Properties of polyolefins and biomaterials for food packaging

Cilj ovog rada bio je odrediti propusnost na vodenu paru i plinove (O2 i CO2), te vrijednost globalne migracije različitih materijala za pakiranje hrane. Mjerenja su provedena na poliolefinima, tradicionalno korištenim materijalima za pakiranje hrane - polietilen niske gustoće (PE-LD) i linearni polietilen niske gustoće (PE-LLD), papiru te biorazgradivom materijalu – poli(mliječna kiselina) (PLA). Prema dobivenim rezultatima biomaterijali su očekivano pokazali znatno slabija barijerna svojstva od plastičnih materijala. Papir je najpropusniji materijal na vodenu paru i plinove (O2 i CO2), a slijede ga PLA, PE-LD i PE-LLD. Među uzorcima dvije vrste polietilena nisu uočene statistički značajne razlike u propusnosti na vodenu paru niti na plinove. Vrijednosti globalne migracije u dva simulanta hrane (3 %-tna octena kiselina i 10 %-tni etanol) ukazuju na mogućnost korištenja PE-LD, PE-LLD i PLA u direktnom kontaktu sa hidrofilnom hranom, dok su kod uzoraka papira zabilježene povišene vrijednosti koje prelaze zakonska ograničenja.The aim of this work was to determine water vapour and gas (O2 and CO2) permeability and the value of global migration for various food packaging materials. Measurements were done on polyolefins, materials traditionally used for food packaging – low density polyethylene (PE-LD) and linear low density polyethylene (PE-LLD), paper and biodegradable material – poly(lactic acid) (PLA). According to obtained results, as expected, biomaterials were shown to have significantly poorer barrier properties than plastic materials. Paper was the most permeable material to water vapour and gases (O2 and CO2), followed by PLA, PE-LD and PE-LLD. There were no statistically significant differences between two tested PE materials for water vapour or gas permeability. Global migration values on two tested food simulants (3 % acetic acid and 10 % ethanol) indicated the possibility of usage of PE-LD, PE-LLD and PLA in direct food contact with hydrophilic food, while paper samples demonstrated higher values that are above the overall migration limit given by legislation