Fragments of fried dough, vegetable trimmings, and the juice left over from canned tomatoes: these byproducts of industrial food production can find new life in a range of commercial downstream products including biogas, bioplastics, or to make useful chemicals for industry, finds new research.
It’s the first study to highlight the potential value of industrial food waste and offer guidance to food manufacturers on how to financially capitalize on this resource.
The team behind the new Science of the Total Environment study saw food waste as a clear missed economic opportunity. To explore the potential uses of industry food waste, they surveyed 42 waste products, gathered from 11 food processing facilities in the US state of Ohio. Their sample set featured everything from tomato skins to cheese rinds, rogue soybeans, popcorn, spice dust, tea leaves, and the murky leftover water in vegetable tins.
For each of these the researchers analyzed its fat, starch, mineral, carbon and nitrogen profiles. These traits helped match particular waste streams with specific uses.
For example, they found that wasted soybeans and soybean oil have high energy concentrations that make them ideal as feedstocks for biodiesel production. High starch ingredients like breads and vegetable trimmings—especially uncooked potato pieces and skins—are a useful substrate for fermentation plants to make alcohols, and also acetone, a sought-after chemical solvent widely used in industry and scientific research. The same was true for wasted doughnut mix, which contains a 60% starch content, an untapped feedstock for bacterial fermentation.
Starch-heavy foods such as popcorn and inedible pizza can also be used to make bioplastics, the researchers showed. Meanwhile, products like sauerkraut juice and spice waste also contain a potent concoction of lactic acids, minerals, sugars, and proteins that are ideal feedstocks for yeast fermentation to produce commercial enzymes. What’s more, high fiber wastes like tomato peels and eggshells are excellent fillers for the production of rubber products, such as tyres, according to Beenish Saba, author on the new paper, and post-doctoral fellow with the LEGACY (Leading Engineering as Agents of Change and Equity) program at Ohio State University.
Even industrial wastewater and sludge, containing traces of food from processing, has value: the high levels of carbon in these streams makes them suitable for the production of hydrochar, a dried, carbon-rich material that’s used as an adsorbent to clear pollutants from water, or added to soil to help lock in more carbon and water on farmland.
Based on their findings, the researchers have created a simple roster and flowchart that could help guide businesses on how best to use their industrial food waste—whether it’s eggshells or vegetable peels.
Putting this into practice would require new structures and technologies: businesses would need ways to gather, process, and store the waste. With the costs of transporting waste elsewhere, it might make more sense also to build structures like fermentation tanks or hydrochar ovens on site. The research team is in fact now working on developing lab-scale bioreactors to test the use industrial waste and repurpose it into platform chemicals for industry, Saba says. Scaling this all up across businesses would require investment and time.
But the study is a step in that direction, helping reframe food waste as an opportunity rather than a nuisance—something that could generate a profit, rather than simply being a resource sink. “The bioeconomy is becoming much more prevalent as a topic of conversation. In this case, don’t get rid of food waste—make some money from it,” the researchers write.
Cornish et. al. “Characterization and potential valorization of industrial food processing wastes.” Science of the Total Environment. 2023.
