The limited consumer acceptance of alternative proteins is often rooted in their flavour profile—characterised by unpleasant off-notes, a lack of savoury depth, and the absence or distortion of familiar meat-like flavours. This talk will present an overview of flavour formation in plant-based and mycelial-based protein systems, examining the chemical and biochemical origins of off-notes. It will explore the challenges of creating authentic meat flavours in plant-based meat analogues, and the importance of in situ flavour generation, particularly via Maillard chemistry and flavour protein interactions.

The talk will also present two case studies of solid-state fermentation (SSF) to enhance flavour in upcycled protein-rich by-products. The first used Rhizopus spp. to ferment brewers’ spent grain, significantly improving its flavour by generating umami, savoury, and smoky notes while modulating bitterness. Volatile analysis (SPME-GC-MS) combined with sensory profiling revealed that fermentation time influenced aroma characteristics, allowing fine-tuning of flavour outcomes. The second study explored SSF of surplus bread crusts and perennial ryegrass with three fungal strains. Fermentation reduced undesirable vegetal and sulfurous odours, while increasing pleasant bakery-like aromas. Principal component analysis linked specific volatiles to substrate and strain, and a predictive model of aroma perception was validated against trained panel results.

Finally, the PLANTOMYC project will be introduced. The aim of this project is to create hybrid meat alternatives combining plant-based materials with mycelial protein biomass. The project will focus on integrated flavour development, including valorisation of by-products as flavour precursors, to achieve both sustainability and sensory appeal.