Manufacturing of reverse osmosis whey concentrates with extended shelf life and high protein nativity

The suitability of a two-step preservation process for whey concentrates consisting of cold microfiltration (MF) (1.4 μm pore size) and gentle heat treatment was investigated. The purpose was to produce reverse osmosis (RO) whey concentrates [dry matter (DM) contents: 12-30%] showing high native protein levels and sufficient shelf life as a substitute for whey powder. Strong bacterial reduction of 4.8-6.0 log cycles could be achieved by MF in whey concentrates with 12, 18 and 24% DM. Concurrently, low whey protein denaturation of 0.1-6.6% and 2.3-12.7% was found after pasteurisation at 75 °C and 80 °C, respectively, for 30 s. Microbiological shelf life of the whey concentrates was at least 4 months at 4 °C storage temperature. The applied process is suitable to produce extended shelf life (ESL) whey concentrates with DM of up to 24% that might serve as energy efficient substitutes for whey powder.