Abstract:In order to remove the excessive salt from zein glycopeptide solution, the nanofiltration membrane with a molecular weight cut-off of 200 was applied for the desalination of antioxidant zein glycopeptide solution. The membrane flux, Na+ mass fraction, desalination rate, electrical conductivity, recovery rate of short peptide of zein glycopeptide solution, and the free radical scavenging rate and Fe2+-chelating activity of products after nanofiltration were studied to determine the nanofiltration desalination process of zein glycopeptides. The results showed that zein glycopeptides was desalted by a 200 nanofiltration membrane was carried out continuously for 5 times nanofiltration under 2.0 MPa at 20 ℃ with each nanofiltration volumetric concentration factor of 2. After 5 times of nanofiltrations, the electrical conductivity of retentate was decreased by 60.87%. The desalting rate and the recovery rate of short zein glycopeptide were 81.60% and 96.97%, respectively. The hydroxyl radical scavenging rate of desalted zein glycopeptide was increased from 11.25% to 15.85%, and the 1,1-diphenyl-2-picrylhydrazyl radical scavenging rate and Fe2+-chelating activity were decreased by 11.83% and 46.07%, respectively. Moreover, the 200 nanofiltration membrane could remove 55.54% of unreacted D-glucosamine in the glycosylation reaction product, playing a triple role of desalination, desugarization and concentration.
