Stéphane Peyron

Oxygen quantification methods and application to the determination of oxygen diffusion and solubility coefficients in food

Oxygen solubility and diffusivity in food are two key parameters to understand and quantify the impact of oxygen on food oxidation. A limiting step to the acquisition of these data is the availability and feasibility of methodologies to quantify oxygen content in food and especially in solid foods, even though some recent and significant progress has been made in this field with the development of easy-to-handle techniques. This review aims at presenting and discussing the existing methods to quantify oxygen within food. Data of oxygen solubilities and diffusivities in food are presented and the values are discussed in the light of the extensive analysis of the methodology used and of the food characteristics.

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

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.

Effect of high-pressure/temperature (HP/T) treatments of in-package food on additive migration from conventional and bio-sourced materials

Migration was assessed during and after two high-pressure/temperature (HP/T) treatments intended for a pasteurization (800 MPa for 5 min, from 20 to 40°C) and a sterilization treatment (800 MPa for 5 min, from 90 to 115°C) and were compared with conventional pasteurization and sterilization, respectively. The specific migration of actual packaging additives used as antioxidants and ultraviolet light absorbers (Irganox 1076, Uvitex OB) was investigated in a number of food-packaging systems combining one synthetic common packaging (LLDPE) and a bio-sourced one (PLA) in contact with the four food-simulating liquids defined by European Commission regulations. After standard HP/T processing, migration kinetics was followed during the service life of the packaging material using Fourier transform infrared spectrometer (FTIR) spectroscopy. LLDPE withstood the high-pressure sterilization, whereas it melted during the conventional sterilization. No difference was observed on migration from LLDPE for both treatments. In the case of PLA, migration of Uvitex OB was very low or not detectable for all the cases studied.

Effect of nanoclay on the transfer properties of immanent additives in food packages

Polymer nanocomposites and specifically clay-based nanocomposites are emerging in the food packaging area and are promised to have a growing market. While the advantages of the nanoparticles on the gas barrier properties of the nanocomposites are already well-investigated and confirmed, the effect of these nanoparticles on the migration of other non-nano and potentially toxic components of the polymer packaging has still remained unclear. The present study addressed the effect of nanoclay on the migration of various additives from nanoclay/LLDPE nanocomposite packaging by determining the apparent diffusivity of these additives from the samples in contact with four different types of food simulants that distinctively exhibit hydrophilic and lipophilic characters. The results indicated that apart from the tortuosity effect that influence in a low extent the diffusivity of model migrants, the presence of nanoclays modifies the transport properties of materials as a result of their impact on other factors such as crystallinity and swelling capacity. PLS analysis on the influential geometrical and physical properties additionally revealed that the affinity between the food simulant and the polymer has the dominant effect on determining the order of apparent diffusivity as well as the effectiveness of barrier properties of nanoclays to reduce the diffusivity of additives through food packaging. Such statements suggest a benefit provided by nanoparticles incorporation in terms of the human exposure to plastic additives.

Lignocellulosic Fibres-Based Biocomposites Materials for Food Packaging

Current requests in the field of food packaging lead to the reasoned design of materials able to improve the global environmental balance of the food/packaging system by minimizing the negative environmental impact of the packaging material while improving its positive role in the food wastes and losses reduction that strongly impact our environment. This means to simultaneously control food degradation reactions while limiting undesirable migrations of additives from packaging towards in respect of our health and remaining economically competitive. The substitution of oil-based materials by ones issued from renewable and non-food resources (e.g. issued from bioconversion of agro-food wastes, for example) and furthermore, fully biodegradable in natural conditions is also a necessity and represents a significant breakthrough from the research in the field of food packaging. In this context, increasing attention is given to full-biocomposites, i.e. composite materials based on constituents all biosourced and biodegradable. Developing full-biocomposites for food packaging requires taken into account numerous factors, and this is even more important for complex biodegradable materials due to the gap in knowledge on their behaviour and potentialities in usage conditions. The objective of this chapter is to decipher the state of the art on full-biocomposites by considering the specific stakes relative to the food packaging application. After the first part of introduction, the second part will present the role of packaging to ensure food quality and safety and how it should be designed in such a way to reduce food waste and losses. The third part will present the window of mass transfer properties of full-biocomposites, which is the main functional property when considering the food packaging application. The fourth part will consider the economical competitiveness of full-biocomposites, the fifth part will treat the safety issues and the sixth of the different options of end of life and waste management.

Antimicrobial soy protein isolate-based films: physical characterisation, active agent retention and antifungal properties against Penicillium italicum

Summary Soy protein isolates (SPI) films were evaluated as carriers of citral and limonene, and their physical and antifungal properties were evaluated. The presence of antimicrobials in SPI films resulted in changes on colour without affecting the transparency. Films with citral added were more extensible; however, a reduction in tensile strength and elastic modulus was observed in films with limonene added. Aroma compounds addition in films induced a slight increase in water vapour properties in relation to discontinuity of network proteins evidenced by SEM. Besides, FTIR spectra evidenced a partial alteration of SPI secondary structure. Citral was less retained than limonene. The increase in limonene release with high relative humidity was explained by increase in protein chain mobility. SPI films enriched with limonene exhibited strong antifungal activity against the postharvest decay pathogen Penicillium italicum under storage conditions.