Simulated intestinal hydrolysis of native tapioca starch: understanding the effect of soluble fibre

Publication date: Available online 3 October 2015 Source:Bioactive Carbohydrates and Dietary Fibre Author(s): Hrvoje Fabek, H. Douglas Goff Soluble fibre has been shown to have a reducing effect on plasma glucose levels, which is of particular importance due to the rapidly increasing rates in type 2 diabetes. Researchers speculate that an increase in digesta viscosity is responsible for lowering glucose in the blood; however, the exact mechanism remains to be elucidated. In the present study we examined the effect that adding viscous soluble fibres would have on starch digestibility during simulated intestinal digestion. Tapioca starch was formulated with skim milk powder to act as a control. The treatments consisted of xanthan gum, guar gum, soluble flaxseed gum and soy soluble polysaccharide (SSPS) at constant viscosity. Subsequently, all solutions were exposed to a 3-stage in vitro digestion, mimicking the salivary, gastric, and small intestinal steps. Light scattering results showed that the particle size of starch granules decreased as digestion proceeded. Microscopy showed evidence of substantial degradation along the surface of the granules extracted from the control, flax and SSPS solutions upon completion of simulated small intestinal digestion. The progression of these changes was attenuated for granules that were extracted from the guar gum and xanthan gum solutions, which we believe is linked to their rheological behaviour as both solutions had greater vis...
Source: Bioactive Carbohydrates and Dietary Fibre - Category: Food Science Source Type: research