Valérie Guillard

Oxygen and Carbon Dioxide Solubility and Diffusivity in Solid Food Matrices: A Review of Past and Current Knowledge

Oxygen and carbon dioxide solubility and diffusivity are 2 key parameters to understand gas transfer in food matrices. Knowledge of these parameters could help to predict gas concentration in modified atmosphere packaging and, consequently, to predict shelf-life of the product through the development of appropriate mathematical models. The aim of this review is to present the existing methodologies to quantify O2 and CO2 contents in food, especially in solid food matrices which is very challenging. There is a focus on how these methodologies could be used to determine gas transfers kinetics. Data of O2 /CO2 solubilities and diffusivities in food are collected and compared with a specific emphasis on the food characteristics and factors impacting them. An analysis of the current state of knowledge in solid food matrices is carried out to tentatively build a general predictive model of the O2 and CO2 solubility and diffusivity extendable to any kind of food matrix.

Changes in nutritional and sensory properties of orange juice packed in PET bottles: An experimental and modelling approach

Sensitivity to oxidation of an orange juice was investigated through packaging in standard PET or active PET with oxygen scavenger bottles. The evolution of dissolved oxygen was found to be similar in all bottles, whereas ascorbic acid degradation was related to the oxygen transfer with higher losses in standard PET (53%) against active PET (31%). Moreover, when juice was exposed to high intensity light, a fold faster degradation of ascorbic acid was observed compared to total darkness. Depending also on the light intensity and regardless of the package permeability, changes in the aromatic profile of the juice were observed due to the degradation of limonene and the formation of α-terpineol, an off-flavour. A mechanistic model was developed to predict the shelf life of orange juice. This model, coupling O2 transfer and ascorbic acid oxidation reaction in the bottled juice, confirmed that oxygen permeation through packaging material could not be neglected.

Choice of environment-friendly food packagings through argumentation systems and preferences

Food packaging plays a crucial part in the post-harvest environmental impact of fresh foods. Packaging is usually wrongly considered as additional economical and environmental costs. However, by minimizing food waste and losses, it could significantly contribute to decrease the overall environmental impact of the food itself. A good balance between environmental burden (resource consumption and additional waste management issues) and real benefit in usage condition (reduction of food losses) should be thus defined when dimensioning a packaging for a given application. Beyond food waste and environmental impact reduction, various kinds of considerations about packaging, sometimes conflicting, are generally expressed by the stakeholders (food and packaging industries, health authorities, consumers, waste management authority, etc.) related to safety, practicality, perceptions of the packaging material, etc. Therefore, to help the parties deciphering all these arguments, we designed an argumentation-based tool to take into account the conflicting preferences expressed. The requirements concerning packagings are modeled by several arguments provided by the stakeholders expressing their viewpoints and expertise. Based on a new attack relation, the argumentation tool computes sets of compatible arguments which are used to rank alternative packagings under debate. In this paper, we present a complete workflow implemented as a software prototype starting by defining a structured representation of experts arguments and poll results, and ending by a ranking of packaging solutions. We show and discuss the results obtained by the software on a use case study (fresh strawberries) to determine the justifiable choices between several packaging materials based on stakeholders arguments.

A global visual method for measuring the deterioration of strawberries in MAP

Graphical abstract

Relationship Between Multiscale Food Structure and Moisture Transfer Properties

The structure of the food materials has a major impact on the diffusion rate and, consequently, on the value of effective diffusivity or water vapor permeability. On the contrary, water sorption at equilibrium is less or not affected by the structure. Among structure type, porosity particularly affects the diffusion rate. In a porous domain, molecules are allowed to transfer more quickly because of several mechanisms of moisture transfer (e.g., capillary action), vapor diffusion in the pores, and so forth, along with liquid diffusion. In low-porosity materials, liquid diffusion is the main means of moisture transport. The smaller the pores’ size in the matrix of the food domain, the slower the moisture migration. In addition, membranes, crystals, and lipids all contribute as barriers to moisture migration. In such dense materials, elements of structure affecting the diffusion rate are in the nano- or microscale, whereas for porous materials, structural elements at the micro- and macroscales are more predominant.