A look at the function of ascorbic acid in loaf manufacture and why is is not in the Campaign's definition of Real Bread
As ascorbic acid (E300) is one commonly-used artificial additive that some bakers might ‘overlook’ when it is already in the flour they use (always read the label!), or excuse ‘because it’s only vitamin C’, we believe it deserves a closer look.
To be clear: ascorbic acid (aka E300 or l-ascorbic acid)* is an artificial additive and a loaf made using it - either added to the flour by the miller or added to the dough by the baker - is not what the Campaign calls Real Bread.
Ultimately, it is up to each of us to decide what we want to put into the food we make and the food we put into our (and in some cases our children’s) mouths.
We hope that, like all other pages on our site, this makes a contribution to the information that helps you to make choices about the food you make and eat.
In general, the known health benefits of ascorbic acid far outweigh any potential risks, though please see the note below on the lack of health benefits of ascorbic acid as used in baking.
There is evidence that ascorbic acid can be harmful in high concentration or very large does (i.e. several grams a day), but as noted above, the amounts used in baking are so low, that this is not a consideration. Please read this in conjunction with the precautionary principle we believe should be applied to all food additives.
Consuming the ascorbic acid that can be used in baking does not provide the beneficial effects of vitamin C found in, say, an orange as it is:
* Like many processing aids and other food additives, is it not destroyed (as industrial bakers sometimes like to claim about such things) in the sense that its residues remain in the loaf.
All bakers using The Real Bread Loaf Mark have signed an agreement that they will only use it for loaves baked without the use of any artificial additives or processing aids.
By law, any mill that has added ascorbic acid (E300) to its flour or baking mixes has to declare so on the label – you will find it on the ingredients, perhaps alongside other unnecessary extras, such as added enzymes…
The same applies to wrapped loaves and other pre-packed baked goods – though if deemed by the producer to be ‘processing aids’ the added enzymes would not have to appear on a loaf wrapper.
At present, bakers and retailers do not have to provide ingredients lists for unwrapped loaves. As noted in our call for an Honest Crust Act, we demand a change in law to require that they do and in the meantime urge all bakers to do so voluntarily.
Of course, we also urge all bakers and millers currently using ascorbic acid to stop doing so!
Industrial bakers categorise ascorbic acid as a flour ‘improver’ or dough conditioner. In the presence of oxygen, ascorbic acid becomes an oxidising agent and the ‘improvements’ to which it contributes include:
‘The net result of AA is to improve the ability of dough to retain gas (as seen by increased oven spring) and to yield bread with a finer (smaller average cell size) crumb cell structure. These changes also result in bread crumb that is softer to the touch yet has the resiliency to recover much of its original shape after compression. This helps to convey the impression of proved freshness to the consumer.’ Baking Problems Solved, p 55, S. Cauvain & L. Young, Woodhead Publishing (2001)
Brace yourself for a bit of food science:
‘Ascorbic acid is, of course, a reducing agent but, during dough mixing, the enzyme ascorbic acid oxidase, naturally present in flour, catalyses its conversion to its oxidising form, dehydroascorbic acid (DHAA). In a reaction catalysed by another flour enzyme, DHAA converts glutathione (GSH), a tripeptide naturally found in wheat flour, to its dimer (GSSG). GSH, but not GSSG, can form disulfide bonds – so removing GSH prevents it from disrupting the disulfide crosslinking that otherwise form between gluten proteins.’
‘It is the network of disulfide bonds formed in the gluten structure that enables the dough to retain carbon dioxide produced by the yeast.’ Vitamin C in food processing
The ascorbic acid used as a food additive can be a highly-refined and purified extract from a natural vegetable source (e.g. citrus fruit) or it can be synthesised from sugars and other carbohydrates a multi-step chemical and microbial process, e.g.
'Firstly, D-glucose is hydrogenated to D-sorbitol, followed by oxidation of the diacetone derivative of L-sorbose. The resulting diacetone-2-keto-l-gluconic acid is converted to L-ascorbic acid by heating with hydrochloric acid'
Unless the label states the source of ascorbic acid, the only way of knowing would be to ask its producer.
If you feel inclined to use a squeeze of lemon or orange juice in your dough for its ascorbic acid content, it would not fall foul of our Real Bread criteria.
Before you do, however, we do ask you to understand why and consider whether you really need to.
A UK patent for the use of ascorbic acid in baking was issued in 1936.
It was, however, only when the tide turned against the use of other supposedly ‘safe’ chemicals including potassium bromate and azodicarbonimide on health grounds that ascorbic acid became more popular amongst industrial bakers in the UK.
ASCORBIC ACID….why use it?
Is L-Ascorbate the Same As Ascorbic Acid?
The Bioavailability of Different Forms of Vitamin C
Effect of Ascorbic Acid on the Rheological Properties of Wheat Fermented Dough
Functional role of ascorbic acid in bread-making
Substitution of ascorbic acid for potassium bromide in the making of French bread
Ascorbic Acid as an Oxidant in Wheat Flour Dough. II. Rheological effects
Functional role of ascorbic acid in bread-making
Vitamin C degradation during storage of fortified foods