Feeding fungi plant remnants produces tasty protein to fortify vegan, vegetarian diets

As global populations continue to grow, so does the need for nutritious food and efficient manufacturing processes. Current food production practices generate side streams that could be recycled. Researchers reporting in ACS’ Journal of Agricultural and Food Chemistry fed the side streams of carrot production to fungi, generating a sustainable source of protein. They incorporated the new protein into proof-of-concept vegan patties and sausages that testers ranked as tastier than food made from plant-based proteins.

““This study is a significant step towards a circular economy by transforming valuable food side streams into a high-quality protein source, highlighting the potential of fungal mycelium in addressing global food security and sustainability challenges,” says Martin Gand, the corresponding author of the study.

About one in 11 people worldwide faced hunger in 2023, according to the United Nations, and more than three billion could not afford a healthy diet. Therefore, more sustainable and efficient food production methods must be developed. One potential solution could be edible fungi that previous research shows can grow on side streams generated by food production, such as apple pomace and whey from apple juice and cheese manufacturing, respectively. Gand and colleagues wanted to reclaim valuable nutrients in carrot side streams and repurpose them as a growth medium for edible fungi. Rather than harvest the fruiting bodies of the fungi, the researchers focused on the root-like fungal mycelia, which require less time and space to grow while still producing nutrients beneficial to humans.

Initially, Gand and colleagues screened 106 fungal strains on orange and black carrot side streams, generated during the production of natural colors, to determine which fungus grew best and produced the highest protein content. Selecting the fungus Pleurotus djamor (pink oyster mushroom), the researchers further optimized the growth conditions to improve yields. This generated proteins with biological values — which reflect how efficiently food proteins are absorbed and incorporated by the body — that are similar to those of animal and plant proteins. The P. djamor mycelia were also low in fat and comparable in fiber to those from other fungi.

To test the mycelia as a food ingredient, the researchers produced vegan patties, substituting the typical soy protein component with 0%, 25%, 50%, 75% and 100% mycelia. Taste-testing volunteers judged the food for characteristics such as texture, taste and smell. And a key takeaway was that theypreferred the 100% mycelium patties to the 100% soy patties. The volunteers then sampled vegan sausages made with either soaked chickpeas or fresh mycelia and generally preferred the smell and taste of the mycelium-containing sausages.

The results suggest that fungal mycelia are a sustainable, tasty protein source. They repurpose otherwise discarded food production materials rather than requiring additional farming, and they could offer similar nutritional benefits to plant-based proteins. Gand adds, “utilizing side streams as substrate for mycelium production reduces environmental impact while adding value and supports food security by enabling an efficient and sustainable protein production.”

The authors acknowledge funding from institutional resources and GNT Europa GmbH, a company that manufactures natural food colors.

The paper’s abstract will be available on Dec. 17 at 8 a.m. Eastern time here: http://pubs.acs.org/doi/abs/10.1021/acs.jafc.5c11223    

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