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Effects of Various Sugars Added to Growth and Drying Media upon Thermotolerance and Survival throughout Storage of Freeze‐Dried lactobacillus delbrueckii ssp. bulgaricus
Author(s) -
Carvalho Ana S.,
Silva Joana,
Ho Peter,
Teixeira Paula,
Malcata F. Xavier,
Gibbs Paul
Publication year - 2008
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp034165y
Subject(s) - sorbitol , lactose , fructose , sugar , lactobacillus , food science , mannose , freeze drying , lactobacillus delbrueckii subsp. bulgaricus , chemistry , growth medium , biology , biochemistry , lactobacillaceae , bacteria , fermentation , chromatography , genetics
The aim of this research effort was to investigate the role of various sugar substrates in the growth medium upon thermotolerance and upon survival during storage after freeze‐drying of Lactobacillus bulgaricus . Addition of the sugars tested to the growth medium, and of these and sorbitol to the drying medium (skim milk) was investigated so as to determine whether a relationship exists between growth and drying media, in terms of protection of freeze‐dried cells throughout storage. The lowest decrease in viability of L. bulgaricus cells after freeze‐drying was obtained when that organism was grown in the presence of mannose. However, L. bulgaricus clearly survived better during storage when cells had been grown in the presence of fructose, lactose or mannose rather than glucose (the standard sugar in the growth medium). A similar effect could not be observed in terms of thermotolerance; in this case, the growth medium supplemented with lactose was found to yield cells bearing the highest heat resistance. Supplementation of the drying medium with glucose, fructose, lactose, mannose or sorbitol led in most cases to enhancement of protection during storage, to a degree that was growth medium‐dependent.