FOOD PACKAGING TECHNOLOGY

WHAT IS FOOD PACKAGING?

Food packaging is packaging for food. A package provides protection, tampering resistance, and special physical, chemical, or biological needs. It may bear a nutrition facts label and other information about food being offered for sale.

WHAT DOES PACKAGING DO?packaging preserves food and prolongs its shelf life by protecting it from bacterial damage, moisture and insect attack. Some packaging preserves food for a very long time, such as tins.Today, due to the way we shop,packaging also prevents tampering, provides information and attracts customers.

General requirements of food packaging: Nontoxic Prevent contamination from microorganisms &

environmental toxicants Barrier to moisture, oxygen, UV light & odors Provide resistance to physical damage Be tamper-resistant or tamper-evident Easy to open Have dispensing & resealing features Be disposed of easily Meet size, shape & weight requirements Have appearance, printability features Have low cost Be compatible with food Be transparent

OBJECTIVES The objectives of packaging include:• prevent physical damage, e.g. from knocking, shaking or crushing;• prevent contamination from micro-organisms, pollution or vermin;• protect against dehydration or dampness;• protect the product’s nutritional and sensory characteristics;

contain the product and keep it intact.

liquid products do not leak and that dry materials, such as flour, do not spill out.

Well protection form damage

keep the product in peak condition;

help to increase a product’s shelf life.

FUCNTIONS OF PACKAGING To protect a product from damage or

contamination. To keep the product together, to contain

it (i.e. so that it does not spill). To identify the product. Protection during Transport and Ease of

Transport. Stacking and Storage.

TYPES OF PACKAGING Aluminium container Aluminium foil Paper1. kraft paper2. coated paper3. brown paper for packing and wrapping4. greaseproof Plastics1. Polypropylene2. Polyvinyl chloride3. Polystyrene4. Polyester Cellulose film Glass laminates

GLASS

As related to food packaging is chemically inert. The principle limitation is susceptibility to breakage

which may be from internal pressure , impart thermal shock.

Preparation: soda ash ,lime stone and other material moulded by heating to about 1500 Celsius and send to oven to impart toughness.

The average life of a glass water in a soft drink industries is 4-6 years

ADVANTAGES:1. free of corrosion2. Glasses impermeable to both gas and liquid 3. odourless4. permitting full vision of package product and give

the feeling of cleanliness .

FUNCTIONAL REQUIREMENTS OF GLASS CONTAINERS

Mechanical impact strength Resistance to thermal shocks. Thermal endurance Resistance to internal pressure. Resistance to collapse Dimensional conformance of the finish Dimensional conformance of the body. Capacity Chemical durability Visual appeal.

TESTING OF GLASS CONTAINERS

VISUAL DEFECTS:1. It is examined against a glare-free illumination

from a suitable light source. CRITICAL DEFECTS:1. cracked or broken glass2. choked bore3. internal fins4. flanged fins5. over press6. Split finish7. Channelled and wrapped sealing surface8. Shifted finish9. Rocker bottom

MAJOR DEFECTS:1. stones2. seeds3. cords4. blisters5. rough sealing surface6. crizzle7. oil marks8. bad distribution9. Deformation HYDROSTATIC PRESSURE TEST:1. Bottles are filled with water and pressure is

applied by a pump.2. Pressure is raised to a specified limit at

which the container should not break

CHEMICAL DURABILITY TEST OF GLASSES

Low alkali glass like “neutral "or “boro silicate "is used.

Glasses are grouped into various types ( 1 to 5) according to their chemical durability i;e, extractible alkalinity.

Alkalinity is measure by treating it with a standard acid solution.

The user should be more concerned with the inside surface of the container

MAKING OF GLASS BOTTLES

Hot End Process:1. It employs high amounts of heat to

produce and shape a glass container. A furnace is first used to mould molten glass(glass feed stock).

2. calcium oxide,lime,silica,Soda-lime glass and small amounts of aluminium oxide, ferric oxide, barium oxide, sulphur trioxide, and magnesia for about 5 percent of soda-lime glass.

3. Before melting, cullet (recycled glass) is added to the stock, accounting for anywhere between 15 and 50 percent of the final glass composition.

After stock has been fed into furnace temp. is increased to 1675°F.

Next, one of two method forming methods is applied press-and-blow or blow-and-blow

ANNEALING:1. Once formation is complete, some bottles may

suffer from stress as a result of unequal cooling rates.

2. An annealing oven can be used to reheat and cool glass containers to rectify stress and make the bottle stronger.

COLD END PROCESSES:1. In this stage, the bottles or glass containers

are inspected and packaged. 2. Inspection is often done by a combination of

automated and mechanical inspection, to ensure the integrity of the final product. Common faults include checks, stones etc.which are important to catch because they can compromise the component.

CLOSURES

Closures are devices and techniques used to close or seal a bottle, jug, jar, tube, can, etc. Closures can be a cap, cover, lid, plug, etc.

Metals and plastics are basically used for their manufacturing.

Fabricated from tinplate, steel plate or aluminium.

Many containers and packages require a means of closing. It can be a separate

device or seal or sometimes an integral latch or lock.

PURPOSE OF CLOSURE:1. Keep the container closed and the

contents contained for the specified shelf life until time of opening

2. Provide a barrier to dirt, oxygen, moisture, etc. Control of permeation is critical to many types of products: foods, chemicals, etc.

3. Keep the product secure from undesired premature opening

4. Provide a means of reclosing or reusing the container

5. Assist in dispensing and use of product6. Allow reasonable ease to open the

container by the intended user.

TYPES OF CLOSURES

METAL CLOSURES: Fabricated from tinplate, mild steel plate or aluminium, they take different forms depending upon their needs of usage. They have EOE (easy opening ends)

CROWN CAPS:Used mostly for beverage bottles andother processed products. These are Shallow metal caps that are crimped into locking position around the head of the bottle.

LUG CAPS:They seal the vacuum inside the headspace of the glass bottle,they require puncturing to open it.Also known as twist-on twist-off caps. Used for jam bottles and other similar products.

PLASTIC CLOSURES:They are produced from polypropylene and are injection moulded .They allow venting outexcess gas pressure to prevent bursting.

Corkers1. Corks are mainly used to close wine bottles by

pressing them into the neck under considerable pressure while at the same time squeezing them, to reduce the diameter so that they will enter the bottle neck.

2. The corks are wetted before use so that they will slide more easily into the bottle neck.

3. they are soaked in a solution of sodium met bisulphite to avoid contamination to avoid contamination.

Plastic hinge-open snap-shut closures

1. They are becoming increasingly common for liquid products that are opened and closed several times in use.

2. Simple hand-operated presses are available to fit this type of closure.

3. Common applications include cooking oils, sauces and fruit toppings.

DISPENSING DEVICES:1. Dispensing device range from flip top

caps to cans.2. Used to dispense measured dosages.3. In aerosol sprays, specially designed

valve is used for uniform spraying having a definite particle size.

4. They are designed to ensurecomplete emptying of the container and avoiding wastage particularly for high value products

The design of the dispensing device depends on the following: Viscosity or flow properties of the

product Value of the product Accuracy of the output required Nature of the product

BAG-IN BOX SYSTEM:1. In packaging, a bag-in-box or BiB is a

type of container for the storage and transportation of liquids.

2. usually made of several layers of metallised film or other plastics, seated inside a corrugated fibreboard box.

3. Used to dispense bulk supplied condiments such as ketchup or mustard in the foodservice industry specifically in fast food outlets.

ADVANTAGES it is inexpensive. The bag allows a contents of 1.5–

1000 litres, so that less packaging or labelling is required.

The material it is made from is lighter than the other plastic alternatives providing it with a better carbon footprint.

CANS Cans were traditionally made from tin plate

sheet, but now more commonly aluminium is used (for drinks).

The inside of the can is often sheet coated with lacquers to prevent the cans rusting and reacting with the contents, especially acidic foods.

The effectiveness of tin coating depends upon its thickness method of applying (electrolytic plating ,composition of the under living steel) types of food and other factor(temp., pressure, humidity etc.)

TYPES OF CANNS

FULL TOP CANN- mostly made of Al+2 which has a key opening device it contains a lacquer waiting for packaging the acidic foods

PASSIVATION-external surface of a cann are treated when canns are held in or exported to warm humid areas ,dis treatments prevents resulting of canns .

SLIP OVER LID- This is the sanitary opening cover is reversible ,air tight and temper to sealing can be done .

COFEE CANNS- guiding a plastic lid convenient to open .

COLAPSE CANNS- bulkiness and transportation can be achieved at low cost by delivering fatten cann bodies. They are reformed and bottoms are attached prior to filling.

AEROSOL CANNS-(pressurised cans) pressurised food packages or aerosol packages are two types-

A- Aerosal type-(foam) B-Wax spray – non aerated container ,(liquid)

dispenses material as a foam like whipped cream and wet spray non aerated container which dispenses material as a liquid for packaging in aerosol cans .

FOIL LAMINATED FIBRE CANNS -lighter in weight ,and lower in price example-fruit juice or juice concentrates.

UNIT PACKED CANNS –has both top and bottoms made of Mattel's which are seamed (sealed) of any type of martials ex-card board and are not made for reuse metal provide easy stacking .

TESTING METHODS OF TIN CONTAINERS

The testing methods include:1. Visual inspections for printing and

manufacturing defects2. Dimensions inspection3. Ready container height, capacity or

over seam diameter.4. Air pressure test for leakage5. Handle pull test6. Crush resistance test7. Product compatibility.

PLASTICSFood packaging uses a wide range of both rigid and flexible plastic materials including: polythene – low density is used as a film wrapping,

resistant to water. High density is used for ‘boil-in-the-bag’ products;

polyamide (nylon) – provides a very good barrier to oxygen, so used for vacuum packaging, especially for foods containing fat (which can be susceptible to oxidation).

Type 1 – PET is the most commonly used one (water containers); APET (fizzy drinks); CPET is heat resistant (oven ready-meal trays)

Type 4 – LDPE (plastic bags and bin liners) Type 5 – PP (margarine tubs and

microwaveable meal trays) Type 6 – PS is polystyrene (yoghurt pots,

plastic cutlery, egg cartons, vending cups and burger cartons)

Type 7 – other plastics that do not fall into any of the above categories (melamine and non-breakable plates and cups).

Type 2 – HDPE (milk and detergent bottles) Type 3 – PVC is banned in some countries

(food trays, cling film, bottles of squash, water and shampoo)

MAKING OF PLASTIC BOTTLES

Injection moulding Here grains of plastic polymer are heated by a screw in a moulding machine and then injected under high pressure into a cool mould. The method is mainly used for wide necked containers and lids.

Injection blow moulding- Polymer is injection moulded around a blowing stick and, while molten is transferred to the blowing mould. It is then blown into shape by compressed air.

Extrusion blow moulding- In this method a continuously extruded tube of softened polymer is trapped between the two halves of a mould. It is then inflated by compressed air into the mould.

Stretch blow moulding- A shape is prepared by either injection or extrusion moulding. It is then re-heated, which causes the molecules of plastic to 'line up'. This gives a glass clear container of greater strength which has good barrier properties to gases and moisture over a wide temperature range.

Blow moulding : is similar to glass bottle making and is used as a one or two stage process to make bottles, jars and pots

LAMINATES

Excellent barriers against microbes and dirt.

Eg. Of laminates include: polymer coated cellofin , metallic foil , polythene combined with aluminium foil.

CELLULOSE FILMS

Cellulose films are used for different types of food packaging, because they have a range of characteristics such as different degrees of moisture proofing.

Some cellulose films are heat sealable.

They can be used, for example, as window patches in cartons.

PAPER Often used for printing containers. Made from natural and occasionally synthetic

fibrous material being the precipitate of its suspension in water.

coated with waxes,raisins,plastics, laminates of aluminium to improve vapour and gas permeability.

Types of packaging paper1. Grease proof paper2. Kraft paper3. Pouch papers4. Cardboard

PULPING METHODS

MANUFACTURING OF PAPER: Raw material preparation Pulping Bleaching Stock preparation sheet formation Consolidation drying Finishing Pulping methods can be divided into :1. Chemical pulping 2. Semi-chemical pulping3. Mechanical pulping

BLEACHING OF PAPER

Only required in those grades where higher brightness level is desired.

Common bleaching chemicals used are- chlorine and hypochlorite.

BRIGHTNESS OF DIFFERENT PULPSType of pulp Brightness (%)

UNBLEACHED SULFATE 20-45BLEACHED SULFATE 70-85UNBLEACHED SULPHITE 50-65BLEACHED SULPHITE 75-85SPECIALLY PURIFIED PULPS

UPTO 90-94

GROUNDWOOD 55-60

PAPER MAKING Suspension of the fibre from its suspension in

water Removal of water occurs by gravity and then

vacuum is applied. Next, in the press section 42% dryness is

removed Followed by water removal in a battery of

steam heated drying cylinders. Lastly it is passed through a calendar to

remove uneven surfaces

Grease proof paper:1. Use in packaging of butter, margarain

etc.

Kraft paper:1. Also know as unbleached heavy duty

paper.2. Mostly used for printing containers.

Pouch papers:1. Made up of special kind of laminated

paper.2. Smooth surface3. Used for packaging of

coffee,dehydrated soups,milk foods etc.

Cardboard:1. Made of sulphate pulp for packing

ice-cream etc.2. The pulp gives it water and oil

resistance.3. Other types include glazing type

paper made of long wood pulp for imparting physical strain.