Title
Extracting hemicelluloses from softwood and bagasse as oligosaccharides using pure water and microwave heating
Authors
TOREA A. GULBRANDSEN INGVILD A. JOHNSEN MIHAELA TANASE OPEDAL KAI TOVEN KARIN ØYAAS ANDREY PRANOVICH JYRI-PEKKA MIKKOLA and BARD H. HOFF

Received January 3, 2014
Published Volume 49 Issue 2 February
Keywords hemicelluloses, microwave hot water extraction, softwood, sugarcane bagasse

Abstract
The objective of the study was to identify conditions for hemicelluloses extraction in oligomeric form. Using microwave assisted hot water extraction (HWE), the effects of both retention time and temperature on hemicelluloses yields, as well as the degree of polymerization (DP) as analyzed by SEC-MALLS, were investigated using both softwood (sawmill shavings) and sugarcane bagasse. The results are discussed in the light of the unavoidable yield-DP compromise resulting from the application of batch mode operations. Nevertheless, significant differences between the two raw materials could be observed, as expected. For softwood shavings, data interpolation indicated that about 50% of the hemicelluloses could be obtained as oligomers at an average DP of 30 when extracted at 183 °C for 5 minutes. For bagasse, longer extraction times seemed optimal. After hot water extraction at 183 °C for 12 minutes, about 62% of the bagasse hemicelluloses were extracted as oligomers at an average DP of about 100.