Total and individual glucosinolate contents in inflorescences of eight broccoli cultivars grown under various climatic and fertilisation conditions

Abstract

Total aliphatic, indolic and aromatic glucosinolates were evaluated in the edible portions of fresh harvested inflorescences of five commercial and three experimental broccoli (Brassica oleracea L var italica) cultivars grown under various climatic and agronomic conditions, ie early (winter) or late (spring) season with poor (15 kg ha-1) or rich (150 kg ha-1) sulphur fertilisation, in an attempt to identify differences due to genetic and agronomic factors. The predominant glucosinolates in all broccoli cultivars were 4-methylsulphinylbutyl-glucosinolate (glucoraphanin), 3-indolylmethyl-glucosinolate (glucobrassicin) and 1-methoxy-3-indolylmethyl-glucosinolate (neoglucobrassicin). The results showed no significance differences in total glucosinolates between rich and poor fertilisation, whereas total glucosinolates were detected more significantly in the late than in the early season. All broccoli cultivars showed a higher content of indolic glucosinolates than aliphatic glucosinolates. Clear advantages were detected in the analysed commercial cultivars, as the experimental cultivars yielded lower concentrations of these compounds.