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The Influence of Salting Procedures on the Characteristics of Heavy Salted Cod

Thorainsdottir, Kristin LU (2010)
Abstract
The production of heavy salted cod (bacalao) has changed from being a single-step process salting to a multistep

procedure. The aim of this study was to gain a deeper understanding of water retention and yields of heavy

salted cod as influenced by salting procedures. The effects of different pre-salting methods (injection and

brining, brining only, and pickling) were compared to a single kench salting step. The products were evaluated at

different stages of the process: after pre-salting, dry salting, storage and rehydration, with regard to changes in

yields, chemical content and salt-induced changes in muscle proteins and microstructure.

Injection was significantly different from other... (More)
The production of heavy salted cod (bacalao) has changed from being a single-step process salting to a multistep

procedure. The aim of this study was to gain a deeper understanding of water retention and yields of heavy

salted cod as influenced by salting procedures. The effects of different pre-salting methods (injection and

brining, brining only, and pickling) were compared to a single kench salting step. The products were evaluated at

different stages of the process: after pre-salting, dry salting, storage and rehydration, with regard to changes in

yields, chemical content and salt-induced changes in muscle proteins and microstructure.

Injection was significantly different from other methods in increasing weight yields through brining, dry salting

and rehydration. Salt concentrations of the brine did not influence the weight yields of dry-salted and rehydrated

products. However, salt concentrations >20% had negative effects on the colour and commercial quality of the

salted products. Addition of phosphates increased weight yield of salted but not of rehydrated products. Effects

on quality varied between trials; both negative and positive effects were observed.

Strong salting-out effects on proteins were seen due to high salt contents in the salted products regardless of the

procedures applied. The effects of salting procedures on yields and quality of heavy salted cod products were

related to the pathway of solubilisation, denaturation and aggregation of proteins in the muscle. Myosin was less

aggregated when injection was applied during pre-salting. A greater degree of protein aggregation correlated

with higher initial salt concentrations and dehydration during the first days of salting, which was obtained with

brining, pickling and kench salting. In addition, these methods resulted in stronger enzymatic degradation of

proteins, shown as an increase in lower molecular weight subunits.

The connective tissue in the muscle was believed to play an important role in water retention of the muscle.

Microstructural analysis of the dry-salted fillets showed that the intercellular spaces in injected and brined fillets

were increased compared to only brining. However, the cross-sectional area of the fish fibres was similar in both

groups.

Based on this, the main reason for higher weight yields of injected products after salting and rehydration were

believed to result from irreversible effects on the connective tissue in the muscle and better retention of myosin

structure, thereby better water-holding. The drawback of the wet-salting methods (brining and injection) was that

the yield of nitrogenous compounds was lower for injected and brine-salted fillets. However, the main changes

were due to higher losses of non-protein nitrogen, which is more likely to influence the organoleptic properties

of the products than the weight yields. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Utviklingschef Lauritzsen, Kristin, Norske Sjömatbedrifters Landförening, Trondheim, Norge
organization
publishing date
type
Thesis
publication status
published
subject
keywords
microstructure, protein, water holding capacity, water, yield, Salting, protein denaturation, cod
pages
251 pages
publisher
Department of Food Technology, Engineering and Nutrition, Lund University
defense location
Lecture hall C, Kemicentrum, Getingevägen 60, Lund University Faculty of Engineering
defense date
2010-02-19 13:00
ISBN
978-91-978122-1-4
language
English
LU publication?
yes
id
0aa2c979-2ca9-43ab-89db-75a2c954d02d (old id 1530344)
date added to LUP
2010-01-22 14:17:41
date last changed
2016-09-19 08:45:07
@misc{0aa2c979-2ca9-43ab-89db-75a2c954d02d,
  abstract     = {The production of heavy salted cod (bacalao) has changed from being a single-step process salting to a multistep<br/><br>
procedure. The aim of this study was to gain a deeper understanding of water retention and yields of heavy<br/><br>
salted cod as influenced by salting procedures. The effects of different pre-salting methods (injection and<br/><br>
brining, brining only, and pickling) were compared to a single kench salting step. The products were evaluated at<br/><br>
different stages of the process: after pre-salting, dry salting, storage and rehydration, with regard to changes in<br/><br>
yields, chemical content and salt-induced changes in muscle proteins and microstructure.<br/><br>
Injection was significantly different from other methods in increasing weight yields through brining, dry salting<br/><br>
and rehydration. Salt concentrations of the brine did not influence the weight yields of dry-salted and rehydrated<br/><br>
products. However, salt concentrations &gt;20% had negative effects on the colour and commercial quality of the<br/><br>
salted products. Addition of phosphates increased weight yield of salted but not of rehydrated products. Effects<br/><br>
on quality varied between trials; both negative and positive effects were observed.<br/><br>
Strong salting-out effects on proteins were seen due to high salt contents in the salted products regardless of the<br/><br>
procedures applied. The effects of salting procedures on yields and quality of heavy salted cod products were<br/><br>
related to the pathway of solubilisation, denaturation and aggregation of proteins in the muscle. Myosin was less<br/><br>
aggregated when injection was applied during pre-salting. A greater degree of protein aggregation correlated<br/><br>
with higher initial salt concentrations and dehydration during the first days of salting, which was obtained with<br/><br>
brining, pickling and kench salting. In addition, these methods resulted in stronger enzymatic degradation of<br/><br>
proteins, shown as an increase in lower molecular weight subunits.<br/><br>
The connective tissue in the muscle was believed to play an important role in water retention of the muscle.<br/><br>
Microstructural analysis of the dry-salted fillets showed that the intercellular spaces in injected and brined fillets<br/><br>
were increased compared to only brining. However, the cross-sectional area of the fish fibres was similar in both<br/><br>
groups.<br/><br>
Based on this, the main reason for higher weight yields of injected products after salting and rehydration were<br/><br>
believed to result from irreversible effects on the connective tissue in the muscle and better retention of myosin<br/><br>
structure, thereby better water-holding. The drawback of the wet-salting methods (brining and injection) was that<br/><br>
the yield of nitrogenous compounds was lower for injected and brine-salted fillets. However, the main changes<br/><br>
were due to higher losses of non-protein nitrogen, which is more likely to influence the organoleptic properties<br/><br>
of the products than the weight yields.},
  author       = {Thorainsdottir, Kristin},
  isbn         = {978-91-978122-1-4},
  keyword      = {microstructure,protein,water holding capacity,water,yield,Salting,protein denaturation,cod},
  language     = {eng},
  pages        = {251},
  publisher    = {ARRAY(0xa206db0)},
  title        = {The Influence of Salting Procedures on the Characteristics of Heavy Salted Cod},
  year         = {2010},
}