A Look into Creating Sustainable Packaging Materials
In the past several years, the food industry has been moving towards more sustainable packaging. Two of which we will focus on in this article are bio-based materials and antimicrobial packaging. We’ll get an overview of each one and what makes them popular candidates for food packaging. After this we will review a joint project in which a team at UW Stout was looking to develop new packaging material that would meet the new demands of the food industry for food packaging. We’ll discover what they found and why permeation testing of their barriers was such an important piece to their success.
1. Bio-based Packaging
Due to the increased concern for petroleum-based plastics, i.e., non-renewable and non-degradable, a lot of effort has been invested into developing bio-based and/or bio-degradable packaging materials. It is estimated the production capacity of bio-based polymers in the world will triple from 10.2 billion pounds in 2013 to 34 billion pounds in 2020, in which 46% will be for packaging.
2. Antimicrobial Packaging
Driven by consumers’ healthy life style awareness, demands for minimally processed, preservative-free, “fresh” foods are continuously increasing. As one of the solutions, antimicrobial agents incorporated into packaging materials are developed to prevent the growth of microorganisms on the food surface and extend the shelf life.
However, there are challenges to these new material developments. For the Bio-based Packaging, performance and/or properties are not competitive to petroleum-based plastics, (PE, PP, PET, PVC, etc.) yet. In addition, the cost of bio-based verses competitive materials is still relatively higher at this stage. For the Antimicrobial Packaging, challenges include unpredictable release of antimicrobial (AM) agents, either completely bound in the polymeric matrix or suddenly released into the aqueous system. Also, AM may dramatically decrease the mechanical properties of packaging material.
A Joint Project to Create Antimicrobial Packaging
Project Director, Professor Min DeGruson at University of Wisconsin-Stout and her team worked on an innovative new packaging material for cheese packaging. The objective is to inhibit mold growth on packaged cheese, thus prolonging product shelf life while reducing preservatives in the food. To do this they worked on developing a starch-based antimicrobial (AM) food packaging by incorporating antimicrobial nano-particle systems into starch-based polymeric matrix with enhanced mechanical and barrier properties along with antimicrobial activity.
The material has the following features:
Bio-based Polymer: Corn Starch from Grain Processing Corporation
Nanoparticles: Layered double hydroxides (LDH) modified with antimicrobial agents in the lab
Antimicrobial Agents: Sodium benzoate and Natamycin from DSM
Professor Degruson’s team worked from scratch to prepare several versions of the new material with different load of antimicrobial nanoparticles. The formed film samples were characterized with wide angle X-Ray diffraction, FTIR and TGA-MS. Data showed that AMs were successfully loaded onto LDH (data not shown here). Mechanical properties such as Tensile strength and elongation at break were tested (data not shown here).
Another important piece to this new material creation was to test its barrier properties to ensure it would hold up against oxygen and moisture and meet performance requirements.
The barrier properties were tested at AMETEK MOCON Test Lab in Minneapolis, MN. The tests performed included water vapor transmission rate (WVTR), oxygen transmission rate (OTR), and carbon dioxide transmission rate (CO2TR). The test conditions were at 23C, 55%RH.
Instruments for barrier testing listed below respectively:
Now it was time to get the results and from that data they were able to make the proper decision on what barrier would work best for their application.
The permeation test results were listed in the following table.
Conclusion for Barrier Properties
WVTR, OTR and CO2TR significantly decreased after addition of AMs or LDH-AMs.
LDH-AMs do not have further influence on barrier properties compared to only AMs.
The new barriers give the ability to reduce waste and prolong shelf life
The barriers give brand owners the ability to remove preservatives, and move towards a more sustainable and eco-friendly packaging
Note: The related content was presented at the 2018 21st IAPRI World Conference on Packaging hosted by Jinan University and Hunan University of Technology 19-22 June, Zhuhai, China. "Packaging: Driving a Sustainable Future". www.iapri.org/events.php
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