The distribution of endogenous polyphenols in black rice bran and their effects on starch digestion.
- 2026-04
- International journal of biological macromolecules 359
- Jing Lin
- Xinxia Zhang
- Ming Zhang
- Buyu Liu
- Dong Wang
- Ting Li
- Juan Li
- Li Wang
- PubMed: 41937020
- DOI: 10.1016/j.ijbiomac.2026.151799
Study Design
- Methods
- Non-targeted metabolomics, XRD, FTIR, rheological measurements, in vitro digestion
- Funding
- Unclear
This study investigated the distribution of endogenous polyphenols across different layers of black rice bran and their impact on starch structure and digestibility. Non-targeted metabolomics showed that the outer black rice bran layer was enriched in hydrophilic polyphenols (cyanidin-3-O-galactoside, tricin), whereas the inner layer accumulated hydrophobic flavonoids (nobiletin). XRD confirmed the formation of V-type crystalline structures with crystallinity reaching 26.5% - 36.5%. FTIR analysis showed enhanced short-range ordered structure and increased helical content. Rheological measurements revealed that black rice bran polyphenols (BRBPs) reinforced the gel network, with the crossover modulus increasing by up to 280.4%. Notably, BRBP1 from the outer layer exhibited the strongest anti-digestive effect, which was suggested to be attributed to its unique polyphenolic composition enabling dual hydrogen-bonding and hydrophobic interactions. In vitro digestion demonstrated that BRBPs significantly increased resistant starch content (from 19.5% to 24.6% - 32.6%) while reducing overall digestibility. These findings highlight the layer-specific functionality of black rice bran polyphenols and their potential as functional ingredients for modulating starch digestibility.