Simulation of Human Small Intestinal Digestion of Starch Using an In Vitro System Based on a Dialysis Membrane Process

Abstract

This work deepens our understanding of starch digestion and the consequent absorption of hydrolytic products generated in the human small intestine. Gelatinized starch dispersions were digested with α-amylase in an in vitro intestinal digestion system (i-IDS) based on a dialysis membrane process. This study innovates with respect to the existing literature, because it considers the impact of simultaneous digestion and absorption processes occurring during the intestinal digestion of starchy foods and adopts phenomenological models that deal in a more realistic manner with the behavior found in the small intestine. Operating the i-IDS at different flow/dialysate flow ratios resulted in distinct generation and transfer curves of reducing sugars mass. This indicates that the operating conditions affected the mass transfer by diffusion and convection. However, the transfer process was also affected by membrane fouling, a dynamic phenomenon that occurred in the i-IDS. The experimental results were extrapolated to the human small intestine, where the times reached to transfer the hydrolytic products ranged between 30 and 64 min, according to the flow ratio used. We consider that the i-IDS is a versatile system that can be used for assessing and/or comparing digestion and absorption behaviors of different starch-based food matrices as found in the human small intestine, but the formation and interpretation of membrane fouling requires further studies for a better understanding at physiological level. In addition, further studies with the i-IDS are required if food matrices based on fat, proteins or more complex carbohydrates are of interest for testing. Moreover, a next improvement step of the i-IDS must include the simulation of some physiological events (e.g., electrolytes addition, enzyme activities, bile, dilution and pH) occurring in the human small intestine, in order to improve the comparison with in vivo data.

Prospecting in silico antibacterial activity of a peptide from trypsin inhibitor isolated from tamarind seed

“…On the other hand, this study used a universally recognised protocol that simulates in vitro digestion based on human digestion parameters and uses endogenous human enzymes 28 . Furthermore, in vivo models in humans, with proper physiological parameters, are the ideal way to simulate food digestion, but ethically and financially, it is not always feasible 60 .…”

A Critical Review on In Vitro and Ex Vivo Models of the Intestinal Epithelium of Humans and Monogastric Animals

“…In the reverse dialysis method, the dialysis bag is filled with intestinal fluid, and the bag is placed in a container with the compound of interest dissolved [92]. One critical factor in this technique is the pore size of the membrane, which is usually under 20 kDa [93][94][95]. From a different perspective, two approaches can be found in the literature regarding this process.…”

“…On the other hand, it is also possible to find some standardized and complex systems for BC prediction for both drugs and foods, such as the TNO Gastrointestinal Model (TIM) or Engineered Stomach and Small Intestine (ESIN), which include dialysis membranes as a last digestion step for simulating intestinal absorption, namely passive absorption [12,97]. For example, González et al, 2020 [95] reported an improved dialysis system based on a continuous flow of fluid at a controlled temperature for a more realistic dynamic small intestine simulation. In 2007, another dialysis system arose: the AMI system.…”

“…Study on starch digestion and the consequent absorption of hydrolytic products generated in the human small intestine, using an in vitro intestinal digestion system (i-IDS) [95] Phenolics, flavonoids, rutin, β-carotene and lutein in six edible greens Cellulose membrane (12,000 Da)…”

New understanding from intestinal absorption model: How physiological features influence mass transfer and absorption

“…A limited number of in vitro researches can be identified to mimic the absorption process by using a semipermeable membrane that allows the passage of digested products (i.e., small molecules) and blocks undigested substrates. [8][9][10] For in vitro systems, it is difficult to implement complex geometrical features of a real small intestine, such as circular folds and villi, which affect the flow pattern and thus the mass transfer. 11,12 Even if some research groups used excised animal intestinal tissues 13 or cultured epithelial cell monolayer, 14 various movements of the intestinal walls, for example, segmentation and peristalsis, can hardly be implemented in those experiments.…”