Compositional and Structural Changes of Corn Cob Pretreated by Electron Beam Irradiation

摘要

Effects of electron beam irradiation (EBI) on the content and structure of corn cob were evaluated in this study. Cellulose, hemicelluloses and lignin were separated and analyzed to investigate the structural changes in the pretreatment process. The results showed that EBI increased the removal of hemicellulose and lignin. Irradiation resulted in break and rearrangement between cellulose chains, the degree of polymerization (DP) of cellulose was reduced to the minimum (188) at 270 kGy, and part of cellulose was transformed from cellulose I to cellulose II. The thermal stability of the lignin extracted from pretreated corn cob decreased compared to that from raw sample. After the hydrolysis of the samples, the glucose yield and reducing sugar increased with the increasing irradiation dose and reached the maximum (44.3%) at 270 kGy after 48 h of enzymatic hydrolysis with an enzyme loading of 10 filter paper unit (FPU)/g of corn cob, which was 1.75 times of that of the untreated sample. The best yield of reducing sugar (267.9 mg/g corn cob) was obtained at 270 kGy after the hydrolysis with 2% sulfuric acid, which was 72.5% higher than the untreated sample.