Category: Food Packaging Technology Objective Questions

Food Packaging Technology Multiple Choice Questions & Answers (MCQs) on “ Extrusion and Calendering in Thermoplastics”.

1. Which of the following is not a type of calender?
a) I type
b) L type
c) Z type
d) M type
Answer: d
Clarification: M type is not a type of calender. In I type of roller setup, the rollers are placed horizontally. In L type arrangement of roller setup, is I type setup mirrored vertically. In Z type arrangement of rollers, each pair of rollers is placed at right angles to the next pair in chain.

2. Calendering and extrusion are similar processes.
a) True
b) False
Answer: b
Clarification: This is a false statement. Calendering and extrusion are different processes. Extrusion is a process of passing the molten plastic through a shaping device, to give it any form. Whereas, calendering is a complementary process to film and sheet extrusion, which involves the formation of continuous sheets of controlled thickness by passing plastic materials through rollers.

3. As defined by ASTM, the thickness of a plastic film (after single extrusion) should be not more than ________
a) 0.25mm
b) 0.50mm
c) 0.01cm
d) 1mm
Answer: a
Clarification: As defined by ASTM, the thickness of a plastic film (after single extrusion) should be not more than 0.25mm. ASTM, American Society for testing materials is an international standards organisation which functions to set standards for miscellaneous materials.

4. Which of the following is not used for conversion of extruded plastic into sheets?
a) Cast Film Extrusion
b) Slit Die Extrusion
c) Blown Film Extrusion
d) Micro Extrusion
Answer: d
Clarification: Micro Extrusion is not used for conversion of extruded plastic into sheets. Micro extrusion is the process to create comparatively smaller sized objects. Whereas, Cast Film Extrusion, Slit Die Extrusion and Blown Film Extrusion are used for conversion of extruded plastic into sheets.

5. Tubular Extrusion is also known as _______
a) Flat Film Extrusion
b) Blown Film Extrusion
c) Slit Die Extrusion
d) Cast Film Extrusion
Answer: b
Clarification: Tubular Extrusion is also known as Blown Film Extrusion. Flat Film extrusion is also known as Cast Film and Slit Die Extrusion. Like Flat Film Extrusion, Tubular extrusion is also used to convert extruded plastic into sheets. It is done by blowing air through the center of tubular die, due to which the thin tube from extruder is inflated into a thin bubble and cooled, after which it is flattened and wound up.

6. Compression ratios for single screw extrusion should lie between ____ and ____
a) 2:1, 3:1
b) 1:2, 4:1
c) 2:1, 4:1
d) 1:2, 1:3
Answer: c
Clarification: Compression ratios for single screw extrusion should lie between 2:1 and 4:1. Compression ratio is an important parameter for any extrusion process. Compression ratio is the ratio of the volume of one flight of the screw at the in-fees end to the volume of one flight at the die end.

7. The term BUR in extrusion and calendering of thermoplastics refers to _______
a) Blow Up Ratio
b) Bauxime Up Ratio
c) Bottom Upper Ratio
d) Bottom Up Ratio
Answer: a
Clarification: The term BUR in extrusion and calendering of thermoplastics refers to Blow Up Ratio. It is the ratio of bubble diameter to die diameter. BUR for most blown films in packaging generally lies between 2:1 and 4:1.

8. Flexibility of plastic packaging films increases with increasing density.
a) True
b) False
Answer: b
Clarification: The statement is false. Flexibility of packaging films increases with decreasing density. As the density increases, the forces amongst the monomers increases and the rigidity increases. Hence, flexibility decreases.

9. ________ is a process which combines layers of two or more plastics together at the point of extrusion.
a) Lamination
b) Plating
c) Co-extrusion
d) Calendering
Answer: c
Clarification: Co-extrusion is a process which combines layers of two or more plastics together at the point of extrusion. Lamination is the process of packaging via combination of two or more materials by a solvent, adhesive or heat. Calendering is a complementary process to film and sheet extrusion, which involves the formation of continuous sheets of controlled thickness by passing plastic materials through rollers. Plating is the process of coating any surface (especially metal) by other metal, mostly by electrochemical cell.

10. Co-extrusion uses adhesives for binding between two layers.
a) True
b) False
Answer: b
Clarification: The statement is false. Co-extrusion doesn’t use adhesives for binding between two layers. Co-extrusion uses solely heat for binding different layers of plastics. Lamination used adhesives for binding between two layers. Hence, co-extruded films are generally thicker than laminated films.

Food Packaging Technology Multiple Choice Questions & Answers (MCQs) on “Intelligent Packaging Systems”.

1. Intelligent packing techniques can also serve as freshness indicators.
a) True
b) False
Answer: a
Clarification: The given statement is true. Intelligent packing can serve as freshness indicator. It can be divided into external and internal indicator on basis of their use. External indicators are those which are attached outside the package. E.g. Time-Temperature & Microbial growth Indicator. Internal indicators are those which are placed inside the package, either to the head space of the package or attached into the lid. Eg. Oxygen Indicators, Carbon dioxide Indicators, Microbial Growth Indicators, Pathogen Indicators.

2. Which of the following is a Time-Temperature Indicator (TTI)?
a) Life lines fresh check
b) Radiofrequency identification
c) Electronic nose
d) Ultrasonic indicator
Answer: a
Clarification: Line lines fresh check is a Time-Temperature Indicator (TTI). It is an external indicator, placed outside the food packet. It is generally used in food stored under chilled & frozen conditions. Lifelines’Fresh Check indicators are – color-changing, self-adhesive labels which respond to cumulative exposure to temperature.

3. Which of the following TTI is based on enzymatic lipase color change?
a) Electronic nose
b) 3M Monitor Mark
c) LifeLines Fresh-Check
d) Vitsab Single Dot Label (TTI)
Answer: d
Clarification: Vitsab Single Dot Label (TTI) is based on enzymatic lipase color change. It is based on the principle of enzymatic hydrolysis of a lipid substrate (e.g. tricaproin) causes acid release (e.g. caproic acid) & the pH drop is translated in a color change of pH indicator to dark yellow.

4. Which of the following TTI is based on dye diffusion?
a) Electronic nose
b) 3M Monitor Mark
c) LifeLines Fresh-Check
d) Vitsab Single Dot Label (TTI)
Answer: b
Clarification: 3M Monitor Mark is based on dye diffusion. A visco-elastic material migrates into a diffusely light reflective porous matrix at a temperature dependent rate. This causes a progressive change of the light transmissivity of the porous matrix & provides a visual response. Response of indicator is the blue dye ester diffusing along a wick. The useful range of temperature & response life of the TTI are determined by type of ester & the concentration at the origin.

5. Which of the following TTI is based on polymerization reaction?
a) 3M Monitor Mark
b) Electronic nose
c) Vitsab Single Dot Label (TTI)
d) LifeLines Fresh-Check
Answer: d
Clarification: LifeLines Fresh-Check is based on polymerization. It is based on the property of distributed di-acetylene crystals to polymerize through a lattice-controlled solid state reaction proceeding via 1,4 addition polymerization & resulting in high color polymer.

6. Which of the following is an optical chemical sensing method of freshness indication in intelligent packaging?
a) RFID
b) Electronic nose
c) Vitsab Single Dot Label (TTI)
d) 3M Monitor Mark
Answer: b
Clarification: Electronic nose is a simple optical chemical sensing method (colorimetric nose) that utilises the color change taking place in an array of metalloporphyrin dyes upon ligand binding. The liganding vapors (alcohols, amines, ethers, phospines, thiols, halocarbons & ketons) can be visually identified. It is an internal indicator.

7. RFID is used for intelligent packaging in storage and distribution.
a) True
b) False
Answer: a
Clarification: The given statement is true. RFID: Radio Frequency Identification is a non contact, wireless, data communication form where tags of some material, usually embedded with the IC chip, are programmed with unique information & attach to object for identification & tracking. As tagged items pass by readers, the data from the tags is decoded & transfer to the host computer for processing.

8. Carbon dioxide indicators are based on pH dyes.
a) True
b) False
Answer: b
Clarification: The given statement is false. Carbon dioxide indicators are based on chemicals. It gives information about storage conditions and package leak. It is most commonly used in modified or controlled atmosphere food packaging.

9. Which of the following is not an internal indicator?
a) Oxygen indicator
b) Pathogen indicator
c) Microbial growth indicator
d) Time-Temperature indicator
Answer: d
Clarification: Time-Temperature indicator is not an internal indicator. The principle/reagents used are- mechanical, chemical and enzymatic. It gives information about storage conditions. Its application is in food stored under chilled & frozen conditions.

10. Which of the following is based on immuno-chemical methods of freshness indicator?
a) Pathogen Indicators
b) Microbial growth indicator
c) Oxygen indicator
d) Carbon dioxide indicator
Answer: a
Clarification: Pathogen Indicators use various chemical & immuno-chemical methods reacting with toxins. It gives information about specific pathogenic bacteria such as Escherichia Coli O157. It is most commonly used in perishable foods such as meat, fish & poultry.

11. Microbial growth indicator is same as pathogenic indicator.
a) True
b) False
Answer: b
Clarification: The given statement is false. Microbial growth indicator is the one which indicates the first order kinetic growth of a spoilage microorganism. It uses pH dyes and all dyes reacting with certain metabolites (volatiles or non volatiles). Whereas, pathogenic indicator is the one which indicates the presence of toxins producing pathogenic microorganisms which may or may not cause spoilage, but can cause disease.

Food Packaging Technology Multiple Choice Questions & Answers (MCQs) on “Coating and Laminating in Thermoplastics”.

1. A single laminate layer is thicker than _____
a) 15 μm
b) 6 μm
c) 1 μm
d) 10 μm
Answer:b
Clarification: A single laminate layer is thicker than 6µm. A laminate is made up of two or more layers which can be plastic or non-plastic. But at least one layer must be a plastic. All layers to make a laminate must be thicker than 6 μm. However, there is no upper limit for this.

2. Coating is the bonding of two or more layers.
a) False
b) True
Answer: a
Clarification: The above statement is false. Coating is the process of applying one or more layers of a fluid or melt to the surface of a material, while laminating is the bonding of two or more webs/layers.

3. Materials other than a thermoplastic can be used in a laminate.
a) True
b) False
Answer: a
Clarification: The given statement is true. Materials other than a thermoplastic can be used in a laminate. A laminate is defined as any combination of distinctly different plastic film materials or plastic plus non plastic materials (typically paper and aluminium foil).

4. In the process of surface treatment before lamination or coating, the surface energy is ______
a) Constant
b) Decreased 10 fold
c) Increased
d) Decreased
Answer: c
Clarification: In the process of surface treatment before lamination or coating, the surface energy is increased. This is done to improve wet-out and adhesion of coatings, inks and adhesives used. Improved wet-out maximises the contact area and attractive forces between the films.

5. Which of the following treatments increases the surface energy by using electricity?
a) Chemical Treatment
b) Priming
c) Flame Treatment
d) Corona Treatment
Answer: d
Clarification: Corona treatment involves the application of a high voltage (10–40 kV) low frequency (10–20 kHz) discharge across a fixed air gap between an electrode and an earthed conductive roller which carries the film. The corona treatment cleans, oxidizes and activates the surface by converting it from a nonpolar to a polar state by bombarding it with ozone, O₂ and free radicals of O₂. This increases the surface energy and results in the substrate surface being more compatible with a freshly oxidized thermoplastic surface, thus promoting adhesion between the two.

6. For Flame Treatment prior to laminating and coating, the temperature time combination is _____
a) 2000-4000°C, 5s
b) 1000-2800°C, 1s
c) 3000-5000°C,10s
d) 1000-2800°C, 15s
Answer: b
Clarification: For Flame Treatment prior to laminating and coating, the temperature time combination is 1000-2800°C, 1s. If the temperature or time increases, the film degrades and becomes weak. If the temperature or time is less than required, the film would have a lower surface energy than required.

7. Optimum primer weight for priming films is defined in _____
a) mg/m²
b) μg/m²
c) mg/cm²
d) mg/mm²
Answer: a
Clarification: Optimum primer weight for priming films is defined in mg/m². The quantity of primer is a critical aspect because thicker primer results in lesser cohesive forces and hence loss of adhesiveness. Thinner primer wouldn’t result in required adhesion.

8. Which of the following processes is done to remove surface contaminants?
a) Priming
b) Chemical Treatment
c) Corona Treatment
d) Flame Treatment
Answer: b
Clarification: Chemical treatment is an essential step in surface treatment to remove surface contaminants. Rest of the treatments- priming, corona treatment and flame treatment are mainly done for increasing surface energy. Chemical treatment has mainly three steps- cleaning, etching and rinsing.

9. Which of the following plastics is used in the lamination of paperboards?
a) LDPE
b) PS
c) PVC
d) HDPE
Answer: a
Clarification: LDPE is used in the lamination of paperboards. Compares to other thermoplastics, LDPE- Low Density Polyethylene offers a greater strength, seal integrity and resistance to cracking and flaking off. It also provides a greater resistance to moisture and has greater flexibility.

10. Which of the following materials is used for solventless laminating?
a) Sodium silicate
b) Polyester isocyanate
c) Rubber latex
d) Dextrin
Answer: b
Clarification: Polyester isocyanate is used for solventless laminating. Solventless laminating is the process of bonding together two webs by curing in absence of solvents. Polyester isocyanates is used for curing the laminate.

11. Which of the following lamination methods doesn’t require an adhesive for lamination?
a) Dry bonding lamination
b) Solventless lamination
c) Extrusion lamination
d) Wet bonding lamination
Answer: c
Clarification: Extrusion lamination doesn’t require an adhesive for lamination. It causes adhesion by heat and pressure during the process of extrusion. Dry and wet bonding lamination used aqueous or solvent based adhesives. Solventless lamination uses a curing agent for adhesion.

12. ASTM stands for _____
a) American Society for Testing Machines
b) American Society for Tempering Machines
c) American Society for Testing and Measurements
d) American Society for Testing Materials
Answer: d
Clarification: ASTM stands for American Society for Testing Materials. ASTM is an international standards organisation which sets up standards for various miscellaneous materials including metals and plastics.

13. Lacquering and lamination are the same terms.
a) True
b) False
Answer: b
Clarification: The given statement is false. Lacquering is a term used for coatings on can, mainly to provide it a resistance against discoloration and corrosion. Whereas, lamination is a term used for combination of two or more materials into a single homogeneous packaging webs using adhesive, solvent or heat.

14. Which of the following materials is the outermost lamination layer in tetrapacks?
a) Polyester
b) Polypropylene
c) Polyethylene
d) Polystyrene
Answer: a
Clarification: Polyester is the outermost lamination layer in tetrapacks. Polyester provides strength to the tetrapack. It also acts as an excellent printable surface. Polypropylene is the innermost layer, the food contact layer. Polyethylene and polystyrene is not used in tetrapacks.

15. Polymers used for packaging films must have a surface energy – _______
a) 5-25 mNm^-1
b) 29-45 mNm^-1
c) 45-55 mNm^-1
d) 10-25 mNm^-1
Answer: b
Clarification: Polymers used for packaging films must have a surface energy- 29-45 mNm^-1. The standard is set by ASTM. Also, the surface energy of the substrate should be 7-10 mNm^-1 higher than the surface tension of coating being applied.

Food Packaging Technology Quiz on “Glass as Packaging Material”.

1. Glass is a super cooled liquid.
a) True
b) False
Answer: a
Clarification: The given statement is true. Glass has been defined by the American Society for Testing and Materials (ASTM) as “an amorphous, inorganic product of fusion that has been cooled to a rigid condition without crystallizing”.

2. The main component of glass is _____
a) silica
b) quartz
c) sand
d) flint
Answer: a
Clarification: The main component of glass is silica. The principal ingredient of glass is silica derived from sand, flint or quartz. Silica can be melted at very high temperatures (l723°C) to form fused silica glass which, because it has a very high melting point, is used for specialized applications including some laboratory glass.

3. The glass surface is subject to corrosion due to the presence of ______
a) magnesium
b) potassium
c) sodium
d) calcium
Answer: c
Clarification: The glass surface is subject to corrosion due to the presence of sodium. The glass surface is subject to three forms of “corrosion”: etching, leaching and weathering, as a consequence of the sodium in glass being loosely combined in the silica matrix.

4. _______ is characterized by alkaline attack in glass.
a) Leaching
b) Etching
c) Scaling
d) Surface bloom
Answer: b
Clarification: Etching is characterized by alkaline attack, which slowly destroys the silica network, releasing other glass components. It is a form of corrosion in glass.

5. What is the basic structural unit of silica in glass?
a) Tetrahedron
b) Octahedron
c) Square bipyramidal
d) Trigonal bipyramidal
Answer: a
Clarification: The basic structural unit is the silicon oxygen tetrahedron in which a silicon atom is tetrahedrally coordinated to four surrounding oxygen atoms. This amorphous structure, without slip planes formed by crystal boundaries that might allow deformation, is responsible for the stiffness and brittleness of glass.

6. ________ is characterized by acid attack in glass.
a) Weathering
b) Scaling
c) Leaching
d) Surface bloom
Answer: c
Clarification: Leaching is characterized by acid attack in which hydrogen ions exchange for alkali or other positively charged mobile ions. The remaining glass (principally silica) usually retains its normal integrity.

7. _______ mild form of weathering in glass.
a) Scaling
b) Surface bloom
c) Tempering
d) Leveling
Answer: b
Clarification: A mild form of weathering is commonly known as surface bloom and may occur under extended storage conditions. To save the glass from surface bloom, fluorine gas is generally used.

8. ______ is the part of the bottle that holds the cap or closure.
a) Finish
b) Body
c) Fissure
d) Seal
Answer: a
Clarification: Finish is the part of the bottle that holds the cap or closure, the glass surrounding the opening in the container. It includes thread and neck.

9. _______ of the container is the portion that is made in the body-mold.
a) Head
b) Shoulder
c) Cavity
d) Body
Answer: d
Clarification: Body of the container is the portion that is made in the body-mold. Body lies between the finish and the bottom and is generally the largest part of the container. Shoulder is the part between base of neck and the body.

10. Silica is combined with _______ to increase hardness and durability in glass.
a) boron
b) alumina
c) lead
d) alkali flux
Answer: b
Clarification: Silica is combined with alumina to increase hardness and durability in glass. Glass contains around 1.5%–2% alumina (Al₂O₃).

11. Silica is combined with lead in glass due to which of the following reasons?
a) Reduce the leaching of sodium
b) Hardness and durability
c) Clarity and brilliance
d) Preventing the glass from dissolving in water
Answer: c
Clarification: Silica is combined with lead in glass as lead provides clarity and brilliance to glass. Silica is combined with other raw materials in various proportions for the following reasons-
Alumina increases hardness and durability.
6% boron reduces the leaching of sodium.
Calcium and magnesium carbonates (limestone and dolomite) acts as stabilizers, preventing the glass from dissolving in water.

12. ______ is the spiral groove on the closure.
a) Face
b) Skirt
c) Panel
d) Thread
Answer: d
Clarification: Thread is the spiral groove on the skirt of a continuous thread closure that meshes with the tread on the glass finish. Face is the outside of the cap. Panel is the flat center area in the top of the closure. Skirt is the flat, almost vertical portion on the side of the closure, which serves as the gripping surface and may be smooth, knurled or fluted.

13. Gasket in glass is also known as ________
a) liner
b) face
c) thread
d) reverse
Answer: a
Clarification: Gasket or liner is the actual sealing component of the closure, which makes an intimate contact with the glass finish to form an effective seal. Gaskets are made from rubber or plastisols.

14. Which of the following is main function of lug-type or twist cap?
a) Closures to retain internal pressure
b) Closures to contain and protect contents
c) Closures to maintain vacuum inside container
d) Closures to secure contents inside containe
Answer: c
Clarification: Closures used with food containers can be classified under four chidings. They are-
i. Closures to retain internal pressure – They retain an internal pressure of 200-800 kPa, as found in carbonated drinks and beer. Ex. Crown cork, Roll-on tamper evident aluminum closure
ii. Closures to contain and protect contents – They contain and protect the contents with no internal pressure (Ex. Wine in a bottle). Ex. Bark cork
iii. Closures to maintain vacuum inside container – They maintain a vacuum inside glass containers that typically contain heat-processed food. Ex. Lug-type or twist cap, Press-on twist –off cap, Pry-off (side seal) cap
iv. Closures to secure contents inside container – They are to secure the contents inside the glass container (Ex. Peanut butter).

15. Which of the following adds rigidity to the cap in glass closure?
a) Curl
b) Face
c) Lug
d) Reverse
Answer: a
Clarification: Curl adds rigidity to the cap in glass closure. It also protects the cut edge of the metal. Curl is the round or rolled portion at the bottom of the skirt. Lug is a horizontal inward protrusion from the curl that is seated under the thread on the glass finish and holds the cap in position. Face is the outside of the cap. Reverse is the inside of the cap.

Food Packaging Technology for Quizzes,