Extraction of ferulic acid and feruloylated arabinoxylo-oligosaccharides from wheat bran using pressurized hot water

Abstract Pressurized water was tested as solvent for the hydrolysis and extraction of Ferulic acid (FA) and feruloylated arabinoxylooligosaccharides (F-AXOS) from destarched wheat bran (DWB). Results were dependent on the severity factor of the process (combination of temperature and time), obtaining the maximum extraction yields at 200°C and 3.5 min. 78% of the total FA was successfully extracted, being 17% in its free form and the rest, covalent ester-bounded to arabinoxylans. Under such conditions, 80% of the arabinoxylans are extracted with a degree of FA esterification of 1.34 g FA/100 g AXOS, and an average molecular weight of 1,3·104 Da. Pressurized Microwave Assisted Extraction was also studied to evaluate potential intensification of the process using microwaves. However, no significant differences were observed with the microwave heating. Residual solid after extraction was mainly composed by lignin and cellulose (56% and 21%, respectively) showing that hot compressed water technology can be integrated in the first steps of a biorefinery for the total valorization of the wheat bran.