Agriculture Reference
In-Depth Information
(Huang et al., 1996), and overall bread quality
improved with increased fl our protein content up
to around 10% protein in either soft or hard
wheats (Rubenthaler et al., 1990; Huang et al.,
1996). Quality leveled off thereafter with very
high protein fl ours showing decreased overall
quality (Huang et al., 1996). He et al. (2003)
concluded that fl our and dough with me-
dium protein content, medium-to-strong gluten
strength, and good extensibility were best for
northern style steamed bread made by a mechan-
ical mixing process. Weaker doughs performed
better for hand mixing. Whiter fl our with higher
fl our cooked-paste viscosity could also enhance
northern style steamed bread quality (Crosbie et
al., 1998; He et al., 2003). In addition to being
softer in texture, southern style steamed bread
has a more open crumb structure. Accordingly,
fl our of slightly lower protein content (9.5%-
11% compared with 10%-12% for northern
style) and of medium dough strength is more
suitable (Crosbie et al., 1998). For the very soft
and friable Guandong style bread, very white
fl our of 7.5%-8.5% protein with weak to medium
dough strength is required (Crosbie et al.,
1998).
some quality benefi ts from using a sponge-and-
dough process. Arabic bread is made from a rela-
tively stiff dough (650-850 BU consistency on a
farinograph, C.W. Brabender Instruments, Inc.
South Hackensack, New Jersey) consisting of
water, yeast, salt, and a high-extraction (75%-
80%) fl our (Qarooni 1996). The dough may be
sheeted or die-cut into its fi nal shape (Quail 1996).
The relatively dry and stiff dough easily forms a
skin in fi nal proofi ng and in the initial stages of
the typically high temperature (350-600 ºC)
baking. The skin then forms a barrier preventing
escape of the steam and thus allows an increase in
the gas pressure in the baking dough piece. It is
this pressure that splits the single dough piece
into two layers, preferably of even thickness
(Qarooni 1996; Quail 1996).
Arabic bread should be soft and fl exible with
well-separated layers. Each layer should have
only a thin adhering layer of crumb that has a fi ne,
even structure. The bread should have smooth,
brown, and blister-free surfaces. The intensity
and desired hue of the crust's brown color varies
depending on bread type and local preferences.
Bread softness and fl exibility should be accompa-
nied by some strength to allow rolling and folding
of the bread without cracking or tearing (Qarooni
1996; Quail 1996).
In contrast to the linear increase in loaf volume
with increasing fl our protein content described
for pan bread, overall quality of Arabic bread has
been shown to have a roughly parabolic response
to increased fl our protein (Qarooni et al., 1988;
Quail et al., 1991). Optimum fl our protein content
ranged from 10.5% to 12% with distinct declines
in Arabic bread quality above 12% or below 9%.
Moderately strong and extensible dough was con-
sidered most suitable (Quail 1996). Higher dough
strength or dough elasticity was found to produce
bread with a leathery texture. It can be concluded
that Arabic bread is sensitive to changes in dough
strength and elasticity and that there appears to
be a threshold of dough elasticity beyond which
a rapid decline in bread quality takes place
(Qarooni et al., 1988; Quail et al., 1991; Toufeili
et al., 1999). In our experience (A.S. Ross, unpub-
lished data), overstrong doughs resist sheeting.
Low-volume bread types
Low-volume or fl at breads are common through-
out the continent of Asia and in North Africa
and are also found in a multitude of types. A
major contrast within fl at breads is the distinc-
tion between the two-layered types generically
known as Arabic breads (pita) and one-layered
types (e.g., barbari, chapatti, tanoor, lavash)
(Qarooni 1996; Quail 1996). The general category
of fl at breads can also include fl our tortillas
and bread types with intermediate ratios of
crust-to-crumb such as foccacia and ciabatta
(Qarooni 1996).
Two-layered bread
Two-layered Arabic bread is commonly made by
straight-dough processes (Qarooni 1996; Quail
1996). However, Amr and Ajo (2005) showed
