Product Development-Rice Bran 90

Product Development-90
Researchers seek method of increasing unsatu-
rated fatty acids in milk with modified rice bran

Project Leader and Principal UC Investigators

Edward J. DePeters, Dept. of Animal Science, UC Davis

Thomas Richardson, Dept. of Food Science and Technology, UC Davis

Researchers began exploring ways to develop a fat-protected rice bran product for the dairy industry to increase the proportion of mono-unsaturated and polyunsaturated fatty acids in milk. The goal is a new rice bran product that will enhance the nutritional characteristics of milk intended for human consumption.

"Initial attempts to develop a process that protects the unsaturated oil in rice bran have not succeeded."

To accomplish that objective, the researchers are attempting to develop a complex protein-sugar structure from unstabilized rice bran to protect the fatty acids in rice bran from biochemical changes in the cow's digestive system. The idea is that this will provide more unsaturated fatty acids for absorption by the dairy cow and increase the unsaturated fatty acid content of milk fat.

"Browned rice bran fed to dairy cows did not change the proportion of unsaturated fatty acids in milk fat."

After two initial studies, the researchers have not been able to successfully protect the fat in rice bran from those changes. In the first experiment rice bran was mixed with milk sugar and urea and then baked until browning occurred, a process requiring about four days. The treated rice bran was then fed to lactating dairy cows. There were no increases in the mono-unsaturated and polyunsaturated fatty acids following the feeding of the browned rice bran. That indicated that the initial attempt to protect the rice bran had failed.

In a second study, rice bran was mixed with a whey protein concentrate to ensure adequate protein was available for complexing with sugars in case the protein of rice bran was insufficient. The complex was then browned and fed to dairy cattle, as in the first experiment, but again, there was no change in either the gross composition or in the fatty acid composition of the milk fat.

"Future efforts will focus on use of extrusion technology to enhance the browning reaction in bran."

A third study is under way in which a food extruder is used to enhance the browning process. The extruder uses heat arid pressure to alter texture and improve nutrient availability. The extruded rice bran will be fed to lactating dairy cows and the milk subsequently analyzed.