Although all varieties of orange-fleshed sweet potatoes (OFSP) are nutritious, the orange type may be the best source for vitamin A (VA), according to the research published in Comprehensive Reviews in Food Science and Food Safety (CRFSFS).
Sweet potato flour
One way food companies could develop improved varieties of prolific, hardy, disease and drought-resistant OFSP foods is through sweet potato flour, said the study.
“Currently sweet potato flour is produced in small amounts. However, larger companies may find opportunities in breeding nutritious sweet potatoes that: a) thrive in a variety of growing conditions; b) are suitable for making sweet potato flour,” said Betty J. Burri from the Western Human Nutrition Center at the United States Department of Agriculture (USDA).
The scientist said that international programmes are currently using sweet potato flour in biscuit and bun manufacturer.
In terms of consumer preference, Burri found that although many sweet potato growing countries traditionally eat cream or white sweet potatoes, when consumers were asked to switch from white to orange sweet potatoes, researchers have found little resistance.
“Thus, the impact of consumer preference on the success of OFSP programs to prevent VA deficiency should be small, perhaps on the order of 5 per cent to l0 per cent,” said the report.
VA-forming carotenoid concentrations vary with sweet potato colour, Burri found.
“The more orange the colour the higher the carotenoid content,” she said.
OFSP is also cheaper to distribute on mass than other forms of VA such as meat, the scientist claims.
In countries where vitamin A deficiency is common it would help if the food industry could find ways to increase the production and consumption of OFSP, said Burri.
Method and results
To reach these findings, Burri evaluated OFSP carotenoid concentrations, bioaccessibility, and cooking and storage. She then used this to estimate the amount of OFSP required to meet the VA requirement to all of the 208.1m people most in danger of VA deficiency.
“Many common varieties of OFSP are excellent sources of VA. They are relatively simple to grow, durable, and are easy to prepare. Currently, just over half of the sweet potatoes grown are eaten by humans. Therefore, OFSP have considerable potential as a nutritious, sustainable source for VA,” said Burri.
VA deficiency is a serious health issue for much of the developing world. It is responsible for over 600,000 deaths per year, mostly in young children or pregnant women.
The study concluded that for 1 year’s supply, 2.1 to 11.7m metric tons, or 2 per cent to 12 per cent of current world sweet potato production would be required.
Source: Comprehensive Reviews in Food Science and Food Safety
Published online ahead of print: doi: 10.1111/j.1541-4337.2010.00146.x
Evaluating Sweet Potato as an Intervention Food to Prevent Vitamin A Deficiency
Author: Burri, B. J