Selection of broccoli (Brassica oleracea var. italica) on composition and content of glucosinolates and hydrolysates

Abstract

Three commercial cultivars and eleven inbred broccoli lines were used to investigate the glucosinolate (GSL) profile, hydrolysate and nitrile contents, and nitrile formation rate. Glucobrassicin (BRA) and glucoraphanin (GRA) were the most dominant GSLs in all lines. The 5405 and 5406 lines exhibited the highest total GSL content (18.39 and 22.97 μmol·g−1 DW, respectively). Altogether, five lines (5306, 5311, 5312, 5404, and 5406) were selected as potential highly functional broccoli lines based on GSL content. Three lines (5405, 5406, and 5311) exhibited relatively higher total hydrolysates than the other lines. Three inbred lines (5404, 5407, and 5410) with low nitrile formation rate showed a high isothiocyanate (ITC) formation (2.29 ± 0.40, 2.16 ± 0.08, 2.24 ± 0.47 μmol·g−1 DW) and low nitrile formation (0.72 ± 0.12, 0.64 ± 0.12, 0.90 ± 0.20 μmol·g−1 DW). Therefore, lines 5404, 5407, and 5410 were selected as functional broccoli breeding lines based on their hydrolysate content and nitrile formation rates. Consequently, hydrolysate and GSL content are more reliable than GSL content only for selecting and developing highly functional varieties.