Safety profile of ZnO active packaging PBAT based biomaterial for food packaging. First tier evaluation

Abstract

Materials produced with polybutylene adipate terephthalate (PBAT) and starch are raising great interest for packaging and food contact applications, including as support for active antimicrobial agents such as zinc oxide nanoparticles (ZnO). Studies focusing on the safety of these materials as evaluated with the current reference rules for food contact materials, are lacking. A commercially available PBAT/starch-based material was incorporated with ZnO and the overall and specific migration of the films were studied at different conditions of simulants and temperature. The overall migration (OM) limit is exceeded due to the release of starch as confirmed by infrared spectroscopy. The impact of temperature on the OM was higher for the ethanol 10%. The incorporation of ZnO particles reduced the OM, for both temperatures tested for ethanol 10%. The impact of incorporating ZnO in the migration into acetic acid was relevant at 20 °C only. Beside starch, most relevant migrants were PBAT oligomers made of butanediol and two different kinds of diacids, terephthalic acid or adipic acid. The cyclic diester of 1,4-butanediol and adipic acid, butenyl butanediol adipate in either cyclic and linear form and oligomers terephthalic acid, but-3-enyl hexadecyl ester were detected in an untargeted screening with GC-MS. A second TPA oligomer was not fully identified. The specific migration was in several cases, depending on the simulant and on the temperature, higher than 50 μgkg−1 (semi-quantification), the threshold value for requiring additional toxicity test (genotoxicity tests applied to oligomers below 1000 Da). This indicates the need for more detailed studies with more precise quantification to verify the need for toxicity tests.