Soft wheat studies yield key findings
January 24, 2012
by Jeff Gelski
A series of whole grain flour studies conducted by the Agricultural Research Service of the U.S. Department of Agriculture has provided some answers as to how much dietary fiber is in whole grain flour made from soft wheat, and has enabled researchers to forecast what varieties of soft wheat plants are best for whole grain flours.
The studies were executed over five years at A.R.S.’s Soft Wheat Quality Laboratory at Wooster, Ohio. The group responsible for the project included Clay Snelling, associate professor with Ohio State University’s Ohio Agricultural Research and Development Center in Wooster. He conducted the research with Mary Guttieri a research specialist, and Edward J. Souza, a former research leader and plant geneticist with the Soft Wheat Quality Laboratory.
The research team used a nationally represented sample of soft wheat whole grain flours to determine the dietary fiber levels in soft wheat, whole grain flour. For example, the team used soft wheat kernels from 13 different wheat-growing regions, according to the A.R.S. The team also studied five different kinds of commercial whole grain soft-wheat flours.
The team sought to account for as many factors as possible, so they compared flours from each of two commercial wheat varieties grown at each of two sites in Ohio during three consecutive years, according to the A.R.S.
The research team found soft wheat whole grain flours averaged 14.8 grams of dietary fiber in each 100 grams of flour. The A.R.S. said the findings may be used in revised editions of nutrition databases that food manufacturers consult when making nutrition labels found on packaged foods.
In addition to the findings regarding the fiber content of whole grain flours made from soft wheat, the team also found that some soft wheat varieties were better suited for use in whole grain flours.
“In soft wheat, it’s a little bit more difficult to make whole grain products, and so we were looking to see if there were genetic variations in soft wheats for whole grain products such that there might be some way to tailor some of the soft wheats that are better suited for whole grains,” Dr. Snelling said. “We seemed to find some varieties that were a little bit better than others, and we were able to build a model that would predict what series of parameters you might want to make a better whole grain product from soft wheat.”
The findings from the A.R.S. flour studies may help food manufacturers increase the proportion of flour from whole grain in relation to refined white flour food makers currently use. Americans currently under-consume dietary fiber. The 2010 Dietary Guidelines recommend 14 grams per 1,000 calories consumed, or 25 grams per day for women and 38 grams for men. Americans’ usual intake averages 15 grams per day.
“This study reveals that consumers might be receiving even more fiber from Kellogg products than previously thought,” said Nelson Almeida, Ph.D., vice-president of Global Chemistry, Nutrition and Regulatory Sciences, Kellogg Co. “This is important because less than 1 in 10 American adults and children get enough fiber in their diets, and most get about half the amount of fiber they need, as recommended by the Institute of Medicine.”
Consumption of whole grains has been associated with health benefits. For example, a review of 25 studies published in the British Medical Journal found a high intake of dietary fiber, especially from cereals and whole grains, was associated with a reduced risk of colorectal cancer. Putting more whole grain flours into the foods that consumers buy and enjoy, such as crackers and cookies, may be one way to get consumers eating more whole grains and dietary fiber.
“Studies like this help us continue to meet America’s fiber deficit,” Dr. Almeida said. “Consumers also need to understand that the amount of fiber in whole grain products can vary greatly. They should specifically look for grain or whole grain foods that provide at least 3 grams of fiber to help meet their daily requirements without increasing calories.”
Food manufacturers may also use the research to buy grains from a certain variety, Dr. Snelling said.
“It could lead to them looking at the grain that they have coming in and be able to tell fairly quickly if it might be suitable for a whole grain product,” he said. “It would at least allow them to know how to handle it, and whether they need to add other materials, other ingredients to the flour to try to overcome inherent weaknesses or whether they can use it as is.”
Whole grain flour comes with many benefits, but reaping those potential health impacts comes with challenges.
“Soft wheat is typically used for products like cookies and cakes and pies and sweet goods,” said Kirk O’Donnell, vice-president of education at AIB International, Manhattan, Kas. “The reason for it is a lighter texture and if it’s used in bread it won’t rise high enough. It won’t have enough ability to hold its shape. When you go to whole wheat, the problem gets even worse.”
Also, removing the bran and the germ from whole grain takes out some of the nutrients that come with those components. The outer, or bran layer, of a wheat kernel contains important vitamins such as selenium and B vitamins, for example, according to the A.R.S. The wheat seed, or germ, also provides B vitamins and healthful fats. The endosperm, which constitutes most of the inside of a wheat kernel, contains carbohydrates and protein.
“The biggest thing that you don’t get when you go from whole grain to white flour whether it’s hard or soft, you’re missing the fiber and you’re missing a lot of the fat soluble vitamins, such as A, D and E,” Mr. O’Donnell said. “Pretty much all the fat is in the wheat germ.”
However, once the bran is added back in to flour it increases the water retention capacity of the resulting flour.
“Usually for soft wheat we like to have a low water retention capacity in the flour,” Dr. Snelling said. “Adding the bran makes the product more nutritious, but it also makes it difficult to make the type of products normally made from soft wheat.”
White flour may be stored for longer periods than whole grain flour because it is more stable compared to whole grain flour.
Another important factor food makers must consider is consumer acceptance. Can food manufacturers make a whole grain product from soft wheat that consumers will accept?
“While (consumers) want whole grain products, the current products have a different taste or feel to them,” Dr. Snelling said.