Prebiotic Effects and Fermentation Kinetics of Wheat Dextrin and Partially Hydrolyzed Guar Gum in an In Vitro Batch Fermentation System.

Joanne Slavin,Ashok Hospattankar,Kelly Swanson,Justin Carlson,Ping Deng

doi:10.3390/foods4030349

Abstract

Scientific research demonstrates that two indigenous gut bacteria, Lactobacillus and Bifidobacterium can contribute to human health. Although these bacteria can be consumed as probiotics, they can also be produced in the gut by bacteria, and are then called prebiotics. The primary objective of this in vitro study was to quantitatively analyze at the genus level how two dietary fibers, wheat dextrin (WD) and partially hydrolyzed guar gum (PHGG) changed the levels of these two gut bacteria at 12 and 24 h, via real time qualitative polymerase chain reaction (qPCR). Secondary objectives were changes in fecal pH, short chain fatty acids (SCFAs) and total gas volume produced. At 12 h WD was more bifidogenic (9.50 CFU log10/mL) than PHGG (9.30 CFU log10/mL) (p = 0.052), and also at 24 h WD (9.41 CFU log10/mL) compared with PHGG (9.27 CFU log10/mL) (p = 0.043). WD produced less total SCFAs at both 12 and 24 h than PHGG, and produced significantly lower amounts of gas at 12 and 24 h (p < 0.001). Both PHGG and WD also promoted growth of Lactobacilli when measured at 12 and 24 h compared with the 0 h analysis, indicating that both fibers are lactogenic. These results demonstrate the prebiotic effect of WD and PHGG. Based on fermentation kinetics, PHGG is more rapidly fermented than WD, and both fibers show prebiotic effects as early as 12 h.

Highlights

Dietary fiber is generally defined as nondigestible carbohydrates and lignin that are intrinsic and intact in plants, with functional fiber showing beneficial physiological effects in humans [1]
Each fiber produced a significant decrease in pH (Table 1), with Wheat dextrin (WD) decreasing more consistently over 24 h, while partially hydrolyzed guar gum (PHGG) decreased quickly between 4 and 8 h of fermentation, which is simultaneously reflected by the large increase in gas production at 8 h for PHGG
The human gut microflora is a diverse population, with many different genera of bacteria having very different influences on the host. Both Lactobacillus and Bifidobacterium are generally accepted as two beneficial genera of bacteria, and contribute to a myriad of health benefits to the host [4]

Summary

Introduction

Dietary fiber is generally defined as nondigestible carbohydrates and lignin that are intrinsic and intact in plants, with functional fiber showing beneficial physiological effects in humans [1]. U.S recommendations for dietary fiber, expressed as a Dietary Reference Intake, are 25 g/day for adult females and 38 g/day for adult males, the typical daily intake for U.S consumers is approximately 17 g/day [2,3]. Accepted health benefits associated with regular fiber consumption include maintaining a healthy digestive system, increased satiety, decreased caloric intake, and fermentation that results in beneficial changes in the gut microflora [4,5]. Supplementation of beneficial dietary fibers may be an effective way to help consumers get the recommended amount of dietary fiber, and its associated health benefits. WD is a soluble, fermentable fiber composed of a glucose polymer formed by the polymerization and hydrolysis of wheat starch that resists digestion in the small intestine due to its glucoside linkages [6]

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