Separation, Purification, and Drying of Starch and Protein Using a Novel Rice Wet-Milling Technique

Current methods of separation of starch and protein that have been successful in producing corn and other types of starches do not work well with rice. Rice granules are very small (usually about 3 to 6 microns in size) and are difficult to separate from rice protein, which are of similar size. Yields of starch are low, recovery of quality protein is rarely achievable, and so the resulting rice starch is too expensive to compete in the market. The unique small size of rice creates market opportunities for rice starch if cost could be reduced. We hope to commercialize a physical process to separate rice starch from rice protein. We hope to improve the yields of starch, produce a high quality rice protein that can be sold into the human market, and reduce costs of wastewater treatment. If successful, our process would use clean untreated water. The starch and protein produced from such a process would be "all natural" and potentially more valuable to the market than chemically treated starches. We will continue to work with and develop a concept that was initially developed by the USDA research lab in New Orleans through a CRADA with Sage V Foods, and then further developed in a phase 1 SBIR Grant. Under certain conditions a microfluidizer machine has been shown to physically separate starch and protein by causing the particles to collide against each other while in a liquid slurry at very high pressures. The overall objective is to develop a method of rice starch extraction that will make the manufacture and marketing of rice starch an economic success by increasing the yields of pure starch extracted from rice to over 70% (preferably over 75%) and to produce and recover a marketable protein that has not been treated with chemicals. The target yield for protein is greater than 6% at 80% purity. The specific objectives of the project will be: 1. Test various chamber and pressure conditions in the "microfluidizer" to determine the best shear conditions for protein that produces a functionality that facilitates separation of starch and protein. 2. Test two different types of nozzle disc centrifuges (Westfalia separator and Alpha Laval) in combination with additional centrifugation and/or hydrocyclones and various processing techniques to obtain starch purity of 99.5%, while at the same time achieving protein purity of over 80%. Also test a basket centrifuge and peeler centrifuge for the same purpose. 3. Utilizing centrifuges and hydrocyclones, develop an economical method to recover rice protein from the wash water and then dry the protein. Achieve yields of greater than 6% at 80 percent purity. 4. Test spray drying and basket centrifuge/oven drying to develop an economical method to dry rice starch, while producing a product of less than 10 micros size and without developing rancidity.