The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Gluten - Protein ...

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flournwater's picture
flournwater

Gluten - Protein ...

I see the terms gluten and protein used somewhat interchangably in some of the threads on this forum and I'm wondering if my interpretation is correct.


As I understand it, the greater amount of protein in a given type of flour the higher it's gluten content will be.  So a 10% protein flour is lower in gluten than a 12% protein flour?  Did I miss sometehing?


Also, is the percentage of protein listed on the nutrutional outline on the flour package a percentage by weight?   I suspect it is, but uncertainty haunts me still.

suave's picture
suave

There're two types of proteins in flour - glutenin and gliadin, when water is introduced they combine forming gluten, so in a sense it is the same thing.  Nutritional table doesn't give percentage of protein, just weight per serving, and the number is a very innacurate measure of protein content - try it and you will see that for a 30 g. serving 12, 13 and 14 will all round to 4 g.

rayel's picture
rayel

But High protein doesn't mean high gluten necessarily, as in Durum wheat? Yeah I'm confused. Re nutrition info, I asked someone at King Arthur Flour about how to read that percentage, and he agreed that it was ambiguous, and that if I did the math I would be more confused. (easy for me) Does harder wheat mean higher protein?


Ray

SourFlour's picture
SourFlour

Gluten is a type of protein, but not all protein is gluten.  For wheat flour, I believe the majority of the protein is gluten, but there might be small percentages of other types of protein.


Therefore, even though there might not be an exact correlation (13% protein might mean 12% gluten), in general they go together.


Hope this helps.


Danny - Sour Flour
http://www.sourflour.org

flournwater's picture
flournwater

OK then, if the nutritional label says one serving = 30 grams, and there are 3 grams of protein in one serving, the gluten may not be 100% of the protein and therefore the flour is not necessarily 10% protein.  However, if I'm looking for a flour that boasts 11 - 12% protein and a second brand/type of flour lists 30 grams per serving with 4 grams of protein in each serving (about 12%) then I'm pretty well assured that I've got a flour that will serve bread making purposes better than the 3 grams per serving variety?

suave's picture
suave

Protein content has no direct relation to suitability for bread baking. 

flourgirl51's picture
flourgirl51

Protein of the wheat definitely has a lot to do with bread baking. Most commercial flour mills mix high and low protein wheats when they do their milling.

suave's picture
suave

Meaning that they are lowering gluten-forming ability of flour on purpose to make it better for bread baking?

flournwater's picture
flournwater

Well, suave, I thought so too.  But KA seems to think it does.  See why it's so confusng?  Check out "thanks to all" below ...

suave's picture
suave

Yet all the most expensive flours they sell have low protein content.  But why, why, why do they say it is their 11.7% flour is "ideal for your favorite French and Italian loaves".  If more protein means better bread why say 11.5% flour is "flour of choice for baguettes"? Because that's what they say.

AndyM's picture
AndyM

...better bread.  Sometimes, when the protein content gets too high, you can end up with reults that are not what you are looking for.  This is particularly true in crumb texture - in many french and italian styles of bread, a light, somewhat fluffy interior is prized.  This texture is most easily achieved with a moderate amount of gluten.  If your flour has too much gluten in it, you can end up with a rubbery, tough texture inside the loaf. 

Mini Oven's picture
Mini Oven

Each kind of wheat has it's own character.  Each kind of grain as well.  Labeled protein can be a guide but the characteristics of the flour type must be considered. 


I've been in situations where I've not had a choice in flour.  I worked with it, tweaked my recipes to deal with it and have changed my methods to come out with an acceptable loaf to my family's particular taste.   It has been a great learning experience.  It is absolutely amazing to find out how many variables can be changed to get a different result with just one kind of flour.  One kind of flour can produce pizza, cinn rolls, hard rolls, soft rolls, flat breads, pancakes, crepes, free standing loaves, sourdough, pretzels, bagels, cakes, dumplings and noodles if one takes the time to understand the limits of that particular flour and how to manipulate it.  Speck sheets are a great help, having a variety of flours can be practical (and confusing) but can't replace hands on cooking, baking and aquired experience or shared experience.   Just buy some flour and work with it, learn from it.


Mini

flournwater's picture
flournwater

Thanks, all.  I've been using Mini's recommended approach for about a year now and it has worked fairly well.  What got me started with this question was just that I've been reading so many posts recently that insist that a flour with less than 11% - 12% protein is a poor choice for bread making.  Then I read one earlier this week that indicated "bread" flour on a package didn't mean anything; nor did "All Purpose" flour, because KA allegedly labels a flour "All Purpose" and it supposedly has enough protein to work well as a bread flour and that the labels of other mills that market "bread" flour really aren't high enough in protein to justify the label.  Then I read on KA web site that their "bread" flour " ... has a protein content of 12.7% - a full point higher than other national brands – helping even whole-grain and mechanically kneaded yeast breads rise high. And King Arthur Unbleached Bread Flour is the top-selling unbleached bread flour in the nation."  Then, for their Sir Lancelot Unbleached "high gluten" bread flour, they say "This is the highest-gluten flour (14.2% protein) available on the retail market today."  That's how I got confused.


So I think I'll just go back to experimenting with different flour types and not be concerned with protein content.  Otherwise I'll drive myself nuts.....


 

AndyM's picture
AndyM

My understanding is that, as mentioned above, the protein percentage is important as an indicator of gluten content.  But it is only an indicator.  This is because of the two different proteins that must work together to form gluten.  If these two proteins are not in the ideal balance with each other, then you could get a high-protein flour that is of poor bread-making quality.  Perhaps it would have too much glutenin and not enough gliadin, leading to doughs that are too tight, and not stretchy enough.  Or, you could get the opposite effect with an overabundance of gliadin, leading to doughs that stretch nicely but don't hold their shape well.  So the protein content is a proxy for the qualities we look for in ideal bread-making flour. The result is that one 11.7% flour might make very different bread than a different 11.7% flour. 


This issue of balance between proteins is one reason why flours from other wheat-related grains, such as spelt, have different baking properties.  In many cases, spelt flours have higher protein percentages than wheat flours, but they tend to have more gliadin relative to glutenin, meaning that they make more extensible, less strong doughs.  Not that this makes spelt bad for bread-making - I've had some spectacular spelt breads.  The dough just needs to be handled differently.


So, how can you tell what kind of bread any given flour will make?  You could try to get the technical specs from the miller - most large-scale producers will do tests on each lot of flour, and if you work hard enough, you could probably get them to share that information with you.  But it's a lot of work, and things like farinographs are not all that easy to read.  I use Mimi's approach of trying out a flour and learning from it.  Again, most large-scale producers of flour go to great lengths to produce flour that is consistent from one batch to the next, so if you find a flour you like, you're fairly safe to stick with it.  But even then, there will be minor variations from lot to lot (in my experience, this variability is more pronounced with the small-scale, organic producers whose flour I tend to use).  I enjoy these variations, as they keep me on my toes, ensuring that I am responding to the dough itself, rather than relying on any pre-set ideas about how the process "should" work.

flournwater's picture
flournwater

Thank you. Andy.  That's a wonderful explanation and it's really all I needed to know.  Hang on to a file copy of that paragraph so you can post it at some point in the future when another confused novice bread baker raises the same question.


Better yet, include it when you write your book on the subject.

dghdctr's picture
dghdctr

If you search for Todd Bramble's comments (here at TFL) about flour and its proteins, you might find it an interesting read.  I think it's still to be found here.  Todd is a flour tech at King Arthur.


And Google Books has a few sample pages of a book called Food Processing:Principle and Applications that provides specifics as well:


http://books.google.com/books?id=QDpi_6VnhegC&lpg=PA188&ots=1k4dl-ZLVN&dq=wheat%20%22water%20soluble%20proteins%22&pg=PA189#v=onepage&q=wheat%20%22water%20soluble%20proteins%22&f=false


Anyway, when we're talking about wheat or other cereal grains, there are basically two categories of protein present -- proteins that are soluble in water (like albumens and globulins, for instance) and those that are insoluble (like glutenin and gliadin).  Enzymes like protease and amylase are considered proteins as well -- I'm not sure which type they are, but I'm leaning toward soluble.


I've seen figures for around 75-80% of the proteins in wheat -- on average -- being insoluble glutenin and gliadin.  I'm not certain what the specific percentages are for each of the soluble ones, but it seems they would amount to 20-25%.


Perhaps SteveB -- who has a doctorate in chemistry, I think  -- could provide a more specific, coma-inducing answer.  WARNING: do not read what SteveB may  tell us about protein bonds unless you are near your bed and can devote at least 8 hours for sleep.


--Dan DiMuzio

hansjoakim's picture
hansjoakim

Quote:
Perhaps SteveB -- who has a doctorate in chemistry, I think -- could provide a more specific, coma-inducing answer. WARNING: do not read what SteveB may tell us about protein bonds unless you are near your bed and can devote at least 8 hours for sleep.

I always read Steve's posts with great interest, and I think we're extremely fortunate to have such an accomplished baker share his expertize with us.

dghdctr's picture
dghdctr

He and I tease each other like that occasionally.  I apologize if you felt I was honestly disrespectful to him, or that it was misplaced levity.  I know him well, and I agree that his contributions are valuable.

SteveB's picture
SteveB

Hans, thank you so much for your comment.  I am electronically blushing!  :"-)           


Without knowing of my friendship with Dan, I can understand how his gentle ribbing might have been interpreted as an insult.  If the worst that can be said about my posts is that they are boring, then they have improved dramatically!  Heck, I even put myself to sleep sometimes while writing them... zzzz....  


 


SteveB


www.breadcetera.com