Variation of glucosinolates and nutritional value in nabicol (Brassica napus pabularia group)

Glucosinolate levels in leaves were determined in a collection of 36 varieties of nabicol (Brassica napus pabularia group) from northwestern Spain grown at two locations. Crude protein, acid detergent fibre, and sensory traits were also assessed by a consumer panel. The objectives were to determine the diversity among varieties in total glucosinolate content and glucosinolate profile and to evaluate their sensory attributes in relation to glucosinolate content for breeding purposes. Eight glucosinolates were identified, being the aliphatic glucosinolates, glucobrassicanapin, progoitrin, and gluconapin the most abundant. Glucosinolate composition varied between locations although the glucosinolate pattern was not significantly influenced. Differences in total glucosinolate content, glucosinolate profile, protein, acid detergent fibre, and flavour were found among varieties. The total glucosinolate content ranged from 1.4 mu mol g(-1) to 41.0 mu mol g(-1) dw at one location and from 1.2 mu mol g(-1) to 7.6 mu mol g(-1) dw at the other location. Sensory analysis comparing bitterness and flavour with variation in glucosinolate, gluconapin, progoitrin, and glucobrassicanapin concentrations suggested that other phytochemicals are probably involved on the characteristic flavour. The variety MBG-BRS0035 had high total glucosinolate, glucobrassicanapin, and gluconapin contents at both locations and could be included in breeding programs to improve the nutritional value of this vegetable crop.