Bioplastics in Food Packaging

 


Bioplastics in Food Packaging
 
Plastics are a huge part of food packages. They are widely used because of their easily shaped nature, low cost, and other functional advantages like optical properties, thermo sealability, microwavability. The use of petroleum-sourced materials in plastics production can pose a danger to the ecosystem due to their increased carbon release to the atmosphere, their long-term non-degradation in nature, and their carcinogenic effects [1]. So, is a world without plastic possible? It is quite possible with the use of bioplastics.
 
Bioplastics are plastic materials that are either biobased, biodegradable, or feature both properties, and Figure 1. depicts their classification in terms of biobased and/or biodegradable bioplastics [1,2].




Figure 1. The coordinate system of bioplastics’ classification [2].

 

Biobased and biodegradability are entirely different features. Biobased refers to the materials or products derived from biomass, such as corn, sugarcane, or cellulose. On the other hand, biodegradable materials undergo a chemical process during which no artificial additives are needed. Microorganisms in the environment convert these materials into natural substances such as water, carbon dioxide, and compost. This process is highly dependent on the environmental conditions and the chemical composition of the material.
 
Polylactic acid (PLA), polyhydroxyalkanoate (PHA), and polyethylene furanoate (PEF) are some of the bioplastics that deserve more attention.
 
      Polylactic Acid (PLA): PLAs are synthetic aliphatic polyesters. They are produced by renewable resources like corn cob, sugarcane bagasse, potato starch, barley, pretreated wood, or rice hulls by bacterial fermentation. PLA is synthesized by polycondensation or ring-opening polymerization reactions. PLA is a great food packaging material because of its high molecular weight, water solubility resistance, good processability, easy to process by thermoforming, and biodegradability. Processed PLA products can be found in various forms, such as films, containers, and coatings for paper and paper boards. It can be further recycled by chemical conversion back to lactic acid and then re-polymerized. However, if PLA-based products aren’t processed under appropriate conditions, it exhibits some limitations for biodegradation. It becomes brittle and can biodegrade much easily at higher temperature conditions.[3,4].
 
      Polyhydroxyalkanoates (PHA): PHAs are a class of bacterial polyesters produced with bacterial fermentation of sugar and lipid components. The monomers that compose different PHAs depend on the bacterial species that took part in the fermentation process. They exhibit thermo-mechanical properties akin to synthetic polymers like polypropylene, making it an ideal material to use. They have excellent tensile strength, flavor and odor barrier properties, heat sealability, grease and oil resistance, temperature stability, and are easy to dye, which boosts their application in the food industry. PHAs are used to produce biodegradable packages like bottles, containers, sheets, films, laminates, fibers, and coatings [5,6].
 
      Polyethylene Furanoate (PEF): PEFs are 100% biobased polyesters produced by the fermentation of corn or wheat-based sugars, wood, corn stover, or bagasse waste. It is polymerized by using 2,5-furan dicarboxylic acid and monoethylene glycol. PEFs possess comparable properties of thermal resistance to that of the PETs (polyethylene terephthalate). Furthermore, they provide twice the amount of water vapor barrier properties that make it an excellent packaging material. The EFSA panel announced that “the substance furan-2,5-dicarboxylic acid does not raise a safety concern for the consumer when used as a monomer in the production of polyethylene furanoate (PEF) polymer and the migration of the substance itself does not exceed 5 mg/kg food.” [7].
 
 
With the increased use of bioplastics, the greenhouse gas emissions that are the most important factor of climate change can be reduced drastically. Also, the recyclability and biodegradability of bioplastics create a more sustainable economy that can decrease the amount of plastic waste [8].

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CONTENT: Gökçe MAVİOĞLU

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REFERENCES


  1. Reichert, C. L., Bugnicourt, E., Coltelli, M. B., Cinelli, P., Lazzeri, A., Canesi, I., Braca, F., Martínez, B. M., Alonso, R., Agostinis, L., Verstichel, S., Six, L., De Mets, S., Gómez, E. C., Ißbrücker, C., Geerinck, R., Nettleton, D. F., Campos, I., Sauter, E., Pieczyk, P., & Schmid, M. (2020). Bio-Based Packaging: Materials, Modifications, Industrial Applications and Sustainability. Polymers, 12, 1-35.
  2. European Bioplastics. (2018). What are bioplastics? Retrieved from https://www.european-bioplastics.org/bioplastics/
  3. Malathy, A.N., Santhosh, K.S., Nidoni, U. (2014). Recent trends of biodegradable polymer: biodegradable films for food packaging and application of nanotechnology in biodegradable food packaging. Current Trends in Technology and Sciences, 3, 73–79.
  4. Cabedo, L, Feijoo, J.L., Villanueva, M., Lagaron, J.M., Gimenez, E. (2006). Optimization of Biodegradable nanocomposites based on a PLA/PCL blends for food packaging applications. Macromolecular Symposia, 233, 191–197.
  5. Mangaraj, S., Yadav, A., Bal, L.M.,Dash, S. K., & Mahanti, N.K. (2017). Application of Biodegradable Polymers in Food Packaging Industry: A Comprehensive Review. Journal of Packaging Technology and Research, 3, 77-96.
  6. Leja, K., Lewandowicz, G. (2010). Polymer biodegradation and biodegradable polymers—a review. Polish Journal of Environmental Studies, 19(2), 255–266.
  7. European Food Safety Authority (EFSA). (2014). Scientific Opinion on the safety assessment of the substance, furan-2,5-dicarboxylic acid, CAS No 3238-40-2, for use in food contact materials. EFSA Journal, 12(10), 1-9.
  8. European Bioplastics. (n.d.). Environmental benefits of bioplastics. Retrieved from https://www.european-bioplastics.org/bioplastics/environment/