Question

Which one of the following types of cereal grains are generally described as waxy?

• A. High protein
• B. High fat
• C. High amylase
• D. High amylopectin

Hint:

Waxy starches contain nearly $100\%$ amylopectin ($0\text{--}2\%$ amylose); normal starches contain $20\text{--}30\%$ amylose and $70\text{--}80\%$ amylopectin.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Cereal starches are composed of two glucose polymers: linear amylose ($\alpha$-1,4 linkages) and highly branched amylopectin ($\alpha$-1,4 and $\alpha$-1,6 linkages).

Step 2: Detailed Explanation:
Cereal cultivars with the waxy gene mutation (e.g., waxy corn, waxy rice, waxy barley) produce endosperm starch composed almost entirely of branched amylopectin ($98\text{--}100\%$) and negligible amylose ($0\text{--}2\%$).
Waxy starches form clear, viscous pastes resistant to retrogradation and gelation.

Step 3: Final Answer:
Therefore, waxy cereal grains are characterized by high amylopectin content.