2.1. Materials
Expanded rice bran were purchased from Fushi Rice Industry Ltd, Kiamusze, Heilongjiang Province, China. In order to prevent rancidity, the raw materials were stored in the refrigerator at -20 ℃. Celluclast 1.5L, Pectinex Ultra SP-L, Viscozyme L and Alcalase 2.4L were purchased from Novozymes Bagsvaerd (Denmark). Hemicellulase and the standard of tocopherols, tocotrienols, sterols and squalene were obtained from Sigma-Aldrich Co. (Steinheim, Germany). Fatty acid methyl esters (FAMEs) standards were obtained from the AccuStandard (New Haven, CT, USA). Additionally, all other chemicals were of analytical grade.