Materials For Food Packaging Bhavana Rao (11BCH0013) K Yesaswini (11BCH0023)

INTRODUCTION: Packaging in some form has been in existence for centuries. The growth and its usage has been particularly rapid in the second half of the 20th century over the world. Packaging is now generally regarded as an essential component of our modern lifestyle. Today, packaging is produced more quickly and efficiently than ever before. It has evolved from a relatively small range of heavy rigid containers made of wood, glass or steel to a wide array of semi rigid and flexible packaging options increasingly made from specialized light weight materials.

SIGNIFICANCE OF PACKAGING: Serves the essential function of containing food. Protects it against physical and chemical damage during transportation and distribution, varying climatic conditions (heat, cold, moisture, etc.), hazardous substances, infections and micro organisms. Protects the form, shape and texture of the food inside. Prevents the loss of flavor and odor, thus improving the product shelf life. Serves as an important medium where by manufacturers can provide information on ingredients, nutritional contents and other product features.

COMMON PACKAGING MATERIALS: GLASS Commercially-available glass is made from silica, sodium carbonate and calcium carbonate. Other compounds can be added to give colour, sparkle or heat shock resistance. Glass is a popular and useful packaging material because it is: Inert Sterilisable Barrier to moisture and gas Pressure resistant to a degree Can be moulded into a variety of shapes Transparent making the product visible Glass is also highly recyclable The most obvious drawback is fragility and the danger of broken glass. The transparency of glass can be a problem where the product is degraded by light.

METALS The metals used in packaging are predominantly tin-plate or aluminium and are used to make food and drink cans, aerosol cans, tubes, drums and slip or hinged lid boxes for gift sets and selections of confectionery or biscuits. All packs are recyclable. Tin-plate is tin-plated steel and the most common material used in food cans.  Steel can also be used un-plated or with coatings. Aluminium is used for drinks cans, closures, trays, tubs and tubes. As foil it can be used in multi-laminate constructions or as a blister pack or container seal. Metal can be exploited to produce the following packaging characteristics: Strong and rigid Barrier to gas and moisture Pressure resistant Temperature and pressure resistant / tolerant Corrosion resistance via coatings Sterilisable Directly decorated or labelled The limitations of metal packaging are in weight and shapes achievable, especially when compared to plastics.

PLASTICS Plastics can be used as single materials or in combination. Their properties vary considerably but usually include: Lightweight Easily mouldable into almost limitless shapes Can produce rigid containers or flexible films Can be impact resistant Directly decorated or labelled Heat sealable The relative disadvantages of plastics are typically polymer specific and the correct choice of polymer can to a practical degree mitigate the weakness. 

Material Use Appearance Properties Temp. Tolerance Polypropylene Most common takeout packaging material. Excellent for ready-to- heat Usually black or clear. Very rigid, crack resistant. Can resist 220o-240o C. OPS/HIPS Versatile because one SKU can be used for sandwiches, salad, bakery produce and catering. Popular for platter domes. Crystal clear. Stiff but brittle. Offers superior leak resistance. Best for cold and room temp. Withstands up to 150oC. Foamed Polystyrene Clamshells and other hinged lid containers, tableware, etc. Used for coffee and other hot beverages. Can be white, black, yellow or blue. Excellent heat retention and cold insulation. Moderate. Microwaveable. CPET Frozen dinner trays and takeout containers that need to be heated. Often black, can be in other colors as well. Good crack resistant when frozen. Design flexible. Wide range of -40o- 400oC.

POLYPROPYLENE CPET FOAMED POLYSTYRENE OPS/ HIPS

Materials Use Appearance Properties Temp. Tolerance Foamed Polypropylene Good for clamshells and other hinged-lid containers. Usually white. Excellent heat retention and cold insulation Can hold hot foods and microwavable. PVC PETE Especially good for cold foods, drinking cups, frozen foods. Extremely high clarity. PETE can be colored. Durable, tough and clear. Moderate temp. resistance. starts to melt before 140oC Molded Fiber Plates, beverage carriers, fruit trays, etc. May be white or grey depending on the amount of recycled paper. Superior strength, can be made to absorb grease from fried foods and prevent soak through. Can be microwaved. Not for use in conventional oven. LDPE Used for flexible tubes, film and some bottles. Usually clear. flexible, moisture protection, tough, chemical resistance, Low melting point BOPP Used in films for packaging of chips, biscuits etc. Low density, improved mechanical strength compared to polypropylene

MOLDED FIBER FOAMED POLYPROPYLENE LDPE PVC/PETE

COMMON PACKAGING METHODS Vacuum Packaging : It’s a method of packaging that removes air from the package prior to sealing. The main intent is usually to remove oxygen from the container to extend the shelf life of the foods and with flexible packaging forms it reduces the volume of the package. mainly used to store cereals nuts curd meats cheese smoked fish and coffee. Aseptic Processing: It is the process in which the sterile product is packaged in a container in a way that maintains sterility. It is a flash heating process which retains more nutrients and uses less energy than conventional sterilization techniques like hot fill canning. It allows the processed product to keep for a long period of time without preservatives as long as it is not opened. the aseptic packages are typically mix of paper (70%) poly ethylene (24%) and aluminum (6%). Together these materials form a tight seal against micro biological organisms contaminants and degradation thus, eliminating the need for refrigeration. This method is mainly used for packaging of milk and milk products, fruit juices, etc.

Canning: is a method of preserving food in which the food contents are processed and sealed in an airtight container. Canning provides a shelf life typically ranging from one to five years, although under specific circumstances it can be much longer. Canning is a way of processing food to extend its shelf life. The idea is to make food available and edible long after the processing time. Studies have shown that canned fruits and vegetables are as rich with dietary fiber and vitamins as the same corresponding fresh or frozen foods, and in some cases the canned products are richer than their fresh or frozen counterparts.

We have a wide range of packaging materials so why do we need better packaging materials???

EXAMPLE 1: Starbucks sells 4 billion paper cups annually, and most of them are never recycled. "Recycling seems like a simple, straightforward initiative - but it's actually quite challenging," the company said in a recent statement. 1. The cups have a plastic lining that prevents leakage, but is difficult and costly to remove. "Recyclers will only bother [to remove the lining] if they are supplied with enough used cups to justify running the process on a regular basis," Minter writes. 2. Starbucks can't provide enough cups to justify the costly recycling process. A pilot program in 2010 collected three tons of cups from 170 Toronto stores. But that was only a tiny fraction of the 51.5 million tons of recyclable paper products collected in the U.S. that year, according to Minter. 3. Composting isn't a great option either, even though it would keep the cups from ending up in landfills. Composting "generates greenhouse gases while destroying the recycling value packed into the cup's fibers," Minter writes. 4. Starbucks has failed to get customers to start using personal reusable cups. The company set a seven-year goal of serving 25% of beverages in reusable cups by 2015. In 2011, just 1.9% of beverages were served in those cups.

EXAMPLE 2: Why does bottled water have an expiry date?

These dates are helpful because the flavor of the water will change over time as it absorbs chemicals from its packaging. The flavor will not necessarily be bad, but it may be noticeable. Leaching of chemicals from packaging is a health concern, but as far as toxic chemicals go, you can get exposure to most of those chemicals from freshly bottled water as well as bottled water that has been on the shelf a while. The materials used for making these bottles consist of compounds such as formaldehyde which are categorized as carcinogens.