To determine product moisture content, precisely weigh 100 milligrams of the dried product and place it in the titration vessel of Karl Fisher Equipment. Initiate the biamperometric titration of water present in the sample by pressing the initiation button. To determine water activity, weigh 0.6 grams of dried product in the sample compartment of the hygrometer at 25 degrees Celsius and close the equipment cover.
For determining probiotic viability, dilute bacterial culture in nine milliliters of peptide water and vortex until complete dispersion. Perform serial decimal dilutions with diluted bacterial culture in nine milliliters of saline solution. Seed the dilutions onto De Man, Rogosa and Sharpe agar plates and incubate at 37 degrees Celsius for 24 to 48 hours.
After incubation, count the colony forming units or CFU using a colony counter with magnifying lens. Calculate the probiotic viability in the dried product using the given equation to express the number of viable cells in CFU per gram of product dispersion. The results of the spray drying of the probiotics at 80 degree Celsius showed that the distinct drying aids promoted efficient protection of the probiotic cells.
The increase in spray drying temperature tended to decrease the probiotic viability and reached nearly 80%at 160 degrees Celsius. However, the powder yield remained around 50%throughout all the temperatures. The powder's moisture content and water activity decreased conversely with the spray drying temperature.
