New food sources are explored to provide food security in sustainable ways. The submerged fermentation of edible filamentous fungi is a promising strategy to provide nutritious and affordable food that is expected to have a low environmental impact. The aim of the current study was to assess the novel use of Aspergillus oryzae cultivated in submerged fermentation on oat flour as a source for food products that do not undergo secondary fermentation or significant downstream processing. The fungus was cultivated in a pilot-scale airlift bioreactor, and the biomass concentration and protein content of the biomass were assessed. A tasting with an untrained panel assessed consumer preferences regarding the taste and texture of minimally processed vegetarian and vegan burger patties made from the biomass, and how the patties fared against established meat-alternative-based patties. The cultivation of Aspergillus oryzae resulted in a yield of 6 g/L dry biomass with a protein content of 37% on a dry weight basis. The taste and texture of the minimally processed fungal burger patties were to the liking of some participants. This was also reflected in diverse feedback provided by the participants. The cultivation of the fungus on oat flour and its utilization in developing burger patties shows its promising potential for the production of nutritious food. The applications of the fungus can be further developed by exploring other favorable ways to texture and season this relatively new functional food source to the preferences of consumers. 

Fermentation can be a powerful tool for developing new sustainable foods with increased nutritional value and fermented microbial biomass derived from filamentous fungi is a promising example. This study investigates the nutritional profile of edible Aspergillus oryzae biomass produced under submerged fermentation (SmF) using oat flour as a substrate. The fermentation occurred in a 1m³ airlift bioreactor during 48 h at 35 °C and the nutritional profile of the produced fungal biomass in terms of amino acids, fatty acids, minerals (Fe, Zn, Cu, Mn), vitamins (E, D₂), and dietary fiber was compared to oat flour as well as pure fungal biomass grown on semi-synthetic medium. The total amount of amino acids increased from 11% per dry weight (dw) in oat flour to 23.5% dw in oat fungal biomass with an improved relative ratio of essential amino acids (0.37 to 0.42). An increase in dietary fibers, minerals (Fe, Zn, Cu), vitamin E, as well as vitamin D₂ were also obtained in the oat fungal biomass compared to oat flour. Moreover, the short chain omega-3 α-linolenic acid (ALA) and omega-6 linoleic acid (LA) values increased from 0.6 to 8.4 and 21.7 to 68.4 (mg/g dry weight sample), respectively, in oat fungal biomass. The results indicate that fungal biomass grown on oat flour could have a potential application in the food industry as a nutritious source for a wide variety of products.

Since the first years of history, microbial fermentation products such as bread, wine, yogurt and vinegar have always been noteworthy regarding their nutritional and health effects. Similarly, mushrooms have been a valuable food product in point of both nutrition and medicine due to their rich chemical components. Alternatively, filamentous fungi, which can be easier to produce, play an active role in the synthesis of some bioactive compounds, which are also important for health, as well as being rich in protein content. Therefore, this review presents some important bioactive compounds (bioactive peptides, chitin/chitosan, β-glucan, gamma-aminobutyric acid, L-carnitine, ergosterol and fructooligosaccharides) synthesized by fungal strains and their health benefits. In addition, potential probiotic- and prebiotic fungi were researched to determine their effects on gut microbiota. The current uses of fungal based bioactive compounds for cancer treatment were also discussed. The use of fungal strains in the food industry, especially to develop innovative food production, has been seen as promising microorganisms in obtaining healthy and nutritious food.

The edible filamentous fungi are hot candidate for future supply of functional food and feed with e.g. protein, essential amino acids, and compounds with immunostimulant activity. L-carnitine that plays a crucial role in energy metabolism represents a functional compound normally produced by Zygomycetes filamentous fungus Rhizopus oligosporus in solid-state fermentation. The present study provides the first insights on production of L-carnitine-enriched edible fungal biomass through submerged cultivation of several Ascomycetes and Zygomycetes including Aspergillus oryzae, Neurospora intermedia, Rhizopus oryzae, and Rhizopus oligosporus. A. oryzae with 3 mg L-carnitine yield per gram of fungal biomass, indicates great potential on production of this bioactive compound which is remarkably higher than the other tested fungi in this work and also previous studies. In addition to fungal strain, other factors such as cultivation time and presence of yeast extract were found to play a role. Further studies on submerged growth optimization of A. oryzae in both high-quality recipes and in medium based on low-value substrates are proposed in order to clarify its potential for production of L-carnitine-enriched fungal biomass.