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Last week, I ordered wheat gluten to make seitan. I received some powder and attempted a recipe, which mixes 100g of water with 100g of gluten to form a sticky dough. However in my case, I only got a thick fluid. Even after adding 50g more gluten, I was unable to form pieces from the result. Almost all recipes for seitan use a one-to-one mixture (or even more water), so I have the assumption, that the powder is actually not gluten. Of course I did contact the company and they sent a replacement. However, the powder seems to be exactly the same.

Now I am wondering whether its possible to properly check whether the powder is gluten or not. There are some test kits online, but they are very costly, probably because they are intended to find even small traces of gluten for allergen tests. Maybe there is a cheap option or even something I could attempt at home with easy-to-get chemicals?

I am aware of the biuret test to check for proteins, but the company does sell lots of supplements and powdered "super foods", so I guess a protein test would be positive for half their stock.

Any other ideas?

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    $\begingroup$ Try a different supplier, presumably. I can't imagine it's very expensive or difficult to obtain? Probably simpler than checking gluten content. You could however check whether it is starch: en.wikipedia.org/wiki/Iodine%E2%80%93starch_test $\endgroup$
    – Buck Thorn
    Feb 14 at 10:14
  • $\begingroup$ Sure, but I am still interested in finding out whether this stuff is gluten at all, or something entirely different. The latter would also be quite interesting regarding food safety. $\endgroup$
    – Alduno
    Feb 14 at 10:38
  • $\begingroup$ Also compare similar question at reddit.com/r/chemistry/comments/1aqj46f/… $\endgroup$
    – sjb-2812
    Feb 14 at 11:20
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    $\begingroup$ @Alduno As for the seitan as such, cooking.stackexchange.com could be an audience suitable, because there is a tag seitan (as are gluten-free and vital-wheat-gluten, too). $\endgroup$
    – Buttonwood
    Feb 14 at 11:41
  • $\begingroup$ You may want to add details about what kind of budget you have. What you have done (a dissolution test) is about the simplest test you can run, and fairly effective for detecting some forms of adulteration, for instance in honey. $\endgroup$
    – Buck Thorn
    Feb 15 at 11:31

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I think you should approach any engineering or chemistry related institutions nearby your location, if they have facility of "mass spectrometry" then they can compare the sample against pure gluten to tell how much of gluten is there. This is the most effective way I know.

There's a another way which is to use Mark–Houwink equation, to determine the molecular weight of polymer (ie your sample) and compare it against molecular weight of gluten.You can easily get procedure 'to determine the molecular weight of a high molecular weight polymer by viscosity measurement'. It requires only a Oswald Viscometer(easily available) and a stop watch. I had used this method to determine molecular weight of polystyrene and results were satisfactory. The only problem is that I am not sure if you can get the data required(value of a constant a for solution of gluten in some solvent) to plug in MHS equation to get molecular weight. I you can then this is the most practical way to solve the problem.

If you can't do both of these, then comparing results of preliminary tests like checking solubility in different solvents or flame test (is flame sooty or not) for given sample against pure gluten may work, but it's not an fool proof way and there's a possibility that you get incorrect result.

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  • $\begingroup$ Not bad, but gluten is a wild mixture of (mostly) proteins, varying between sources. $\endgroup$
    – Karl
    Feb 15 at 20:19

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