Frozen Storage Stability of Modified Pollock Theragra chalcogramma) Blocks Containing 15% or 30% Minced Pollock

Abstract

Pollock were removed from ice or refrigerated seawater after 2, 4 and 6 days and processed into fillet blocks or fillet blocks containing 15% or 30% minced flesh. Although all the samples were acceptable after 12 months, the addition of minced flesh and storage at -18°C affected texture and flavor. This was particularly evident for blocks containing 30% minced flesh, and results suggest the addition of minced flesh should be limited to 15%. Changes in dimethylamine and expressed thaw drip may explain the changes in sensory attributes since there were small changes in the control blocks held at -34°C. INTRODUCTIONIN 1984, domestic processors of fishery products purchased over 300 million pounds of fillet and minced blocks mainly using cod and other members of the gadoid family such as Walleye pollock, Theragru chalcogramma (Thompson, 1985). Over 99% of these blocks were imported. Part of the difficulty facing domestic production of pollock blocks is minimizing production costs to compete with imported blocks. High speed filleting and skinning machines are available but even the best machines will produce a significant number of fillets with bones, patches of skin and other defects. An alternative to the labor intensive effort of manually removing the defects from these fillets is the use of mechanical flesh separators to produce a boneless, skinless mince that could be mixed with the fillets to form a modified block. Although minced flesh deteriorates much faster during frozen storage than intact fillets (Tokunaga, 1964; Babbitt et al., 1972), Licciardello et al. (1979 found that blocks of Atlantic cod (G&us morhuu) containing up to 30% mince were not distinguishable from standard fillet blocks during 60 weeks storage at -18°C. Using pollock that had been previously frozen, Babbitt et al. (1984) demonstrated that an acceptable block can be produced using chopped fillets with 20% mince but blocks with 50% mince were not acceptable. The purpose of this study was to determine the effects of incorporating minced fresh into blocks of fillets from pollock held in ice or refrigerated seawater (RSW).