Question

Identify the correct statement(s) related to grain polysaccharides among the following.

• A. Dextrin are a group of low molecular weight polysaccharides produced by dry hydrolysis of starch.
• B. Amylose is a linear polymer of D-glucose units joined by \(\alpha\) (1→6) glycosidic linkages.
• C. Amylopectin is a branched chain polymer of D-galactose monomer units.
• D. Retrogradation is a process of reassociation of amylose and formation of crystalline structure by gelatinized starch upon cooling.

Hint:

Amylose = linear, \(\alpha\)(1→4). Amylopectin = branched, \(\alpha\)(1→4) with \(\alpha\)(1→6). Retrogradation = starch molecules reordering on cooling.

Answer 1

The Correct Option is A, D

- (A) Correct: Dextrins are indeed short-chain polysaccharides formed during partial hydrolysis of starch (especially under dry heat).
- (B) Incorrect: Amylose is a linear polymer of D-glucose linked by \(\alpha\) (1→4) bonds, not (1→6).
- (C) Incorrect: Amylopectin is a branched polymer of glucose, not galactose. It has mainly \(\alpha\) (1→4) linkages with branch points at \(\alpha\) (1→6).
- (D) Correct: Retrogradation refers to the recrystallization/reassociation of amylose upon cooling of gelatinized starch.
\fbox{Therefore, the correct statements are (A) and (D).}