Rigidity and Viscosity Changes of Croaker Actomyosin During Thermal Gelation


  • M. C. WU,

  • T. C. LANIER,

  • D. D. HAMANN

  • Address all correspondence to: The authors are affiliated with the Dept. of Food Science, North Carolina State Univ., Raleigh, NC 27695-7624.

  • Paper No. 9218 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, NC.

  • This work is a result of research sponsored, in part, by NOAA, Office of Sea Grant, Dept. of Commerce under Grant No. NA-83AA-D-00012 and the North Carolina Dept. of Administration. The U.S. Government is authorized to produce and distribute reprints for governmental purposes notwithstanding any copyright that may appear hereon.

  • The use of trade names in the publication does not imply endorsement by the North Carolina Agricultural Research Service, nor criticism of similar ones not mentioned.


Two types of thermal scanning rigidity monitors (TSRM) were developed which are nondestructive and capable of monitoring rigidity or viscosity changes during heating of proteins over a wide range of concentrations. Thermal transitions which occur during gelation of croaker actomyosin were studied by these TSRM devices and the Brookfield viscometer during constant rate heating (1°C/min). Gelation of actomyosin occurred only at protein concentrations above 5.5% under these conditions. In plots of rigidity versus temperature, three transitions were observed during gelation, occurring near 38°C 46°C and 60°C. At lower concentrations, only one peak was observed, occurring near 36°C. A relationship between the 36–38°C transition in rheological properties and the high temperature “setting” phenomenon of fish proteins is postulated.