Effect of incubation temperature, heat treatment and milk source on the yoghurt kinetic acidification.
Despite the crucial importance of the acidification step for the yoghurt manufacture, few research studies have deeply focused on the understanding and characterization of this biotechnological and complex phenomenon. In order to address this important topic, this paper aims to (a) evaluate the effect of the type of milk (caprine, bubaline and bovine), incubation temperature (39oC, 42oC and 45oC) and the applied thermal process (T1: pasteurization at 72oC for 15s and T2: pasteurization at 72oC for 15s followed by additional thermal treatment at 90oC for 15min) on the acidification profile and kinetic parameters Vm (maximum acidification rate), Tm (time to reach Vm), and Te(time to reach pH 4.6) and (b) to estimate the relationship between these selected kinetic parameters (Vm, Tm, Te). Results showed that each type of milk presents a particular behavior during the acidification, which might be related to their chemical composition. It was also possible to observe that the type of milk has a significant effect on Vm and the thermal treatment can also influence the parameter Tm. Overall, our results suggest that the processing parameters already established for cow’s milk cannot be directly extrapolated to other types of milk.