Method and apparatus for oil removal from food surface

A method and apparatus for oil removal from food surfaces is shown. An air flow chamber directs air flow around a food product surface and contains the removed oil.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application represents a National Stage application of PCT/US2013/067923 entitled “Oil Removal From Food Surface” filed Nov. 1, 2013, pending.

BACKGROUND

When food products are cooked in hot oil, a substantial amount of oil adheres to the product surface after being removed from the hot cooking oil bath. This residue oil will either drip off the food surface or be absorbed into the food product surface the as it is transported to the next processing step for the just fried food product. Controlling the removal and capture of this residue oil is a challenge.

SUMMARY

The present disclosure relates to oil removal from food surfaces, in particular the present disclosure relates to the controlled removal of oil food surfaces and controlled capture of this oil.

In one illustrative embodiment, a method of removing oil from a food surface includes placing a food article within an air flow chamber. The air flow chamber has an inlet air expansion zone and an opposing outlet air contraction zone and the food article is within a product zone separating the inlet air expansion zone and the opposing outlet air contraction zone. Air flows from the inlet air expansion zone to the opposing outlet air contraction zone to form an air flow. The product zone has a pressure that is less than or equal to an ambient pressure outside the air flow chamber. Oil is removed from the food surface with the air flow.

In another illustrative embodiment, an apparatus for removing oil from a food surface includes an air flow chamber and a food product conveyor for moving food product through the product zone in a direction orthogonal to an air flow direction in the air flow chamber. The air flow chamber has an inlet air expansion zone and an opposing outlet air contraction zone and a product zone separating the inlet air expansion zone and the opposing outlet air contraction zone. The air flow chamber is configured to provide laminar air flow within the product zone.

DETAILED DESCRIPTION

The phrase “laminar air flow” refers to air (or fluid) flowing in parallel layers, without disruption between the layers. Laminar flow in a pipe is usually defined as having a Reynolds number of 2300 or less or 2000 or less.

The terms “upstream” and “downstream” refer to relative positions of elements of the flow chamber described in relation to the direction of air flow as it is drawn from the air chamber inlet and through the product zone to the air chamber outlet.

The present disclosure relates to oil removal from food surfaces, in particular the present disclosure relates to the controlled removal of oil food surfaces and controlled capture of this oil. An air flow chamber has an inlet air expansion zone and an opposing outlet air contraction zone and the food article is within a product zone separating the inlet air expansion zone and the opposing outlet air contraction zone. Air flows from the inlet air expansion zone to the opposing outlet air contraction zone to form an air flow. The product zone has a pressure that is less than or equal to an ambient pressure outside the air flow chamber. Oil is removed from the food surface with the air flow. The amount of turbulence, or lack thereof, of the air flow incident on the food product can be determined to increase or decrease the rate of residue oil removal from the food product surface. In many embodiments the air flow incident on the food product surface is laminar air flow. Laminar air flow has been found to increase the rate of residue oil removal from the food product surface. In some embodiments, air flow diverter elements can modify the air flow incident on specific food surfaces so that an amount of oil removal can be differential along the food product surface. While the present disclosure is not so limited, an appreciation of various aspects of the disclosure will be gained through a discussion of the examples provided below.

FIG. 1is a perspective side view of an illustrative air flow chamber10for oil removal from food surfaces25.FIG. 2is a cross-sectional view of the illustrative air flow chamber10ofFIG. 1. A substantial amount of the residue oil on the food product surface is removed or selectively removed as the food product is transported through the air flow chamber10. This removed residue oil is thus contained and collected within the apparatus for oil removal from food surfaces.

The apparatus for oil removal from food surfaces includes an air flow chamber10disposed between an air inlet12and an opposing air outlet14. The air flow chamber10includes an inlet air expansion zone16and an opposing outlet air contraction zone18and a product zone17separating the inlet air expansion zone16and the opposing outlet air contraction zone18. The air flow chamber10is configured to provide a specified level of turbulent or laminar air flow within the product zone17(as illustrated by the directions of the arrows within the inlet air expansion zone16and an opposing outlet air contraction zone18). A food product conveyor20is disposed through the air flow chamber10. The food product conveyor20is disposed through the product zone17. The food product conveyor20moves or conveys food product25through the product zone17in a direction orthogonal to an air flow direction (as illustrated by the directions of the arrows parallel with the food product conveyor20).

The inlet air expansion zone16is bounded on all sides by suitable ducting material and directs and expands the air flow area from the air inlet12area to the product zone17area. In many embodiments this area expansion is a smooth transition from the air inlet12area to the product zone17area. In some embodiments the air inlet12area is a circular or oval cross-sectional shape and the product zone17area is a rectangular or extended oval cross-sectional shape.

The outlet air contraction zone18is bounded on all sides by suitable ducting material and directs and contracts the air flow area from the product zone17area to the air outlet14area. In many embodiments this area contracts is a smooth transition from the product zone17area to the air outlet14area. In some embodiments the air outlet12area is a circular or oval cross-sectional shape and the product zone17area is a rectangular or extended oval cross-sectional shape.

The product zone17is bounded on two sides by opposing side walls15,19and opposing open ends22,24that are perpendicular to the opposing side walls15,19. A food product conveyor20extends through the product zone17and out the open ends22,24. The product zone17area is a rectangular or extended oval cross-sectional shape.

In many embodiments, the air flow chamber10is configured to provide a specified laminar air flow within the product zone17. Laminar air flow” refers to air (or fluid) flowing in parallel layers, without disruption between the layers. In some embodiments laminar flow refers to air flow without cross currents perpendicular to the direction of flow, nor eddies or swirls of fluids. In laminar flow the motion of the particles of fluid is very orderly with all particles moving in straight lines parallel to the air flow chamber walls. When a fluid (e.g., air) is flowing through a closed channel such as a pipe or between two flat plates, either of two types of flow may occur depending on the velocity of the fluid: laminar flow or turbulent flow. Laminar flow tends to occur at lower velocities, below the onset of turbulent flow. Turbulent flow is a less orderly flow regime that is characterized by eddies or small pockets of fluid particles which result in lateral mixing. In nonscientific terms laminar flow is “smooth”, while turbulent flow is “rough”. The dimensionless Reynolds number is an important parameter in the equations that describe whether flow conditions lead to laminar or turbulent flow. In the case of flow through a straight pipe with a circular cross-section, at a Reynolds number below the critical value of approximately 2300 fluid motion will ultimately be laminar, whereas at larger Reynolds number the flow can be turbulent. The Reynolds number delimiting laminar and turbulent flow depends on the particular flow geometry, and moreover, the transition from laminar flow to turbulence can be sensitive to disturbance levels and imperfections present in a given configuration. Whether flow within the air flow chamber duct will be laminar is dependent upon the Reynolds number associated with the system. The Reynolds number is derived from various parameters including the dimensions of the air flow chamber, the average velocity, and the viscosity and the density of the air in the air flow chamber. The conditions for laminar airflow are typically found with Reynolds numbers below 2300 or below 2000 or below 1000.

In many embodiments, the air flow chamber10includes a conveyor inlet opening22and a conveyor outlet opening24. The conveyor inlet opening22and the conveyor outlet opening24can form opposing open sides or open ends defining two sides of the air flow chamber10and particularly defining two sides of the product zone17. These openings22and24allow the food product conveyor20to move or convey food product25through the product zone17.

In preferred embodiments, the air pressure PCin the product zone is equal to or less than ambient pressure PAoutside the air flow chamber10. Thus, air does not flow from the air flow chamber10into the ambient environment surrounding the air flow chamber10. This pressure arrangement prevents oil laden air from being transmitted from the air flow chamber10into the ambient environment surrounding the air flow chamber10. The oil laden air is contained within the oil removal system and can be removed from the system as described below. Specifically air can flow from the ambient environment and into the air flow chamber10via the conveyor inlet opening22and the conveyor outlet opening24.

In many embodiments the air flow chamber10includes a vibrating element30that transmits vibration to the food product25to improve oil removal from the food product25. The vibrating element30can be any useful vibrating element vibrating at any useful oil removal frequency such as, at least 10 hertz or at least 20 hertz. The vibrating element30can transmit vibration through the conveyor20, or the vibrating element30can transmit vibration directly to the food product25, or a combination of these.

FIG. 3is a schematic block flow diagram of an illustrative food product oil removal and containment system. The air outlet14is fluidly connected to the air inlet12forming a closed loop air flow system.

An air flow generator50(such as a blower, for example) draws air flow from the air outlet14of the air flow chamber10and circulates this air flow to the air inlet12of the air flow chamber10. The air flow generator50provides air flow to the air flow chamber10at a rate of at least 10 meters/sec, or at least 15 meters/sec, or at least 20 meters/sec and the air flow chamber is configured to provide air flow in the product zone having a Reynolds number of 2000 or less, or 1000 or less. The air flow generator50can also provide the air pressure PCin the product zone17that is equal to or less than ambient pressure PAoutside the air flow chamber10, since the suction of the air flow generator50is in fluid connection with the product zone17of the air flow chamber10. In some embodiments this system approximates a wind tunnel system and can include elements useful in wind tunnels such as an air diffuser or louvers or vanes. An air diffuser can form a “honeycomb” grid section to assist in creating the laminar air flow.

A heating element60can be along this air flow path to increase the temperature of the air flow. In many embodiments the air flow temperature is increased to at least 100 degrees centigrade, or at least 120 degrees centigrade, or at least 150 degrees centigrade. The heating element60can be placed in any location along the air flow path.

An oil recovery unit40can be along this air flow path to remove and collect oil44entrained in the air flow. The oil recovery unit40can be placed in any location along the air flow path. Preferably the oil recovery unit40is located just downstream of the air outlet14of the air flow chamber10. In some embodiments, the oil recovery unit40can be an oil coalescing unit or include filter media to separate the oil particles from the air flow.

The system includes an air flow chamber10having a food product conveyor20for moving food product through the air flow chamber10in a direction70orthogonal to an air flow direction. Oil laden air exits the air flow chamber10at the air outlet14and can be processed by the oil recovery unit40. Oil cleaned air flow42enters the air flow generator50and is recirculated as blower outlet air52. The blower outlet air52can pass through the heating element60and exit as heated air62. The heated air62enters the air inlet12of the air flow chamber10.

FIG. 4is a schematic cross-sectional diagram of an illustrative air flow chamber having a food product25within the air flow.FIG. 5is a schematic cross-sectional diagram of an illustrative air flow chamber having a food product25and an air flow diverter element11within the air flow.FIG. 6is an illustrative taco shell food product25with residue oil dripping off the wing tips of the taco shell.

The air flow diverter element11diverts air flow from a portion of the food surface. The air flow diverter element11can preferentially divert air from a portion of the food surface. This can provide for more oil removal from chosen portions of the food surface. The illustrative air flow diverter element11is located upstream from the food product25.

The illustrative food product25inFIG. 4-6is a taco shell. The taco shell25includes a spline connecting two wing portions at corners. The conveyor20can hold the taco shell25along an inner portion of the spline of the taco shell25. Air flow travels from the air inlet12to the inlet air expansion zone16and onto the outer surface of the taco shell25in the product zone17. The illustrated taco shell configuration has a flat spline, it is understood that this is for illustrative purposes and the apparatus and method described herein can be utilized on any taco shell having any configuration such as a flat, rounded or V-shaped configuration.

While a taco shell is specifically illustrated, it is understood that the food product can be any food product where oil needs to be removed from a surface of the food product. Preferably the food product is a fried food product that was just fried or cooked in hot oil. These food products include snack products, or pizza or pizza roll products, or french fry products, or potato chip products.

FIG. 4illustrates air flow around the taco shell25without an air flow diverter element. In this arrangement, it is possible to remove more oil from the spline and corners of the taco shell25than is removed from the wing tips of the taco shell25. This can result in the spline and corners being more brittle than the wing tips of the taco shell25. This may not be desirable.

FIG. 5illustrates air flow around the taco shell25with an air flow diverter element11. The air flow diverter element11diverts air flow preferentially from the spline and corners of the from the taco shell25. In this arrangement, it is possible to remove more oil from the wings and wing tips of the taco shell25than is removed from the spline and corners of the taco shell25. This can result in the spline and corners being less brittle than the wing tips of the taco shell25. This may be desirable.

Thus, embodiments of OIL REMOVAL FROM FOOD SURFACE are disclosed. The implementations described above and other implementations are within the scope of the following claims. One skilled in the art will appreciate that the present disclosure can be practiced with embodiments other than those disclosed. The disclosed embodiments are presented for purposes of illustration and not limitation.