Enhanced survival of spray-dried microencapsulated Lactobacillus rhamnosus GG in the presence of glucose

Abstract The survival of spray dried Lactobacillus rhamnosus GG (LGG) preparations encapsulated in whey protein isolate (WPI)–maltodextrin, WPI–maltodextrin–glucose, WPI–inulin, and WPI–inulin–glucose mixtures during storage at 25 °C (11%, 57% and 70% relative humidity, RH) was examined. The glass transition temperature of each encapsulant formulation was also assessed. RH was most important for maintaining viability over time; the inclusion of glucose improved viability, irrespective of when all formulations were in a glassy or rubbery state. When LGG microcapsule powders were stored at the same RH, the addition of glucose in the encapsulant formulation had a greater influence on survival of LGG during storage than the maintenance of a glassy state. Both the maintenance of a glassy state during storage and the incorporation of glucose in the encapsulant formulation were required for optimal survival of probiotic microcapsule powders prepared from fresh cultures. Practical significance The incorporation of glucose into the encapsulant formulation prior to spray drying of protein-carbohydrate based LGG formulations improves the survival of LGG during long term storage.