By Lola Gayle

After grapes are juiced to make wine, what happens to the seeds, skins, stems and solid matter that are left behind after the grapes are crushed?

According to the website The Press Democrat, some are thrown away, but the byproduct known as pomace can sometimes find its way back into the food stream as compost, flour, cooking oil, distilled spirits or even ethanol.

All these options are wonderful, but researchers have found another interesting use for the waste product: add it to coffee to up the antioxidant level.

In a new study published in the Journal of Food Science, researchers from Washington State University also found that adding a small amount of Chardonnay grape seed pomace (GSP) to coffee did not significantly alter the appearance, taste or aroma of the hot beverage.

For the study, the researchers conducted two consumer panels to assess the acceptance of coffee with additions of GSP values of 0% (control), 6.25%, 12.50%, 18.75% or 25%. The first consumer panel assessed the coffee samples served “black.” The second panel assessed the coffee samples with sweeteners, milk and cream options available.

According to a statement from the Institute of Food Technologists, consumer sensory evaluation involved evaluating the five treatments individually for acceptance of appearance, aroma, taste/flavor, and overall acceptance using a 9-point hedonic scale. A check-all-that-apply questionnaire surveyed the sensory attributes describing aroma, appearance, and taste/flavor of the samples. Oxygen radical absorbance capacity was used to measure the effects of antioxidant levels in GSP coffee samples.

In the end, the researchers found that the optimal level of GSP in regards to overall consumer acceptance of coffee compared to the control was 6.25%. Anything above that and the coffee was described as more tan, milky, watery/dilute, and mild, and was generally less accepted by the consumers. GSP also increased the antioxidant capacity of the coffee compared to the control (0% GSP), with no significant differences among replacement values.

The researchers concluded that the results may be “useful in the development of a new coffee beverage, in addition to developing other avenues for use of grape seed pomace.” They noted that further investigation may substantiate the free-radical scavenging capacity of GSP coffee and its potential health benefits.

Read the Journal of Food Science abstract here.

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