Comparison of energy consumption and probiotic stability with pilot scale drying processes

The production of dried probiotics offers multiple advantages including expanded storage options, ease of transportation, enhanced stability, formulation support, and incorporation into a variety of finished products. As probiotic use and application areas increase, the demand for lower production costs and increased product stability follows. The most common methods for drying include lyophilization and spray drying. Lyophilization offers high preservation of viability at the expense of production speed, while spray drying provides high throughput drying with greater loss of probiotic viability. Newer processes, such as electrostatic spray drying, have the potential to bridge the gap. The aim of this study was to evaluate the energy consumption and viability of Lacticaseibacillus rhamnosus GG (LGG) with pilot-scale conventional spray drying, electrostatic spray drying, and lyophilization. Energy consumption of the primary utilities was monitored along with LGG viability immediately and 8-12 weeks after drying. With regards to removal of water, conventional spray drying was the most energy efficient (1.2 kWh/L), followed by electrostatic spray drying (10.9 kWh/L) and lyophilization (16.9 kWh/L). When normalized against recovered viable LGG, electrostatic spray drying was the most efficient at 4.6 x 1010 CFU/kWh, followed by lyophilization and conventional spray drying at 1.1 x 1010 CFU/kWh and 4.8 x 107 CFU/kWh, respectively.