Chemical Changes and Visual Appearance of Albacore Tuna as Related to Frozen Storage

Abstract

ABSTRACT Fresh albacore tuna ( Thunnus alalunga ) were frozen and stored at –18°C and –25°C for 1 yr. Chemical and visual analyses were carried out at 1, 3, 6, 9 and 12 mo storage. Storage time correlated (P<0.05) with the low loss of moisture at –18°C, slight reduction of TVBN at –25°C and low increases of DMA, TMA, and TBARS at both temperatures. TMAO 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 significantly with period of storage but −25°C resulted in a lower production of DMA and FFA than −18°C. Results from chemical analyses correlated well with basic visual appearance.