Influence of heat treatment on antioxidant properties and colour stability of beech and spruce wood and their extractives

Heat treatment of wood in absence of oxygen and under mild conditions allows for obtaining a material with many interesting properties, such as enhanced dimensional stability and increased biological durability. The aim of this work was to study the influence of a thermal treatment on the antioxidant activity of the extractives of two wood species - beech and spruce - by using the DPPH method and quantifying the formation of phenoxyl radicals using ESR as wood and extractives are exposed to light irradiation. The relationship between the kinetics of formation of free radicals in the extracts of heat-treated wood and the antioxidant properties is discussed. Links with colour modification are discussed.