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From Science & Research

From Science & Research BREAD4PLA Biodegradable packaging for the bakery industry - made from bakery waste By: Rosa Gonzalez Leyba Extrusion Department AIMPLAS (Plastics Technology Centre) Paterna/Valencia, Spain Developing a totally biodegradable new package, made of waste from the bakery industry. This has been the aim of BREAD4PLA, a European project since in 2011 (cf. bM 04/2012) and which finished in September 2014. “We searched for a biodegradable polymer, made from sliced bread crusts and sponge cake, that could be later used in the conservation of these products in order to end with a full cycle”, says Rosa González, main researcher of the project at AIMPLAS, Technological Institute of Plastics (based in Paterna/Valencia, Spain). That was the original idea of this project, which is funded by the European Union Program LIFE+, and in which researchers from the Centro Tecnológico de Cereales-CETECE (the Spanish Technological Centre for Cereals), the Leibniz Institute for Agricultural Engineering Potsdam-Bornim e.V. (ATB, Germany), the Biocomposites Centre of the Bangor University (United Kingdom) and the Instituto Tecnológico del Plástico-AIMPLAS (the Spanish Technological Centre for Plastics) have all been involved. With the collaboration of all of the above organisations, and with the support of Spanish industrial companies such as Panrico and Grupo Siro, lactic acid and polylactic acid (PLA) have been obtained by way of the enzymatic fermentation of sliced bread crusts and sponge cake provided by the bakery industry. The lactic acid has been polymerized into PLA to produce plastic packaging. The result is a new compostable PLA film with which various types of bags and packages have been produced to package several food products. The fermentation of waste bread allows the production of 0.35 kg lactic acid per kilogram of bread, which is same range as for other feedstocks. Regarding the production of PLA, yields at this small pilot plant have been around 50%. From the same lactic acid, the yield in industrial process will be at least 77% based on data from pilot trials. So, depending on the scale, one kilogram of bread can be converted to 0.175 and up to 0.25 kg of PLA. However, in both processes, lactic and PLA production, some points have been detected to be improved and the yield increased, being more feasible to make improvements on a large scale, mainly based on purification processes. 32 bioplastics MAGAZINE [05/14] Vol. 9

“We have validated the new PLA package for different bakery products by analyzing its lifespan, conservation and organoleptic quality. Although initially we observed that the lifespan is reduced with sliced bread and biscuits, unlike the ones which are on the market, the behaviour of home-made butter-cakes and pastries was regarded perfect”, explains Ana Garcinuño, who is responsible for R&D at CETECE. As is known for commercial PLA packages on the market, the PLA that has been developed is less permeable to oxygen and more permeable to water vapour compared with traditional polypropylene (PP) and polyethylene (PE) packaging, and so initially it could be inconvenient for biscuits and cakes since they become much too soft as they take in moisture. The opposite problem applies to sliced bread which becomes too hard as it loses humidity. However, the low permeability to oxygen retards mould formation. These barrier properties are in fact an advantage for pastries and homemade butter-cakes. In this case, the film produced has the same performance as traditional packages made from fossil fuel sources, such as PP, leading to the same product shelf-life, thus becoming a much more sustainable alternative compared with the current solution. Moreover, it has other advantages which make it more attractive, such as the reduction of rancidity of the packaged food with this material (rancidity is the property that determines the extent to which the product is oxidized/degraded by the formation of peroxides). In addition, compostable tests performed using the packages developed, according to specific standards (such as EN 13432) for plastic packaging, confirmed the biodegradability and compostability properties, meaning that the product will be able to manage well under industrial composting conditions. In this way waste from the bakery industry takes on a commercial value, since it has not been used so far, and biodegradable and environmentally friendly packages are obtained - and used once again in the same industry. The BREAD4PLA project has been a demonstrative project performed on a pilot plant scale. Industrialization would be the next step. It will be necessary to consider the logistic aspects, such as the collection of adequate quantities of bakery waste and its transportation to the lactic acid production plant. The project partners are now working on this step to make it possible. DRIVING A RESOURCE EFFICIENT EUROPE Register now! 2/3 December 2014 The Square Meeting Centre Brussels More information is available at: Phone: +49 (0)30 28 48 23 50 bioplastics MAGAZINE [05/14] Vol. 9 33

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