Physicochemical and emulsification properties of flaxseed (Linum usitatissimum) albumin and globulin fractions.

The physicochemical and emulsification characteristics of flaxseed albumin and globulin protein fractions were determined in this study. Flaxseed protein meal was extracted with 0.5 M NaCl, and the extract dialyzed against water followed by centrifugation to obtain the globulin as a water-insoluble precipitate and albumin as the water-soluble albumin. Gel electrophoresis data indicate that the globulin is composed of several polypeptides in the 10-50 kDa range while albumin consisted mainly of the 10 kDa polypeptide accompanied by a minor content of 40 kDa. Amino acid analysis showed significantly (p < 0.05) higher levels of hydrophobic amino acids in the globulin, which was consistent with higher surface hydrophobicity when compared to the albumin. All the emulsions had monomodal oil droplet size distribution and wider ranges were directly related to bigger sizes, especially at low (10 mg/mL) protein concentration when compared to the 50 mg/mL.