In Vitro and In Vivo Digestibility of Native Maize Starch Granules Varying in Amylose Contents

Abstract

Digestibility of maize starch granules with different amylose content (AL-0, 22, 54, 68, 80, or 90) was investigated. Measurement of the in vivo resistant starch (RS) content of the starches was performed using surgically prepared ileorectostomized rats. The rats were fed a purified diet containing one of the starches at 652.5 g/kg diet. The in vivo RS content was determined based on the fecal starch excretion. The dietary fiber (DF) value increased as a function of the amylose content in the starch and showed a positive linear correlation with the gelatinization temperature of the granules. In contrast, the in vitro RS content was likely to depend on both the surface area and amylose contents of the starch granules. The maximum in vitro RS content was obtained with AL-68 (54.4). In vivo RS content showed a significant correlation with the amount of in vitro RS but not in respect to the DF detected. The in vivo RS content of AL-68 (43.4) was higher than that found in AL-90 (37.8). A profound gap was observed for AL-54 between the amount of DF (6.4) and RS (in vitro = 46.6 and in vivo = 40.9) present. The results suggest that both in vitro and in vivo digestibility of maize starch is affected by the amylose content and surface area of the granules. The current evaluation suggests that the physiological occurrence of RS from maize starch might be predictable by reference to the in vitro RS value.

Oral intake of slowly digestible α-glucan, isomaltodextrin, stimulates glucagon-like peptide-1 secretion in the small intestine of rats

“…The surgical procedure was carried out as per the method of Lambert (21,22) with some modifications, as follows. As described by Morita et al (23) , to shorten the recovery period, the caecum and the colon were not dissected; instead, the ileocaecal valve was ligated. Next, the colonic terminal was anatomised via a stoma in the abdominal wall to allow caecal and colonic contents to be excreted as natural as possible.…”

Effect of native starch granule size on susceptibility to amylase hydrolysis

“…The composition and structure of native starch granules regulate hydrolysis by amylase . High amylose maize starches are, for example, much more resistant to hydrolysis than normal or waxy varieties . Crystallinity is generally considered to restrict hydrolysis although annealed starches – with ‘perfected’ crystallinity – are usually hydrolysed more rapidly than untreated starches.…”

Starch determination, amylose content and susceptibility to in vitro amylolysis in flours from the roots of 25 cassava varieties

“…Amylose is characterized by an essentially linear, packed and also more compact structure than amylopectin 28. Hence, the α‐amylolysis rate of native starches generally decreases with the amylose content 36. According to the statistical analysis of present data, an inverse correlation ( r = − 0.59, P < 0.05) between AC and AI could be established for the flours from 18 of the cultivars (Table 1).…”