Question

•Discuss main types of hemicellulose present in softwood and hardwood.

•Explain the differences between amorphous and crystalline cellulose

Answer 1

Mannose is the most important hemicellulose present in softwood, which is present as ​O-acetyl- galactoglucomannan. The galactose present has a richer fraction of galactoglucomannan with a galactose to glucose to mannose ratio of approximately 1 : 1 : 3 .There are also present xylose, glucose, galactose and arabinose . On the other hand, xylose is the most important hemicellulose present in hardwood which occurs as O-acetyl-4-O-methylglucurono- xlan . There are also present mannose, glucose, galactose, with small amount of arabinose and rhamnose.

Crystalline cellulose is refined wood pulp used in food and pharma industry. It is purified, partially depolymerized cellulose which is prepared by treating alpha- cellulose. Amorphous cellulose is a structure consisting of several hundred to over ten thousand D-glucose residues joined by β(1→4) glycosidic linkages.