Question

Butter represents....................

• A. Oil in water emulsion
• B. Water in oil emulsion
• C. Oil in oil form
• D. Water in water form

Hint:

Phase inversion is the key physical mechanism in butter-making, turning an Oil-in-Water emulsion (cream) into a Water-in-Oil emulsion (butter).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
An emulsion is a colloidal dispersion of two immiscible liquids, where one liquid (the dispersed phase) is suspended as tiny droplets in another liquid (the continuous phase).
Emulsions are classified as oil-in-water (O/W) or water-in-oil (W/O) based on which phase is continuous.

Step 2: Detailed Explation:
Milk and cream are tural oil-in-water (O/W) emulsions.
In milk, fat globules (oil phase) are suspended throughout an aqueous phase containing water, lactose, minerals, and proteins.
When cream is subjected to mechanical churning during butter-making, the fat globule membranes are physically ruptured.
This mechanical action releases the liquid fat, which coalesces to form a continuous lipid matrix (the fat phase).
The water and water-soluble components of the cream are squeezed out as buttermilk, but some moisture remains trapped as tiny droplets throughout the fat matrix.
This phenomenon is known as phase inversion, where the O/W emulsion of cream is inverted into a water-in-oil (W/O) emulsion.
Therefore, butter is structurally defined as a water-in-oil (W/O) emulsion containing about 80% fat and 16-18% water.

Step 3: Fil Answer:
Butter is a classic example of a water-in-oil (W/O) emulsion produced via phase inversion.
Hence, the correct option is (B).