Polysaccharides are natural macromolecules present in almost all living organisms, and they function either as a source of energy or as structural units in the morphology of the living materials.
Most of the carbohydrates in nature occur as polysaccharides. Polysaccharides can be defined as carbohydrates that contain many monosaccharides. Poly means ‘many’ and in reality, most polysaccharides contain many monosaccharides up to hundreds or even thousands of monosaccharides.
They are formed by a few types of hexoses, hexose derivatives (uronic acids and sulphate esters) and pentoses.
Polysaccharides occur in many food products and even then they often retain their natural role as skeletal substances (fruit and vegetables) or assimilative nutritive substances (cereals, potatoes, legumes).
The most common digestible polysaccharide in plants is starch, a polymer of glucose. No polysaccharide other than starch is digested in the human small intestine.
Starch is present primarily in the cells of grains, fruits and tubers in the form of granules that, under microscopes examinations, appear to be typical for each starch.
Cellulose, hemicellulose, pentosans and pectic substances provide structural material. Chitin and muco-polysaccharides (containing amino sugars), serve this purpose in animals. Structural polysaccharides provide bulk in the diet and aid excretion.
The majority of polysaccharose used in the food industry are derived from plant materials such as seaweeds, seeds and tree exudates.
Polysaccharides in food
