The protective effect of monosodium glutamate on survival of Lactobacillus rhamnosus GG and Lactobacillus rhamnosus E-97800 (E800) strains during spray-drying and storage in trehalose-containing powders

The use of trehalose as a means of preserving Lactobacillus rhamnosus GG (LGG) and L. rhamnosus E-97800 (E800) during spray-drying and the effects of incorporated monosodium glutamate (MSG) in the carrier medium on the survival rates during drying and storage were examined. E800 was more resistant to heat than LGG in 20%, w/w, trehalose; the d-values at 65 °C were 14 s and 5.1 s, respectively. An air outlet temperature of 65–70 °C was taken as optimal for the drying process, as the resultant moisture levels in trehalose containing these bacteria were 4.1% (w/w) and 3.79% (w/w) with corresponding viable counts of 3.65 × 108 cfu mL−1 and 1.80 × 109 cfu mL−1, respectively. The presence of MSG increased the final viable counts of LGG and E800 to 3.05 × 109 cfu mL−1 and 1.30 × 109 cfu mL−1, respectively. Survival of LGG and E800 remained constant at a minimum level of ∼108 cfu mL−1 during storage at 25 °C in trehalose–MSG medium.