Agriculture Reference
In-Depth Information
characteristics of major wheat-based foods, and
then to focus on the principles of current and
emerging technologies that can be used by all seg-
ments of the industry to assess grain and fl our
functionality.
The procedural intricacies of the techniques
have been reviewed elsewhere (e.g., Rasper and
Walker 2000) and can also be examined in pub-
lished standard methods (AACC 2000; ICC 2006).
Here these techniques will be viewed as tools to
ensure that wheat “passes the test” on functional-
ity and, where possible, new analytical methods
and predictive tools that are aimed at improving
the speed, accuracy, and precision of grain func-
tionality assessments will be highlighted. Where
the outputs of specifi c functional tests are men-
tioned in the fi rst section on the characteristics of
wheat-based foods, readers are directed to the
relevant later sections, for example, on “Starch
and fl our properties” and “Dough testing and
prediction of dough properties,” for explanations
of the specifi c terms used.
tents for different products. For example, most
fl ours used for pan breads have higher optimum
fl our protein content than fl ours destined for
cookies (biscuits). Arguably most important,
fl our should have appropriate gluten composi-
tion—or in colloquial terms, protein quality—
and therefore appropriate dough characteristics
for end-use processing.
Essential bread requirements
Leavened and unleavened breads share a common
group of processing requirements and end-
product traits, the precise nature of which varies
between bread types. All breads require fl our that
makes dough of a dependable and relatively soft
consistency that can be easily molded into the
desired shape, at a level of water absorption that
allows the dough to be cohesive and elastic without
undue stickiness. However, there is much varia-
tion in optimum water requirement, from as high
as 70%-80% (fl our basis; fb) for ciabatta, to as
low as 55% (fb) for Arabic breads (Qarooni 1996).
A key requirement of bread dough is that its
elastic and viscous rheological behaviors are bal-
anced. The desired end point is a dough that is
strong enough to withstand the rigors of process-
ing (mixing, fermentation, dividing, molding),
and for leavened breads, the dough must be strong
enough to hold the fermentation gases during
proofi ng and yet deformable or extensible
enough to rise easily and form the familiar aerated
internal structures (crumb) in the fi nished
products.
CHARACTERISTICS OF MAJOR WHEAT-
BASED FOODS
Most modern wheat-based foods are made from
ground or milled wheat rather than the whole
berries. Milled wheat can be used as is, as whole-
wheat fl our (wholemeal), or as fl our of greater or
lesser levels of refi nement. Flours range from
atta, basically a wholemeal with the coarse bran
removed (Quail 1996), to the fi nest of white
patent fl ours that consist largely of only the
central endosperm (Posner 2000). In durum
milling for pasta production the desired end
point is semolina, which has a coarser particle-
size distribution than fl our. Color should be
appropriate to the level of fl our refi nement (e.g.,
whole-wheat fl our is expected to have a brown
hue and to be less bright than refi ned white fl our).
Flours or meals should have moisture content of
less than 14% to maintain storage stability (pri-
marily to restrict mold growth) and to ensure that
fl our fl ows without caking or clumping during
transfer in mills and bakeries (Atwell 2001).
Flours should also have specifi ed protein con-
Straight-dough processes
Straight-dough breadmaking processes are the
basic template for bread production. In this
process all of the fl our, water, and other ingredi-
ents are mixed together into dough in one step.
The dough is then fermented fully and can
be optionally degassed (punched or folded) at
different times during fermentation (Cauvain
and Young 2007). Straight-dough processes are
used to make a large variety of breads, from
white sandwich pan bread made by rapid dough
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