Cereals processing technology

216 Cereals processing technology
water is really the maximum quantity we can get into the dough and still be able
to mould the pieces and give bread of acceptable quality and depends on many
of the flour properties discussed above.
10.7.7 Improvers
This term covers any ingredient added to ‘improve’ the breadmaking potential of
a flour. Different breadmaking processes may utilise different flours and
therefore require different optimum improver formulations. Improvers of one
form or another have been used by bakers for over a hundred years and today
these products are a mixture of a number of different materials. Improver dosage
levels are also tailored to specific ingredient/product/process combinations.
The functional ingredients used in improvers vary but typically contain one
or more of the following ingredients:
• Oxidising agents to improve the gas retention abilities of the dough. The
functions of the oxidant are complex and at the protein molecule level are
related to the formation thought to be mostly related to ‘cross-linking’ of
proteins. This would be the equivalent of tying knots in the ends of short
pieces of string to gradually form a net. The contribution of oxidants to
bread quality is significant. By improving dough development we will get
larger product volume and improved crumb softness. In some processing
environments we can also get finer cell structure which will give soft bread
and a whiter crumb colour.
Following a number of changes in UK and EU legislation since 1990 the
only permitted oxidant is ascorbic acid (or Vitamin C). In the USA,
however, potassium bromate, azodicaronamide and other oxidants remain
available for addition by the miller and baker. The use of ascorbic acid in
breadmaking is not as straightforward as other oxidants such as potassium
bromate. Ascorbic acid is classed chemically as a reducing agent and can
only function as an oxidising agent in dough after it has been itself oxidised
to another form known as dehydro-ascorbic acid. To achieve this
conversion we require oxygen. In breadmaking the oxygen we require
for this conversion comes from air trapped in the flour and air bubbles
incorporated into the dough. Other dough ingredients use oxygen during
mixing, most notably the yeast.
• Reducing agents such as L-cysteine may be added to ‘weaken’ the dough
structure. It will only be used at low levels in improvers but by reducing
dough resistance to deformation it helps in moulding and shape forming, such
as with rolls and baps, without structural damage.
• Emulsifiers may be added to bread to improve its quality, each one acting
slightly differently and having its own special effects. There are four
commonly used emulsifiers; DATA esters, sodium stearoyl lactylate, distilled
monoglycerides and lecithins (Kamel and Ponte, 1993; Williams and Pullen,
1998).