OSU, Korean researchers advance effort to turn spent coffee grounds into food packaging
CORVALLIS, Ore. (KTVZ) – Oregon State University and South Korean researchers say they have made a key advance in turning spent coffee grounds into food packaging materials that can extend the shelf life of products.
An estimated 60 million tons of spent coffee grounds are generated worldwide annually. Most end up in landfills and release methane, a potent greenhouse gas. That has led researchers to study other uses for coffee grounds, such as incorporating them into biofuels, cosmetics, catalysts and composite materials, including concrete, and now food packaging materials.
Coffee grounds are challenging to work with because tightly bound lignin, a complex organic polymer in plants that makes them rigid, is difficult to break down, said Jooyeoun Jung, an assistant professor at Oregon State University.
Jung, graduate student Cecilia Hernandez-Hosaka, and other scientists from Oregon State and the Rural Development Administration in South Korea studied two pretreatment options, one using formic and acetic acid and the other using ethanol. They cooked the spent coffee grounds with the two treatment options at high temperatures.
They found that the ethanol pretreatment provided the best results, significantly lowering the unwanted impurities, producing cellulose-rich materials that are desirable for eco-friendly packaging materials.
Once the solvent-based pretreatment was complete, the researchers pulped the grounds and used a low concentration of peracetic acid, an eco-friendlier alternative to traditional pulping methods that use other chemicals.
The peracetic acid helps lighten the grounds and create a cellulose-rich concentrate that resembles paste or mashed potatoes. The paste can be diluted as needed and then dried for various packaging applications.
The researchers can incorporate bioactive ingredients, which are substances found in plants and foods that can have desirable biological properties, including antioxidant and antimicrobial effects, into the packaging materials.
“We’ve shown that it’s possible to turn spent coffee grounds into biodegradable packaging products, instead of throwing them out,” Jung said. “This could aid the coffee industry by turning a waste product into a value-added, eco-friendly product.”
Still, more research is needed, Jung said. Future efforts will focus on refining the mechanical processing of the cellulose material to enhance its ability to resist things such as light, moisture and oxygen.
Research will also seek to improve the antimicrobial and antioxidant properties of the packaging to extend food product shelf life. Ultimately, a large-scale facility will be required to process spent coffee grounds for commercial applications.
The researchers believe coffee grounds could be used to make different food packages, including sheets between sliced cheese, pads underneath fresh meat and pads in clamshell containers used to package strawberries.
The findings were recently published in the Journal of Food Science. Other co-authors were Yanyun Zhao of Oregon State and Bo-ram Park of the Rural Development Administration in South Korea
The Oregon State researchers have also previously studied turning other agricultural waste products, including from apples and grapes, into packaging materials. They are also currently working with hemp stalks.
