Abstract:
A method and apparatus to impart a random curvature to frying pre-formed snack pieces in a multi-layer fryer through the use of a contoured submerger. The shape of the contours of a contoured submerger imparts a random final curvature to each snack piece as snack pieces pass through a glass transition during frying. The contours are chosen so as to achieve a desired bulk density for the packaged fried snack products. Such method and apparatus are also useful in controlling the amount of change in bulk density or amount of settling of a packaged product during shipping or handling.

Description:
BACKGROUND  
       [0001]     1. Technical Field  
         [0002]     The present invention relates to a method to control the bulk density of packaged fried snack pieces. More specifically, this invention relates to imparting a random shape or curvature to each snack piece during cooking or frying in such a way as to control the resultant bulk density of such product when packaged.  
         [0003]     2. Description of Related Art  
         [0000]     Random Frying  
         [0004]     In the food industry, there are two typical methods of frying snack pieces such as potato chips: random frying and constrained frying. One popular random frying method is to fry uncooked pre-formed snack pieces in a random frying section of a multi-layer continuous fryer and allow buoyancy forces to impart a random shape or curvature to each snack piece. Several patents illustrate such random frying methods, as those disclosed in Pringle et al., U.S. Pat. No. 2,286,644 entitled “Method and Apparatus for Processing Potatoes” issued Jun. 16, 1942, and Anderson et al., U.S. Pat. No. 3,149,978 entitled “Process for Cooking Corn Dough in the Form of Chips” issued Sep. 22, 1964 and assigned to Arthur D. Little, Inc.  
         [0005]     U.S. Pat. No. 3,608,474 issued Sep. 28, 1971 to Liepa, discloses a random frying method for making potato chip products. Liepa &#39;474 suggests. slicing raw potatoes, cooking these loose slices in a reservoir of hot oil for a predetermined time where the slices are fried to a crisp state, and then removing the fried chips from the oil. The chips so prepared have a random surface curvature which is influenced by the diameter and thickness of the potato slices and is dependent both upon the amount of time the slices are immersed in the hot oil and the temperature of the oil. In the prior art, a constrained or form frying method is difficult to use with snack pieces of different sizes or shapes. Instead, random frying is typically used on these pieces of varying size or shape.  
         [0006]     Liepa &#39;474 also teaches that the random shapes which the chips assume require that they be randomly packaged. Random packing is used because it is relatively cheap, requires less energy and is less complicated than packing snack pieces into a high-density nested arrangement or packed alignment. Randomly packed snack piece packages require larger amounts of store shelf and consumer pantry shelf space. Generally, when a consumer opens such package, the snack pieces have settled and the bulk density has increased leaving a substantial void within the package. It would be ideal if the randomly packed pieces filled the entire package at the time the package is opened even after some settling occurred during shipping and handling.  
         [0007]     According to the prior art, and with reference to  FIG. 1 , uncooked chip pre-forms  120  are continuously fed by an entrance conveyor  110  into cooking oil  104  of a random frying section  106  of a continuous fryer  102 . In a continuous fryer  102 , cooking oil  104  generally flows from an entrance conveyor  110  toward an exit conveyor  114  carrying chip pre-forms  122  with it. As relatively moist chip pre-forms  122  are first introduced into cooking oil  104 , their weight  122  is usually greater than the buoyancy forces acting on them and the moist chip pre-forms  122  remain submersed in the oil without aid. As chip pre-forms  122  continue to cook and move along the path inside the continuous fryer  102  (from left to right in  FIG. 1 ), moisture escapes from the chip pre-forms  122  and the buoyancy forces become greater than the weight of the chip pre-forms  122 . At that point, the chip pre-forms  124  generally float near the surface of the oil as they approach a prior art submerger  112 . At this point, chip pre-forms  124  are generally, not rubbery, and do not have a tendency to stick to each other.  
         [0008]     A prior art submerger  112  generally turns at a speed slower than the flow of cooking oil  104 . A prior art submerger  112  usually has one or more optional and generally straight paddles, cleats or fins  116 . These fins  116  help gather the roughly monolayer of floating chip pre-forms  124  into a multi-layer of submerged chip pre-forms  126 . The fins  116  also help ensure that submerged chip pre-forms  126  do not clump or stick together. By submerging the cooking chip pre-forms  126 , the pre-forms  126  are more evenly cooked on both sides. Cooked chips  128  leave the prior art submerger  112  and exit the continuous fryer  102  on an endless exiting conveyor  114 .  
         [0009]     According to the prior art, reference to  FIG. 1   a,  the majority of submerged chip pre-forms  132  lay flat as they are transported along the cooking path. These pre-forms  132  leave the continuous fryer as generally flat cooked chips; any curvature in the cooked chips  128  is the result of random cooking forces acting on a submerged chip pre-form  132 . However, by chance a few submerged chip pre-forms  134  overlap or randomly press against a fin  116  or another submerged chip pre-forms  132  in such a way as to gain an exaggerated curvature.  FIG. 6  illustrates typical resulting shapes of triangular snack pieces cooked according to the prior art. The snack pieces  128  are generally flat, but some have a minimal curvature. More or less curvature can be obtained by using the method of constrained frying.  
         [0000]     Constrained Frying  
         [0010]     The other typical method of frying snack pieces is through the use of constrained or form frying. Several patents disclose methods of imparting a curvature to chip-type products made from a dough sheet by constrained frying methods. For example, a method to produce rippled chip-type products is disclosed in U.S. Pat. No. 2,286,644 by Pringle et al., issued Jun. 16, 1942 entitled “Method and Apparatus for Processing Potatoes.” Other U.S. patents disclose other similar methods to impart a desired final curvature or shape to a snack piece. In U.S. Pat. No. 3,998,975 issued Dec. 21, 1976, Liepa et al. discloses a method to form uncooked snack pieces into a desired shape by drying the pieces sufficiently and frying the pieces to a finished state before packaging.  
         [0011]     In U.S. Pat. No. 3,576,647 issued Apr. 27, 1971, Liepa discloses a constrained frying method wherein mold halves each provide multiple openings distributed over the mold surfaces to permit the frying oil to pass through and come into contact with the constrained food product. The mold halves cooperate to hold the dough sections and restrain them during the frying so that the fried products conform in surface curvature with that of the mold surfaces. Similarly, in related U.S. Pat. No. 3,608,474 issued Sep. 28, 1971, and U.S. Pat. No. 3,626,466 issued Dec. 7, 1971, Liepa discloses the same molds and passes them through frying oil and form-fries dough pre-forms into crisp chips thereby imparting a uniform size and shape to each chip.  
         [0012]     U.S. Pat. No. 3,520,248, issued Jul. 14, 1970 to MacKendrick, discloses a machine to continuously and uniformly cut and cook snack pieces or chips from a sheet of dough. MacKendrick discloses a machine to positively convey snack pieces through the frying medium in the same controlled manner as disclosed by Liepa &#39;474 where the resulting chips have a uniform color, texture, and shape. The MacKendrick invention improves the Liepa &#39;474 machine by using a reciprocating cutter in place of a rotary cutter which can be operated at significantly higher speeds.  
         [0013]     U.S. Pat. No. 3,149,978 entitled “Process for Cooking Corn Dough in the Form of Chips” granted on Sep. 22, 1964 to Anderson et al., teaches a method of imparting a controlled bent configuration to a corn masa dough chip which is cooked by deep-fat frying. Further, this invention teaches an apparatus for inducing a desired shape to the corn chips during cooking. The desired configuration is done through the use of a series of parallel wires which are mounted on a frame such that the wires may be controllably moved within the oil. The spacing of the wires is adjusted so that it is somewhat less than the diameter or maximum dimension of the chip which is to be cooked. The wires may be periodically immersed into the cooking oil to strike a portion of the cooking chips and then withdrawn. When forcing the parallel wires into the cooking oil, the wires impart a curvature to the chips either when the wires strike the chips, pushing them deeper into the oil, or when the chips rise after being pushed momentarily deeper into the cooking oil, or by a combination of these actions. By this process not all of the chips are contacted and bent. Anderson et al. &#39;978 teaches that it is preferred not to give a bend to all of the chips because it is desirable to package corn chips which are a combination of those having a flat and bent configuration, the latter amount consisting of about 25% to 75% of the total number of chips.  
         [0014]     In a recent U.S. patent application, Dove, et al. discloses a single mold fryer. A single layer of cooking chips are given a uniform shape as chips are disposed against a curved or contoured submerged conveyor surface or mold surface by buoyancy forces. The Dove patent application has the same assignee as the present application and is entitled “Single Mold Form Fryer with Enhanced Product” having a filing date of Jan. 21, 2003 and Ser. No. 10/347,993. Such form frying imparts a relatively predictable and uniform shape to each snack piece, not a random curvature.  
         [0015]     Anderson et al. &#39;978 mentioned above teaches that curvature must be imparted during frying before a critical time when the frying chips assume their permanent configuration or shape. This critical time occurs when a given dough formulation reaches a glass transition point.  FIG. 2  illustrates the various states of a generic polymer-like substance such as dough. Referring to  FIG. 2 , polymer substances and farinaceous dough formulations can be pliable  202 , rubbery  204  or glassy  208  at a given temperature depending on the composition of the substance. The state of a dough is especially dependent on moisture concentration. In a typical case, the state of an edible chip product made of a given dough formulation, as it loses moisture while cooking at a constant given temperature, moves from a pliable rubbery state  204  through a glass transition state  206  into a permanent glassy state  208 . As the chip is cooled and subsequently packaged, the chip remains in a glassy state  208 . It is at the glass transition state  206  where a cooking chip pre-form loses its pliability and assumes its final shape. The glass transition state  206  is somewhat of a misnomer since the term “transition” implies an equilibrium phenomenon that is invariant to the speed of the heating, cooling or other conditions. The actual transition point for a given product formulation may depend on the speed at which a substance is heated, cooled, or dehydrated (cooked).  
         [0000]     Packaging  
         [0016]     Cooked snack products are generally packaged in a random fashion in a bag or other similar container. Such random packing leads to a packaged product with a certain, relatively low bulk-density. Packages with low bulk density are essentially packages wherein the volume capacity of the package is much greater than the absolute volume of the snacks contained inside. The package could contain a much higher net weight of snack pieces than the volume capacity of the package if the pieces were not randomly packaged. This inefficiency is especially evident when chips have settled during shipping.  
         [0017]     Curved snack pieces generally have a lower bulk density when randomly packed as compared to generally flat snack pieces when randomly packed. Curved snack pieces tend not to seat against one another and tend to leave relatively larger voids between pieces as compared to flat snack pieces. In U.S. Pat. No. 4,844,919, issued on Jul. 4, 1989, Szwerc teaches that the use of curved pieces lowers packed product bulk density. Szwerc &#39;919 teaches that the snack piece&#39;s thickness, curvature, weight and orientation must be considered and potentially optimized to achieve densities above those obtained by randomly packing such pieces. Szwerc &#39;919 teaches the production of curved snack chips by baking. In U.S. published patent application Ser. No. 09/851040 entitled “Snack Piece Having Increased Packed Density,” Zimmerman et al. teaches that the shape and thickness of snack pieces can contribute to lower packed densities. Zimmerman teaches that the interference between adjacent snack pieces due to irregular sizing leads to increased space between nested pieces, subsequently leading to a lower bulk density.  
         [0018]     However, the prior art does not teach methods which would provide sufficient control of the snack piece&#39;s thickness, curvature, weight, orientation, or shape to achieve a desired bulk density. Currently, the food industry does not design a product to have desired bulk density. The food industry conforms the size of a product package to a desired weight of randomly-packed product. The package is sufficiently large to accommodate variations in bulk density. Consequently, a need exists for a method to permanently impart a particular shape to snack pieces in such a way as to produce a snack product that will have a desired bulk density when randomly packaged. Further, a need exists for producing such a snack product without lowering the productivity or throughput of the process.  
         [0019]     Further, a need exists for a method to control the amount of change in bulk density during the time a snack product package is exposed to settling forces during shipping and handling. Specifically, a need exists to prevent settling of chips wherein a substantial void remains in the product package. A need exists for an optimal packing that would also minimize breakage of chips. The benefit of filling this need would be an improved perception by consumers that the package is more substantially filled with product. Further, there is a need for loosely packed consumer products. In such a case there would be a lower bulk density and less shingling of chips within each package.  
         [0020]     Further, a need exists for a method and apparatus which cooks snack pieces with a more consistent, controlled, and predictable cooking time. Such method and apparatus would produce chips with a more uniform color and texture. Such a method and apparatus would meet these criteria and could be used in a high-speed production environment. It is therefore an object of this invention to provide a method of imparting a controlled bent configuration to fried snack product pieces. These and other objects will become apparent in the following detailed description.  
       SUMMARY OF THE INVENTION  
       [0021]     A method and apparatus are disclosed which provide packaged fried snack products having a desired bulk density without reducing production efficiency or throughput. Such method and apparatus are also useful in controlling the amount of change in bulk density or amount of settling of a packaged product when exposed to settling forces during shipping or handling. The shape of a contoured submerger imparts a random curvature to, and determines the final shape of, each snack piece before and during dehydration through the glass transition of the snack piece during frying.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]     The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein:  
         [0023]      FIG. 1  is a side cross-sectional view of a continuous fryer apparatus with a continuous submerging conveyor according to the prior art;  
         [0024]      FIG. 1   a  is a close-up view of the continuous submerging conveyor shown in  FIG. 1 ;  
         [0025]      FIG. 2  is a generic rubber/glass transition diagram for a polymeric substance such as a dough used for making snack pieces or chips showing temperature increasing from bottom to top on the vertical axis, and moisture content increasing from left to right on the horizontal axis;  
         [0026]      FIG. 3  is a side cross-sectional view of a batch fryer having a contoured submerger which imparts a random curvature to cooking chip pre-forms according to one embodiment of the present invention;  
         [0027]      FIG. 4  is a perspective view of two contoured submergers used in embodiments of the invention each with a different V-shaped contour profile or cross-sectional shape;  
         [0028]      FIG. 4   a  is a close-up view of one of the contoured submergers shown in  FIG. 4  showing a triangular chip pre-form pressed against one of the contours of the submerger;  
         [0029]      FIG. 5  is a side cross-sectional view of a continuous fryer apparatus with a continuous contoured submerging conveyor according to one embodiment of the present invention;  
         [0030]      FIG. 5   a  is a close-up view of a continuous fryer apparatus with a continuous contoured submerging conveyor according to one embodiment of the present invention;  
         [0031]      FIG. 6  is perspective view of triangular cooked snack pieces cooked under a flat submerger according to the prior art illustrating typical, slight, naturally-occurring curvatures of the cooked product;  
         [0032]      FIG. 7  is perspective view of triangular cooked snack pieces cooked according to one embodiment of the present invention showing randomly generated curvatures imparted by a contoured submerger;  
         [0033]      FIG. 8  is perspective view of a container of cooked snack pieces which were cooked under a flat submerger according to the prior art, and as shown in  FIG. 6 ;  
         [0034]      FIG. 9  is perspective view of a container of cooked snack pieces which were cooked according to the present invention under a contoured submerger, and as shown in  FIG. 7 ; and,  
         [0035]      FIG. 10  is a side cross-sectional view of various possible configurations of cross-sectional shapes of a contoured submerger according to the present invention. 
     
    
     REFERENCE NUMERALS  
       [0000]    
       
           102  continuous fryer  
           104  frying or cooking oil  
           106  random frying section of continuous fryer  
           108  submerging section of continuous fryer  
           110  entrance conveyor  
           112  prior art submerger  
           114  exit conveyor  
           116  paddle or fin  
           120  uncooked chip pre-form  
           122  frying chip pre-form  
           122  moist chip pre-form  
           124  rubbery floating chip pre-form  
           126  submerged chip pre-form  
           128  cooked snack pieces  
           132  submerged chip pre-form  
           134  submerged chip pre-form with exaggerated curvature  
           202  pliable state  
           204  rubbery state  
           206  glass transition state  
           208  glassy state  
           302  cooking chip pre-form  
           304  distance between subsequent contours  
           306  contours of the submerger  
           308  batch fryer oil  
           310  contoured submerger  
           320  batch fryer  
           402  chip pre-form conformed to contour of contoured submerger  
           404  contoured submerger having V-shaped contour profile  
           406  contoured submerger having V-shaped contour profile  
           512  contoured submerger  
           516  contours of contoured submerger  
           518  contour spacing  
           512  first contoured submerger  
           512  endless contoured submerger  
           526  cooking chip pre-form  
           528  shaped cooked snack piece  
           530  contour height  
           542  subsequent submerger  
           802  cylindrical container  
           804  void space  
           806  control snack piece  
           904  shaped snack piece  
           1002  V-shaped contour profile having uniform spacing  
           1004  V-shaped contour profile having non-uniform spacing  
           1006  sinusoidal contour profile having uniform spacing  
           1008  sinusoidal contour profile having non-uniform spacing  
           1010  crenellated contour profile having uniform spacing  
           1012  contour profile having tapered crenellations and non-uniform spacing  
           1014  contour profile composed of non-uniformly sized spheres  
           1016  contour profile composed of conical protrusions  
       
     
       DETAILED DESCRIPTION  
       [0086]     While the invention is described below with respect to a preferred embodiment, other embodiments are possible. The concepts disclosed herein apply equally to other systems for frying various types of pliable snack pre-forms and imparting a random curvature to each snack piece.  
         [0087]     The volume occupied by curved snack pieces is dependent upon the specific shape, dimensions, and arrangement of the individual snack pieces. In the present invention, randomly packed chips have a volumetric bulk density defined herein as the net weight of packaged snack pieces per the absolute volume of the container holding the snack pieces. Absolute volume, as used herein, is defined as the total liquid volume of the container holding the randomly packed snack pieces. As one example, the bulk density of randomly packed snack pieces can be measured by filling a cylindrical container of known volume and subsequently measuring the net weight of the container. The container is not packed or disturbed during the filling: the pieces may settle and ultimately take up less volume when exposed to settling forces. The bulk density after being exposed to such forces is termed the settled bulk density.  
         [0088]     To control bulk density of snack pieces formed from a dough sheet, it is necessary to control the shape and curvature of each piece. However, merely creating snack pieces with curvature does not always produce higher or lower bulk densities as compared to flat pieces. A snack piece&#39;s thickness, curvature, weight and orientation must be considered and potentially optimized to achieve a desired bulk density. A desired bulk density may be obtained by imparting a certain random curvature to each snack piece.  
         [0089]     Snack pieces generally achieve their final shape during their transition from a rubbery state to a glass state as pre-form snack pieces are cooked, usually by frying, as explained previously and with reference to  FIG. 2 . A random curvature can be imparted to each snack piece during frying in a batch fryer using a contoured submerger while each snack piece transitions from a rubbery state to a glass state.  
         [0090]     In one embodiment, and with reference to  FIG. 3 , chip pre-forms  302  are placed in a batch fryer  320  underneath a contoured submerger  310 . As the chip pre-forms  302  cook, they are maintained against the contours of a contoured submerger  310  by buoyancy forces acting on the cooking chip pre-forms  302 . The chip pre-forms  302  are given a random shape by the contours  306  of the submerger  310  as the chip pre-forms  302  are cooked. After a certain time, the cooked chips  302  are removed from the fryer  320  and may be further processed and packaged.  
         [0091]     In another embodiment and with reference to  FIG. 5 , chip pre-forms  120  are first introduced continuously into a random frying section  106  containing frying oil  104  in a continuous fryer  102 . As randomly frying chip pre-forms  122  lose sufficient moisture, typically having from 30 to 60 percent moisture when first introduced into the oil  104 , and having about eight to fifteen percent moisture by weight when reaching a contoured submerger  512 , they no longer have a tendency to stick to one another. At this point, the rubbery chip pre-forms  124  can be submerged beneath an endless contoured submerger  512 . If frying chip pre-forms  122  reach, and are cooked under, a contoured submerger  512  with a higher than about ten percent moisture content, either in a single layer or in multiple layers, sticking and/or clumping can occur.  
         [0092]     With reference to  FIG. 5 , in a preferred embodiment, as rubbery chip pre-forms  124  reach a contoured submerger  512 , the chip pre-forms  124  are aggregated and submerged for further cooking. An endless contoured submerger  512  generally does not cover the entire length of a random fryer  102 . Chip pre-forms made of cereal flour and/or tuber flour have a residence time from about 15 to 90 seconds. Submerged chip pre-forms  526  may overlap to a lesser or higher degree such that there are multiple layers of chip pre-forms  526  along the length of the contoured submerger  512 . While chip pre-forms  526  are losing moisture through cooking under the contoured submerger  512 , the chip pre-forms  526  are going from a rubbery state through a glass transition and into a glass state. The final shape of each piece is obtained as each chip reaches this glass state. For a typical dough formulation, when cooking chip pre-forms  526  have about five percent moisture by weight, these pre-forms may be removed from the contoured submerger  512  without affecting the final shape of the finished shaped chip product  528 .  
         [0093]     With reference to  FIG. 5 , a contoured submerger  512  in a submerging section  108  of a continuous fryer  102  has contours  516  differing substantially from the prior art. A contoured submerger  512  is not merely a submerging conveyor belt with fins, as shown in a typical prior art embodiment in  FIG. 1 . In one embodiment of the invention, a contoured submerger  512  has a V-shaped profile wherein each contour  516  has a contour height  530 . The distance between sequential contours  516  is the contour spacing  518 . In one embodiment, the contour spacing  518  is uniform from contour  516  to contour  516 . However, in other embodiments, the contour spacing  518  may be different between successive contours  516 .  
         [0094]     The contours  516  provide improved aggregation of cooking rubbery chip pre-forms  124  as they reach a first contoured submerger  512 . Generally, per unit length of conveyor, there are more contours  516  than submerger fins ( 116  in  FIG. 1 ). Contours are generally used in lieu of submerger fins and give improved functionality. With the use of contours  516 , each submerged chip pre-form  526  is forced under the oil  104  more consistently as the contours  516  of a first contoured submerger  512  engage the arriving rubbery chip pre-forms  124 . Since the contour spacing  518  is generally shorter than the distance between sequential fins on a prior art submerging conveyor, the submerged chip pre-forms  526  move along in improved plug flow.  
         [0095]     With reference to  FIG. 5   a,  while the cooking chip pre-forms are pressed upward against the contours  516  of a contoured submerger by buoyancy forces, these pieces conform to the curvature or shape of the contours  516 . Because each piece  526  is located at a random place along the contours  516 , a random shape is imparted to each piece  526 . A preferred random curvature, and resultant bulk density, is obtained when the spacing between adjacent contours  518  is larger than the largest dimension of each snack piece  526 . However, other spacing of contours  518  can be used to produce finished shaped pieces  528  having a desired bulk density. The final curvature of each shaped, cooked piece  528  is dependent upon the overall profile or shape of a contoured submerger  512 , the spacing between subsequent contours  518 , the number of layers of cooking pre-forms  526  beneath the submerger  512 , and the dough formulation and shape of each pre-form  526 . A contour depth  530  of a contoured submerger  512  may be any size and may vary from contour  516  to contour  516 . However, the contour depth  530  is preferably large enough to accommodate multiple layers of cooking chip pre-forms  526  while maintaining all such pre-forms  526  in plug flow as the contoured submerger  512  directs them toward a fryer exit conveyor  114 .  
         [0096]     In another embodiment, chip pre-forms  526  are maintained for a short duration in multiple layers on a first contoured submerger  512 . The duration depends upon the moisture content of the submerged cooking chip pre-forms  526 . The chip pre-forms obtain their final shape under a first contoured submerger  512  by passing into a glass state. At this point, cooking chip pre-forms  526  may pass to subsequent submergers without losing their shape. Subsequent submergers aid in cooking the cooking chip pre-forms  526  until they have a final desired moisture content; in one embodiment, a final moisture content is about two percent by weight. A final moisture content may be as low as one percent. Subsequent submergers may not be of the same shape, speed, contour, or size of a first contoured submerger  512 . Subsequent submergers may even resemble prior art submergers.  
         [0097]     In a further embodiment, submerged cooking chip pre-forms  526  are not in their final shape when passed to subsequent submergers. In such an embodiment, submerged chip pre-forms  526  obtain an initial shape from a first contoured submerger  512 , and their final shape from subsequent submergers. Such submerged chip pre-forms pass into a glass state under subsequent submergers. Finished shaped chip products  528  are removed from the cooking oil  104  on an exit conveyor  114 .  
         [0098]     Finished chip products  528  are subsequently packaged. Such finished chip products generally have a lower bulk density, and thus fill more of a container, even after finished chip product packages are exposed to settling forces such as during shipping and handling. Such lower bulk density generally provides finished chip products with higher consumer appeal than finished chip products having a higher bulk density.  
         [0099]     Various embodiments of a contoured submerger are envisioned.  FIG. 10  illustrates some of the various profiles or contours that may be used within the spirit of this invention. In certain embodiments, contours in a continuous fryer  102  generally lie perpendicular to the flow of chip pre-forms  302 . However, the contours may run in any direction, or may have no direction or may have no uniform shape at all. The contours may even lie parallel to the flow of oil and chip pre-forms  302  in a continuous fryer  102 . The contours may be composed of a non-repeating, non-continuous set of surface features.  
         [0100]     With reference to  FIG. 10 , in one embodiment, a contoured submerger has a V-shaped profile having uniform contour spacing  1002 , or alternatively, with non-uniform contour spacing  1004 . In an alternate embodiment, a contoured submerger has a sinusoidal profile with uniform contour spacing  1006 , or with non-uniform contour spacing  1008 . In still another embodiment, a contoured submerger has a crenellated profile  1010  that may or may not have uniform contour spacing. A variation of this embodiment is a contour profile having crenellations that are each tapered  1012 , and wherein the contour spacing may or may not be uniform.  
         [0101]     In another embodiment, a contoured submerger is composed of non-uniformly sized spheres  1014  or, alternatively, conical protrusions  1016 . In a variation of such embodiment, a contoured submerger may be composed of a variety of similar shapes and/or profiles described herein. A contoured submerger may also have three dimensional contour profiles such as, but not limited to, an egg carton-like profile having peaks and valleys at regular or irregular intervals. Such embodiments shown in  FIG. 10  are by way of illustration and not limitation. The following examples more fully illustrate the practice of the invention.  
       EXAMPLE 1  
       [0102]     In a first example, various contoured submergers having different shapes or contours were used to cook chip pre-forms shaped as equilateral triangles. With reference to  FIG. 3 , various shapes or profiles of a contoured submerger  310  were tested in a batch fryer  320  so as to affect the bulk density of a particular formulation and shape of snack piece. In this example, one contoured submerger  310  was shaped as a sinusoidal wave, and the bulk density of the resultant cooked snack pieces was about 7.5 lb/cu. ft. (0.0694 oz/cu. in.; 0.120 g/cu. cm) from that shape. Using a different contoured V-shaped submerger  310 , the resultant bulk density of snack pieces was about 6.25 lb/cu. ft. (0.0579 oz/cu. in.;0.100 g/cu. cm). Using various shapes of contoured submergers, resulting cooked and packaged chips had a bulk density over the range from about 6.0 lb/cu. ft. (0.0556 oz/cu. in.; 0.096 g/cu. cm) to about 7.5 lb/cu. ft. (0.0694 oz/cu. in.; 0.120 g/cu. cm) when cooked with these shaped or contoured submergers. Finally, a flat contoured submerger, as understood and routinely used in the prior art, was used to cook pre-form snack pieces of the same shape, the pieces cooked therewith serving as a reference. The bulk density from the use of the flat contoured submerger 310 was about 8.5 lb/cu. ft. (0.0787 oz/cu. in.; 0.136 g/cu. cm).  
       EXAMPLE 2  
       [0103]     In a second example of the present invention, two contoured submergers, differing from the submergers used in Example 1, and having different V-shaped profiles, were evaluated as to their effect on the bulk density of a snack product. Batches of snack product pre-forms in the shape of equilateral triangles were made from a dough sheet before being batch fried. The pre-forms in Example 2 were made from a dough formulation substantially different from that used in Example 1. The bulk density of pieces fried under the two contoured submergers in this example were compared against the bulk density of pieces fried under a control contoured submerger: a flat stainless steel perforated sheet or steel mesh. The two contoured submergers  404 ,  406  of Example 2 are shown in  FIG. 4  and both have V-shaped contour profiles. One contoured submerger  404  has contours with a larger contour spacing, or distance between successive contours, as compared to the other contoured submerger  406 .  
         [0104]     With reference to Table 1, batches of pre-form pieces were cooked with each of the three submergers described previously, and the resulting weight and volume were recorded for each sample. The control batches numbered 1-3 in Table 1 were cooked under the control or flat submerger. With reference to  FIG. 4 , the S1 samples numbered 1-3 in Table 1 were cooked with the submerger having the more narrow V-shaped contours  406  as compared to the contours  404  of the submerger used to cook the S2 samples numbered 1-3.  
         [0105]     Each batch of cooked chips of Example 2 were randomly packed into a rigid cylindrical container. Each batch received ten taps to simulate settling forces from shipping and handling. The volume after settling and the resultant settled bulk density of each batch are recorded in Table 1. For the control batches, the mean settled bulk density was 0.0506 ounces per cubic inch (oz/cu. in.) with a standard deviation of 0.0032 oz/cu. in. For the S1 samples, the mean bulk density was 0.0420 oz/cu. in. with a standard deviation of 0.0023 oz/cu. in. And for the S2 samples, the mean bulk density was 0.0366 oz/cu. in. with a standard deviation of 0.0010 oz/cu. in. These measurements of bulk density vary substantially from one another because of the differently shaped contours of the submerger used to cook the snack pieces.  
                                         TABLE 1                           Results from frying snack pieces with two different       V-shaped contoured submergers                        Volume   Settled Bulk   Settled Bulk           Weight,   Initial   after   Density,   Density,       Sample   g   Volume, L   Settling, L   oz/cu. in.   g/cu. cm               Control-1   302   4.0   3.7   0.0473   0.082       Control-2   334   4.0   3.8   0.0508   0.088       Control-3   353   4.2   3.8   0.0537   0.093       S1-1   259   4.0   3.8   0.0393   0.068       S1-2   285   3.9   3.8   0.0433   0.075       S1-3   278   3.9   3.7   0.0434   0.075       S2-1   256   4.2   4.0   0.0370   0.064       S2-2   246   4.1   4.0   0.0355   0.061       S2-3   245   4.1   3.8   0.0373   0.064                  
 
         [0106]      FIG. 8  and  FIG. 9  are drawings taken from photographs of pieces packed in a cylindrical container.  FIG. 8  shows control pieces  806  packed relatively densely. In  FIG. 8 , there are many snack pieces  806  which lie substantially parallel with one another. There is substantial settling as evidenced by the void  804  at the top of the container where chip pieces  806  initially filled the container  802 .  FIG. 9  shows S2 pieces  904  packed in an identical container  802 . There are many more void spaces and there is much less settling since there is very little void space formed at the top of the container  802 . The decreased bulk density, and thus larger volume of chips in the container, is generally preferred for appearance purposes by consumers.  
         [0107]     While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.