Why bread in commercial bakeries looks beautifully browned and stays fluffy: Additives and preservatives

E524 (sodium hydroxide) is used to clear drains. This additive is used to coat certain breads to get a shiny brown surface. PHOTO: THE STAR
E524 (sodium hydroxide) is used to clear drains. This additive is used to coat certain breads to get a shiny brown surface. PHOTO: THE STAR

(THE STAR/ANN) - The food you see in supermarkets and commercial outlets may not actually be food.

Brown bread or stone-ground bread, for example, has no formal definition in EU law and can be made with white flour with added colourings plus optionally some cheap roughage material.

The brown colour can be introduced, for example, by coffee or perhaps E150a (caramel) or some of its derivatives, E150b (caustic sulphite caramel), E150c (ammonia caramel) and E150d (sulphite ammonia caramel).

So if you want proper brown bread, make sure it is actually made with wholegrain or wholemeal flour. Note that chemicals can also be applied to the exterior of foods.

In the EU, it is common to have the skins of fruits sprayed with combinations of imazalil, orthophenylphenate, propiconazole or thiabendazole – these are anti-fungal agents used to delay the rotting of fruit.

In large quantities, they have been linked to cancers and deaths in test mammals – but in the amounts sprayed on fruits, they should not be problematic for healthy humans.

Just make sure fruits are washed thoroughly before handling or eating them, especially those which are often ingested with the skin on, such as grapes, pears, peaches and apples.


We have briefly covered some of the psychological aspects of commercial food production, including presentation and preservation of food items so that they appear wholesome, edible - and remain generally safe to eat.

The following now deals mainly with how textures of processed food are maintained consistently and why such foods feel good in the mouth.

Not all the engineering is about adjusting base food ingredients; for example, blending fats and other ingredients to achieve the optimal Calorific Density that is most appealing to humans – there is also an arsenal of natural and synthetic chemical compounds which can be added to the ingredients to considerably enhance the textures of even heavily-processed foods.

It is regrettable but not uncommon to find that there are actually more food additives than the supposedly main food ingredient – which may even be missing.

An example is a label for “liquid apple” from a major US supplier.

The ingredient list is a chemical bath of just about everything unrelated to apples (except for a cursory mention of some natural flavour, but not natural juice), and it bizarrely also has a warning that some unlisted milk ingredients are also included in a supposedly apple drink.

When I was younger and trying my hand at baking, it soon became obvious that it is impossible to achieve the consistent, homogenous distribution of tiny air bubbles found in commercial bread loaves.

Every homemade batch was different, with irregular bubbles and varying textures no matter how long the dough was proofed.

My own breads also harden pretty quickly after baking but that is because I did not use the preservatives mentioned earlier.

Visiting artisan bakeries in France and Germany later made me feel better because the handmade loaves there also had irregular bubble patterns and were closer in texture to my own breads, except of course, the professional breads tasted much better.

This sort of leads to questions about other packaged foods in general: how do creams remain creamy, why do tinned vegetables not turn into mush, why do colours of canned food remain bright and attractive, how come powdered foods/flours do not clump together, how do sauces/jams/relishes retain their consistency years after they have been stuffed into bottles, how do large bakeries dependably churn out exactly the same cakes, biscuits and breads every day – and so on.

And the answer, not unexpectedly by now, is often due to the chemistry of additives. So let us see how all this works.

Thickeners, gelling agents, emulsifiers and stabilisers

The E4xx category of food additives are mostly emulsifiers, stabilisers and humectants (compounds that help moisture retention), though a few artificial sweeteners are also included.

These E4xx compounds mainly add texture to foods – they ensure that soups, gravies and creams retain a creamy uniformity, baked goods do not get lumpy, ingredients bind or gel properly, meats taste “juicy”, and sauces and jams stay consistently thick.

There are several thickeners, gelling agents and stabilisers commonly used in food processing – they are used to improve the textures of food ingredients and a lot of them are derived from natural sources.

Examples are E406 (agar) and E441 (gelatin) which are often found in processed meats, ice creams, cakes and gum sweets; E410 (locust bean or carob gum) is used in ice lollies, cordials, dressings, essences, also as a chocolate substitute; E412 (guar gum, or guaran) and E415 (xanthan gum) are found in sauces, ice creams, cheese spreads, cake mixes, et cetera.

The E415 is also commonly used as a binding agent for gluten-free baked goods. Pectin or E440a is used to thicken sauces and jams in particular. And so on.

An interesting texture-improvement additive is E407 (carrageen), partly because it has been recently banned by the US-based National Organic Standards Board (NOSB) as an additive in organic foods. This compound is derived from red seaweed (originally harvested around Carrigan Head, Ireland) and has been consumed for centuries.

This is a curious compound because large concentrations have been known to kill test rodents but toxicity in humans is hard to establish, despite unverified claims of intestinal irritation and damage.

However, there is a degraded version of carrageen called poligeenan which may be the actual culprit compound – and poligeenan is not a permitted additive.

Why emulsifiers?

Emulsifiers are added when it is necessary to keep oils and water-based ingredients consistently blended so they do not separate. They work because the emulsifying molecules have both hydrophilic and hydrophobic attributes – hence the hydrophilic end will bind with water and the hydrophobic end will bind with anything that is not water, like oil, resulting in a smooth, homogenous distribution of the bound ingredients.

This normally improves texture and taste significantly. Examples of emulsions are mayonnaise and ice creams. There are not many naturally-extracted emulsifiers – mainly E407 (carrageen, though mostly used as a thickener), E413 (acacia gum or gum Arabic) and E322 (lecithin, which is also an antioxidant) spring to mind.

E472a-f (esters of mono- and di-glycerides of fatty acids derived using organic acids, for examples, acetic, citric, lactic or tartaric) are somewhere in the middle between natural and synthetic emulsifiers.

Many emulsifiers are therefore synthetic compounds and the most fascinating ones are possibly esters. Simply defined, esters in food are compounds derived from an acid reacting with fatty acids – they are formed by the replacement of hydroxyl (oxygen-hydrogen, -OH) groups of molecules with alkoxy (oxygen-bond, -O-) groups of molecules.

As an aside, other kinds of esters are also derived from organic acids reacting with various alcohols – and these esters are used in the perfumery business or even as food aromas for they can smell very pleasant; for example, pentyl ethanoate smells of ripe pears and octyl ethanoate has the scent of bananas.

It smells great, but …

But being fascinating and nice-smelling does not necessarily mean that synthetic esters are wholly safe to ingest, especially in large quantities. The additives in the range E432 (polysorbate 20 or polyoxyethylene 20 sorbitan monolaurate or Tween 20) to E436 (polysorbate 65 or Tween 65) may be the most well-known examples, being derivatives of sorbitol (a low-calorie sweetener extracted from glucose) reacted with a well-known mammalian carcinogen called ethylene oxide in a process called ethoxylation.

The number after polysorbate indicates the number of parts of ethylene oxide present – but the issues are compounded by the possible presence of another potent mammalian carcinogen called dioxane as a by-product of ethoxylation.

If you are curious about E432-E436, then check your bathroom because these chemicals are also used as surfactants in beauty creams, shampoos and soaps. Although polysorbates in food have been evaluated and deemed safe in 2015 by the European Food Safety Authority in the quantities permitted, the possibility of contamination by ethylene oxide and dioxane may not have been fully considered.

A little personal comment about E471 (mono-and di-glycerides of fatty acids) might be in order now. Although trans-fats are banned in the EU, it is still a little unclear if mono- and di-glycerides derived from trans-fats are included in the ban as they are not fats (triglycerides) in the classic sense. In any case, many countries will probably still be using trans-fats to produce E471 as it is the cheapest way to manufacture a widely-used emulsifier.

If you like fibre

If you are fond of foods with fibre, then you are possibly in luck because the food industry introduces a lot of fibre as a filler and binder in processed foods such as cakes, breads, muffins, scrambled eggs, mash potato powders, grated cheeses, et cetera.

The main fibre used, primarily because of its low cost, is E460 (cellulose) which is made from wood pulp.

In fact, despite the image that added food fibre is derived from oats, bran, wholegrains, et cetera, the reality is that most of it actually comes from specially processed wood.

Different characteristics of fibre (eg. textures, binding, dispersal qualities, et cetera) can also be readily synthesised resulting in additives such as E461 (methyl cellulose), E462 (ethyl cellulose), E463 (hydroxypropyl cellulose), E464 (hydroxypropyl methyl cellulose), E465 (ethyl methyl cellulose), E466 (carboxy methyl cellulose), E468 (crosslinked sodium carboxymethyl cellulose) and E469 (enzymatically hydrolysed carboxymethyl cellulose).

The main side effect noted from consuming cellulose-based additives is flatulence, simply because cellulose is indigestible by humans.

Other food improvers

We now start to get to the more oddball sections of E-numbers. For example, the next group of E5xx numbers deals generally with compounds also used to improve textures and retention of food colours, including coagulants and treatments for flours used in baking, such as anti-caking and browning agents. Some components of the E5xx groups are also considered as mineral supplements in addition to its function as an additive – though this is possibly not wholly by intent.

An immediately peculiar additive is E524 (sodium hydroxide) as this is the same chemical used to clear blocked drains.

This additive is used to coat the external surfaces of certain breads and causes them to develop a shiny brown surface during baking. If you are curious how this works, it is because strong alkalis degrade the proton linkages in starch polysaccharides, thereby loosening the molecular structure of the polymers and causing them to react more easily with sugars under dry heat – then they turn brown due to the Maillard reaction.

Due to its acute toxicity and difficulty in obtaining food-quality sodium hydroxide, very often E500 (sodium carbonate, sodium bicarbonate, sodium sesquicarbonate) is now used instead. E500 is a major component of baking powder – it is also used to curdle milk for certain cheeses.

Another interesting additive is E516 (gypsum or calcium sulphate) which is commonly used to coagulate tofu though it is also used as a bleaching and flour treatment agent. This natural compound is sometimes present in health drinks and infant milk formulas as a calcium supplement.

A synthetic additive is E518 (magnesium sulphate, also known as Epsom salts) – it is used to maintain the structure of canned vegetables, and also utilised in cheese, sweets and flours. If consumed in excess, E518 is a pretty strong laxative.
E579 (ferrous gluconate) is a very water-soluble black crystal, and often included as an iron supplement – its main food use is as a food dye, particularly for dark olives.

A somewhat intriguing additive is E541 (sodium aluminium phosphate) for this synthetic compound has both acidic and alkaline variants. The acidic variant of E541 is heat-activated and used commonly in baking as it combines with E500 to produce carbon dioxide but only at baking temperatures – this makes the dough easier to manage and also obviates the need to proof the dough. The alkaline variant of E541 is used to emulsify processed cheeses.

Not such a beautiful mind

As an aside, I confess to not being a great fan of ingesting compounds containing aluminium, primarily because the metal has been known to impair the absorption of calcium by the body, potentially leading to bone tissue diseases.

Despite some studies suggesting a link between aluminium and neurodegenerative diseases like Alzheimer’s, the verdict is still inconclusive on this matter.

Regardless, it has been established for some years that aluminium is definitely neurotoxic – and humans accumulate the metal in their brains over time.

How aluminium may or may not trigger neurological degeneration could be related to its interaction with calcium and magnesium ions in the brain – but this is all somewhat theoretical at present and subject to research.

When more scientifically-conclusive details are known about the effects of ingesting aluminium compounds, it would be very interesting, not least because of the pervasiveness of aluminium in our lives.

In any case, aluminium is not in any way a critical mineral for survival and hence I would personally be wary of ingesting any foods with these E-numbers: E520 (aluminium sulphate), E521 (aluminium sodium sulphate), E522 (aluminium potassium sulphate), E523 (aluminium ammonium sulphate), E541, E554 (sodium aluminium silicate), E555 (potassium aluminium silicate), E556 (aluminium calcium silicate), E559 (aluminium silicate, or kaolin) and E1452 (starch aluminium octenyl succinate).

In short, I shy away from ingesting any compound where aluminium is named as part of their chemical structure. E541 has been discussed above and the rest of these additives are mostly anti-caking agents or firming agents for processed fruits and vegetables. Oddly, there is another additive, E173 (aluminium) which I would also avoid as it is just powdered aluminium in a pure form.

In case you are now wondering about the ubiquitous aluminium tins used to hold fizzy drinks and certain foods, the contents of these tins are protected from the aluminium by an epoxy resin barrier, usually derived from bisphenol A (BPA) or bisphenol S (BPS).

There are too many E5xx additives to list and comment on – but E512 (stannous chloride) caught my eye as there are very few tin-based compounds used in food, being mainly used for the external cans that hold food. E512 is used to retain the colour of tinned or bottled vegetables, mainly asparagus.

In large amounts, this compound is known to damage DNA in human white blood cells – it is also a hazardous skin and eye irritant and can kill test mammals administered with excessive doses of the compound.

Another curious additive is E553b (talc) – yes, the same stuff you used to put on babies’ bottoms. The exterior use of talc-based powders for infants is now banned in the EU due to the potential of asbestos contamination – but it seems it is possible to use pure talc in food as a separation agent for rice, powdered foods (and medicines), cheese slices, sausage skins, table salt, et cetera.

Again, please note that despite some of the hazards and side-effects mentioned above (it is simply not possible to cover all potential reactions due to the numbers and combinations of additives), most food additives are regulated in their use and therefore should not cause problems when processed foods are consumed in reasonable amounts by healthy humans.

So we conclude a brief, perfunctory (but hopefully interesting) excursion into the additives which help processed foods attain their pleasant textures, retain their colour and make commercial baked goods so consistent.