Microencapsulation of Lactobacillus plantarum (mtcc 5422) by spray-freeze-drying method and evaluation of survival in simulated gastrointestinal conditions

Spray-drying (SD) and freeze-drying (FD) are widely used methods for microencapsulation of heat-sensitive
materials like probiotics for long-term preservation and transport. Spray-freeze-drying (SFD) is relatively a
new technique that involves spraying a solution into a cold medium and removal of solvent (water) by
conventional vacuum FD method. In this study, the SFD microencapsulated Lactobacillus plantarum powder
(1:1 and 1:1.5 core-to-wall ratios of whey protein) is compared with the microencapsulated powders produced
by FD and SD methods. The SFD and FD processed microencapsulated powder show 20% higher cell
viability than the SD samples. In simulated gastrointestinal conditions, the SFD and FD cells show up to 4 h
better tolerance than SD samples and unencapsulated cells in acidic and pepsin condition. The morphology
of SFD samples shows particles almost in spherical shape with numerous fine pores, which in turn results in
good rehydration behaviour of the powdered product.