In an article published on October 13, 2023, in the journal Food Additives & Contaminants: Part A, Dan Li from the National Reference Laboratory for Food Contact Material, Guangdong, China, and co-authors studied the volatile organic compounds (VOCs) in paperboard with food contact.
The researchers obtained from Chinese companies seventeen samples of uncoated paperboard intended for use in drinking cups, straws, baking paper, or yogurt boxes. Using headspace/solid phase microextraction (HS-SPME), they extracted the chemicals contained in a 2 g sample exposed to 80°C for 30 min. Since the scientists targeted VOCs, and odorous VOCs specifically, they applied the samples to comprehensive two-dimensional gas chromatography coupled to quadrupole-time-of-flight-mass spectrometry (GCxGC-QTOF-MS). Next, they compared the mass spectra and linear retention indices with a commercially available mass spectral library (NIST 17 library) for compound identification. Furthermore, they employed 13 reference standards for semi-quantification (i.e., estimation of levels) of some potentially detected VOCs and determined the most important odor-causing VOCs in their samples by calculating odor activity values.
Li and co-authors tentatively identified 344 VOCs in the investigated samples including aldehydes, ketones, alcohols, ethers, esters, alkanes, and aromatic compounds. 2-ethylhexanol (CAS 104-76-7), followed by nonanal (CAS 124-19-6), hexanal (CAS 66-25-1), and octanal (CAS 124-13-0) were present at the highest levels. The scientists highlighted five substances “due to their potential adverse impact on the organoleptic qualities of packaged food items and their potential toxicity” which were 2-methylnaphthalene (CAS 91-57-6), 2-pentyl-furan (CAS 3777-69-3), furfural (CAS 98-01-1), 1-octen-3-one (CAS 4312-99-6), and 1-octen-3-ol (CAS 3391-86-4). Among the 366 VOCs, they identified 66 as key odor compounds which may lead to a “distinctive green or plant-like aroma”, not only of the packaging itself but also of the packaged food. They named 12 substances associated with biogenic sources as the strongest contributors to odor.
Concerning their methodological approach, the scientists emphasized that 2D chromatography allows for a significantly better separation of chromatographic peaks compared to traditional GC-MS.
Previous studies have demonstrated that chemicals migrate from paper and board packaging – sometimes in amounts exceeding migration from plastics (FPF reported). Even when a barrier layer is added to avoid direct contact with food and paper, chemicals may still migrate into the food including metals (FPF reported) and per- and polyfluoroalkyl substances (PFAS; FPF reported and here). According to EU regulations for food contact materials and articles (EU 1935/2004, Art. 3), “a deterioration in the organoleptic characteristics” of the food is prohibited.
Reference
Li, D. et al. (2023). “Analysis of volatile organic compounds and potential odor compounds in food contact paperboard using headspace two-dimensional GC- QTOF-MS.” Food Additives & Contaminants: Part A. DOI: 10.1080/19440049.2023.2259029
