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

U ovom radu su korišteni uzorci običnog i probiotičkog jogurta s hrvatskog i slovenskog tržišta. Uzorci su čuvani 25 dana na dvije različite temperature (+4 °C, +20 °C), a svakih 5 dana uzimani su uzorci za određivanje sastojaka arome (acetaldehid, etanol i diacetil). Istovremeno je provedena i senzorska procjena. Svrha ovog istraživanja bila je utvrditi promjene koncentracija pojedinih tvari arome i senzorske kakvoće običnog i probiotičkog jogurta tijekom skladištenja ovisno o temperaturi i trajanju skladištenja, te utvrditi u kojoj mjeri su te promjene arome progresivnije s obzirom na različitost uzoraka. Dobiveni rezultati ukazuju da je smjer promjena udjela sastojaka arome identičan u obje vrste jogurta uglavnom zbog bakterija jogurtne kulture (Lactobacillus delbrueckii subsp. bulgaricus i Streptococcus thermophilus) koji značajno utječu na tvari arome, dok prisutnost probiotičkih bakterija ima uglavnom terapijski učinak.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