Thermal Denaturation and Aggregation of Actomyosin from Atlantic Croaker

Abstract

The denaturation of croaker actomyosin was studied with respect to the important role of coagulation and gelation phenomena in the manufacture of gel-type meat and fish products. Measurements of turbidity (Aeoo), viscosity, calcium ATPase activity, total sulfhydryl groups and protein coagulation of croaker actomyosin solutions during heating at a constant temperature increase of l"C/min 16 vealed no loss of enzymic activity nor evidence of protein aggregation prior to reaching a temperature of 37-4O"C, at which point the protein coagulated with corresponding loss of ATPase activity and sulfhydryl groups and an increase in turbidity. The degree of protein coagulation was highly dependent on the' protein concentration. An observed increase in the apparent viscosity over the 30-35°C temperature range was postulated to result from interaction of protein molecules due to noncovalent forces.

Some physico-chemical, functional and rheological properties of actomyosin from green mussel (Perna viridis)

“…The stability at 40 and 50°C could arise from increased hydration of actomyosin molecule. Some researchers have attributed similar observation of viscosity increase during heating to the entanglement of partially unfolded actomyosin molecule (Liu, Lin, & Lanier, 1982;Nakayama, Niwa, Hamada, & Shin, 1979). The thermal stability is highly intrinsic phenomenon and depends on conformation of proteins (Tanford, 1970).…”

Use of Konjac glucomannan as additive to reinforce the gels from low-quality squid surimi

“…This abrupt loss of G 0 and G 00 upon heating at over 55°C, could be caused by intensive degradation of myofibrillar proteins. This in turn could be caused by a number of different factors, such as precipitation/coagulation of myofibrillar proteins (Liu et al, 1982) and/or kinetic constraints in myosin gel formation (Wu et al, 1991); moreover, when the gelling mechanism is virtually complete, subsequent heating leads to a reduction in hydrogen bonds, and hence to reduced rigidity (Damodaran and Paraf, 1997). Gómez-Guillén et al (1997) used a different technique, Thermal Scanning Rigidity Monitor (TSRM), to analyze rigidity in gelation of minced D. gigas muscle.…”

Aislamiento y caracterización parcial de miosina del manto de calamar gigante (Dosidicus gigas)

“…El aumento detectado a partir de los~40-45°C, es similar a lo reportado en corvina (Micropogonias undulatus) y conejo (M. longissimus) (Liu, Lin, & Lanier, 1982;Samejima, Ishioroshi, Conclusiones Bajo las condiciones de este estudio se establece que la miosina aislada del manto de calamar gigante posee una menor cantidad de grupos sulfhidrilos totales y reactivos, al ser comparada con lo reportado en la literatura para otras especies marinas. Asimismo, esta proteína fue sensible a la concentración de sal, presentando mayor solubilidad, mayor actividad enzimática, así como una mayor hidrofobicidad de superficie a mayor concentración de KCl, indicando que la proteína tiende a desplegarse por la acción de los iones presentes en la sal sobre los aminoácidos cargados presentes en las moléculas.…”