GB2373988A - Rotary drum system for batter coating french fried potato strips - Google Patents

Abstract

A rotary drum system is provided for applying a batter coating to French fried potato strips prior to strip parfrying and freezing. The system comprises an elongated open-ended rotary drum 12 oriented for flow-through passage of cut potato strips upstream from a parfryer. The drum is rotatably driven about the center axis and includes internal baffles or vanes for tumbling the potato strips passed therethrough. A batter delivery manifold is mounted within the drum at a position above the center axis and includes multiple nozzles 56 for dripping or spraying a wet batter composition onto the tumbling potato strips. The batter flow rate through the manifold nozzles is adjustably correlated with the mass flow rate of potato strips through the rotary drum for thoroughly coating the potato strips, substantially without excess batter usage.

Description

ROTARY DRUM SYSTEM FOR BATTER COATING FRENCH FRIED POTATO STRIPS BACKGROUND OF THE INVENTION This invention relates generally to systems and methods for applying a viscous batter in a foods processing line for producing batter coated food products such as batter coated French fried potato strips and the like More particularly, this invention relates to an Improved batter coating apparatus and method designed for substantially completely and uniformly coating the food products with the batter composition, while substantially eliminating the excess batter usage and the attendant problems and disadvantages associated with batter reclamation and recycling.

Batter coated food products are generally known in the art and have enjoyed increasing consumer popularity in recent years For example, in one common form, a selected food product such as French fry potato strips is subjected to a batter coating step by immersion or spraying to encase or enrobe the food product within a liquid albeit relatively viscous batter containing a desired blend of Ingredients such as flavorings and seasonings and the like. The batter coated food products are then transported typically on a porous mesh conveyor to a cooking vessel such as a fryer for at least partially cooking the products prior to further processing steps such as freezing and final packaging. The cooking step, especially In the case of a fryer for parfrying batter coated French fried potatoes, solidifies and sets the batter adhering onto the external surfaces of the food products. The batter coating thus remains on the products at the time of reheating and/or finish cooking immediately prior to consumption.

During the production of batter coated food products as described above, significant excess quantities of the liquid-based batter are typically delivered to the product strips in order to achieve a substantially thorough coating of the exterior strip surfaces. The porous mesh conveyor is designed with a sufficient length to permit the excess batter portion to drip or fall from the strip products prior to delivery of the batter coated strips to the fryer. In this regard, it is highly desirable to separate this excess batter from the food products to reduce strip sticking or clumping prior to or within the fryer, and further to minimize fryer oil contamination and/or excess oil usage attributable to the production of fried batter crumbs.

A drip tray is normally positioned beneath the porous mesh conveyor to collect or reclaim this excess batter and thereby permit recycling thereof to the batter coating station. However, such batter reclamation and recycling can undesirably contribute to altered batter characteristics, such as shear thinning or shear thickening of the batter composition depending upon the specific batter ingredients. It can also permit loss of batter leavening due to exposure to elevated temperatures.

Batter recycling also reduces production control over batter freshness since specific batter portions can be recycled many times. As a result, In a typical recycled batter system, the overall quality and characteristics of the batter tend to degrade over time, whereby it is periodically necessary to discard the batter in favor of a fresh batter batch. Moreover, the Inclusion of the elongated porous mesh drip conveyor provides a batter coating system having a length that is generally incompatible with relatively simple and economical retrofit of a conventional non-batter French fry production line to produce batter coated products.

The present invention provides an improved apparatus and method for applying a liquid-based batter to food products such as French fried potato strips, wherein the batter IS applied to the potato strips as a relatively thin and substantially uniform surface coating, substantially without requiring delivery of excess batter to the strips. In addition, the present invention IS suitable for relatively simple and economical retrofit of a conventional non-batter French fry production line.

SUMMARY OF THE INVENTION In accordance with the invention, an improved system and method are provided for applying a liquid-based batter coating to the exterior surfaces of a food product in a foods processing line, particularly with respect to applying a batter coating to the exterior surfaces of French fried potato strips. The system and method comprise an elongated openended rotary drum for tumbling flow-through passage of pre-cut and blanched potato strips, in combination with a batter delivery manifold mounted within the drum for delivering the liquid-based batter to the potato strips. The potato strips are surface-coated with a relatively thin and substantially uniform batter film prior to exiting the rotary drum for conveyance to a subsequent processing station such as a hot oil fryer.

The batter delivery flow rate is closely controlled In relation to the mass flow rate of the potato strips through the rotary drum to substantially eliminate excess batter usage and attendant problems associated with batter reclamation and recycling.

In the preferred form, the elongated rotary drum is oriented generally horizontally with a center axis thereof extending with a selected and typically relatively small declination angle from an upstream to a downstream end thereof. The upstream end of the drum is aligned with input means for delivering the food product such as pre-cut and blanched potato strips into the hollow drum interior. A downstream end of the rotary drum is similarly aligned with output means such as a suitable conveyor for delivering the potato strips to subsequent processing equipment, such as a hot oil fryer for parfrying the batter coated potato strips prior to freezing and packaging steps The rotary drum is suitably mounted and

supported for rotation about said center axis, and a drive motor IS provided for rotatably driving the drum. The interior of the rotary drum IS lined with a plurality of elongated radially inwardly extending vanes or baffles shaped for tumbling the potato strips delivered to the drum, and for causing those potato strips to travel generally on a first-in, first-out basis from the input end to the output end for delivery to the output conveyor means.

The batter delivery manifold comprises an elongated carrier bar mounted within the interior of the rotary drum and extending generally longitudinally In parallel with the drum center axis. A plurality of nozzles are mounted along the length of the manifold conduit for delivering the liquid-based batter by dripping or spraying to the interior of the drum at a plurality of longitudinally spaced-apart locations therein. The drum is rotatably driven so that the vanes sweep the potato strips upwardly and then permit the strips to free-fall from the vanes back to the bottom of the drum interior. The carrier bar and the nozzles mounted thereon IS positioned within the drum interior to deliver the batter directly to the potato strips, preferably while those strips are in a free-fall attitude. Thus, the cut strips are directly coated with the batter by each of the multiple nozzles followed by gentle tumbling to achieve the desired relatively thin and substantially uniform batter film coating, substantially without excess batter usage.

Other features and advantages of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate the invention. In such drawings : FIGURE 1 is a schematic flow diagram illustrating a production line system and method for preparing batter coated food products such as French fried potato strips, including a rotary drum batter coating system in accordance with the present invention ; FIGURE 2 is a somewhat schematic side elevation view of the rotary drum batter coating system; FIGURE 3 is an enlarged sectional view of the rotary drum, taken generally on the line 3-3 of FIG. 2; and FIGURE 4 is an enlarged sectional view similar to FIG. 3, but illustrating an alternative configuration of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the exemplary drawings, an improved system and related method referred to generally in FIGURE 1 by the reference numeral 10 is provided for applying a liquid-based batter coating to the exterior surfaces of a food product, such as potato strips used in the production of French fried potato strips. The system and method 10 of the present invention generally include a rotary drum 12 for tumbled flow through passage of the potato strips, in combination with a batter delivery manifold 14 mounted within the rotary drum 12 for applying the batter to the tumbled strips at a controlled flow rate.

In the preferred production environment, the rotary drum system and method 10 are used in a production line of a potato processing plant for applying a substantially uniform and relatively thin film batter coating to the exterior surfaces of pre-cut and blanched potato strips prior to strip parfrying, freezing and packaging steps. In this regard, while the specific batter formulation and composition may vary, the rotary drum system and method of the present invention are particularly suited for applying thin film, so-called clear coat batters to the potato strips, such as the batter compositions disclosed in U. S. Patents 5, 059, 435; 5,141, 759,5, 648,110, 5,750, 168; 6,132, 785; and copending U. S Serial No. 09/441,112, all of which are incorporated by reference herein FIG. 1 is a schematic flow chart illustrating a typical production line process sequence for producing parfried and frozen French fried potato strips, modified to incorporate the rotary drum system and method of the present invention. More particularly, FIG 1 depicts the supply of raw potatoes such as Russet Burbank or other suitable potato variety to an initial wash step 16, followed by an optional peel step 18, and a cutting step 20 by which the raw potatoes are cut into elongated French fry strips of selected cross sectional size and shape. Thereafter, the cut potato strips are typically subjected to a blanch step 22 wherein the strips are partially cooked as by water or steam blanching, and further wherein this blanch step 22 commonly includes the presence of additives such as dextrose and/or sodium acid pyrophosphate (SAPP) in minor amounts for improved browning and color control during subsequent processing. The thus-blanched potato strips are then typically drained of excess water and may be subjected to a drying step 24 which may include exposure to ambient or heated air for a sufficient time to achieve a target strip weight loss such as on the order of about 15%. In some processing methods, a hydrocolloid surface coating may also be applied to the potato strips prior to batter coating, as described in U. S. Patents 5,885, 639 and 6,033, 697 which are incorporated by reference herein In general terms, the rotary drum batter coating system and method 10 is installed along the production line at a downstream end of the blanch and dry steps 22,24, and at an upstream end of subsequent processing steps including a parfry step 26, a freeze step 28, and a packaging step 30. Pre-cut, blanched and partially dried potato strips are conveyed to an input end 32 of the rotary drum 12 for application of the liquid-based batter via the batter delivery manifold 14. The potato strips are tumbled and conveyed through the drum 12 preferably in a continuous flow-through manner, and exit an output drum end 34 for conveyance to subsequent parfrying and further processing steps.

FIGS 2 and 3 illustrate the construction and operation of the rotary drum 12 in more detail. As shown, the rotary drum comprises an elongated hollow and open-ended structure supported by suitable bearings 36 (FIG 2) or the like for rotation about a center axis 38. The rotary drum 12 IS supported with its center axis 38 oriented at a selected declination angle relative to a horizontal plane, whereby the drum input end 32 is disposed at least slightly above the drum output end 34. This declination angle may be adJustably set to regulate the product throughput rate, and also to variably select the product residence time within the drum. A motor 40 is provided for rotatably driving the drum 12 about this center axis 38. The drum 12 may be constructed from a material such as stainless steel appropriate for use in a foods processing facility, and has a size and shape sufficient to accommodate a substantially product flowthrough capacity. In a preferred configuration for use in batter coating French fried potato strips, the drum 12 has a length of about 6-8 feet, and a diametric size of about 3-4 feet The motor 40 rotatably drives the drum 12 at a relatively moderate rotational speed on the order of about 6 rpm. With these parameters, the drum 12 has a substantial potato strips through-put capacity of about 4, 000-20, 000 pounds per hour The potato strips are delivered to the input end 32 of the rotary drum 12 by any suitable conveyance means, such as the illustrative input chute 42 shown in FIG. 2. The hollow interior of the drum 12 is lined by a plurality of radially inwardly extending vanes or baffles 44 (FIG. 3) which extend longitudinally for substantially the entire length of the drum interior These internal vanes 44 include leading end facets 45 which project radially inwardly from the adjacent interior drum surfaces 46 a sufficient distance and at a suitable angle to collect and sweep potato strips 48 upwardly from a lower region of the drum, and to carry the strips substantially to and preferably a short distance above a horizontal centerline 49 of the drum before allowing the strips 48 to slide off the leading end facets 45 and free-fall through the hollow drum interior back to a lower region of the drum In the preferred drum geometry, the leading end facets 45 of the vanes 44 project radially inwardly from the adjacent drum surfaces 46 by about 1-2 inches, and are oriented relative to the adjacent drum surface at an obtuse angle preferably on the order of about 135. This vane shape produces substantial free-fall of the strips 48 as viewed in FIG. 3, followed by substantial strip tumbling as the strips are collected and swept upwardly by another one of the vanes 44 followed again by free-fall back to the lower region of the drum.

The batter delivery manifold 14 comprises an elongated carrier bar 50 mounted directly within the interior of the hollow rotary drum 12 and extending longitudinally therein. FIG. 2 shows the manifold conduit 50 having an input end coupled to a supply conduit 51 which is connected In turn to a suitable and typically chilled batter supply 52. The manifold conduit 50 extends from the input end 32 of the drum to project longitudinally therein. A pump 54 may be mounted along the supply conduit 51 for delivering the batter from the supply 52 to the manifold conduit 50 at a selected flow rate and pressure. A plurality of nozzles 56 are mounted along the length of the carrier bar 50 within the drum interior for discharging the batter at a plurality of selected, spaced-apart locations FIG. 3 shows the specific and preferred mounting location of the carrier bar 50 within the drum 12 at a position disposed generally on the horizontal axis 49, and offset laterally a short distance to one side of a vertical centerline 58 through the drum 12.

In one preferred form of the invention, the liquid-based batter IS delivered to the carrier bar 50 and further to the multiple nozzles 56 for dripping the batter directly onto the potato strips 48, as those strips 48 free-fall from the vanes 44 in the course of the above described tumbling movement. That is, the drum 12 is rotatably driven in a direction indicated in FIGS. 2-3 by arrows 60 to carry the potato strips 48 upwardly from a central lower region of the drum Interior to a position generally at or slightly above the horizontal centerline 49, after which the strips 48 freefall through the hollow drum interior into the path of the batter dripped from the nozzles 56. With this construction, the batter is dripped directly onto the underlying strips which are then tumbled substantially continuously along the length of the drum 12. This direct batter application to the free-falling strips in combination with the tumbling action results in a substantially thorough, uniform thickness, and relatively thin film coating of the potato strips with the batter material.

FIG. 4 illustrates an alternative configuration of the invention, wherein the position of the carrier bar 50 is adjusted to accommodate spraying of the batter under pressure into the drum interior In this configuration, in comparison to the geometry depicted in FIG 3, the carrier bar 50 and the nozzles 56 mounted thereon are shifted to the left as viewed in FIG. 4, and the batter is spray-discharged under pressure from the nozzles 56 for direct application to the free-falling strips 48.

In accordance with one important aspect of the invention, the flow rate of the liquid-based batter delivered to the interior of the rotary drum 12 is closely regulated relative to the mass flow rate of the potato strips passing through the drum. More particularly, a controller 62 (FIG 2) is provided to adjust the batter delivery flow rate in accordance with the mass flow rate of the potato strips 48 so that supply of excess batter is avoided The controller 62 may be manually set according to the product mass flow rate, or it may comprise a computerized and automated station for regulating batter flow rate according to mass flow as measured, for example, by weighing apparatus (not shown) included along the upstream conveyance means 42 for delivering the potato strips to the rotary drum 12 With this arrangement, the batter supplied to the drum interior is substantially fully picked up by the potato strips, whereby batter reclamation and recycling considerations are eliminated The batter coated potato strips exit the rotary drum 12 on an output conveyor 64 or the like (FIG. 2) at the output end 34 of the drum This output conveyor 64 carries the coated strips 48 to the subsequent processing equipment, such as a parfry station 26 (FIG. 1) wherein the coated strips are parfried in hot oil. Importantly, by substantially eliminating excess batter exiting the rotary drum 12, problems associated with strip sticking on the output conveyor 64 and/or during parfrying are substantially reduced The coated and parfried potato strips are transferred from the parfry station 26 for subsequent processing such as freezing 28, packaging 30, followed by appropriate shipment or storage.

The rotary drum batter coating system and method of the present invention beneficially reduces and substantially eliminates the usage of excess batter in the French fry production line, since all of the batter delivered to the rotary drum IS used to coat the potato strips. The rotary drum tumbling action insures that the strips are substantially completely surface-coated with the desired uniform and relatively thin batter film. Since no portion of the batter is reclaimed or recycled, there is no need for close monitoring of batter characteristics and quality as required in prior systems utilizing recycled batter constituents. Moreover, the overall size of the rotary drum system is relatively compact, and thus may conveniently and economically be incorporated or retrofit into an existing French fry potato strip production line, in comparison with prior batter application systems requiring porous mesh drip conveyors of extended length for catching and recycling excess batter.

A variety of modifications and improvements in and to the rotary drum batter coating system and method of the present invention will be apparent to those persons skilled in the art. As one example, the batter deliver nozzles 56 may be charged electrically, and the structure of the rotary drum 12 oppositely charged, to provide electrostatic deposition of the batter onto the tumbled potato strips 48. Accordingly, no limitation on the invention is intended by way of the foregoing description and accompanying drawings, except as set forth In the appended claims.

Claims (19)

CLAIMS:

1. A system for batter coating a food product, comprising' an elongated rotary drum defining an input end and an output end, said rotary drum being supported with a center axis thereof oriented at a selected declination angle relative to a horizontal plane ; a plurality of elongated vanes lining the interior of said drum and projecting generally radially inwardly therefrom, said vanes engaging the food product upon drum rotation for tumbling the food product and for sweeping the food product upwardly within said drum, said vanes being configured to permit the upwardly swept food product to free fall therefrom within said drum; means for rotatably driving said drum about said center axis thereof at a controlled rotational speed; and batter delivery means within said drum, said batter delivery means including a manifold conduit extending generally longitudinally within said drum and having a plurality of nozzles mounted along the length thereof for delivering batter to the interior of said drum for contacting the food product during free fall thereof, whereby the combined tumbling and free fall action of the food product within said drum results in a substantially uniform and thorough batter coating of the food product

2. The system of claim 1 further including means for delivering a flow of the food product into said drum via said input end thereof ; and means for conveying the food product from said drum output end to a subsequent food processing station.

3. The system of claim 1 wherein the food product comprises potato strips.

4 The system of claim 1 wherein said selected declination angle IS adjustable to variably select the mass flow rate and residence time of the food product through said rotary drum.

5. The system of claim 1 wherein each of said vanes extends longitudinally within said drum substantially the length of said drum

6. The system of claim 5 wherein each of said vanes defines a leading end facet relative to the direction of drum rotation for sweeping the food product upwardly within said drum to a position at least slightly above a horizontal centerline of said drum before allowing the food product to free fall therefrom.

7. The system of claim 6 wherein said leading end facet of each of said vanes is angularly oriented at an obtuse angle of about 135 < w relatively to an adjacent interior surface of said drum.

8. The system of claim 1 further including pump means for pumping batter through said manifold conduit to said nozzles.

9. The system of claim 8 wherein said pump means delivers the batter through said manifold conduit for substantial drip-flow passage through said nozzles

10. The system of claim 8 wherein said pump means delivers the batter through said manifold conduit for spray-flow passage through said nozzles.

11. The system of claim 8 further including controller means for controlling said pump to regulate the rate of batter flow through said manifold conduit to said nozzles in relation to the mass flow rate of the food product through said drum to substantially eliminate excess batter exiting said drum.

12. The system of claim 1 further including controller means for regulating the rate of batter flow through said manifold conduit to said nozzles in relation to the mass flow rate of the food product through said drum to substantially eliminate excess batter exiting said drum

13. A method for applying a batter coating to a food product, said method comprising the steps of: passing the food product through an elongated rotary drum supported with a center axis thereof oriented at a selected declination angle relative to a horizontal plane, and having a plurality of elongated vanes lining the interior of said drum and projecting generally radially inwardly therefrom to engage the food product upon drum rotation for tumbling the food product within said drum and for sweeping the food product upwardly within said drum, and said vanes being configured to permit the upwardly swept food product to free fall therefrom within said drum; rotatably driving said drum about said center axis thereof at a controlled rotational speed; and delivering batter through a plurality of nozzles mounted at longitudinally spaced locations within the drum into contact with the free failing food product, whereby the combined tumbling and free fall action of the food product within said drum results in a substantially uniform and thorough batter coating of the food product.

14. The method of claim 13 wherein the food product comprises potato strips.

15. The method of claim 13 further Including the step of adjustably varying said selected declination angle to variably select the mass flow rate and residence time of the food product through said rotary drum

16. The method of claim 13 further including the step of pumping the batter to said nozzles.

17 The method of claim 13 further including the step of regulating the rate of batter flow to said nozzles in relation to the mass flow rate of the food product through said drum to substantially eliminate excess batter exiting said drum

18. A system according to claim 1 and substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

19. A method according to claim 13 and substantially as hereinbefore described with reference to the accompanying drawings.