Bile salts can also greatly affect the viability of lactic acid
bacteria (Bustos, Raya, Bru, Valdez, & Taranto, 2011). The composition
of human bile juice is not exactly the same as that of
the 0.3% bile salts solution. In this study, L. delbrueckii UFV
H2b20 survived acid treatment (pH 3.0), cultured in MRS
broth, with or without 0.3% bile salts, for the assessment of
its tolerance to bile. After 12 h cultivation, effects of bile salt
on the growth of L. delbrueckii UFV H2b20 were observed
(Table 3). The growth of L. delbrueckii UFV H2b20, incorporated
in three ice cream formulations, in MRS broth supplemented
with bile salts was not significantly affected. This ability to
grow in the presence of bile salts demonstrates that L. delbrueckii
resists very well to ice cream production process
and storage. The use of inulin to replace fat does not affect
the protection of these stress conditions. Resistance of L. delbrueckii
UFV H2b20 to the action of bile salts seems to depend
on the physicochemical properties of the cellular envelopes.
Alamprese et al. (2002) reported that freezing and thawing,
as well as frozen storage, damaged cell membrane, rendering
the microorganisms sensitive to bile salts. Therefore, agitation
and the consequent physical forces used in the production
of ice cream in batch freezer may have caused
additional physical damages to the cells and increased the
exposure of cell to bile.