Sugar compounds

Sugars and carbohydrates are now commonly referred termed saccharides. The name derived from the Latin word saccharum, meaning ‘sugar’.

The compound sugars are made up of two or more molecules of monosaccharides and are further divided into two broad categories: oligosaccharides and polysaccharides.

Oligosaccharides and polysaccharides comprise two, several or many monomeric sugars covalently linked to each other by glycosidic bonds. Glycosidic bonds may have one of two orientations, termed alpha and beta.

Oligosaccharides, which are composed of two to nine, include sucrose (a disaccharide) and raffinose (a tri-saccharide).

The most common of the oligosaccharides is sucrose which contains two glycosidic-linked sugars, glucose and fructose. Some oligosaccharides serve storage functions a-in cells (e.g. sucrose, raffinose), whereas others accumulate as breakdown products from polysaccharides (e.g. maltose from starch, cellobiose from cellulose).

The polysaccharides are yield more than 1o molecules of monosaccharides on hydrolysis. They may be separated into three broad groups:
Homopolysaccharides (one kind of monosaccharide unit)
Heteropolysaccharides (two or more kinds of monosaccharides)
Nitrogen containing polysaccharides

Homopolysaccharides are composed of just one type of monosaccharide and heteropolysaccharides are built from more than one type. Typically, heteropolysaccharides molecule will be constructed from very few different monosaccharides.

The monosaccharides and disaccharides are sweet tasting and soluble in water. In contrast, the polysaccharides are colloidal, dispersible under certain conditions in water tasteless and vary greatly in digestibility.
Sugar compounds 

Oligosaccharide in foods

Complex carbohydrates consist of many monosaccharides bonded together in a variety of bonding patterns. 

Oligosaccharides yield 3 to 6 monosaccharide units on hydrolysis. These carbohydrates are attached to either the side chain oxygen atom of serine or threonine residues by O-glycosidic linkages or to the side chain nitrogen of asparagine residues by N-glycosidic linkages.

The commonly found oligosaccharides in foods are sucrose, maltose, lactose, raffinose and stachyose. 

Sucrose found throughout the plant world is most abundant in sugarcane, sugar beet and maple syrup. It is the familiar table sugar.

Foods high in oligosaccharides include onions, chicory, Jerusalem artichoke, asparagus globe artichoke, leek, garlic banana, and wheat.

Oligosaccharides also present in dried beans, soybeans, peas and lentils. Oligosaccharides have been dietary staples since antiquity and have received mush less attention than other carbohydrates, including simple sugars or dietary fiber.

In the body, oligosaccharides are components of cell membranes allowing cells to recognized and interact with one another.

Oligosaccharides play a key role in processes that take place in the surfaces of cells, particularly in cell-cell interactions and immune recognition.

Lately, interest in oligosaccharides has increased duetheir functional properties. These induce sweetening, ability, fat replacement, and enhancement of a ‘healthy’ gastrointestinal tract.
Oligosaccharide in foods