Insights into the phytochemical composition of selected genotypes of organic kale (Brassica oleracea L. var. acephala)

Seven genotypes of kale (B. oleracea L. var. acephala), selected from a collection set up in the framework of the BRESOV H2020 Project, aimed at breeding under organic conditions, were analysed for the content in the characteristic phytochemicals of Brassica spp. The presence of prebiotic oligosaccharides was an important characteristic of this crop, with values ranging from 4.2 to 10.8 g/100 g d.w. The other detected soluble sugars were sucrose, glucose, and fructose, with glucose predominating (3.9-9.0 g/100 g d.w.). Sulphur compounds, such as sulphoxides, were detected in the form of pyruvic acid, their catabolic product (36-154 mg/100 g d.w.). In addition, the levels of main breakdown products of glucosinolates, such as sulforaphane and indole-3-carbinol, were found to be in average contents of 6.7 and 3.9 mu mol/g d.w., respectively. Finally, the presence of major phytochemicals in kale, such as polyphenols and carotenoids, reported considerable concentrations (around 1400 mg/100 g d.w. and 19 mg/100 g d.w, respectively), typical for this Brassica crop.