Characteristics of bovine lactoferrin powders produced through spray and freeze drying processes.

Bovine lactoferrin (LF) powders were produced using spray drying and freeze drying. Industrially obtained fresh liquid-LF was used as starting material. The antioxidant capacity, solubility in water, moisture sorption behaviour, the extent of denaturation and changes in the secondary structural features of spray-dried (SDLF) and freeze-dried bovine lactoferrin (FDLF) powders were determined. The residual moisture content, water activity, particle size and amorphous/crystalline nature of the SDLF and FDLF were also measured. Results showed that both SDLF and FDLF powders had negligible denaturation and conformation changes compared to the liquid-LF. Both SDLF and FDLF showed type II sorption behaviour with almost identical monolayer moisture content. The SDLF powders were amorphous in nature with >98% solubility in water. The antioxidant activity of SDLF was similar to that of the liquid-LF while it was ∼6% less in FDLF. Based on the residual moisture content, water activity, solubility and preservation of secondary structure of LF in resultant powders, a spray drying process with 180°C inlet and 95°C outlet temperature was found to produce similar or better quality LF powders compared to the ones produced through a freeze drying process.