Category: Food Processing Unit Operations Objective Questions

250+ TOP MCQs on Distillation Basics and Answers

Food Processing Unit Operations Multiple Choice Questions on “Distillation Basics”.

1. What are the two processes in distillation?
a) Distilling and freezing
b) Distilling and condensation reflux
c) Freezing and condensation reflux
d) Only condensation reflux
Answer: b
Clarification: Distillation is the process where it consists of two processes of distilling and condensation reflux. It is usually carried out in distillation column, the gas-liquid two-phase flow through the countercurrent contact.

2. What are the basic methods of distillation?
a) Fractional distillation and simple distillation
b) Fractional distillation, destructive distillation and simple distillation
c) Steam distillation, simple distillation and gas distillation
d) Steam distillation and destructive distillation
Answer: b
Clarification: Simple distillation, fractional distillation where different volatile fractions are collected as during the process and destructive distillation where a material is heated so that it decomposes into compounds for collection.

3. Who discovered distillation?
a) Jabir ibn Hayyan
b) Guldberg and Waage
c) Charles Chamberland
d) Clarence Birdseye
Answer: a
Clarification: Jabir ibn Hayyan discovered distillation. Guldberg and Waage recognized that chemical equilibrium. Clarence Birdseye developed freezing process. Charles Chamberland developed steam pressure sterilizer.

4. What apparatus is used in distillation?
a) Distillation flask, condenser, collection vessel
b) Distillation flask, condenser
c) Condenser, collection vessel
d) Distillation flask, column
Answer: a
Clarification: Distillation apparatus consists of three units, they are distillation flask which is used for heating the mixture and volatizing the components. Next is condenser for cooling the vapors back to liquid state and lastly collection vessel for collecting the end product.

5. Where is double distillation method used?
a) To prepare distilled water for laboratory purposes
b) To produce distilled water for commercial purposes
c) To produce wine for commercial purposes
d) To produce coffee for commercial purposes
Answer: a
Clarification: Double distillation consists of flak with heating elements. It is used for carrying out the reactions under stirred conditions besides furnishing for reflux distillation. It is used to prepare distilled water for laboratory research.

6. What is the distillate in distillation?
a) Vapor collected from the mixture
b) Liquid present in the distillation column
c) Vapor introduced during distillation process
d) Liquid introduced during distillation process
Answer: a
Clarification: A distillate in the distillation process is defined as the vapor in a distillation column that is collected and condensed into a liquid and collected in the collecting flask.

7. Why is steel wool used in fractional distillation?
a) Increases the surface area
b) Improves the separation between the liquids
c) Increases the surface area and improves the separation between the liquids
d) Increases the surface area and the quality of the distillate
Answer: c
Clarification: Fractionating column is filled with a packing material like glass, steel wool and plastic beads. It increases the surface area and improves the separation between the liquids being distilled.

8. Does vacuum distillation higher boiling point?
a) True
b) False
Answer: b
Clarification: The vacuum distillation happens at a considerable reduced pressure, therefore reduces the boiling point of a substance.

9. Which of the following is produced by triple distillation method?
a) Coffee
b) Beer
c) Whisky
d) Wine
Answer: c
Clarification: Triple distillation is defined as the process where smooth whiskies are manufactured. Through refining the spirit over three distillations, it concentrates a particular fraction of flavorful compounds and aromatic substance that results in a very smoother taste.

10. Why porcelain pieces are used in distillation?
a) To have uniform boiling
b) To hasten the process
c) To add weight for the substance
d) To absorb excess heat from the flask
Answer: a
Clarification: The porcelain pieces or the glass beads are put in the distillation flask in the beginning to have uniform boiling throughout the solution and avoid bumping of the solution due to uneven heating.

250+ TOP MCQs on Drying Equipments and Answers

Food Processing Unit Operations Multiple Choice Questions on “Drying Equipments”.

1. Which of the following dryer is used for pureed raw ingredients that are dried at relatively low temperatures over rotating?
a) Fluidized bed dryer
b) Drum dryer
c) Cabinet tray dryer
d) Pneumatic dryer
Answer: b
Clarification: In the drum dryer, the pureed raw ingredients are dried at low temperatures over rotating. The additional advantage of this drier is that product is milled to produce powder or flakes form.

2. Which of the following dryer is used to produce powder from the solution?
a) Spray dryer
b) Cabinet tray dryer
c) Pneumatic dryer
d) Fluidized bed dryer
Answer: a
Clarification: Spray dyer is used to produce powder from the solution. It dries the solution stream and separates the solute and evaporates the solvent and forms vapor. The solid particles are collected in a cyclone or drum.

3. Who invented spray dryer?
a) Samuel Percy
b) Fritz Winkler
c) John A
d) Jacques-Arsened’Arsonva
Answer: a
Clarification: Samuel Percy invented spray dryer. Fritz Winkler invented fluidized bed dryer. John A invented drum dryer. Jacques-Arsened’Arsonva invented freeze dryer.

4. What is the alternative name for batch-in-bin dryer?
a) Flat bed dryer
b) Cabinet tray dryer
c) Pneumatic dryer
d) Fluidized bed dryer
Answer: a
Clarification: Batch-in-bin dryer is also known as flat bed dyer. Its capacity is of 1-3 tons per day with 6-12 hours of drying times. The batch-in-bin dryer is easy to construct and is inexpensive and simple to operate and require unskilled labor.

5. What is full form of LSU dryer?
a) Louisiana State University dryer
b) Low simple universal dryer
c) Low and slow unit dryer
d) Level steady unit dryer
Answer: a
Clarification: In Louisiana State University dryer, the drying section contains vertical compartment across which rows of air channels are fitted. Alternate rows are closedwhere the moving stream of grain from the top descends thus providing considerable mixing.

6. Which of the following statements about LSU dryer are correct?
Statement 1: LSU dryer is mainly used to dry the grains.
Statement 2: LSU is a continuous flow mixing type of dryer.
a) True, False
b) True, True
c) False, True
d) False, False
Answer: b
Clarification: LSU is a continuous flow mixing type of dryer. LSU dryer is mainly used to dry the grains. It is popular in India and USA. The capital investment is high. The recommended air flow rate is 60-70m3/ min/ ton.

7. What does Fritz Winkler invented?
a) Fluidized bed dryer
b) Drum dryer
c) Spray dryer
d) Freeze dryer
Answer: a
Clarification:Samuel Percy invented spray dryer. Fritz Winkler invented fluidized bed dryer. John A invented drum dryer. Jacques-Arsened’Arsonva invented freeze dryer.

8. Which dryer is used to dry the material almost instantaneously in a turbulent stream of hot air?
a) Fluidized bed dryer
b) Drum dryer
c) Cabinet tray dryer
d) Pneumatic dryer
Answer: d
Clarification: In pneumatic dryer, the material is dried almost instantaneously in a turbulent stream of hot air. This can also acts as conveyor system. It is applicable to powdered, granular, and flaky materials.

9. Which of the following dryer is the convectional drying equipment with enclosed insulated chambers?
a) Fluidized bed dryer
b) Drum dryer
c) Cabinet tray dryer
d) Pneumatic dryer
Answer: c
Clarification: Cabinet tray dryer is conventional drying equipment with enclosed insulated chambers. The trays are placed on top of each other in a trolley. The mode of heat transfer is forced convention.

10. What type of dryer is used for the drying of substances which are hygroscopic?
a) Fluidized bed dryer
b) Drum dryer
c) Cabinet tray dryer
d) Vacuum dryer
Answer: d
Clarification: Vacuum Tray dryer is the most commonly used batch dryer. Vacuum Tray Dryer is used for drying of hygroscopic substances and heat sensitive materials, which are dried to very low residual moisture content level.

250+ TOP MCQs on Heat Radiation and Answers

Food Processing Unit Operations Multiple Choice Questions on “Heat Radiation”.

1. Which is the fastest mode of heat transfer?
a) Conduction
b) Convection
c) Radiation
d) Both conduction and convection
Answer: c
Clarification: The fastest mode of heat transfer is radiation as it travels at the speed of light. Conduction is the slowest mode of heat transfer because it takes place from particle to particle.

2. Which law governs the thermal radiation?
a) Fourier’s law
b) Pascal law
c) Newton law
d) Stefan-Boltzmann Law
Answer: d
Clarification: Stefan-Boltzmann Lawgoverns the thermal radiation. It statesthat the total radiant heat power emitted from a surface is proportional to the fourth power of its absolute temperature.

3. Are these statements about the thermal radiation true?
Statement 1: It follows Stefan-Boltzmann Law.
Statement 2: It also depends on Wien’s Displacement Law.
a) True, False
b) True, True
c) False, True
d) False, False
Answer: b
Clarification: Thermal radiation follows Planks law and also Wien’s Displacement Law. Stefan-Boltzmann Law states that the total radiant heat power emitted from a surface is proportional to the fourth power of its absolute temperature.Wien’s Displacement Law states that a hotter object will emit radiation with a shorter wavelength.

4. The emissivity of radiation is between__________
a) 0 and 1
b) 0 and 10
c) 0 and 15
d) 0 and 11
Answer: a
Clarification: The emissivity of radiation is between0 and 1. It can be defined as the ratio of the thermal radiation from the surface to the radiation from an ideal black surface at a constant temperature. This is derived under Stefan–Boltzmann law.

5. In thermal radiation, thermal energy is converted to ___________________
a) kinetic energy
b) potential energy
c) electromagnetic energy
d) thermal energy
Answer: c
Clarification: In thermal radiation, thermal energy is converted to electromagnetic energy. This is achieved by the thermal motion of the particles in the substance. All the substance with a temperature greater than absolute zero emits the thermal radiation. The motion of the particle results in acceleration of charge and dipole oscillation which produces electromagnetic energy.

6. What is the wavelength of thermal radiation?
a) 0.1 μm to 1000 μm.
b) 1 μm to 100 μm.
c) 0.01 μm to 100 μm.
d) 0.1 μm to 100 μm.
Answer: d
Clarification: The thermal radiation is the electromagnetic radiation emitted from all the substance that is at non-zero temperature in the wavelength ranging from 0.1 μm to 100 μm. This includes part of ultraviolet rays, all of the visible and infrared rays.

7. Can a good insulator prevent radiation?
a) True
b) False
Answer: a
Clarification: Hot objects radiate infra-red electromagnetic waves, so therefore insulation against heat transfer by radiation is done by using reflective materials. The thermos bottle has a shiny material along with a lining to prevent heat conduction. This shiny material reflects heat from the radiation from inside as well as outside the bottle.

8. What are factors of thermal radiation?
a) Time
b) Temperature
c) Volume
d) Pressure
Answer: b
Clarification: Temperature plays an important factor in thermal radiation. The heat capacity is defined as the ratio of amount of heat energy supplied and change in temperature. According to Stefan-Boltzmann Law, the total radiant heat power emitted from a surface is proportional to the fourth power of its absolute temperature.

9. According to ___________, the wavelength of the emitted radiation is inversely proportional to its frequency.
a) Fourier’s law
b) Pascal law
c) Newton law
d) Plank’s law
Answer: d
Clarification: According to Plank’s law, the wavelength of the emitted radiation is inversely proportional to its frequency. It is defined as the spectral density of the electromagnetic energy emitted by a black body in thermal equilibrium at a given temperature normally when the net flow of energy and matter is zero between the body and its environment.

10. ____________ gives the relationship between wavelength and temperature.
a) Fourier’s law
b) Wein’s law
c) Newton law
d) Plank’s law
Answer: b
Clarification: Wein’s law gives the relationship between wavelength and temperature. Wien’s displacement law is defined as the spectral radiance of black body radiation per unit wavelength. The maximum wavelength can be calculated by dividing Wien’s displacement constant with Temperature.

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250+ TOP MCQs on Process Engineering Applications – Meat Industry and Answers

Food Processing Unit Operations Multiple Choice Questions on “Process Engineering Applications – Meat Industry”.

1. What is meat emulsion?
a) Finely chopped meat mixture
b) Emulsifiers added to meat
c) By product of meat industry
d) Stabilizers added to meat
Answer: a
Clarification: A finely chopped meat mixture is usually called as meat emulsion. It consists of solid fat particles dispersed in a mixture of water and many fibrous particles, including connective tissue and muscle fibers.

2. Why is tumbling of meat recommended?
a) Avoid foaming
b) Increases efficiency
c) Increase efficacy
d) Decreases power consumption
Answer: a
Clarification: Tumblers are containers in the form of a cylinder rotating around the axis. Tumbling under vacuum is recommended to avoid foaming and to improve color stability.

3. What is the temperature of pasteurization for meat?
a) 73°C
b) 89°C
c) 63°C
d) 65°C
Answer: a
Clarification: Pasteurization is normally defined as a method of preserving food by heating it to temperatures under 100°C. It destroys the microbes and temperature of pasteurization for meat is 73°C.

4. Which of the following statements about heat treatment of meat products are correct?
Statement 1: To increase the shelf life of the product.
Statement 2: To obtain desirable organoleptic characteristics.
a) True, False
b) True, True
c) False, True
d) False, False
Answer: b
Clarification: During meat processing, meat products are subject to specific heat treatment. This is done to increase shelf-life by reduction of micro-organisms, obtain desirable organoleptic characteristics, to preserve nutritive value and improve digestibility of the product.

5. What is evisceration?
a) Removing internal body parts of bird
b) Removing feathers
c) Cleaning the skin of bird
d) Preservation technique of bird
Answer: a
Clarification: Evisceration is defined as removal of the internal organs of birds. After evisceration, the birds are placed in chiller baths of water and anti-microbial agents are added to reduce pathogen loading.

6. What is giblet harvester?
a) Removes the viscera from the body cavity
b) Separates the heart, liver, and gizzard from the rest of the viscera
c) Trim and clean gizzards
d) Cut the neck of the bird
Answer: b
Clarification: The liver, gizzard, and heart are separated by giblet harvester from the rest of the intestines by a saw. Then these organs are conveyed to a wash table where a prime cleaning is done.

7. What is arranger in meat processing?
a) Removes the viscera from the body cavity
b) Separates the heart, liver, and gizzard from the rest of the viscera
c) Trim and clean gizzards
d) Cut the neck of the bird
Answer: a
Clarification: Arranger removes the intestines from the body cavity and are arranged them for inspection. The initial removal is often skilled by the automatic vent opening mechanism. The arranger is also called as presenter.

8. What is the gizzard table operator in meat processing?
a) Removes the viscera from the body cavity
b) Separates the heart, liver, and gizzard from the rest of the viscera
c) Trim and clean gizzards
d) Cut the neck of the bird
Answer: c
Clarification: The gizzard table operators manually trim and clean the gizzards. They are then placed in an automatic splitting machine where they are opened up and washed in the gizzard peeler station.

9. Which of the following statements about stunning in meat processing are correct?
Statement 1: It reduces animal’s mobility.
Statement 2: Percussive stunning produces immediate unconsciousness through brain trauma.
a) True, False
b) True, True
c) False, True
d) False, False
Answer: b
Clarification: Stunning is the method of rendering animals unconscious or immobile, immediately prior to slaughtering. With percussive stunning, a device hits the animal on the head and produces immediate unconsciousness through brain trauma.

10. What gas is used for gas stunning in meat processing?
a) Argon
b) Helium
c) Carbon dioxide
d) Ammonia
Answer: a
Clarification: Gas stunning is the process where the animals are exposed to a mixture of breathing gases such as nitrogen and argon which produces unconsciousness and death through hypoxia. This process is not instantaneous.

250+ TOP MCQs on Mechanical Separation – Centrifugation and Answers

Food Processing Unit Operations Multiple Choice Questions on “Mechanical Separation – Centrifugation”.

1. What is the principle of centrifugation?
a) Sedimentation principle
b) Filtration principle
c) Evaporation principle
d) Size reduction principle

Answer: a
Clarification: Centrifuge works using the sedimentation principle, due to centrifugal acceleration denser substances move outward in the radial direction and that are less dense are displaced and move to the center.

2. What is called centrifugation?
a) Separated through spinning
b) Separate components at higher temperature
c) Separate components at lower temperature
d) Separated through evaporation

Answer: a
Clarification: Centrifugation is the process where a mixture is separated through spinning. It is used to separate skim milk from whole milk, washing machine and blood cells from your blood plasma.

3. Who invented centrifugation?
a) Newton
b) G.G. Stokes
c) Antonin Prandtl
d) Al-Kindi

Answer: b
Clarification: G.G. Stokes invented sedimentation. Newton discovered gravity. Antonin Prandtl invented centrifugation. Al-Kindi invented distillation.

4. What is use of density gradient centrifugation?
a) To purify viruses, ribosomes, membranes
b) Toremovedirt
c) To remove fine particles
d) To remove large particles

Answer: a
Clarification: Density gradient centrifugation is used to purify viruses, ribosomes, membranes. A sucrose density gradient is created by gently overlaying lower concentrations of sucrose on higher concentrations in centrifuge tubes where particles of interest are placed on top in ultracentrifuges. The particles move through the gradient until they reach the same sucrose density and fraction is removed and analyzed.

5. Which of the following statements about differential pelleting centrifugation are correct?
Statement 1: Tissue such as the liver is homogenized by this method.
Statement 2: The overlying solution is placed in another centrifuge tube for progressing steps.
a) True, False
b) True, True
c) False, True
d) False, False

Answer: b
Clarification: Differential pelleting centrifugation is the most common type of centrifugation used. Tissue like liver is homogenized.After sedimentation, the bottom is called pellet and an overlying solution called supernatant. The overlying solution is then placed in another centrifuge tube for progressing steps.

6. What is other name for zonal centrifugation?
a) Isopyniccentrifugation
b) Gradient centrifugation
c) Density gradient centrifugation
d) Differential centrifugation

Answer: b
Clarification: Zonal centrifugation is also known as band or gradient centrifugation and relies on the concept of sedimentation coefficient. In this process, a density gradient is created in a test tube with sucrose and high density at the bottom.

7. Which centrifugation depends on buoyant densities?
a) Isopynic centrifugation
b) Gradient centrifugation
c) Density gradient centrifugation
d) Differential centrifugation

Answer: a
Clarification: Isopynic centrifugation depends on buoyant densities, not on the velocities. CsCl, NaI gradients are the self-forming gradients for macromolecules and nucleotides under centrifugal force.

8. What are applications of centrifugation?
a) To separate two miscible substances and analyze the hydrodynamic properties of macromolecules
b) To separate two miscible substances and water treatment
c) Purification of mammalian cells and water treatment
d) Analyze the hydrodynamic properties of macromolecules and water treatment

Answer: a
Clarification: Applications of centrifugation are separation of two miscible substances, to analyze the hydrodynamic properties of macromolecules, purification of mammalian cells, separating chalk powder from water and removing fat from milk to produce skimmed milk.

9. Is centrifugation used in wine processing?
a) True
b) False

Answer: a
Clarification: Centrifugation is used in wine processing where the wine is clarified and stabilized by using centrifugation process.It is similar to sedimentation principle, where the centrifugal accelerates the denser substances to move outward in the radial direction and that are less dense are displaced and move to the center.

10. Which of the following statements about centrifugation are correct?
Statement 1: Particles are separated from a solution according to their size.
Statement 2: Particles are not separated from a solution according to their shape.
a) True, False
b) True, True
c) False, True
d) False, False

Answer: a
Clarification: Centrifugation is a process of separating substances which involves the centrifugal force. The particles are separated from a solution according to their size, shape, density, the viscosity of the medium and rotor speed.

250+ TOP MCQs on Membrane Separators and Answers

Food Processing Unit Operations Multiple Choice Questions on “Membrane Separators”.

1. What is pervaporation?
a) Process to separate a volatile liquid from a non-volatile liquid
b) Process to mix a volatile liquid from a non-volatile liquid
c) Process to a evaporate a non-volatile liquid
d) Process to separate water molecules from a non-volatile liquid
Answer: a
Clarification: Pervaporation is a process to separate a volatile from a non-volatile liquid. The driving force is a vacuum on the gaseous side of the membrane. It is a tool for separation of liquid mixtures.

2. Which method is used for removing hardness?
a) Nanofiltration
b) Pervaporation
c) Electrodialysis
d) Reverse Osmosis
Answer: a
Clarification: Nano filtration is used for removing hardness. It removes organic compounds and selected salts at the lower pressure than RO system. It separates at the molecular level, removing all suspended solids and most dissolved solids.

3. Which method is used separation of azeotrope mixtures?
a) Nano filtration
b) Pervaporation
c) Electro dialysis
d) Reverse Osmosis
Answer: b
Clarification: Pervaporation is a process to separate a volatile from a non-volatile liquid. The driving force is a vacuum on the gaseous side of the membrane. It is a tool for separation of liquid mixtures.

4. Which of the following uses aromatic polyamide as membrane?
a) Gas separation
b) Pervaporation
c) Electro dialysis
d) Reverse Osmosis
Answer: d
Clarification: Reverse Osmosis uses aromatic polyamide as membrane where it is used in separation of salts and micro-solutes from solutions.

5. Which of the following statements about electro dialysis are correct?
Statement 1: Cation and anion exchange membrane is used.
Statement 2: The membrane is made of polymers & co-polymers.
a) True, False
b) True, True
c) False, True
d) False, False
Answer: a
Clarification: Cation and anion exchange membrane is used in electro dialysis where the membrane is made of sulfonated cross-linked polystyrene and is used in desalting the water.

6. What is other name for polymeric membrane?
a) Organic membrane
b) Inorganic membrane
c) Cation and anion membrane
d) Neutral charge membrane
Answer: a
Clarification: Polymeric membranes are also known as organic membranes. In order of the coarsest separation to the finest are microfiltration, ultrafiltration, nanofiltration and reverse osmosis.

7. What is flux rate for filters?
a) Ratio of flow to the membrane area
b) Ratio of concentration to the membrane area
c) Ratio of membrane area to the flow of the solution
d) Ratio of viscosity to the membrane area
Answer: a
Clarification: A membrane’s flux is defined as ratio of flow to the membrane area. It is used for calculating scalability. Ultrafiltration membranes are used in the purification of expensive biomolecules.

8. What is membrane processing?
a) Process that concentrates and separates without the use of heat
b) Process that removes dust without the use of heat
c) Process that remove water without the use of heat
d) Process that remove alcohol without the use of heat
Answer: b
Clarification: Membrane processing concentration and separation without the use of heat. Particles are separated on the basis of size of the molecules and shape with the help of pressure gradient and uses semi-permeable membranes.

9. What are cleaning techniques for the removal of membrane fouling?
a) Air flushing and chemical flushing
b) Alcohol flushing and chemical flushing
c) Air flushing and alcohol flushing
d) Air flushing
Answer: a
Clarification: There are various cleaning techniques to remove membrane fouling. These are forward flushing, backward flushing, air flushing and chemical cleaning.

10. Which of the following is used to remove yeast?
a) Nano filtration
b) Micro filtration
c) Electro dialysis
d) Reverse Osmosis
Answer: b
Clarification: Micro filtration is used for removing yeast, E- coli and mist droplets. Reverse Osmosis and nano filtration is used for removing inorganic compounds.