Products of lactose hydrolysis in carbohydrate chemistry When the disaccharide lactose is hydrolyzed by lactase (β-galactosidase), which monosaccharides are released?

Introduction / Context:
Lactose is the principal sugar in mammalian milk. Its digestion requires specific enzymatic cleavage of the glycosidic bond. Understanding the exact monosaccharide products is fundamental in nutrition, biochemistry, and clinical contexts like lactose intolerance.

Given Data / Assumptions:

• Lactose is composed of glucose and galactose.
• The glycosidic linkage is β(1→4) between galactose and glucose.
• Lactase (intestinal) or β-galactosidase (microbial) catalyzes hydrolysis.

Concept / Approach:

Hydrolysis adds water across the glycosidic bond, releasing the two constituent monosaccharides. Unlike sucrose, which yields glucose and fructose, lactose yields glucose and galactose specifically, explaining differences in sweetness and metabolism.

Step-by-Step Solution:

Verification / Alternative check:

Enzymatic assays and dietary carbohydrate chemistry consistently show glucose and galactose as lactose products.

Why Other Options Are Wrong:

Options A and D incorrectly include fructose. Option C describes sucrose hydrolysis. Option E lists ribose, which is a pentose in nucleotides, not in lactose.

Common Pitfalls:

Confusing common disaccharides (lactose vs sucrose) or thinking all disaccharides yield glucose + fructose.

Final Answer:

Galactose and glucose