Apparatus for Making a Complexly Patterned Extrudate

The present invention comprises apparatus and methods for making complexly patterned multicolored extruded food products. More particularly, the present invention relates to apparatus and methods for reducing a large cross sectional area complexly patterned food extrudate to a smaller area while maintaining the complex pattern.

Food products such as Ready-To-Eat ("R-T-E") cereals and snack products vary widely in composition, shape, color, flavor, texture, etc. Such products can include both puffed and unpuffed varieties. One attractive feature is their appearance which can include specific attributes such as shape and coloration. Especially attractive are products having a complex but organized pattern of coloration, shape and/or complex shape.

A wide variety of techniques are known to provide complexly shaped products such as rings, stars, letters, figures, etc. Problems generally include how to provide consistently the desired degree of shape detail or resolution in the finished pieces. Similarly, for colored products, a problem is how to consistently provide a fine level of detail. This problem of imparting a fine level of detail is particularly difficult in the provision of complexly patterned R-T-E cereals due to their generally smaller size. The problem is even more severe for puffed R-T-E cereal products due to the very tiny size of the pellets that are expanded to form the finished products. Of course, the pellets must contain and retain the complex pattern.

In particular, it would be desirable to prepare puffed R-T-E cereals having a shape and color pattern reminiscent of various sports balls such as baseballs, footballs, basketballs and soccer balls, such as are disclosed in 1) U.S. Design patent application Ser. No. 014,233, filed Oct. 18, 1993 by Laughlin et al. entitled Food Product Piece, 2) U.S. Design patent application Ser. No. 014,068, filed Oct. 12, 1993 by Laughlin entitled Food Product Piece, 3) U.S. Design patent application Ser. No. 014,474, filed Oct. 22, 1993 by Laughlin entitled Food Product Piece now U.S. Pat. No. Des. 368,791 issued Apr. 16, 1996, and 4) U.S. Design patent application Ser. No. 014,069, filed Oct. 12, 1993 by Laughlin entitled Food Product Piece now U.S. Pat. No. Des 372,352, respectively, each of which are incorporated herein by reference. Such products are characterized in part by high degrees of resolution such as by line features (such as to indicate traditional sticking patterns) 1 mm> in thickness and even 0.5 mm>. Providing a cereal pellet which upon puffing provides a puffed R-T-E cereal exhibiting such a fineness of detail is a difficult problem to overcome.

Line colored or externally striped food products such as R-T-E cereals as well as apparatus and methods for their preparation are described in U.S. Pat. No. 2,858,217 entitled Cereal Product With Striped Effect and Method of Making Same (issued Oct. 28, 1958 to J. O. Benson) and which is incorporated herein by reference. The '217 patent describes an extrudate extruder having a color injecting die insert for making a complexly patterned extrudate. However, the extrudate is directly extruded without any reduction in its cross sectional area. Also, the method appears to be limited to producing only flakes in a simple pattern of generally parallel more or less straight lines. The method is not capable of generating a direct expanded cereal or snack (i.e., expanded directly from the extruder) having a line detail of such a degree of fineness.

An improvement or modification in the technique for providing a line colored cereal based snack piece is described in U.S. Pat. No. 3,447,931 (issued Jun. 3, 1969 also to Benson et al.) entitled Process For Preparing A Puffed, Concave Shaped Cereal Product. More particularly, the '931 patent describes a process for making a cup flower shaped R-T-E cereal piece having a complex line pattern. The process involves extruding a plurality of rope dough filaments which are pressed together to form a column or rope without a material decrease in the cross section which is then combined under conditions such that no puffing occurs. The composite strand of compressed filaments is then cut into wafers and which are subsequently heat puffed. While useful, the process appears to be limited to producing only the "flower bloom" shape. Also, the pieces prepared are of a larger snack piece size rather than the relatively smaller pieces characteristic of R-T-E cereals.

The present invention provides an improvement in apparatus and methods for preparing food products characterized by at least two colors in an organized pattern. In particular, the present invention provides an improvement in the degree of fineness level of color detail (1 mm>) even on food products such as pellets for puffed R-T-E cereals that are very small (e.g., 3 to 6 mm) in diameter.

FIG. 1 is an end view partially cut away of the die face of a food cooker extruder showing a plurality of exit ports.

FIG. 2 is a sectional view greatly cut away of a reduction passageway of the present invention taken along lines 2--2 of FIG. 1.

FIG. 3 shows an enlarged sectional view of a die insert for making an enlarged complexly shaped dough taken along lines 3--3 of FIG. 2.

FIG. 4 is an enlarged sectional view of a die insert showing the channels for the food color flow taken along lines 4--4 of FIG. 3.

FIG. 5 is an enlarged sectional view of the die insert taken along lines 5--5 of FIG. 4 in an upstream orientation.

FIG. 6 is an enlarged sectional view of the die insert taken along lines 5--5 of FIG. 4 similar to FIG. 5 but showing a downstream orientation.

FIG. 7 is an enlarged plan view of a finished puffed complexly patterned R-T-E cereal piece prepared using the present methods and apparatus.

FIG. 8 is an enlarged sectional view of the R-T-E cereal piece taken along lines 8--8 of FIG. 7 showing the concave shape of the cereal piece.

Where used in the various figures of the drawing, the same numerals designate the same or similar parts. Furthermore, when the terms "top," "bottom," "first," "second," "upper," "lower," "height," "width," "length," "end," "side," "horizontal," "vertical," and similar terms are used herein, it should be understood that these terms have reference only to the structure shown in the drawing and are utilized only to facilitate describing the invention.

Referring now to the drawing and briefly in particular to FIG. 1, there is shown an apparatus for preparing a complexly patterned cereal dough piece according to the preferred teachings of the present invention that is generally designated 10. In the most preferred form, apparatus 10 generally includes a means for providing at least one extrudable food product or cooked cereal dough such as a cooker extruder 12 as seen in FIG. 1. Extruder 12 is seen to have at least one, and more preferably a plurality of exit, ports or orifices 13 each for extruding of a complexly patterned cooked cereal dough of the present invention (not shown) or other extrudable food product.

While a cooker extruder is the preferred equipment to provide the extrudable food, other conventional equipment and techniques can also be employed. For example, a batch cooker or semi-continuous cooker for cooking the ingredients in bulk can be equipped with dough forming and conveying extruder element. In other embodiments, e.g., a low moisture fruit paste, a simple screw conveyor can be employed. While in the present description particular reference is made to the provision of complexly patterned farinaceous materials such as R-T-E cereals and snack products, the skilled artisan will appreciate that the apparatus and techniques can be employed with a wide variety of extrudable food products, especially such plastic foods as low moisture fruit products.

Now referring to FIG. 2, the cooker extruder 12 provides the cooked cereal dough in quantity which can supply one or preferably, especially in commercial applications, a plurality of passageways 14, each leading to an exit port 13. In highly preferred embodiments, the apparatus 10 can additionally include a means for adjusting the cooked cereal dough flow rate and pressure such as the adjustably retractable dough flow adjuster plug 16 depicted. Such a flow rate adjustment means is particularly useful when, as in the embodiment depicted, the extruder supplies a large number of extrudate orifices. Absent such a flow rate adjustment means, the particular extrudate characteristics (e.g., pressure, mass flow) from each of so many orifices are difficult to control since the length of passageway 14 from the central supply can vary.

The flow adjuster plug 16 can include a rod or bolt 80 having threads 82 at its outer end 84 and a smooth portion 86 at its inner end 88. The plug further includes a means for sealing against dough leaking from the extruder such as at least a first "O" ring 90, 91 inset into a receiving peripheral seal groove 92, 93 respectively. The plug 16 can further include lock nut 94 which can be tightened against block 96 to secure the plug against movement such as caused by the extruder's vibration. The length of the plug and threading is adjusted so that when fully extended into passageway 14, the plug 16 will not choke off dough flow so as to minimize dough buildup upstream of the plug 16. In the preferred form, the length of the plug extending into passageway 14 when stopped is less than 90.degree. of the width of passageway 14. Dough buildup can lead to dough hardening and plugging downstream.

Other dough flow adjustment devices can be used with or in substitution for the preferred flow adjuster plug 16 herein if 1) positioned upstream of the die insert 20, and 2) do not increase the likelihood of downstream plugging.

The apparatus 10 further essentially includes at least one food color supply 18 which can supply a flowable colored food material such as food color liquid (whether oil or preferably water based). The color supply 18 is in fluid communication with and the apparatus 10 further includes a means for mixing or forming the food color liquid and extrudable food product into a complexly patterned food extrudate such as a greatly enlarged (relative to the exit orifice) pattern forming die insert 20 depicted. In the preferred embodiment, the passageway 14 can include a first flared or divergent portion 21 immediately upstream of the die insert 20 to widen the passageway 14 to an equal diameter to the die insert 20 as well as a second convergent flared portion 22 downstream. In the drawing, the passageway 14 and other constituent elements are depicted in close to actual size. Thus, the diameter of the die insert depicted 20 is about 30 mm and is positioned within a slightly enlarged portion 24 of passageway 14. As a result, the diameter of the complexly patterned dough extrudate as it exits the die insert 20 will have an enlarged initial diameter about 30 mm. Of course, other sizes for the die insert 20 can be used (e.g., 15 to 100 mm).

In FIG. 2, it can be seen that the complexly patterned dough extrudate so formed then moves through by pressure flow and apparatus 10 further includes a means for reducing the cross sectional area of the complexly patterned food extrudate while maintaining the pattern such as a reducing or necking passageway 25 depicted. The reducing passageway 25 can be fabricated from a single piece having, for example, a frusto conical bore or, as depicted, with a plurality of individual pieces such as the first, second and third pieces 26, 28 and 30, respectively, depicted. Individual pieces can be more easily cleaned. Also, the convergence angle and other attributes, e.g., internal surface, can be adjusted as needed (e.g., smoothness, anti-stick surface) to accommodate differences in the extrudate characteristics of different food products. In FIG. 2, it is seen that the passageway 14 has an initial relatively larger diameter 34 and a final relatively smaller or exit diameter 36 at the exit port 13. Moreover, while the passageway 14 is depicted as having a circular cross sectional area, in other embodiments the passageway 14 can be fabricated with a more complex pattern or peripheral configuration to define or define in part the exterior shape or configuration of the finished piece, including both regular shapes (e.g., stars, rings, ovoids, geometric shapes) as well as irregular shapes (e.g., animals, objects such as trees, cars, etc.). Furthermore, the passageway 14 can be fabricated with an interior surface of desired characteristics, e.g., polished or Teflon or other non-sticking surface, such as to provide decreased friction to facilitate retention of the complex pattern or to reduce the pattern's deformation. Especially desirable is an ovoid cross section for the passageway for preparation of an American style football or a rugby ball.

An important feature of the present invention is the convergence angle of the reducing passageway 25. It has been found important to maintain an average convergence or confinement angle of 5.degree. to 45.degree. , preferably 5.degree. to 20.degree. , and most preferably 10.degree. to 15.degree. in order to maintain the pattern while the cross sectional area is reduced. By "average convergence" is meant the angle formed from the diameter of the die insert 20 to the diameter 36 of exit port 13 over the length of the reducing passageway 25. As depicted, with passageway pieces 26, 28, and 30, some pieces, e.g., 26 and 30 have a sharper convergence angle while piece 28 has a shallower angle. Internal obstructions (e.g., shoulders) are to be avoided so as to provide a continuous passageway to minimize disrupting the complex pattern formed in the dough. FIG. 2 shows that the exit orifice diameter 36 is about 3 mm. Since the passageway 14 can have a complex cross sectional shape as described above, the extent of reduction of the pattern is more aptly characterized in terms of cross sectional area reduction rather than more simply a reduction in diameter. Thus the degree of reduction of cross sectional area in the illustrated embodiment is about 100:1. Of course, for other embodiments (e.g., for larger snack pieces), the extent of cross section reduction can be as little as 25:1. The exit orifice diameter 36 for a snack product can be correspondingly larger, e.g., 5 to 15 mm.

Surprisingly, such a shallow convergence angle allows for a reduction in cross sectional areas of at least 50:1 and even about 100:1 while maintaining a fine level of detail in the complex pattern. Thus, a complex shape can be imparted to a larger dough face or cross section and then reduced to the much smaller desired finish cross sectional area. This arrangement allows for the fabrication of a relatively large die insert to impart the complex pattern. Fabricating a small die insert to impart the desired degree of detail for the final exit diameter while possible on a development scale extruder is not commercially practical due in part to plugging or fouling of the die insert 20. The provision of a reducing passageway 25 having the requisite convergence angle allows for the provision of three dimensional shapes to be produced with a fine level of color detail. Moreover, the finished pieces are characterized by a color through the entire piece as compared to only topical coloration.

Also, it is seen that the mixing is not immediately proximate the discharge port but distanced therefrom. This allows for the dough to modestly "set" so as to assist in maintaining the complex shape.

Reference is now made to FIG. 3 which shows an enlarged cross section of the pattern forming die insert 20. As can be seen, this particular die insert can be used to fabricate a bicolored food piece 40 as seen in FIG. 7 having a swirl or spiral pattern. However, other pattern forming die inserts can be substituted therefor which, for example, can impart the line pattern for products reminiscent of soccer balls, basketballs, baseballs and other sports objects.

The die insert 20 includes a means for imparting at least one, and more desirably a plurality of, dough interstitial gaps such as a plurality of dough dividing passageways such as passageways 44, 45, and 46 respectively formed by die dividing members. The die insert 20 can further include a means for injecting a food color or second colored dough into the interstitial dough gaps such as a plurality or array of evenly spaced food color injection ports 48 fed by a fluid supplying passageway 50 therethrough. The extrudable food product itself may be colored. The color supply 18 may supply a different color or the same color having a darker or lighter hue. Specifically, the food color passageways 50 are supplied with the food liquid from one or more food color supply ports such as ports 52, 54, and 56, respectively in the die dividing members. Of course, when the second or colored material is a food product such as a second dough or fruit paste, the passageways and injection ports can be enlarged to reduce friction and the potential for blockage.

Referring now briefly to FIG. 4, it can be seen that the die insert 20 can further include a color fluid supply reservoir 58 supplied by the color supply 18 and which is in fluid communication with or supplies food color supply ports 52, 54, and 56. The die insert 20 can further include a means for sealing the color fluid supply reservoir 58 against premature admixture with dough such as "O" rings 60 and 62 depicted.

Reference is now briefly made to FIG. 5 which shows the upstream face 64 of the die insert 22. FIG. 5 shows that the upstream face 64 for this particular die insert contains no color supply discharge ports and that the discharge of color is preferably in a downstream direction.

Reference is now made briefly to FIG. 6 wherein the relationship between the supply inlet ports, 52, 54, and 56 supply passageways 50 and color discharge ports 48 can be most simply seen.

Reference now is next briefly made to FIGS. 7 and 8 which show that the food piece 40 can have a cupped shape and that the coloration can extend throughout the body of the piece. The piece 40 depicted is a puffed R-T-E cereal piece prepared by direct expansion from the extruder having a finished diameter of about 70 mm.

In the present invention, the complexly patterned dough of reduced cross sectional diameter is extruded through the reduced diameter exit orifice 36 (e.g., about 3 mm). Thereafter, the extrudate is face cut in a conventional manner to form individual pieces such as with one or more rotating knives. Depending upon the conditions of the extrudate, an unpuffed pellet piece can be formed for subsequent puffing, or, alternatively, and preferably herein, a directly expanded finished puffed piece is formed. The finished food piece whether subsequently puffed or puffed by direct expansion upon exiting the exit orifice 13 is essentially characterized by exhibiting a high resolution or fine degree of color detail. The detail can include surface line coloration of as thin as about 0.5 mm in the puffed product. In certain embodiments, the interior is also bicolored or multicolored as well as having topical or surface coloration.

The extrudable food can comprise a wide variety of conventional food types and in particular can include a fruit paste, potato dough (e.g., for a fabricated chip) or a cooked cereal dough. The cooked cereal dough can be for either R-T-E cereals (whether puffed or unpuffed), snack products, baked goods, or pastas. Especially desirable are cooked cereal doughs for puffed R-T-E cereals. Puffed food products such as snacks can be prepared by hot air puffing, deep fat frying, gun puffing or microwave (especially high intensity, e.g., >100 V/cm field strength). Product puffed without deep fat frying can have oil added to the composition or have a topical oil application. R-T-E cereals can have a sugar coating. Puffed food pieces of the product base (i.e., prior to or without oil or sugar) can have a density of about 0.1 to 0.5 g/cc. The colored portion forms a line or a plane through the body of the food piece. "Highly complex" food products are characterized as having a plurality of colored features at least two of which (e.g., two planes or a line and a plane) intersect within the body of the food piece.

While in the present invention, the particular die insert 20 depicted is designed to admix a liquid food color into a cooked cereal dough so as to provide line coloration of extremely fine detail, the die insert 20 can be modified (e.g., such as by enlargement of ports 52, 54, and 56 fluid passageways 50 and discharge ports 48) to admix two or more cooked doughs or other flowable colored food materials, especially liquefied fats (e.g., chocolate, cheese), or fruit paste.

Also, while the particular die insert 20 depicted is designed to provide the swirled finished product depicted, other die inserts can be interchanged to provide the line coloration detail to provide the particular desired end products such as the various sports balls (e.g., soccer, baseball, basketball, American football) referenced above.

It will be appreciated that for those embodiments that are extruded without direct expansion or puffing upon extrusion that lines having a detail of about 0.1 mm in width can be obtained. Upon subsequent expansion (e.g., deep fat frying, gun puffing, fluidized bed puffing, radiant heat puffing or other puffing methods), puffed pieces will of course expand causing an increase in the width of the line. These enlarged lines (i.e., 0.5 mm>), however, are nonetheless thinner than lines obtainable by any other known method. If desired, thicker lines (e.g., about 3 mm) can also be formed.