Advances in microbial metabolism for flavor development: Exploring the roles of bacteria, yeasts, and molds in food applications
Fardis Malekijahan, Seyed Hadi Razavi, Melika Shafiepour, Mohammad Afraei, M. Damghani Nouri
Abstract
Flavor generation in fermented foods is driven by the diverse metabolic activities of bacteria, yeasts, and molds. This review summarizes recent advances in understanding how these microorganisms convert carbohydrates, amino acids, and lipids into key flavor molecules through glycolysis, proteolysis, and lipolysis. Lactic acid bacteria, acetic acid bacteria, Saccharomyces and non-Saccharomyces yeasts, together with filamentous fungi such as Aspergillus and Penicillium, form the metabolic core of flavor biosynthesis across dairy, bakery, plant-based, and beverage fermentations. Stress-tolerance mechanisms—including resistance to acid, ethanol, salt, and temperature—are emphasized for their role in sustaining enzymatic activity and consistent volatile compound formation under industrial conditions. Integrating omics-driven insights and metabolic engineering enables the development of functional starter cultures tailored for enhanced ester, alcohol, and organic acid production while minimizing off-flavors. The review also highlights synergistic microbial interactions that shape aroma complexity and stability in multi-species fermentations. By bridging traditional fermentation knowledge with emerging biotechnological tools such as precision fermentation and strain engineering, this work provides a framework for designing natural, sustainable, and reproducible flavor systems for next-generation food innovation.