Sustainable Packaging for the Circular Food Economy

The impacts of food waste on the U.S. economy are staggering, accounting for 21% of fresh water use, 19% of fertilizer use, 18% of cropland, and over 21% of landfill volume, all at an annual cost in excess of $200 billion. Despite the current focus on food waste and methods for source reduction and landfill diversion, very little is known about the associated problem of food packaging waste (FPW). Although FPW is a subset of the much broader food waste issue, it represents an important topic requiring immediate focus, for two reasons. First, there is very little known about how much FPW is generated across the food supply chain, and published studies on this topic are almost nonexistent. To develop a broad food waste management strategy that will result in landfill diversion on a large scale, FPW needs to also be addressed so that value-added alternatives can be developed. Secondly, FPW represents a significant technical challenge because it is part of a “system” comprised of a biodegradable, organic fraction (i.e., the food material itself) combined with packaging material that may be recyclable, but in many cases is non-biodegradable (e.g., plastic) and thus different valorization methods are needed. It is desirable to develop entirely new methods for food packaging that essentially eliminates waste by using these materials at the end of life as value-added inputs to other stages of the food supply chain, thus enabling circularity and avoiding the take→make→waste practice of the conventional linear economy.

In this research, we explore two approaches for developing food packaging that supports a circular food economy model. The first involves bioplastic packaging materials designed to have accelerated rates of anaerobic digestion exceeding those of commercially available materials, using methods including co-polymerization, blending, and mineral fillers. Preliminary experiments also suggest there can be strong interactions between certain bioplastic materials and food waste, and we hypothesize that the food waste type (e.g., pre-consumer, post-consumer, etc.) may also play a role in accelerating the anaerobic degradation of these new bioplastic materials. The second approach involves development of composite packaging containing biochar, carbonaceous material produced by the thermochemical conversion of organic matter, including food waste. Thermoformed containers were manufactured with 10, 20 and 30 wt.% biochar derived from waste coffee grounds in a mixture of thermoplastic starch (TPS) and polycaprolactone (PCL). The addition of biochar decreased the elongation at break, but did not significantly affect the modulus of elasticity or tensile strength. Preliminary experiments also indicate that adding 10 wt.% biochar increased the biodegradation of the material. These approaches have motivated other innovations that may improve the sustainability of plastic use across the food supply chain, such as development of new biochar-bioplastic composite mulching films that fully degrade at the end of the growing season, and are designed to return organic carbon to the soil.