Effect of trehalose and lactose as cryoprotectant during freeze-drying, in vitro gastro-intestinal transit and survival of microencapsulated freeze-dried Lactobacillus casei 431 cells

A novel microencapsulation technique for Lactobacillus casei 431 cells was developed, and the bacterial stability was studied. Cryoprotective solutes were incorporated in the encapsulation mix to improve freeze-drying survival. The losses of viable cells during drying were recorded as 1.7, 0.84 and 0.38logColony-forming units (cfu)/g for control and samples with trehalose and lactose, respectively. During the simulated gastric-intestinal transit, trehalose and lactose contributed to higher survivals of 3.1 and 3.0logcfu/g, respectively, in gastric fluid and 1.3 log and 0.9logcfu/g, respectively, in 1% bile extract solution. Higher temperature storage was found to be detrimental for cell viability.