Enhanced Bioaccumulation of Essential Minerals in Filamentous Fungal Biomass During Cultivation to Produce High Quality Vegan Food

Filamentous fungi compounds have the ability to bind heavy metals; therefore, it is expected that supplementing cultivation media with essential minerals will lead to mineral accumulation in the fungal biomass. Such biomass can be considered as a food ingredient. This research aimed to investigate the effects of mineral supplementation on fungal growth and sensory properties of food products based on fungal biomass, as well as to determine the optimum supplementation concentration and harvest time. Essential minerals, including iron (Fe), zinc (Zn), and calcium (Ca), were added to the cultivation media of Rhizopus oligosporus at concentrations of 1.25-11.25, 0.50-5.25, and 50-125 mg/100 mL, respectively. The results showed that the addition of minerals at 3.75, 1.75, and 87.5 mg/100 mL for Fe, Zn, and Ca, respectively, did not significantly affect fungal growth in comparison with the control. Mineral supplementation with Fe, Zn, and Ca successfully increased the mineral content in the fungal biomass by 5, 5, and 13 times that of the biomass cultivated without supplementation, respectively. The mineral content of the biomass reached 28.26, 3.45, and 63.04 mg/100 g after 48 h of incubation for Fe, Zn, and Ca, respectively. The optimum harvesting times for Fe, Zn, and Ca were 48, 24, and 72 h, respectively. The addition of minerals did not affect the overall liking and taste of nugget made from the mineral-enriched fungal biomass. The Fourier transform infrared spectroscopy results showed that there was a new peak that represents new complexes between metal ions and functional group of the fungal biomass. This study revealed that cultivation media fortification with minerals offers a viable solution to enhance mineral content, which is often lacking in vegan diets. © 2025 Author(s). Published by Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences. This is an open access article licensed under the Creative Commons Attribution 4.0 License (CC BY 4.0) (https://creativecommons.org/licenses/by/4.0/)