Inulin is used for the determination of glomerular filtration rate (GFR). It is also used to measure body water volume.

Inulin is composed up of D-fructose. It can be catabolised by the enzyme inulinase. It does not show any colour when treated with iodine. Inulin does not have any dietary importance.

Occurrence Inulin is the main constituent of dahlias, onions, and garlics.

It is composed of repeating units of glucose joined by β(1 → 4) linkages (see Figure 2.15) Cellulose is insoluble in water, dilute acids, alkalis, and organic solvents. Cellulose is not easily digested by human system due to the lack of enzyme cellulose, which attacks the linkages in cellulose. Cellulose is as an important part of…

Cellulose is largely present in plant cells and is the most abundant carbohydrate present in nature. It forms the basis of vegetable fibres such as cotton and jute.

Dextrins give a red colour with iodine.

Dextrins are produced when starch is partially hydrolysed. This is carried out by acid or enzyme amylase. Dextrins produced from amylose have unbranched chains, whereas those produced from amylopectin have branched chains (refer Figure 2.14). Dextrins are soluble in water and get precipitated by alcohol. They have a sweet taste. Figure 2.14 Structure of Dextrin

Dextrins are present in all starch-producing plants. They are also present in honey and are the important constituents of various foods. They are used as adhesives and binders.

Glycogen shows a deep red colour with iodine.

Glycogen has a branched structure as well. It is a polymer consisting of D-glucose units. The glucose units in the linear structure are joined by α(1 → 4) glycosidic linkages and branching occurs via α(1 → 6) linkages (Figure 2.13). The branching point occurs at every eight to ten α-D-glucose units. This type of linkage…