Cereals processing technology

• Enzyme active materials have become important to many sectors of the
baking industry following the limitations placed on the use of oxidants. Those
most commonly used are the -amylases (fungal, cereal and bacterial) and
the hemicellulases. Proteolytic enzymes may be used in the USA (Kulp,
1993).
• Full fat, enzyme-active soya flour has been used as a functional dough
ingredient in the UK since the 1930s. It has two principal beneficial
functions, both arising from its lypoxygenase enzyme system. They are to
bleach the flour and assist in dough oxidation.
Mould inhibitors and preservatives are added to delay the spoilage of bread and
fermented products, all of which have high water activities (Pateras, 1998;
Williams and Pullen, 1998). Amongst the most common are propionic acid and
calcium propionate. Acetic acid (vinegar) may also be used.
10.8 Current mixing and processing technologies
Breadmaking 217
The essential features of the two main breadmaking processes have been
described above and these continue to form the basis of current mixing and
processing technologies. In both of these breadmaking processes mixing plays
a major role on forming and developing the gluten structure in the dough and
incorporating the necessary gas bubbles for cell structure formation in the
baked product. It is the latter which makes bread a light, aerated and palatable
food.
10.8.1 The functions of mixing
In essence mixing is the homogenisation of the ingredients, whereas kneading
is the development of the dough (gluten) structure by ‘work done’ after the
initial mixing. However, in the context of modern breadmaking both processes
take place within the mixing machine and so can be considered as one rather
than two processes. This is especially true of the two main no-time dough
processes considered in this chapter since around 90% of the final bread is
determined by the mechanics of mixing and the reactions between the
ingredients which take place in the mixer.
The sub-processes taking place during mixing can be summarised as follows:
1. The uniform dispersion of the recipe ingredients.
2. Dissolution and hydration of those ingredients, in particular the flour
proteins and the damaged starch.
3. The development of a gluten (hydrated flour protein) structure in the dough
arising from the input of mechanical energy by the mixing action.
4. The incorporation of air bubbles within the dough to provide the gas bubble
nuclei for the carbon dioxide which will be generated by yeast fermentation
and oxygen for oxidation and yeast activity.