Abstract:
A lattice-cut potato product is sliced so that the ridges and grooves on one surface of the slices are oriented transversely to the ridges and grooves on the opposite surface of the slices. The sizes and shapes of the ridges and grooves are particularly selected so that each point in the interior of a slice is no greater than a specified distance from an outer surface of the slice. These parameters enable a lattice-cut potato product to consistently achieve a crispy outer surface and a smooth and creamy interior when cooked by baking or microwaving.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention is related to lattice or waffle cut vegetables, particularly potatoes, and to an apparatus for cutting same. More particularly, the invention is related to processed lattice cut or waffle cut potatoes that have a crispy texture following cooking. Still more particularly, the invention is related to lattice cut or waffle cut potatoes that achieve a crispy cooked texture without frying. 
       BACKGROUND OF THE INVENTION 
       [0002]    The manufacture of French fries tends to follow a basic process of washing, peeling when desired, cutting, blanching in hot water or steam, drying, frying and freezing or chilling. This process, as disclosed in U.S. Pat. No. 3,397,993 and U.S. Pat. No. 3,472,591, was originally developed to provide French fries for the foodservice market. Corrugated or lattice-cut French fries have been produced by a similar process. Since that time, a trend has developed to live a healthier lifestyle. That trend has included a reduction in the consumption of fried foods. Acknowledging this trend, many restaurants and others in the foodservice industry have reduced or even eliminated their offering of fried foods. Despite this trend, there is still a strong demand in the foodservice industry for a crispy potato side dish. The foodservice industry has attempted to meet this demand with a thin lattice-cut French fry or chip that portrays an upscale image, and that can be cooked without frying, such as in an oven or by microwave. 
         [0003]    The processes used today for manufacturing both ovenable and microwavable lattice-cut chips are derivatives of the existing frying processes. Despite the advantages these products may provide, chips cooked in an oven or by microwave have produced inferior results to those cooked by frying in oil. That is, chips that are fried in oil consistently have a crispy outer layer with a smooth and creamy interior. In contrast, it is difficult to consistently obtain a crispy surface texture on chips that are baked in a conventional oven or by microwave. 
         [0004]    There therefore is a need for improved processed chips which can be baked in a conventional oven or in a microwave, but that will exhibit a crispy surface texture reminiscent of fried French fries on a consistent basis. In particular, there is a need for such products in a lattice-cut form. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    The present invention addresses these needs. 
         [0006]    One aspect of the present invention provides a method of preparing a potato-based food product. The method includes cutting potatoes into slices having first and second major surfaces, the first surface having a plurality of ridges and grooves extending in a first direction, and the second surface having a plurality of ridges and grooves extending in a direction transverse to the first direction, the potato slices having an interior surrounded by an exterior surface, each point in the interior being no more than a predetermined distance from a point on the exterior surface. The potato slices may then be blanched, dipped in a solution to prevent nonenzymic oxidation of the potato slices, dried, parfried, and packaged. The plurality of ridges and grooves in the second surface may be substantially orthogonal to the plurality of ridges and grooves in the first surface. 
         [0007]    The blanching step may include heating the potato slices in a water bath at a temperature of between about 150° F. and about 200° F., for a time between about 5 minutes and about 20 minutes. 
         [0008]    The method may include additional steps. One additionally step is freezing of the potato slices. Another additional step is cooking the potato slices without frying. The cooking step may include heating by warm air, or heating by microwave energy. A further step may include preheating the potatoes to soften the potatoes prior to the cutting step. 
         [0009]    The predetermined distance may be between about 0.055 inches and about 0.175 inches. Preferably, the predetermined distance is about 0.110 inches. 
         [0010]    Each ridge may have a longitudinal peak, the peaks on the first surface being spaced from the peaks on the second surface by a peak-to-peak thickness measured in a direction substantially orthogonal to the first and second surfaces, the peak-to-peak thickness being between about 0.110 inches and about 0.350 inches. Preferably, the peak-to-peak thickness is about 0.220 inches. 
         [0011]    The grooves on the first surface may intersect with the grooves on the second surface to define a plurality of openings extending through the slice. 
         [0012]    Another aspect of the present invention is a lattice-cut potato product produced according to the foregoing methods. 
         [0013]    Yet a further aspect of the present invention is a cutting blade for cutting potatoes. The cutting blade includes an elongated body having a cutting edge and opposed inner and outer sides, each side having a plurality of alternating longitudinal ridges and grooves extending substantially perpendicular to the cutting edge. Each ridge has a longitudinal peak, the peaks on the inner side being spaced from the peaks on the outer side by a peak-to-peak thickness measured in a direction substantially orthogonal to the first and second sides, the peak-to-peak thickness being between about 0.108 inches and about 0.118 inches. Preferably, the peak-to-peak thickness is about 0.113 inches. Each ridge and each groove may have a radius of curvature of about 0.100 inches. 
         [0014]    In a preferred cutting blade, an interpeak distance between one peak on the inner side of the body and a next adjacent peak on the inner side of the body is between about 0.328 inches and about 0.380 inches. An interpeak distance of about 0.345 inches is more preferred. 
         [0015]    Preferably, a ratio of the interpeak distance to the peak-to-peak thickness is between about 2.90 and about 3.36. More preferably, the ratio of the interpeak distance to the peak-to-peak thickness is between about 3.00 and about 3.20. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    A more complete appreciation of the subject matter of the present invention and the various advantages thereof can be realized by reference to the following detailed description, in which reference is made to the accompanying drawings in which: 
           [0017]      FIG. 1  is a top plan view of an apparatus for manufacturing a lattice-cut potato product according to the present invention; 
           [0018]      FIG. 2  is a perspective view of the apparatus of  FIG. 1  with the cutter assembly and cover thereof removed and the hopper thereof disposed in an inoperative position; 
           [0019]      FIG. 3  is a vertical cross-sectional view taken along line 3-3 of  FIG. 1 ; 
           [0020]      FIG. 4  is an enlarged plan view showing the operative relationship of the carriage and cutter assembly, with portions in cross-section and a portion of the structure removed to illustrate certain details thereof; 
           [0021]      FIG. 5  is a partial vertical cross-section of the structure depicted in  FIG. 4 , with portions removed in order to illustrate other details of the structure; 
           [0022]      FIG. 6  is a bottom perspective view of the cutter assembly; 
           [0023]      FIG. 7  is a perspective view of a knife clamp; 
           [0024]      FIG. 8  is a perspective view of a knife; 
           [0025]      FIG. 9  is a perspective view of a knife holder; 
           [0026]      FIG. 10  is a partial horizontal cross-section of a cutter assembly exemplifying the relationship of the elongated segments with respect to one another and to the center of the assembly; 
           [0027]      FIG. 11  is an enlarged partial horizontal cross-section of portions of the elongated segments and a portion of the carriage showing a product in the act of being cut into the lattice product of the present invention; 
           [0028]      FIG. 12  is a perspective view of a portion of the lattice-cut product of the present invention; 
           [0029]      FIG. 13  is an enlarged cross-section taken along line 13-13 of  FIG. 12 ; 
           [0030]      FIG. 14  is an enlarged cross-section taken along line 14-14 of  FIG. 12 ; 
           [0031]      FIG. 15  is a schematic end view of a cutting blade for making the lattice-cut product of  FIG. 12 ; and 
           [0032]      FIG. 16  is a flow diagram of the process steps involved in making a potato product according to the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0033]    Apparatus for making the lattice-cut product of the present invention is described in U.S. Pat. No. 3,139,130, the disclosure of which is hereby incorporated by reference herein. The apparatus may be used to slice substantially any firm food into a lattice configuration, but will be described herein in connection with cutting potatoes into corrugated or lattice-cut slices. 
         [0034]    Referring to  FIGS. 1-3 , the main components of an apparatus  10  for cutting potatoes into lattice-shaped slices generally include a motor  3 , a stationary cutter assembly  4  supported by a frame, and a carriage assembly  5  disposed in the cutter assembly and rotatable relative to same. A conveyor (not shown) may be employed to feed the potatoes into a hopper  7  above carriage assembly  5 . A pipe (not shown) may be located above apparatus  10  for continuously delivering a small stream of water into carriage  5  in order to free the carriage and the cutter assembly  4  from any accumulation of starch and promote the flow of the potato products therethrough. 
         [0035]    Motor  3  may be operatively connected to rotatable carriage  5  by a drive shaft  14  and a vertical shaft  15  geared to the drive shaft. One end of drive shaft  14  may be rotatably supported by roller bearing assembly  30  and may be provided with a relatively large pulley  16  having a belt thereon which is driven from a smaller pulley (not shown) carried by the shaft of motor  3 . The other end of drive shaft  14  may be rotatably supported by another roller bearing assembly  32 , and may include a small spiral bevel gear  17  which meshes with a larger bevel gear  18  keyed to the lower end of vertical shaft  15 . Vertical shaft  15  may be rotatably journaled at its lower end by roller bearing assembly  41  and at its upper end by roller bearing assembly  42 . The upper end of vertical shaft  15  may be provided with an annular head  19  on which the carriage  5  is detachably secured. 
         [0036]    The carriage  5  generally includes a vertically oriented receptacle  45  and four identical tubular guides  46  extending radially outward therefrom at substantially perpendicular angles to one another. Receptacle  45  includes a base wall  47  operatively connected to vertical shaft  15 , and four vertical side walls  48 . Receptacle  45  is open at its top for receiving potatoes from hopper  7  or by other means of introduction. A large circular opening  51  in each side wall  48  defines a passageway between receptacle  45  and the interior of a respective tubular guide  46 . 
         [0037]    Tubular guides  46  are mounted to receptacle  45  so as to be rotatable relative to the receptacle about their longitudinal axes. Each tubular guide  46  may be provided with a relatively large radial annular flange  65  with an annular portion  66  disposed at an oblique angle to the radial flange. The free edge of each portion  66  includes a plurality of teeth or serrations  67  which are adapted to engage a resilient ring  68  fixedly connected to the support structure of apparatus  10 . As a result, when carriage  5  is rotated about its vertical axis, the engagement of teeth  67  against resilient ring  68  causes the tubular guides  46  to rotate about their own axes. In a preferred arrangement, the rotation of tubular guides  46  will cause the potatoes therein to rotate by about 90° about their own axes for each quarter turn of carriage assembly  5 , as will be explained further below. 
         [0038]    Each tubular guide  46  is preferably cylindrical, and includes an annular V-shaped exterior groove  52  adjacent its inner end which serves as a track for receiving three identical roller assemblies  56  secured at equally spaced positions to each side wall of receptacle  45 . A plurality of circumferentially spaced longitudinally extending ridges  55  may be provided on the inner surface of each tubular guide  46  to assist in rolling or rotating the potatoes as they travel through the guide. 
         [0039]    The cutter assembly  4  may include four curved elongated segments  74 ,  75 ,  76  and  77 , each of which has an inner spheroidal surface  81 , an upper horizontal outer flange  82 , and a lower horizontal outer flange  84 . Each of segments  74 - 77  is mounted to an upper annular support  78  by a screw  79 , and to a lower annular support  71  by a pin  90  which is aligned with screw  79  so that each segment is able to pivot about a vertical axis. A curved cutting blade  88  is mounted to the free end of each segment, and the opposite end of each segment terminates in an edge  89 . The thickness of the slices to be cut may be adjusted by pivoting one of the elongated segments relative to the next adjacent elongated segment so as to adjust the distance between the cutting blade  88  on the one segment and the terminal edge  89  on the adjacent segment. Once properly adjusted, screws  80  may be tightened to selectively lock the elongated segments in place. 
         [0040]    Cutting blades  88  are clamped in place between a blade holder  96  and a clamp  104  mounted at the free end of each of elongated segments  74 - 77 . More particularly, cutting blades  88  are held in place between a corrugated portion  105  of blade holder  96  and a corrugated portion  109  of clamp  104 . In the assembled position, the corrugations of cutting blade  88  are nested or mated with the corrugated portions of the blade holder  96  and the corrugated portions of the clamp  104 , with the cutting edge  112  of the cutting blade protruding outwardly therefrom by a predetermined amount. This amount is fixed by a locating shoulder  106  formed in blade holder  96  at a preset distance from the free edge of corrugated portion  105 . Not only does shoulder  106  fix the amount of cutting blade  88  that protrudes from blade holder  96  and clamp  104 , but it also supports the cutting blade and prevents it from being pushed backward as the cutting blade slices through the potatoes. 
         [0041]    Referring to  FIG. 10 , the cutting edge  112  of each cutting blade  88  is located the same radial distance R1 from a point X1 constituting the longitudinal axis of the cutter assembly  4 . The terminal edges  89  of elongated segments  74 - 77  are also all located the same radial distance from point X1, but at a greater distance than R1 due to the fact that the elongated segments have been pivoted in a horizontal plane to provide a discharge passage between the terminal edge  89  of one segment and the cutting blade  88  carried by an adjacent segment. In other words, elongated segments  74 - 77  have been adjusted so that, for example, the radial distance R2 from a center X2 to the spheroidal surface  81  of segment  76  is the same as the radial distance R3 from a center X3 to the spheroidal surface  81  of segment  77 . Centers X2 and X3, as well as the centers for the radial distances to the spheroidal surfaces of segments  74  and  75 , are equally spaced concentrically about the longitudinal axis X1 of cutter assembly  4 . 
         [0042]    The use of apparatus  10  for cutting a potato  113  will now be described with reference to the figures. As an initial step, the potatoes may be washed and peeled, except for those products in which it is desirable for the skin to remain on the potatoes. The potatoes may then be preheated to a temperature between about 90° F. and about 145° F. in a water bath for a time sufficient to slightly soften the potatoes, typically between about 15 minutes and about 45 minutes. This softening facilitates the slicing process, making it easier to obtain full slices of potato. Without this softening step, the potatoes are quite hard and are prone to fracturing before a slice has been completed. 
         [0043]    After the preheating step, the potatoes may be fed into receptacle  45  from hopper  7  or any other feed mechanism. As apparatus  10  is operated, carriage  5  will rotate about its longitudinal axis, and each of tubular guides  46  will rotate about its respective longitudinal axis. The centrifugal force resulting from rotation of carriage  5  will automatically project the potatoes in receptacle  45  radially outward through one of the openings  51  in the receptacle and into the adjacent tubular guide  46 . The rotation of tubular guides  46  along with the longitudinally extending ridges  55  therein cause the potato  113  to rotate about its own axis as it is being forced radially outward against the spheroidal surfaces  81  and cutting blades  88  of cutter assembly  4 . As the cutting assembly  4  remains stationary, the rotation of the carriage assembly  5  will cause the tubular guide  46  to push a potato  113  therein toward and past the cutting blades  88 , whereby a slice will be cut from the potato as it passes each of the cutting blades. Moreover, the rotation of tubular guides  46  will cause potato  113  to rotate between slices so that the corrugations on one surface of a slice will be transverse to the corrugations on the other side of the slice. Preferably, potato  113  will rotate about 90° (or a multiple thereof) about its axis for each 90° rotation of carriage assembly  5 . In other words, potato  113  preferably will rotate about 90° between successive slices so that the corrugations on one surface of the potato slice will be substantially orthogonal to the corrugations on the opposite surface of the slice. 
         [0044]      FIG. 11  shows cutting blades  88  cutting a slice  114  from potato  113 . The slice has curved ridges  115  extending in a first direction on one side and curved ridges  116  extending in a second direction on its opposite side, the second direction being transverse to the first direction. Preferably, the first and second directions are substantially perpendicular to one another. More particularly, ridges  115  may have been formed as the cutting blade  88  on elongated segment  75  cut the potato  113 , and after the potato has rotatably slid against the spheroidal surface  81  of segment  75 , the cutting blade on the adjacent segment  76  cuts the potato to simultaneously form the ridges  116  on the severed potato slice  114  and the ridges  117  on the outer side of the remaining potato as indicated by the dotted lines. Thus, as the carriage  5  rotates relative to cutter assembly  4 , the potato  113  will be sliced by cutting blades  88  on successive segments  74 ,  75 ,  76  and  77  until the entire potato has been exhausted. 
         [0045]    Although the foregoing describes only a single potato  113  being rotated and cut within a guide tube  46 , it will be appreciated that, depending upon the size of the potatoes, two or more potatoes may reside in a guide tube and be simultaneously forced against and sliced by cutting assembly  4 . Moreover, it will be appreciated that, while one or more potatoes are being sliced by cutting assembly  4 , other potatoes may be lined up behind them in tubular guide  46  to be sliced in succession. 
         [0046]      FIG. 12  depicts a portion of the lattice-cut product produced by apparatus  10 . Lattice-cut potatoes according to the present invention are generally in the form of a slice  114  having an ellipsoid outer periphery which would depend, to a large extent, on the shape of the potato being sliced. Each ridge  115  on one surface of slice  114  has a longitudinal peak  119  with a radius of curvature R of about 0.100 inches. Similar ridges  116  with longitudinal peaks  121  having a radius of curvature of about 0.100 inches are on the opposite surface of slice  114 . A groove or channel  122  is formed between each pair of ridges  115 , and a similar groove or channel  124  is formed between each pair of ridges  116  so that each surface of slice  114  is provided with alternating ridges and grooves. 
         [0047]    The slices  114  may have a thickness from the peaks  119  on one surface of the slice to the peaks  121  on the other surface of the slice of between about 0.110 inches and about 0.350 inches measured in a direction substantially orthogonal to the first and second surfaces, with a thickness of about 0.220 inches being preferred. The thickness of the slice may be adjusted by adjusting the positions of elongated segments  74 - 77  of apparatus  10 . When segments  74 - 77  are adjusted to produce a slice of appropriate thickness, the cutting blades  88  will cut to a predetermined depth so that the grooves formed on one surface of the slice will intersect with the grooves formed on the other surface of the slice to produce a multiplicity of openings  120  extending through the slice. 
         [0048]    The lattice-cut potato products of the present invention produce a crispy outer surface and a creamy inner texture when cooked in warm air, such as in an oven, or when cooked by microwave. Without being held to any particular theory, it is believed that these desirable results are achieved as a result of the ratio of the total surface area of the potato slices to the mass of the potato in the slices. In other words, the combination of the ridges  115  and  116  on the potato slices, the grooves  122  and  124  on the potato slices, and the openings  120  extending through the potato slices provides each potato slice with a very large surface area. Controlling the maximum distance from any point in the interior of the potato slice to a point on the exterior surface will assure that any residual moisture in the potato has an opportunity to escape through the potato surface during cooking, thereby enabling the potato to cook evenly and completely while maintaining a crispy surface texture. Preferably, the maximum distance from a point in the interior of the potato slice to a point on the exterior surface of the potato slice is between about 0.055 inches and about 0.175 inches, with a maximum distance of about 0.110 inches being preferred. 
         [0049]    A schematic end view of a cutting blade  88  for producing a lattice-cut potato slice  114  as described above is shown in  FIG. 15 . The cutting blade has a generally sinusoidal configuration formed by alternating longitudinal ridges  200  and grooves  210  which extend substantially perpendicular to the cutting edge  112 . The ridges  200  and grooves  210  have a radius of curvature R of about 0.100 inches. The peak-to-peak thickness T p-p  between the ridges  200  on an inner side  220  of the blade and the ridges  200  on an outer side  230  of the blade is preferably between about 0.108 inches and about 0.118 inches, and the cycle length L p-p  between the peak of one ridge  200  and the peak of the next adjacent ridge on the same side of the blade is preferably between about 0.328 inches and about 0.380 inches. A peak-to-peak thickness of about 0.113 inches and a cycle length of about 0.345 inches are highly preferred. Blades with a T p-p  of about 0.113 inches and an L p-p  of between about 0.328 inches and about 0.380 inches produce an L p-p /T p-p  ratio of between about 2.90 and about 3.36. In preferred cutting blades, the range in peak-to-peak thickness may be greater when the L p-p /T p-p  ratio is within a narrower range. Therefore, for cutting blades in which the peak-to-peak thickness is between about 0.108 and about 0.118 inches, the L p-p /T p-p  ratio is preferably between about 3.00 and about 3.20. 
         [0050]    Following cutting, the shaped potato slices  114  undergo a series of process steps prior to packaging.  FIG. 16  depicts the entire process to which the potatoes may be subjected. Thus, after washing and (optionally) peeling at step  500 , preheating at step  510 , and slicing at step  520 , all of which have been described above, the shaped potato slices  114  may be blanched at step  530  using a conventional processing technique. Such technique may include immersing the potato slices  114  in a water bath heated to between about 150° F. and about 200° F. for between about 5 minutes and about 20 minutes. It will be appreciated that the blanching time and temperature will be at least partially dependent on such factors as the potato variety and the size of the potato slices  114 . Other blanching techniques may be used, such as deluge blanching, steam blanching and the like. 
         [0051]    As shown at step  540 , the blanched potato slices  114  may then be dipped in a solution containing about 0.5-1.5 wt % sodium acid pyrophosphate, 0-1 wt % dextrose, 0.5-1 wt % salt, and/or other ingredients as desired. The solution may be at a temperature of about 150° F., and the slices may be dipped for about 60 seconds. As is conventional in the art, the sodium acid pyrophosphate prevents nonenzymic oxidation of the potato slices; the dextrose facilitates browning on cooking; and the salt enhances the flavor of the final product. It will be appreciated by those skilled in the art that some of the foregoing ingredients may be omitted from the solution, or may be replaced by different ingredients that perform the same or similar functions. 
         [0052]    Following the dipping process, the potato slices  114  are dried at step  550 . Preferably, the drying step occurs in an elevated temperature environment, such as a forced air dryer. The elevated temperature may be between about 85° F. and about 120° F. for a period of about 10 minutes to about 14 minutes. 
         [0053]    The dried potato slices  114  are then parfried at step  560  to achieve a total solids content of between about 48 wt % and about 68 wt %. The temperature of the oil in the parfrying step is preferably between about 330° F. and about 400° F. Following parfrying, excess oil optionally may be removed from the surface of the potato slices using an Oil Miser® oil recovery system available from Reyco Systems, Inc., of Caldwell, Id. Such step ensures a uniform oil content among the potato slices. The potato slices may then be equilibrated at step  570 . Equilibration may take place at a temperature of between about 70° F. and about 110° F. for about 1 minute to remove residual heat and moisture from potato slices  114 . 
         [0054]    The equilibrated potato slices  114  may be frozen in a conventional manner at step  580 . Freezing may be effected by a spiral freezer or any other conventional freezing apparatus known in the art. The frozen potato slices may be packaged at step  590  and stored in freezers at step  600 . 
         [0055]    The final cooking of the potato slices may be performed by a customer in the foodservice trade or by a retail customer at step  610 . Cooking may be accomplished in a number of ways, but the preferred method does not involve frying in oil. In one cooking method, the frozen potato slices  114  may be spread on an oven-safe sheet or other container and baked in a hot air environment, such as an oven. In a preferred baking method, the potato slices may be heated in a conventional oven at between about 350° F. and about 450° F. for between about 2 minutes and about minutes. Cooking at about 425° F. for about 3.5 minutes is particularly preferred. Cooking may also take place in a convection oven. In such event, the cooking temperature may be about the same as in a conventional oven, but the cooking time may be between about 1 minute and about 4 minutes, with a cooking time of about 2.5 minutes being preferred. 
         [0056]    The frozen potato slices  114  may also be cooked using microwave energy. A microwave cooking process may include spreading about 4 oz. of the frozen potato slices  114  on a microwave-safe plate or other container, and subjecting the slices to 1000 watts of microwave energy for about 75 seconds. 
         [0057]    A still further cooking method may include a combination of hot air and microwave energy. This method may include heating the potato slices in a Turbochef® oven (available from Turbochef Technologies, Inc. of Carrollton, Tex.) at a temperature of about 1150° F. for between about 20 seconds and about 30 seconds using both hot air and microwave energy. 
         [0058]    While the foregoing process includes the step of freezing the potato slices prior to packaging, this step is not required. Thus, there may be applications in which the potato products are simply refrigerated after the equilibration step, and stored in a refrigerated state. Particularly for retail consumers, refrigerated products may convey the image of a fresher, healthier product. 
         [0059]    Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present application. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention.