidant activities in broccoli breeding lines

The aim of this research was to evaluate the profile and concentration of individual glucosinolates (GSL), and the total phenol content (TPC), total flavonoid content (TFC), ascorbic acid content, and antioxidant activity of broccoli florets and flower stalks (10 commercial cultivars, 19 F1 hybrids, and 20 inbred lines). All broccoli heads were harvested at their marketable stage, and their flower stalks and florets were subjected to phytochemical analysis. GSL, TPC, TFC, and ascorbic acid content varied significantly depending on broccoli genotype. Altogether, nine GSLs were identified, four of which (glucoraphanin, progoitrin, glucoerucin, and glucobrassicin) were the most common in both broccoli flower stalks and florets. In florets, glucobrassicin was the most abundant GSL (4.46 μmol·g^-1 DW), followed by glucoraphanin (1.93 μmol·g^-1 DW), whereas glucoraphanin was the most abundant in flower stalks (1.47 μmol·g^-1 DW). The concentrations of total GSLs, TPC, and TFC in florets were relatively higher than those in the flower stalks, whereas the concentration of ascorbic acid was higher in the flower stalks than the florets. Almost all F1 hybrids and inbred lines exhibited higher TPC, TFC, ascorbic acid concentration, and antioxidant activities than those in the commercial cultivars. Three F1 hybrids; 5075, 5078, and 5079, and one inbred line (5308) had the highest glucoraphanin and total GSL content. Three inbred lines, 5307, 5311, and 5409 had the higher concentration of glucobrassicin and total GSLs, superior antioxidant activity with low PRO+EPI content. These results suggest that these genotype selections had desirable compositions of individual GSLs and higher nutritional value for commercialization as functional vegetables.