Document Type : Research Paper
aAnimal Science Research Institute of Iran
Islamic Azad University-Sari branch, Mazandaran, Iran
Department of Food Science, Sari University of Agricultural Sciences and Natural Resources, Iran
Department of seafood processing, Faculty of marine science, Tarbiat Modares University, Iran
Tuna processing by-product is estimated more than 100,000 metric tonnes annually in Iran, which could be a potential source of edible protein for human food. Hence, recovering proteins from tuna by-products is a big achievement in the seafood industry. In this work tuna protein isolates (TPI) were extracted from dark/ red meat using the isoelectric solubilization/ precipitation method. Oxidative stability, biochemical indices and characteristics of the fatty acid composition of TPI (pH 6.5) containing 16.2% protein, 1.2% fat and mixed with a blend of salt and sucrose –as a cryostabilizer- and stored 6 months at -24°C were studied. The levels of peroxide (PV), TBARS, FFA and total volatile base nitrogen (TVB-N) were significantly increased in TPI without cryostabilizers during the storage time. The results revealed that 22 fatty acids were identified in the light and dark tuna meat and TPI. The fatty acid composition of light and dark muscle of tuna and TPI containing salt and sucrose was the same. But a significant change was observed only in the TPI free from cryostabilizers during frozen storage. The results confirm inhibiting of lipid oxidation due to incorporating salt and sucrose to TPI.