Characterization of barrier properties and temperature resistance of biobased plastics for food packaging

With a steady annual growth rate of 8.7% from 1950 to 2012, finding a class of materials that is as successful as plastics will be very hard. Today, petroleum-based plastics, such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET) and polyamide (PA) are used in more and more applications and they have become an essential part of our modern lifestyle. Packaging, particularly food packaging, covers a big part of this plastics industry and trends like convenience and portioning have led to an increased use of raw materials, which is currently mainly crude oil. Environmental (consumer awareness, CO2-emissions) and economic reasons (dependence of oil industry) has triggered the interest of the food and packaging industry towards packaging materials made from renewable resources. Furthermore, increasing research and development in the field of these novel plastics leads to more and more applications and emerging new materials (Lagarón & Lopez-Rubio, 2011, OECD, 2013, Philp, 2014, Plastics Europe, 2013). Although the interest in biobased plastics is growing, a lot of stakeholders in the Flemish food industry are doubtful regarding the introduction of biobased plastics. This can mainly be attributed to the lack of knowledge regarding these new materials and their possibilities. Therefore, the aim of this research was to increase the knowledge of the different stakeholders within the food industry concerning biobased plastics by trying to close the gap between the academic world, where a lot of research in the field of biobased plastics is performed and the food/packaging industry to whom this research could be of great value

High barrier food packaging: convenience or necessity?: opportunity for bioplastics

The barrier properties (gas and moisture) of biobased food packaging materials are still an important issue regarding their introduction onto the market. In order to avoid unnecessary (expensive) testing, food companies make the decision to switch to a new (biobased) film mainly based on the oxygen (OTR) and water vapor transmission rate (WVTR) of their current conventional film, which is performing fine. For food products with a need for high barrier packaging material, this mostly means that biobased materials are not an option (or only at very high cost). But are these high barriers necessary to maintain the quality of the product? Storage tests with biobased packaging materials (mainly cellulose- and PLA-based), performed at Ghent University, showed that several biobased materials had sufficient gas and moisture barrier to guarantee the shelf-life of short, medium and long shelf-life food products, even when materials with lower barrier properties were used. The food products were packed under air or under modified atmosphere in pouches or in trays with a topfilm. The microbial and chemical degradation of the food products was followed up both in the biobased and in the conventional packages

Application of biobased materials for packing short, medium and long shelf life food products

The possible application of several multilayered biobased materials for packing different food products, ranging from short to long shelf life products, was investigated. Several transparent and metalized cellulose based film, a cellulose/PLA based film, a xylan based film and PLA trays with a PLA based film, a PLA/cellulose based film and a PLA/paper based film as topfilm were examined. The investigated food products were tomatoes, steak, French fries, ham sausage, filet de saxe (a raw cured pork meat product) grated cheese, tortillachips, rice cakes, dry biscuits and potato flakes all packed under air or modified atmosphere (MAP). The food products were stored at refrigerated (4°C) or room temperature and analyzed at certain points during their shelf life. For the short shelf life products, microbiological analysis (total plate count, lactic acid bacteria and yeast and moulds), gas composition of the headspace, color, aw and pH were followed and those quality parameters were each time compared with their evolution in the conventionally packaged food products. For the medium shelf life products also hydrolytic and oxidative lipid rancidity were monitored. For the long shelf life products no microbiological analysis were performed. Furthermore, sensory characteristics of the different food products were evaluated. From the storage experiments it could be concluded that most investigated biobased materials are good functional substitutes for the conventional packaging materials currently used. For example, the oxygen and carbon dioxide concentrations followed the same trend as in the reference film and the concentrations remained below the maximum limit or above the minimal limit during the entire shelf life of the food products