Thermal stability of myofibrillar protein from Indian major carps

The characteristics and stability of natural actomyosin (NAM) from rohu ( Labeo rohita ), catla ( Catla catla ) and mrigal ( Cirrhinus mrigala ) were investigated. The total extractable actomyosin (AM) was higher (7.60 mg ml −1 ) in the case of rohu compared with that from catla and mrigal (5 mg ml −1 ). Although the specific AM ATPase activity was similar (0.43–0.5 µmol P min −1 mg P −1 ) among the three species, the total ATPase activity was lower in mrigal (25 µmol g −1 meat) compared with the other species (37 µmol g −1 meat). The inactivation rate constants ( k d ) of AM Ca ATPase activity showed differences in the stabilities of actomyosin among these fish, the actomyosin from catla being least stable. The NAM from these species was stable up to 20 °C at pH 7.0. Catla AM became unstable at 30 °C, while rohu and mrigal AM could withstand up to 45 °C. The thermal denaturation with respect to solubility, turbidity, ATPase activity, sulphhydryl group and surface hydrophobicity showed noticeable changes at around these temperatures. Copyright © 2004 Society of Chemical Industry