Q. 13.74 - An Introduction to General, Organic, and Biological Chemistry

Question

Why are lactose and maltose reducing sugars, but sucrose is not? (13.6)

Step-by-Step Solution

Answer

• Lactose is a sugar present in milk and milk products such as cheese and ice cream. 
• Lactose malabsorption is the source of digestive discomfort in lactose intolerance. 

Step 1 :Introduction

• Lactose is a sugar present in milk and milk products such as cheese and ice cream. 
• Lactose malabsorption is the source of digestive discomfort in lactose intolerance. 
• Maltose, often known as malt, is a disaccharide that consists of two alpha D glucose units. An alpha 1,4 glycosidic bond connects the two units of glucose. 
• The enzymes maltase and isomaltase break down maltose molecules into two glucose molecules in the human small intestine mucosa, which are then absorbed by the body. 
• After cellulose, starch is the most abundant carbohydrate in plant cells.

Step 2: Check whether lactose and maltose reducing sugars, but sucrose is not

• Lactose and maltose have free $-\mathrm{OH}$ groups on the glucose or fructose molecules that's why they are reducing sugar while sucrose has no free -OH groups