Rice Quarterly: Tapping the potential of rice

by Emily Wilson
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The full potential of rice has yet to be tapped — especially in regard to using its flour, starch, protein, bran, hull and oil. At the USDA Agricultural Research Service’s Food Processing and Sensory Quality Research Unit (FPSQ), in New Orleans, Louisiana, researchers led by Elaine Champagne are tasked with inventing, designing and demonstrating novel methods of processing rice and its components into new, value-added products.

Food technologist, Ranjit S. Kadan, for example, has set his sights on making french fries from the flour of broken and immature or thin rice kernels.

"When you mill rice, you have about 15% that are broken or immature," said Kadan. These sell for slightly less than whole rice, usually for making beer, flour, and pet food.

Scientists before Kadan first tried making french fries from rice flour in the 1970s. "One of the main problems was how to add more water to rice flour during processing without making it too soggy," Kadan said.

In 1999, he overcame the problem with a novel rice flour processing method. The USDA filed a patent on the method in August 2000.

The key to Kadan’s approach involves processing mixtures of flour from different rice varieties into a dough that can be extruded into a french fry shape, precooked in hot oil, and then stored in a freezer until use.

Just as important were Kadan’s studies into the effects of amylose and protein in short-, medium-, and long-grain rices. This enabled him to refine the properties of rice fries so they more closely mimic those of potato fries.

Depending on the flour mixture, the rice fries in tests absorbed 25 to 50 percent less fat from oil during cooking than potato fries, Kadan said.

Kadan envisions rice fries that can be easily fortified with vitamins, minerals, soy or rice protein concentrate, and other nutrients.

The fries would also benefit from other desirable rice characteristics, such as excellent storage, easy digestibility, mild flavor, in addition to being hypoallergenic. Along with Rischellco, Inc., of Crowley, Louisiana, Kadan is consulting rice-processing experts on ways to commercialize the rice fries. .In other work, Kadan has begun experimenting with whole-rice bread for individuals with Celiac’s disease, an intolerance to wheat. Kadan said a rice bread mix would be particularly suitable for bread-machines.

A rice beverage is the next product Kadan has in mind. "By extruding rice flour, we can enhance its performance so that it will mix better with water and stay suspended longer," Kadan explained. His idea is to create a rice drink powder to which the consumer can just add water.


Meanwhile, ARS researcher Harmeet Guraya is seeking a commercial partner to help scale up a mechanized process he devised for cutting the cooking times of raw wild and brown rices, which usually haven’t been precooked and are packaged with their bran intact.

"These grains, as well as edible seed crops such as beans, require long cooking times largely because of their slow rate of hydration," Guraya said.

In general, these rices take up to 50 minutes of cooking to become soft enough to eat. This is mainly because waxy layers in the bran keep water from penetrating the grain.

Instant rice products cook faster because they are first soaked in water while raw, then cooked or steamed before a final drying step — a costly process.

"Many people are used to eating instant rice brands, but others prefer their rice fresh," Guraya said.

So about a year ago, he struck on the idea of "sandblasting" the rice grains — using rice flour instead of sand and a conveyor-belt-like setup for transporting the grain.

"The flourblasting technique is very simple, but it works quite well," Guraya said. Using 60 to 70 pounds of air pressure per square inch, the blaster riddles the rice with tiny, water-absorbing holes so that it cooks 66% faster than it normally would.

"The holes, nicks, and cuts formed on the bran aren’t visible to the naked eye and therefore maintain the aesthetic value of the original product," Guraya said. "The same concept could also be used with other edible seed crops with long cooking times, such as corn, wheat, oats and beans."

In addition to improving rice’s consumer appeal, Guraya is seeking to exploit the starch and protein found in the grain’s bran. Currently, sodium hydroxide is used to break down starch and protein particles and extract them from the bran. But the process is costly and can generate salt and other undesirable byproducts. Sodium hydroxide can also change rice protein’s nutritional properties, Guraya said.

As an alternative, he developed a process using high-pressure homogenization that breaks down the starch-protein agglomerates and separates them without changing their nutritional properties.

A cooperative research and development partner, Sage Five Foods of Los Angeles, California, U.S., has applied for a license on the technique.

There are myriad uses for rice protein and starch. They include pasta, baby foods, sauce thickeners and sprays for ironing clothes.

"America imports most of its rice starch from Belgium," Guraya said. "But if this technology pans out, it could cut down on such imports and make better use of our domestic rice crop. And that makes economic sense."