Extraction of Valuable Compounds from Hydrothermally Reacted Rice Bran and Wheat Bran

Abstract

Both extraction of valuable compounds and production of biofuels from rice bran and wheat bran were discussed by hydrothermal reaction. Existence of cerebroside was confirmed in the mixed solvent (chloroform and methanol) soluble but hexane insoluble constituent purified by alkaline treatment (P-MSHI) after hydrothermal reaction of rice bran at 100 °C, however, it decomposed by the reaction above 160 °C. Compounds consisted of any one of behenic, lignoceric and cerotic acids exist in the P-MSHI constituents from rice bran on the ratio of 1.0:3.3:0.9. The separation procedure carried out for rice bran could be applied for wheat bran. However, a part of hydrogen distribution of the P-MSHI constituent from rice bran was different from that of wheat bran. The intracellular fatty acids in rice bran were extracted by the second hexane extraction due to recovery of complex lipid during extraction by the mixed solvent of chloroform and methanol because palmitic, stearic, and linoleic acids are confirmed in both the water insoluble but hexane insoluble, and the mixed solvent soluble and hexane soluble constituents. Since half of rice bran was the hexane insoluble and mixed solvent insoluble (HIMI) constituent after hydrothermal reaction at 100 °C, the following reactions of the HIMI constituent were carried out in order to obtain more saccharides. The HIMI constituent decomposed significantly to gaseous products not saccharides on the second hydrothermal reaction at 240 °C. New compounds by either the Maillard reaction between polysaccharides and protein or hydrolysis of saccharides were generated during acidolysis of the HIMI constituent.