Whole Tibetan Hull‐Less Barley Exhibit Stronger Effect on Promoting Growth of Genus Bifidobacterium than Refined Barley In Vitro

Abstract The gut microbiota has recently become a new route for research at the intersection of diet and human health. The aim of this study was to investigate whether whole Tibetan hull‐less barley (WHB) and refined Tibetan hull‐less barley (RHB) caused differentiation of the fecal microbiota in vitro . The microbiota‐accessible ingredients in the 2 barley samples were studied using an in vitro enzymatic digestion procedure. After in vitro digestion, insoluble dietary fiber, phenolic compounds, proteins, and β‐glucans were 93.2%, 103.4%. 18.8%, and 10.2% higher provided by WHB flour as compared with RHB flour based on the same mass amount. However, due to the significantly higher content of insoluble dietary fiber, WHB digesta had lower percentage contents of fast fermentable substrates including dietary fiber and starch as compared with RHB digesta. The results of Next‐generation sequencing of the bacterial 16SrRNA gene showed that both WHB and RHB fermentation had significantly promoted the growth of Bifidobacterium and inhibited the growth of pathogenic bacteria such as Dorea , Escherichia , Oscillopira , and Ruminococcus . Moreover, in response to WHB fermentation, the relative abundance of Bifidobacterium increased by 78.5% and 92.8% as compared with RHB and fructo‐oligosaccharides (FOs). Both WHB and RHB are good sources of fermentable dietary fiber with the ability to yield high concentration of short chain fatty acids (SCFAs) as compared to FOs. However, the higher fraction of soluble fiber in RHB digesta increase higher amounts of SCFA compared with WHB digesta. Our findings shed light on the complex interactions of whole cereals with gut microbiota and the possible impact on host health. Practical Application Until now, only few reports have regarded the impact of in vitro digestion in components of whole grain with complex food matrix. Moreover, our findings shed light on the complex interactions of whole cereals with gut microbiota and the possible impact on host health.