The effect of time and temperature on the extraction of xylose and total phenolic compounds with pressurized hot water from hardwood species used for pulp and paper production in the South of France

Abstract Study of the extraction of xylose and total phenolic compounds (TPC) from chestnut and beech with pressurized hot water was carried out following the experimental design methodology using time (30 min–90 min) and temperature (120 °C–170 °C) as factors. Results are compared under specific conditions with poplar and oak and with a mixture of the four species, representative of an industrial inlet used. Higher TPC extraction yield of chestnut tree (10%) than of beech (2%) is observed, with no effect on the extraction yield which becomes constant with time for chestnut, while it increases for beech as the temperature rises above 150 °C. At higher temperature, the co-extraction of hemicelluloses reduces the purity of the TPC in the chestnut extract, from 60% at 120 °C to 25% at 170 °C. In the case of the beech, TPC purity remains low. Chestnut and oak are relevant species for recovery of both TPC and hemicelluloses.