The word of starch comes from Middle English word, strechen meaning ‘to stiffen’. Starch can exist in two forms, amylose and amylopectin, both of which are polymers of D-glucose.
The amylase molecule is a linear, unbranched structure in which the glucose residues are attached solely through a-1,4 glycosidic bonds. Amylopectin, on the a other hand, is a branched-chain polymer, the branch points occurring through a-1,6 glycosidic bonds.
Starch provides humans with energy 4 kcal per gram and is hydrolyzed to glucose, supplying the glucoses that is necessary for brain and central nervous system functioning.
To digest starches, humans have specialized digestive enzymes called amylases.
These enzymes breakdown starches into glucose, which is either used immediately as an energy source or stored in the liver and to be released when needed.
Food starch