Selective Concentration of Bovine Immunoglobulins and α‐Lactalbumin from Acid Whey using FeCl 3

Immunoglobulins and α‐lactalbumin of acid whey were concentrated in supernatant and precipitate when FeCl 3 was added at pH 4.2 and 2.8, respectively. Optimized conditions of pH 4.2 were preferable because of higher retention of immunochemical activity of immunoglobulins. In acid whey treated with 7.5 mM FeCl 3 at pH 4.2 and 4°C, 90% of β‐lactoglobulin coprecipitated with serum albumin while 70% of immunoglobulins (92% immunochemically active IgG) and 95% of α‐lactalbumin were retained in the supernatant. More than 98% of added iron was subsequently eliminated as precipitate by holding the treated whey at pH 8‐9 and 4°C, without losing immunochemical activity of immunoglobulin G, in addition to retained activity of immunoglobulins A and M.