Influence of syrup with prebiotic on the growth of lactic culture

Abstract

The growth of Lactobacillus acidophilus and Streptococcus thermophilus when syrup rich in fructooligosaccharides (FOS) was incorporated to the fermentation medium as unique carbon source was evaluated. Syrup was added at 2, 3 and 6% to the Man, Rogosa and Sharpe medium broth and inoculated later with 2% v/v of a L. acidophilus monoculture or with a co-culture including L. acidophilus and S. thermophilus. Lactic acid formation, pH values and sugar contents were determined for samples collected at 8 and 24 h. Growth capacity of mono or co-culture was not affected in any of the used syrup proportions. The growth rate, expressed as the acidification capacity, evaluated at the different times, was favorable for both cultures; however, co-culture displayed a better behavior than monoculture. After 24 h fermentation, both cultures consumed preferentially mono and disaccharides components of the syrup for growth meanwhile the FOS fraction was intact.