Question

Average lactose content in whey powder is

• A. 20%
• B. 30%
• C. 15%
• D. 70%

Hint:

Whey powder consists primarily of lactose (around \(70\%\)), with whey proteins and minerals making up the remainder of the dry matter.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Whey is the liquid co-product obtained during the manufacture of cheese, casein, or paneer.
When whey is concentrated and spray-dried, the resulting whey powder retains the relative proportions of the solid constituents present in the original liquid whey.

Step 2: Detailed Explanation:
Liquid whey contains approximately \(6\%\) to \(5\%\) total solids, of which:
Lactose constitutes about \(70\%\) to \(75\%\) of the dry matter.
Whey proteins constitute about \(10\%\) to \(12\%\).
Minerals (ash) constitute about \(8\%\) to \(10\%\).
During the manufacture of sweet whey powder, moisture is removed while these solid ratios are preserved.
As a result, standard whey powder is highly concentrated in lactose, typically containing approximately \(70\%\) to \(72\%\) lactose by weight.
This makes whey powder a common source of lactose for the food and pharmaceutical industries.
The alternative options (\(15\%\), \(20\%\), and \(30\%\)) are incorrect because they underrepresent the lactose concentration of dried whey.

Step 3: Final Answer:
Therefore, the average lactose content in whey powder is approximately \(70\%\).