Cereal Chem 69:152-156   |  VIEW ARTICLE

Stabilizing Brown Rice to Lipolytic Hydrolysis by Ethanol Vapors.

E. T. Champagne and R. J. Hron, Sr.. Copyright 1992 by the American Association of Cereal Chemists, Inc. 

Brown rice can be stablilized to lipolytic hydrolysis by exposure to vapors from boiling aqueous ethanol (EtOH). During six months of storage at 36 C, free fatty acids increased little or none in brown rice kernels treated with EtOH vapors for 3-10 min. Flours produced from treated kernels had low residual lipase activity. Treated kernels and flours prepared from them were more susceptible to oxidative deterioration than untreated kernels and flours, as indicated by increases in conjungated diene hydroperoxide content during storage. EtOH vapor treatment lowered the moisture content of the 12.8%-moisture brown rice kernels approximately 1.5%; loss of kernel oil was less than 3%. The water content of 8%-moisture kernels was not changed, and no oil was extracted by the EtOH vapor treatment. Thiamin and tocopherols were not lost in EtOH vapor-treated kernels. Thermal curves of treated and untreated kernels obtained by differential scanning calorimetry indicated no starch gelatinization in the treated kernels. EtOH vapor treatment of brown rice kernels reduced microbial populations to very low levels.