Figs. 3A and 4A show the chromatographic profiles of green and
black tea samples, respectively, before the treatment with S. thermosphilus
and L. bulgaricus yogurt bacteria. The chromatograms
showed good separation of the six phenolic compounds allowing
their identification and quantification easily with a predominance
of GCG and EC.
After the treatment of the same samples with the yogurt bacteria,
the chromatograms obtained showed no significant modification
(P < 0.05) of the phenolic compounds of both green and
black tea samples (Figs. 3B and 4B. Table 1 gave the composition
of phenolic compounds in inoculated and non inoculated tea samples.
The results obtained give a clear confirmation that the yogurt
bacteria did not affect significantly (P < 0.05) the composition of
the phenolic compounds of green and black teas.
Before the beginning of production and storage trials, preliminary
studies were conducted to see the effect of tea addition to milk
on acidity during fermentation. The acidity of milks dropped as expected
over the 6 h period of incubation and no significant (P < 0.05) differences (Fig. 5) in acidity were observed among the
treatments, indicating that tea neither supported nor impeded lactic
acid production by S. thermophilus and L. bulgaricus at this stage