Publication Date:
2007-03-01
Description:
The lipid and lignin compositions of woods from the eucalypt speciesEucalyptus globulus,E. nitens,E. maidenii,E. grandis, andE. dunniihave been characterized. The lipid composition was analyzed by GC and GC/MS using short- and medium-length high-temperature capillary columns, which allowed the detection of intact high-molecular-weight compounds. Similar lipid compositions were observed in all eucalypt woods, which were dominated by sitosterol, sitosterol esters and sitosteryl 3β-D-glucopyranoside. These substance classes are mainly responsible for pitch deposition during kraft pulping of eucalypt wood. However, some quantitative differences were found in the abundance of different lipid classes, with wood fromE. globuluscontaining the lowest amounts of these pitch-forming compounds. The lignins of all eucalypt woods were analyzedin situ(without previous isolation) by pyrolysis-GC/MS. A predominance of syringyl (S) over guaiacyl (G) lignin units was observed and the S/G ratio was in the range from 2.7 to 4.1.E. globuluswood had the highest S/G ratio, a finding that, together with its low lignin content, explains its easy delignification under kraft cooking conditions.
Print ISSN:
0018-3830
Electronic ISSN:
1437-434X
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Permalink
