Electronic versions of two articles are now available in the Journal of Food Engineering and Food Chemistry (see links below).
Both sectors are related to salted fish processing. The first article discusses the effect of different brine concentrations on the weight changes of cod muscles and the uptake of salt during pickling. The second article discusses the effect of different salting methods on protein deformation and how the results can be linked to variability in product utilization.
The articles are the result of doctoral projects that have been done for the most part at Matís, ie. the project of Minh Van Nguyen who is studying at the University of Iceland and the project of Kristín Anna Þórarinsdóttir who has graduated from Lund University Sweden.
The projects were funded by AVS (R042-05), Rannís (R051364005) and the Nordic Innovation Center Fund (04252). In addition, the United Nations University-Fisheries Training Program has funded Minh Van Nguyen for the program and Kristín Anna Þórarinsdóttir's Nordic Marine Academy (NMA) program.
The main information about the articles, as well as an excerpt, can be found below. The names of the authors who work at Matís are underlined. For further information, please contact Kristín Anna Þórarinsdóttir, Director of Matís (e-mail: kristin.anna.thorarinsdottir (at) matis.is).
Minh Van Nguyen, Sigurjon Arason, Kristin Anna Thorarinsdottir, Gudjon Thorkelsson, Agusta Gudmundsdottir. 2010. Influence of salt concentration on the salting kinetics of cod loin (Gadus morhua) during brine salting. Journal of Food Engineering, Volume 100, Issue 2, 225-231
Abstract
The influence of different salt concentrations of 6%, 15%, 18% and 24% (w / w) on mass transfer of water and salt during brine salting of cod loins was studied. An increase in salt concentration accelerated water exudation and salt diffusion in the cod loins. Weight gain of the cod loins increased with decreasing salt concentration and the cod loins in the 6% brine had the highest process yield. The salting kinetic parameter values for total and water weight changes decreased with increasing salt concentration. Inversely, higher salting kinetic parameter values for salt weight changes were observed for higher brine concentrations. The samples brined at 18% and 24% had identical effective diffusion coefficients and the highest effective diffusion value was found in the cod loins brined at 15%.
doi: 10.1016 / j.foodchem.2010.09.109
Kristin Anna Thorarinsdottir, Sigurjon Arason, Sjofn Sigurgisladottir, Thora Valsdottir, Eva Tornberg. 2011. Effects of different pre-salting methods on protein aggregation during heavy salting of cod fillets. Food Chemistry, Volume 124, Issue 1, Pages 7-14.
Abstract
The use of injection and brining as the first step in heavy salting of cod increases weight yields of the products through both salting and rehydration, compared to other pre-salting methods, like brining only and pickling. This is interesting since salt content of the muscle exceeds 20% NaCl, in all procedures. Therefore, the dissimilarities in yield were presumed to depend on the degree of protein denaturation and aggregation as influenced by the different salting procedures. This hypothesis was studied and confirmed with the aid of SDS – PAGE and DSC-analysis. Higher water retention of injected products was explained by stronger salting-in effects on proteins during pre-salting, reducing aggregation of muscle proteins during the dry salting step. The degree of protein aggregation during salting increased in the following order with regard to the different pre-salting methods: injection and brining <brining <pickling. These effects were still observed after rehydration. Furthermore, differences in denaturation / aggregation were assigned to both myosin and collagen.
