Joanna Cosgrove10.21.10
It may be a tasty and versatile food staple, but the common potato is not exactly renowned for its antioxidant content; however “electrifying” research conducted by Japanese scientists may rewrite the nutritional reputation of the potato, raising it from common carb to antioxidant super spud.
In research presented at a meeting of the American Chemical Society, researchers from the Obihiro University of Agriculture and Veterinary Medicine in Hokkaido, Japan, explained that two inexpensive methods—delivering an electric shock or a zap of high frequency sound waves—effectively increased the amount of antioxidants in potatoes by 50%.
The ultrasound treatment consisted of immersing whole potatoes in water and subjecting them to ultrasound for five or 10 minutes. For the electrical treatment, the scientists immersed potatoes in a salt solution for 10 seconds and subsequently treated the spuds with a small electrical charge for 10, 20, and 30 minutes. The study team then measured antioxidant activity and the phenolic content and concluded that the stresses increased the amount of these compounds. The five minutes of ultrasound, for instance, increased polyphenol levels by 1.2 times and other antioxidants by about 1.6 times.
“We found that treating the potatoes with ultrasound or electricity for five to 30 minutes increased the amounts of antioxidants—including phenols and chlorogenic acid—by as much as 50%,” commented Kazunori Hironaka, PhD, the lead researcher and an associate professor in the university’s department of food science. “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.”
Dr. Hironaka told Nutraceuticals World that he has been researching chemical and physical properties of potatoes for many years, paying special attention to how stresses like drought or bruising could stimulate the accumulation of beneficial phenolic compounds. “In general, wounding increases polyphenols,” he said.
The introduction of stress via electric shock and ultrasound arose out of intuition. “We found that there hasn’t been any research on the healthful effects of using mechanical processes to stress vegetables. So we decided on this study to evaluate the effect of ultrasound and electric treatments on polyphenols and other antioxidants in potatoes,” he said. “I think that these treatments are useful for enriching potato antioxidant activity with non-destructive and short-time benefits.”
Why potatoes? The answer is one of local resourcefulness. “My university is surrounded by potatoes,” Dr. Hironaka said. “And, I had been researching potato physiology (low-temperature sweetening) and utilization for many years, so I chose potatoes naturally.”
Dr. Hironaka postulated that the process could have widespread commercial application, due to consumer interest in functional foods that may have health benefits beyond those of traditional nutrition, which promote overall good health or reduce the risk of health conditions or specific diseases.
Though his experiment with potatoes was a first, Dr. Hironaka said it will not be the last. He said other fruits and vegetables show similar potential when it comes to having their antioxidants boosted with either electricity or high frequency sound waves. “Stress-sensitive fruits/vegetables seem to be effective, for instance, banana, peach, grape and apple,” he said.
Dr. Hironaka is currently in the process of formally writing the research for publication. He said it will be contributed to "Journal of Agriculture and Food Chemistry" or "Food Chemistry" by the end of this month.