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Taking a potato as an example. If I wanted to know how much µg or % of each of it's amino acids there are in 1 gram of pure potato protein, where can I find this information?

Is there a freely accessible database online with these statistics? Or, one that contains something for each protein from which this could be derived? (and if so how?)

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  • $\begingroup$ you mention as an example a "potato" - I put a link to the USDA database that lists a number of foods and protein sources and the known nutritional info $\endgroup$ – Vance L Albaugh Dec 29 '15 at 2:15
  • $\begingroup$ Both excellent answers so far, I'm a bit short on time so I haven't figured out yet which answer is effectively best to accept, though I've been looking into both, but rest assured there will accept properly and upvote in a day or 2 max. P.S.: Should I expect much fluctuation in bio-availability of the amino acids for each protein? Or is bio-availability more of a thing to worry about for other compounds and not at all for proteins and amino acids? $\endgroup$ – Happy Dec 29 '15 at 22:34
  • $\begingroup$ The bioavailability shouldn't fluctuate much for the protein, which should be fairly constant for each of the individual amino acids - I can't comment what the bioavailability is for the nutrients other than the macro nutrients (i.e. Carbohydrates, fats, amino acids) $\endgroup$ – Vance L Albaugh Dec 30 '15 at 3:38
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There's a fantastic database available from the United States Department of Agriculture that includes almost 9,000 common foods, including their nutritional information. This database is searchable and available from the USDA Agricultural Research Service. Here is a link for the online searchable database.

Within the database you are able to search for a number of parameters; including, food composition, water content, individual amino acid content, fatty acid and total fat content, vitamins, minerals, phytonutrients, and more! One of the nice things is that you can ask it to rank the foods in order of nutrient composition. For example, ranking all the foods in the database in order of protein content or a specific amino acid (or whatever else you're interested in).

It's a great database, especially for researchers that need a database of trusted nutrient data.

USDA Database

Within the database you can search by nutrient or by food, whichever you are curious about. For example, as you mention in the question, I entered potato and in the second screen shot below you can see the listing of all the nutrients in the potato. These are listed as % weight per 100g of potatoes - with or without the skin.

Potato screenshot

To get to the amino acid content breakdown, click on Full Report (All Nutrients) at the top.

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  • $\begingroup$ Which question to upvote between you and Samuel is a brain breaker. The original question was per gram protein, I assume you changed my question to account for foods that contain additional lose amino acids. However I effectively needed per gram pure protein from the food rather than per g of food. Anyhow I've upvoted your question. $\endgroup$ – Happy Dec 30 '15 at 19:45
  • $\begingroup$ @Happy the USDA database gives you both the total amount of protein and the total amounts of amino acids (as well as all the other nutrients) - you can divide one by the other to get amino acid per gram of protein. Now I think I'm confused by what you're saying... ? $\endgroup$ – Vance L Albaugh Dec 30 '15 at 19:54
  • $\begingroup$ Yeah in Samuel's case an additional calculation seems to be also needed so I think I'll just settle on your answer as accepted one. $\endgroup$ – Happy Dec 30 '15 at 20:02
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Go to WolframAlpha and enter 1g potato in the input field:

enter image description here

Then scroll down in the results to Protein and amino acids and click the more button in the top right hand corner to get the following list of amino acids with their compositional values for one gram potato:

enter image description here

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you need to know the protein sequence to be able to do this.

Paste the protein sequence into this tool and press 'Compute Parameters'. This will give the percentage amino acid composition of the protein.

http://web.expasy.org/protparam/

Otherwise if you mean 'generic protein from potato' then as a quick google reveals this http://journals.cambridge.org/download.php?file=%2FBJN%2FBJN12_02%2FS0007114558000271a.pdf&code=829c6412f21656bf0e528452fc6608c7

I am not sure there is a database of amino acid composition of foods

EDIT

Actually I found this resource, might warrant further inspection

http://www.fao.org/docrep/005/AC854T/AC854T00.htm

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  • $\begingroup$ Good answer, I've upvoted, sadly for example for almonds the amino-acids are expressed only with A: mg/g total nitrogen, which I don't understand how to interpret as it differs wildly from B: mg/100 g food. So I don't have usable data for almonds. Oh and thank you for the cambridge article, interesting to consult it in comparison to the database. $\endgroup$ – Happy Dec 30 '15 at 19:10

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