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Has anyone defined a defrost temperature of frozen food for pH checking?


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#1 carine

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Posted 28 July 2020 - 03:53 AM

Has anyone defined a defrost temperature (for instance; frozen food)  for pH checking? Or just do the pH check whenever product is melted?

 



#2 pHruit

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Posted 28 July 2020 - 07:53 AM

You might want to have a quick read of this recent topic on the influence of temperature on pH: https://www.ifsqn.co...ect-ph-reading/

 

Certainly I'd be looking to standardise to a specific reference temperature for your analysis.



#3 zanorias

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Posted 28 July 2020 - 04:31 PM

You might want to have a quick read of this recent topic on the influence of temperature on pH: https://www.ifsqn.co...ect-ph-reading/

 

Certainly I'd be looking to standardise to a specific reference temperature for your analysis.

Carine started that thread pHruit ;)



#4 Charles.C

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Posted 28 July 2020 - 09:33 PM

Has anyone defined a defrost temperature (for instance; frozen food)  for pH checking? Or just do the pH check whenever product is melted?

Hi carine,

 

As per previous post and just by scanning the literature, pH of frozen foods can also vary with frozen time, eg -

 

The pH of peas and of poultry meat frozen pre‐ and post‐rigor was measured during frozen storage at −10°C for up to 6 months. In peas it decreased sharply from 6.7 to as low as 6.0 during the first 3 days of storage, increased to 7.0 during the next 2‐3 weeks, decreased to 6.4 in another 3 weeks, and remained there with only small fluctuations during the rest of the storage time. Breast and leg meat of poultry resembled each other in pH changes after freezing: increases and decreases of about 0.2–0.3 unit occurred in all samples at about the same time. Meat frozen pre‐rigor differed from meat frozen post‐rigor, however, the latter increasing 0.2–0.3 pH unit during freezing, and the former changing little or decreasing slightly under these conditions. Differences in pH between samples at a given time were related to differences in initial pH.

Studies with salt solutions as similar as possible in composition to the foods tested, and with gelatin solutions, showed that pH changes in frozen foods were caused mainly by increasing concentration of food components, including proteins, in the unfrozen phase, by precipitation of salts, by interaction of proteins with ionic substances, and by enzymatic activity (e.g. lactic acid formation) during frozen storage.

https://onlinelibrar....1964.tb00408.x

 

 

for measurement pH In yr (unknown) product case, see perhaps -

 

https://www.hannains...n-products.html


Kind Regards,

 

Charles.C





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