4. Conclusions
This is the first report that investigated the combined effect of freezing and MAP treatments on some quality characteristics of A. foliacea (GRS) specimen during a 12-month storage period. For emphasis, the quality characteristics of this study determined proximal and gas compositions, melanosis scoring, chemical parameters of pH, TVB-N, TBA as well as FAAs. Specifically focused toward chemical-free seafood consumption, the conducted study involved vacuum-packaged-, sulphite-, 100% N2 and 50% N2 + 50% CO2-treated GRS samples. Through robust comparisons, it was shown that pH of 100% N2 and 50% N2 + 50% CO2-treated groups remained below that of SUL groups throughout storage period of this study, and somewhat so for TVB-N at only 100% N2-treated groups. The low lipid oxidation found at all treated-GRS groups although within a limited range suggests not the very best parameter to explain the lipid damage of freeze-processed samples under MAP combined treatments. By sensorial evaluation, the comparatively less melanosis scores obtained at 100% N2-treated group would appear capable of keeping the natural colour of shrimp hence, very promising replacement for SUL treatment. While individual FAAs exhibited no clear differences with storage and yet 100% N2-treated group appearing with improved individual FAAs, the total FAA of vacuum-packaged and sulphite-treated GRS samples would vary noticeably with storage although bit less at 100% N2- and 50% N2 + 50% CO2-treated groups. Overall, the combination of freezing and MAP treatments as the preservative treatment method stands great promise to influence specific characteristic qualities of GRS samples relative to the conventional preservative methods particularly sulphite-agents, the latter nowadays commonly used and increasingly associated with health risks. Further studies should be directed to apply treatments on other economically important fishery species similar to those of the present study determining other chemical and physical properties, which can incorporate among other parameters, colour and texture attributes so as to provide additional yet robust data, to facilitate further comparisons and supplement existing literature.