Evaluation of Indigenous Medicinal Mushroom Mycelia for the Development of Pickering Emulsions as Sustainable Carriers of Bioactive Compounds

Fungal mycelia have emerged as promising sustainable materials in food science, due to their content of bioactive compounds and increasing application in the development of novel food and feed ingredients. In this context, mycelia from medicinal mushrooms, such as Morchella dunalii, Morchella importuna and Trametes versicolor, previously isolated from Kefalonia (Greece), were used for the development of Pickering emulsions. Initially, mycelia were produced in submerged fermentations using an aqueous extract of orange peels as the substrate. Subsequently, emulsions were prepared using powdered mycelia at different concentrations (2, 3, 4 and 5% w/w), gum Arabic and sunflower oil, whereas the control formulation contained gum Arabic, sunflower oil and Tween80. The emulsions were studied for emulsion stability (ES) at 5 °C and 25 °C for 7 days, as well as for their rheological properties. The results showed that ES values increased during storage due to phase separation, with lower ES values indicating greater stability. All emulsions containing 5% mycelium presented improved stability, with ES values ranging from 0-3.6% at 5 °C and 0-10.7% at 25 °C, compared to the control (~45% at both temperatures). The highest stability was observed for T. versicolor emulsions. All emulsions exhibited non-Newtonian, shear-thinning behavior as viscosity decreased with increasing shear rates. Among all samples, emulsions prepared with T. versicolor mycelium exhibited the highest viscosity, followed by M. importuna and M. dunalii. The higher viscosity of the T. versicolor emulsion suggests the formation of a more structured continuous phase, which is consistent with the enhanced emulsion stability. These properties are desirable for delivery systems, with the potential to enhance storage stability and enable controlled release of encapsulated compounds. In conclusion, these findings highlight the potential of valorizing indigenous fungal biodiversity for the development of sustainable emulsions as delivery systems for bioactive compounds within the framework of circular bioeconomy.