Title: Quality changes in salted, rehydrated and dry salted cod (Gadus morhua) products

Author(s): David Bamwirire
Final project
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Kenching; spectrophotometer; inject-salting; enzyme activity; protein; water activity and microbial load.


The quality and yield of traditionally salted fish in Uganda is still unsatisfactory. The purpose of this study was to investigate the changes that occur during various salting methods. This was done through evaluating the effects of salting methods on selected variables used as indicators of quality in salted, rehydrated and dried salted cod (Gadus morhua). Generally salting and drying significantly decreased the yield in all methods, affecting mainly kenching and brining. Rehydration, however, enhanced the yield in all methods, with kenching attaining the highest. Salt content increased in all methods (19.5-21.4%) but the methods showed decreasing moisture and water activity. The kench products had significantly lower water activity than the rest of the methods during salting and drying. The salt content in rehydrated products reduced to low levels (4.6-6.2%) but attained a high water activity (0.95-0.97). There was a general increase in the microbial load in salted and rehydrated products. A general increase in the protein content in all the methods was observed during the first days but reduced in the advanced stages of drying. In the rehydrated products, the highest total protein content (salt free) was noted in the brine and kench salting methods compared to the inject-salt methods. Results also showed a very low activity of the proteolytic enzymes (trypsin and chymotrypsin) in all products. In general, the overall differences between the methods were minimal; indications were that the yields in the modern methods (inject-salted) were higher than in the traditional methods of kenching and brining.

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