Abstract:
A method of controlling the movement of snack food products being cooked continuously in a bath of hot cooking oil to the end of realizing a more uniform moisture content in the final product employs a plurality of segmented paddle wheels with blades to penetrate and agitate vigorously the product pack as the wheels are rotated in both directions. Also disclosed are a variety of segmented paddle wheel configurations and their functions of impeding and urging product flow during cooking.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention concerns cooking snack foods in a hot oil cooking bath in a continuous process and especially relates to controlling and agitating a pack of product during cooking so as to achieve better uniformity in product quality. 
       BACKGROUND OF THE INVENTION 
       [0002]    In the field of cooking snack foods in a continuous process it has become accepted to rely largely upon the velocity of the cooking oil in the fryer to propel the product through the fryer in the cooking operation. Energy in terms of both heat and velocity is supplied to the cooking oil as it is pumped from a sump in the fryer to a heat exchanger and then returned to the fryer usually at the start of the cooking path or also at locations along that path as needed. Configurations displaying this arrangement are shown in U.S. Pat. Nos. 5,580,598; 5,167,979 and 5,137,740 all of which are owned by the assignee of this invention. 
         [0003]    The term “snack food” as used in this disclosure shall be taken to include potato chips, corn and tortilla chips, pellet snacks and the like. In the case of cooking potato chips, raw potato slices are deposited from above into the oil bath of a continuous fryer in a substantial volume to eventually form into a pack. Initially there is a vigorous boil as the water carried on the slice surfaces as well as the moisture contained within the slices boils off. Rotating stirring means known in the field as “paddles”, as well as the cooking oil velocity, serve to urge the mass or pack of potato slices away from the slice inlet and downstream toward the product outlet thereby defining a cooking path. 
         [0004]    Uniformity of moisture content in a package of snack foods is a highly desired quality in that it assures the producer that his product, when packaged, will have a longer shelf life as well as good taste and bite when the package is opened and consumed. Assuming the overall goal product moisture content is, for example, 2% there invariably are deviations among items within the package and from package-to-package as well as among production runs. These variations in product moisture contents, in large part, can be attributed to uneven agitation of the product while being cooked. There a large portion of the product will be cooked evenly while a small portion will be under cooked or over cooked. When mixed together in the product packaging operation the resulting combination of proper cooked, under cooked and over cooked product there is created a non uniformity in product moisture content. For the producer the issue becomes how much non uniformity can be tolerated before “off taste” and shorter shelf life become paramount and waste follows. If the moisture content of every slice in the pack is held to a controlled level at a known location in the fryer, the result is very good uniform control over the finish frying stage of the product. Uniform control over the finish frying stage of the product means virtually every chip exits the fryer with the same moisture content. Uniform moisture content of the final product means that some chips are not produced with significantly lower moisture contents than other chips. Noteworthy is that the significantly lower moisture content chip is in danger of having significantly higher acrylamides because it finish fried at a lower moisture content. 
         [0005]    Prior art paddles for continuous fryers generally included a motor driven rotatable shaft mounted laterally across the fryer at one or more locations along its length. Arranged on the shaft were “blades” such as generally rectangular sheets of metal configured on the shaft to serve as an impeller. Such paddles, depending upon the direction of their rotational motion, acted to regulate, by somewhat blocking, product flow downstream against the velocity of the cooking oil. Being that the paddles and blades were mounted to extend into the product pack and for a small distance down into the bath of cooking oil, some product slices would work their way around or beneath the paddle blades and receive a shorter cooking time. The result was inconsistency in the product cook time, appearance and moisture content. 
         [0006]    The development of acrylamides in snack food containing starch has been noted and studied and may soon become a matter of governmental regulation. See: http://www.cfsan.fda.gov/˜dms/acrydata.html. Potato chips from a variety of well known producers and tested by the U.S. Food and Drug Administration were found to be in the range of a high of 1265 ppb (parts per billion) to a low of 20 ppb of acrylamide. Several animal tests have shown acrylamide to be a carcinogen, and a recent study conducted by the National Food Institute, Technical University of Denmark, has shown a positive association between acrylamide and breast cancer in humans. See: http://en.wikipedia.org/wiki/Acrylamide. Clearly established when frying carbohydrates in hot cooking oil is the link between product moisture content (around 5%) cooking time and temperature of the oil medium. The research teaches the shorter the cooking time when the product is at or below the critical moisture content, the less acrylamide the will be found in the oil cooked product. 
       SUMMARY OF THE INVENTION AND OBJECTS 
       [0007]    This invention promotes uniformity of product final moisture content and appearance while minimizing the time for development of acrylamides by providing rotatable, segmented paddle wheel assemblies arranged in a snack food fryer of the continuous cooking oil type wherein the paddle assemblies skirt the bottom of the fryer pan and are controllable to rotate in a variety of modes and speeds. The segmented paddle wheels are of various types including a double break finger type and a double break blade type in four arm and eight arm configurations. A plurality of the segmented paddle wheels arranged in the fryer control progression of the product through the fryer and vigorously mix the product within the pack so that the individual product pieces receive the same exposure to the hot cooking oil for the designed cook time. 
         [0008]    A general object of this invention is to create uniformity of final moisture content in a snack food product by ensuring at each stage of cooking that the product receive the same exposure to the cooking oil. 
         [0009]    Another object of this invention is to provide a method for cooking snack food products to a uniform designated moisture content thus insuring a uniformity in appearance and taste and a long shelf life. 
         [0010]    Still another object of this invention is to provide apparatus arrange to vigorously mix product while cooking as well as urging product to move at a designated rate through a snack food fryer. 
         [0011]    Yet another object in view of the prior object is to promote the cooking of a snack food with a desirably low acrylamide content. 
         [0012]    A further object is to provide a snack food fryer equipped with novel paddle wheel assemblies operable to aggressively and vigorously stir the product during cooking to the end of producing a product of uniform final cooked moisture content. 
         [0013]    These and other objects of the invention will become apparent from a consideration of the specification text when considered with the following drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  illustrates in a fragmentary elevation view of a continuous oil fryer having installed therein novel apparatus capable of performing the process of the present invention; 
           [0015]      FIG. 2  is a plan view of the apparatus of  FIG. 1 ; 
           [0016]      FIG. 3A  is an enlarged, perspective view of one version of an eight blade segmented paddle wheel assembly useful in the present invention; 
           [0017]      FIG. 3B  is a view on the scale of  FIG. 3A  showing the segmented paddle wheel of  FIG. 3A  and as shown on a smaller scale in  FIG. 1 ; 
           [0018]      FIG. 4  is a view like  FIG. 3A  showing another form of segmented paddle wheel, this having four blades each with a double break; 
           [0019]      FIG. 5  is a view like  FIG. 3A  showing still another form of segmented paddle wheel, this having four blades each having received a single break; 
           [0020]      FIG. 6  is an enlarged perspective view of yet another form of segmented paddle wheel, this having four double break fingers-like tines; 
           [0021]      FIG. 7  is a view like  FIG. 6  showing a further form of segmented paddle wheel, this having eight, double break finger-like tines; 
           [0022]      FIG. 8  is a view like  FIG. 4  but showing the reverse orientation of the paddle wheel; and 
           [0023]      FIG. 9  is an enlarged perspective view showing anther form of segmented paddle wheel with the blades extending from a rotatable drum. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    Referring to  FIGS. 1 and 2  of the drawings, an array of segmented product control paddles  10 , made in accordance with and operable within the principles of the present invention, is shown mounted in a fryer  11  of the continuous oil bath type. For reasons of brevity and conciseness, the fryer  11  is illustrated fragmentarily as a representative section but the operational hot cooking oil level  12  is indicated by a wavy line and a partial pack of snack food product  13  is depicted immersed in the oil  12  at only two locations. However, it shall be understood irrespective of this illustration that the fryer  11  is continuously charged with product  13  and cooks a pack of product throughout its full length in the normal cooking operation. To be noted from  FIG. 1  and also reflected in  FIGS. 3A and 3B  is that the inside bottom surface  14  of the fryer  11  and the lower most ones of the segmented paddle blades  16  are spaced relatively close together so that the blades  16  may sweep product fines along the bottom  14  as well as to preclude any but an insignificant quantity of the product  13  from moving beneath the rotating paddle blades. Well understood in the field of continuous fryers is that hot cooking oil is pumped into the fryer from a remote heat exchanger. The kinetic energy of the hot oil is the principal driving force serving to move the snack food product through the fryer  11 . The hot oil is introduced into the fryer pan, usually but not invariably, at the product feed end. 
         [0025]    Referring to  FIG. 2  is association with  FIG. 1 , the array of segmented product control paddles  10  comprise seven paddle wheels but this number is only for illustration while in an operating fryer  11  the number of segmented paddles may vary widely depending on the application (fryer size, product type or load and degree of agitation required) from as few as two to as many as twenty-two. A successful system for driving the segmented paddle wheels  10  is a sprocket and drive chain arrangement as indicated in  FIG. 2 . This arrangement includes a variable speed drive motor  17  coupled to a paddle wheel shaft  18 , the opposite end of which is equipped with a chain sprocket  19  upon which is reeved a drive chain  21  that runs to a similar sprocket and paddle wheel shaft on the next successive paddle wheel assembly. The other paddle wheel are similarly equipped so that the drive motor  17  may drive all the paddle wheels in the array. 
         [0026]    Alternatively, each individual segmented paddle wheel may be driven by a dedicated programmable drive motor (not shown) so that the rotational speeds of the segmented paddles wheel may be selected to suit widely varying conditions. In such a configuration certain of the segmented paddle wheels may rotate alternately clockwise and then counter-clockwise as indicated by the arrows  26  to achieve the objectives of controlling the forward movement of the product pack  13  against the forces of the cooking oil pumped into the fryer and being withdrawn at another location. This action of the segmented paddles  10  also facilitates agitation of the pack of product in a vigorous manner. Further it separates slices from each other thereby permitting the cooking oil to reach all surfaces of the individual product piece. 
         [0027]    Product agitation through rotation of the segmented paddles is vigorous given that the paddles may rotate in the range of ½ RPM to about 20 RPM. This assists in promoting even exposure of the product to the cooking oil throughout the pack with the expected result being a very even product moisture content at every point along the cooking path. We have been able to obtain repeatable final moisture results as intended and typical for different products. This in turn insures much better product shelf live when all of the product pieces within a package are at the same desired final moisture content. 
         [0028]      FIGS. 3A and 3B  display an eight blade, segmented paddle wheel  22  which is a more detailed representation of the paddle wheels  10  indicated in  FIGS. 1 and 2 . Each of the eight blades  23  is formed from gauge sheet metal which has been subjected to two treatments in a metal break, hence the term two break blades. The breaks or metal deformations of the blade are each at about an angle of 135 degrees so that the tip or end of the blade  23  is at about an angle of 90 degrees from its base attachment location on the shaft  18 . The space or slot  24  between adjacent blades  23  can be selected to be less that the apparent width of the general width of a product piece, ½ inches to 1¼ inches being satisfactory in discouraging product passing through the slot or gap  24  while permitting cooking oil flow there through. The breadth of the blades  23  while being effective in controlling and agitating the product pack also serves to restrain the tendency of the product to be carried freely by the flowing cooking oil. Hence it impedes and assists in regulation of product flow along the cooking path. 
         [0029]    As indicated by the arrows  26  in  FIGS. 3A &amp; 3B , the segmented paddle wheel  22  may be rotated in the clockwise and in the counterclockwise directions. If we assume looking at  FIG. 3B  that the snack food product flow in the fryer (the cooking path) is from left to right, rotation of the segmented paddle wheel  22  in a counter clock wise direction serves to resist motion of the product pack (not shown). When rotated in the clock wise direction, the paddle wheel  22  serves to grab into the product pack, stirring it and shifting some product into another position within the pack. Thus there are benefits in rotating the segmented paddle wheel in a continuous rotational pattern as well as rotating in an oscillating, first one way then the opposite way, pattern. The result is vigorous agitation and mixing of the snack food product within the pack during the cooking operation. 
         [0030]      FIGS. 4 and 5  are illustrations of a four blade segmented paddle wheel  27  which is a more detailed representation of another of the paddle wheels  10  indicated in  FIGS. 1 and 2 . Each of the four blades  28  is formed from gauge sheet metal which has been subjected to two treatments in a metal break, hence the term two break blades, all as described above in connection with blades  23 . The four blade configuration can serve the basic functions described above in connection with the paddled wheel  22  but in this case has a more aggressive action when digging into the flowing product pack taking action on a larger segment of product for mixing and agitation as the paddle wheel  27  rotates in the direction of product flow. 
         [0031]      FIGS. 6 and 7  show two other forms  29  and  31  of segmented paddle wheels, these with the presentation of finger-like blades or tines  32  extending radially from the central axle shaft  18  which is rotatable as indicated by the directional arrows  26 . Each of these tines or blades  32  were bent so as to extend into at least three planes transverse to the shaft  18 , having been subjected to at least three breaks during manufacture. When visualized in an end view it will be recognized that the tines or blades  32  take on a “S” curve configuration formed about the shaft  18 . An important characteristic and function of the of the finger-like blades is that they afford a vigorous agitation and mixing of the product pack promoting uniform contact with the cooking oil and eliminating clumps of stuck together product, an undesirable condition. 
         [0032]      FIG. 8  shows yet another form  33  of segmented paddle wheel which is a more detailed representation of the paddle wheels  10  indicated in  FIGS. 1 and 2 . 
         [0033]      FIG. 9  shows still another form  36  of segmented paddle wheel which is a more detailed representation of the paddle wheels  10  indicated in  FIGS. 1 and 2 . Here the blades  37  are mounted to extend from the surface a cylinder or drum  38 . The drum serves to push down on the product pack while the blades  37  “work the pack” in a vigorous agitated manner. 
         [0034]    It will be readily apparent that various modifications may be made to the structures and processes of this invention and still be within the scope of the present invention. In particular, in may be readily appreciated by those skilled in this art from the above description that the apparatus according to the invention provides for adjustability not only in the available rotational speeds of the segmented paddle wheels but in the rotational directions as well or in the oscillation rate of the paddle wheels. This feature of adjustability accords with better cooking times and the resulting uniformity of the final product moisture content. Accordingly, the scope of this invention shall only be limited within terms and spirit of the following claims.