Effects of conventional processing methods on whey proteins in production of native whey powder

Native whey, produced by microfiltration of skim milk, has great potential in infant nutrition and as a functional food ingredient; however, processes to produce whey powder using high temperatures can adversely affect protein quality. The individual effects of three critical processing steps were investigated: standard thermal pasteurisation, membrane concentration and spray drying on protein quality when performed under the mildest conditions considered feasible for industrial operation. HPLC-analysis was used to measure the degree of denaturation of the six most abundant whey proteins (β-lactoglobulin, α-lactalbumin, bovine serum albumin, immunoglobulins, lactoferrin and lactoperoxidase) before and after each processing step. Overall, denaturation was minimal throughout our tests, although the tendency to denature was unequal between the individual proteins and also varied between tested processing types and medium compositions. In the production of native whey with microfiltration, retentions varied greatly between the proteins but were not affected by pasteurisation of milk.