1. Food packaging and use of stabilizers
ADVANCED BIO-FRIENDLY POLYMERS
Food packaging and use of stabilizers
Györgyi Szarka

2. Packaging materials Paper Metal Plastic: -PP -PET box -PS -PVC
-Polyesthers foil
-PE
light,
transparent,
unbreakable,
minimal use of material,
good gas and aroma closing,
valuable raw material
C. Silvetre et. al. Prog. Polym. Sci., 36, 2011, 1766.

3. Polymer additives FUNCTIONAL PROTECTING TYPICAL STABILIZERS
Plasticizer
Lubricant
Antistatic
Filler
Foaming / Crosslinking
Colorant
Flame retardant
PROTECTING
Heat stabilizer
Light stabilizer
Antioxidant
TYPICAL STABILIZERS
Primary stabilizers/ antioxidants:
Hindered phenols, aromatic amines
Secondary stabilizers / peroxide decomposers:
Organic thioesters, phosphites and metal-thiocarbamates
Chelating agent/metal deactivator:
Organic phosphites and hydrazides

4. Problem related to food packaging
Migration of additives
Chemical changes during processing
Health problem due to synthetic stabilizers
FOOD
FOOD

5. Strategies to avoid migration
Macromolecular stabilizer
grafting by chemical decomposition of 1,2,2,6,6-pentamethyl-4-piperidyl-acrylate (PMPA)
Connect the stabilizer to the polymer (grafting / copolymerization )
1. time antioxidant used in copolymerization with olefin under Ziegler-type conditions
M. L. Binet, S. Commereuc, P. Lajoie, J. Lacosta, J. Photochem. Photobiol. A: Chem., 137, 71, (2000)
T.L. Pattorn, J. T. Horeczy, D. E. Brown (to Esso Research and Engineering Co.) U. S. 3,477,991 (1969)
T. Iwata, J. Sasaki (to Mitsui Petrochemical Co., Ltd), Canadian 876,769 (1971)

6. Changes during processing
Manufacturer should guarantee not only the safe use of the additive but the product(s) of them after processing
There are some health concern in relation to BHT, the quinone form causes lung cancer in mice. Human health problem has not been proved yet.

7. Natural materials in packaging
Environmental and health problem due to synthetic stabilzers
Natural antioxidant: lignin, carotin, quercetin
Radical scavenger: vitamin E
carotin
vitamin E
quercetin
BIODEGRADABLE POLYMERS:
PHA, PHB, PLA
(Ecoflex, Ecovio)
Brocca, D.; Arvin, E, Mosbaek, H: Water Res., 36, , 2002
Pataki P., Imra B., Földes E., Pukánszky B., Műanyag és Gumi, 2012, 1

8. 1935/2004/EC regulation
This Regulation covers all materials and articles that are intended to come into contact with food: all types of packaging, bottles (plastic and glass), cutlery, and even adhesives and inks for printing labels.
They must under no circumstances transfer substances to the food with which they are in contact in quantities likely to:
endanger human health;
bring about an unacceptable change in the composition of the food; or
bring about a deterioration in the organoleptic characteristics thereof.
Active materials and articles: intended to come into contact with food: materials and articles 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 substances into or from the packaged food or the environment surrounding the food.
Intelligent materials and articles intended to come into contact with food: materials and articles which monitor the condition of packaged food or the environment surrounding the food.
2023/2006 EK GMT helyes gyártási gyakorlat

9. Active and intelligent material
Oxygen absorbents: ascorbic acid, metal-sulfides, glucose oxidase, catalase enzyme, amorphous polyamide
Oxygen exclusion: ethylene/vinyl alcohol closing coating
with Fe-compound
Water vapour absorbents: molecular sieve, silica, CaO, Al coating
Moisture controller: salts
Antimicrobial packaging: sorbic acid, Ag

10. Summary The use of plastics is rapidly expanding in food
packaging industry
The new products are more sophisticated and fit
better to the improved claims with special
polymers and active additives
These materials should improve not only the
physical, chemical but the health safety
properties of the package (EU) due to
- reducing migration
- and full controll of all the used
materials and evolved products during
processing

11. Macrostabilizer strategy
Compatibilizer
Hyperbranched polymer
Stabilizers

12. Acknowledgement HUSK /1101/1.2.1/0209 Hungarian Academy of Sciences
Research Centre for Natural Sciences
Institute of Materials and Environmental Chemistry
Department of Polymer Chemistry

13. Packaging
Barrier protection - A barrier from oxygen, water vapor, dust, etc., is often required. Permeation is a critical factor in design. Some packages contain desiccants or Oxygen absorbers to help extend shelf life. Modified atmospheres or controlled atmospheres are also maintained in some food packages. Keeping the contents clean, fresh, and safe for the intended shelf life is a primary function..
Convenience - Packages can have features which add convenience in distribution, handling, stacking, display, sale, opening, reclosing, use, and reuse.

14. Macromolecular stabilizers
Advantages
Very low migration to the surface
Long and predictable effect
Properties (eg. solubility, miscibility) can be easily modified by molecular weight and functionality
Disadvantages
Further functionalization reactions, which are often expensive and time consuming

15. INTERPACK 2011

16. Other additives
Antiaging additives:
BHT has been cleared by the FDA

18. MULTIFUNCTIONAL HYPERBRANCHED
POLYMERS
Dendrimers:
repetitively branched molecules start-up of one well defined central core
low viscosity
high chain-end funcionality
developing of generations can be made by only
expensive, difficult and time consuming methods
and reactions
Hyperbranced polymers:
no special main chain
statistical distribution of branch points
The branched polymers have all the beneficial properties of dendrimers.
Synthesis: different one-step reactions
Polycondenzation of ABn-type monomers
Sequential grafting
INIMER POLYMERIZATION
Self-grafting of polymers 18

19. ONE NEW CANDIDATE FOR BIO-FRIENDLY STABILIZER: HYPERBRANCHED POLYGLYCEROL
Properties
Synthesis: cationic or anionic Ring Opening Polymerization of glycidol
Well defined product (Mn, PD, number of OH-groups)
Good solubility in water
OH-groups can be functionalized easily
Biocompatible
does not induce an immune response
oligomers are FDA approved for food and pharmaceutical additives

20. THE TARGET STABILIZER

21. Effect of antioxidant Stabilization of chain-breaking antioxidants
Stabilization by preventive (secondary) antioxidants
phosphites, organic sulfides

22. Effect of heat stabilizer
The processing temperature is about °C.
ROOH + Mn ROO. + M(n-1)+ + H+
ROOH + M(n-1) RO. + Mn+ +OH-
2ROOH ROO. + RO. + H2O
Much more efficient inhibition is achieved by using metal deactivators, together with the antioxidants.
Mn+/M(n-1)+
Main function is to retard effectively metal-catalyzed oxidation of polymer.

23. Effect of light stabilizer
Small amounts of impurities or chromophores can be sufficient to induce photooxidaiove degradation even in the absence of appreciable UV absorption by a polymer.
Types:
UV absorbers: absorption of harmful UV radiation and it dissipation that does not form heat. Need a thickness. Hxdroperoxybenzophenones and hydroxyphenyl benzotriazoles.
Quenchers of excited states: light stabilizers able to take over energy absorbed by the chromophores present in the plastic and to dispose of it efficiently to prevent degradation.
Hydroperoxide decomposers: metal complexes of sulfur-containig compounds such as dialkyldithiocarbamates, dialkyldithiophosphates and thiobisphenolates.
Free radical scavengers: n-butylamine-nickel-2,’2-thio-bi-(4-tert.-octylphenolate) nickel-bis(3,5-di-tert.-butyl-4-hydroxybenzol-phosphonic acid monobutylester). Hindered amine typelight stabilizers: bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate.
Light stabilizer are chemical compounds capable of interfering with the physical and chemical processes of light-induced degradation. Most important classes: 2-hydroxybenzophenones, 2-hydroxyphenyl benzotriazoles, hindered amines and organic nickel compounds. Radiation between 295 and 400 nm initiates degradation.

24. Food packaging and use of stabilizers
Györgyi Szarka, Béla Iván
Department of Polymer Chemistry
Institute of Materials and Environmental Chemistry 
Research Centre for Natural Sciences, Hungarian Academy of Sciences