Food packaging and use of stabilizers

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

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

3. Polymer additives TYPICAL STABILIZERS Primarystabilizers/ antioxidants: Hinderedphenols, aromaticamines Secondarystabilizers / peroxidedecomposers: Organicthioesters, phosphites and metal-thiocarbamates Chelatingagent/metal deactivator: Organicphosphites and hydrazides FUNCTIONAL • Plasticizer • Lubricant • Antistatic • Filler • Foaming / Crosslinking • Colorant • Flame retardant PROTECTING • Heat stabilizer • Light stabilizer • Antioxidant

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

5. Strategies to avoid migration 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) • 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 )

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 • Brocca, D.; Arvin, E, Mosbaek, H: Water Res., 36, 3675-3680, 2002 • Pataki P., Imra B., Földes E., Pukánszky B., Műanyag és Gumi, 2012, 1 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)

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.

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. Macrostabilizerstrategy 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

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 Mn+/M(n-1)+ The processing temperature is about 180-200 °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.

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.

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