The effect of dry matter and salt addition on cheese whey demineralisation

The high mineral load of whey limits its utilisation. Demineralisation is needed for further processing and food applications. We used a lab-scale electrodialysis unit to remove ions from ten model solutions of fresh or reconstituted whey with increased dry matter and sodium content. The drop of main whey cations (K+, Na+, Ca2+, Mg2+) was measured by capillary electrophoresis. Whey solutions with 7, 14, 21% (w/w) dry matter were demineralised in 35, 60 and 95 min, respectively. The total salt content decreased by 90–95%. After NaCl addition at 1, 2, 3% (w/w), more than 95% of all cations were removed in 45, 65 and 90 min, respectively. K+ and Na+ were removed the fastest in all solutions, their concentration decreased by 83–100%, Ca2+ and Mg2+ content decreased by 61–96%. These results demonstrate that mineral salts are effectively removed from whey even if it is concentrated and highly salted.