MRI Archives - Matís

The effects of pre ‐ salting methods on salt and water distribution of heavily salted cod, as analyzed by 1H and 23Na MRI, 23Na NMR, low ‐ field NMR and physicochemical analysis and 23Na MRI, 23Na NMR, low range NMR and physical property measurements

Post author By admin
Post date 31/03/2014

Published:

31/03/2014

Authors:

María Guðjónsdóttir, Ásbjörn Jónsson, Magnea G. Karlsdóttir, Sigurjón Arason, Amidou Traoré

Supported by:

AVS Fisheries Research Fund (R45-12)

Contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

The effects of pre ‐ salting methods on salt and water distribution of heavily salted cod, as analyzed by ¹H and ²³On MRI, ²³Na NMR, low ‐ field NMR and physicochemical analysis / Impact of pre-salinization methods on salt and water distribution of fully salted cod products, analyzed by ¹H and ²³On MRI, ²³Na NMR, low range NMR and physical property measurements

The effect of different pre-salting methods (injection salting with or without phosphate, pickling and brine salting) on the water and salt distribution in dry salted cod fillets (Gadus morhua) was investigated by proton and sodium NMR and MRI methods. In addition, the salt and water content were assessed, as well as water resistance. The results indicated that spraying with salt and phosphate resulted in a more uneven water distribution in the fillets compared to other pre-salting methods. On the other hand, brine-salted fillets had the least homogeneity in salt distribution. Fillets from all sample groups had stains with unsaturated brine, but such stains can increase the risk of microbial damage in the fillets during storage. The effect of the pre-salting methods remains throughout the processing process on both fully salted and dried products. As homogeneous water and salt distribution were not achieved with the pre-salting methods studied, further research into the salting process is needed.

The effect of different pre ‐ salting methods (brine injection with salt with / without polyphosphates, brining and pickling) on the water and salt distribution in dry salted Atlantic cod (Gadus morhua) fillets was studied with proton and sodium NMR and MRI methods, supported by physicochemical analysis of salt and water content as well as water holding capacity. The study indicated that double head brine injection with salt and phosphates lead to the least heterogeneous water distribution, while pickle salting had the least heterogeneous salt distribution. Fillets from all treatments contained spots with unsaturated brine, increasing the risk of microbial denaturation of the fillets during storage. Effects from the pre ‐ salting treatments remained throughout the processing line to both dry salted and dried products. Since a homogeneous water and salt distribution was not achieved with the studied pre-salting methods, further optimizations of the salting process, including the pre-salting and dry salting steps, must be made in the future.

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Water distribution in commercial Icelandic heavily salted Atlantic cod (Gadus morhua) / Water distribution in fully salted cod

Post author By admin
Post date 31/03/2014

Published:

31/03/2014

Authors:

María Guðjónsdóttir, Ásbjörn Jónsson, Magnea G. Karlsdóttir, Sigurjón Arason, Amidou Traoré

Supported by:

AVS Fisheries Research Fund (R45-12)

Water distribution in commercial Icelandic heavily salted Atlantic cod (Gadus morhua) / Water distribution in fully salted cod

Water distribution in a variety of products from Icelandic fully salted cod was analyzed using proton magnetic resonance imaging methods. The products were both flat and filleted, in addition to which they varied in terms of fishing methods, processing before or after death hardening, pre-salting methods (injection salting with / without phosphate, brine and brine salting) as well as the choice of injection machines. All products had an even water distribution, but the homogeneity depended on processing methods. Double injection of salt, as well as simple injection into a muscle before death, led to needle punctures in the muscle, which were even detectable after "kench" salting. Analysis of relaxation time indicated that brine salting led to high muscle protein depletion compared to other pre-salting methods. Injection salting led to a salt-inducing swelling in the muscle, and this effect was maintained even after the "kench" salting step. Multivariate analysis of all variables showed that the MR methods are powerful methods for evaluating the processing properties of products, as well as for maximizing processing methods.

The water distribution of various commercially available Icelandic heavily salted Atlantic cod) products were analyzed with proton magnetic resonance methods. The products varied in choice of catching method, in pre ‐ or post ‐ rigor processing, flattening or filleting cut, and pre ‐ salting technique (brine injection with salt with / without polyphosphates, brining and pickling) and choice of brine injection instruments. All products had a heterogeneous water distribution, but the level of heterogeneity was dependent on the handling during processing. Double brine injection and brine injection into pre ‐ rigor muscle lead to needle traces in the muscle, even after kench salting. Relaxation time analysis indicated that pickle salting leads to the highest degree of protein denaturation in the muscle of the analyzed pre ‐ salting methods. Brine injection lead to salt ‐ induced swelling, which effect remained after the kench salting step. The multi ‐ parametric analysis performed indicated how powerful the MR methods are for process and product characterization and optimization.