Abstract:

This work studied the effects of fructooligosaccharide (QHT-90 FOS) and galactooligosaccharide (QHT-60
GOS) with various concentrations on the viable count of Lactobacillus helveticus MB2-1, titratable acidity and viscosity
of fermented milk during fermentation and storage. The results showed that QHT-90 FOS had a better ability to increase
the proliferation of Lactobacillus in fermented milk than QHT-60 GOS. When the concentration of QHT-90 FOS was
1.5 g/100 mL in 12-hour fermented milk, the viable count of L. helveticus MB2-1 reached 4.44 × 109 CFU/g.
Oligosaccharides with different structures had similar effects on titratable acidity and viscosity of different samples.
QHT-90 FOS had the ability to protect L. helveticus MB2-1. Under the storage condition of 4 ℃, the viable count of
L. helveticus MB2-1 decreased by only 11.90%. After 14 days of storage, the titratable acidity remained unchanged, and the
viscosity stayed at a high level of 9 000 mPa·s.

Key words: oligosaccharides, fermented milk, fermentation period, storage period