MFT-004>>Block-1>>Unit-1>>
Unit-1:Introduction
MFT-004>>Block-1>>Unit-2>>
Unit-2:Packaging Materials and Properties of Materials
MFT-004>>Block-1>>Unit-3>>
Unit-3:Recent Trends in Food Packaging
3.0 : Objective
3.1 : Introduction
3.2 : Vacuum Package
3.3 : Gas Packaging
3.3.1 : Oxygen
3.3.2 : Carbon dioxide
3.3.3 : Nitrogen
3.4 : Aseptic packaging
3.5 : Retort packaging
3.6 : Active Packaging
3.6.1 : Ethylene scavengers
3.6.2 : Carbon dioxide scavengers and emitters
3.6.3 : Humidity regulators
3.6.4 : Oxygen scavengers
3.6.5 : Antimicrobial packaging
3.6.6 : Breathing films
3.7 : Biodegradable Packaging
3.8 : Let us sum up
3.9 : key words
3.10 : Answers to check your progress exercises
3.11 : Some useful books
3.0 : Objective
After reading this unit, you should be able to: Explain
different types of packaging systems Understand the importance of
packaging systems Define functions of packages Explain the
relationship between food properties and properties of packaging
materials Design and develop packages for different foods
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3.1 : Introduction
You have studied packaging requirement and their selection for
different food products. When you go to super markets you will see
newer and newer packages on the shelf quite often. The shifts in
packaging trends are due to consumers demand for convenience,
information, attractive display, address one or more specific needs
etc. In this unit you will study recent trends in food
packaging.Modern food packaging innovations have made it possible
to keep the food fresh for a much longer time, without changing the
taste or aroma. The goal of developing food packaging is the
achievement of a more ideal match of the properties of the package
to the requirements of the food. Hence it addresses one or more
specific needs of the food without necessarily having any impact on
other food properties. Flavour and odour absorbers like films and
sachets have been introduced to reduce the transfer of aroma or
flavour between components. This helps keeping food items fresh and
natural for a long times. Various industries have introduced
specific technologies suiting their special food type.Drip
absorbing pads have been introduced for moisture control and oxygen
removal systems have been used to keep egg fresh for a longer
period of time in poultry industry. Digital technology has been
introduced to look into the freshness of food items. Ripeness
indicators have been designed recently to monitor and communicate
information about food quality.Intelligent or smart packaging is
designed to monitor and communicate information about food quality.
Examples include ripeness indicators and radio frequency
identification. These smart devices may be incorporated in package
materials, attached to the inside or outside of a package, or
sometimes the product itself. These smart devices can be
incorporated on the food item itself. Packaging developments such
as packages incorporating antimicrobials and oxygen scavengers
established new precedents for prolonging shelf life and protecting
food from environmental influences. Nevertheless, omnipresent
global trends such as increased industrial processing of food,
greater importation and exportation of food products, and less time
for preparation of fresh foods compel the food and beverage
packaging industry to investigate newer, more advanced packaging
solutions. It is said that nano technology will produce the most
remarkable new food packaging concepts. Work has already begun in
the field of active and intelligent packaging, pathogen detection
and creating good barriers between various food materials.Thermal
processing is one of the conventional preservation methods which
assures processed foods to be safe and shelf stable. Thermal
processing of foods in cans and bottles is a well known technology
which is a common operation in food industry. In this the product
is hermetically sealed in a container and heat processed in a
retort for required time to arrive at commercial sterility. It is
also known as in container sterilization. Now-a-day, it has even
extended for plastic based semi rigid and flexible containers known
as retort trays and retort pouches respectively. Retort trays are
semi rigid containers with a high barrier core layer and retort
pouches are flexible packages made of multilayer films with or
without aluminium foil. Aluminium foil serves as the barrier layer
and is responsible for longer shelf life of over one year for the
product. Silicate SiO2layer is also being used as an alternate to
aluminium layer as it gives clear pouches and also has the
advantage of being micro ovenable. The most important feature of
these containers is that they are made of plastics amenable for
processing in retorts at temperatures of about 121C. All new
innovations in food packaging have some element of "green"
sustainable with the criteria of 1) It has to be healthy safe and
beneficial for communities and individuals throughout its
lifecycle. 2) It meets market criteria for performance and cost. 3)
It is sourced, manufactured, transported and recycled using
renewable energy. 4) It maximizes the use of renewable or recycled
source materials. 5) It is manufactured using clean production
technologies and best practices. 6) It is made from materials
healthy in all probable end-of-life scenarios. 7) It is designed to
optimize materials and energy. 8) It is recovered effectively and
used in biological and/or industrial cradle to cradle cycles.These
are among the many developments emerging from research labs
worldwide where food scientists, materials specialists and others
continually attempt to improve current packaging materials and
develop new ones with optimal barrier properties. Like food
products themselves, packaging materials are constantly evolving to
meet the latest demands of the marketplace. Companies have a
significant interest in improving their food products. New
packaging films that offer optimal barrier properties undoubtedly
will help companies meet the challenge of keeping products fresh
and extending their shelf life.
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3.2 : Vacuum Package
In the retail shops you will find products like dry foods such
as cereals, nuts, cured meats, cheese, smoked fish, coffee etc are
packed in vacuum. In this section we will find out why they are
vacuum packed.
Fig 3.1 Vacuum packaged food productsVacuum packaging refers to
packaging in containers (rigid or flexible), from which
substantially all air has been removed prior to final sealing of
the container. This method of packaging is actually a form of
Modified Atmosphere since normal room air is removed from the
package. Vacuum packaging helps in extending shelf life; in
controlling oxidative rancidity; preventing the growth of normal
spoilage bacteria; in suspending Aerobic organisms such as
Pseudomonas and favouring lactic-acid bacteria. The latter can grow
to high numbers without causing spoilage. Reduces moisture loss and
freezer burn. Prevents movement of water out of the product into
the surrounding headspace. Prevents loss of moisture at product
surface and eliminates freezer burn. Requires minimal storage space
Package is drawn tight around product taking up minimal space.
Leakers are easily detected A small puncture or pinhole in a vacuum
pack is easy to detect by looking for loose packages. This
technique has been shown to help maintain the quality of various
frozen products including pizza, seafood, beef and pork.
There are two forms of vacuum packaging, depending on the
rigidity of the package. The first form of vacuum packaging
involves a rigid package (e.g., glass jar) or a semi-rigid package
(e.g., plastic container) in which most of the air is evacuated,
but a headspace still remains in the package. The removal of air
typically reduces the oxygen level in the headspace to as low as
1%, which significantly helps to reduce the problem of oxidation.
However, frost formation and freezer burn are still problematic
since the headspace exists.
The second form of vacuum packaging involves a flexible package
(e.g., a plastic pouch) in which not only the oxygen is removed but
also the headspace is eliminated. Thus both oxidation and frost
formation are controlled. This form is also known as vacuum skin
packaging, since the food is tightly wrapped by the package. The
mechanical stress created by the vacuum also helps to remove air
pockets inside the product. This technique has been widely used to
package frozen meat and seafood products including meat balls, clam
strips, lobster tails, salmon, and farmed rainbow trout.
Several types of materials are used for vacuum skin packaging,
such as a blend of Surlyn ionomer resin with low density
polyethylene (LDPE) and ethylene-vinyl acetate (EVA). Vacuum
packaging requires the use of gas barrier packaging materials;
otherwise, the vacuum cannot be maintained for a prolonged period
of time.
Vacuum packaging, and reduced oxygen packaging, is an excellent
way of preserving frozen food quality and safety. The exclusion of
oxygen from the microenvironment surrounding the food has benefits
to prevent the growth of aerobic microorganisms and also minimizes
the effects of detrimental oxidative biochemical reactions, which
would normally set a limit on the achievable quality shelf-life of
the food. Vacuum packaging is also an excellent means of minimizing
surface moisture loss, both in terms of dehydration during freezing
and drip loss during thawing. The technology is also beneficial
from a processing perspective, as the skin-tight package on the
food readily allows heat transfer from the food to the freezing
medium. This means that foods can be packaged prior to the freezing
operation, which makes the essential requirement of good hygiene
practice a little easier for the food manufacturer.
Fig 3.2 Vacuum Chamber SealersExternal Sealers
External vacuum sealers involve a bag being attached to the
vacuum-sealing machine externally. The machine will remove the air
and seal the bag, which is all done outside the machine.
Chamber Sealers
Chamber sealers require the entire product to be placed within
the machine. Like external sealers, a plastic bag is typically used
for packaging. Once the product is placed in the machine, the lid
is closed and air is removed. Once the air is removed, the bag is
sealed and the atmosphere within the chamber is returned back to
normal. The lid is then opened and the product removed. Chamber
sealers are typically used for higher-volume packaging.
We have studied the vacuum packed products. Now we will see some
of the products like potato chips are packed with gases called gas
packaging.
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3.3 : Gas Packaging
Gas packaging can be defined as the alteration of the
proportional volumes of the gases which comprise a normal
atmosphere. This type of packaging generally falls into two
categories. The most commonly used gases for the packaging are CO2,
N2and O2. According to EU legislation, foods packaged in modified
atmospheres must be labelled with a phrase like Packaged in a
protective atmosphere. Gases for the packaging of meat are seldom
used alone but in mixtures, which vary according to the
application.Materials used for modified atmosphere packaging are a
combination of different substrates. The materials can be as simple
as two-ply laminations or multi-layer coextrusions, incorporating
EVOH as a high barrier substrate.
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3.3.1 : Oxygen
One of the major functions of oxygen is to maintain the red
pigment, myoglobin in the oxymyoglobin state that is responsible
for the bright red colour associated with freshness. Oxygen
pressure levels over 240 mm are thought to greatly increase and
extend the fresh appearance of meats.
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3.3.2 : Carbon dioxide
Carbon dioxide is a known inhibitor of microbial growth.
Gram-negative spoilage flora of refrigerated meat is especially
sensitive to CO2while lactic acid bacteria are less affected. The
inhibitory effects of CO2have been attributed to alteration of the
bacterial cells permeability, pH changes and enzymatic inhibition.
CO2helps to increase the lag phase and generation time, which
delays the overall increase of bacterial populations. Factors such
as initial bacterial load, time of application, storage temperature
and gas concentration will affect the desired end result. The
inhibitory efficiency of CO2is increased at lower temperatures.
This is thought to be due to the fact that the solubility of gases
is much higher at lower temperatures; the CO2concentration in the
medium will increase as the temperature is lowered.Carbon dioxide
reacts with water to form carbonic acid and can actually dissolve
in food products. As the gas dissolves in the water the quantity of
gas within the package diminishes and a partial vacuum is
generated. This may bring about the collapse of the pack.Carbon
dioxide by itself already been recognized for a significant effect
of inhibiting pathogens, but concentrations over 30 percent or 40
percent usually result in discoloration of fresh meat. But in
combination with carbon monoxide, the colour is greatly improved.
With cooked, cured, processed products, the higher levels of carbon
dioxide are acceptable. It doesnt discolour those products such as
ground meat or pork chops.
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3.3.3 : Nitrogen
Nitrogen is an inert gas and is abundantly available at
relatively low cost, has neither colour nor odour and is chemically
unreactive. It has a low solubility in both water and fat. In
modified atmospheres nitrogen is used to displace oxygen in order
to delay aerobic spoilage and oxidative deterioration. Another role
of nitrogen is to act as a filler gas so as to prevent pack
collapse. Nitrogen packaging is common for foods like potato chips,
snack foods, fruits and vegetables, and many meat and seafood
items.
Fig 3.3 Vacuum and Gas packaging machineCheck Your Progress
Exercise 1
Note: a) Use the space below for your answer b) Compare your
answer with those given at end of the unit.1. What is vacuum
packaging?...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
2. How is shelf life extended under
vacuum?.......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
3. What are advantages of Vacuum
Packaging?...........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
4. What is nitrogen or inert gas
packing?................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
5. Do you have to use special pouches for vacuum/gas
packaging?................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
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3.4 : Aseptic packaging
Aseptic packaging can be defined as the filling of a
commercially sterile product into a sterile container under aseptic
conditions and hermetically sealing the containers so that
reinfection is prevented. This results in a product, which is
shelf-stable at ambient conditions. The term aseptic is derived
from the Greek word septicos which means the absence of
putrefactive micro-organisms. In practice, generally there are two
specific fields of application of aseptic packaging technology:
Packaging of pre-sterilised and sterile products. Examples are milk
and dairy products, puddings, desserts, fruit and vegetable juices,
soups, sauces, and products with particulates. Packaging of
non-sterile product to avoid infection by micro-organisms. Examples
of this application include fermented dairy products like
yoghurt.Aseptic packaging technology is fundamentally different
from that of conventional food processing by canning. In canning,
the process begins with treating the food prior to filling. Initial
operations inactivate enzymes so that these will not degrade the
product during processing. The package is cleaned, and the product
is introduced into the package, usually hot. Generally, air that
can cause oxidative damage is removed from the interior. The
package is hermetically sealed and then subjected to heating. The
package must be able to withstand heat up to about 100C for high
acid products and up to 127C for low acid products, which must
receive added heat to destroy heat-resistant microbial spores.
Packages containing low-acid (above pH 4.5) food must withstand
pressure as well. Although conventional canning renders food
products commercially sterile, the nutritional contents and the
organoleptic properties of the food generally suffer in the
processing. Moreover, tinplate containers are heavy in weight,
prone to rusting and are of high cost.
The three main advantages of using aseptic packaging technology
are: Packaging materials, which are unsuitable for in-package
sterilisation can be used. Therefore, light weight materials
consuming less space offering convenient features and with low cost
such as paper and flexible and semi-rigid plastic materials can be
used gainfully. Sterilisation process of high-temperature-short
time (HTST) for aseptic packaging is thermally efficient and
generally gives rise to products of high quality and nutritive
value compared to those processed at lower temperatures for longer
time. Extension of shelf-life of products at normal temperatures by
packing them aseptically.Besides the features mentioned above,
additional advantages are that the HTST process utilises less
energy, as part of the process-heat is recovered through the heat
exchangers and the aseptic process is a modern continuous flow
process needing fewer operators. Figure shows schematic
representation of aseptic packaging process. Different methods
based on physical process, chemical sterilisers and radiations are
used for sterilisation of packaging materials.
Fig 3.4: Schematic diagram of Aseptic packaging
processFunctional requirements1. High impermeability to water
vapour, zero WVTR for prolonged storage. 2. Very low permeability
to gases especially oxygen since its interaction leads to chemical
and biological deterioration.3. Aroma barrier property to preserve
odours and freedom from external taints.4. Inertness with the
product packed, sterilizing treatments, imparted-heat, chemicals or
radiations.5. Perfect package and closure integrity.6. Capacity to
form well on operating machinery.7. Provide user convenience for
unit and bulk packages.8. Thermal stability for both low and high
temperature.9. Sufficiently robust to withstand rough treatment
likely to occur during handling and transportation.10. Meet all
regulatory specifications.Aseptic packaging forms: Aseptically
processed foods are packed in varieties of packaging materials and
forms comprising flexible, semi rigid and rigid containers. Their
structure, form and application are as follows.
Flexible pouches and bags: Flat or Stand up pouches like PET/PE,
met PET/PE, PET/Al foil/PE and some co-extruded film structures can
be used for this. The shelf lives of aseptically processed foods
are given in Table 5.
Cartons in aseptic packaging: Different types of cartons
gable-top, tetrahedron and brick shape are employed for aseptic
packaging. The tetrahedral shape has the advantage of minimum ratio
of area to volume and employed for liquid food. Brick cartons are
very popular as they facilitate easy distribution. The cartons are
essentially made of PE/paper/PE/Al foil/PE with slight differences
among manufacturers. Especially for aseptic juice applications, the
inner most layer is PE-Ionomer co-extruded web as this eliminates
PE de-lamination from the foil. A typical six layer laminate
construction used in aseptic packaging is 16 m coating/ 240 gsm
paper board/ 16 m PE/ 9-10 m Al foil/ 11 m Ionomer and 38 m PE. The
outermost PE layer provides water vapour barrier property, paper
board provides stiffness, ease of formation on automatic machines
and printability. 9-10 m Al foils afford gas and water vapour
barrier property, odour proofness and light protection. Ionomer
eliminate seal failures and leakers and resist cracking at score
lines. However it has been shown that oxygen transmission rate at
the scored area would be 40-50 times higher than flat area. To
eliminate the risk of contamination from the base of carton, all
edges are protected.
Fig 3.5 Composition of Tetra packs Aseptic Carton.Bag in the box
system: Bag in the box is high barrier multilayer bag contained in
a shipping container of CFB or wooden box or metal drum. The
capacity of the bag ranges between 5 liters institutional use to
250 liters (60 gallons) for industrial market (Paine 1987). Even
1135 liters (300 gallon) bulk containers are also available.
Generally these bags are made of met PET/PE or PA/PE having 4 side
seals of width 5-10 mm. Inclusion of a single web of inner loose
liner of LLDPE provides added physical strength. High barrier Al
foil laminates with PET or PA / Al foil / PE / LDPE / LLDPE are
also being used for aseptic bags. The most important factor in bag
design is the spout. In normal use the bag has a welded fitment
which contains a rigid plastic spout which is fitted with a screw
cap or pressed fit cap and some with spigots for easy dispensing.
There are different types of construction of spouts with ability to
maintain aseptic conditions.Bag in drum system: These are bulk
metal containers used for aseptic bags. They are normally 247.5 lt
electrolytically tin plated containers. The body and the components
are made from electroplated 18 gauge steel with 6-10 times more tin
coating than the normal tin plate cans. The drum is normally coated
with a suitable food lacquer and can withstand a vacuum of 27.The
aseptic packaging is very well accepted in food service
applications worldwide as a safe and high-quality packaging option.
Aseptic processing sterilizes food products by destroying the
harmful bacteria and pathogenic micro-organisms through a tightly
controlled thermal process and combines the sterile product with
the sterile packaging material in a sterile environment; the end
result is a shelf-stable product requiring no refrigeration. The
use of plastics in the aseptic packaging significantly increases
the non-refrigerated shelflife and availability of many perishable
products. Today, this is readily being used in the innermost
contact layers of the package, thereby protecting the quality of
food.
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3.5 : Retort packaging
Retort is a cooking process that uses heat and pressure to cook
food in its sealed package. Retort Packaging conditions are quite
demanding with temperatures typically ranging from 120C to 130C.
Different retort grade films which are laminated together to
provide the strength, toughness, puncture and burst resistance that
enable flexible retort packaging to withstand the strenuous retort
process.
Fig 3.6 RetortRetort packaging was initially developed using
glass and metal. Consumer convenience, safety concerns and cost
issues served as the genesis for the development of plastic resin
formulations capable of sustaining the challenging retort
temperatures. The magnitude of the development challenge is
proportional to the thermal and pressure history of the package in
the retort. These attributes of the process are governed by the
target Fo value required to achieve sterilization.
A retortable pouch is a multi-layered lamination structure
designed to withstand extreme conditions, including cooking,
freezing, dropping, and flexing. It can also be heated and
sterilized, thereby providing for long term storage. To properly
retort a pouch, temperatures can reach up to 275 F for up to 90
minutes. Many new pouches feature a clear, see-through lamination
structure and, to provide added convenience, some new retort
pouches feature re-closable zippers or spouts. Retorted pouches are
often designed to remain stable for up to 60 months.
For many food products, retortable pouches have already replaced
a metal can. Two prominent examples include tuna fish and moist pet
food. These products are readily found today on store shelves in
pouch form. Also found on store shelves in retortable packages are:
seafood, precooked meats, rice, sauces, soups, stews, and many
others.
Retort pouch packaging has superior barrier and printing
qualities and can be supplied as stand-up, flat or in roll form.
Flexible retort packaging offer a variety of additional benefits
over rigid packaging to both retailers and consumers that include :
Superior taste due to reduced retort time. Extended shelf life in
retort packaging. Reduced storage space in retort packaging, both
in warehouse and pantries. Reduced transportation costs. Easier and
safer tear-open/disposal consumer experience. Microwave convenience
retort packaging
Retort packaging and packaging are available in two variants one
is aluminium foil laminated and another transparent see through
retort packaging .
Common flexible retort packaging structures include the
following:
PET / FOIL / Nylon / CPP PET / Nylon / FOIL / CPP PET-SiOX or
AlOX / Nylon / CPP
Due to retort packaging have their thinner dimensions; it takes
less time to cook food in a flexible retort packaging than in other
forms of rigid packaging such as cans and jars. This reduced retort
time results in foods that have superior taste in retort
pouches.
Fig 3.7 Retort pouchesSuitable semi rigid containers for thermal
processing are
1. Injection moulded multiple pocket plastic trays of
construction PP/ PVDC(or EVOH)/ PP2. Al Foil based trays made of
Body- Epoxy resin / 100-150 m Al Foil / 50 m PP3. Lid - Epoxy resin
/ 50- 100 m Al Foil / 50 m PP
Fig 3.8 High barrier polypropylene retort tray
Fig 3.9 Lid material for trayCheck Your Progress Exercise 2
Note: a) Use the space below for your answer b) Compare your
answer with those given at end of the unit.
1. What are the benefits of aseptic packaging to the
consumer?............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................2.
What is aseptic
packaging?..............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
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3.6 : Active Packaging
Active packaging is an emerging and exciting area of food
technology which can confer many preservation benefits on a wide
range of foods. The aim of active packaging is to match the
properties of the package to the more critical requirements of the
food. Adoption of some of these methods will require changes in
attitude to packaging and a willingness to address regulatory
issues where chemical effects are used. Application of these and
other emerging technologies offers the prospect of greater
satisfaction in India as these are relatively new concepts, and
that we are maximising the benefits from some of our traditional
agricultural industries.
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3.6.1 : Ethylene scavengers
Ethylene (C2H4) acts as a plant hormone that has different
physiological effects on fresh fruit and vegetables. It accelerates
respiration, leading to maturity and senescence, and also softening
and ripening of many kinds of fruit. Furthermore, ethylene
accumulation can cause yellowing of green vegetables and may be
responsible for a number of specific postharvest disorders in fresh
fruits and vegetables. Although some effects of ethylene are
positive such as degreening of citrus fruit, ethylene is often
detrimental to the quality and shelf life of fruits and vegetables.
To prolong shelf life and maintain an acceptable visual and
organoleptic quality, accumulation of ethylene in the packaging
should be avoided. Most of these absorbers are supplied as sachets
or integrated into films. Potassium permanganate (KMnO4), oxidizes
ethylene to acetate and ethanol. In this process, colour changes
from purple to brown indicating the remaining C2H4scavenging
capacity. Products based on KMnO4cannot be integrated into
food-contact materials, but are only supplied in the form of
sachets because KMnO4is toxic and has a purple colour. Typically,
such products contain 4 to 6% KMnO4on an inert substrate with a
large surface area such as perlite, alumina, silica gel,
vermiculite, activated carbon or celite. CFTRI Mysore has developed
KMnO4and activated brick power based ethylene scavengers in sachet
for storage and transportation and refill for refrigerators
respectively. Rengo Co. (Japan) developed `Green Pack', a sachet of
KMnO4embedded in silica. The silica adsorbs the ethylene and the
permanganate oxidizes it to acetate and ethanol. The technology of
C2H4scrubbing has also been transferred to household refrigerators
in USA. Systems containing a zeolite coated with KMnO4are now
available and are meant to be used in consumer refrigerators e.g.
Mrs Green's Extra Life cartridges from Dennis Green (USA) and
Fridge Friend TM sachets from Ethylene Control.
Furthermore, the adsorbing capacity is often lost when
incorporating these minerals into a polymer matrix. Commercially
available examples of these mineral containing materials are the
Orega plastic film (Cho Yang Heung San Co., Korea), Evert-Fresh
(Evert-Fresh Co., USA), Peakfresh TM (Peakfresh Products,
Australia), BO film (Odja Shoji Co., Japan) and ProfreshTM Europe).
PeakfreshTM is a mineral impregnated film that is FDA approved and
complies with current EU directives. C2H4scavengers are not yet
very successful, probably because of insufficient adsorbing
capacity. A large proportion of the fresh fruits and vegetables
harvested each year are lost due to fungal contamination and
physiological damage. The C2H4adsorbing packaging concepts could
possibly contribute to an increase in the internal trade as well as
export of fresh produce.
Fig 3.10 Ethylene scavenger
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3.6.2 : Carbon dioxide scavengers and emitters
CO2is formed in some foods due to deterioration and respiration
reactions. The produced CO2has to be removed from the package to
avoid food deterioration and/or package destruction. CO2absorbers
might therefore be useful. The active compound Ca(OH)2of FreshLock
reacts at sufficiently high humidity with the CO2to produce CaCO3.
A CO2absorbent sachet includes porous envelope containing CaO and a
hydrating agent such as silica gel on which water is absorbed.In
some cases, however, high CO2levels (10-80%) are desirable for
foods such as meat and poultry because these high levels inhibit
surface microbial growth and thereby extend shelf-life. Fresh meat,
poultry, fish and cheese can benefit from packaging in a high
CO2atmosphere. Removal of O2from a package by use of O2absorbers
creates a partial vacuum which may result in a collapse of flexible
packaging. Also, when a package is flushed with a mixture of gases
including CO2, the CO2dissolves partly in the product and creates a
partial vacuum. In such cases, the simultaneous release of CO2from
inserted sachets which consume O2is desirable. Such systems are
based on either ferrous carbonate or a mixture of ascorbic acid and
sodium bicarbonate. The O2absorbers/CO2generators are mainly used
in products where package volume and package appearance are
critical.
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3.6.3 : Humidity regulators
This approach allows the food packer to reduce the surface
concentration of water in a food by reducing the in-pack relative
humidity. This can be done by placing one or more humectants
between two layers of a plastic film which is highly permeable to
water vapour. An example of this type of product is "Pitchit"
manufactured by Showa Denko in Japan. The film duplex is described
as containing an alcohol, as propylene glycol and a carbohydrate,
both of which are humectants. A different approach to humidity
buffering is being developed for use in the distribution of
horticultural produce which is normally distributed in fibreboard
cartons, usually with a polyethylene liner or made from very
expensive waxed fibreboard without a liner. A recent development
has been the water-barrier coating of the inside of fibreboard
cartons to allow moist produce to be placed directly into the
carton. Besides the introduction of liquid water with the produce,
packing into closed spaces allows the build-up of water vapour.
Since temperature cycling is very difficult to avoid during
handling there is every likelihood of condensation and with this
the growth of microorganisms on fruits and vegetables.Two widely
different approaches have been taken to buffering the humidity in
the cartons in order to prevent condensation while not concurrently
causing desiccation of the produce. One is to include microporous
bags or pads of inorganic salts and the other is to line the carton
with a protected layer of a solid polymeric humectant.The most
recent alternative involves the use of the carton as the active
package rather the use of an insert. This approach lends itself to
combination with EMA generation less readily as the humidity is
buffered at the interface with the fibreboard. The designs of
Patterson and Joyce involve a) an integral water vapour barrier
layer on the inner surface of the fibreboard, b) a paper-like
material bonded to the barrier and which acts as a wick, and c) a
layer highly permeable to water vapour (but unwettable) next to the
fruit or vegetable. The latter layer is spot welded to the layer
underneath. Accordingly the multilayer of material on the inside of
the carton is able to take up water in the vapour state when the
temperature drops and the RH rises. When the temperature rises the
multilayer releases water vapour back into the carton in response
to a lowering of the RH. The condensation control system therefore
acts as an internal water buffer. The critical characteristic of
the system is the capacity of the wick layer for water. For dried
food applications, desiccants such as silica gel, molecular sieves,
CaO and natural clays (e.g. montmorillonite) are often contained
within TyvekTM sachets. Examples where these compounds are used
include the sachets MINIPAX and STRIP-PAX and the moisture
absorbing label DesiMax (United Desiccants, USA) and the sachets
Desipak, Sorb-it , Tri-sorb and 2-in-1TM(Multisorb technologies,
USA).
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3.6.4 : Oxygen scavengers
Oxygen is such a broadly effective agent of deterioration in
foods that a substantial industry has been established to provide a
wide range of alternative means of oxygen removal from package
headspaces to reduce chemical deterioration. The choice of method
of oxygen removal depends upon both economic factors and upon the
properties of the particular food. In practice the application of a
short inert-gas flush coupled with use of a scavenger is likely to
be an attractive combination. The performance of oxygen scavenging
sachets depends strongly on the equilibrium relative humidity of
the food and the range of sachets available. The inclusion of
iron-based scavenging compositions in sachets has been improved by
development of adhesive scavenging labels for the inner wall of
packages.
Iron based oxygen scavenger
Sachet Based should be Permeable to O2& H2O; 1gm absorbs
~300 cc of oxygen; LD50 = 16mg/kg body wt.
Fig 3.11 Oxygen scavenger pouchScavenging mechanism:Fe Fe+2+
2e1\2 O2+ H2O + 2e- 2OHFe+2+ 2OH- Fe(OH)2Fe(OH)2+ 1\4 O2
Fe(OH)3Technologies for thin films typically used in MAP systems
need an additional feature to prevent premature reaction if they
are to provide maximum scavenging capacity. The
transition-metal-catalyzed (optionally light-activated) process
patented by W.R. Grace, Inc. approaches this by pre-planned
activation involving generation of full capacity by consumption of
antioxidants. This type of film, involving side-chain oxidation of
a polydiene, appears to be designed as a permeation barrier for
chilled, short shelf life processed meats. Amoco Chemicals have
reported some performance data for their Amosorb, water-activated,
masterbatch for blending into a variety of plastics. No
compositional detail is yet provided but the masterbatch and
plastics incorporating it are stable at relative humidities below
40%.The development of yellow colour or fluorescence in an oxygen
scavenging plastic film has been proposed as a means of monitoring
the initial scavenging capacity of such films or as a heat seal
leakage indicator in filled packages.The oxygen scavengers were
incorporated in LLDPE film fo increase the shelf life of bread and
bun(CFTRI). Ageless (Mitsubishi Gas Chemical Co., Japan) is the
most common O2scavenging system based on iron oxidation. The
sachets are designed to reduce O2levels to less than 0.01%. A rule
of thumb is that 1g of iron will react with 300 cc of O2. When the
initial O2Concentration at the moment of packaging and the
O2permeability of the packaging material is known, an absorber can
be chosen. However, a potential risk could be accidental ingestion
of a large amount of iron, in spite of the label `Do not Eat'.
Other iron-based O2absorbent sachets are the ATCO O2-absorber
(Standa Industrie, France), the Freshilizer Series (Toppan Printing
Co., Japan), Vitalon (Toagosei Chem. Industry Co., Japan),
Sanso-cut (Finetec Co., Japan) and Freshpax (Multisorb Technologies
Inc., USA).An alternative to sachets is the incorporation of the
O2scavenger into the packaging structure itself. Low molecular
weight ingredients may be dissolved or dispersed in a plastic or
the plastic may be made from a polymeric scavenger. An example is
Oxyguard (Toyo Seikan Kaisha, Japan), an iron-based absorber which
can be incorporated into a laminate. The main alternative to
dispersal of iron in plastics is organic reactions of plastics
themselves. Oxbar is a system developed by Carnaud-Metal Box (UK)
which involves cobalt-catalysed oxidation of a nylon polymer
blended especially in PET-bottles for plastic packaging of wine,
beer, sauces and other beverages. It should be noted that the speed
and capacity of O2scavenging films are considerably lower compared
with iron-based O2scavenger sachets. Other recent developments
include inserts in the form of flat packets, cards or sheets, as
well as O2scavenging adhesive labels, like Freshmax (Multisorb
technologies, USA) and the ATCO labels (Standa Industrie,
France).Ascorbic acid is another O2scavenging component which can
be used. The Pillsbury Co. holds a 1994 patent that also utilizes
ascorbic acid as reducing agent. A transition metal, copper, is
used to catalyse the oxidation reaction. The product, referred to
as Oxysorb can be included inside a pouch or may be incorporated
into the packaging. Another O2scavenging technique involves sealing
of a small coil of an ethyl cellulose films containing a dissolved
photosensitive dye and a singlet O2acceptor in the headspace of a
transparent package. Due to illumination of the film with light of
the appropriate wavelength, excited dye molecules sensitize
O2molecules, which have diffused into the polymer, to the singlet
state. These singlet O2molecules react with acceptor molecules and
are thereby consumed.
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3.6.5 : Antimicrobial packaging
The surfaces of plastics can be made not only sterile but also
capable of having an antimicrobial effect on the packaged food or
beverage. This type of effect has already been achieved in outer
layers of laminates by use of modified printing presses.
Horseradish extract on a cyclodextrin carrier has been used in a
drip sheet for fish or in a film wrap for lunches in Japan.
Approaches to antimicrobial packaging can be classified as either
of two types. The first consists of binding an agent to the surface
of packages and this would require a molecular structure large
enough to retain activity on the microbial cell wall even though
bound to the plastic. Such agents are likely to be limited to
enzymes or other antimicrobial proteins. The second approach
involves the release of agents into the food or beverage or
localized removal of a food ingredient essential for microbial
growth.Release of antimicrobial agents will be restricted by
regulatory approval as intended food additives. This is not
necessarily a serious restriction as the goal of the approach is
merely to maintain an appropriate concentration of the agent on the
surface of the food which may have been effectively inoculated with
microorganisms due to cutting or slicing. This concept has been
advanced in the case of an edible coating. An alternative approach
which has been developed in Japan by Mitsubishi is based on the
inclusion of zeolite particles in the surface of the food-contact
layer in laminates. The zeolite has some of its surface atoms
replaced by silver which appears to release silver ions as aqueous
solution from the food enters the exposed cavities of the porous
zeolite structure. The extent of food contact depends upon the
zeolite particles having a diameter greater than the thickness of
the layer in which they have been embedded. The water then appears
to leach traces of silver from the particles giving the highly
efficient antimicrobial activity of this ion. The effect is
unlikely to be as great in foods where there is a substantial
content of amino acids capable of reacting with silver ion. These
include acids such as cysteine. The use of edible coatings to apply
relatively constant concentrations of permitted antimicrobial
agents at the food surface has been developed. The relative rates
of diffusion within the coating and within the food itself are very
important. Such a process could be important where antimicrobial,
such as sorbate, are lost by degradation. Application of
antimicrobial via edible coatings appears likely to gain importance
with minimally processed foods distributed under MAP conditions.To
control undesirable microorganisms on foods, antimicrobial
substances can be incorporated in or coated onto food packaging
materials. The principle action of antimicrobial films is based on
the release of antimicrobial entities, some of which could pose a
safety risk to consumers if the release is not tightly controlled
by some mechanisms within the packaging material. The major
potential food applications for antimicrobial films include meat,
fish, poultry, bread, cheese, fruits and vegetables.Several other
compounds have been proposed and/or tested for antimicrobial
activity in food packaging including organic acids such as sorbate,
propionate and benzoate or their respective acid anhydrides,
bacteriocins e.g. nisin and pediocin, enzymes such as lysozyme,
metals and fungicides such as benomyl and imazalil. A film contains
a natural antimicrobial compound derived from grape- fruit seed. A
rarely mentioned possibility for manufacturing antimicrobial films
is to incorporate radiation-emitting materials into films. However,
little direct evidence for the efficiency of this technology has
been published in the scientific literature. Many of the
incorporated antimicrobials are not yet permitted for food use. The
choice of the antimicrobial is often limited by the incompatibility
of the component with the packaging material or by the heat
liability of the component during extrusion. One per cent potassium
sorbate in a LDPE film inhibited the growth of yeast on agar
plates. The LDPE resin and potassium sorbate powder can be mixed,
extruded and pelletized to produce a masterbatch. These pellets can
be added to LDPE resin. The masterbatch should be produced at low
temperature to prevent heat decomposition of the potassium sorbate.
Another study, however, found the relatively polar sorbate,
benzoate and propionate to be incompatible with the apolar LDPE.
Acid anhydrides were thought to be more compatible than free acids
and their salts because of their lower polarity. Two commercial
biocidal films are currently marketed. One is composed of a
chlorinated phenoxy compound and the other consists of chlorine
dioxide. A commercial antifungal coating containing chitosan is
also sold as a shelf-life extender for fresh fruit. Specific trade
names or effectiveness of these commercial products were not
mentioned. An interesting commercial development is the recent
marketing of food-contact approved Microban (Microban Products Co.,
USA) kitchen products such as chopping boards, dish cloths, which
contain triclosan, an antimicrobial aromatic chloro-organic
compound, which is also used in soaps, shampoos, etc. In EU
countries, however, the use of triclosan for food-contact
applications is not allowed and the SCF (Scientific Committee for
Food) has currently major objections against the use of triclosan
in food contact materials.Another compound that exhibits
antimicrobial effects is ethanol. Spraying ethanol onto foods prior
to packaging can be applied, but another option is to use sachets
generating ethanol vapour. Ethicap or Antimold from Freund
Industrial Co. (Japan) consists of a 55%/10% ethanol/water mixture
adsorbed onto silicon dioxide powder (35%), contained in a sachet
of a laminate of paper/ethyl vinyl acetate copolymer. Ethicap acts
by absorbing moisture from the food and releasing ethanol vapour.
Using Ethicap ,yeast growth was suppressed completely in all
packages during 21 days at 200C. Negamold (Freund Industrial Co.),
scavenges O2as well as generating ethanol vapour. Other ethanol
generators are Oitech TM(Nippon Kayaku, Japan), Ageless type SE
(Mitsubishi Gas Chemical Co.) and ET Pack (Ueno Seiyaku, Japan).
Ethanol vapour generators are widespread in Japan and are mainly
used for high moisture bakery goods, fish products and cheese. A
major disadvantage of ethanol vapour is its absorption by the food
product. In some cases the ethanol concentration in the product
might cause regulatory problems. If the product is heated prior to
consumption the accumulated ethanol may evaporate. Another drawback
is the cost of the sachets, which limits their use to products with
higher profit margins.
TOP
3.6.6 : Breathing films
Permeability regulations via. Thermally sensitive packaging
materials.A significant development is that of
side-chain-crystallisable (SCC) polymers with the ability to
effectively and reversibly melt as the temperature increases and
thus foster increased gas transmission through them. SCC polymers
are acrylics with side-chains independently of the main chain. By
varying the side-chain length, the melting point can be altered. By
making the appropriate copolymers, it is possible to produce any
melting point from 0 to 68C., well within the extreme distribution
temperature range of minimally processed foods. When elevated to
the switch temperature, SCC polymers become molten fluids which are
inherently high in gas permeability. The permeation properties may
be modified by inclusion of other polymers to change the carbon
dioxide to oxygen permeability ratios, for example. The resulting
materials can permit the packaging technologist to achieve the
lowest oxygen concentration without going anaerobic within the
package. Thus, the optimum gas concentration may be employed from
the outset of distribution with minimum concern for elevated
temperatures. In addition to the reversible temperature
sensitivities, the materials are generally capable of 100 times
greater oxygen permeability than mainstream polyethylene films
without compromising the carbon dioxide to oxygen permeability
ratio. This is accomplished by coating a porous substrate with a
proprietary SCC polymer and applying the membrane as a package
label over an aperture on an otherwise reasonably well sealed
package. Membranes with high carbon dioxide to oxygen ratio
selectivity are best for products with carbon dioxide sensitive
contents to allow the carbon dioxide to escape at rate faster than
oxygen can enter. Conversely, membranes with low ratios are more
applicable to products in which high carbon dioxide values can
inhibit microorganisms. Thus, the materials can be tailored to the
exact requirements of the package contents. These SCC materials are
manufactured by Landec Corp. Menlo Park, California.Check Your
Progress Exercise 3Note: a) Use the space below for your answer b)
Compare your answer with those given at end of the unit.1. What an
oxygen absorber is made
of?................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................2.
Why use oxygen
absorber?................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................3.
What are the benefits of using
O2absorbers?................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................4.
What is Intelligent
Packaging?................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
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3.7 : Biodegradable Packaging
Biodegradable plastics are plastics that will decompose in
natural aerobic (composting) and anaerobic (landfill) environments.
Biodegradation of plastics can be achieved by enabling
microorganisms in the environment to metabolize the molecular
structure of plastic films to produce an inert humus-like material
that is less harmful to the environment. They may be composed of
either bio plastics, which are plastics whose components are
derived from renewable raw materials, or petroleum-based plastics
which utilize an additive. The use of bio-active compounds
compounded with swelling agents ensures that, when combined with
heat and moisture, they expand the plastic's molecular structure
and allow the bio-active compounds to metabolize and neutralize the
plastic.
ASTM International defines appropriate testing methods to test
for biodegradable plastic, both anaerobically and aerobically as
well as in marine environments. The specific subcommittee
responsibility for overseeing these standards falls on the
Committee D20.96 on Environmentally Degradable Plastics and
Biobased Products . The current ASTM standards are defined as
standard specifications and standard test methods. Standard
specifications create a pass or fail scenario whereas standard test
methods identify the specific testing parameters for facilitating
specific time frames and toxicity of biodegradable tests on
plastics.
Examples of biodegradable plastics
Most aliphatic polyesters are biodegradable due to their
potentially hydrolysable ester bonds: Naturally Produced:
Polyhydroxyalkanoates (PHAs) like the poly-3-hydroxybutyrate (PHB),
polyhydroxyvalerate (PHV) and polyhydroxyhexanoate (PHH); Renewable
Resource: Polylactic acid (PLA); Synthetic: Polybutylene succinate
(PBS), polycaprolactone (PCL), Polyanhydrides, Polyvinyl alcohol,
Most of the starch derivatives and Cellulose esters like cellulose
acetate and nitrocellulose and their derivatives (celluloid).
Fig 3.12 Utensils made from biodegradable plastic.Advantages and
disadvantagesUnder proper conditions biodegradable plastics can
degrade to the point where microorganisms can metabolise them.
Degradation of oil-based biodegradable plastics may release
previously stored carbon as carbon dioxide. Starch-based
bioplastics produced from sustainable farming methods can be almost
carbon neutral but could have a damaging effect on soil, water
usage and quality, and result in higher food prices. There are
concerns over "Oxo Biodegradable (OBD)" plastic bags. These are
plastic bags which contain tiny amounts of metals such as cobalt,
iron or manganese. They degrade in the presence of sunlight and
oxygen, but there are concerns about the metals leftover and the
time it takes for the plastics to degrade in certain circumstances.
Microbial consumption of polymers are available through addition of
hydrophilic type additives onto the surface of the polymer chains.
These types of additives are readily available and are used
worldwide. The advantages of using these types of materials are
heat stability, methane capturing and product performance.
Check Your Progress Exercise 4
Note: a) Use the space below for your answer b) Compare your
answer with those given at end of the unit.
1. What are the main types of biodegradable plastics and how do
they
differ?......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
2. What are the end products of biodegradation and do they have
any harmful effect on the
environment?.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
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3.8 : Let us sum up
Convenience is the latest word in the food packaging industry
with consumers on the constant look out for ready to eat meals. In
recent times, food packaging innovations have made it possible to
preserve the food fresh with good shelf life without changing the
quality of the packaged food. Rising income, changing lifestyles
and technology, as well as the widespread popularity of
microwaveable foods is driving the use of portion and plastic
packaging. In the future, partnerships between the food processor
and the packaging industry are likely to be a crucial step toward
more rigid, stable, and resalable packages. Development in commonly
used packaging materials such as glass, plastics, light metals, and
paperboard throws light on certain food packaging techniques namely
aseptic packaging, retort packaging, active packaging, controlled
atmosphere storage, and modified atmosphere packagingVacuum
packaging is removes all headspace air from the package before
final sealing of the container/ pouch. This helps in extending the
shelflife. It requires gas barrier packaging material. Gas
packaging is another way of extending of shelf life of different
foods. For the fresh meat oxygen is required to maintain the red
colour. CO2is used to inhibit the microbial growth and nitrogen is
used as inert gas to displace O2is order to delay oxidative
deterioration of foods.Aseptic packaging is a presterilization of
food and packaging in sterile package and sealing hermatically to
prevent the reinfection of the foods. Basically the processes used
in dairy products, fruits and vegetables and juices.Retort
packaging is cooking process of foods inside package itself at
higher temperature and pressure. packaging requires strength
toughness, puncture and burst resistance. Materials used are glass
metal- cans and thermally stable multilayer pouches.Active
packaging is another emerging area where the extra properties are
provided from the package by incorporation of active ingredients
package material. Ethylene scavengers are necessary to delay the
ripening of fruits and vegetables. KMnO4 is used to oxdise
ethylene, Ca(OH)2is used as active compound to react with CO2formed
due to respiration of fresh produce, Humectent are used to reduce
surface water by reducing the pH in pack. Iron based O2scavenger
are used to reduce the O2level less than 0.01% are highly
O2sensitive foods.The food package industry is realizing that with
the increasing health consciousness among consumers, understanding
the interactions between the food, package, and the environment are
essential for more efficient food packaging solutions.
Multidimensional functionality is the key goal in the packaging
industry today, Packaging is now more inclined toward aspects such
as increasing shelf life, ensuring food safety through control of
the environment within the package, and minimizing damage resulting
from microbial attack.
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3.9 : key words
CO2 Carbon dioxideO2 oxygenN2 NitrogenPET Polyethylene
terephthalatePE PolyethyleneAL AluminiumLLDPE Linear low-density
polyethylenePA PolyamideCPP Coextruded polypropyleneC2H4
EthyleneCaO Calcium oxideEMA Ethylene Methyl Acrylate CopolymerMAP
Modified atomospheric pressurePLA Polylactic acidPHA
PolyhydroxyalkanoatesPHB PolyhydroxybutyrateEVOH Ethylene Vinyl
AlcoholHTST High Temperature Short Time
Head SpaceThe gaseous constituents of a closed space above
liquids or solid in the container
Shelf lifeShelf life is the recommendation of time that products
can be stored, during which the defined quality of a specified
proportion of the goods remains acceptable under expected (or
specified) conditions of distribution, storage and display.
ScavengersA chemical substance added to in order to remove or
inactivate impurities or unwanted reaction products.
EmittersThe substance (chemical or combination of chemicals)
used to give or send out required chemicals or gases
Aseptic processingThe process by which a sterile (aseptic)
product (food) is packaged in a sterile container in sterile
atmosphere in a way which maintains sterility.
Co-extrusionThe process of extruding two or more materials
through a single die with two or more orifices arranged so that the
extrudates merge and weld together into a laminar structure.
Retortan airtight vessel in which substances are heated at
required temperature.
InhibitorA substance that decreases the rate of or prevents a
chemical reaction.
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3.10 : Answers to check your progress exercises
Check Your Progress Exercise 1Your answer should include the
following points:1. The process of removing air around a food
product and then sealing the product in an impermeable package.2.
Removing the air that surrounds food inhibits growth of bacteria,
mold, and yeast because these and other spoilage microorganisms
need oxygen to grow. Once most air is removed and the pouch is
sealed, oxygen levels continue to drop while carbon dioxide levels
increase. The low oxygen, high carbon dioxide environment
significantly reduces the growth of normal spoilage organisms,
allowing longer shelf life.3. Some of the advantages include:
Vacuum packaging reduces product shrinkage. There is no moisture
loss or evaporation in a sealed vacuum bag. Therefore, the weight
you package will be the weight you sell. Vacuum packaging reduces
trim losses by eliminating oxidation and freezer burn. Vacuum
packaging can enhance product quality. Vacuum packaged meat held at
32 to 35 does not hinder aging or tenderizing. Vacuum packaging
allows more efficient use of time. Food can be prepared in advance
without loss of freshness, so slack times are more productive and
busy times are more manageable.4. The process of controlled purging
of inert gas inside a flexi pouch and sealing the mouth of the
pouch with gas inside in sequence, is called inert gas packing. You
can vacuummize and purge the pouch inside the INDVAC chamber type
machine or you can vacuummize and purge or only purge a flexi pouch
in INDVAC nozzle type machine.5. Yes, the conventional monolayer
pouches are not suitable as they do not have barrier property. You
need to use multi layer pouches with either polyester, nylon or
aluminium foil barrier layers.Check Your Progress Exercise 2Your
answer should include the following points:1. The special aseptic
process yields a shelf-stable product, which can be kept in a
cupboard for extended periods of time without preservatives or
refrigeration. In describing their preference, consumers often
point to the safety, nutrition, and ease of handling of the aseptic
package. Others prefer the aseptic carton because it is
shatter-proof and tamper-evident.2. Aseptically processed liquid
foods and beverages are sterilized outside the package using an
ultra-high temperature process that rapidly heats, then cools, the
product before filling. This flash-heating-and-cooling aseptic
process substantially reduces the energy use and nutrient loss
associated with conventional sterilization. As a result,
aseptically packaged products retain more nutritional value, and
exhibit more natural texture, colour, and taste.Check Your Progress
Exercise 3Your answer should include the following points:1. An
oxygen absorber is made of a chemical compound, the active
ingredient of which is an Iron Powder (Fe).2. When food has an
oxygen environment, it can become moldy. It can oxidize, the colour
can change, microorganisms can thrive, and the taste can change.
With oxygen present, toxins can grow as by products of bacteria.3.
It extends food shelf life. It prevents the growth of aerobic
pathogens and spoilage organisms, including molds. It eliminates
the needs for additives such as BHA, BHT, sulphur dioxide, sorbets,
benzoates, etc. Use with gas flushing packaging to absorb virtually
all oxygen and absorb any oxygen that may permeate the package.4.
Intelligent packaging refers to packaging systems that influence of
packaging so that the condition of food is monitored. It helps to
extend the shelf life, to monitor freshness and to improve safety
of the packaged product.Check Your Progress Exercise 4Your answer
should include the following points:1. There are 2 main types of
biodegradable plastics: oxo-biodegradable and hydro- biodegradable.
Both will first undergo chemical degradation by oxidation and
hydrolysis for oxo- and hydro-biodegradable plastics respectively.
This results in their physical disintegration and a drastic
reduction in their molecular weights. These smaller, lower
molecular weight fragments are then amenable to biodegradation.2.
The end products of biodegradation are carbon dioxide, water and
biomass. Extensive studies and tests have been conducted by EPI
with internationally recognized laboratories and institutions to
confirm that they do not leave harmful or toxic residues to the
environment.
TOP
3.11 : Some useful books
1. Aaron L. Brody, Eugne R. Strupinsky, Lauri R. Kline.
(2001)Active packaging for food applicationsTechnomic Pub. Co.,
Technology & Engineering.2. Gordon L. Robertson (2006)Food
packaging: principles and practice Taylor & Francis/CRC Press,
2006 - Technology & Engineering.3. Jung H. Han
(2005)Innovations in food packagingAcademic Press, - Technology
& Engineering.4. David K. Platt,(2006) Rapra Technology
LimitedBiodegradable polymers: market report iSmithers Rapra
Publishing.5. Matche Rajeshwar S (2001)Packaging Machinery, in
Handbook of Frozen Food Processing and PackagingEdited by Da-Wen
Sun, Taylor & Francis/CRC Press.
MFT-004>>Block-1>>Unit-4>>
Unit-4:Packaging Machinery