The ability of potentially probiotic strain Lactobacillus plantarum BfEL 92122 to
milk fermentation, acid & bile tolerance, bile salt hydrolase activity and the possibility to use
different levels of L. plantarum association with commercial yoghurt starter for the
manufacture of probiotic yoghurt were investigated. This strain exhibited ability on acid &
bile tolerance and bile salt hydrolase activity. Also, it coagulated milk after ~ 24 hr
incubation at 37○C, population reached 108 cfu/ml and the pH values ~ 4.6. Yoghurt made
with 2% commercial yoghurt starter which contain L. delbrueckii ssp. bulgaricus and
Streptococcus salivarius spp. thermophilus, 1:1 as a control (T1), probiotic yoghurt made
with 2, 2.5 and 3% bio-yoghurt starter which contain commercial yoghurt starter and L.
plantarum culture, 1:1 (T2, T3 and T4, respectively). Yoghurt treatments were assessed for
coagulation time, rheological properties, chemical analysis, microbiological quality and
sensory evaluation when fresh and during storage up to 14 days at ~ 5○C. T1 and T4 nearly
the same in coagulation time compared with T2 and T3, while progressive increase in acid
production during storage were observed in T1 compared with T2, T3 and T4 especially at
the end of storage. L. plantarum did not affect the growth of commercial yoghurt starter or
chemical composition of yoghurt. Addition of L. plantarum in yoghurt production along
with commercial yoghurt starter (T3 and T4) allowed to obtain yoghurts with an improve in
the rheological, sensory properties and numbers of potentially probiotic bacteria at desired
level 106 – 108 cfu/g. |
