The physiological functions of dietary fiber and its role in health promotion and risk reduction of some chronic diseases has been well documented. In the present investigation, the effect of three dietary fiber sources, oats (OA), barley (BA) and psyllium husk (PH) on glucose adsorption, diffusion and starch hydrolysis were studied using in vitro techniques by simulating gastrointestinal conditions and compared with the commercial dietary fiber sources wheat bran (WB), acarbose (ACB) and guar gum (GG). The glucose binding capacity of all the samples was higher than WB and ACB at 5 mM concentration. In all the samples, the diffusion of glucose was directly proportional to the time and diffusion rate was significantly lower (p ≤ 0.01) in the system containing various samples compared to control. Glucose dialysis retardation index (GDRI) was 100 for OA, BA and PH at 60 min, at 120 min the maximal GDRI was in PH. Whereas; WB and ACB exhibited maximal GDRI at 180 and 240 min. All of these mechanisms might create a concerted function in lowering the rate of glucose absorption and as a result, decrease the postprandial hyperglycemia.
Keywords: Amylolysis kinetics; GDRI; Glucose adsorption; Glucose diffusion; Hypoglycemic effect.