Method of producing corrugated crisps

Method and apparatus for preparing a flat, formable product, such as a piece of milled corn-based product, having a soft, moist, and substantially fiberless consistency, with a corrugated shape. The apparatus comprises a pair of lower rollers, a pair of upper rollers and upper and lower forming elements extending in endless loops between the lower and upper rollers, respectively. The upper runs of the lower forming elements and the lower runs of the upper forming elements are staggered laterally and converge towards one another. Adjacent loops on the lower rollers and adjacent loops on the upper rollers converge towards one another. When the rollers are rotated the upper runs of the lower forming elements and the lower runs of the upper forming elements move forward synchronously. The piece is engaged between the opposed runs and in moving forward with the forming elements is pressed by the forming elements into a corrugated shape. At the same time the portions of the loops which engage the piece move laterally together so that substantially no lateral stretching of the piece occurs. Once the piece has been provided with a corrugated shape, the piece is fried to obtain a corrugated crisp.

BACKGROUND OF THE INVENTION 
This invention relates to a method of forming a formable product. It also 
relates to apparatus for use in such method. 
The invention finds particular application in the crisp-making industry in 
forming a milled corn product referred to as `masa`. Such corn product has 
a soft, moist, and substantially fibreless consistency which, after having 
been shaped into pieces of suitable size, is immersed in hot cooking oil 
to be fried. The invention could also find application in the forming of 
products, particularly food products, other than corn-based `masa` but 
having a similar consistency. 
It has been found that crisps provide a better bite when they are wrinkled 
or corrugated instead of being flat. It is therefore desirable to provide 
them with such shape. 
Potato crisps have been provided with a corrugated shape by slicing the raw 
potato with corrugated blades. Attempts to provide corn-based crisps with 
a corrugated shape have heretofore not met with success. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a formable product, and 
in particular corn-based crisps, with a wrinkled or corrugated shape. 
According to one aspect of the invention, there is provided a method of 
providing a flat, formable product with a wrinkled shape, which method 
comprises engaging the product between suitably shaped, opposed forming 
means, and, while bringing the forming means together to press the product 
into a wrinkled shape, causing the forming means to contract in a 
direction transverse to the direction in which they are brought together. 
Where the forming means each comprises a plurality of transversely spaced 
forming elements, said contraction of the forming means may take place by 
causing the forming elements to move transversely towards one another. 
The degree of contraction of the forming means may be chosen such as to 
minimise transverse stretching of the product as it is being pressed into 
said wrinkled shape. 
The product may be a food product having a soft, moist, and substantially 
fibreless consistency, and may, after it has been provided with said 
wrinkled shape, be fried to provide a crisp having a wrinkled shape. The 
product may be a milled corn product, i.e. `masa`. 
As mentioned above, `masa` is a soft, moist, and substantially fibreless 
corn product. It may be produced by cooking dried maize kernels, adding 
lime thereto to loosen the husks, steeping the resultant product for 10 to 
12 hours in water, washing it to remove the husks, and then milling it. A 
moisture content of about 55% has been found to be desirable. 
According to another aspect of the invention, there is provided a method of 
producing a wrinkled crisp, which method comprises pressing a flat piece 
of food product having a soft, moist, and substantially fibreless 
consistency, into a wrinkled shape in such a manner as to cause 
substantially no transverse stretching of the product, and thereafter 
frying the piece. 
Further according to the invention, there is provided apparatus for 
providing a flat formable product with a wrinkled shape, which apparatus 
comprises a pair of opposed, suitably shaped forming means displaceable 
towards one another so as to engage the product therebetween and press it 
into a wrinkled shape, the forming means being contractable in a direction 
transverse to the direction in which they are displaceable towards one 
another. 
The forming means may each comprise a plurality of laterally spaced, 
flexible forming elements, each arranged in an endless loop. 
Displaceability of the forming means towards one another may then be 
provided by arranging adjacent runs of opposed loops to converge towards 
one another so that, upon rotation of the endless loops, portions of said 
forming elements on said adjacent runs are displaced towards one another. 
Contractability of each forming means may be provided by arranging 
adjacent loops of the respective forming means to converge towards one 
another in the direction of convergence of said adjacent runs, so that, 
upon rotation of the endless loops as aforesaid, portions of the forming 
elements on adjacent loops are also displaced towards one another. 
The apparatus may thus comprise 
a lower entry roller; 
a lower exit roller spaced forwardly from the lower entry roller; 
an upper entry roller spaced upwardly from the lower entry roller; 
an upper exit roller spaced forwardly from the upper entry roller; 
one or more groups of laterally spaced flexible forming elements arranged 
in endless loops between the lower entry and exit rollers; and 
one or more groups of laterally spaced flexible forming elements arranged 
in endless loops between the upper entry and exit rollers; adjacent 
forming elements of each group converging towards one another in the 
direction of the exit rollers, and the upper runs of the forming elements 
on the lower entry and exit rollers converging towards the lower runs of 
the forming elements on the upper entry and exit rollers. 
The forming elements on the upper entry and exit rollers may be staggered 
laterally in relation to the forming elements on the lower entry and exit 
rollers so that portions of the lower runs of the elements on the upper 
entry and exit rollers can, during rotation of the loops, move inbetween 
portions of the upper runs of the forming elements on the lower entry and 
exit rollers. 
The forming elements may be in the form of helically coiled steel wire 
elements.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to FIGS. 1 to 3 of the drawings, reference numeral 10 
generally indicates forming apparatus comprising a lower entry roller 
12.1, a lower exit roller 12.2 spaced forwardly from the lower entry 
roller, an upper entry roller 14.1 spaced forwardly from the lower entry 
roller, an upper exit roller 14.2 spaced forwardly from the upper entry 
roller, a plurality of flexible forming elements 16 extending in endless 
loops between the lower rollers 12.1 and 12.2, and a plurality of flexible 
forming elements 18 extending in endless loops between the upper rollers 
14.1 and 14.2. As will be seen in the drawings, the upper entry roller 
14.1 is arranged forwardly of the lower entry roller 12.1, whereas the 
upper exit roller 14.2 is arranged rearwardly of the lower exit roller 
12.2. Also, the upper entry roller 14.1 is spaced further upwardly from 
the upper runs of the lower forming elements 16 than the upper exit roller 
14.2. The upper runs of the lower forming elements 18, and the lower runs 
of the upper forming elements 16 will therefore converge towards one 
another. The height of either the upper or the lower exit roller 12.2, 
14.2 may be adjustable as indicated, for example, by arrow 20 in FIG. 2. 
As will be seen in FIG. 10, the forming elements 16 and 18 are in the form 
of helically coiled steel wire elements. 
As will be seen in FIG. 4, the lower entry roller 12.1 has a number of 
spaced, circumferentially extending grooves 22 therein, each for 
accommodating one of-the lower forming elements 16. The grooves 22 are 
arranged in groups of seven, there being seven groups, one adjacent the 
other. It is to be understood, however, that there may be a different 
number of grooves in each group, and that there may be a different number 
of groups on the rollers. 
As will be seen in FIG. 7, the lower exit roller 12.2 also has a number of 
spaced, circumferentially extending grooves therein, here indicated by 
reference numeral 24. The grooves 24 are also arranged in groups of seven, 
there being seven groups on the roller. However, as will be seen in the 
drawing, the spacing between adjacent grooves 24 in each group is less 
than that between the grooves 22 on the entry roller 12.1. Thus, when the 
lower forming elements 16 are in position on the rollers 12.1 and 12.2, 
they will be arranged in groups of seven, adjacent elements in each group 
converging towards one another in the direction of the exit roller 12.2. 
Between adjacent grooves 24, the roller 12.2 is recessed circumferentially, 
as indicated by reference numeral 26. 
As will be seen in FIGS. 5 and 6, the upper rollers 14.1 and 14.2 have 
grooves 28 and 30 respectively therein, arranged in seven groups of six. 
The spacing between the grooves 28 and 30 respectively corresponds to the 
spacing of the forming elements 16 immediately below the respective 
rollers. Like in the case of the roller 12.2, the roller 14.2 is provided 
with circumferentially extending recesses, here indicated by reference 
numeral 32, between adjacent grooves 30. 
The upper forming elements 18 are accommodated in the grooves 28 and 30. 
In use, the entry rollers 12.1 and 14.1 are driven so that the upper runs 
of the lower forming elements 16, and the lower runs of the upper forming 
elements 18 move forwardly towards the exit rollers 12.2, 14.2 at the same 
speed, i.e. synchronously. 
Flat, disc-shaped pieces 34 of corn-based `masa`, just over 2 mm in 
thickness, are produced by machinery known in the art, and are deposited 
on the upper runs of the lower forming elements 16. The pieces 34 are 
transported by the elements 16 towards the exit rollers 12.2, 14.2. As 
each piece 34 nears the longitudinal position of the upper exit roller 
14.2, it is engaged by the upper forming elements 18, as indicated in FIG. 
8. 
Upon further forward displacement, the converging forming elements 16 and 
18 press the piece 34 into a corrugated shape, as indicated in FIG. 9. 
While being so pressed into a wrinkled shape the forming elements 16, 18 
also move together laterally as indicated by arrows 36 in FIG. 8. The 
angle of convergence A (see FIG. 2) between the adjacent runs of the 
forming elements 16 and the forming elements 18, and the angle of 
convergence B (see FIG. 3) between adjacent forming elements 16, 18 in 
each group, is chosen such that there is substantially no lateral 
stretching of the `masa` as the pieces 34 pass through the apparatus. This 
will ensure that the pieces 34 remain intact. 
When the pieces 34 have passed underneath the upper exit roller 14.2 they 
have the desired corrugated shape. They are carried further forwardly for 
a short distance on the forming elements 16, up to and over the lower exit 
roller 12.2, and from there they drop into hot cooking oil where they are 
fried. The longitudinal wrinkles are effective to stiffen the pieces, 
ensuring good separation of the pieces from the forming elements 16 as the 
forming elements 16 pass over the roller 12.2. 
From this point onward, the pieces 34 are processed by methods known in the 
art, until crisps are obtained as an end product. 
The recesses 26, 32 are provided to prevent the rollers 12.2, 14.2 from 
touching the pieces 34 as they pass through the apparatus.