In an article published on October 30, 2021, in the peer-reviewed journal Analytical and Bioanalytical Chemistry, Jazmín Osorio and co-authors from the University of Zaragoza, Spain, and Queens University Belfast, Northern Ireland, UK, compared different analytical techniques to analyze oligomer migration from biopolymers into food simulants.
The scientists used food contact cups and dishes made of polylactic acid (PLA) and starch – two polymers based on renewable resources – and performed migration experiments following the EU regulation for food contact materials (FCMs). To determine the oligomers that migrated into the three food simulants, they used three different methodologies.
Osorio and co-authors detected several polyester oligomers in the migrates of PLA- and starch-based products, indicating that biopolymers “are commonly blended with polyester resins to improve their mechanical properties so they could not be considered as pure biopolymers.” They also reported that the two applied ambient desorption/ionization (ADI) techniques “are a very promising alternative tool to assess the safety and legal compliance of food packaging materials.” While ADI is commonly used to directly and rapidly analyze whether a target compound is present in a liquid or solid sample, the researchers find the two tested ADI techniques are also a powerful tool for the quick and simultaneous detection of polyester oligomers. A previous study reviewed chemical analytical approaches to detect food contaminants originating from packaging including biopolymers, and it concluded that different analytical techniques are required for a comprehensive analysis of migration samples (FPF reported).
In a book chapter published on October 19, 2021, by Teresa Cecchi and Carla de Carolis from the ITT Montani, Fermo, and the University Polytechnic of Marche, Ancona, Italy, discuss the current scientific literature on the safety of bio-based products. In contrast to the research study by Osario et al. focusing on oligomers, the book chapter focuses on catalysts used for the synthesis of bio-based products, the emission of volatile organic compounds (VOCs) from bio-based products in general, and the migration of additives from bio-based FCMs in particular.
Concerning catalysts, Cecci and Carolis give the example that tin(II)octanoate (CAS 4288-15-7) is commonly used in the polymerization of polylactic acid (PLA) as a ring-opener, which cannot completely be removed from the final product and has been shown to be genotoxic and cytotoxic. They further lay out that besides iron and zinc also other elements such as geranium can mimic tin catalytic activity. Cecci and Carolis emphasize that “nontoxic, highly active green catalysts for its [PLA] polymerization would be highly desirable” and although “the literature is still scarce … it is felt that the quantum leap from conceptualization of this idea to showcase the potential of this technology is not far.” Regarding VOCs, the authors report that scientific literature on VOC emissions from bioplastics is still largely absent and should be addressed by further research since VOCs’ “indoor presence was correlated to negative effects on human health and wellbeing.” As summarized in the book chapter, studies on bio-based plastics have so far only analyzed VOC emissions from PLA and its composites.
The chapter further explains that bioplastics, just as conventional plastics, need additives (e.g., plasticizers) and may even need the addition of more chemicals since they “are usually less stable and have a lower diffusion barrier than conventional plastics.” These chemicals may migrate from the packaging into the food (FPF reported and here). Also here, the authors call for further testing, for instance, to allow comparing migration behavior of chemicals from bio- and fossil-based products and “to perform an adequate risk assessment of nanomaterials used in bio-nanocomposites.”
Several reviews have previously examined bio-based polymers and also elaborated on the meaning of and differences among the terms “bio-based”, “biodegradable”, and “compostable” (FPF reported).
References
Osorio, J. (2021). “Comparison of LC-ESI, DART, and ASAP for the analysis of oligomers migration from biopolymer food packaging materials in food (simulants).” Analytical and Bioanalytical Chemistry. DOI: 10.1007/s00216-021-03755-0
Cecchi T., de Carolis C. (2021). “Assessment of the Safety of BioBased Products.” Chapter in: Biobased Products from Food Sector Waste. Springer, Cham. DOI: 10.1007/978-3-030-63436-0_10
