Potato Peel as a Natural Source of Biocompounds for Cereal Fungal Control

UN 2030 Agenda for Sustainable Development and the UN Convention on Biodiversity Strategic Plan for 2020 address the need to reduce synthetic inputs in agroecosystems while decreasing industrial food waste. Peels recovered from processing varieties were profiled, obtaining extracts up to 1200 and 300 μM of total phenols and steroidal glycoalkaloids, respectively. Their antifungal activity was tested by in vitro experiments against Fusarium graminearum and Fusarium verticillioides. A comparison among raw peel extracts, their separated fractions of steroidal glycoalkaloids, phenolic acids, and anthocyanins, their combination, and mixtures of authentic molecules was performed. For all the peels tested, fungal growth was reduced independently of genotype and farming systems with a range from 12 to 30% of radial growth inhibition. While the antifungal role of glycoalkaloids was confirmed (up to 20% inhibition), for the first time, the effectiveness of phenolic acids alone was revealed (up to 30% inhibition).