Rice Utilization and
Project Leader and Principal UC Investigators
Robin M. Saunders,Western Regional Research Center, USDA, Albany, CA
The objective of studies at the USDA Western Regional Research Center is to
develop new products from rice for both domestic and foreign markets.
Products researched during 1982 were rice flours, rice germ as a potential
food, high-protein rice flour, liquid sugar from rice, and stabilized rice
bran and edible oil recoverable from this bran.
California medium-grain brokens were reduced to flour by grinding on several different mills. Flour particle sizes and functional properties were affected by the type of grinder used. Six rice flours of differing particle size were tested for water absorption capacity, amylograph viscosity, and other characteristics important to users of rice flour. The conclusions reached were that rice flour could be produced by various milling procedures to meet a variety of end-product uses. This information is being published and made available to potential users and could enlarge the markets for California-grown rice.
Current rice milling practices dispose of the germ along with the bran. The germ is high in essential lipids, quality protein, certain vitamins, minerals, and carbohydrates. This milling practice precludes the use of the germ as human food. Rice germ could become an attractive, stable, nutritious food. Sensory panels have reacted favorably to the odor of rice germ, as well as to the taste of bread, cake, and granola containing rice germ. The analytical data and storage properties for rice germ compare favorably with wheat germ, a relatively high-priced food ingredient. Riviana Foods is making rice germ on a pilot scale.
Research has continued on converting rice brokens to two new products - a high-protein rice flour and a rice sugar syrup. Mead-Johnson Company has followed this development closely and has contracted Anheuser-Busch to manufacture these products. Preliminary trials on incorporating the sugar syrup into baked goods have been successful. The high-protein flour excels as a potential infant food and as a snack ingredient.
The center has developed a small decorticating mill to test very small samples of short- and medium-grain California rices. In collaboration with Biggs, the mill is being modified so the test results on these samples are comparable with commercial milling.
Optimum conditions for stabilizing rice bran in a Brady extrusion cooker were found to be 130°C extrusion temperature at 13 percent moisture, holding at about 98°C for 3 minutes, then cooling in ambient air. Storage tests at 32°C and 85 percent RH for 28 days increased FFA by 1 percent compared to 48 percent in the unstabilized bran. Stabilized bran showed low microbiological counts, which did not increase during storage. Conditions were determined for dewaxing, bleaching, and deodorizing the oil recovered by hexane extraction from the bran. A thorough economic analysis of the process has been published by USDA. The bran stabilization system is presently installed at a California rice mill. Stabilized bran is undergoing tests as a food ingredient and as a feed in trials with chicks and pigs.
The center continues to conduct other federally funded research of direct value to the California rice industry.