Zinc biofortification improves phytochemicals and amino-acidic profile in Brassica oleracea cv. Bronco

•Zn-biofortification programme in Brassica oleracea plants.•Zn-doses induced accumulation of essential amino acids.•Increase of glucoiberin and total aliphatic and indolic glucosinolates.•Accumulation of sinapic acid derivatives, flavonols and total phenols. Zn deficiency is currently listed as a major risk factor for human health. Recently, a complimentary solution to mineral malnutrition termed ‘biofortification’ has been proposed. The aim of this study was to investigate the possible effects of a Zn-biofortification program on Zn levels, amino acidic profile and the phytochemicals content in an edible leafy vegetable, such as Brassica oleracea cv. Bronco. Our results indicate that supplementation of 80–100μM Zn is optimal for maintaining the normal growth of plants and to promote the major Zn concentration in the edible part of B. oleracea. Any further increase of Zn supply induced an accumulation of total amino acids, and increased the enzymatic activities involved in sulfur assimilation and synthesis of phenols, finally resulting in a foliar accumulation of glucosinolates and phenolic compounds. Thus, it could be proposed that the growth of B. oleracea under 80–100μM Zn may increase the intake of this micronutrient and other beneficial compunds for the human health.