Losses of taurine, creatine, glycine and alanine from cod (Gadus morhua L.) fillet during processing

Processing of fish generally leads to losses of water soluble compounds, and some of these may have beneficial health effects. The aim of this study was to determine the loss of taurine, creatine, free glycine and free alanine from cod during brining and cooking. Fillet pieces (n = 80) were excised from 10 cods, and divided among 8 groups subjected to different preparations: raw, brined, boiled, fried, baked, brined & boiled, brined & fried and brined & baked. The concentration of the compounds decreased during brining and true retention (TR) was calculated to be 83% and 84% for taurine and creatine, respectively. Followed by cooking, TR dropped to 69-73% for taurine, and 68-78% for creatine depending upon heat treatment. Glycine and alanine had similar losses and there were only small differences in TR between the four components. The results indicated that baking had the highest retention, followed by frying and then boiling, but the differences were not significant. Brining had no significant effect on retention of components after cooking. In addition, the experiments revealed a large variation in taurine concentration between pieces sampled from different locations of the loin. (c) 2006 Elsevier Inc. All rights reserved.