Structures of salivary and pancreatic amylase hydrolysates from processed starches

Abstract

Digestion of starch in humans includes luminal and mucosal steps. Structures from the luminal phase of amylases hydrolysis can impact subsequent steps of digestion at the mucosa of the small intestine. However, structures of the starch digestion products along the gut from the mouth to the small intestines products that impact glucose homeostasis are not well understood. This submission focuses on the luminal step of starch digestion, i.e. impact of salivary and pancreatic amylases on the structure of hydrolysis products obtained from cooked starches from different botanical sources. Starch to water ratios of 1:0.7 (T0.7) or 1:2 (T2) were used to cook normal corn (NCS), wheat (NWS) and potato (NPS) starches. Comparatively, DMSO was used to disperse the starches to remove the effect of granular organisation. Cooked and dispersed starches were then subjected to salivary and pancreatic amylases hydrolysis for 20 min and 120 min. Extent of 20 min hydrolysis was lower at T0.7 compared to T2 and TD for all the starches. The molecular weight profiles of 20 min hydrolysates between the processing treatments were more different for NPS than for the other starches. Oligosaccharide composition of 120 min hydrolysates differed in amounts of DP 2, 3, 5, 6 and 7 between processing treatments and also between the starches. These differences, however, did not necessarily follow the intensity of cooking treatment. These differences in structures of hydrolysates, which are the substrate for mucosal hydrolysis in the small intestine, can potentially influence glucose homeostasis.