The whole grain-bacteria tango: How fermentation enhances the release and health benefits of phenolic compounds

Phenolic compounds in whole grains (WGs) are predominantly bound to dietary fibers, restricting their bioavailability and potential health benefits. Although growing studies are focusing on bacteria in fermented whole grains, how fermentation boosts phenolic compounds' release and health benefits is still not well understood. Here, we review the key microorganisms used in WG fermentation, along with the effects and potential mechanisms whereby microbial fermentation influences the release and transformation of phenolic compounds. Further, we summarize the latest progress in leveraging the health benefits of phenolic compounds in fermented WGs. Microbial fermentation significantly increases the content of free phenolic compounds by degrading cell wall matrices. Released phenolic compounds exhibit multifaceted health benefits. The application of omics technologies has further elucidated the microbial consortia and metabolic pathways involved. Understanding how microbial fermentation enhances the release of phenolic compounds in WGs is essential for their application in the food industry.