Category: Food Packaging Technology Objective Questions

Food Packaging Technology Interview Questions and Answers for freshers on “Blending and Vapor Deposition in Thermoplastics”.

1. Smart blending works on the principle of ________
a) Chaotic addition
b) Chaotic advection
c) Chaotic adversion
d) Chaotic abstraction
Answer: b
Clarification: Smart blending works on the principle of chaotic advection. It refers to the chaotic (non-periodic) motion of a particle in a fluid that can occur even where the flow field is simple and periodic, which causes successive shear deformations and reorientations.

2. A __________ is a highly concentrated blend of an additive and a carrier resin.
a) Masterpolymer
b) Mastermixture
c) Masterbatch
d) Masterblend
Answer: c
Clarification: A masterbatch is a highly concentrated blend of an additive and a carrier resin. A masterbatch is a highly concentrated blend of an additive with a a carrier resin that should be compatible and miscible in the resin into which it is being blended. Film manufacturers commonly blend a masterbatch into the resin at the extruder feed hopper when making film or sheet.

3. Which of the following metal is not used in vacuum metallization?
a) Aluminium
b) Nickel
c) Chromium
d) Sodium
Answer: d
Clarification: Sodium is not used in metallization. Vacuum metallization is a method in physical vapour deposition process and produces coatings by thermal evaporation of metals in a vacuum. Physical method includes vaporization of the metal, which is later deposited on the surface by condensation.

4. Which of the following is not a heating source in metallization?
a) Convection heating
b) Resistance heating
c) Induction heating
d) Electron beam heating
Answer: a
Clarification: Convection heating is not a heating source in metallization. In resistance heating, aluminium wire is fed onto a block of metal that is heated by holding it in a carbon crucible or boat across which a high current is arched. A pool of melted metal forms in the boat cavity and evaporates into a cloud above the source. In induction heating, heating is done by passing a high current through heating coils, causing an induced magnetic field inside the coils. In electron beam heating, the source is heated by electron beam.

5. Energy of an electron is upto ______ in electron beam heating.
a) 15eV
b) 15keV
c) 30eV
d) 30keV
Answer: b
Clarification: Energy of an electron is upto 15keV in electron beam heating. Electron beam heating allows tight control of the evaporation rate and although more expensive, it is notably simpler and much more versatile as it can be used to evaporate many different materials. It must be ensured that no secondary electrons impinge on the polymeric web.

6. Adding more metal during the metallization process increases barrier properties.
a) True
b) False
Answer: a
Clarification: The given statement is true. Metallization process has a strong and complex effect on the development of adhesive and barrier properties of metallized films. Thicker films leads to adhesion problems and even flaking, if the metallized layer becomes too thick. The thinner coatings tend to be full of pinholes and may even be transmitted lights to some degree.

7. __________ is a PVD technique in which the bulk material is released into the vacuum by bombardment from an ion source.
a) Splattering
b) Sputtering
c) Splashing
d) Spreading
Answer: b
Clarification: Sputtering is a PVD technique in which the bulk material is released into the vacuum by bombardment from an ion source. The material coalesces onto the substrate surface, thus forming a thin film.

8. _____________ involves depositing successive layers of different substances to produce layered, crystalline films.
a) Atomic layer chemical vapor deposition
b) Combustion chemical vapor deposition
c) Low pressure chemical vapor deposition
d) Plasma enhanced chemical vapor deposition
Answer: a
Clarification: Atomic layer chemical vapor deposition (ALCVD) involves depositing successive layers of different substances to produce layered, crystalline films. In short, ALCVD is a method in chemical vapor deposition in which deposition occurs through chemisorption of pulsed chemical reactant.

9. In Plasma Enhanced Chemical Vapor Deposition, deposition occurs at a _______ temperature.
a) Higher
b) Constant
c) Increasing
d) Lower
Answer: d
Clarification: In Plasma Enhanced Chemical Vapor Deposition, deposition occurs at a low temperature. The use of plasma helps to deposit thin films from a gaseous state to a solid state on the substrate; hence it enhances chemical reaction rates. The plasma is created by alternating or direct current discharge between two electrodes. The space between electrodes is filled with reacting gases which contains reactive ions and radicals.

10. Which film is used for improving barrier properties of PET bottles?
a) PVC
b) PED
c) DLC
d) GLC
Answer: c
Clarification: DLC (Diamond like Carbon) film is used for improving barrier properties of PET bottles. There is deposition of a very thin DLC film on the inner surface of PET bottle by PECVD mechanism. DLC film provides gas barrier properties, flavour barrier, UV barrier, chemical inertness, recyclability, etc.

11. Which of the following CVD technique is a flame based technique?
a) CCVD
b) PECVD
c) LPCVD
d) ALCVD
Answer: a
Clarification: CCVD (Combustion Chemical Vapor Deposition) is a flame based technique. In this, the metal-bearing chemicals are first dissolved in a solution that typically is a combustible fuel. The solution is then atomized to form microscopic droplets that are carried by an O₂ stream to the flame where they are combusted. The heat from the flame provides the energy required to vaporize the droplets and for the precursors to react and deposit on the substrate.

Food Packaging Technology Multiple Choice Questions & Answers (MCQs) on “Properties of Glass”.

1. Which of the following is used for the hot and surface treatment of glass?
a) Calcium Oxide
b) Zinc Oxide
c) Tin Oxide
d) Copper Oxide
Answer: c
Clarification: Tin Oxide is used for the hot and surface treatment of glass. It is an inorganic compound consisting of tin and oxygen. It is commonly used to create customized glass by giving transparent glass an opaque, porcelain-like, opaque appearance.

2. What are White flints?
a) Lacquered aluminum cans
b) Brown glass
c) Colorless glass
d) Translucent laminates
Answer: c
Clarification: Standard White flint glass is colorless. White flint glass is defined as a glass of high optical purity and low iron content. Made with the highest quality raw materials, super flint glass is produced using virgin batch materials. This means that more energy is required to melt the materials to the desired quality level.

3. A finish is a part of glass bottles where _________
a) labels are posted
b) cracks can never be formed
c) colors can never be applied
d) closures are applied
Answer: d
Clarification: Finish is a part of glass bottles where closures are applied. Finish is the part of the bottle that holds the cap or closure, the glass surrounding the opening in the container.

4. Which if the following is used to reduce coloration?
a) CeO₂
b) TiO₂
c) Na₂S
d) Co₃O₄
Answer: a
Clarification: The addition of CeO₂ (it is reduced to Ce₂O₃ by the radiations) in glasses in amounts up to 1.5% has proved an effective means of reducing coloration. Unfortunately, it is a very expensive oxide, so glass containers treated this way are significantly more costly than standard containers.

5. Which of the following is used to give amber color to glass?
a) CdS + Se
b) Cu₂O + CuO
c) NiO
d) Na₂S
Answer: d
Clarification: Na₂S is used to give amber color to glass. CdS + Se is used to give orange color to glass. NiO is used to give purple color to glass. Cu₂O + CuO is used to give blue color to glass.

6. Which of the following gives black color to glass?
a) MnO
b) CdS
c) Sb₂S₃
d) Co₃O₄
Answer: d
Clarification: Co₃O₄ (+ Mn, Ni, Fe, Cu, Cr oxides) gives black color to glass. Sb₂S₃ gives red color to glass. CdS gives yellow color to glass. MnO gives brown color to glass.

7. The principle of fracture analysis in glass is based on Young’s modulus.
a) True
b) False
Answer: a
Clarification: The given statement is true. The principles of fracture analysis or diagnosis of the cause(s) of glass container breakage has the following four aspects:
i. Internal pressure resistance
ii. Vertical load strength
iii. Resistance to impact
iv. Resistance to scratches and abrasions.

8. Mechanical strength of a bottle or jar can increase with glass weight.
a) True
b) False
Answer: a
Clarification: The given statement is true. Although the mechanical strength of a bottle or jar can increase with glass weight, this is at the expense of thermal strength which decreases with increasing glass weight. Considerable expertise is required by the glassmaker to determine the most appropriate design to satisfy the mechanical strength requirements and to balance the thermal strength demands of the finished product.

9. Glass has the most resistance to temperature changes relative to other packaging materials.
a) True
b) False
Answer: b
Clarification: The given statement is false. Relative to other forms of food packaging, glass has the least resistance to temperature changes. The resistance to thermal failure depends on the type of glass employed, the shape of the container and the wall thickness. When a glass container is suddenly cooled, tensile stresses are set up on the outer surfaces, with compensating compressional stresses on the inner surface. Conversely, sudden heating leads to surface compression and internal tension.

10. Glass loses its ability to transmit light on irradiation.
a) True
b) False
Answer: True
Clarification: The given statement is true. Glasses and other transparent materials tend to darken and lose much of their ability to transmit light when bombarded by high energy radiations such as those used in food irradiation. There are two principal causes of this coloration of glass. First, the displacement of electrons can create holes which could lead to formation of color centers. Second, changes in the valence shell of metal oxides can result in increased absorption of light in the visible wavelength.

Food Packaging Technology Multiple Choice Questions & Answers (MCQs) on “Orientation of Thermoplastic Films”.

1. The term BOPP in packaging stands for _____
a) Biaxially Oriented Polypropylene
b) Biaxially Oriented Propylene Alcohol
c) Biaxially Oriented polyphenol
d) Biaxially Operated Packaging Printing
Answer: a
Clarification: The term BOPP in packaging stands for Biaxially Oriented Polypropylene. It is generally used for packaging labels. BOPP is produced by stretching the polypropylene film in both directions. It results in higher strength and higher resistance to stress cracking and puncture.

2. Which of the following is used for shrink bundle?
a) BOPP
b) PVC
c) LLDPE
d) Cast PP
Answer: c
Clarification: LLDPE-Linear Low Density Polyethylene is used for shrink bundling. LLDPE is a copolymer made up of ethylene and another longer olefin, whereas LDPE is a homopolymer made only of ethylene monomers. LLDPE has a greater tensile strength or resistance to harsh environment.

3. Oriented films have better sealability.
a) True
b) False
Answer: b
Clarification: The above statement is false. Oriented film cannot be easily heat sealed because it shrinks and puckers at temperatures below the sealing temperature.

4. LDPE is generally irradiated before moulding into film.
a) True
b) False
Answer: a
Clarification: The given statement is true. LDPE is generally irradiated before moulding into film, because radiation cross-links the molecules and the film can be stretched without becoming fluid at the melting point of a non-irradiated film, resulting in greatly improved tensile strength and shrink tension compared to non-irradiated LDPE.

5. __________ is the process which reduces the residual strain after the extrusion process.
a) Lacquering
b) Canning
c) Electroplating
d) Annealing
Answer: d
Clarification: Annealing is the process which reduces the residual strain after the extrusion process. Films can be annealed by the application of heat to partially relax the forces while maintaining the film in a highly stretched condition. It is then cooled to room temperature and the restraint on the film released.

6. The film after annealing is called ________
a) Strict film
b) Film set
c) Heat set
d) Heat film
Answer: c
Clarification: The film after annealing is called heat set. Heat set does not shrink even if heated below the annealing temperature. Heat set has more desirable properties. Annealing results in some reduction in dimension in the stretched direction or directions.

7. Which of the following methods are used for orientation of plastic films?
a) Tenter frame and bubble frame
b) Tenter frame and Double bubble
c) Tenter bubble and Double bubble
d) Tenter bubble and Double Frame
Answer: b
Clarification: Tenter frame and Double bubble are the two methods are used for orientation of plastic films. It generally includes heating of the film and stretching it in uniaxial or biaxial direction on a tenter or double frame. The orientation decides the use of the film.

8. The temperature of orientation is ______ the flow temperature and _____ the glass transition temperature.
a) above, above
b) above, below
c) below, below
d) below, above
Answer: d
Clarification: The temperature of orientation is below the flow temperature and above the glass transition temperature. When the temperature of the film is above glass transition temperature and below flow temperature, the molecules readily glide past one another when the material is stressed. This is the optimal temperature for stretching the thermoplastic film. As a result of this stretching, the direction of the molecules changes toward that in which the material is stressed, and the molecules are extended like springs. The lower temperature enables the setting the configuration of molecules in the strained position.

9. Orientation increases permeability.
a) True
b) False
Answer: b
Clarification: The given statement is false. Orientation decreases permeability. It is because orientation decreases both, the diffusion and solubility coefficient of the plastic film.

10. Which of the following does not affect stretch rate in tender frame process?
a) Extent of orientation
b) Divergence angle
c) Feed rate
d) Chain speed
Answer: c
Clarification: Feed rate does not affect stretch rate in tender frame process. Stretch rate is determined by the chain speed, divergence angle and extent of orientation. The thermoplastic film is stretched in the machine direction (MD) and the extent of orientation is determined by the ratio of the width of the film entering to the width of the film leaving the system. The film is then fed to a tender frame where a series of clips (mounted side by side on endless chains that diverge at constant angle) grasp both edges of the film and draw it in the transverse direction (TD) as it travels forward at an increasing speed.

11. Draw ratios in tender frame process ranges from ______ to _____
a) 4:1, 10:1
b) 2:1, 10:1
c) 3:1, 10:1
d) 5:1, 10:1
Answer: a
Clarification: Draw ratios in tender frame process ranges from 4:1 to 10:1. It is for both the directions- Machine Direction (MD) and Transverse Direction (TD). In the tender frame process, the thermoplastic film is first stretched in the machine direction and then the transverse direction.

12. The orientation % in BOPP by the double bubble process lies between _________
a) 200-1000
b) 200-800
c) 700-800
d) 700-1000
Answer: c
Clarification: The orientation % in BOPP by the double bubble process lies between 700-800%. This happens because of the elastic memory of Polypropylene, which leads to shrinkage of the film after orientation.

13. The amount of orientation imparted to a film depends on the amount of quench.
a) True
b) False
Answer: a
Clarification: The given statement is true. The amount of orientation imparted to a film depends on the stretching temperature, the amount of stretching, the rate of stretching and the quench. The extent of orientation is increased by decreasing the stretching temperature, increasing the amount of stretch, increasing the rate of stretch and increasing the amount of quench.

14. Films with glass transition temperature below room temperature have more crystallisation rate.
a) True
b) False
Answer: a
Clarification: The given statement is true. Films with glass transition temperature below room temperature have more crystallisation rate. PVdC copolymer and PP are an example. They show appreciable crystallization rate even at room temperature and, therefore, have to be quenched and oriented immediately after extruding.

15. The property of a thermoplastic film to return to its original size is called ______
a) Elasticity
b) Shrinkiness
c) Elastic memory
d) Shrinkability
Answer: c
Clarification: The property of a thermoplastic film to return to its original size is called elastic memory. It is the potential energy stored in the extended molecules which is a characteristic of oriented, non-heated set thermoplastics. When such a film is reheated to its orientation temperature, it shrinks as the molecules tend to return to their original size and spatial arrangement.

Food Packaging Technology Multiple Choice Questions & Answers (MCQs) on “Manufacture of Glass – 1”.

1. Cullet is the second largest constituent in glass.
a) True
b) False
Answer: a
Clarification: The given statement is true. The largest constituent (68%–73%) is silica; the second largest constituent (15%–50%) is cullet, originating both as glass scrap from the factory and recycled glass from consumers (so-called postconsumer glass).

2. _______ glass is the most color sensitive.
a) Yellow
b) Black
c) Flint
d) Amber
Answer: c
Clarification: Flint glass is the most color sensitive with a tolerance of 1% green or 5% amber cullet in the batch mix. Amber glass can tolerate 10% green cullet, while up to a 50% mixture of amber and flint cullet can be used in the production of green glass.

3. Using cullet in glass making increases the energy requirement.
a) True
b) False
Answer: b
Clarification: The given statement is false. Cullet also reduces the amount of dust and other particulate matter that often accompanies a batch made exclusively from new raw materials. The use of cullet is economically desirable since less energy is required to melt cullet than new raw materials.

4. The temperature of glass-melting furnace is around ______
a) 800°C
b) 1000°C
c) 1100°C
d) 1500°C
Answer: d
Clarification: The raw materials are weighed, mixed and charged into a glass-melting furnace, which is maintained at a temperature of approximately 1500°C. Here, they are converted into molten glass that is chemically homogeneous and virtually free of gaseous inclusions (bubbles). The melting process consists of two phases: (i) changing the solids into a liquid and (ii) fining or “clearing up” of the liquid.

5. The process of removal of gases from glass surface is known as ___________
a) pressurization
b) refining
c) vaporisation
d) forming
Answer: b
Clarification: During the refining process, gases (principally CO₂, SO₂ and water vapor) produced by the chemical reaction rise to the surface of the furnace and are removed. It moves from the furnace into the working end of the furnace (mistakenly called the refiner) where thermal homogenization and cooling of the glass to the viscosity required for the particular operation begin.

6. During removal of gases, the temperature of melt increases.
a) True
b) False
Answer: b
Clarification: The given statement is false. During removal of gases, the temperature of melt decreases. The temperature of the melt is lowered from 1250°C to 1350°C to approximately 1100°C.

7. Which is the next step after refining in manufacture of glass?
a) Blowing
b) Forming
c) Annealing
d) Moulding
Answer: b
Clarification: The step after refining in manufacture of glass is forming. In this, the molten glass is molded into the desired shape. When the molten glass becomes free of gas (seed-free), it is then ready for forming into containers.

8. Gob is formed in a channel-like structure called a forehearth.
a) True
b) False
Answer: a
Clarification: The given statement is true. The glass is carried from the working end of the furnace to the forming machine in a channel-like structure called a forehearth, which is fired by a number of small burners, the aim being to ensure uniform temperature distribution throughout the depth of the glass. The glass then passes through a gob-forming mechanism which consists of a rotating sleeve and vertical plunger.

9. What is the temperature during the formation of the gob?
a) 1100°C
b) 2000°C
c) 500°C
d) 800°C
Answer: a
Clarification: Precise control of temperature and shape during the formation of the gob is required for the high speed production of accurately formed glass containers. Temperatures in the vicinity of 1100°C varying by no more than ±1°C are typical.

10. The process of converting gob of glass into a bottle or jar is called _________
a) threading
b) moulding
c) forming
d) annealing
Answer: c
Clarification: The process of converting a cylindrically shaped gob of glass into a bottle or jar is called forming, and it is essentially a controlled cooling process. While various types of forming machines are used throughout the world, the most predominant type is the IS machine. As its name implies, it consists of up to 16 sections, each one an individually functioning, hollow glass machine. It performs two basic functions: it shapes the gob into a hollow container, and simultaneously removes heat from the gob to prevent it from deforming significantly under its own weight.

11. Molten glass is also known as _________
a) body
b) gob
c) lump
d) mass
Answer: b
Clarification: The glass exits in a continuous, viscous stream which is cut by rapidly moving, horizontal steel blades to form what is known as a “gob” (i.e., a mass or lump of molten glass).

12. What is the preform before the formation of final glass jar called?
a) Mold
b) Gob
c) Tube
d) Parison
Answer: d
Clarification: The preform before the formation of final glass jar called parison or body blank. A gob of glass, accurately sheared in terms of weight and shape, is delivered into an externally air cooled, cast iron mold from above to shape a preform.

12. The pressure temperature combination in formation of glass container is around?
a) 200 kPa, 650°C
b) 100 kPa, 750°C
c) 200 kPa, 500°C
d) 500 kPa, 150°C
Answer: a
Clarification: Air at about 200 kPa is applied so that the glass is pressed against the metal surface of the blow mold, which is air-cooled to ensure rapid removal of heat. After this, the mold is opened and fully blown parison (at approximately 650°C) is removed. It is then held over a deadplate to further cool it.

13. The parison is an important factor in determining the final shape and structure of glass jar.
a) True
b) False
Answer: a
Clarification: The given statement is true. The body blank or parison is formed by pressing the gob of molten glass against the mold walls with a large plunger. The cavity is filled with molten glass, which is then pushed down into the neck ring to form the finish. A mechanical plunger in introduced into the glass which gives it a shape. Baffle or counterblow air is not used during this operation.

14. Which of the following methods is used for manufacture of lightweight bottles?
a) Screw press and blow
b) Blow and blow
c) Narrow neck press and blow
d) Neck blow and press
Answer: c
Clarification: Narrow neck press and blow (NNP&B) is a used for manufacture of lightweight bottles. It is the process in which the gob is delivered into the blank mold and pressed by a metal plunger. The plunger and gob together have the same volume as the blank mold cavity.

15. The gob is transferred to ___________ after moulding.
a) roller
b) plunger
c) former
d) annealing lehr
Answer: d
Clarification: The gob is transferred to annealing lehr after moulding. The term annealing generally refers to the removal of stress, and the annealing temperature or point is defined as the temperature at which stresses in the glass are relieved in a few minutes.

Food Packaging Technology Multiple Choice Questions & Answers (MCQs) on “Thermoplastic Polymers – Shrink and Stretch Films”.

1. Which of the following is not used as a stretch film?
a) Polyolefins
b) PVC
c) PVdC
d) PET
Answer: d
Clarification: PET is not used as a stretch film. PET has its greatest use in bottles for juices and soft drink due to its barrier and mechanical properties. Shrink films are composed of three basic categories: polyolefins, PVC and PVdC copolymer.

2. LLDPE is produced by copolymerisation of ethylene with ______
a) Di-olefins
b) Gamma olefins
c) Beta olefins
d) Alpha olefins
Answer: d
Clarification: LLDPE is produced by copolymerisation of ethylene with alpha olefins. LLDPE- Linear Low Density Polyethylene has better stretch properties when compared to LDPE- Low Density Polyethylene.

3. PVDC stands for ________
a) Polyvinylidene Chloride
b) Polyvinyl Dichloride
c) Polyvinyldeca Chloride
d) Polyvinyldiene Chloride
Answer: a
Clarification: PVDC stands for Polyvinylidene Chloride. PVdC is a polymer of Vinylidene chloride. PVDC is also known as coated PVC. PVDC has lower OTR and WVTR when compared to PVC, by a factor of 5-10.

4. A plastic wrap is the same as stretch wrap.
a) True
b) False
Answer: b
Clarification: The above statement is false. A plastic wrap is same as shrink wrap. It is the shrink wrap used in foods. It is used to wrap food items, so as to preserve them for a longer period of time. The most commonly used plastic wrap is PVC.

5. BOPP stands for __________
a) Biaxially operated polypropylene
b) Biaxiallyoriented propylene
c) Biaxiallyoriented packaged propylene
d) Biaxially oriented polypropylene
Answer: d
Clarification: BOPP stands for biaxially oriented polypropylene. BOPP is mostly used in packaging labels. It is a product of heat-setting, the process in which a film is reheated in a constrained strain. It is produced by the tenderframe technology for orientation of plastic films.

6. Find the odd one.
a) Cling film
b) Plastic wrap
c) Saran wrap
d) Stretch film
Answer: d
Clarification: Stretch film is the odd one. Cling film, plastic wrap and saran wrap are the terms which denote a thin plastic film used for packaging of food. It is also known as shrink wrap and food wrap. Stretch film is used for wrapping secondary or higher forms of packaging. It can never be used as a primary packaging material.

7. In __________ no sealing is required.
a) Plating
b) Laminating
c) Stretch wrapping
d) Shrink wrapping
Answer: c
Clarification: In stretch wrapping, no sealing is required. Its main function is pallet unitizing. During stretch wrapping, the material is covered in such a way that the film’s elasticity holds the load tightly together and hence, no sealing is required.

8. Which of the following polymer is used as a shrink film for foods and snacks?
a) PE
b) PP
c) PVC
d) Polyolefin
Answer: d
Clarification: Polyolefin films are used for shrink wrapping of foods, snacks and retail items. It is a clear film that shrinks evenly in all directions. This film allows scents to permeate it. Since it requires high temperatures to shrink the film, it’s often applied with a shrink wrap machine which increases productivity and allows items to be bundled together.

9. Which of the following polymer is used as a shrink film for CDs and DVDs?
a) PE
b) PP
c) PVC
d) Polyolefin
Answer: c
Clarification: PVC- Polyvinyl Chloride is used as a shrink film for CDs and DVDs (and also Blu-ray discs). PVC shrink films have high strength with good clarity and gloss. Its major use is in shrink wrapping CDs, DVDs and discs, but is also used for shrink wrapping of books, toys and food items.

10. Thermosetting polymers can be used for shrink or stretch wrapping.
a) True
b) False
Answer: b
Clarification: The above statement is false. Thermosetting plastics cannot be used as shrink or stretch films. There are only four types of thermoplastics used for shrink wrapping currently, which include – Polyethylene, Polypropylene, Polyolefin and Polyvinyl Chloride.

11. Which of the following polymer is used for wrapping large and bulky items?
a) PE
b) PP
c) PVC
d) Polyolefin
Answer: a
Clarification: PE- Polyethylene is used for wrapping large and bulky items. PE shrink films are thicker, stronger and more durable than other shrink films. PE shrink films are often used to wrap bottled water, canned goods and other heavy objects. It is deal for wrapping large and bulky items during transit. These films are so strong that they can replace corrugated boxes.

12. Which of the following polymer is also called general purpose shrink film?
a) PE
b) PP
c) PVC
d) Polyolefin
Answer: b
Clarification: Polypropylene film is also known as general purpose shrink film. It is because this is the most used plastic for wrapping retail items. It has the property of shrinking at low temperatures while providing durable seals.

13. Which of the following is not a type of overwrap?
a) Decorative wrap
b) Paper wrap
c) Stretch wrap
d) Shrink wrap
Answer: c
Clarification: Stretch wrap is not a type of overwrap. An overwrap is also known as a polywrap. Shrink wrap is a polymer plastic film, which shrinks on the application of heat. Paper wrap, like Kraft paper is used to overwrap items in a package or to overwrap a package. Decorative packaging is the quaternary packaging, which aims to enhance the looks of the good.

Food Packaging Technology MCQs on “Manufacture of Glass – 2”.

1. Lehr is a deadplate.
a) True
b) False
Answer: b
Clarification: The given statement is false. The containers, from the molder, are transferred from the deadplate to a large oven, known as a lehr, which is equipped with a belt conveyer.

2. The temperature during annealing is around ______
a) 250°C
b) 340°C
c) 540°C
d) 640°C
Answer: c
Clarification: This is achieved by raising the temperature of the container to approximately 540°C, holding it there for a few minutes and then cooling at a rate which is consistent with the removal of stress from a predetermined wall thickness.

3. The temperature at which annealing is done is known as _________
a) melting point
b) softening point
c) transition point
d) gradient point
Answer: b
Clarification: The temperature at which annealing is done is known as softening point of glass. It melts and reforms glass so that any cracks or deformity can be healed or removed.

4. The primary purpose of annealing is to improve transparency of glass.
a) True
b) False
Answer: b
Clarification: The given statement is false. The function of the annealing lehr is to produce a stable product by removing any residual stresses resulting from non-uniform cooling rates during forming and handling.

5. During cooling, the outside surface is hotter than the inside.
a) True
b) False
Answer: b
Clarification: The given statement is false. During cooling, the inside surface is hotter than the outside; this results in compression on the outer surface but tension at the inner surface. Sudden cooling results tensile stresses into the outer surfaces and compressional stresses in the interior surfaces. Poor annealing may result in breaking or cracking if interior is bruised or tension is high.

6. Lightweight bottles can handle temperature fluctuation better than regular bottles.
a) True
b) False
Answer: a
Clarification: The given statement is true. Due to the better thickness distribution of lightweight glass bottles, they withstand a maximum temperature difference (progressive thermal shock) of 5°C–10°C higher than the regular weight bottles.

7. Narrow-neck glass containers are formed by _______ process.
a) blow and press
b) press and press
c) press and blow
d) blow and blow
Answer: d
Clarification: Narrow-neck glass containers (bottles) are formed by blow and blow process. Bottles are made by a two step Blow & Blow process, in which a gob of glass is sent to a cast iron mold. The cast iron mold is externally air cooled and hence changes gob to a perform (also known as a parison or body blank).

8. Wide-mouth glass containers are formed by _______ process.
a) blow and press
b) press and blow
c) blow and blow
d) press and press
Answer: b
Clarification: Wide-mouth glass containers (jars) are formed by press and blow process. In the case of jars, a two-step WMP&B process is used. The body blank or parison is formed by pressing the gob of molten glass against the mold walls with a large plunger. When the cavity is filled, glass is then pushed down into the neck ring and the finish is formed.

9. Formation of glass jars takes place through blow moulding.
a) True
b) False
Answer: a
Clarification: The given statement is true. When the finish molding is complete, the plunger is retracted and air blown in from the bottom of the mold, enlarging the size of the bubble until the glass is pressed out against the blank mold to form a hollow, thick-walled preform or parison. The parison is then inverted and transferred to the blow mold. It elongates there as a result of its own weight and touches the base of the mold.

10. In the blow and blow process for glass container manufacture, the neck formation takes place before blank is blown.
a) True
b) False
Answer: a
Clarification: The given statement is true. The blow and blow process takes place in the following steps-
i. Gob dropped into blank mold
ii. Neck formed
iii. Blank blown
iv. Blank transferred to blow mold
v. Final shape blown
vi. Finished bottle.

11. Wide mouth press and blow process for glass container manufacture does not include which of the following steps?
a) Blank press
b) Neck formation
c) Final shape blown
d) Plunging
Answer: b
Clarification: Wide mouth “press and blow” process for glass container manufacture takes place in the following steps-
i. Gob dropped into blank mold
ii. Plunger presses blank shape
iii. Blank pressed Blank transferred to blow mold
iv. Final shape blown
v. Finished jar– give bullet points.

12. Impact strength of lightweight bottles is more than regular bottles.
a) True
b) False
Answer: a
Clarification: The given statement is true. The impact strength of lightweight bottles is more than regular bottles. It is because, lightweight glass bottles have a more homogenous thickness distribution. It also has a superior vertical load strength and better impact strength, especially in the heel.

13. In narrow neck press and blow (NNP&B) process, the plunger and gob together have the same volume as the blank mold cavity.
a) True
b) False
Answer: a
Clarification: The given statement is true. In narrow neck press and blow process, the plunger and gob together have the same volume as the blank mold cavity. In this, the gob is delivered into the blank mold. It is then pressed by a metal plunger to give it a shape.

14. What enables the glassmaker to decide exactly how the glass is distributed in the parison?
a) Density of gob and plunger
b) Mass of gob and plunger
c) Volume of gob and plunger
d) Temperature of gob and plunger
Answer: c
Clarification: The volume of gob and plunger enables the glassmaker to decide exactly how the glass is distributed in the parison and, hence, to be able to more accurately control the uniformity of glass distribution in the finished container. Indeed, weight savings of up to 30% can be made. The second stage is similar to the B&B process.

15. What accounts for greater impact strength of lightweight bottles?
a) Uniform distribution of weight
b) Uniform distribution of pressure
c) Uniform distribution of volume
d) Uniform distribution of density
Answer: a
Clarification: The uniform distribution of weight accounts for greater impact strength of lightweight bottles. The parison is blown to a finished container having a more uniform wall thickness and, as a result, higher strength.

MCQs on all areas of Food Packaging Technology,