Abstract
Summary: Casein is well known as a good protein emulsifier and β‐casein is the major component of casein and commercial sodium caseinate. Dye affinity adsorption is increasingly used for protein separation. β‐Casein adsorption onto Reactive Red 120 attached magnetic poly(2‐hydroxyethyl methacrylate) (m‐PHEMA) beads was investigated in this work. m‐PHEMA beads (80–120 µm in diameter) were produced by dispersion polymerization. The dichlorotriazine dye Reactive Red 120 was attached covalently as a ligand. The dye attached beads, having a swelling ratio of 55% (w/w) and carrying different amounts of Reactive Red 120 (9.2 µmol · g^−1^−39.8 µmol · g^−1^), were used in β‐casein adsorption studies. The effects of the initial concentration, pH, ionic strength and temperature on the adsorption efficiency of dye attached beads were studied in a batch reactor. The non‐specific adsorption on the m‐PHEMA beads was 1.4 mg · g^−1^. Reactive Red 120 attachment significantly increased the β‐casein adsorption up to 37.3 mg · g^−1^. More than 95.4% of the adsorbed β‐casein was desorbed in 1 h in a desorption medium containing 1.0 M KSCN at pH 8.0. We concluded that Reactive Red 120 attached m‐PHEMA beads can be applied for β‐casein adsorption without significant losses in the adsorption capacities.
Chemical structure of Reactive Red 120.
magnified imageChemical structure of Reactive Red 120.