Cereals processing technology

Breadmaking 223
devices which roll the dough piece from one pocket to another. This action
allows the temporarily empty pocket to dry.
Final moulding
The key functions of the final moulder are to shape the dough to fit the product
concept and to re-orientate the cell structure. The essential features of the final
moulder are:
• Passage of the round dough piece through sets of parallel rolls moving at high
speed. Sheeting reduces the thickness of the dough piece. The gap between
successive pairs of rolls decreases and on leaving the last gap the dough piece
has an ellipsoid shape. It is essential that the dough piece is presented
centrally to the rollers and is maintained centrally throughout the moulding
process (Collins, 1993; Cauvain and Collins, 1995).
• Curling of the ellipse by trapping the leading edge underneath a static chain
which creates a ‘Swiss roll’ of dough.
• Compression and further shaping of the Swiss roll to give a uniform cylinder
of dough. This is achieved by compressing the dough piece underneath a
pressure board while it is still being moved along the length of the moulder
by the action of a moving belt.
Given the above description of the final moulding operation it is clear in order to
achieve the necessary product quality the dough must have appropriate rheology
(i.e. have a low resistance to deformation). This is particularly true when starting
from a rounded dough ball. A cylindrical dough piece with square ends and a
length and diameter equal to the length and width of the bottom of the pan is
required for many bread types. Modification of the dough piece make take place
at the end of the final moulder. One common form is ‘four-piecing’ in which the
dough cylinder is cut into 4 equal lengths (each equal to just less than the tin
width) and turned through 90º to lie side by side across the tin. This techniques
re-orientates the cell structure in the final bread crumb. Cross-graining also
performs this function by turning the dough sheet through 90º as it passes
through the final moulder so that the wider plain of the elliptical sheet is
presented to the curling chain and moulding board.
10.8.5 Gas bubble control during dough processing
A key feature of no-time doughs is that major degassing of the dough does not
occur and indeed should be discouraged. Little change occurs to gas bubble
populations during dividing and first moulding operations while in intermediate
proof the size of the gas bubbles increases as the carbon dioxide gas diffuses into
the gas bubbles present (Whitworth and Alava, 1999).
It is in the final moulding stages that any significant changes occur in the gas
bubble populations. There are two main changes: one is a potential elongation of
gas bubbles and the other a slight, though potential important degassing, during
sheeting. As the round dough piece passes through the sheeting rolls some