In vitro digestion of pectin- and mango-enriched diets using a dynamic rat stomach-duodenum model

Abstract

In this study we investigated the in vitro digestive behaviors of starch-based diets enriched with soluble fiber (pectin) and fruit powder (mango) varying with dry matter contents using a dynamic rat stomach and duodenum model. The changes in pH with respect to digestion time, gastric emptying, starch and protein hydrolysis as well as rheological and microstructural properties of the gastric and duodenal digesta were investigated. The effects of porcine gastric mucin on digestion were studied as well. The results showed that gastric digestion and emptying rate were decreased with increasing dry matter content of the diets. Both the dynamic and steady shear viscosity of the duodenal digesta was lower than the gastric digesta due to hydrolysis of starch and protein as well as dilution by added digestive juice. With the same dry matter content (20.35%), the rates of gastric emptying as well as starch and protein hydrolysis were higher in the control and mango diets compared to the pectin diet, illustrating the complex relationships among rheology, soluble dietary fiber and digestion. The addition of gastric mucin could delay the rates of gastric digestion and emptying by increasing digesta viscosity. The study emulates the complexity of heterogeneous diets during simulated gastric and duodenal digestion and suggests that the viscosity generated by either addition of mucin on the diet or naturally exerted by e.g. pectin could be the rate limiting factor for both gastric emptying and hydrolysis of starch and proteins.

A Soft‐Elastic Reactor Inspired by the Animal Upper Digestion Tract

“…In this case, it is a good entry point for getting involved in the bio‐inspired chemical engineering, working on the understanding of the physiology of animal and human digestion. We have constructed uniquely the near‐real in vitro stomach systems for rats and humans . An interesting intestinal bench‐scale silicone tubular reactor was constructed and investigated for residence time distribution and, most recently, a process for hydrolysis of the very viscous solution of starch was demonstrated with the intestinal reactor .…”

Effect of food structure on macronutrients digestion and fermentation kinetics

“…It has been previously reported that the DIVRSD model captures the main mechanical and biochemical events occurring in the rat stomach and duodenum (Wu et al 2017;Wu et al 2014). The rate and extent of food digestion in the DIVRSD model was found to be statistically similar to that found for rats in vivo (Wu et al 2014).…”

“…However, these models do not consider the different mixing patterns, dynamic fluid behaviour or mechanical forces encountered by food chyme when it is passed through the gastro-intestinal tract (Kong & Singh 2010). These limitations are addressed by dynamic models, which simulate physico-chemical and physiological conditions as well as representing the geometrical and morphological details of real GI tracts (Chen, Jayemanne & Chen 2013;Moreno 2007;Wu et al 2017). Some of the successful dynamic food digestion models are TNO's gastrointestinal model (TIM) (Blanquet et al 2004 in vivo studies and could be successfully used to study the integrity of food under simulated physiological and mechanical conditions (Wu et al 2017).…”

“…A constant enzyme to substrate ratio was kept during the whole digestion process. The DIVRSD model system was maintained at 37 °C with compression-rolling extrusion creating 3 contractions per minute in the stomach while a rolling extrusion produced 36 contractions per minute in the duodenum chamber equivalent to a force of ca 3.5 N (Wu et al 2017) in each chamber. The digested aliquot from the duodenal phase was collected in 15 mL falcon tubes at defined intervals up to 120 min (0, 15, 30, 60, 90 and 120 min) and placed into a boiling water bath for 5 min to stop the enzymatic activity.…”

“…In vitro Rat Stomach Duodenum (DIVRSD) model, that mimics the mechanical and biochemical conditions occurring in the rat stomach and duodenum (Wu et al 2017) is used to study the physical integrity as well as the enzymic hydrolysis of entrapped nutrients using isolated legume cells (Dhital et al 2016) that are devoid of released starch/proteins and broken cells. As the integrity of legume cells is the limiting factor affecting the rate and extent of starch/protein hydrolysis (Dhital et al 2016), a dynamic model such as the DIVRSD is appropriate.…”