Lezione 9: Flexible plastic materials for food packaging Flashcards
On what is foock packaging developed and designed on?
- functional performance required by food
- packaging equipment used & customer production process
- regulatory requirements
- sustainability goals
- convenience needs of final consumer
- information & communication / branding
What are the main groups in which to classify food spoilage?
- Physical spoilage: change in water content, change in texture
- Chemical spoilage: oxidation of lipids, pigments and vitamins; browning, in which colourless compounds are converted into brown colored ones because of enzymes chemical reaction; heat and light are catalyzers of degradation
- Microbial spoilage: bacteria, yeasts and moulds spoil food by growing in it and producing substances that change texture, c color, odor and taste of the food.
What is shelf life?
Shelf life specifies the period of time which a product can be stored, under specified conditions, and remain in optimum condition and suitable for consumption = no spoilage
What is the effect of atmosphere on food?
Atmospheric gases are inert for food except for:
- Oxygen: Key role in oxidation reactions and growth of aerobic microorganisms. Necessary for breathing stuff or for meat blooming.
- Carbon dioxide: At concentration >20%: inhibitory effect on spoilage caused by microorganisms.
What are the 2 solutions for atmosphere managing in food packaging?
- Vacuum package: a package from which the partial pressure of atmospheric gases has been reduced. In order to maintain vacuum, a package must be hermetic and made of materials which limit the permeation of gases.
- MAP packaging: a package with head space where, following air elimination, a gas mix is injected.
Gas used are: CO2 (20-30%), bacteriostatic; O2 (40-80%), bright red color in red meats; N2 as balance, inert.
Air: SL 3-5 days
MAP: SL 7-10 days
Vacuum: SL up to 30 days.
What kind of packaging machines are used for food?
- Overwrapping machines - HFFS: solid food, flexible materials, consumer units, Horizontal packing
- Overwrapping machines – VFFS/VPP: solid or liquid-solid food, flexible materials, costumer and industrial units, vertical packing
- Thermoforming machines – THF (MAP or VACUUM): solid or semisolid food, flexible top and rigid bottom, consumer and industrial units, horizontal packing
- Tray sealing machines (MAP or VACUUM): solid or semisolid food, flexible top and rigid premade bottom, consumer units.
- Bag loading, vacuum sealing & shrinking machines: solid food, flexible skrinkable material, consumer and industrial units.
What kind of processes do in pack foods go through for further prolonging shelf life?
- Heat Pasteurization: foods are treated with mild heat, usually less than 100 °C, to eliminate pathogens and stabilize foods by destroying or inactivating organisms and enzymes. After this food is kept in refrigerated conditions.
- Heat Sterilization: foods are treated with stronger heat, usually from 100°C to 130°C, to completely eliminate all living micro-organisms. After this food can be kept at ambient conditions.
- Cooking-in-the pack: for both industrial and consumer level.
Which framework regulations does Europe have?
- 1935/2004/EC: defines all requirements for Food Contact Materials but only for plastics, ceramics and cellulose regenerated. General requirement: shall be manufactured in compliance with good manufacturing practice so that they do not transfer their constituents to food.
- 10/2011/EC: Rules for overall Migration Testing; Positive list of chemical substances admitted; Special rules for the use of post consumer recycled plastics.
What is the definition of sustainable development?
Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.
What is the EU strategy for Plastic in a Circular Economy?
By 2030, all plastics packaging placed on the EU market is either reusable or can be recycled in a cost-effective manner.
55% of plastics waste generated in Europe is recycled by 2025
What kinds of recycling are used mainly?
- Mechanical recycling: plastic waste is milled and washed, passes a flotation separation, and is dried. The plastic flakes are then either used directly to produce new plastic materials or they are processed into granulates beforehand. Preserves the molecular structure.
- Chemical recycling: pyrolysis and gasification, which are used to turn plastic polymers back into individual monomers.
What is Carbon Foot Print?
La carbon footprint (letteralmente, “impronta di carbonio”) è un parametro che viene utilizzato per stimare le emissioni gas serra causate da un prodotto, da un servizio, da un’organizzazione, da un evento o da un individuo, espresse generalmente in tonnellate di CO2 equivalente.
What are the main convenience needs applied to food packaging?
- Small portions / easy opening
- Reheat in pack
- Cook in the pack (up to 200°C, easy to open)
What are the main elements for communication and branding?
- Color: Some retailers decide to associate a specific color / pantone to their private label products
- Print: inform, communicate, attract
What are the main polymers used for food packaging production?
- Mechanical: PE, PP, EVA, PA, PS, PET
- Barrier to gas: EVOH, PA, PET
- Sealing/opening: PE, EPC, EVA
- Thermal resistance: PP, PET, PA
What are the additives that are added to polymers for packaging?
- Antifog: Prevent Water Droplet Formation
- Antistatic: Minimize Static Buildup and discharge
- Slip agent: Lower Coefficient of Friction
- Antiblock agent: Prevent Self Adhesion, Enhance slip
- Color: Product Identification, Differentiation
- Plasticizer: Easier processing (polymer orientation)
- Compatibilizer: Compatibilize different materials
What are the layers composing a multilayer structure?
- Skin/sealant layer: SEALABILITY or EXTERNAL PROTECTION
- Tie layer: ADHESION BETWEEN LAYERS
- Abuse layer: ENHANCED MECHANICAL RESISTANCE
- Core layer: BULK OR BARRIER PROPERTIES
How is a multilayer structure produced?
- Coextrusion
- Lamination
Why is orientation important and how is it obtained?
It is obtained by applying a controlled stress (LD and TD) to the polymeric material, after having heated it at a certain temperature, necessary to achieve chain mobility.
Give shrink properties to the material, since orientation is reversible: by re-heating the material, it has a tendency to return to its original configuration
Increase mechanical properties of the material due to polymeric chains alignment in the direction of orientation
What is active packaging?
Defined as materials that are intended to extend the shelf- life or to maintain or improve the condition of packaged food; they are designed to deliberately incorporate components that would release or absorb substance into or from the packaged food or the environment surrounding the food
What is intelligent packaging?
Materials and articles which monitor the condition of packaged food or the environment surrounding the food; intelligent packaging systems provide the user with information on the conditions of the food.
