Enhancing the health benefits of peanuts

MANILA, Philippines - There is a process that dramatically increases the amount of resveratrol and other antioxidants in peanuts, according to two researchers.

Jocelyn Masiglat-Sales of the National Food Authority’s Food Development Center and Anna Resurreccion of the University of Georgia’s Department of Food Science and Technology said this process involves slicing raw peanuts, exposing the slices to ultrasound (US) waves and then to ultraviolet light.

The “application of abiotic stresses in peanuts increased its bioactive potential which can provide health benefits to consumers and value-added products to food manufacturers,” the researchers said.

In an abstract of the study, published in the Transactions of the National Academy of Science and Technology’s July 2012 issue, Sales and Resurreccion said they wanted to find out how “abiotic stresses” such as wounding, exposure to ultraviolet light and ultrasound waves could  be used to “enhance the bioactive potential of peanuts.”

They said that in certain plants, abiotic stresses increased the levels of polyphenols, including resveratrol. These compounds have antioxidant properties and may prevent illnesses “associated with with oxidative stress such as cancer, cardiovascular and neurodegenerative diseases,” according to the researchers.

Peanuts, in particular, contain resveratrol in amounts next to red wine and grapes, they said.

The results of the study showed that slicing raw peanuts increased resveratrol 19-fold, from .02 microgram per gram in controls to .37 mcg/g in sliced peanuts.

UV exposure alone increased resveratrol in sliced peanuts by ninefold or 3.3 mcg/g, whereas US wave exposure of sliced peanuts increased resveratrol 17-fold to 6.35 mcg/g.

Exposing US-treated sliced peanuts to UV further increased the resveratrol in them to 7.1 mcg/g.

This indicates “that US exposure is more effective than UV in enhancing resveratrol synthesis,” the researchers said.

To test their results, exposing peanuts to US then chopping them achieved a lower resveratrol level of 2.88 mcg/g, while whole US-treated peanuts registered the lowest resveratrol level at .99 mcg/g. This shows “that moderate wounding of peanuts by slicing is necessary for enhanced resveratrol synthesis,” Sales and Resurreccion said.

They added that wounding, exposure to UV, US and combined US-UV also increased the levels of other compounds such as piceid, and coumaric, caffeic and ferulic acids.