A hidden element in used coffee grounds could give them a use beyond plant food.
A new study in the Journal of Agricultural and Food Chemistry shows that antioxidants are abundant in the leftover coffee stuff we throw away. And perhaps we shouldn't be so surprised, considering coffee itself is known to be high in the compounds that help to beat the harmful effects of cell-damaging free radicals.
Researchers from the University of Navarra in Spain and the Technische Universität Berlin in Germany examined different kinds of coffeemakers to see which grounds had the most antioxidants left in them. They found that grounds left over in espresso-type, filter and plunger-type coffeemakers had the most antioxidants, while grounds left over in coffeemakers that make mocha drinks had the least antioxidants.
The findings suggest used coffee grounds could get a second life (aside from fertilizer) for use in supplements, researchers noted.