Abstract:

On the basis of a fact that β-lactoglobulin (β-LG) can be conjugated to chitosan due to electrostatic interactions under acidic pH condition, and deconjugated from the polysaccharides under alkaline pH condition, β -LG was isolated from whey powder by the addition of chitosan. In order to maximize extraction yield, crucial affecting factors of β -LG extraction which were determined by single factor method were optimized using orthogonal array design. Results showed that a final product with a β -LG purity of 95.12% and a yield of 93.65% was obtained through the optimal extraction procedure based on conjugation with the addition of 2 mg of chitosan to 1 ml of whey powder solution at pH 6.2, followed by deconjugation in 0.4 mol/L NaCl solution at pH 11.

Key words: chitosan, β-lactoglobulin, electrostatic interactions, whey powder