Hempseed polysaccharide (Cannabis sativa L.): Physicochemical characterization and comparison with flaxseed polysaccharide

The whole hempseed contains about 27.6% of fiber, of which 5.4% and 22.2% are soluble and insoluble fiber, respectively. The defatted hempseed meal contains about 42.6% of total fiber. Despite the abundant amount of fiber in the hempseed, the application of hempseed polysaccharides (HSP) is currently limited in the food industry. It is necessary to understand their physicochemical properties to extend their food applications. Hence, the objective of the current study is to investigate the physicochemical properties of soluble hempseed polysaccharides in comparison with flaxseed polysaccharides. The physicochemical properties, including molecular weight distribution, shape conformation, total sugar content, uronic acid content, rheological properties, and emulsification properties, were evaluated. The results indicated that the HSP contains about 33% uronic acids, 53% total sugars, and possesses an oblate ellipsoidal shape (Rg = 23.07 nm, Rh = 22.61 nm). Compared to flaxseed polysaccharides and pectin, the HSP showed a high surface active behavior at concentrations above 0.5% (w/v). The dynamic flow curves demonstrated the shear thinning behavior of HSP at the low shear rate range (0.01-10 s-1), followed by a Newtonian behavior at the high shear rate range. The HSP exhibited a weak gel property and an elastic nature. The emulsion stability of HSP and flax polysaccharide did not show a significant difference. The effects of pH and heat treatment on HSP stabilized emulsion were insignificant compared to flax polysaccharides. Finally, the freeze-thaw stability of HSP was inferior compared to flaxseed polysaccharides and pectin. The study has revealed that the HSP could be a potential emulsifying agent in the food system.