[M-BLAH]

Hey,
I'm a baker. Recently, I've had to work at increasing the alkalinity of one of my cake products. To do so, I have to increase the sodium bicarbonate (which is a part of the leavening/baking powder). Sodium hexametaphosphate is a common 'food' ingredient to use with sodium bicarbonate to keep the acid/alkali ratios in balance. However, I really need to know the hexametaphosphate's neutralizing value so I can assure the batter will be balanced well. The pH of hexametaphosphate ranges from 6.0 - 7.5.
Any one able to help me at all??
Cheers,
M.

[Arkcon]

I don't know what scale you're working at, but if you're doing it professionally, I'm going to assume its moderately large.  So off to Chemical Engineering sub-forum this goes.

This is a tough question on a few levels, even if it seems deceptively simple:

Briefly, its easy to calculate the pH of a mixture of an acid and base.  We'll need the pKa's of the acid and base (those are easy to look up,) and your starting pH and target.  That is deceptively simple, because I don't recognize your acid, and sodium bicarbonate has multiple pKa's.

I'm left wondering, how much sodium bicarbonate you can add, before the cake become over leavened and texture suffers.  I'm also wondering about the pH effect of all other components.  Maybe this problem is best addressed experimentally.

[M-BLAH]

Hello, and thank you very much for your reply.

I am, by no means, an expert in this field at all. I am simply trying to get as much understanding of the whole 'pH' and 'pKa' concept, enough to get this nightmarish cake formula right.

The pH value of the entire cake batter should hover just over 7.0 - and no greater than 7.4. The problem I'm currently facing, is that, all of the ingredients (including a perfectly balanced and adequate amount baking powder) bring the entire solution to about 6.7 (which falls just under the ideal level). I have tried hundreds of experiments. With the majority of them, I have played with increasing the sodium bicarbonate, little by little, to increase the pH. I have also tried keeping the sodium bicarbonate at the same levels, and decreasing the acidulants slightly (sodium aluminium phosphate and sodium acid pyrophosphate). However, when too much of sodium bicarbonate is 'left' in the batter, it can do some pretty harmful things to a cake/muffin (porous exterior, rough crumb, metallic flavours). Hence, the sodium hexametaphosphate theory.

I have seen several other recipes of the same product that use SHMP. Without it being an 'acidulant' in baking as such, I believe it is included in the batter possibly to neutralize any excess amounts of sodium bicarb whilst retaining a higher pH (SHMP has a pH of around 5.8 - 7.3). It does react with the sodium bicarb, but very minimally. Therefore, I would 'assume' it has a higher pKa?

I'm not sure whether this theory stands a fact at all, hence my question here in this forum. Does what I'm explaining make any sense at all?

My regards.

[Furanone]

I can't help with your question about sodium hexametaphosphate, but just an idea to throw out at you....

Another common food acidulant is sodium acid sulfate, which is said to have the blandest flavour for acids (no typical sourness). It has a pKa of 1.99 so I'm assuming is much more acidic than sodium hexametaphosphate, which means you could use much less of it in your recipes to reach the desired pH. Plus sodium hexametaphosphate may have some degradation products with sodium bicarbonate.

http://en.wikipedia.org/wiki/Sodium_bisulfate

Also with your problem of only achieving a pH of 6.7 when 7.0-7.4 is the desired pH, maybe use sodium carbonate instead (Na2CO3) instead of sodium bicarbonate (NaHCO3). You will have to experiment with the recipe, but it is a much stronger pH increaser since it has two sodium instead of a sodium and a hydrogen (ie. A proton = acid). Again, with sodium carbonate you can add much less of it (between approx. 50-70% of sodium bicarbonate levels) to achieve higher pHs so you won't have to worry about that baking soda off-flavour.

http://en.wikipedia.org/wiki/Sodium_carbonate

[Furanone]

After thinking about this a little bit more, I think the purpose of the sodium hexametaphosphate may be as a slow release acid, which means sodium acid sulfate in this case would not perform as well since a stronger acid (would lower pH too fast). In baking as well in many food fermentations (sourdough & yeast-leavened breads, yogurt, cheese, etc.) the rate of acid development is very important. In the case of baked products, acids react with the sodium bicarbonate or sodium carbonate to creates carbon dioxide as a byproduct and this is what rises the bread/cake, etc. If too much CO2 is formed too fast then it all escapes and cannot be trapped in time by the gluten matrix, and thus it does not rise as well and air cell size will be small. In fermentations if acid is produced to fast in yogurt or cheese then you will not get a nice thick gel or curds that bind water, but aggregated milk proteins that expel water and sediment to the bottom (try adding vinegar or lemon juice to milk in 1:1 ratio and see for yourself).

So back to your formulation: I would recommend then using your regular recipe with sodium bicarbonate and sodium hexametaphosphate to where you obtain pH 6.7, then sprinkle in the slightest amount of sodium carbonate to adjust the pH up to 7.0-7.4 as desired. So the perfect recipe is the one that has the right amount of gluten to form the matrix and trap the evolved CO2, the right amount of Carbonates so all will react to form CO2 with minimal remaining to leave a baking soda taste and the effects on texture you mention, and the right acid to react slow enough as the dough/batter is baked to gently rise the loaf/cake to the desired fluffiness & air-cell size. For super fluffy breads, some places will add in pure gluten (to up to 20% gluten) since hard wheat flour typically has about 14-16% gluten protein (rest mostly starch) while soft wheat flour (cake & pastry flour) has about 8-10% gluten protein. All-purpose Flour is typically a blend of Hard and Soft Wheat flours so a gluten content of about 10-13%.

Another slow release acid, that is often used to simulate the action of bacteria in producing acids during fermentation is glucono-delta-lactone (E575). As more GDL turns to gluconic acid (glucose sugar that has one acid group) in small quantities and as that is consumed but the NaHCO3/Na2CO3 to create CO2, the equilibrium is shifted so the GDL will form more gluconic acid. Maybe give this a try if you have some time to experiment. SALP and SAPP, you already mention, are also commonly used slow release acids used in leavening.

http://en.wikipedia.org/wiki/Glucono_delta-lactone

http://www.jungbunzlauer.com/fileadmin/content/_PDF/GdL_-_A_natural_way_of_leavening_Oct08.pdf

This second link shows a good chart comparing the different leavening agents as to rate of CO2 evolution. Another benefit of GDL is it won't contribute to the sodium content of your baked goods like all other leavening agents.

[billnotgatez]

@Furanone
Is washing soda (sodium carbonate) (Na₂CO₃) regularly used in food?
https://en.wikipedia.org/wiki/Sodium_carbonate

@MichaelY
I am trying to follow the thread and I am still wondering are you trying to make your batter more acid or more base. Also, are you adding the Sodium hexametaphosphate to change the pH or is it part of the original recipe'.
https://en.wikipedia.org/wiki/Sodium_hexametaphosphate

@anyone
Since the cooking process changes the makeup of the product, is the pH of the batter important as the resulting product. For instance, I thought the cooking process assisted in the release of the Carbon dioxide of the Sodium bicarbonate (along with acids in the batter).
https://en.wikipedia.org/wiki/Sodium_bicarbonate

[Furanone]

@Furanone
Is washing soda (sodium carbonate) (Na₂CO₃) regularly used in food?
https://en.wikipedia.org/wiki/Sodium_carbonate

It is not used nearly as much as sodium bicarbonate since it is far more potent in increasing pH and this will make the food undesirable to taste, but it is allowed. Most foods are in the acidic to neutral range. Only foods I can think of that are naturally alkaline are egg whites, pretzels, and some tortillas.

http://www.food-info.net/uk/e/e500.htm

@anyone
Since the cooking process changes the makeup of the product, is the pH of the batter important as the resulting product. For instance, I thought the cooking process assisted in the release of the Carbon dioxide of the Sodium bicarbonate (along with acids in the batter).
https://en.wikipedia.org/wiki/Sodium_bicarbonate

Yes I bring this up in some detail in the second post above.

[M-BLAH]

Hi and thanks.
I've taken all that has been posted into consideration. The product that we are trying to formulate is a muffin batter, of which is deposited into bake-stable trays and blast frozen. The product will be baked from frozen and in it's tray.
We require a long baking time. The raising agents we are working with are SALP (sodium aluminium phosphate, acidic), SAPP 28 (sodium acid pyrophosphate) and sodium bicarbonate. The SHMP (hexametaphospahte) is functioning purely as a pH adjuster, as all 'major' ingredients vary substantially in pH levels through different batches of manufacturing.
We have tried using excessive amounts of the sodium bicarbonate (to achieve a higher pH), and have also tried incorporating a food grade sodium carbonate for the same purpose. The alkalinity levels were successful, however, the non-reactive left over bicarbonate left a very undesirable (and much expected) after taste in the baked product.
SHMP has a lower pH (between 4.5 and 6.5), therefore we have only just concluded that we simply cannot achieve a high pH using it.
A few things we want to try, and would like your suggestions on, are:
- Using potassium pyrophosphate (a higher alkali) together with SALP and sodium bicarbonate, relying purely on the SALP and bicarbonate for 'lift' and the potassium to balance the pH.
OR
- Use a SALP, basic, together with the SALP, acidic, SAPP and sodium bicarbonate, adjusting the ratios of SALP acidic and basic to obtain the correct level of pH.
The reason why we hesitate to drift from using these numbers (450, 500 and 541), is because there are currently some competitors products on the market with the same 'frozen and unbaked' concept, and their formula consists of these particular numbers and works efficiently, producing a substantial product.
I hope I have made sense of it all, it's difficult trying to explain what you 'technically' want, but not having the background of chemistry and/or chemistry know-how. And comments and suggestions will be much appreciated.
M

[Furanone]

It would really help if you could describe what the behaviour of the muffins throughout baking is  what the final product is like (ie, not rising enough, rising too much, texture issues, off-flavor) and what baking behaviour & final product you desire is (ie. slow rising, small air-cell size, etc.). I realize first freezing then baking over a longer time period presents some unique challenges.