Comparison of Fermentation Properties of Lactobacillus acidophilus in Cow and Goat Milk

Fermentation properties such as acid-or flavor-producing capability and proliferation pattern were determined for Lactobacillusacidophilus 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 Lactobacillusacidophilus(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 Lactobacillusacidophilus 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 Lactobacillusacidophilusafter 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.