application of ultrasonic spectroscopy to the study of the gelation of milk components
Corredig, M. | Alexander, M. | Dagleish, D.G.
Measurements of the changes in ultrasonic properties of gelling dairy systems have been made. In all of the cases studied (renneting milk, acidified milk and heat-gelling whey proteins) the ultrasound was able to define different stages of the reactions which can be identified with changes in the constituent gelling particles. Formation of a gel in itself caused very small changes in the ultrasonic velocity and attenuation parameters in acidified milk, because of the other changes (changes in the structures of the casein micelles) that occurred in the system before the gelation process itself. Gelation was more clearly seen in heated whey proteins and renneting milk. During renneting, two stages could be clearly identified in the aggregation process. In this case also the effects of rennet on the micelle could be clearly seen at the start of the reaction. Although changes were seen in all systems, it was difficult to attribute the changes in ultrasonic parameters to specific molecular or conformational effects in the proteins or protein particles.Show more [+] Less [-]