Isolation of free casein amino acids from their water-soluble Cu complexes is effected by reaction with H2S in an aq. medium (opt. weakly acidified with acetic acid) contg. =33 mole% t-BuOH. Use of an aq. t-BuOH medium inhibits colloidal CuS formation, giving products with a Cu content of 20 ppm, suitable for use in the pharmaceutical and foodstuffs industries, without the need for ultrafiltration.
展开▼