COURSE TITLE: FOOD PACKAGING COURSE CODE: FST 509 COURSE UNIT: 3 UNITS COURSE LECTUTERS: DR. M. A. IDOWU AND MRS. G. O. FETUGA LECTURE
1 1.0 PACKAGING Is the use of containers and components plus decoration or labeling to (i) Protect (ii) Contain (iii) Identify (iv) Merchandise (v) And facilitate use of products. One or a combination of these elements may be involved. Today virtually every manufactured or processed food product required packaging in some phase of production or distribution. Increasingly this packaging function requires specialized skills, machinery and facilities to produce packages that meet one or more of four basic demands 1. To make it easier and safer to transport 2. To protect the product against contamination or loss 3. To protect against damage or degradation 4. To provide a convenient means of dispensing to the exterior The Addition of printing or other decoration to the exterior of packages serve (a) To identify the contents as to types and quantity (b) Identify the manufacturers brand and quality grade
(c) Attract the buyer’s attention (d) Persuade buyer to purchase (e) Instruct purchaser on how to use the product BACKGROUNG: Food containers and their utilization go back to the dawn of history. Food items to be stored or transported called for packaging. May different things were used · Leaves · Hollowed-out plant limbs · Gourds · Skins · Reed Baskets · Earthenware vessels In time containers were improved or developed to meet the special needs of nomadic tribes · Agragrians · Merchants, traders and even for religions and war The antecedents of some modern containers such as glass bottles and certain pactaging practices like lebelling are very old. Glass bottles were used in Egypt more than 4,000 year ago. Marks and signatures, symbols and seals of various types appeared on the very first glass bottles used in commerce. The carliest paper originated from China about 200 B.C. Egyptians and Greeks used it about 500 B.C. and the Arabs learned the art from the Chinese during the Chinese invasion of 751 AD.
The tin can owes its origin to the discovery in 1200 AD by Bohemian artisans of a hot dip process for plating tin onto thin sheets of iron. The Romans used lead in many ways including water pipes and ointment jars. Until about 1800, the making of packages was a craft or an art. It was the industrial revolution which produced advances in containers invention and fabrication resulting in the container forms we are familiar with today. · Metal cans · Glass jars · Collapsible tube · Folding Carton · Corrugated shipping case · And crown caps for bottles. During the latter part of the 19th century into the early part of the 20th century, the groundwork was laid for mechanized production of all standard container forms. Simultaneously with this, linotype, photoengraving, process colour-printing and several graphic-art processes were developed thus completing the combination of container + effective decoration which has made modern packaging possible. Between 1900- 1930 several revolutionary products were discovered: · Glassine · Kraft paper · Cellophane · Aluminium foil These provided the basis for a whole new development in
FLEXIBLE PACKAGING The search for new materials thus stimulated by these discoveries has lead to spectacular discoveries since 1940 when · Polyethylene · Polyester · Polypropylene · Stretchable paper · Steel foil · Ionomers and a host of improved, coated or · Laminated materials were introduced Development of sophisticated merchandizing techniques was occurring parallel to that in packages making. It is these two mutually related factors which lead to the flood of packaged products that has never stopped growing in volume and variety. We are now in the era of CONVENIENCE PACKAGING. Right along with these developments, machinery has been evolved for all phases handling, filling, closing, labeling and shipping of packaged products. Lines of machinery tailored to the needs of every conceivable food product and any type of container can be found. A new science of packaging management and packaging methods has been born.
LECTURE 2 2.0 MODERN PACKAGING MATERIALS AND PACKAGE FORMS 2.1 A RIGID PACKAGING MATERIALS AND PACKAGE FORMS 2.1.1 GLASS CONTAINERS Glass = Limestone + Sand + Soda Ash + Alumina Colorants may be added to the melt or introduced later ADVANTAGE · It is strong, rigid, chemically inert · It is an excellent barrier against solids, liquids and gases · It does not deteriorate appreciably with age · It is low-cost (7/1b in finished delivered container) · Its transparency (gives excellent product visibility) · Attractive finishes of a variety of types are possible · Extremely versatile, as to size and shape DISADVANTAGES · Weight – heavy · Fragility in transport, Not easy to dispose of
2.2 TYPES OF GLASS CONTAINERS (i) (ii) (iii) (iv) (v) (vi) BOTTLES JARS TUMLERS JUGS CARBOYS VIALS & AMPOULES Shape High Wide- Open- Large Heavy Small container Uses usage monthed ended No sized shipping principally for narrow short- necks at all Bottles containers pharmaceuticals, necks necks Jams & with shaped like Spices, food large liquids Jellies handle short colorants bodies solids short necked liquids or semi- narrow- bottles 3 small size liquid necks gallons & solids sauces & used for larger pastes liquids capacity in ½ used with gallon wooden & larger crate sizes Holder & of the protective frames
2.3 CONSIDERATIONS IN CHOOSING GLASS CONTAINERS FOR FOOD DIMENSIONS AND “FINISH”:- Ensure that volume is adequate product is easily filled and dispensed Proper closure can be selected “FINISH”:- Refers to type of and dimensions of neck and mouth of container i.e THREAD, LUD, FRICTION, SNAP-ON, ROLL-ON Many standard finishers are listed by the glass containers manufactures institute COLOUR:- Influence type of light reaching the food ABILITY TO RESIST THERMAL SHOCK:- This is important in heating and cooling operations. LECTURE 3 3.0 METAL CANS Consists of steel base sheet with a tin coating. The tin is applied by hot dip or electrolytically. Electrolytic application can be done differentially so that the two sides of the tin plate have different thickness of tin coating. 3.1 LAQUERS, Enamels Besides the tin coating other organic coatings are also applied. These coatings must be non-toxic and free from odors and tastes. They must not come loose during processing or storage
These coatings consist of INTERIOR EXTERIOR Acrylics Acrylics Alkyds Alkyds Butadienes, epoxyamine Oleoresins Epoxyester, epoxy-phenolics Phenolics Oleoresins, Phenolics Vinyls Vinyls Since 1959 – Aluminum is being used for beers, concentrated frozen fruit huice, frozen baked goods, powdered mil, condensed milk. An interior coating is generally necessary for Aluminum. Advantages of metal cans Disadvantages 1. Strong 1. Heavy 2. High speed manufacturing, filling and 2. cannot be re-closed closing 3. Not disposable 3.2 COMPOSITE CONTAINERS This is made from 2 or more constituent materials Usually = Paper Board Body + Metal or plastic Ends Two types:
(a) Spiral wound containers – made in cylindrical shapes where two or more plies of board are glued together around a mandrel (b) Convolute – wound composites – produced by straight winding. 3.3 AEROSOL CONTAINERS Uses Beverage concentrates Cocktail mixes Cake icings Pancake mixes Syrups Salad Dressings and seasonings 3.4 RIGID PLASTIC PACKAGES Advantages · Low cost · Ease of Fabrication Disadvantages · Lack of product compatibility · Low barier properties · Plastic deterioration · Low heat resistance · Fragility at low temperature. 3.5 MAIN TYPES OF PLASTIC CONTAINERS Thermoformed Injection-Molded Blow-Molded Heart treated plastic is Used in high volume Used where containers have
formed around a mold. applications for jars bottles small neck diameter They may be pressure or and tubs. Plastics used are: compared with rest of body. vacuum formed. polypropylene, polystyrene. Plastic used are: Polyvinyl Plastics used are polyvinyl Has outstanding clarity chloride polypropylene, chloride polystyrene, poly- polycarbonate, Cellulose propylene ABS Acetate Polystyrene (Acrylonitrile butadiene polyethylene, polyacetate. styrene) Cellulose acetate. Trays are made with – this method 3.6 SOLID AND CORRUGATED FIBERBOARD CONTAINERS Used to fabricate shipping cartons and cases Used in wholesale and industrial shipping. 3.7 WODDEN BOXES AND CRATES Used when timber is plentiful and inexpensive for shipping purpose. 3.8 CYLINDRICAL SHIPPING CONTAINER Have high stacking strength Can be rolled in Handling They are made from fiberboard Glass, metal, plastic or wood Glass containers have been used as liners for other shells from: steel aluminium, fiberboard or wood
BARRELS Metal barrels made of steel or aluminium DRUM PAIL KEG Small barrel CASK Large, light wooden barrel 3.9 CONTAINERIZATION Purpose is safe transport of goods from point of manufacture to sales point economically. Concept is to use as freight, container which is delivered directly to factory from loading point. At point of use container is directly off-loaded. LECTURE 4 4.0 SEMI-RIGID PACKAGING MATERIALS AND PACKAGE FORMS 4.1 ALUMINIUM CONTAINERS Advantages Disadvantages 1. Convenience in preparation and High cost as at now high technology of serving of food. They withstand high capital intensity. high temperature foods can be frozen in packages or cooled in it. 2. Protects food as an excellent barrier 3. Very Light Types: Folded end Ovals
Pie Plates Rectangular Rounds Squares Specialty Items 4.2 SET-UP PAPERBOARD BOXES Four Basic components (i) Paperboard (ii) Adhesive (iii) Coner Stays (iv) Covering Advantages : Convenience Individuality Strength Reusability Excellent Protection Disadvantage: High cost 4.3 FOLDING PAPERBOARD CARTONS 4.4 MOLDED PULP CONTAINERS LECTURE 5 5.1 METAL CANS
More than 49 billion metal cans are manufactured in the U.S. annually. This accounts formore than 30% of all units of consumer packaging. The tin container was invented in 1810 by Peter Durand an English man. It was introduced to the U.S. in the 1820’s. At that time cans generally were made by hand. They were made during the winter months for use along with the next harvest. An expert can maker would produce 5 or 6 cans/hour. “Sanitary” can was developed about 1900. This paved the way for mechanization. The Metal Box Company is the only producer in Nigeria. At the moment they are making mainly No Al-type Cans. The total quality of cans manufactured are probably very much below the 10 million mark. 5.2 TIN PLATE CANS Consist of a steel base sheet with a tin coating. (a) the steel base plate is usually about 0.01 thick (b) the tin coating has thickness varying from 15 x 10-6 inches thick (c) Can enamels (Laquers) are baked organic coatings which are applied to improve stability of can interior when susceptible to damage by food materials packed in it. The tin plate is an ideal material for food containers. Tin is not completely inert to all food. But corrosion and product chances are small if the proper choice of material is made. Among the many factors considered by can manufactures are: 1. Chemical composition and physical properties of base plate 2. Thickness of tin coating
3. Application of protective coating or enamels 4. Container construction 5. Relative corrosivity of the product to be canned. A large number tests are conducted prior to adoption of material. 5.3 A BASE PLATE This is low carbon steel. Metalloid content particularly of phosphorus, silicon are critical. Other trace metals of importance are copper, nickel, molyhdenum. The amount of these elements affect the corrosion resistance of the base plate. Four Basic types of metal are used and a 5th is used for beer can ends Element % Permitted Type L Type MS Type MR Type MC Beer End Stock Mn 0.25-0.60 0.25-0.60 0.25-0.60 0.25-0.60 0.25-0.70 Carbon 0.12 max 0.12 max 0.12 max 0.12 max 0.15 max P 0.015 max 0.015 max 0.02 max 0.07-0.11 0.10-0.15 Sulfur 0.05 max 0.05 max 0.05 max 0.05 max 0.05 max Silicon 0.01 max 0.01 max 0.01 max 0.01 max 0.01 max Cu 0.06 max 0.10-0.20 0.20 max 0.02 max 0.20 max Nickel 0.04 max 0.04 max No limit No limit No limit Chromium 0.06 max 0.06 max No limit No limit No limit Molybdenum 0.05 max 0.05 max No limit No limit No limit Arsenic 0.02 max 0.02 max No limit No limit No limit
5.4 CLASSES OF FOOD PRODUCTS AND TYPES OF STEEL BASE REQUIRED Class Food Characteristics Steel Base Rqd Most strongly corrosive Highly or moderately Acid Type L Foods Moderately corrosive Acidified vegetables, midly Type MR acid food products Type MC Midly corrosive Low acid foods Type MR Type MC Non corrosive Mostly dry and non Type MR processed products Type MC TERM BASE BOX: You will come across this term repeatedly. Originally Tin plate was sold in only one size sheet 14” x 20”, 112 sheets – 1 Base Box. Such a package contained 2 31, 360 in or 217.78 ft of surface. TIN COATING This is applied by either hot dip or by electroplating. Today only about 6% of all tin cans are made by hot dip which produce non-uniform tin coating. Electrolytic plating can be differentially applied so that the inside and outside surface have different thickness of tin coating. Hot dip – (1.25 1b/Base box) of tin Electrolytic – (0.52 1b/Base box) of tin ENAMEL COATING
These are baked organic coating, normally applied by roller to the flat sheet and are baked at temperatures below the melting point of tin. Their purpose (1) Preserve attractiveness of food in CAN (2) Improve interior (occasionally only) exterior of can (3) Increase shelf life of can (4) Coating may make it possible to use less expansive tin coating 5.5 GENERAL TYPES OF ENAMEL COATING Coating Typical Uses Type 1. Fruit Enamel Fruits requiring protection Oleoresinous from metallic salts e.g cherries 2. C-Enamel Corn, peas and other sulfur- Oleoresinous with bearing products, including suspended zinc oxide some sea foods pigment 3. Citrus Enamel Citrus products and Modified Oleoresinous concentrates 4. Sea foods Enamel Fish products and meat Phenolic spreads 5. Meat Enamel Meat and various specialty Modified epons with products aluminium pigment 6. Milk Enamel Milk, eggs and other dairy Epons products
7. Beverage CAN enamel Vegetable juices, fruit juice, Two-coat system with (non-carbonated) highly corrosive fruits, non- Oleoresinous type base coat carbonated beverages and vinyl top coat 8. Beer Can Enamel Beer and carbonated Two-coat system with beverages Oleoresinous or polybutadiene type base coat and vinyl top coat. 5.6 CAN MANUFACTURING Modern process is highly mechanized. Can bodies are formed at speeds as fast as 600 units per minutes 1. Interior Enamel and outside lithography if used are applied to flat sheets of plate 2. Coated sheets are cut into proper size for individual can bodies 3. “Body Blanks” are fed into bodymaker which notches, edges and curls the plate so that the opposite sides lock together 4. The four thicknesses of metal which meet at the side seam are “bumped” flat and soldered (tin solder) forming a cylindrical shell. 5. The flanger puts a flared rim on both ends of the can body 6. When needed, a second coat of enamel is sometimes sprayed into the formed can body 7. One end (bottom) is double-seamed into the can body and the can is tested under pressure.
CAN ENDS: Are stamped from enameled or uncoated sheets of plate which have been out into strips of proper size. The edge of the end is curled to form a groove. Into the groove, a heavy liquid rubber sealant is flowed. This gasket-like material, when dried, provided an hermetic meal in the double seam between body and end. One can end is double seamed at the factory. The second is double seamed by the packer. 5.7 CIRCUMFERENTIAL BEADS Those are used on large cans to provide strength. It increases resistance to rough handling and improves can ability to withstand paneling pressure. 5.8 QUALITY CONTROL CANS The can manufacturer assumes responsibility for quality of tin plate in finished product. Microscopic pores or flaws in the plate may expose base plate and accelerate corrosion. Micro examination is done. Tests have been devised for checking continuity of tin coating. 5.9 (a) Pickle Lag Test Detinned sample in immersed in HCl. The rate at which H is given off by corroding 2 plate is recorded. Good plate is attached at a content rate throughout the test. Poor plate is attached critically. (b) Iron Solution Value (ISV) This simulates reaction with a filled tin can. It measures amt. of iron dissolved from a tin plate specimen immersed for several hrs. in acid solution (c) Tin crystal size: test samples are etched for 10- 15 seconds in acid solution, to bring out the pattern of crystals on the plate large crystals are desirable.
LECTURE 6 6.0 FLEXIBLE PACKAGING MATERIAL These generally fall into two broad categories 1. Paper and 2. Films 6.1 PAPER – Consist of bonds, tissues, litho, krafts, glassiness parchment and greaseproof. PAPER TYPE MATERIAL WTS/3000ft2 USES AND FINISHES (i) Bands Uncoated sheets 20-70 1bs/3000 ft2 Wide variety of made of bleached finishers for chemical pulp printing. May have high degrees of wet strength etc. 2 (ii) Tissues Light wt paper made 8-20 1bs/3000 ft Wide variety of of semi-fully strength and bleached chem. pulp porosity. They may be glazed etc. use as wraps (iii) Litho Coated on one or 29-60 1bs Used in publication both side advertising Excellent printing properties used in beer labels
(iv) Krafts Very strong paper, 25-80 1bs Wide variety of made in bleached or strength available unbleached form they are porolls and roughly finished. They are sheap. Used in making cannister labels (v) Glassines Super calendered 15-45 1bs Have high chemical pulp sheet resistance to air and grease. Very strong, have smooth surface and glossy. Used for candy wraps (vi) Parchment Bleached chemical 15-27 1bs Good grace pulp stipped in resistance, good wet H SO strength used for 2 4 butter and magarine wraps (vii) Greese Proof Very much like parchment paper. 6.2 FILM
Definition: Thin flexble plastic sheeting having a thickness of 0.0100 inchor less. They are flexible as a result of manufacturing processes. 6.3 PLASTIC FILMS (i) Cellophane Originated as a brand name for a regenerated cellulose film. Transparent, somewhat elastic heat-resistant, water and oil insoluble film. Produced by precipitating viscose solution with ammonium salts. When dry, cellophane film is relatively GAS TIGHT, when wet it loans much of its imperviousness to gas. Its lowest rated property is lack of flexibility. It therefore breaks easily when used with dry products. Cellophane is often used with other plastic films in laminates. Cellophane to cellophane is not heat sealabl but it easily accepts heat sealable coating. Cellophane should be used immediately after exposure to high PV or immediately after exposure to low temperature. (ii) CELLULOSE ACETATES Closely resembles cellophane as far as most properties go except in two respects 1. Gas Transfer 2. Water Transfer Cellulose acetate is better in water transfer resistance than in GAS TRANSFER resistance. Because of its permeability to GAS it is suited for packaging certain fresh products such as fruits and vegetables. It is not used for meat because its transmission rate of water is high and shrinkage and surface drying of fresh meat will result.