Concentration changes of aroma components in plain and probiotic yoghurt during storage

In this study, two types of yoghurt, plain yoghurt and probiotic yoghurt purchased from Croatian and Slovenian market, were stored for up to 25 days at two different temperatures (+4 ºC, +20 ºC). Samples were analyzed every 5 days and changes in acetaldehyde, ethanol and diacetyl content were determined. At the same time sensory evaluation was carried out. The aim of this study to show changes in concentrations of some flavor compounds and sensory quality in both yoghurt types during storage as a function of storage time and temperature. The results indicate that the equal changes in aroma compounds in both yoghurt types were result of the same microorganisms present in both yoghurt types (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus which have the greatest influence on the aroma, while the addition of other microorganisms has mostly probiotic effect