ABSTRACTThe effect of pretreatment upon the composition and physicochemical and functional properties of whey, ultrafiltration (UF) retentate and freeze‐dried and spray‐dried whey protein concentrates (WPC) was investigated. Pretreatment was by cooling cheese whey to 0‐5°C, adding calcium chloride, adjusting to pH 7.3, warming to 50°C, and removing the insoluble precipitate that formed by centrifugation or decantation. UF permeation flux rate of pretreated whey was about double that for control whey. Pretreated whey was essentially turbidity free, contained 85% less milkfat, 37% more calcium and 40% less phosphorus than whey. Pretreated whey WPC proteins were slightly more soluble at pH 3, but less functional for emulsification than whey WPC proteins. Neither whey WPC proteins nor pretreated whey WPC proteins was functional for foaming at 6% protein concen