Application of FTIR and Raman microspectroscopy to the study of food/packaging interactions

Abstract

This study assesses the suitability of Fourier transform infrared spectrometer (FTIR) and Raman spectroscopy for potential use as analytical tools to determine the diffusivity of a migrant in a plastic packaging material, one of the key points in safety assessment of food-contact materials. Despite its relative low sensitivity, FTIR-based analysis supplied data for the material on desorption of an additive (Uvitex OB) and sorption of a food constituent (olive oil) in a non-destructive and ‘in situ’ mode. These data allowed the determination of the diffusivity of Uvitex OB (8.0 ± 2.5 · 10⁻¹⁴ m² s⁻¹) and olive oil (6.9 ± 3.4 · 10⁻¹⁴ m² s⁻¹) in Linear Low Density Polyethylene (LLDPE). Raman cartography innovatively supplied the profile of additive concentration in the z-direction (thickness) of the food-contact material and confirmed that mass transfer in the system roughly followed a Fickean behaviour.

Keywords:

• chemometrics
• method validation
• additives general
• packaging–migration modelling
• olive oil

Acknowledgements

This study was carried out with financial support from the Commission of the European Communities, Framework 6, Priority 5, ‘Food Quality and Safety’, Integrated Project Novel Q FP6-CT-2006-015710. The authors would like to acknowledge Professor Salvatore Iannace and co-workers from IMCB (Naples, Italy) for the preparation of the films used in this study.