Synergistic effects of Eudragit® L100 and trehalose in bacterial viability retention during single droplet drying.

Improving the viability and intestinal accessibility of probiotic bacteria in spray-dried powders is a critical challenge. Our previous studies have revealed that the intestinal-targeted delivery of Eudragit® L100 (L100)-trehalose (Tre)-Lacticaseibacillus rhamnosus GG (LGG) particles was influenced by drying conditions, demonstrating the potential of L100-Tre-LGG as a spray-dried probiotic product. In this study, we explored the synergistic effect of L100 and Tre on LGG viability by analysing droplet evolution and drying kinetics using a single droplet drying technique. The results showed that the addition of L100 affected particle morphology, crust formation, rehydration and hygroscopic properties, all of which were linked to LGG viability. In addition, monitoring drying kinetic parameters such as temperature and mass revealed that L100 modulated the droplet drying kinetics, synergizing with Tre to increase LGG viability retention. This study found that the presence of L100 significantly improved LGG viability during thermal convective drying and affected the particle formation behaviour and drying kinetics of droplets. The research provides a theoretical basis for developing highly viable spray-dried probiotic powder systems.