Question

Foods which form a zone of thinned material around a small agitator as mixing proceeds while the bulk of the food does not move are

• A. Pseudoplastic foods
• B. Viscoelastic foods
• C. Dilatant foods
• D. Thermal foods

Hint:

Pseudoplastic fluids thin under shear, forming a mobilized cavern around mixing impellers in stationary bulk fluids.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Non-Newtonian food systems exhibit shear-dependent apparent viscosity during mechanical agitation.

Step 2: Detailed Explanation:
Pseudoplastic (shear-thinning) fluids undergo structural breakdown and chain alignment under shear, reducing apparent viscosity with increasing shear rate.
During mixing with a localized impeller, high shear rates near the impeller cause significant localized thinning (a well-mixed low-viscosity cavern), while the unsheared bulk fluid at lower shear rates retains high viscosity and remains stationary.

Step 3: Final Answer:
Hence, such foods are pseudoplastic foods.