Vibrations as a cause of texture defects during yogurt manufacturing – Formation of vibrations and their propagation in dairy production lines

Abstract

Abstract Vibrations during the fermentation of yogurt and related milk products have recently been reported to disturb the gelation and result in quality defects such as particle formation, graininess, and syneresis. However, primary research on this topic was focused on experiments performed on a laboratory and pilot-plant scale. In this study, three large dairy factories were visited, and yogurt samples were directly taken out of various fermentation tanks, showing great differences in terms of graininess and particle content. Thereupon, vibration measurements were conducted at three industrial yogurt plants. Particularly, pumps and their influence on the vibrational excitation of the fermentation tanks were examined. The major structural and mechanical differences of these plants, such as distances between the vibration source and the tank or the types of pumps used, led to varying vibrational states at the fermentation tanks. We concluded that the vibrational excitation of each plant must be evaluated individually in order to estimate the potential for vibration-induced texture defects.