Cereals processing technology

134 Cereals processing technology
7.2.2 General flour characteristics
In many countries the noodle manufacturer’s source of flour is usually dictated by
price and a guarantee that it will perform adequately. A fine flour (less than
130 m) with a uniform particle size distribution is required for all noodle
production as it ensures uniform water distribution within a specified mixing
period. Coarser flour absorbs water at a slower rate while extremely fine flour,
often having high starch damage, absorbs water too quickly. 14 The various noodles
have their own flour protein specifications as their textural attributes are
significantly correlated with protein content. Aside from protein quantity, protein
quality is an important factor, especially from the processing perspective. Gluten,
the viscoelastic protein composite which results from the mixing of gliadin and
glutenin proteins, must have sufficient strength to handle multiple sheeting passes
without tearing yet retain elasticity to avoid excessive shrinkage after rolling.
Research has indicated a very strong correlation between whole meal flour SDS
sedimentation results and the noodle textural characteristics maximum cutting
stress (bite) and maximum compression stress (chewiness) for both white salted
and yellow alkaline noodles. 15 Wheat lacking the gliadin protein electrophorogram
bands 44.5 or 45.0 were found to be of poorer quality for either noodle type. The
addition of both alkaline and/or salt to the noodle dough increases its toughness
which is reflected in the amount of work/energy input required for processing. In
the flourishing instant noodle market, protein content is negatively correlated with
oil uptake during processing and thus presents a unique fiscal consideration and
increasing health concern. 16
Starch plays a key role in the structure and texture of noodles, especially the
white salted noodles such as the Japanese Udon. The special softness but unique
elasticity associated with these noodles is associated with their high swelling and
high paste viscosity starch. These characteristics are variety dependent forcing
millers to stipulate varieties when importing wheat. 17 Two currently popular
Australian varieties are Eradu and Cadoux. Udon manufacturers in Japan and
Korea stipulate a minimum 700 BU peak viscosity for their flour purchases. 16
Work by a number of researchers 18–22 have actually shown that high swelling
starch flours are not desirable for alkaline noodles.
7.2.3 General processing characteristics
Minimal improvements in front-end processing technology and equipment have
been observed in recent years with the key differences to various products being
confined to the latter stages of processing. 23 A general process flow diagram can
be seen in Fig. 7.1.
Commercially, the addition of the correct amount of water to form the dough
requires a 30–35 percent range with the mixing time restricted to less than
20 min. 23 The physical operation of a large-scale commercial mixer generates
greater heat output elevating the temperature of the dough, which in turn
becomes soft and sticky, and subsequently causes difficulties during sheeting. In
some operations the amount of water added is reduced to counter the softening