Microbial fermentation of cereals: nutritional, techno-functional, and compositional transformations toward data-driven process optimization

Cereal fermentation represents a cornerstone of food bioprocessing that transforms staple grains into nutrient-dense, functionally enhanced ingredients. This review consolidates evidence on the ways in which microbial fermentation by bacteria, yeasts, and filamentous fungi alters the compositional, nutritional, and techno-functional properties of cereals. It summarizes molecular and structural transitions in carbohydrates, proteins, major cereal lipid fractions such as triacylglycerols, glycolipids, phospholipids, and free fatty acids, and dietary fiber, and links these changes to improved digestibility, bioactive compound release, and processing-relevant traits such as pasting behavior, swelling, and rheology. The influence of critical fermentation parameters such as substrate composition, pretreatment methods, inoculum selection, and process conditions is systematically assessed to elucidate their impact on product quality and stability. Machine learning can support the prediction of key quality attributes and optimization of fermentation conditions, but applications in cereal fermentation remain limited by data availability and model transferability. Therefore, this review primarily synthesizes current empirical findings while outlining how data-driven approaches could, in the future, support predictive modeling and process optimization. By integrating insights from microbiology, food chemistry, and process engineering, the review establishes a foundation for designing next-generation cereal fermentation that balances nutritional enhancement, functional performance, and industrial scalability.