Danang,
These answer was given a few months ago:
Some work has been done at the SU:
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2621.1975.tb12550.x
https://catalog.library.jhu.edu/ipac20/ipac.jsp?session=X21221442MT78.125608&profile=general&uri=link=3100007~!8310938~!3100001~!3100002&aspect=subtab22&menu=search&ri=1&source=~!horizon&term=Blueing+processed+crab+meat+%3A+II.+Identification+of+some+factors+involved+in+the+blue+discoloration+of+canned+crab+meat+%28Callinectes+sapidus%29+%2F&index=ALTITLE
http://www.marlees.com/crabs_101.html
In 2006 Peter Howgate gave this answer in this same comunity
The book Chemistry and Biochemistry of Marine Food Products. R.E.
Martin, G.J. Flick, C.E. Hebard, D.R. Ward, eds,Westport, Co. USA: Avi
Publishing Co., Inc. has a chapter, Chap 20, pp 423-428, by Babbitt,
'Blueing discoloration of Dungeness crabmeat.' which discusses the
chemistry of the process. You ask specifically how to stop it and I copy
the last 3 paragraphs from the chapter.
"How then can the blueing discoloration be prevented? Industry, by trial
and error, has developed several practices to reduce the incidence of
blueing. Only crabs that are alive and in good condition are processed.
Crabs that have been held in a cooler (1?-3?C) even for up to 4 days are
edible if properly cooked. However, the chances of blueing occurring in
the cooked crab are greatly increased, particularly if the cooking times
and temperatures are not adequate to inactivate the phenolases.
Certainly, care must be taken to properly cook the crab, since
underprocessing will result in blueing.
Molting is a factor in the blueing reaction, since the phenolic
compounds are involved in the formation of the new shell
(sclerotization) of the crab. So, during times of molting, extra care
must be used in handling and processing crab to prevent blueing.
If the crabmeat is to be thermal-processed, the cooking time and
temperatures of the raw crab are not as critical. However, as soon as
the crab is cooked, the meat from the shell must be removed and
thermal-processed. Regardless of how long the live crab are cooked, any
delay in thermal pricessing the crabmeat will result in a higher
incidence of blueing. Using frozen crab sections to produce canned
crabmeat will also increase the risk of blueing. Whole crab or crab
sections should be thoroughly cooked before freezing to reduce the risk
of blueing. Finally, avoid any contact of copper or iron with the crab
since these metals can greatly intensify the blueing discoloration."
Peter Howgate
Gerald Schlesinger
*BLUMOS S.A.
*Exposición 1316
Santiago-Chile
Fono: 56-2-9473343
Fax: 56-2-9473399
dan yoga escribió:
> Dear all,
>
> I have just start working as QC on pasteurized crabs. There are
> something that I need to ask to all of you. Sometimes I found some
> blueing meat in raw material that going to be canned. Why it is can be
> happend and is it have a high risk for healthy or only on economical
> risk? beside that what is the risk of used sodium pyrophosphate as
> retain color in pasteurized can if there is an overdosis to human
> healthy?
> Thanks for the answer before.
>
> Best Regards,
> danang
>
>
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