size reduction

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What is the primary function of a homogenizer in the preparation of emulsions?

To separate the fat globules from the liquid.
To cool the liquid rapidly before emulsification.
To add stabilizers to the emulsion.
To raise the pressure of the dispersion and create turbulence. (correct)

What occurs when the pressure in the homogenizer is released?

The dispersion turns into a solid mass.
The fat globules aggregate into larger particles.
The liquid becomes less viscous.
The energy stored as pressure is released, causing turbulence. (correct)

How does homogenization affect the stability of milk as an emulsion?

It reduces the size of fat globules, preventing separation. (correct)
It ensures that fat globules remain larger to promote cream formation.
It increases the size of fat globules for better separation.
It alters the composition of the milk to include more water.

What role does the spring in a homogenizer play during operation?

It controls the pressure and releases it rapidly. (B) Signup and view all the answers

What phenomenon causes cream to form when milk is not homogenized?

The gravitational separation of fat and water due to density differences. (C) Signup and view all the answers

What is the primary purpose of size reduction in food processing?

To improve the eating quality and suitability for further processing (D) Signup and view all the answers

Which type of operation is employed for reducing the size of solid materials?

Grinding and Cutting (D) Signup and view all the answers

What is one benefit of increasing the surface-area-to-volume ratio during size reduction?

It increases the rate of drying, heating, or cooling (A) Signup and view all the answers

Which of the following is NOT a type of grinder mentioned for size reduction?

Sifter (B) Signup and view all the answers

What effect can size reduction have on the shelf life of certain foods?

It can promote degradation due to enzyme release and oxidation (A) Signup and view all the answers

Which example demonstrates the process of grinding in food processing?

Milling grains to produce flour (B) Signup and view all the answers

What role do commonly used hammer mills play in size reduction?

Breaking particles using high-speed rotors (D) Signup and view all the answers

Which particle size characteristic can enhance ingredient mixing in food products?

Consistent particle sizes (B) Signup and view all the answers

What is the primary action of a hammer mill in breaking down brittle materials?

Impact from hammers against a stationary surface (B) Signup and view all the answers

Which type of materials require a cutting edge for effective processing in milling?

Fibrous materials (A) Signup and view all the answers

What is the main function of an emulsifier?

To stabilize suspensions of immiscible liquids (B) Signup and view all the answers

What happens to oil droplets when mixed with water without an emulsifier?

They remain as isolated droplets (A) Signup and view all the answers

What is an example of a common product that uses lecithin as an emulsifier?

Margarine (A) Signup and view all the answers

Which milling equipment component is responsible for material delivery?

Feed chute (B) Signup and view all the answers

What type of milling machine typically uses two to five rollers operating at different speeds?

Roller mill (A) Signup and view all the answers

In the context of emulsions, what does 'w/o' stand for?

Water in oil (C) Signup and view all the answers

What is the effect of a slow feed rate in milling?

Reduces the amount of smaller particles (C) Signup and view all the answers

What is a key feature of mechanical stirrers used in emulsification?

Generate both axial and radial flow (D) Signup and view all the answers

How does an emulsion typically stabilize over time?

By forming larger droplets that float (A) Signup and view all the answers

Which milling method is noted for its limited use in the food industry?

Ball mill (B) Signup and view all the answers

What should the ideally balanced rate of milling input and output ensure?

No particles remain in the milling chamber (B) Signup and view all the answers

What essential property is required for emulsions to maintain stability?

Presence of an emulsifier (A) Signup and view all the answers

Salad cream is an emulsion made from vegetable oil and water. In what ways is salad cream different from both oil and water ?

Salad cream is thick (viscous) and is not transparent (C) Signup and view all the answers

Why do we need to add an emulsifier to an emulsion like salad cream ?

To prevent the oil and water in the emulsion from separating (A) Signup and view all the answers

Size Reduction

A unit operation that decreases the average size of solid food pieces using grinding, compression, or impact forces.

Comminution

Another term for size reduction.