Structural changes and enzymatic hydrolysis yield of rice bran fiber under electron beam irradiation

The enzymatic hydrolysis yield of rice bran fiber (RBF) was enhanced by the electron beam irradiation (EBI) pretreatment. Furthermore, the compositional analysis, structural changes and the thermal stability of RBF and its lignocellulosic fractions (cellulose, hemicellulose and lignin) were investigated in this study. The content of cellulose was significantly ( P   <   0.05) increased as the irradiation dose increased, ranging from 42.13% (0   kGy) to 52.31% (300   kGy). Conversely, the content of hemicellulose was decreased under the EBI pretreatment. The infrared spectra showed the breakage of the crystalline region of cellulose and the broken linkage between the lignin and hemicellulose. Additionally, the thermogravimetric analysis (TGA) proved that the thermal stability of the irradiated cellulose, lignin and hemicellulose was decreased when compared to the untreated samples. Particularly, the glucose yield of RBF achieved 34.99% at the irradiation dose of 250   kGy. The EBI treatment is a promising technology to improve the enzymatic hydrolysis yield of RBF, making it potential to become an alternative material for bioenergy.