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# Protein content of cooked and raw offal

Created January 30, 2013 at 2:00 PM

I've seen on http://nutritiondata.self.com/ that the protein content of both kidney and liver (seems to go for every source) goes up when cooked. Can anyone explain how it can increase from around 20g/100g to 26g/100g just by cooking it? To me it seems like a very big difference and I can't see what should cause this (at least to that extent).

(943)

on January 30, 2013
at 05:07 PM

@greymouser I know exactly what you mean. Only thing is that I'm always thinking in absolute amounts. I now realise that the way it's in these places is with the yield taken into account - which I thought it wasn't. I completely agree with your calculations. Thanks for clarifying it and making sure I eat more liver :)

(19150)

on January 30, 2013
at 03:53 PM

@Hemming First, there is loss of macronutrients. In this case, most likely fat. Then there is loss of water. Think about it this way: some amount of raw liver X, *yields* a cooked amount of liver Y. X = Y + water loss + fat loss. X and Y *cannot* be equal unless water and fat loss is zero (which it is not in this case). In your given, it would have taken 130g of raw liver to produce 100g of cooked liver. 20/100=26/x; 20x=2600;x=2600/20;x=130.

(943)

on January 30, 2013
at 03:13 PM

@greymouser - yes, it has a different makeup in relative terms. But how can the absolute protein content increase that much just by cooking it?

(943)

on January 30, 2013
at 02:31 PM

Don't take this the wrong way. But where is that stated?

(978)

on January 30, 2013
at 02:20 PM

Hemming, the values are absolute, but they are measuring different amounts of product. It takes about 125g of raw liver to make 100g of cooked liver. (Which I now realize is a much clearer way of stating what I said above)

(19150)

on January 30, 2013
at 02:20 PM

This is the correct answer. 100g of the cooked version has a different makeup than 100g of the raw version. For dense meat specifically, the change is mainly due to loss of water then loss of fat. The change in bacon, for e.g., would be mainly due to loss of fat.

(19150)

on January 30, 2013
at 02:18 PM

This is the correct answer. 100g of the cooked version has a different makeup than 100g of the raw version.

(943)

on January 30, 2013
at 02:07 PM

The values listed should be absolute amounts as they are stated in grams.

(943)
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2

(978)

on January 30, 2013
at 02:03 PM

I think it is just that the serving size is weight at time of serving, and after cooking there is some water weight loss. Looking through it, the macro nutrients seem to increase, showing this effect, but the micro nutrients are not following it. But it is most likely that they took the data from different analyses of different pieces, and there is a lot of natural variation in micro nutrients.

No nutrition data is perfect, you can not both analyze everything you eat and eat it.

(943)

on January 30, 2013
at 02:31 PM

Don't take this the wrong way. But where is that stated?

(943)

on January 30, 2013
at 05:07 PM

@greymouser I know exactly what you mean. Only thing is that I'm always thinking in absolute amounts. I now realise that the way it's in these places is with the yield taken into account - which I thought it wasn't. I completely agree with your calculations. Thanks for clarifying it and making sure I eat more liver :)

(19150)

on January 30, 2013
at 02:20 PM

This is the correct answer. 100g of the cooked version has a different makeup than 100g of the raw version. For dense meat specifically, the change is mainly due to loss of water then loss of fat. The change in bacon, for e.g., would be mainly due to loss of fat.

(943)

on January 30, 2013
at 03:13 PM

@greymouser - yes, it has a different makeup in relative terms. But how can the absolute protein content increase that much just by cooking it?

(978)

on January 30, 2013
at 02:20 PM

Hemming, the values are absolute, but they are measuring different amounts of product. It takes about 125g of raw liver to make 100g of cooked liver. (Which I now realize is a much clearer way of stating what I said above)

(19150)

on January 30, 2013
at 02:18 PM

This is the correct answer. 100g of the cooked version has a different makeup than 100g of the raw version.

(943)

on January 30, 2013
at 02:07 PM

The values listed should be absolute amounts as they are stated in grams.

(19150)

on January 30, 2013
at 03:53 PM

@Hemming First, there is loss of macronutrients. In this case, most likely fat. Then there is loss of water. Think about it this way: some amount of raw liver X, *yields* a cooked amount of liver Y. X = Y + water loss + fat loss. X and Y *cannot* be equal unless water and fat loss is zero (which it is not in this case). In your given, it would have taken 130g of raw liver to produce 100g of cooked liver. 20/100=26/x; 20x=2600;x=2600/20;x=130.