Flaxseed gum: Extraction, bioactive composition, structural characterization, and its potential antioxidant activity

Flaxseed gum (FSG) is a heteropolysaccharide consist of neutral and acidic components that makes up approximately 8% of seed mass. FSG was extracted from mixture of brown and golden varieties of flaxseeds by hot water extraction method. The molecular weight distribution, monosaccharide analysis, chemical composition, and surface morphology of FSG were scrutinized in the current study to get a better insight regarding this important polysaccharide. The average molecular weight was recorded as 1,322 kDa with a polydispersity ratio of 1.6 for Mw/Mn and 2.4 for Mn/Mz. High-performance liquid chromatography (HPLC) screening revealed that extracted FSG was comprised of rhamnose, arabinose, mannose, glucose, fucose, xylose, galactose, glucosamine, glucuronic acid, and galacturonic acid, of which mannose and glucosamine have not been reported previously. The antioxidant activities of FSG measured as DPPH, ABTS, reducing power, and total antioxidant activity clearly demonstrated the antioxidant potency of FSG. Fourier-transform infrared spectroscopy (FTIR) and the Nuclear magnetic resonance (NMR) (¹ H, ¹³ C) s pectra ratified the presence of functional groups typical for polysaccharide. PRACTICAL APPLICATIONS: Flaxseed gum is a natural carbohydrate polymar. This study provides useful information regarding antioxidant potential, chemical, and structural characterization of FSG. The availability of a gum is fully characterized with bioactive composition, structural features, and antioxidant potential provides a toolset for the practical application in the food or drug industry.