Colour changes in oakwood during vacuum drying by contact: Studies on antioxydant potency and infrared spectras in surfaces

Manufacturing appearance products generally requires high-quality wood, which is expensive and not as abundant as lower-grade wood. Th e formation of coloured substances from phenolic compounds oxidized with air and the formation of dark materials from hydrolysis have been considered the causes of discolouration during drying. In order to reduce color changes, vacuum drying process can be used, which off ers several advantages. In this work, antioxidant activities were evaluated from dust of oak-wood after vacuum drying and convective drying by using ABTS+  cation (AAEAC method), DRIFT spectras are obtained, Cielab parameter were obtained with a colorimeter, and vacuum drying kinetics with conductive heating are presented for diff erent drying conditions. Th e conductive heat source is maintained at diff erent temperatures and pressure in the chamber is controlled at diff erent intervals (60-100, 150-250, and 250-300 mbar). We found that lightness increases as temperature increases and C=O formation increases as antioxidant potency decreases.