The urgent need to increase the sustainability of crop production has pushed the agricultural sector towards the use of biostimulants based on natural products. The current work aimed to determine whether the preharvest application of two commercial formulations, based on a Fabaceae enzymatic hydrolysate or a blend of nitrogen sources including fulvic acids, and two lab-made aqueous extracts from Moringa oleifera leaves (MLEs), could improve yield, quality, and storability of lettuce grown in a hydroponic system, as compared to an untreated control. Lettuce plants treated with the MLEs showed significantly improved quality parameters (leaf number, area, and color), total phenolic content and antioxidant activity, and resistance against the fungal pathogen Botrytis cinerea, comparable to that obtained with commercial formulates, particularly those based on the protein hydrolysate. A difference between the M. oleifera extracts was observed, probably due to the different compositions. Although further large-scale trials are needed, the tested MLEs seem a promising safe and effective preharvest means to improve lettuce agronomic and quality parameters and decrease susceptibility to rots.

Alternative means of control are becoming increasingly relevant to the improvement of safety and the reduction of postharvest losses and waste of fruit and vegetables, especially in view of the application of the EU Greed Deal. A previous study from our research group that focused on the electrolysis process of water and was conducted using NaCl and NaHCO₃ as electrolytes proved to efficiently reduce pathogen inoculum in packinghouse washing water. In the present study, we examined the effect of the electrolyzed salt solutions (eNaCl and eNaHCO₃) produced in the same experimental conditions previously reported to be used as postharvest treatments during handling and commercialization, and/or at the consumer’s site. We tested the electrolyzed solutions, obtained in the presence or absence of the salts, against five relevant fungal pathogens in terms of conidia viability, and on various hosts in terms of rot incidence/severity. Chemical parameters of electrolyzed and non-electrolyzed solutions were also assessed. Although a different susceptibility to treatments was observed among pathogens, electrolyzed sodium chloride (eNaCl) was the most efficient treatment for preventing spore germination, as well as for minimizing fruit rot. However, a consistent control of fungal viability and consequent rot was also achieved using electrolyzed tap water (eW). The eNaHCO_3, although less efficient on fungal viability, provided a significant effect against fruit rot. The investigated electrolyzed solutions seem promising for reducing the waste of fresh fruit and vegetables.

Packaging can help prolong the shelf life of perishable agrifoods. In the present investigation, edible coatings were tested to reduce food waste caused by filamentous fungi and increase the shelf-life of high-value products such as strawberries, tomatoes, and blueberries. Different combinations of sodium alginate and calcium chloride, and various immersion times were tested on tomato as a model. The ability to activate edible coatings with food-grade compounds/extracts, such as sodium bicarbonate or Moringa oleifera extract (MLE), was explored. The extract was also tested in vitro against some of the main postharvest pathogens, such as Botrytis cinerea, Alternaria alternata, Rhizopus stolonifer, Colletotrichum acutatum, and Penicillium expansum. The most suitable composition for the edible coating proved to be 2% sodium alginate and 2% calcium chloride. MLE proved not to reduce fungal growth, except for A. alternata and C. acutatum. Concerning active coatings, particularly those containing MLE, there was a reduction in the incidence of rots on strawberries (−45%) and tomatoes (−59%) as compared to the uncoated control. Furthermore, a reduction in the severity of rots was recorded in all tested fruits (−73% in tomato, −88% in strawberries, −47% in blueberries) as compared to the uncoated control. The active edible coatings could play a role in reducing rots, contributing to the extension of the shelf-life of the selected products.