Potatoes can be made healthier, simply by zapping them with ultrasound or electricity, say scientists who say they could one day become a new "superfood".
Researchers found that by simply giving spuds an electronic shock makes them more nutritious by generating more antioxidants, which have been shown to combat heart disease and cancer.
Scientists from Obihiro University, in Japan, believe the technique, which created enough stress to trick the vegetable into producing antioxidants, could one day turn spuds into one of nature's ''superfoods''.
''We knew from research done in the past that drought, bruising and other stresses could stimulate the accumulation of beneficial phenolic compounds in fresh produce," said Dr Kazunori Hironaka, who led the study.
''We found that there hasn't been much research on the healthful effects of using mechanical processes to stress vegetables.
"So we decided in this study to evaluate the effect of ultrasound and electric treatments on polyphenols and other antioxidants in potatoes.
Dr Hironaka, whose team presented their findings at the 240th national meeting of the American Chemical Society in Boston, Massachusetts on Sunday, added: "Antioxidants found in fruits and vegetables are considered to be of nutritional importance in the prevention of chronic diseases, such as cardiovascular disease, various cancers, diabetes and neurological diseases."
Experts say potatoes, the world's fifth most widely consumed plant food, are already a good source of antioxidants, including vitamin C and compounds called polyphenols.
The chemicals mop up destructive molecules and also influence growth and cell death. Plants create antioxidants to help them survive stressful events such as drought, and attacks by pests and infections.
When consumed in plant foods, they are believed to protect arteries, reduce the risk of diabetes and help prevent the DNA damage that leads to cancer.
In their study the team of scientists built a laboratory ''torture chamber'' where they could subject spuds to high frequency ultrasonic sound waves or mild electric shocks.
The treatment almost doubled the levels of some antioxidants in the potatoes.
For the ultrasound treatment, the researchers placed whole potatoes in water and subjected them to 600 watt blasts of high-frequency sound for five or 10 minutes.
Electrified spuds were immersed in a salt solution and given 15 volt shocks for 10, 20 and 30 minutes.
The scientists then measured antioxidant activity and polyphenol levels, comparing them with those of untreated potatoes.
Five minutes of ultrasound treatment was found to increase antioxidant activity 1.5 times, polyphenol content 1.2 times, and levels of other antioxidants 1.6 times.
A 10 minute electric shock boosted antioxidant activity 1.6 times, total polyphenols 1.2 times, and levels of a polyphenol called chlorogenic acid 1.7 times.