Starch is a polysaccharide made up of glucose until linked together to form long chains. It is one of the most abundant storage polysaccharides in plants and at the same time the most important energy source in human and animal nutrition.
After cooking starch is highly digestible by human beings, raw starch often resists digestion.
The number of glucose molecules joined in a single starch molecule varies from five hundreds to several hundred thousand, depending on the type of starch.
Starch is the storage form of energy for plants. However to use it for humans, either as structuring compound in foods or for technical application, as it does not provide all the desired properties.
Two types of starch molecules exist-amylose and amylopectin. Amylose averages 20 to 30 percent of the total amount of starch in most native starches.
Amylopectin is a branched chain polymers. Amylose consists of linear chain polymers.
Different plants have different relative amounts of amylose and amylopectin. These different proportions of the two types of starch within the starch grains of the pant five each starch its characteristics properties in cooking and gel formation.
The crystalline structure of the granule is attributed to the presence of the amylopectin molecules, which arrange themselves in concentric rings. The rings consist of soft amorphous and hard semi crystalline shells.
In food starches are used to increase viscosity or to form gels. Because starch is insoluble in water, a mixture of starch with forms a suspension.
Thermal processing can change the physiochemical properties of starch, therefore it can affect s the texture of food products, characterization of aqueous starch suspension behavior and its interaction with other food additives.
Starch