Studies on the Mechanism of Thaw Rigor in Carp.

Thaw-rigor is often found in frozen meat of bigeye tuna Thunnus obesus. Excessive amounts of drip loss and stiffness greatly lower the commercial value of tuna meat. In order to prevent thaw-rigor in meat stored at -60°C postcapture, we adapted a temperature shift technique that stores the meat at -7°C for 1 day or -10°C for 7 days before thawing. Biochemical changes in muscle of bigeye tuna before and after the temperature shift to -7 or -10°C were characterized. Contents of ATP, NAD ? , glycogen, and creatine phosphate decreased after the temperature shift. NAD ? levels decreased faster than ATP levels and were highly correlated with the rigor index. Thaw-rigor occurred in muscle containing NAD ? at 1 lmol/g and ATP at 7 lmol/g. On the other hand, the meat color of tuna during frozen storage changed to brown depending on the storage temperature and reflected the rate of metmyoglobin (met-Mb) formation. MetMb formation increase was dependent on the decrease in NADH levels during the frozen storage. A temperature shift technique with storage at -7°C for 1 day or -10°C for 7 days before thawing prevented thaw-rigor and met-Mb formation.

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“…release from the SR was suggested to cause the increased ATP consumption and the acceleration of thaw-rigor [14]. NAD ?…”

Section: Discussionmentioning

confidence: 99%

Prevention of thaw-rigor during frozen storage of bigeye tuna Thunnus obesus and meat quality evaluation

et al. 2011

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“…Because of the central role in muscle contraction, structure and function of this enzyme has been extensively studied in mammals (Inesi et al 1990). In fish, activity measurements of the Ca2+-ATPase have been performed on purified SR from trout (de Toledo et al 1995;Chini et al 1993), carp (Ma et al 1992;Ushio et al 1989) and plaice ). Studies of membrane bound enzymes often use highly purified materials.…”

Section: Introductionmentioning

confidence: 99%

SARCOPLASMIC RETICULUM Ca²⁺-ATPase ACTIVITY IN COD (GADUS MORHUA) MUSCLE MEASURED IN CRUDE HOMOGENATES

Godiksen

Jessen

2001

J Food Biochemistry

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An assay for sarcoplasmic reticulum Ca2+‐ATPase in an unfractionated homogenate from cod(Gadus morhua) muscle has been established. Specificity of the assay was demonstrated by the Ca2+ dependence of the enzyme and the effect of a specific inhibitor, thapsigargin. Stimulation and inhibition of enzyme activity was observed at low and high Ca2+ concentration, respectively. Half the maximal activity was obtained at 0.2 μM free calcium and no activity could be detected above 20 mM free Ca2+. Thapsigargin inhibited 92% of enzyme activity. Sarcoplasmic reticulum Ca2+‐ATPase showed maximal activity around pH 7 and 25C. A nonlinear Arrhenius plot was found with pronounced changes in the slope in the temperature interval 6–15C. The activation energies obtained from the approximately linear parts above 15C and below 6C were 25 kJ mot−1 and 172 kJ mol−1, respectively.

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“…The reason for accelerated ATP breakdown in frozen ®sh at temperatures just below 0°C is probably an elevated level of Ca 2 in the cytosol caused by leakage from sarcoplasmatic reticulum due to freezing-induced membrane damages. 21 In the present study the accelerated glycolysis at these temperatures was not measured directly as degradation of glycogen but indicated by the results in Fig 5 where ATP was found to be synthesised at a signi®cant rate at À7°C (or lower). The increase in ATP content can only be explained by ATP synthesis from glycogen and/or creatine phosphate.…”

Section: Discussionmentioning

confidence: 57%

Synthesis and degradation of adenosine triphosphate in cod ( Gadus morhua ) at subzero temperatures

Cappeln¹,

Nielsen

Jessen

1999

J Sci Food Agric

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This study has demonstrated that the extraction step is very important when analysing ATP and its degradation products. An important factor is whether the sample is fresh, frozen or thawed when homogenised since thawing of the sample will lead to rapid loss of ATP. During frozen storage it was found that ATP in cod (Gadus morhua) was stable at −40 °C in small samples for at least 12 weeks. At −20 °C it was found that ATP content increases initially and thereafter falls. It was demonstrated that degradation of ATP in small samples occurs faster at 0 °C than at −2 and −5 °C. Furthermore, it was found that in whole cod ATP could be synthesised at a significant rate at −7 °C. © 1999 Society of Chemical Industry

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Studies on the Mechanism of Thaw Rigor in Carp.

Cited by 14 publications

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Prevention of thaw-rigor during frozen storage of bigeye tuna Thunnus obesus and meat quality evaluation

Prevention of thaw-rigor during frozen storage of bigeye tuna Thunnus obesus and meat quality evaluation

SARCOPLASMIC RETICULUM Ca²⁺-ATPase ACTIVITY IN COD (GADUS MORHUA) MUSCLE MEASURED IN CRUDE HOMOGENATES

Synthesis and degradation of adenosine triphosphate in cod ( Gadus morhua ) at subzero temperatures

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Studies on the Mechanism of Thaw Rigor in Carp.

Cited by 14 publications

References 0 publications

Prevention of thaw-rigor during frozen storage of bigeye tuna Thunnus obesus and meat quality evaluation

Prevention of thaw-rigor during frozen storage of bigeye tuna Thunnus obesus and meat quality evaluation

SARCOPLASMIC RETICULUM Ca2+-ATPase ACTIVITY IN COD (GADUS MORHUA) MUSCLE MEASURED IN CRUDE HOMOGENATES

Synthesis and degradation of adenosine triphosphate in cod ( Gadus morhua ) at subzero temperatures

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SARCOPLASMIC RETICULUM Ca²⁺-ATPase ACTIVITY IN COD (GADUS MORHUA) MUSCLE MEASURED IN CRUDE HOMOGENATES