Microbial Mechanisms and Sensory Outcomes of Flavor Development in Fermented Plant‐Based Proteins

Plant‐based proteins (PBPs) are increasingly recognized as sustainable alternatives to animal‐derived proteins; however, their wider adoption remains limited by undesirable sensory attributes, including beany, grassy, earthy, bitter, and astringent flavors, as well as limited umami perception. These sensory challenges arise from volatile compounds (VOCs) such as aldehydes and ketones, as well as nonvolatile compounds (non‐VOCs) including phenolics, saponins, and bitter peptides. Fermentation has emerged as an effective clean‐label strategy for improving the flavor quality of PBPs through microbial metabolism and enzymatic biotransformation. During fermentation, flavor precursors derived from proteins, lipids, and carbohydrates are converted into taste‐ and aroma‐active compounds, including amino acids, peptides, organic acids, alcohols, esters, aldehydes, ketones, and pyrazines. These transformations enhance desirable sensory characteristics such as umami, kokumi, fruity, buttery, roasted, nutty, and fermented notes while mitigating plant‐derived off‐flavors. Microbial cultures, substrate composition, fermentation conditions, and process duration influence the extent of flavor development. This review examines the principal microbial groups used in PBP fermentation, the biochemical mechanisms underlying flavor formation and off‐flavor mitigation, the sensory outcomes associated with fermentation, and the effects of key processing factors on flavor quality. The paper also discusses sensory evaluation methods and the relationships between biochemical changes and consumer perception. Finally, the paper highlights emerging opportunities in precision fermentation, microbial engineering, flavoromics, metabolomics, and advanced analytical technologies as promising approaches for designing next‐generation fermented PBPs with enhanced flavor and product appeal.