Mycelium Sausages and Burgers: The Future of Plant-Based Food

Mycelium, often overlooked in favor of the more conspicuous fruiting body of the mushroom, possesses indeed extraordinary properties that make it ideal for creating structured foods. Its fibrous architecture and ability to grow in predetermined forms transform it into a versatile and sustainable raw material. Through advanced biotechnological processes, it is possible to guide the growth of mycelium to obtain food tissues with textures similar to those of meat, opening innovative scenarios for the food industry and for consumers increasingly attentive to sustainability and health.

What is mycelium and why it's ideal for plant-based sausages

Mycelium represents the least known but most essential part of the fungal kingdom. While the fruiting bodies of mushrooms capture our attention with their shapes and colors, it is underground that the real magic develops: an intricate network of microscopic filaments called hyphae that, intertwining, give life to the mycelium. This structure is not simply a root system, but a true organism that can extend for hectares, communicate and exchange nutrients with plants, and survive in extreme conditions. Its fibrous architecture and ability to form complex three-dimensional networks make it particularly suitable for creating structured foods like plant-based sausages.

The microscopic structure of mycelium

Examining the structure of mycelium under a microscope reveals a fascinating world of connections and symbioses. The hyphae, which are the individual filaments that compose the mycelium, grow by apical extension, a process that allows them to explore the surrounding environment in search of nutrients. This directional growth can be guided under controlled conditions to obtain specific structures. The cell wall of the hyphae is composed mainly of chitin and chitosan, polymers that confer resistance and flexibility, fundamental properties when it comes to recreating the texture of meat in plant-based sausages. The presence of these natural fibers allows obtaining a final product with a chewiness similar to that of traditional meat, without the need for artificial additives or binders.

Technological properties of mycelium in food production

The technological properties of mycelium make it a remarkable ingredient for the food industry. Its ability to form a three-dimensional network during fermentation in bioreactors allows for the creation of food tissues with mechanical characteristics similar to those of muscle meat. This network can be manipulated by varying parameters such as temperature, humidity, substrate composition, and the fungal strain used, offering unprecedented control over the final texture of the product. The versatility of mycelium allows for the production of not only sausages but a whole range of plant-based products with diversified textures, from more compact burgers to more fibrous poultry substitutes.

Table: comparison between mycelium properties and other plant proteins

The production process of mycelium sausages

The production of mycelium-based sausages represents a fascinating fusion between biotechnology and food tradition. This process, which transforms a simple microorganism into a complex and structured food product, is based on solid scientific principles but applied in an innovative way. Unlike the production of traditional sausages, which requires the slaughter of animals and the processing of their meats, the production of mycelium sausages begins in the laboratory, with the selection and multiplication of specific fungal strains, then developing in bioreactors of different sizes, up to industrial plants where the mycelium is transformed into finished products. The entire process requires rigorous control of numerous parameters, from the purity of the strain to the composition of the growth substrate, to the fermentation conditions.

Selection and preparation of fungal strains

The selection of the fungal strain represents the most critical phase of the entire production process. Not all fungi are suitable for food production, and among the edible ones, only some possess the necessary characteristics to create products with meat-like textures. The most used strains mainly belong to the genera Fusarium, Neurospora and Agaricus, selected for their growth speed, nutritional profile and structural properties. Each strain undergoes careful molecular characterization to guarantee its food safety and genetic identity, following rigorous protocols that resemble pharmaceutical ones more than traditional food ones. Once the optimal strain is identified, it is multiplied under conditions of absolute sterility, first in Petri dishes and subsequently in small-scale bioreactors, creating a starter for large-scale production.

Solid state and submerged fermentation

There are two main approaches for cultivating mycelium for food purposes: Solid State Fermentation (SSF) and Submerged Fermentation (SmF). Solid state fermentation simulates the natural growth conditions of fungi, with the mycelium developing on a moist solid substrate, typically consisting of bran, sawdust or other agricultural waste. This method produces mycelium with a more complex and fibrous structure, ideal for products that need a pronounced texture like sausages. Submerged fermentation, on the other hand, occurs in an agitated liquid nutrient broth, where the mycelium grows in the form of balls or aggregates. This second method allows for more precise control of growth parameters and faster production times, but produces a less articulated structure, more suitable for burgers or meatballs. Many companies are developing hybrids between these two approaches, trying to combine the advantages of both.

Table: fermentation parameters for different fungal strains

Transformation of mycelium into food product

Once the mycelium has reached the desired density and structure, it is harvested and subjected to a series of treatments that transform it into a food product. The first step is generally thermal inactivation, which stops the growth of the fungus and guarantees its microbiological safety. Subsequently, the mycelium is pressed to remove excess water and concentrate the proteins. At this point, depending on the desired final product, the mycelium can be textured through extrusion processes, which align the fibers to simulate the structure of muscle meat. For sausages, the mycelium is often combined with other ingredients such as spices, vegetable fats and natural binders, then stuffed into edible or synthetic casings. The final phase is pasteurization or cooking, which stabilizes the product and develops its flavors.

For more information on biotechnological processes applied to food production, we suggest visiting the website of the Italian National Health Institute (Istituto Superiore di Sanità), which offers updated scientific documentation on the food safety of new technologies.

Nutritional properties of mycelium sausages

Mycelium sausages do not simply represent a plant-based alternative to traditional meat, but a food with distinctive and often superior nutritional characteristics in many aspects. The nutritional profile of mycelium varies depending on the fungal strain used, the growth substrate and the fermentation conditions, but in general it is characterized by an excellent protein content, a low fat content and the presence of unique bioactive compounds. Unlike many plant proteins that require specific combinations to achieve a complete amino acid profile, mycelium proteins contain all the essential amino acids in balanced proportions, making them qualitatively comparable to animal proteins. Furthermore, mycelium is naturally rich in fiber, B vitamins and minerals such as selenium and potassium.

Amino acid composition and protein quality

The quality of a food protein is determined mainly by its amino acid profile and digestibility. Mycelium proteins show a complete amino acid profile, with particularly high contents of lysine, an essential amino acid often deficient in cereal proteins. The Protein Digestibility-Corrected Amino Acid Score (PDCAAS) of mycelium proteins approaches 1.0, the maximum possible, indicating a protein quality comparable to that of egg or milk. This makes mycelium sausages an excellent protein source for vegetarians, vegans and anyone looking to reduce meat consumption without compromising the intake of essential nutrients. The digestibility of mycelium proteins is further improved by fermentation processes, which partially pre-digest the proteins, making them more accessible to human digestive enzymes.

Fiber content and bioactive compounds

One of the most interesting aspects of mycelium sausages is their fiber content, which clearly distinguishes them from traditional sausages and many other plant-based alternatives. The fibers of mycelium are mainly composed of chitin and beta-glucans, polysaccharides with demonstrated beneficial effects on health. Beta-glucans, in particular, are known for their ability to modulate the glycemic response, reduce cholesterol and support immune health. Regular consumption of beta-glucans is associated with a reduced risk of cardiovascular and metabolic diseases, making mycelium sausages not simply a substitute food, but a functional food with health-promoting properties. Furthermore, mycelium contains ergothioneine, a unique antioxidant with powerful cytoprotective properties, not present in most plant or animal foods.

Table: nutritional comparison between mycelium sausages, pork sausages and soy sausages (values per 100g)

Considerations on nutrient bioavailability

A crucial aspect often overlooked in the nutritional analysis of foods is the bioavailability of nutrients, i.e., the fraction actually absorbed and utilized by the body. Mycelium sausages present interesting characteristics from this point of view. The fermentation processes used in their production naturally reduce the content of antinutrients such as phytates and tannins, which in many plant proteins can compromise the absorption of minerals like iron and zinc. The iron present in mycelium, although in the non-heme form typical of plants, shows a bioavailability higher than that of many other plant sources, probably due to the absence of absorption inhibitors and the presence of promoting compounds. Similarly, the zinc in mycelium is more bioavailable than that in cereals and legumes, making these sausages a nutritionally valid option for preventing deficiencies in diets devoid of animal products.

Environmental impact of mycelium sausage production

In an era of growing concern about the sustainability of the global food system, mycelium sausages emerge as a promising solution to reduce the environmental impact associated with protein production. Animal farming, particularly that of cattle and pigs, contributes significantly to greenhouse gas emissions, water consumption and deforestation. Fungal proteins, on the other hand, can be produced with a drastically lower environmental impact, representing a way to reconcile the human need for protein with the need to preserve planetary ecosystems. The life cycle analysis of mycelium sausages reveals multiple environmental advantages, ranging from the reduction of climate-altering emissions to the more efficient use of resources such as land and water.

Greenhouse gas emissions and energy consumption

The comparison between the greenhouse gas emissions of traditional sausages and those of mycelium is particularly illuminating. While the production of pork sausages generates between 5 and 7 kg of CO2 equivalent per kg of product, mycelium sausages generally emit less than 2 kg of CO2 equivalent per kg. This reduction of 80% or more in emissions is mainly due to the absence of enteric fermentation (the production of methane by animals) and the lower need for nitrogen fertilizers, whose production is extremely energy-intensive. Furthermore, mycelium fermentation processes can be powered by renewable energy sources and often generate less waste, which would otherwise require energy for disposal. Some pioneering plants are even implementing heat recovery systems generated during fermentation, further reducing overall energy consumption.

Land use and conversion efficiency

The efficiency with which different protein sources use land represents a crucial parameter in evaluating their sustainability. The production of pork sausages requires on average 8-12 m² of land per kg of protein, considering both land for farming and land for feed production. Mycelium sausages, on the other hand, require less than 1 m² of land per kg of protein, thanks to the possibility of producing mycelium in vertical bioreactors that multiply the effective production surface. This unprecedented efficiency in land use could free up millions of hectares currently destined for feed production, which could be reconverted to forests or other natural ecosystems, contributing to biodiversity conservation and atmospheric carbon capture. Furthermore, unlike traditional agriculture, mycelium production does not require fertile land and can be located near urban centers, further reducing the ecological footprint linked to transport.

Table: comparison of environmental impact between different protein sources

Use of by-products and circular economy

One of the most innovative aspects of mycelium sausage production is the ability to use various agricultural and industrial by-products as growth substrates that would otherwise represent waste to be disposed of. Bran, straw, rice husks, distillery slops and even food industry waste can be valorized as nutrients for mycelium, transforming potential waste into resources. This characteristic positions mycelium production as a pillar of the circular economy, where material flows that traditionally follow a linear path (production-use-disposal) are redirected towards closed cycles that minimize waste. Furthermore, after harvesting the mycelium, the residual substrate, enriched with enzymes and bioactive compounds, can be used as an agricultural amendment or animal feed, creating additional value and completely closing the production cycle.