Agricultural/Bioengineering Agricultural/Bioengineering: Food Engineering 2

Question 1

Which heat transfer mechanism is primarily responsible for cooking food in a microwave oven?

Accepted Answer

Dielectric heating

Answer

Convection

Answer

Conduction

Answer

Radiation

Question 2

The 'z-value' in thermal processing refers to:

Accepted Answer

The temperature increase needed to reduce D-value to 1/10th

Answer

The temperature increase needed to reduce D-value by 90%

Answer

The log reduction in microbial count at a given temperature

Answer

The pH at which microbial death rate is maximized

Question 3

Which of the following is NOT a colligative property exploited in food preservation?

Accepted Answer

Surface tension reduction

Answer

Osmotic pressure

Answer

Boiling point elevation

Answer

Freezing point depression

Question 4

In extrusion processing of food, the 'specific mechanical energy' (SME) input affects:

Accepted Answer

Starch gelatinization, protein denaturation, and product expansion

Answer

Only the color of the extrudate

Answer

Only product moisture content

Answer

Only extruder throughput rate

Question 5

What is the primary purpose of blanching vegetables before freezing?

Accepted Answer

To inactivate enzymes that cause quality deterioration

Answer

To add color to the vegetables

Answer

To reduce microbial load to zero

Answer

To increase the freezing rate

Question 6

The Maillard reaction in food processing requires which two types of reactants?

Accepted Answer

Reducing sugars and amino acids

Answer

Oxidized lipids and free water

Answer

Ascorbic acid and metal ions

Answer

Polyphenols and oxygen

Question 7

In food rheology, a fluid whose viscosity increases with increasing shear rate is classified as:

Accepted Answer

Dilatant

Answer

Pseudoplastic

Answer

Newtonian

Answer

Bingham plastic