A.R Shaviklo - aAnimal Science Research Institute of Iran
H Mozafari - Islamic Azad University-Sari branch, Mazandaran, Iran
A Motamedzadegan - Department of Food Science, Sari University of Agricultural Sciences and Natural Resources, Iran
N Damavandi-Kamali - Department of seafood processing, Faculty of marine science, Tarbiat Modares University, Iran

Tuna processing by-product is estimated at more than ۱۰۰,۰۰۰ metric tonnes annually in Iran, which could be a potential source of edible protein in 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 ۶.۵) containing ۱۶.۲% protein, ۱.۲% fat and mixed with a blend of salt and sucrose – as a cryostabilizer - and stored ۶ months at -۲۴°C were studied. The levels of peroxide (PV), TBARS, FFA and total volatile basic nitrogen (TVB-N) were significantly increased in TPI without cryostabilizers during the storage time. The results revealed that ۲۲ 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. However a significant change was observed only in the TPI free from cryostabilizers during frozen storage. The results confirm inhibiting of lipid oxidation due to the incorporation of salt and sucrose to TPI.

Tuna processing by-product, Protein isolates, Frozen storage, Fatty acid profile, Cryostabilizer