Effects of combination processes on the extraction of pectins from rapeseed cake (Brassica napus L.)

In this study, rapeseed cake (RSC) was used as a source of pectins due to its high carbohydrate content. Different combinations of treatments were applied to investigate the effect of combination processes on the extraction of pectin from RSC. The treatments chosen for combination were a fat removal process (FRP) (solvent extraction using an alcohol–benzene mixture), a chemical treatment (CT) (hydrolysis using 1% hydrochloric acid), and an enzymatic hydrolysis (EH). After the combined processes, pectins were extracted by isopropanol/ethanol precipitation and the residues were analysed by HPLC or an elemental analyser. The pectin yields and galacturonic acid contents were increased by FRP because 72.13% of the total fat was removed; additionally, EH had a similar effect. However, CT decreased the yields because the treatment was too harsh and the galacturonic acid broke down. Pectin yields and galacturonic acid contents were highest in the combination process FRP/EH (6.23% and 64.23%, respectively).