Food Packaging & Labeling farooq@asab.nust.edu.pk

Aims Packaging is a critical component of food products. It protects the product and preserve its quality. Prevents physical damage e.g. knocking, shaking or crushing Prevent contamination from microorganism/ pollution Protects against dehydration and dampness Barrier protection Extend the shelf-life of foods Convenience Consumer information Attraction

Protection The aim of packaging is to contain the product and keep it intact. This means that liquid products do not leak and that dry materials, such as flour, do not spill out. It is sometimes necessary to design packaging that is shaped especially to contain a particular food, e.g. egg boxes, so that the product is held securely and well protected from damage.

Labelling Packaging is also designed to be visually stimulating and provide information about the product to help the customer. The information supplied must cover: • the name of the food; • the weight/volume (metric) (unless under 5g); • the list of ingredients in descending order of weight; • how the food should be stored, where appropriate; • the date when the food should be eaten; • genetically modified ingredients and allergens; • the name and address of manufacturer or distributor; • nutrition information on the back of pack (from 2016 onwards).

Consumer information Food assurance schemes have been developed to compliment food legislation. They cover the food chain from farm to fork: cereals, oilseeds, pulses and sugar; fruit, vegetables and salad; milk; chicken; beef, lamb meat.

How does packaging attract customers? Packaging is used as a way of attracting customers to the product in place of the shopkeeper. This is done by using: enticing adjectives to describe the product such as moist, sweet and creamy colourful packaging a photo of the product

Barrier Packaging There are two basic reasons for using barrier material for product packaging; to keep desirable elements in (such as flavor, aroma or a controlled atmosphere), to keep undesirable elements out (such as moisture, oxygen or other corrosive gases). Barrier Packaging is used to keep food fresh, prevent corrosion or rust, extend product shelf life and provide long term preservation.

Packaging Materials Cans Paper, board, foil Plastics Cellulose Films Glass

Polypropylene is used

Packaging Components Plastic packaging materials has increasingly replaced metal and glass for food and beverage packaging

Advantages of plastics: lower costs, lighter in weight, less apt to break or shatter, transparent, flexible, direct food contact without changing sensory properties, can be reheated in micro-wave (versus metal) general consumer preference because of convenience

Disadvantages of plastics: high gas and water permeability; absorption of food/beverage flavour; low heat resistance (many foods require pasteurisation or sterilisation); not tough enough (brittle); poor appearance; migration of low molecular weight compounds (e.g. monomers).

MIGRATION In food packaging the term MIGRATION is generally used to describe the transfer of substances from the package to the food. Substances that are transferred to the food as a result of contact or interaction between the food and packaging material are referred to as migrants.

Migration is a two-way process because constituents of the food can also migrate into the packaging material. Example: “Scalping” of flavour compounds from fruit juices by plastics. Also compounds present in the environment that surrounds the packaged food can be absorbed by the packaging and migrate into the food. Example: perfumes from soaps can be picked up by fatty foods under certain circumstances e.g. on the nature of the packaging materials used for the soap and the food , time of exposure

Polyolefin Polymer materials for food packaging The most widely used polymers for food-packaging polyethylene and polypropylene They are used in direct contact with food since they are chemically inert, thermo-stable and provide an excellent moisture barrier. They are used either alone, or as the innermost layer of high barrier packaging structures, like polyethylene laminated aluminium cartons.

Polyethylene CH2 ----- CH2 n Polyethylene is the most popular plastic in the world. This is the polymer that makes grocery bags, shampoo bottles, film, milk bottles, and children’s toys. Polyethylenes are extremely tough, flexible, and chemical resistant. However, their heat resistance, and load bearing capability are limited. For such a versatile material, it has a very simple structure, the simplest of all commercial polymers. PE formed from the polymerisation of ethylene

Molecular structure of PP. Polypropylene Polypropylene’s (PP) chemical structure is very similar to PE, however, on each second carbon atom in the backbone a methyl group is attached CH2----- CH CH3 n Molecular structure of PP. These methyl groups greatly restrict molecular rotation and flexibility, resulting in significantly greater stiffness than PE.