In vitro inhibition of fungi causing postharvest gray and blue molds on fresh horticultural produce by agricultural by-product extracts

Abstract

Botrytis cinerea (BC) and Penicillium expansum (PE), the causal agents of gray and blue molds on several fresh fruits and vegetables, are among the most important postharvest pathogens worldwide. Agricultural by-products can be rich in bioactive compounds, many with antifungal properties. They could be a sustainable alternative to chemical pesticides used to control postharvest fungal diseases. The extraction of value-added compounds from agricultural by-products contributes to circular economy and the EU Green Deal as well. Almond skin (AMS) and avocado seed (AVS) extracts were obtained using ultrasoundassisted extraction and their total phenolic content and total antioxidant capacity were determined. The capacity of extracts to inhibit BC and PE was investigated using a microtiter assay. AVS showed the highest inhibition capacity, with 99% inhibition of both BC and PE, while AMS inhibited BC and PE by 65 and 99%, respectively. The results suggest that the presence of phenols and antioxidants in the extracts may be responsible for the antifungal activity and that these by-product extracts have potential as novel eco-friendly antifungal agents for the management of postharvest diseases. Further in vivo studies are needed to validate these findings.