The Antioxidant Profile of Some Species of Microgreens Cultivated on Hemp and Coconut Substrate Under the Action of a Biostimulator Based on Humic Acids

Microplants are vegetables, grains and aromatic herbs that are consumed in the stage of young plants, without roots, developed after the germination stage, in the stage of cotyledons and which have a high content of nutrients (antioxidants, vitamins, minerals, fatty acids, lutein, β-carotene, proteins and fibers, etc.), which makes them functional, concentrated foods capable of feeding the world’s ever-growing population. The significant amounts of antioxidants in microgreens have the role of neutralizing free radicals and reducing their harmful impact on human health. The microgreens studied were spinach (Spinacia oleracea) cultivar ‘Lorelay’, mustard (Sinapis alba) cultivar ‘White’ and radish (Raphanus sativus) cultivar ‘Red Rambo’, tested on hemp and coconut substrates and under the influence of the organic biostimulator Biohumussol, based on humic acids. The antioxidant content of the plants was determined by analyzing total carotenoids, lycopene, chlorophyll, β-carotene, polyphenols and flavonoids, as well as the antioxidant activity by ABTS and DPPH methods. The obtained results indicated that the reaction of the plant material depends on the composition of the substrate and the presence of the applied biostimulator. The highest contents of substances with an antioxidant role were obtained from the microgreens on the hemp substrate, especially mustard and radishes, and the biostimulator proved to be compatible with the spinach microgreens.