Effect of natural starter culture activity on ethanol content in fermented dairy products

Abstract

The influence of kefir grains' activation time on kefir pH changes and ethanol production was investigated. The proposed exponential pH model was used successfully to describe any decrease in pH during 24 h fermentation. Furthermore, the influence was investigated of differently active kefir grains on the correlation between ethanol and yeast population in grains and kefir drink respectively. Results showed that longer-activated grains produce more ethanol and have a larger number of yeasts than grains, which are activated for only a few days. The number of yeasts in a kefir product also increases over the grains' activation time. © 2009 Society of Dairy Technology.