Abstract:

Fermentation properties such as acid- or flavor-producing capability and proliferation pattern were determined
for Lactobacillus acidophilus in cow milk in comparison to cells in goat milk aiming to provide a useful guideline to develop
probiotic fermented milk and functional dairy products. The results showed that the maximum viable cell population of
Lactobacillus acidophilus (5.37 × 1010 CFU/mL) was obtained after 14 h of fermentation at 37 ℃ in goat milk and moreover, the
pH was reduced to 4.15, providing a titratable acidity of 120.00 ºT, and 18.25 mg/L of diacetyl and 11.23 mg/L of acetaldehyde
were produced. In contrast, the maximum viable cell population of Lactobacillus acidophilus was 9.33 × 109 CFU/mL
upon using cow milk instead of goat milk for fermentation under identical conditions and the pH was reduced to 4.17,
resulting in a titratable acidity of 110.90 ºT, along with the production of 17.77 mg/L of diacetyl and 9.85 mg/L of
acetaldehyde. No significant difference in diacetyl production or pH was observed for Lactobacillus acidophilus after 14 h
of fermentation in cow and goat milk (P ＞ 0.05), while there were a highly significant difference (P ＜ 0.01) in bacterial
proliferation and acetaldehyde production and a significant difference (P ＜ 0.05) in titratable acidity. Conclusion: Compared
with cow milk, Lactobacillus acidophilus has better fermentation performance in goat milk.

Key words: Lactobacillus acidophilus, cow milk, goat milk, fermentation properties