Introduction to food packaging sir ppt)
-
Upload
priyankashukla27dec -
Category
Food
-
view
1.217 -
download
111
Transcript of Introduction to food packaging sir ppt)
•Packaging sector represents 2% of the gross national production developed countries.
•Packaging is defined as a socio-scientific discipline that operates in society to ensure thedelivery of goods to the ultimate consumer in the best condition intended for their use(Lockhart 1997)
•The word ‘package’ means the physical entity that contains the product.‘Packing’ can bedefined as the enclosing of an individual item(or items) in a package or container.
•Levels of packaging:-
A.) Primary package(direct contact with the food)
B.)Secondary package(contains number of primary packages, e.g. corrugated case or boxetc.)
•Functions of packaging:-
a.)Containment
b.)Protection
c.)Convenience
d.)Communication
•Packaging environments:- Packaging performs its functions in three environments
a.)Physical environment (includes shocks, drops, falls etc.)
b.)Ambient environment (surrounds the package)
c.) Human environment ( package interacts with the people)
2. Structure and Properties of Plastic Polymers
The word plastic has been derived from Greek Plastikos meaning easily shaped or deformed.
Properties of plastics are determined by :-
1.)Chemical and physical nature of the polymers
2.) Molecular structure and weight of polymers
3.)Degree of crystallinity
Different additives are added to obtain better products such as, plasticizers(e.g. DOP,DOA etc.),antiaging additives, surface property modifiers etc.
Classification of polymers on different basis:-
(A)Chemical composition (B) Molecular structure
Homopolymers Heteropolymers Linear polymers Branched/Cross-linked
(C) Polymerization process (D) Heating properties
Addition Condensation Thermoplastics Thermosetting plastics
Example of plastic polymers:- Polyolefins(LDPE,HDPE,LLDPE), Polypropylene, Polyethylene, Polystyrene, Polyvinyl Chloride, Polyesters, Polycarbonates, Polyamides,
3. Edible, Bio-based and Biodegradable Food Packaging Materials
Edible packaging consists of edible films, sheets, coatings and pouches which canbe consumed with the packaged product.
Functions:
A.)Selective barrier to retard the migration of moisture
B.)Gas transport
C.)Oil and fat migration and Solute transport
D.)Improve the mechanical handling properties
E.) Retain volatile flavour compounds Edible film
F.)Carry additives such as anti-oxidants and antimicrobials
Example: Polysaccharides, Starch, Cellulose, Hemicellulose, Chitosan, Gums, Lipids,Proteins etc.
Biobased packaging material:-These are made from renewable raw materials and canbe classified according to their origin and method of production such as, polymersdirectly extracted from biomass such as starch, cellulose, polymers produced byclassical chemical synthesis, or naturally or genetically modified organisms etc.
Biodegradable plastics:-It is a degradable plastic in which the degradation processresults in lower MW fragments produced by the action of naturally occurring micro-organisms such as bacteria, fungi and algae. Example:-Starch, polylactic acid,polyhydroxyalkanoates, polycaprolactone etc.
4. Properties of Thermoplastic Polymers
Optical properties
These are related to both the degree of crystallinity and actual polymer structure.
These include- clarity, haze, colour, transmittance, reflectance, gloss and refractive
index.
Tensile Properties
These include- tensile and yield strength, elongation and Young’s modulus.
Bursting strength, Impact strength, Tear strength, Stiffness, Crease or flex resistance,
Coefficients of friction, Blocking and Orientation and shrinkage are also included in
tensile properties.
Barrier properties
The barrier properties of plastics indicate their resistance to sorption and diffusion
of substances such as gases and flavour and aroma compounds.
The term sorption is generally used to describe the initial penetration and dispersal
of important molecules into the polymer matrix and includes both adsorption and
absorption as well as cluster formation.
5. Processing and Converting of Thermoplastic Polymers
(A) Extrusion:-
It is the most important plastics processing methods in use today.
It can be defined as continuously forcing a molten material through a shaping
device.
It includes monolayer extrusion and coextrusion
The screw is the heart of extruder
(B) Calendaring:-
It is a complementary process to film and sheet extrusion and involves the
formation of continuous sheets of evolved thickness by squeezing a heated plastic
material between two or more horizontal rollers.
Contd…
(C) Coating and Laminating:-
Coating and laminating are two of the most widely used processes for transformingflexible films and sheets into products having properties useful in food packaging.
Coating is the process of applying one or more layers of a fluid or melt to thesurface of a material, while laminating is the bonding of two or more webs.
(D) Blending:-
Polymer blending is a low-cost alternative route to multilayer extrusion.
(E) Vapor Deposition:-
It is a general term used to describe any of a variety of methods to deposit thin filmsby the condensation of a vaporized form of the material onto various surfaces.
(F) Orientation:-
It is a means of improving their strength and durability in order to broaden theirscope of application and make them serviceable in thinner gauges.
It involves the stretching the material in such a manner so as to line up themolecular chains in a predetermined direction.
(G) Cross-Linking:-
It interferes with molecular packing, reduces the level of crystallization and,consequently, results in a polymer with a low hardness and yield strength.
(H) Thermoforming:-
A sheet of thermoplastic material is heated to its softening temperature, usually bymeans of an infrared radiant panel heater.
6.Paper and paper-based packaging materials
Pulp:
It is the fibrous raw material for the production of paper, paperboard, corrugated
board and similar manufactured products.
About 97% of the world’s paper and board is made from wood pulp and 85% of the
wood pulp used is from spruces, firs and pines.
Wood pulp contains mainly cellulose, hemicellulose and lignin.
Paper:-
Paper derives its name from the reedy plant papyrus.
Most properties of paper depend on direction
Paper is divided into two broad categories: fine papers( typically used for writing
paper,bond,l edger, book) and coarse papers (used for packaging).
Different types of paper include- kraft paper, bleached paper, greaseproof paper,
glassine paper, waxed paper and vegetable parchment paper.
Paperboard:
Paper is generally termed board when its grammage exceeds 250gsm.
Folding cartons are made from sheets of paperboard which have been cut and
scored for bending into desired shapes.
7. Metal Packaging Materials
Four metals commonly used for the packaging of foods are- steel, aluminium. tin
and chromium
(A)Tinplate: It refers to low-carbon, mild steel sheet varying in thickness.
Manufacture of pig iron
Steelmaking
Tinplating
(B)Aluminium: It is the Earth’s most abundant metallic constituent. It is a lighter,
weaker but more ductile material that cannot be soldered. It is used for the
manufacture of containers, foils. Retort pouches, tubes and bottles.
(C) ECCS: Electrolytic chromium/chromium-oxide-coated low-carbon steel sheet
It is prepared by electrotinning. It consists of a duplex coating of metallic
chromium and chromium sesquioxide.
8. Glass Packaging Materials
Glass is “an amorphous , inorganic product of fusion that has been cooled to a rigid
condition without crystallising”.
The two main types of glass container used in food packaging include-
bottles(which have narrow necks) and jars (which have wide openings).
Principal ingredient- silica
Manufacture process:
Mixing and Melting
Forming process
Blow & Blow process
Annealing
Surface treatment
9.Printing and Labelling process of Packaging Materials
Basic principle of printing-Ink is deposited on an engraved plate and the inked
image is transferred to the substrate through contact.
Different methods of package printing :-
a.) Conventional methods of printing (relief, letterpress, flexography and flexo process)
b.) Gravure/intaglio (more commonly known as rotogravure printing)
c.) Lithography (offset lithography/ planographic printing)
d.) Screen printing ( stenciling process)
e.) Digital printing methods (printing from a digital source)
f.) Electrophotography ( oldest nonimpact printing technology).
Labeling is a means of performing the communication function of packaging,
informing the consumer about nutritional component, net weight, product use and so
on. It includes various labels such as- glued-on labels, self-adhesive labels, in-mold
labels, sleeve labels holographic labels etc.
Coding includes a “closed” code on the packaged product such as bar code which is
defined as a series of parallel bars and spaces arranged according to the encodation
rules of a particular specification in order to represent the data.
10. Food Packaging Closures and Sealing Systems
Closures mainly consist of cap, lid or cork to seal the jar or bottles.
Functions:
1.)Provide hermetic seal
2.) Provide easy opening
3.) Provide evidence of inviolability.
Closures are made from either metal or plastic
For closures either heat or cold sealing is done.
Heat sealing involves welding thermoplastic polymer surfaces together in order to produceseals or joints of sufficient strength to withstand stresses.
Cold sealing is done for the packing of heat-sensitive foods such as chocolate, chocolate-coated biscuits, ice-creams etc.
Peelable seal technology provides retention of package integrity and also allows consumers toaccess the contents without tearing or destroying the package.
Plastic closures Easy open ends(EOE) Metal closure
11. Deteriorative Reactions in Foods
Deteriorative reactions in food
Enzymic reactions Chemical reactions Physical changes Biological changes
Sensory quality Caking
Nutritional quality
Microbiological Macrobiological
Factors controlling the rates of deteriorative reactions in foods
Intrinsic factors Extrinsic factors
Water activity Temperature
Oxidation-reduction potential Gas atmosphere
Light
12. Shelf Life of Foods
The finite length of time from production to unacceptability is referred to as shelf life.
Shelf-life determination is required:
a.) To determine the shelf-life
b.)To study the effect of specific factors
c.) To determine the shelf life of prototype.
Shelf-life can be determined from two sides:- product side or consumer side.
Determination from product side includes sensory evaluation or combination with
instrumental or chemical analysis.
Shelf-life is controlled by three factors:
a.) Product characteristics (perishability, bulk density, concentration effects)
b.)Package properties (water vapour transfer, gas and odour transfer, light transmission,
package dimensions, package/product interactions)
c.)Distribution and storage environment (climatic and physical)
13. Aseptic packaging of foods
Aseptic packaging is the filling of sterile containers with a commercially sterile
product under aseptic conditions and then sealing the containers so that reinfection
is prevented.
The first aseptic packaging of food was carried out in Denmark by Nielsen.
Criteria for aseptic packaging system:-
1.) Able to be connected to the processing system
2.) Able to be effectively sterilized before use
3.) Able to carry out the filling, sealing and critical transfer operations in a sterile
environment.
4.) Able to be cleaned properly after use.
Sterilization processes used are- HTST and UHT.
Aseptic packaging systems may include carton systems, can systems, bottle systems,
cup systems, sachet and pouch systems.
14. Packaging of Microwavable Foods
Microwaves use electromagnetic waves at frequencies between 300MHz and 300
GHz.
Microwaves are generated by magnetron which consists of a vacuum tube with a
central electron-emitting electrode.
In microwave oven, foods are placed in an electromagnetic field at ambient
temperature and heat is generated by the food’s own ingredients.
Packaging materials can react in three ways to microwaves:-
a.) they can reflect the radiation
b.) absorb the radiation RAT characteristics
c.) transmit the radiation
Various packaging materials used to package microwaved foods:-
1.) Transparent materials
2.) Absorbent materials
3.)Shielding and field modification
15.Active and Intelligent Packaging
Smart packaging are defined as “doing more than just offer protection”.
Active packaging is defined as packaging in which subsidiary constituents have
been deliberately included in or on either the packaging material or the packaging
headspace to enhance the performance of the package system.
Intelligent packaging is defined as packaging that contains an external or internal
indicator to provide information about the history of the package and quality of the
food.
Smart Packaging Active Packaging Intelligent Packaging
Active packaging materials include: Intelligent packaging materials include:
A.)Oxygen absorbing materials a.)Quality/freshness indicators
B.) Ethylene adsorbers b.) Time-Temperature indicators
C.) Antioxidant Packaging c.) Gas concentration indicators
D.) Antimicrobial Packaging d.)Biosensors