Spray Drying of a Vaginal Probiotic Strain of Lactobacillus acidophilus

Abstract

This work presents a study of the spray-drying process of a vaginal strain of Lactobacillus acidophilus in order to enhance the cells viability and probiotics properties during storage. The results show that the powder obtained presents dried strain viability in the range of 108–109 (CFU/g) with product moisture content below 10%. Additionally, the dehydrated strain maintains its viability during two months when stored at 4°C, although its viability drops 1 order of magnitude when stored at 25°C for 1 month. It was verified that the range of operating conditions studied during drying (e.g., pressure, feed concentration, and additive) did not affect bacteria viability, except for increased air-drying temperature. The strain did not suffer important changes in its identity, morphology, or probiotic properties due to the spray-drying process. Using the mass-energy balance in the dryer, the volumetric overall heat transfer coefficient was determined as 2 × 10−4 (kg water evaporated/m3 K s) for the experimental drying system.