Research Progress Review on the Activation of Bioactive Substances by Targeted Fermentation of Rice Bran

Rice bran is a nutrient-rich agricultural by-product, and most of the bioactive compounds in it are bound and thus have poor bioavailability. Research has demonstrated that targeted microbial fermentation is a high-efficiency bioprocess for the degradation and modification of complex macromolecules to release phenolic compounds, flavonoids, dietary fibre derivatives and other new biologically active substances. Fermentation can be used to increase the antioxidant, anti-inflammatory and metabolically regulatory effects of rice bran more efficiently by changing its structure and increasing the content of active components compared with the conventional extraction method. Although some studies have investigated how to obtain suitable microbial strains and substrates, optimisation of the processing conditions for improving metabolic and functional performance has not been achieved; otherwise, other problems will still arise in the event of industrial-scale application, such as fluctuations in raw material supply, process instability, and high production costs. In the future, the integration of process analytical technology (PAT), artificial intelligence and microbial engineering will build a large-scale intelligent and controllable fermentation system. Therefore, the specific route of fermentation for valorising rice bran into high-value functional ingredients has been identified, and the scientific foundation for developing sustainable foods and nutraceuticals has been established.