In our pursuit of swapping conventional plastics out for compostable, eco-friendly materials, corn starch has emerged as one of the most popular ingredients for environmentally friendly packaging.
But is it actually eco-friendly?
Corn starch is made from corn (or maize) grain and is largely known as a cooking ingredient used for thickening sauces and soups or making corn syrup.
The environmental impact of corn starch is generally positive, but recycling/composting corn starch products and cultivating it have their own impact.
Is corn starch environmentally friendly?
Corn starch can be used as a carbon-neutral, biodegradable alternative to plastics.
Using the sugars in corn starch, it can be processed into polylactic acid (PLA), which is more environmentally friendly than traditional plastic. PLA has the same characteristics as petroleum-based plastics and can substitute toxic plastics as packaging, disposable tableware, medical equipment like sutures, dog waste bags, textiles, and more. It is certified as food-safe and approved by the FDA.
In the right conditions, PLA degrades into carbon dioxide and water within 90 days, requiring a composting facility with high heat and the right microbes. Because of this, PLA isn’t as environmentally friendly as most believe, as it can only be composted industrially, like many eco-friendly alternatives to single-use materials.
This is one of the biggest drawbacks of many sustainable materials as we wait for more infrastructure capable of fully degrading waste without topping up landfills. If corn starch plastic enters recycling centers alongside other recyclable plastic it can also contaminate the rest of the plastic, resulting in salvaged plastic no longer able to be used.
It’s also worth noting that polylactic acid makes compost more acidic, requiring more alkaline to offset it before it can be used for plants.
Scientific American identifies corn-based plastics as potentially “not … much better than the plain old plastic it’s designed to make obsolete”.
They advocate for reusable containers over PLA containers, though other corn-based products are still better than traditional plastics. Their main concerns are the use of genetically modified corn – as the largest producer of polylactic acid is NatureWorks, a subsidiary of the world’s largest provider of modified corn seeds – and the processing and recycling of PLA.
Using Germany as a case study, research into the environmental impact of maize cultivation in the European Union notes that maize cultivation has similar environmental impacts to other row crops such as sugar beets and potatoes.
The improvements needed to lessen environmental harm are considered “often more expensive”, and due to this aren’t “standard in practical farming”. Since the eighties, legislation and reduction measures have been developed in Germany, and there is much more knowledge available on environmentally friendly farming systems.
One of the most well-known uses of corn starch industrially is as a fuel source. Ethanol is best known as alcohol, as it is the active ingredient in alcoholic drinks and is also used as a disinfectant, antiseptic, and more.
An environmental assessment of cornstarch-based ethanol as an alternative to gasoline for vehicles found that corn starch ethanol fuel contributes less to global warming and smog. It isn’t the perfect renewable fuel source but it’s better than conventional gasoline.
What can you use corn starch for?
There are many uses for corn starch and it’s usually what most plant-based products use. It can be used for pens, mugs, bags, medical equipment, plates, packaging, and so much more.
Corn starch is often used for practical uses like dry shampoo, polishing silver, increasing grip, loosen knots, removing stains, and making paint. You can even create nail polish and deodorant with corn starch.
Corn starch straws are a good alternative to plastic straws, and also don’t get soggy in water like paper straws. While they don’t perform as well as wheat or straw straws (which are more compostable and eco-friendly), corn starch straws are a cheaper option if you don’t like reusable straws.
Sprinkling corn starch on the carpet can help absorb oils and odors, just make sure to vacuum it up around half an hour later.
In fact, sprinkling corn starch can also deal with pest problems. Flea and ant infestations can be dealt with in a far more eco-friendly way by setting down corn starch, which is difficult for them to digest.
To get rid of stains, especially blood stains, you can mix corn starch and water together to make a paste. Paint the paste onto the stain, let it dry, and then wash it with your regular laundry. This works for carpet stains as well.
If there’s any stain left over, repeat the process or try white vinegar. Waste Advantage magazine notes that corn starch is best for grease stains.
Other than its use in ethanol fuel, corn starch is also used for microbial fuel cells, another type of renewable energy.
During the pandemic, research into producing bio-energy from Nigerian corn starch wastewater proved “a promising alternative energy source for off-grid power”.
Corn starch has even been identified as a potential alternative to concrete, with a 2017 study into corn starch-based building material using it as a binder with sand and water.
The cement industry contributes a great deal of carbon dioxide. By replacing cement with corn starch to create concrete, this could lessen the environmental impact of traditional concrete.
How to store corn starch
If you want to use corn starch around the house, it’s vital to keep it stored in an airtight container.
Humidity and moisture will be absorbed by the corn starch, which will decrease its useability. Always store corn starch in a cool, dry place, and put the lid on properly.
As long as the corn starch stays dry, it will be fresh for use indefinitely.
You should also avoid storing corn starch anywhere hot or near flames. Corn starch is a fire hazard and can potentially be explosive if corn starch powder is in the air.
The same can be said for regular flour or any kind of powder or fine dust, so make sure you’re storing these away from any heat sources.