The viability of the probiotic strain Lactobacillus acidophilus DSM 20079, after its passage through the
simulated gastric and pancreatic juices, was evaluated as function of its pre-growth in a medium containing
the known prebiotics pectin or inulin, and was compared to glucose used as control. The presence
of pectin or inulin did not affect the growth (12.11log10 colony forming units/mL and 12.08log10 colony
forming units/mL for pectin and inulin respectively versus 12.22log10 colony forming units/mL obtained
for glucose). Pectin and inulin, in contrast to glucose, induced cell stress resistance against gastrointestinal
juices (Dlog10 1 and 2 colony forming units/mL respectively, versus Dlog10 4.5 for glucose). The data
were confirmed by the analysis of the protein pattern following stress treatments which, in the case of
microbial cells grown with glucose, revealed a relevant protein degradation after the double passage
through simulated gastric and intestinal juices. An impressive metabolic change, as function of the
growth conditions, was demonstrated by analyzing the proteomic profile with a m-2DE system, used
herein for the first time as evaluation tool of prebioticeprobiotic interactions. The analysis revealed
a different pH protein distribution that was mostly acidic in the presence of pectin and neutral-alkaline
in the presence of inulin. Both prebiotics stimulated the production of butyrate, a relevant healthy biomolecule
not detectable in the presence of glucose, that was measured by HPLC analysis to be 14.5 fold
higher after growth in the presence of inulin, as compared to pectin. Three specific proteins were
detected at pH 6 after growth in the presence of pectin or inulin. They could be correlated to the stress
resistance and/or to the production of butyrate, the common phenotypic characteristics induced in the
bacterial strain by the two prebiotics.