We have been experiencing some variation in crust colour on our bread products What causes bread crust colour and why should it vary

The crust colour in bread is principally formed by Maillard-type reactions involving reducing sugars and amino compounds (free amino acids and terminal amino-groups in soluble proteins). For colour formation you need both factors to be present in appropriate amounts.

A small amount of the main reducing sugar, maltose, may be present in the flour but in fermentation, proving and the early stages of baking the alpha- and beta-catalysed hydrolysis of the starch in the flour increases the amount present. Amylases are slow to attack intact starch, so the main source of starch for hydrolysis is the damaged starch. Thus, the balance of enzymic activity and flour starch damage becomes important for correct crust formation.

Other sugars that may contribute to colour formation are glucose and fructose, sucrose or lactose if non-fat milk solids are present in the recipe. Caramelisation may also occur, even in the absence of Maillard-type reactions but it occurs at much higher temperatures, usually above 155 °C.

The variations in colour that you are experiencing may therefore come from a number of sources. Assuming that the baking conditions are not to blame then the most likely causes are variations in damaged starch levels in the flour or enzymic activity, whether in the flour or from the improver. You may want to have these checked.

Remember that enzymic activity is temperature sensitive so that variations in dough temperature may contribute to variations in crust colour. Processing delays may cause darker than usual crust colours because of the longer time available for enzyme action. Even retarded doughs can show problems of dark crust colours because of enzyme activity in the dough. If you are using a fermentation process to develop your dough you should check that the bulk time is being carefully controlled.

There are generally adequate amounts of naturally occurring amino compounds in bread flour, but if you continue to get pale crusts then an addition of non-fat milk solids or an ammonium salt will help. Reducing a dark crust is harder to achieve because it requires the removal of material that may already be in the flour or improver.

6.13 Why is the surface of some bread doughs cut before baking?

Many types of breads, especially crusty forms, have a distinctive pattern of cuts showing on the baked surface. These cuts are usually made when the dough leaves the prover and before it enters the oven.

The most obvious reason for the cuts is to provide a distinctive surface pattern which distinguishes one loaf from another. The characteristic patterns will have originated many years ago and has now become so enshrined in the product character that they have become part of the authenticity of a particular product and part of consumer perception of product quality. If it has been cut like a bloomer and baked like a bloomer then at first glance in a display of other breads it meets customer expectations of a bloomer and customers will be attracted to it.

Probably surface cuts were first used for quite different reasons. While dough proves, its rheology begins to change and in particular it becomes less elastic. If doughs enter the oven under-proved the elastic nature of the dough prevents uniform expansion. Cutting the surface of dough pieces creates points of weakness which can be exploited by the expanding dough so that cutting can be used to produce controlled oven spring. A rule of thumb is that if doughs are not fully proved you cut deeply, while if doughs are over-proved you make the cuts shallow.

There is a common tendency to worry about cutting doughs deeply because they may collapse and fail to rise in the oven. The main cause of such collapse is not usually the cutting (unless the doughs are over-proved) but rather that the doughs lack gas retention. Doughs that have been fully developed can be cut quite deeply and even if they collapse after cutting they will regain their correct size and shape in the oven.

Bread doughs bake by receiving heat through their surfaces. Because dough is a poor conductor of heat, one way to speed up heat transfer is to increase the surface area available for heating by cutting the dough. This increase in surface area also helps with flavour development in the product because cutting often increases the proportion of crust relative to that of the crumb. Since much of the bread flavour comes from the crust, the greater the proportion of crust, the more flavoursome the product.

Cutting should always be carried out with a clean, sharp knife and should follow the traditional pattern closely. Each bread type will have its own distinctive pattern and method of making the incisions and without the right procedure then you will not get the authentic product.

Continue reading here: What are the best conditions to use for proving bread dough

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