As part of the master's thesis, we studied the microbial composition of 17 kefir grains from different geographical areas (11 of Slovenian, 3 of English, 1 of German and 2 of Russian origin) and the kefirs produced from these grains using the traditional method. The aim was to determine whether grains from different areas differ from each other and how this affects the sensory properties of kefir. The composition of the microbial population was determined using conventional microbiological methods, focusing on lactic acid bacteria and yeasts, which were identified using the MALDI-TOF MS technique. We found that the microbial population of kefir grains is different from that of kefir. Lactic acid bacteria, particularly Lb. kefiranofacines and Lb. kefiri, dominated in the kefir grains, while the kefir samples contained mainly cocci, such as Lc. lactis, E. durans, and Ac. fabarum, which belongs to the acetic acid bacteria. Both the kefir grains and kefirs samples had the lowest yeast counts, with the most commonly identified species being Kaz. unispora, Kaz. turicensis, and Kluy. marxianus. Sensory analysis of the kefir samples, fermented at 21 °C and 25 °C, revealed better evaluations for kefirs fermented at the lower temperature. Furthermore, we determined the physicochemical properties, including pH value, lactose concentration, and levels of lactic and acetic acid. Samples fermented at a higher temperature contained higher acid concentrations than those fermented at a lower temperature.
|
