The antioxidant properties of Brassica microgreens grown in different substrates

Abstract

Microgreens is a type of young vegetables with two fully developed cotyledon leaves and mostly one pair of small true leaves. Due to the young age, microgreens are known as an excellent source of vitamins, minerals and antioxidants. The selection of a suitable substrate is very important factor for accumulation of nutrients in short time as microgreens grow. The objective of our study was to evaluate the antioxidant properties of Brassica microgreens grown in different types of organic substrates. Red pak choi (Brassica rapa var. chinensis cv. ‘Rubi F1’) and tatsoi (Brassica rapa var. narinosa) microgreens were grown in greenhouse (9 days, 22/18 ± 2 °C day/night temperature, 60 ± 5 % a relative air humidity) during winter season. Three different substrates were chosen for experiments – peat (PROFI 1), coconut fibre’s (ORGANIX COCOSUBSTRATAS) and compost (Organic compost Universal). The obtained data showed that antioxidant properties of microgreens depended on substrate and varied among species. The total phenols and anthocyanin contents significantly (P ≤ 0.05) increased in both Brassica species grown in coconut fibres substrate. Meanwhile, significantly reduced content of phenols was determined in tatsoi and red pak choi microgreens grown in compost. Tatsoi grown in peat substrate accumulated more phenolic compound, however, significantly lower content of phenols in red pak choi was determined. Contrary, compost and peat substrate had no influence for accumulation of anthocyanins in red pak choi, and significantly reduced in tatsoi. The similar tendency was observed on flavonols in both microgreens species when significantly lower index was determined. Leaf flavonol index significantly increased in tatsoi, which were grown in compost, and red pak choi grown in coconut fibre’s substrate.[...]