And since the genetic modification was accomplished without inserting any foreign genetic material into the potato's genome, the researchers hope to calm any consumer concerns about the new spud variety.
Acrylamide is a carcinogen that is created when starchy foods are baked, roasted, fried or toasted. It first hit the headlines in 2002, when scientists at the Swedish Food Administration first reported unexpectedly high levels of acrylamide, found to cause cancer in laboratory rats, in carbohydrate-rich foods.
Since the Swedish discovery a global effort has been underway to amass data about this chemical. More than 200 research projects have been initiated around the world, and their findings co-ordinated by national governments, the EU and the United Nations.
Writing in the Journal of Agricultural and Food Chemistry, the Idaho-based researchers report that by reducing the expression simultaneously of the Ranger Russet's tuber-expressed polyphenol oxidase (Ppo), starch-associated R1, and phosphorylase-L (PhL) genes, achieved without introducing any foreign DNA.
"By committing to all-native DNA transformation methods for the incorporation of output rather than input traits, we hope to address at least some consumer concerns about the genetic modification of food crops," wrote lead author Caius Rommens in the Journal of Agricultural and Food Chemistry.
The researchers report that, by reducing the expression of these specific genes, when the potatoes were processed and fried to produce French fries, the fries contained about one-third the acrylamide content of control fries.
"Because consumption of French fries was recently estimated to contribute to about 16 per cent of the total dietary intake of acrylamide [in the US] (0.07 micrograms per kg of body weight/day), application of the "low acrylamide" fries would reduce the daily acrylamide intake by more than 10 per cent," they said.
Sensory evaluations, by a panel of eight professionally trained experts, also showed that, somewhat unexpectedly, the sensory attributes were enhanced in the 'intragenic' spuds.
"Our results demonstrate that a multigene silencing construct enhanced the performance of Ranger Russet in seven different ways: black spot bruise resistance, reduced cold-induced sweetening, reduced stress-induced sugar ends, enhanced fry aroma, reduced amounts of processing-induced acrylamide, reduced starch phosphate content, and increased starch," wrote the researchers.
"We have shown that both the sensory and nutritional characteristics of potato can be improved by simultaneously silencing the tuber-expressed Ppo, R1, and PhL genes," they said.
The news could see the Ranger Russet expand its current market penetration in French fry production, from its current level of about 20 per cent. The limited use has been put down to storage problems, including sensitivity to bruising and cold-induced sweetening.
Compared to more commonly used Russet Burbank, the Ranger Russet has superior yields and greater disease resistance.
"By replacing some of the acreage that is currently occupied by Russet Burbank, it will also be possible to increase yields and lower costs for disease control," said Rommens.
The news could also see Ranger Russet growing increased in Europe. The variety is said to have excellent adaptability.
Source: Journal of Agricultural and Food Chemistry Published on-line ahead of print; ASAP article, doi: 10.1021/jf062477l S0021-8561(06)02477-0 "Improving Potato Storage and Processing Characteristics through All-Native DNA Transformation"
Authors: C.M. Rommens, J. Ye, C. Richael, K. Swords