Green extraction processes for the valorization of paulownia residual biomass

Résumé

The Paulownia genus includes fast-growing tree species with great adaptability. In recent years, different plantations have been developed in Spain for the exploitation of Paulownia wood. However, there are residual fractions, such as bark, leaves and flowers (lignocellulosic materials that represent approximately 50% by weight of biomass) that are not used and that are the object of study of this work. The use of different extraction technologies (microwave assistance, water under pressurized conditions and carbon dioxide under supercritical conditions) and their combinations are proposed to obtain soluble fractions enriched in bioactive compounds. The composition of the solubilized and residual fractions is evaluated in terms of phenol and mono- and oligosaccharide content and the antioxidant properties of the free extracts are evaluated as radical scavenging capacity. To achieve a comprehensive use of these fractions, a possible application of the obtained solubles are proposed by the preparation of gelling complexes whose rheological properties are characterized.