Avocado Seed Extract as a Sustainable Solution for Controlling Postharvest Citrus Molds

Postharvest fungal decay represents a major source of economic losses in the global citrus industry. This study evaluated ultrasound-assisted extracts obtained from avocado seeds (AVS), almond hulls (AMH), and olive pomace (ALP), agro-industrial by-products rich in phenolic compounds, as natural alternatives to synthetic fungicides for controlling citrus green and blue molds caused by Penicillium digitatum and Penicillium italicum, respectively.

The extracts were chemically characterized in terms of total phenolic content and antioxidant capacity. In vitro assays showed that AVS achieved 99.9% inhibition, whereas AMH and ALP displayed moderate antifungal effects against both pathogens. AVS disrupted fungal membranes, leading to leakage of cellular contents and inhibition of mycelial growth. Interestingly, concentration–response tests revealed a decrease in antifungal activity against P. digitatum at higher AVS concentrations.

Dip treatments using AVS at 8.0 mg mL−1 applied to previously inoculated oranges reduced the incidence of green and blue molds by 70% and 64% after 8 days at room temperature (20 °C), and by 70% and 24% after 4 weeks of cold storage (5 °C) followed by 7 days of shelf life at 20 °C, respectively.

Importantly, AVS treatment did not negatively impact key postharvest quality parameters such as weight loss, firmness, color, and sensory attributes, and even improved visual appearance and rind gloss. Overall, these findings highlight the strong antifungal potential and quality-preserving capacity of AVS, supporting its use as a sustainable, bio-based alternative to synthetic fungicides within a circular bioeconomy framework.

Source

Souza, R. L. de, Pérez-Gago, M. B., García-Rodríguez, A., & Palou, L. (2026). Control of citrus postharvest green and blue molds by avocado stone extract. Retrieved from

https://www.sciencedirect.com/science/article/abs/pii/S0925521426002164