Keeping peanut skins in the mix boosts nutrition, researchers find

Food scientist Dr. Tim Sanders and doctoral student Chellani Hathorn show that adding small amounts of peanut skin to products like peanut butter and peanut paste increase the nutritional value and antioxidant capacity of the products while only subtly changing the taste.

In a study published in the October issue of the Journal of Food Science, Sanders and Hathorn added varying amounts of peanut skin – from 0.5 percent to 20 percent concentrations – to peanut pastes and butters, testing the products' antioxidant capacity and flavor along the way. The researchers found that at lighter concentrations of 5 percent or less, the antioxidant capacity increased when compared with skinless peanut products, and that tasters didn't seem to mind a greater "woody" flavor.

At concentrations of 10 percent or more, however, antioxidant capacities continued to increase, but the taste buds rebelled: Tasters reported more negative flavor attributes, like bitterness, when eating peanut products composed of 10 and 20 percent skin.

Peanut skins, the seed coat comprising about 3 percent of a peanut seed, don't get much respect in the food world. Formed as a result of peanut blanching and roasting, skins are normally removed before peanuts are processed into a jar of your favorite peanut butter. Yet these skins are high in phenolic compounds, meaning they have antioxidant properties. Studies on antioxidants suggest they may protect against oxidative stress, which has been implicated in a number of diseases and cancers in humans.

Does the peanut-eating public have the stomach to handle some skin in their Skippy? Sanders and Hathorn point to this study and say that keeping skin concentrations low – 5 percent or less – could increase the health benefit and maintain peanut product palatability.

Journal reference: Journal of Food Science

Provided by North Carolina State University