Novel biotechnological approaches to grow Medicinal Mushrooms on maize residues and their application in breadstick

Aim: The increasing attention towards innovatives food processing, aimed at valorizing agro-food residues and improving the nutritional quality of foods, is the driver of the study. Medicinal mushrooms (MMs) are gaining attention for their interesting content of bioactive compounds whose biological activities are relevant for human health. The research aims at developing a high value-added ingredient with interesting nutritional properties, obtained by growing MMs on maize residues. Investigation focused on the analysis of MMs growth in solid state fermentations (SSFs) and how bioactives are maintained up to the production of the functional ingredient (FI) and the final gluten-free breadstick. Method: Cobs from four maize landraces cultivated in Northern Italy and the reference B73 inbred line were used to set up Solid State Fermentations systems (SSFs) for the growth of two MMs strains: Pleurotus ostreatus ATCC96997 and Ganoderma annularis DSMZ9943. Fungal growth was measured by image analysis techniques. Proximate composition and bioactive compounds of FI were determined after sample stabilization and powdering. Breadsticks with FI (obtained using Ganoderma on either Rostrato Rosso di Rovetta and B73) and without were produced and characterized from a tecnological and nutritional point of view. Results: Pleurotus and Ganoderma were able to grow on all corncobs but the type of cobs affected the Mycelial Growth Rate (0.57-10.4% MGR week-1). The image analysis technique proved appropriate to monitor the surface mycelial growth in SSFs. The cob-MM matrix showed high protein and low free sugar contents; the presence of -glucans was also detected. The addition of FI resulted in well-structured breadsticks, characterized by lower total starch, higher protein, fiber and phenolic contents, as well as higher antioxidant capacity than reference breadsticks. Product with the cobs can boast the Nutritional Claims “high in fibre” (9 g/100g of fibre). Conclusion: These study is of practical importance for the recovery of a lignocellulosic by-products that can be successfully utilized by MMs to grow. Results proved that FI could be used to develop healthier food with interesting technological and nutritional features. Acknowledgements: This study was supported by Università degli Studi di Milano, PSR 2020 - Linea 3 Seal of excellence.