Chemical changes and visual appearance of albacore tuna as related to frozen storage

Fresh albacore tuna (Thunnus alalunga) were frozen and stored at -18 degree s C and -25 degrees C for 1 yr, Chemical and visual analyses were carried o ut at 1, 3, 6, 9 and 12 mo storage, Storage time correlated (p<0.05) with t he low loss of moisture at -18 degrees C, slight reduction of TVBN at -25 d egrees C and low increases of DMA, TMA, and TEARS at both temperatures. TMA O concentration (p=0.07), drip loss on cooking (p=0.52), peroxide value (p= 0.059), FFA concentration (p=0.33) and pH (p=0.20) did not change significa ntly with period of storage but -25 degrees C resulted in a lower productio n of DMA and FFA than -18 degrees C. Results from chemical analyses correla ted well with basic visual appearance.