Title: The effect of brine on the quality and safety of smoked Atlantic mackerel (Scomber scombrus).

Author(s): James John Banda
Type:
Final project
Year of publication:
2019
Publisher:
GRÓ-FTP
Place of publication:
Reykjavík
Number of pages:
40
Supervisors: Sigurjon Arason , Carina Fernandes , Marvin Ingi Einarsson , Jonas Baldursson
Keywords:
brine; smoked; quality; safety; Atlantic mackerel;

Abstract

The quality and safety of smoked pelagic fish products along the value chain is a complex event that required multiple analyses to define its stability. Consequently, changes in microbiological total viable count (TVC) and specific spoilage organisms (SSO) and physicochemical characteristics (total volatile base-nitrogen (TVB-N), total lipid, free fatty acids (FFA), peroxide value (PV) and thiobarbituric acid reactive substance (TBARS) of brined and unbrined smoked Atlantic mackerel (Scomber scombrus) were evaluated for 24 days period of storage. Total viable counts were significantly (p=0.002) higher in unbrined than in brined smoked S. scombrus stored at 20°C. Brined smoked S. scombrus stored at 0-4°C had lower TVC during the storage period. TVB-N levels increased with storage time, but the increase was evident in unbrined than brined samples stored at 20°C. TVB-N for brined smoked samples stored at 0-4°C below the acceptable limit for throughout the storage period. No significant differences (p>0.05) in lipid content were observed between the groups after smoking and during storage. Lipid hydrolysis and oxidation were higher in unbrined smoked samples stored at 20°C but was rather stable at 0-4°C. The shelf life of smoked S. scombrus was estimated to be 4 and 5 days for unbrined and brined samples stored at 20°C, while samples stored at 0-4°C had a shelf life of 20 days. The study shows that the use of brine in hot smoked mackerel creates the unavailability of ionically water molecules needed by micro-organisms. Low storage temperature decreases the level of hydrolysis by inhibiting enzyme activity responsible for spoilage. This has potential of achieving quality and safe value-added products along the pelagic fishery. Therefore, application of the technique in the Malawi fishery value chain cannot be over emphasized.

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