Preharvest Application of Commercial Products Based on Chitosan, Phosphoric Acid Plus Micronutrients, and Orange Essential Oil on Postharvest Quality and Gray Mold Infections of Strawberry

Abstract

Strawberry is a perishable fruit with a limited shelf life after harvest due to deterioration of quality and the development of gray mold, Rhizopus rot and other minor diseases. In this study, the effectiveness of commercial compounds based on chitosan, phosphoric acid plus micronutrients, and sweet orange essential oil (EO) in reducing decay and optimizing the quality of strawberries was analyzed. The plant canopy of a greenhouse crop was sprayed once and strawberry fruit were harvested three days later. Gray mold infections were evaluated after chilled storage for seven days at 4 ± 0.5 °C followed by five days shelf life. The qualitative parameters were recorded at harvest (initial day) and after three days of storage at room temperature (RT, 20 °C) or after cold storage and shelf life (CS, 4 °C). The application of sweet orange EO increased the antioxidant and flavonoid content at harvest, while a decrease was reported following three days of storage at RT. At the same time, increased ethylene production and weight loss were observed during CS three days after harvesting. Chitosan treatment maintained the harvest fruit quality and was effective in the control of postharvest decay. Our results suggest that the investigated natural compounds could improve strawberry quality after harvest. Since chitosan performed best in terms of maintaining quality and reducing postharvest decay, it could be considered as a good substitute for chemical-synthetic fungicides for the preservation of strawberry postharvest gray mold.

The Preharvest Application of Essential Oils (Carvacrol, Eugenol, and Thymol) Reduces Fungal Decay in Lemons

“…Therefore, the increase in the polyphenol concentration could be directly related to the antifungal capacity that the EOs are providing the lemons with, since polyphenolic compounds play an important role in their accumulation in vegetable tissues as a protection mechanism against biotic and abiotic stress [56]. Indeed, previous results in preharvest have shown an increase in the TPC of strawberries [32,38,39]. This increase has been associated with the fact that applying EOs to the surface of the fruits and leaves on the tree may induce a stressful environment, resulting in an increase in the shikimic acid and phenylpropanoid metabolism pathways, enhancing the defence system of the plant [61].…”

“…Moreover, evaluating the effect of pure EOs, instead of the whole plant extract, has also been demanded by many researchers due to the differences detected in antifungal efficacy when the whole plant extract is applied [31,32]. Only a few studies have been carried out in preharvest, such as those on tomatoes [33,34], lettuce [35][36][37], and strawberry [38,39]. However, there is no literature available on citrus fruit in preharvest.…”

Are Basic Substances a Key to Sustainable Pest and Disease Management in Agriculture? An Open Field Perspective

“…In an integrated program lasting two years, chitosan-treated "Chardonnay" wine grapes exhibited a degree of disease severity at harvest that was more than halved compared to the untreated control and was as effective as the synthetic fungicide program [65]. Chitosan has also been combined with active antimicrobial substances, such as essential oils, and applied as pre-harvest treatments [66] or as post-harvest coatings to improve the preservation of qualitative parameters and reduce the product losses caused by Botrytis spp. A possible evolution in the application of chitosan is its formulation as nanoparticles, which in preliminary trials behaved better than standard formulations [63].…”