Non-Conventional Yeasts in Breadmaking: A Roadmap for Technological and Functional Selection Driving Future Bakery Biotechnology

While Saccharomyces cerevisiae remains the dominant species in industrial applications, the growing demand for bread with improved flavor and enhanced nutritional quality has stimulated interest in alternative yeast species. This review examines current knowledge on non-conventional yeasts (NCYs in bread fermentation and synthesizes recent advances into a structured roadmap for strain selection and technological application. The proposed roadmap integrates fermentative performance, carbohydrate utilization, tolerance to dough-related stresses, volatile compound production, functional enzymatic activities, and safety assessment. These selection parameters are also discussed according to bread formulation, enabling identification of NCY strains suitable for artisanal sourdoughs, industrial breads, high-sugar doughs, gluten-free formulations, and specialty bakery products. Several genera, including Torulaspora, Kluyveromyces, Wickerhamomyces, Pichia, and Hanseniaspora, have demonstrated metabolic versatility, enhancing aroma complexity and providing functional traits such as phytase and protease activities and FODMAP reduction, with potential benefits for mineral bioavailability and bread digestibility. However, safety assessment, including the absence of virulence factors and antifungal resistance, low biogenic amine production, and host compatibility, is essential for safe application in bakery systems. Overall, the proposed roadmap guides NCY development toward application-driven selection, supporting their rational use as tailored starters or adjuncts in bakery biotechnology.