Changes of quality in yoghurt produced under magnetic field effect during fermentation and storage processes

Abstract

In this study, the changes in pH, titratable acidity, and organic acid contents of yoghurts produced under three different magnetic field intensities were investigated during the fermentation period. In addition, the yoghurts were stored for 15 d and changes in the physicochemical, microbiological, and sensory qualities of the yoghurts were investigated. During fermentation, the pH values of all samples decreased while titratable acidity and organic acid contents increased. During storage, the pH, firmness, consistency and syneresis values, and acetaldehyde, diacetyl, and acetoin contents of the samples decreased, while titratable acidity, cohesiveness, viscosity index, water-holding capacity values, and organic acid (except pyruvic acid) and ethanol contents increased. As a result of this study, it was found that yoghurts produced under the effect of a magnetic field with an intensity of 180 μT were of higher quality in terms of physical, chemical, microbiological, and sensory criteria compared with other samples.