A different concentration of the selected substrates was added to each series of bottles as follows: three with 2%,4%, and 6% oat bran, three with 2%, 4%, and 6% buckwheat flour and one used as control without any addition. Each series of bottles were inoculated with 10 ml of each corresponding pre-culture. The pre-cultures were prepared by dissolving 1 g (~1011 CFU/g) of freeze-dried culture of L. rhamnosus IMC 501® or L. paracasei IMC 502® or SYNBIO® in 99 ml of MRS and UHT whole milk respectively. After inoculation, bottles were incubated at 37 °C in aerobic conditions. The pH was monitored every 2 h with a JENWAY 3510 pH meter (Stone Staffordshire,UK), until reaching pH 4.6 ± 0.03, corresponding to the end of fermentation.At the same time point, bacterial counts were performed by the pour plate technique in MRS agar