Can Moringa Leaf Spray Treatment Increase the Nutraceutical Properties of Radish Baby Leaf?

Abstract

Among the ready-to-use products, baby leaf salads (both raw and cooked), especially those belonging to the Brassicaceae family, represent a very interesting food typology, with nutraceutical properties. Recently, to obtain products with lower levels of synthetic chemicals and to improve nutritional quality, attention has been paid to the use of natural biostimulants such as Moringa oleifera Lam. In this study, the aim was to investigate the effect of applying this natural biostimulant, at 15, 30, and 45 days from sowing, by spraying seedlings of radish (Raphanus sativus L.) each morning with Moringa oleifera leaf extract (MLE) at doses of 1:40 and 1:30 L−1 until dripping. Different morphological, physiological, and chemical parameters were determined. At harvesting time, the fresh biomass, total leaf area, and unit leaf area showed progressive increases as the dose of MLE was increased, while there were no significant difference in the dry biomass among the treatments. The quantum yield of PSII showed a significant increase in response to MLE treatments. The contents of chlorophylls and carotenoids were higher in both MLE treatments as compared with those of the control plants. The antioxidant capacity (DPPH) was not influenced by MLE treatment, while the influence was significant for total phenolic content (TPC). No significant differences were observed for the total sugar content, while the highest concentration of ascorbic acid was found with both MLE treatments; the MLE treatments did not modify the nitrate content. Therefore, MLE treatment showed a positive influence, although further studies are necessary to individuate the better doses and treatment modalities to improve the characteristics of radish baby leaf.