Water Adsorption Isotherms and Storage Stability of Freeze-Dried Bovine Colostrum Powder

Moisture adsorption isotherms of freeze-dried bovine colostrum powder were obtained using the gravimetric method at three temperatures (15, 25, and 35 degrees C) in the water activity range of 0.11-0.86. The moisture adsorption isotherms of freeze-dried bovine colostrum powder showed a sigmoid isotherm curve typical of the type II BET classification shape. The Guggenheim-Anderson-de Boer and Brunauer-Emmett-Teller models were recommended to fit experimental data well. The shelf life of freeze-dried bovine colostrum powder packaged in aluminium-laminated polyethylene pouches was evaluated for 243 days, and the storage stability was investigated when stored at 25 degrees C and 50% relative humidity. A slight increase in moisture content, a linear increase in color difference, and a slight decrease in IgG concentration were found within 60 days storage under the above-mentioned conditions.