Question

Which of the following is referred to as "primrosing"?

• A. Pink colour discoloration of butter due to microbial growth
• B. Leakage of nitrogen gas from the headspace of whole milk powder package
• C. Red colour discoloration of liquid milk
• D. Surface desiccation of butter resulting in discoloration of butter

Hint:

Primrosing is a purely physical defect caused by surface drying.
Improper packaging that allows moisture evaporation is the primary cause of this deeper yellow surface discoloration.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Butter quality is assessed by its body, texture, flavor, and color.
Discoloration defects can arise from chemical oxidation, microbial contamination, or physical moisture loss from the surface.

Step 2: Detailed Explanation:
Let us examine the origin of the term "primrosing":
When butter is stored in improperly sealed packaging or exposed to dry air, water evaporates rapidly from the surface of the butter.
This process of surface drying is known as surface desiccation.
As water evaporates, the concentration of fat and beta-carotene pigments on the outer layer increases, and the salt crystals precipitate.
This results in the surface of the butter turning a much deeper, darker yellow color than the interior.
This physical color defect is referred to as primrosing (or primrose color defect).
Therefore, option 4 is the correct explanation.

Step 3: Final Answer:
Primrosing refers to the surface desiccation of butter resulting in its discoloration.