Baking & Snack - December 2006 - 69

PROCESSING TECHNOLOGY

dough in the laminator. This ultimately results in layering the crumble between the sheets of dough to give the
dimpled cell structure characteristic of cream crackers.

ᮢ This complete
sheeting/laminating
line includes multiple
laminating and gauging stations all of
which are adjustable
to match product
requirements.
TROMP BAKERY EQUIPMENT

DOUGH EXTRUDER. A feed conveyor leads through a
chunker such as a star wheel or a guillotine to cut pieces
from the dough mass. A transfer conveyor system provides a period of time for the dough to relax after mixing,
and ambient condition control at this point can provide
in-line retarder capability.
Dough chunks feed into a hopper for an extruder producing the continuous ribbon of dough. The design of
the system forming the dough ribbon varies depending
on individual equipment company and customer preferences, but they all share the philosophy that minimal
stress application is important in this stage. The extruder
may be of a 2-, 3-, 4- or 5-roll design; several equipment
suppliers explained that the extruded dough thickness
depends upon the number of rolls. Two- or 3-roll sheeters
extrude at approximately 30 to 35 mm while a 4- or 5-roll
sheeter may yield a thickness up to 55 mm.
One supplier explained that the higher number of rolls
handle softer dough more easily and apply less stress. If
a fine and regular cell structure is the target, then adjustment of the feed roll speeds vs. the finishing roll speed
and gap may be used to apply pressure and work in the
compression chamber. The supplier of cracker lamination systems puts a pressure sensor in the side wall of the
3- or 4-roll sheeter chamber, which provides operators
with information about operating conditions and dough
viscosity. This detects dough changes that may disrupt
operations downstream.
The other cracker equipment manufacturer described
a 3-roll sheeter having three cavities with each cavity able
to feed dough with different flavor or color. This results
in a sandwiched dough sheet that has unique appearance
or flavor-delivery ability. The dough rheology needs to be
similar in elasticity and extensibility to ensure compatibility of the individual component layers, but they will
display a visible layered appearance.

72 / BAKING & SNACK / December 2006

ᮡ Cut sheets of dough are overlapped by means of a retracting conveyor.
Final dough could include up to 144 layers of dough and fat.
BAKER PERKINS

FAT APPLICATION. Width of extruded sheets range
from less than 36 in. up to 60 in., depending on the total
throughput of the line and whether the sheet is folded or
separately formed and conveyed to top the fat layer. Folding reduces the sheet width to approximately half the
original width. Fat is applied to the sheet surface through
a manifold with a slit die of varying thickness; the percent of fat, controlled by the slit gap dimension, varies
from 15 to 35%, depending on the product. When the
dough sheet is folded to cover the fat ribbon, the width of
the fat application is typically slightly less than one half
the width of the sheet. Even distribution of fat across the
dough sheet is important to avoid "dead areas" without
fat that will display a dark, uneven bake.
In a number of systems, a pressing roll creases the
dough in preparation for folding the uncoated portion
of the sheet over the fat-coated dough. The folding action
may be controlled by either driven or static folding belts.
Driven folding belts, or ploughs, fold the dough from the
center to the outside edge but in an alternative design,
dual folding may occur with the right side and left side
of the dough folded over the fat-coated center area with
the outside edges overlapping to seam together over the
middle of the fat strip. An alternative method has two
continuous dough ribbons being produced by slitting a
single extruder dough ribbon in half or two successive
multiroll extruders with one of the ribbons being positioned on top of the lower fat-carrying dough ribbon.
After the dough-encased fat laminae have been formed,
it is gently reduced using one of the various reducing systems. But the thickness of the dough-fat-dough sandwich
can be upward of 1.125 in., and the process of reduction
to less than 0.25 to 0.5 in. should be gradual through the
use of multiple sheeting stations.
It is at this point in the process that the first right-angle
turn of the dough or layering of the dough-fat-dough

Baking & Snack - December 2006

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