Question

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

• 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$\rightarrow$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:

Remember: Amylose = linear $\alpha$(1→4), Amylopectin = branched $\alpha$(1→6), Retrogradation = crystallization on cooling.

Answer 1

The Correct Option is A, D

Step 1: Check each statement.
- (A) True. Dextrins are indeed low molecular weight oligosaccharides obtained by hydrolysis of starch.
- (B) False. Amylose is a linear polymer of glucose linked by $\alpha$ (1$\rightarrow$4) linkages, not $\alpha$ (1$\rightarrow$6).
- (C) False. Amylopectin is branched but made of glucose units, not galactose. It has $\alpha$ (1$\rightarrow$4) linear chains and $\alpha$ (1$\rightarrow$6) branch points.
- (D) True. Retrogradation is the process of reassociation of amylose during cooling, leading to crystallization.
Final Answer: \[ \boxed{\text{(A) and (D)}} \]