Polymer-coated cardboards as strawberry packaging alternatives: The importance of considering close-to-real testing conditions in a food requirement-driven approach

Currently, packaging solutions are often chosen using a trial-and-error approach, by testing different materials that may be suitable for the product, often based on performance values measured under standard environmental conditions and on flat materials, sometimes differing from the performance in real conditions, e.g. fluctuating temperature, and after packaging converting. This can lead to sub-optimal solutions regarding food protection, with unnecessary costs and environmental impact. The purpose of this study was to show the efficiency of a food requirement-driven approach to select appropriate packaging, illustrated on strawberries packed in coated cardboard packaging, and the importance of considering the environmental conditions and converting steps. Therefore, optimal packaging O₂, CO₂ and water vapor transmission rates were calculated for strawberries. These optimal specifications allowed to select suitable tray material structures among polyvinyl alcohol-coated cardboards and a commercial cellulosic material for the lid, based on properties of flat materials under standard measurement conditions (50 % relative humidity (RH) and 23 °C). Then, flat materials were characterized under close to real environmental conditions (higher RH and different temperatures), and after converting (creasing, folding and sealing). Simulations of the packaging internal gas composition and of strawberries' water loss over time when packed in these materials were performed. Results showed no more modified atmosphere when considering the packaging performance at 5 °C and 100 % RH or after converting. Furthermore, increased water losses were predicted when considering packaging performance under high RH. This highlights the uppermost importance of considering real storage conditions and converting steps in the food requirement-driven packaging design.