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

Abstract

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