Food Processing Unit Operations Multiple Choice Questions on “Basic Principles of Food Process Engineering”.
1. The basic operations done in the food process engineering are called as __________
a) unit operations
b) processing
c) process management
d) unit process
Answer: a
Clarification: The study of basic operations done in the food process engineering is called as unit operation. It involves physical or chemical transformations like separation, crystallization, filtration evaporation and other reactions. The unit process is defined as one or more grouped operations in manufacturing system.
2. Which of the following are the unit operations?
a) Distillation, evaporation, centrifugation
b) Distillation, membrane separation, sampling
c) Membrane separation, centrifugation, sampling
d) Evaporation, centrifugation, sampling
Answer: a
Clarification: The unit operations like distillation and membrane separation come under contact equilibrium process. The centrifugation, filtrations are under mechanical separation.
3. Unit operation is based on ______________
a) law of conservation of mass only
b) law of conservation of energy only
c) law of conservation of mass and energy
d) third law of thermodynamics only
Answer: c
Clarification: Law of conservation of mass applies to each component entering the process. For example, amount of milk entering through pasteurization inlet should be equal to amount of milk leaving the pasteurization outlet. Similarly, law of conservation of energy applies where total energy in the material entering the process plus energy added in the process must be equal to total energy leaving the process.
4. Are these statements about the contact equilibrium processes true?
Statement 1: Gas absorption, crystallization comes under the category of contact equilibrium processes.
Statement 2: Contact equilibrium processes does not depend on the concentration gradient.
a) True, False
b) True, True
c) False, True
d) False, False
Answer: a
Clarification: Gas absorption, crystallization are categorized under contact equilibrium processes. Contact equilibrium process is attained when the process reaches the equilibrium. Equilibrium is proportional to the concentration differences.
5. Which of the following is untrue?
a) Membrane separation follows the law of conservation of energy
b) Membranes are used for separating components in food on a molecular basis
c) Membrane separation cannot be used in ultrafiltration of blood proteins
d) Reverse osmosis is an important application in membrane separation
Answer: c
Clarification: Membrane separation follows the law of conservation of mass and energy. The membrane separation is used to separate gaseous and liquid streams. It is also used in ultrafiltration for concentrating solutions of large polymetric molecules like blood proteins and milk molecules.Reverse osmosis is a water treatment where sufficient pressure applied against the water to force it through a semi permeable membrane, the water molecules are separated from other constituents within the water.
6. Which of the following statements about unit operation performance are correct?
Statement 1: Performance of unit operation depends on material handling.
Statement 2: Optimization of time and movement of material from one unit operation to other is achieved by proper material handling techniques.
a) True, False
b) True, True
c) False, True
d) False, False
Answer: b
Clarification: Performance of unit operation depends on material handling. Optimization of time and movement of material from one unit operation to other is achieved by proper material handling techniques.
7. In an evaporator, the heat lost by heating water must be equal to the _____________
a) sum of heat gained by the product and heat lost from the evaporator to its surroundings
b) sum of heat lost from the evaporator to its surroundings in each step
c) heat gained by the product
d) overall heat lost from the evaporator