title: Thermal stability of fish natural actomyosin affects reactivity to cross-linking by microbial and fish transglutaminases.
abstract: Natural actomyosin (NAM) from Pacific whiting (PW) showed thermal transition temperatures by circular dichroism at 31.8 and 43.1°C, which were lower than those of threadfin bream (TB) NAM, 35.0 and 49.3°C. Endothermic transitions of PW-NAM by differential scanning calorimetry were at 31.8, 42.1 and 75.3°C, compared to 36.1, 50.9 and 78.4°C for TB-NAM. Based on surface hydrophobicity, α-helical content, and solubility, PW-NAM unfolded to a greater extent than did TB-NAM when incubated at 25°C for 4h and 40°C for 2h, suggesting its lower thermal stability. Transglutaminase generally catalyzed more extensive cross-linking of PW-myosin heavy chain (MHC) than TB-MHC, and the MHC cross-linking mediated by microbial transglutaminase (MTG) was greater than by fish transglutaminase (FTG). Textural properties of PW-NAM gels increased approximately 3.6-6.1-fold and 1.3-1.5-fold in the presence of MTG and FTG, respectively.
authors.affiliation: School of Food Technology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
authors.forename: Bung-Orn
authors.initials: BO
authors.lastname: Hemung
authors.affiliation: Food, Nutrition and Health Program, Faculty of Land and Food Systems, The University of British Columbia, 2205 East Mall, Vancouver, British Columbia, Canada.
authors.forename: Eunice C Y
authors.initials: EC
authors.lastname: Li-Chan
authors.affiliation: School of Food Technology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand. Electronic address: jirawat@sut.ac.th.
authors.forename: Jirawat
authors.initials: J
authors.lastname: Yongsawatdigul
keywords: Natural actomyosin; Pacific whiting; Thermal stability; Threadfin bream; Transglutaminase