Chemical alterations of pine wood saccharides during heat sterilisation

Abstract

Alterations in saccharides during heat sterilisation of pine wood (Pinus sylvestris L.) were investigated. The mass loss, extractives, lignin, cellulose, holocellulose and hemicelluloses were determined. Changes in saccharides were evaluated by the determination of monosaccharides in wood, size exclusion chromatography (SEC) as well as Fourier transform infrared (FTIR) spectroscopy. During heat sterilisation of pine wood the slight mass loss, an increase in extractives and a decrease in lignin and polysaccharides were observed. Hemicelluloses are degraded approximately twice as fast as cellulose. The degree of polymerisation of cellulose decreases approximately by 10% and it increases in holocellulose (by approx. 8%) as a result of a faster degradation of shorter hemicellulose chains. FTIR spectroscopy shows that sterilisation results in the deacetylation of cellulose and the formation of new carbonyl groups, an increase in the total crystallinity index (TCI) and a decrease in the lateral order index (LOI) and the hydrogen-bond intensity (HBI).

Keywords: Cellulose; FTIR spectroscopy; Hemicelluloses; Pine wood; Size exclusion chromatography; Thermal modification.