Sustainable Food Packaging
packaging methods, material and sustainability
packaging methods, material and sustainability
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Flashcards
PVC (Polyvinyl chloride)
+low water vapor permeability
+chemical, oil and fat resistant
- environmental debate but in comparison to PP and PE more environmental
For bowls and cups
PVDC (Polyvinylidene chloride)
+transparent
+ very low permeability to gases water vapor and aromas
- environmental debate
Barrier behavior depends on the relative humidity
Wide application range
PA (Polyamide)
+Good mechanical properties
+chemical resistance
-Barrier behavior depends on the relative humidity
EVOH (Ethylene vinyl alcohol copolymers
+transparent
+good oxygen barrier
+- middle water vapor barrier but strong dependence on relative humidity
only in composite materials in use
PLA (Polylactic acid)
+biodegradable (compostable)
+crystal clear
+comparable to traditional thermoplastic
-relatively high gas and water vapor permeability
For food packaging with a short shelf life
Natural products (ham in networks, sausages in guts)
+Good design and shape retention
+looks traditional produced
-Hardly product protection
-Risk of friction and pressure losses
Cellulose
+extremely universal due to chemical modification
+good gas barrier
- poor water vapor barrier (hydrophil)
mainly from wood
Starch compounds
+good gas barrier
+addition of starch improves biodegradable ability
100% starch polymers are 100% compostable
-poor water vapor barrier (hydrophil)
Used as thermoplastic for bags, coating of paper
PEF (polyethylene furanoate)
+better water vapor and gas barrier than PET
+reduction of material possible
+ good thermoformable
+good mechanical properties
+100% plant based (maize wheat chicory are recyclable
-non biodegradable
For bottles
PBAT (polybutylene adipate terephthalate)
+industrially
+compostable
+mechanical properties same like PE LD
-poor water vapor and gas barrier
For shrink films and mulch films
PHA (polyhydroxyalkanoates)
+high gas barrier
Not transparent
+UV light resistance
-low water barrier
-high costs
-fragile
-limited workability
For containers films and coatings
PBS (polybutylene succinate)
+ hydrophobic (good water vapor barrier)
+biodegradable
+good thermal properties
-poor oxygen barrier but better than PE
Proteins
+good gas barrier
+biodegradable
-Low water vapor barrier
Made from whey protein
Waxes and fats
+high gas and water vapor barrier
-biodegradable
Coating for fruit & vegetables
Which processes in food deterioration are given?
microbiological = aerobe with oxygen and anaerobe without oxygen
chemical / biochemical = fat oxidation, light influence -> oxygen, enzymatic browning -> oxygen
physical = loss of water, uptake of water, off-flavour, loss of flavour
Which wavelength cause problems for highly unsaturated fats and oils?
The visible light for oleic acid and linoleic acid between 300 and 550 nm
What we have to consider if we design a packaging?
- Gas permeability of the used packaging materials is essential in designing the packaging
- Storage conditions (temperature, humidity, light) to be considered inpackaging design
- Seal seam defects have to be avoided
- Active packaging concepts are promising especially for meat and sausage
Meat packaging Layers pork and chicken ?
and Gas distribution!
Tray = Polypropylen
Lidding film = PET-PE-EVOH-PP -> multilayer
70% oxygen
20% CO2
10 % nitrogen
BOPP (biaxial oriented Polypropylen) has a low water vapor permeation of 0,6 but a high oxygen permeation of 200. We want to design a Snackbag how can we use this material with fitting the oxygen permeation of 1?
We can spray a thin aluminum layer on it with a nanocoating technique. In this case we can reduce the oxygen permeation to 1 and also reduce the impact of light.
How can you calculate the oxygen or water vapor value Q which go through the Barrier
Q = P/d
P = Permeation koeffizient of the given material
d = diameter
In general it depends on the thickness, if we double the tickness of the material we halve the oxygen and water vapor permeation
Preparation Method flat film extrusion?
1. Extruder feeding with plastic granules
2. Feed block and flat film extrusion die (Düse)
3. Chill-Roll for cooling with thinkness controll
4.Winding unit
5. Control System at the end
Preparation Method blow extrusion technique?
1. Extruder filling with granules
2. molding in the Ring nozzle (Düse) then cooling by air or water and
3. Calibration
4. Thickness measurement
5. Flatness unit
6. Baffle (Leitblech)
7. Winding unit
Coextrusion preparation method
Flat or blown film extrusion can be used. Different material types are molten and processed to one film.
Combination Example (PA/EVOH/PE)
Extrusion coating or laminating?
Combination of a prefabricated film with another film (heat sealing film)
Conglutination of the film web(s) with the melt under pressure
1. Extruder
2. Pay off reel
3. Radiant ring die prepreparation
4. Lamination
5. Thickness measurement
6. Rewind
Stretching unit?
1 Film processing, film extrusion
2 Film heating treatment
3 Biaxial strechting
4 Annealing or glowing (glühen)
5 Control systems
6 Winder
Increasing the strength, gas barrier, surface quality, transparency and gloss;
Boat evaporator for aluminum Steam
- Evaporator for metals (Al) can increase the barrier of a material for Instant a BOPP (Biaxial oriented Polypropylene) with Aluminum reduce the oxygen permeation by the factor 200
1. pre vacuum area with the material (FOr instance BOPP)
2. thickness control
3. high vacuum area with the aluminum evaporater
4. cooling roller
5. winding roller
Thermoforming device
1 Unwinding
2 Film heating treatment with IR
3 Deformation by stamp and / or
compressed air and / or vacuum
4 Filling
5 Cover film winding
6 Sealing / sterilization / vacuum / gasing
7 Stamping
1 Abwickeln
2 Folienerwärmung mit IR
3 Verformung durch Stempel und / oder
Druckluft und / oder Vakuum
4 Füllen
5 Aufwickeln der Deckfolie
6 Versiegelung / Sterilisation / Vakuum / Begasung
7 Stempeln
Bag forming, filling and sealing machine
1 Film roll
2 Film guide
3 Hopper (EInfülltrichter)
4 Filling pipe with forming shoulder
5 Off belt
6 Longitudinal sealing
7 Cross seal and punching knives
8 Finished bag
Which packaging problems can occur?
• Buckling (Bombage, Ausbeulung) -> improper gassing (to much N2) too high product activity
• Collapse -> improper/incorrect gassing (to much CO2)
• Mold growth -> incorrect packaging material
• Growth of anaerobes -> too dense packaging, nonsterility
• Gray flesh color -> Permeability is too low / too high (fresh meat)
What´s the better choice buying the packed or the unpacked cucumber?
It depends because we have a high consumption in Germany in this case we buy all cucumbers before they rotten.
In general, it is more sustainable if we pack it because we have a lower food waste due to increase the shelf life. PE shrink film monolayer. But if we have a paper on top then it detected as a mixed layer and it will burn and not recyle in the PE stream.
Which permeation analytics you know?
Gravimetric method, Electrolysis method and oxygen sensors
Mechanical Testing measure Methods?
Tensile strength Zugfestigkeit
ultimate elongation Bruchdehnung
Slide friction Reibung beim gleiten
E-modul,
Bending test, Biegetest
Adhesion Haftung
Seal strength Festigkeit der Dichtung
Thightness of packaging measure?
Rhodamin test,
vacuum chamber
headspace gas analysis
and the helium leak detection device
How to identify packaging materials?
With the differential scanning calorimetry (measure the amount of heat release by heating and cooling.) + infrared Spectroscopy in combination with an microscope
Nuts or Snack packaging ? What we can use for materials?
what is the storage time?
ingredients? fat and oil (unsaturated) -> fat autoxidation -> rancidity
What to do? prevent the crisps from oxygen, water barrier to pretend the crispy and a light barrier.
Here we have the task to combine different materials with different properties to a multilayer
Cobine BOPP with aluminum coextrusion to guarantee the oxygen, water vapor and light barrier.
Otherwise we can cobine PET for Printing + EVOH for oxygen barrier + PP for water vapor Barrier
Oxygen Barrier Measurement?
With a Oxygen Sensor
1. First, a carrier gas is injected after that the gas go trough a
2. Humidificator
3. then trough a catalyzer
4. Into a Measureing cell and through a cappilar into the packaging
5. on the other side of the packaging is an electrochemical sensor cell
Water vapor analysis?
Carrier gas is fed into a chamber via a dry filter cartridge.
The chamber is separated by the sample material.
One side has 0 % humidity and on the other side we have 85 % room humidity.
An electrolysis cell is connected to the chamber outlet and evaluates the data.
Rhodamin test
The Contrast medium visualize pores optical
con : destroying test
pores >30 micrometer
Vaccum chamber
pro: localisation of defects with vaccum and water -> occuring bubbles by pores
con: packaging is getting wet
measurement range pores >15 micrometer
Headspace gas analysis -> Detection of O2 and CO2
pro: it is a fast measurement and results can be statistical visualized
good measurement range from 0 till 100 %
cons:
The required time interval between filling
and measurement depends on the size of the hollow spaces