In vitro Colon Fermentation of Soluble Arabinoxylan Is Modified Through Milling and Extrusion.

Teresa Demuth,Christophe Lacroix,Laura Nyström,Lea Bircher,Annelies Geirnaert,Veronica Edwards

doi:10.3389/fnut.2021.707763

Abstract

Dietary fibers such as arabinoxylan (AX) are promising food constituents to prevent particular diet-related chronic diseases because of their prebiotic properties. Arabinoxylan fermentation by the gut microbiota depends on the structural architecture of AX, which can be modified during food processing and consequently affect its prebiotic potential, but it is little investigated. Therefore, the aim of this study was to evaluate the effects of naturally occurring and processing-induced structural alterations of the soluble AX of wheat bran and rye flour on the in vitro human colon fermentation. It was found that fermentation behavior is strongly linked to the AX fine structure and their processing-induced modifications. The short-chain fatty acid (SCFA) metabolism, acidification kinetics, bacterial growth, and bacterial composition revealed that wheat bran AX (WBAX) was fermented faster than rye flour AX. Increased levels of bound phenolic acids resulting from processing were identified as the inhibiting factor for AX fermentation kinetics. Bacterial genera promoted by AX varied between AX source and processing type, but also between microbiota. Extruded WBAX promoted butyrate production and growth of butyrate-producing Faecalibacterium in the butyrogenic microbiota while it did not enhance fermentation and inhibited the growth of Prevotella in the propiogenic microbiota. We anticipate that the findings of this study are a starting point for further investigation on the impact of processing-induced changes on the prebiotic potential of dietary fibers prior to human studies.

Highlights

The human gut microbiota represents a diverse ecosystem, which is populated by more than 1014 microorganisms harboring 100 times more genes than the human genome itself and, representing a tremendous metabolic potential [1]
This study was designed to investigate the effect of grain milling and extrusion on the in vitro colon microbiota fermentation of soluble AX isolated from wheat bran (WB) and rye flour (RF)
The naturally occurring and processing-induced structural changes of soluble AX were correlated with the fermentation behavior of two cultivated human colon microbiota (CM) to define a structure–function relation

Summary

Introduction

The human gut microbiota represents a diverse ecosystem, which is populated by more than 1014 microorganisms harboring 100 times more genes than the human genome itself and, representing a tremendous metabolic potential [1] This dynamic population has a significant contribution to human health by acting against pathogens, shaping the intestinal epithelium, regulating the host immune system, and degrading undigested food such as dietary fibers [2]. In vitro Colon Fermentation Soluble Arabinoxylan the microbes present in the colon [4, 5] This prebiotic activity leads to the various health benefits of dietary fibers, such as increasing the formation of short-chain fatty acids (SCFA) and causing fecal bulking. In addition to fruits and vegetables, cereals such as rye, barley, oat, and wheat are an important source of dietary fibers in the Western human diet

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