Abstract
ABSTRACTThe conformational changes of natural actomyosins prepared from fresh and freeze-thaw tilapia (Oreochromis niloticus) in the presence of Ca2+ or Mg2+ were investigated. The Ca2+-activated adenosine triphosphatase (Ca2+-ATPase) activities of actomyosins extracted from fresh and freeze-thaw fish were comparable (p > 0.05). The denaturation temperatures (Td) of actomyosins extracted from fresh fish were lower than those from freeze-thaw counterparts (p < 0.05). The addition of Ca2+ or Mg2+ reduced the Td of actomyosins. Ca2+ and Mg2+ enhanced protein aggregation at ≥ 40°C (p < 0.05). Based on the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) pattern, the myosin heavy chain (MHC) and actin bands tended to form large aggregates to a greater extent in the presence of 100mM Ca2+ or Mg2+. Ca2+ and Mg2+enhanced disulfide linkages and hydrophobic interactions among actomyosin molecules. The onset temperature of elastic modulus (G′) of both actomyosins was shifted to lower temperature as 100mM of Ca2+ or Mg2+ was added. Mg2+ at 20mM increased the breaking force of washed tilapia mince at 40°C. Our results revealed that the intrinsic properties of actomyosins extracted from fresh and frozen fish were distinct, and divalent ions Ca2+ or Mg2+ affected their gelation differently.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
