Optimising deproteinisation methods and effect of deproteinisation on structural and functional characteristics of flaxseed gum

Summary In the current study, deproteinisation rate (DPR) and carbohydrate loss ratio (CLR) in flaxseed gum (FSG) were compared as indexes by using four different deproteinised methods, that is sodium chloride (NaCl), trichloroacetic acid (TCA), hydrochloric acid (HCl) and calcium chloride (CaCl 2 ). In addition, the effect of deproteinisation on physicochemical, functional and structural characteristics (FTIR, 1 H NMR and SEM analysis) of deproteinised flaxseed gum (DFSG) was further examined. The results revealed that HCl and TCA methods had better ability of deproteinisation (97.83% and 96.21%) but resulted in higher CLR (27.66% and 24.19%), while CaCl 2 method excelled over the NaCl method in DPR (94.7% and 88.6%) and CLR (4.90% and 4.21%), respectively. Flaxseed gum showed significant functional properties even after deproteinisation and exhibited resolved resonances for both ring and anomeric protons in 1 H NMR spectra. The characteristic groups in FTIR spectra were retained after deproteinisation.