ULTRASONIC STUDY OF GELATION PROCESS IN EGG-WHITE PROTEINS

Ultrasonic velocity and absorption measurements were made in ovalbumin , conalbumin and ovomucoid which are protein constituents of egg white , at 3 MHz over the temperature range of 10 to 95 degrees C using the pulse-echo-overlap method. The gelation process induced by heat was st udied based on the changes in velocity and absorption. The gelation te mperatures of ovalbumin and conalbumin were 70 degrees C and 50 degree s C, respectively. However the gelation of ovomucoid did not occur und er the range of temperatures investigated. The changes in velocity and absorption due to gelation were observed as a function of lime at agi ng temperatures ranging from 50 to 95 degrees C for conalbumin, and fr om 70 to 95 degrees C for ovalbumin. The experimental results showed t hat the changes were prominent at 55 degrees C in conalbumin and at 75 degrees C in ovalbumin. Hysteresis phenomena were also observed by va rying the aging temperature. The phenomena are associated with the mem orizing effect of the network structure of protein in gel. It was demo nstrated that the ultrasonic technique was useful for monitoring the g elation process.