Fresh olives are very bitter in taste due to the presence of phenolic compounds such as oleuropein and ligstroside. Scientists have found eco-friendly alternatives using resins to soak up these bitter phenolic compounds from whole olives during typical brine storage. The findings of the study are published in ACS' Journal of Agricultural and Food Chemistry.
Olives are staples of the Mediterranean diet, which has been linked to a reduced incidence of cardiovascular disease, Alzheimer's disease, and other conditions. However, freshly picked olives are very bitter and require curing or processing to make them palatable, using lots of water and, sometimes, harsh chemicals. Now, researchers have found a more environmentally friendly way to remove bitter phenolic compounds from olives.
The bitter taste of phenolic compounds such as oleuropein and ligstroside may help protect olives from herbivores and pathogens. To make olives edible, commercial processors typically destroy these compounds by soaking the fruit in a dilute lye solution, followed by washing several times. However, this process consumes large amounts of water and produces toxic wastewater. Alyson Mitchell and Rebecca Johnson wanted to develop a more environmentally sustainable method to remove the phenolic compounds from olives.
Afterward, the researchers treated the resin with ethanol to recover the olive phenolics, which were still intact. They say that the recovered phenolics can be used later as high-value ingredients or supplements.