The Effects of Temperature and Milk Fat Content on the Electrical Conductivity of Kefir during the Incubation

Abstract

In this study, the relationships between the electrical conductivity and temperature for different milk fat contents were investigated during the incubation of kefir. For kefir production, three milk samples at different fat contents (0.15, 1.7 and 3.0%) and two incubation temperatures (25 °C and 35 °C) were selected. The inoculum level was 2%. The kefir fermentation time was approximately 10 h and the pH of kefir samples were 4.4 in the last stage. The test results showed that electrical conductivity (EC) increased at both the temperatures. The average EC values of non fat milk kefir were in the range of 4.72 mS/cm – 6.4 mS/cm at 35 °C, and 4.72 mS/cm – 5.71 mS/cm at 25 °C. The average EC values of full fat milk kefir were in the range of 4.84 mS/cm – 6.41 mS/cm at 35 °C, and 4.84 mS/cm – 5.63 at 25 °C. The average EC values of low fat milk kefir were in the range of 4.54 mS/cm – 6.39 mS/cm at 35 °C, and 4.54mS/cm – 5.5 mS/cm at 25 °C. Electrical conductivity of samples showed little improvement at low incubation temperature and fat content. Statistically, there was a significant difference (p < 0.05) in EC among samples.