E. Selmer-olsen et al., Effect of protective solutes on leakage from and survival of immobilized Lactobacillus subjected to drying, storage and rehydration, J APPL MICR, 87(3), 1999, pp. 429-437
When lactic acid bacteria are used industrially as fermentation starters it
is important to obtain stable and highly viable bacterial cultures. Six st
rains of Lactobacillus encapsulated in Ca-alginate gel beads were investiga
ted to determine whether dehydration, storage and rehydration may inflict i
njury. A negative relationship between leakage of lactate dehydrogenase and
survival rates was found. Mesophilic lactobacilli showed only negligible l
eakage compared with thermophilic strains when dehydrated at 30 degrees C t
o a level of 0.11 g H2O (g dry wt)(-1). The choice of an appropriate suspen
ding medium to be introduced before drying was therefore very important for
thermophilic lactobacilli in order to increase the survival rates during d
ehydration, storage and rehydration. The osmoregulatory solutes tested were
adonitol, betaine, glycerol and reconstituted non-fat milk solids (NFMS).
Less injury was inflected during dehydration for Lactobacillus helveticus w
ith adonitol, glycerol and NFMS. Survival rates for the strains subjected t
o immobilization, dehydration, storage and rehydration varied with the stra
in and the protective solute when fluidized-bed drying was used at 5 degree
s C to a level as high as 0.34 g H2O (g dry wt)(-1). Non-fat milk solids ga
ve the best protection for thermophilic lactobacilli, while adonitol and NF
MS were best for mesophilic lactobacilli.