Structures of starch hydrolysates by luminal amylases: What is the impact of African starch sources on type 2 diabetes management?

The major source of energy to humans is starch. The digestion of starch in monogastric animals, including humans starts in the mouth. It may continue in the stomach. Pancreatic amylase further digests starch as the food moves through the small intestines. Mucosal enzymes finally convert starch structures into glucose for absorption. However, the digestion of starch has implications on health, especially with regards to type 2 diabetes. The rate of glucose release and/or delivery into the blood can be both beneficial or a cause of health concerns. The rate of glucose release depends on the starch hydrolysates that evolve during digestion. Yet, the molecular structures produced during the digestion of starch in the gut are not well understood. This paper presents results concerning the impact of oral digestion on starches from different botanical sources. Normal corn (NCS), wheat (NWS) and potato (NPS) starches were cooked at two starch to water ratios, 1:0.7 and 1:2. Cooked starches were then hydrolysed by salivary amylase to mimic digestion in the mouth. Using Gelpermeation chromatography, the extent of hydrolysis corresponded to moisture content used during cooking for all the starches. Debranching of the hydrolysates revealed structural differences in the extent of amylose hydrolysis and amount and profile of lower molecular weight fractions between different starches. These results show that the amount of water present during processing and botanical origin of starch affects structures of salivary amylase hydrolysates, which can possibly impact on glucose homeostasis.