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

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