What do you do with the peels once you’re done preparing your produce? If you’re like us, you might be used to simply throwing leftover fruit and veggie peels — like those from lemons, avocados, and bananas — right in the trash. Besides using them for zest in recipes, there’s no real use for that bitter outter layer of our favorite produce items, right? Well, new research suggests that we shouldn’t be so quick to toss our peels, since certain ones can actually serve a helpful purpose: purifying our drinking water.
A recent study, published in the Journal of Chemical Education, was conducted by a Dickinson College chemistry professor, Cindy Samet, and a team of student researchers. The team analyzed the chemical effects that certain fruit and vegetable peels had when submerged in water, and found that fruit and vegetable peels can indeed be used to remove pollutants like dyes and heavy metals from drinking water — a promising and cost-effective way of purifying water naturally.
Samet and her team performed water purification experiments using the peels and seeds from more than a dozen foods, basing the experiment off findings concluded in a 2015 study conducted by Suresh Valiyaveettil, Samet’s coauthor and a professor at the National University of Singapore. The original study analyzed avocado, hami melon, and dragon fruit peels, and their ability to remove impurities from water. Valiyaveettil’s experiment proved that these fruits have the ability to remove several pollutants from water, and Samet wanted to continue the research with a wider variety of produce items.
To further the research, Samet looked at produce items like pumpkin, okra, lemon, and banana for her own study. She and her team found that the peels of these foods removed methylene blue, lead, and copper through the process of adsorption. In other words, these pollutants adhere to the surface of the fruit and vegetable peels, and are therefore removed from the water. Lemon peels were proven to remove 96 percent of lead ions from water, while lemon seeds removed 100 percent of lead ions from water. The peels sourced from okra also removed 100 percent of lead from water, and okra seeds removed 50 percent of lead. And what’s more, the process they used is incredibly easy — no lab necessary! In fact, you can do it right at home in just four easy steps.
- Boil the saved vegetable or fruit peels for half an hour and pat dry (boiling is for purification and cleaning of the peel). Leave peels to dry out for a few days, which will eliminate most or all of the peel’s taste.
- Grind the peels using a mortar and pestle, or other grounding method.
- Using a strainer, submerge the ground peels into water and let sit overnight. (You can also submerge the dried peels themselves into your water and simply remove when ready to drink, though this may not be as effective as using the ground peels.)
- Remove the strainer from the water.