Effect of particle size on the release behavior and functional properties of wheat bran phenolic compounds during in vitro gastrointestinal digestion

Wheat bran is a rich source of phenolic compounds, and the health benefits of phenolic compounds depend on its bioaccessibility. The release behavior and functional properties of phenolic compounds in different particle size wheat bran during in vitro digestion were investigated. Coarse wheat bran (CWB, 1110.39 mu m) was milled by airflow impact mill to produce medium wheat bran (MWB, 235.68 mu m), fine wheat bran (FWB, 83.73 mu m) and superfine wheat bran (SWB, 19.16 mu m). The reduction in particle size increased the release of phenolic compounds, mainly ferulic acid, after digestion. The free p-coumaric acid content in SWB was nearly five times higher than that in CWB, MWB and FWB due to the complete destruction of aleurone cell walls. Moreover, SWB showed higher bioaccessible phenolic compounds content (65.51%) than CWB. The improved phenolic bioaccessibility increased the antioxidant capacities and carbohydrate-digestive enzymes inhibitory activities of SWB and significantly reduced its starch digestibility.

Automated summary

Reducing the particle size of wheat bran increased the release of phenolic compounds, especially in superfine wheat bran. The content of free p-coumaric acid in superfine wheat bran was higher, and it also had a higher content of bioaccessible phenolic compounds.