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Advisor(s)
Abstract(s)
The determination of the best conditions of preparation
of a (tentatively) probiotic starter culture that
might be suitable for cheese making composed solely
of Bifidobacterium lactis Bo and Lactobacillus
acidophilus Ki is critical if a consistently reliable acid
production is to be achieved, especially because
bifidobacteria have stringent requirements for
growth. Therefore, we determined whether B. lactis
Bo and L. acidophilus Ki required or benefitted from
the addition of milk hydrolyzates (brought about by
proteinase or neutrase as the nitrogen source). The
growth and acid production of B. lactis in milk were
affected by the addition of proteinase-mediated
hydrolyzate and, to a lesser extent, by neutrasemediated
hydrolyzate; a higher degree of hydrolysis of
either hydrolyzate resulted in greater biomass increase
and greater acid production. This result suggests
that the poor growth of bifidobacteria in milk is
due partially to the lack of small peptides and free
amino acids. The rates of growth and acidification by
B. lactis were enhanced when cocultured with L.
acidophilus (1:1 inoculum ratio). Conversely, the
growth rates and acid production of L. acidophilus
were not positively affected by the addition of either
milk hydrolyzate. Although L. acidophilus grew
slowly, its proteolytic system was apparently able to
generate its own nitrogen source. Nevertheless, coculture
with B. lactis (1:1 inoculum ratio) led to enhanced
rates of growth and acidification when compared
with that of the single strain, suggesting some
degree of symbiosis between the strains.
( Key words: Bifidobacterium lactis Bo, Lactobacillus
acidophilus Ki, growth, milk hydrolyzate)
Description
Keywords
Pedagogical Context
Citation
Journal of Dairy Science. ISSN 0022-0302. Vol. 81 n.º 11 (1998), p. 2817-2825