GB2582693A

GB2582693A - A continuous method of producing cooked pork rinds

Info

Publication number: GB2582693A
Application number: GB2000233.3A
Authority: GB
Inventors: William Openshaw David
Original assignee: FRESHERS FOODS Ltd
Current assignee: FRESHERS FOODS Ltd
Priority date: 2020-01-08
Filing date: 2020-01-08
Publication date: 2020-09-30
Anticipated expiration: 2040-01-08
Also published as: GB2582693B; GB202000233D0

Abstract

A continuous method of producing cooked pork rind comprising providing a cooking oil at a first temperature (140-155⁰C), introducing raw pork rind to the oil and allowing the temperature of the oil to decrease to a second temperature (90-100⁰C), before then increasing the temperature of the oil, to about 150⁰C and cooking the pork rind within the cooking oil. A continuous stream of pork rinds is maintained during the method. A cooked pork rind obtainable by the continuous method and a system for performing the continuous method are also described. Preferably, the oil temperature is maintained by circulating the oil between the frying vessel and a heating element and this circulation is prevented to decrease the temperature. Preferably the raw pork rind is frozen and fed into the vessel on a fryer conveyor belt and the cooked pork rind is fully immersed in the cooking oil, which may be a pork-based oil. On removal from the oil, preferably the cooked rind is cooled under a stream of air.

Description

A Continuous Method of Producing Cooked Pork Rinds

Field of the Invention

The present invention relates to a continuous method of producing cooked pork rinds and a system configured to perform the continuous method. The present invention also relates to a cooked pork rind obtainable by the continuous method of the present invention.

Background of the Invention

It is known that pork based snack foods (e.g. pork scratchings) can be prepared from raw pork rinds (or skin) using a range of cooking techniques. Frying techniques are typically used to cook pork rinds which involves, firstly, chopping the raw rinds into edible sized pieces before then frying the chopped rinds in a suitable cooking medium.

Traditionally pork fat or oil, often referred to as lard, is used as the cooking medium and the cooking process is carried out using a conventional frying tank or vessel. Once cooked, the pork rinds are removed from the cooking medium, cooled and packaged.

Well-established frying techniques generally involve a batch-type method whereby separate batches of raw pork rinds are manually chopped and fried in bulk. These methods are inefficient when producing cooked pork rinds on a large scale as they require the rinds to be processed by hand by multiple workers and require a number of frying vessels to increase throughput. The need for increased amounts of manual labour and machinery inflates the production costs, which ultimately reduces profitability.

Manually processed pork rind products may also vary in the quality depending on the person performing the cooking process. The step of chopping and cooking by hand also carries a greater safety risk to those manually cooking and operating frying vessels. In view of this, a number of continuous frying processes have been developed whereby chopped raw pork rinds are continuously carried on a conveyer belt into a cooking vessel containing cooking oil. The pork rinds then re-emerge from the vessel cooked and are then directed via the conveyer belt to a cooling and inspection table before being packaged. Whilst these continuous processes may overcome the efficiency and safety concerns associated with the batch-type methods, it has been found that the continuous cooking methods produce final cooked pork rinds which are less desirable as a snack food product due to a dry and hard texture being achieved in the final cooked pork rind product.

In view of the drawbacks associated with the known batch-type and continuous methods of producing cooked pork rinds, the present inventor has pioneered the development of a new continuous method which not only mitigates or overcomes one or more problems of the cooking techniques already available but also provides additional benefits as herein described.

Summary of the Invention

The present invention relates to a continuous method of producing a cooked pork rind which possesses efficiency and safety advantages over traditional batch-type cooking methods whilst at the same time achieving a superior cooked pork rind product as compared to products obtained using known continuous cooking methods.

In a first aspect of the present invention there is provided a continuous method of producing a cooked pork rind comprising: providing a raw pork rind; providing a cooking oil at a first cooking temperature; introducing the raw pork rind to the cooking oil at said first cooking temperature and allowing the temperature of the cooking oil to decrease to a second cooking temperature of from about 75°C to about 115°C; followed by increasing the temperature of the cooking oil above the second cooking temperature and cooking the pork rind within the cooking oil to provide the cooked pork rind; and maintaining a continuous stream of pork rinds within the cooking oil.

As mentioned above, the method of the present invention provides a more efficient and safe alternative to the well-established batch-type methods. Despite these batch-type methods suffering from efficiency and safety difficulties, the quality of the final product is generally considered to be favourable due to the final cooked pork rind products possessing a moist but crunchy texture which enhances its taste. Cooked pork rind products having these desirable characteristics have not yet been produced using the traditional continuous cooking methods. Without being bound by theory, it is thought that the superiority of the cooked pork rind products produced by traditional batch-type methods can be attributed to a wave-like (or sinusoidal) cooking temperature profile as the cooking method is performed. With these batch-type methods, raw pork rinds are initially placed into a frying vessel containing a cooking oil generally at an initial cooking temperature of 150°C. The pork raw pork rinds used in the batch-type methods are generally frozen (e.g. at a temperature of from about -25°C to about 0°C) at the point of entering the vessel and contacting the heated cooking oil. This has the effect of reducing the temperature of the cooking oil to around 75°C to 115°C but typically to about 95°C.

The frying vessel then slowly reheats the cooking oil until the initial cooking temperature of 150°C is reached again. This creates a wave-like temperature cooking profile as illustrated by the graph in Figure 2, described in more detail below, and ultimately results in the superior cooked pork rind product mentioned above. Currently used continuous cooking methods involve a flat line or constant temperature cooking profile whereby the entire cooking process is performed at a fixed high temperature which leads to a dry and hard textured final product. Not only has the present inventor managed to develop a method of continuously cooking pork rinds to attain the efficiency and safety benefits mentioned above but has also succeeded in establishing the wave-like cooking temperature profile required to produce favourable cooked pork rind products. The wave-like cooking temperature profile achieved by the method of the present invention is illustrated by the graph in Figure 3, described in more detail below.

Surprisingly and unexpectedly still, the continuous cooking method of the present invention also produces a cooked pork rind product which, importantly, has a lower fat content than that produced using traditional batch-type methods. This leads to significant downstream processing advantages. One such advantage relates to the improved tolerance of conventional packaging lines (i.e. systems configured to package or bag fried cooked pork rind products) to the final cooked pork product obtained from the continuous method of the present invention.

Packaging lines generally include a bulk bin in which cooked pork rinds are placed after they have cooled following cooking and quality inspection is performed. Cooked pork rinds are then fed from the bulk bin into a vibratory product feed which subsequently leads to a seasoning drum. Once the cooked pork rinds leave the seasoning drum they are transported using a bucket elevator to a multi-head weigher. The bucket elevator dispenses the cooked pork rinds onto the multi-head weigher which in turn feeds the pork rinds into a bagging machine via a hopper bucket.

It has been established that cooked pork rinds produced using traditional batch-type methods detrimentally cause excessive grease build up at multiple locations within downstream packaging lines. This causes clogging and damage to the packaging line leading to downtime of the packaging process and the need for repairs and maintenance work to be performed. It has been observed that the cooked pork rinds obtainable from the continuous method of the present invention circumvent such issues at the packaging stage. Without being bound by theory, it is considered that the unexpected lowering of the fat content of the cooked pork rinds produced by the method of the present invention mitigates the issues associated with grease build up within the packaging line.

It will be appreciated that the present invention is directed to a continuous method of producing a cooked pork rind. The continuous method of the present invention involves maintaining a continuous stream of pork rinds within the cooking oil during the cooking cycle. This may be achieved by simultaneously performing the step of introducing raw pork rind into the cooking oil whilst at the same time removing cooked pork rind from the cooking oil. It will be understood that this is possible only once the method of the present invention has run through its first cooking cycle when there is cooked pork rind within the cooking oil which can be removed. Maintaining a continuous stream of pork rinds within the cooking oil may be achieved using a conveyer belt system (e.g. twin fryer conveyer belt system). The conveyer belt may feed pork rinds into the cooking oil to create a continuous stream of pork rinds which flows into the cooking oil (i.e. introducing the raw pork rinds into the cooking oil) and flows out of the cooking oil as cooked pork rinds (e.g. removing the cooked pork rinds from the cooking oil). In some embodiments, the flow of pork rinds is automatically controlled and operated by a central processing unit (e.g. PLC controller). Optionally, the central processing unit may be in communication with a conveyer belt which is being used to create the continuous stream of pork rinds. In some embodiments, the continuous method of the present invention involves the uninterrupted flow of pork rind material through the method steps of the present invention.

The continuous method of the present invention has a number of advantages over known batch-type of discrete methods. These advantages include greater consistency in the final cooked pork rind product, reduced large scale manufacturing costs, as well as improved asset utilisation and safety. In embodiments of the present invention, the method may be performed repeatedly over any given period of time (e.g. repeatedly performing the cooking cycle of a given period of time). For example, the method may be performed repeatedly over a period of 6, 12, 24 or 48 hours.

In some embodiments of the first aspect of the present invention, the raw pork rind may include any portion of rind obtained from a suitable part of a pig's body. This includes the leg, loin, side, spare rib, hock, should and head. In particular, the raw pork rind may be obtained from the leg or shoulder of the pig. In other embodiments, the raw pork rinds may include partially cooked or cured pork rinds.

In further embodiments of the first aspect of the present invention, the raw pork rind may be diced or cut by machine or hand prior to being introduced to the cooking oil. The raw pork rinds may have a maximum dimension (e.g. side length, diameter or thickness) of cm. The raw pork rinds may typically have a maximum dimension of from about 2 cm to about 10 cm, from about 1 cm to about 10 cm, from about 2 cm to about 10 cm, from about 3 cm to about 10 cm, from about 4 cm to about 10 cm, from about 5 cm to about 10 cm, from about 1 cm to about 9 cm, from about 1 cm to about 8 cm, from about 1 cm to about 7 cm, from about 1 cm to about 6 cm or from about 1 cm to about 5 cm.

Preferably the raw pork rinds may have a maximum dimension of from about 2 cm to about 4 cm. In some embodiments, the raw pork rinds may have a width of from about 5 cm to about 10 cm, length of from about 20 cm to about 30 cm and/or depth/thickness of from about 1 cm to about 2 cm. Typically, the raw pork rinds may have a width of about 2.5 cm, length of about 2.5 cm and/or depth/thickness of from about 1 cm to about 2 cm.

In yet further embodiments, the raw pork rinds may have a width of about 2 cm, length of about 6 cm and/or depth/thickness of from about 1 cm to about 2 cm.

The raw pork rinds may be regular in shape, for example, triangular, square, rectangular, circular or any other desired configuration. The raw pork rinds may be irregular in shape.

In some embodiments of first aspect of the present invention, the cooking oil may be any suitable cooking oil capable of cooking raw pork rinds at cooking temperatures (e.g. the first cooking temperature and second cooking temperature) as described herein.

Suitable cooking oils include, but are not limited to, canola oil, coconut oil, vegetable oil, olive oil, peanut oil, sesame oil or any oil derived from animals (e.g. a tallow based oil or lard/pork based oil). Preferably, the cooking oil is a pork based oil.

In accordance with the method of the first aspect of the present invention, the cooking oil is provided at a first cooking temperature. In embodiments, the cooking oil is contained within a frying vessel and the first cooking temperature is achieved and/or maintained by heating the cooking oil. The heating may be achieved using any suitable heating element. Suitable examples of heating elements include gas burners, oil burners and electrical heating elements. Preferably, the heating element is an oil burner. It will be appreciated that, as described herein, the heating element may form part of a heat exchanger or any other component used in one or more steps of the method of the present invention.

In embodiments of the first aspect of the present invention, the cooking oil may be contained within a frying vessel and the first cooking temperature achieved and/or maintained by circulating the cooking oil between the frying vessel and a heating element. It will be appreciated that the frying vessel and heating element may be in fluid communication with one another to form a closed loop circuit. The closed loop circuit may include an outflow conduit through which cooking oil may flow within the closed loop circuit from the frying vessel to the heating element. The closed loop circuit may also include an inflow conduit through which cooking oil may flow within the closed loop circuit from the heating element back to the frying vessel. The closed loop circuit may allow the flow of cooking oil from the frying vessel through an outflow conduit to the heating element and then from the heating element through the inflow conduit and into the frying vessel.

For the avoidance of doubt, a conduit as described herein includes any suitable means of transporting cooking oil from one location to another. This includes, but is not limited to, tubing or open channels. Preferably, the conduit is tubing.

In further embodiments, the first cooking temperature may be any temperature suitable for cooking raw pork rinds and will depend on the type of cooking oil being used. Typically, the first cooking temperature is from about 100°C to about 200°C, from about 130°C to about 170°C or from about 140°C to about 155°C. In particular embodiments, the first cooking temperature is about 100°C, about 110°C, about 120°C, about 130°C, about 140°C, about 150°C, about 160°C, about 170°C, about 180°C, about 190°C or about 200°C. Preferably, the first cooking temperature is about 150°C or 135°C.

In accordance with the first aspect of the present invention, introducing the raw pork rind to the cooking oil at the first cooking temperature may include adding the raw pork rind to the preheated cooking oil or, alternatively, adding the preheated cooking oil to the raw pork rind. Typically, introducing the raw pork rind to the cooking oil may include feeding the raw pork rind into the frying vessel using a fryer conveyer belt. In such embodiments, the fryer conveyer belt may transport the raw pork rinds from an upstream position (e.g. from a dicer, hopper and/or screw conveyer arrangement) into the frying vessel. The transportation of the raw pork rinds may occur via a substantially horizontal movement of the fryer conveyer belt.

In some embodiments, the fryer conveyer belt may be a twin fryer conveyer belt which includes two separate belts for moving raw pork rinds from an upstream position into the frying vessel. Typically, the twin fryer conveyer belt includes a carrier belt which is operable to support the raw pork rinds within the cooking oil and prevents the raw pork rinds from dropping to the bottom of the frying vessel. The twin fryer conveyer belt may also include a second belt, which is positioned above the carrier belt but below the upper surface of the cooking oil within the frying vessel. This acts to ensure that the pork rinds are fully immersed within the cooking oil during the cooking phase of the method. In such embodiments, the raw pork rinds are prevented from reaching the surface of the cooking oil during the cooking process, keeping them fully immersed within the cooking oil, which helps achieve an even and uniform cook of the rinds. In some embodiments, the raw pork rinds are distributed evenly along the carrier belt, preferably in a single layer, so as to increase the surface area of the pork rinds exposed to the cooking oil. In further embodiments, the pork rinds may be distributed along the carrier belt in a uniform fashion (patterned fashion).

The method of the first aspect of the present invention involves introducing the raw pork rind to the cooking oil at said first cooking temperature and then allowing the temperature of the cooking oil to decrease to a second cooking temperature of from about 75°C to about 115°C. In embodiments, allowing the temperature of the cooking oil to decrease from the first cooking temperature to the second cooking temperature may be achieved by ensuring that the heating element responsible for heating the cooking oil is deactivated. In some embodiments of present invention, the temperature of the cooking oil is allowed to decrease by preventing the circulation of the cooking oil between the frying vessel and the heating element. In other embodiments, allowing the temperature of the cooking oil to decrease to the second cooking temperature is achieved by both deactivating the heating element and preventing the circulation of the cooking oil between the frying vessel and the heating element.

By deactivating the heat source responsible for heating the cooking oil or preventing the circulation of the cooking oil between the frying vessel and the heating element, the temperature of the cooking oil may be allowed to decrease to the second cooking temperature. In some embodiments, allowing the temperature of the cooking oil to decrease from the first cooking temperature to the second cooking temperature of from about 75°C to about 115°C occurs by virtue of the raw pork rinds having a cooling effect on the cooking oil temperature upon introducing the raw pork rinds to the cooking oil.

This is possible when the raw pork rinds are provided at a temperature which is lower than that of the first cooking temperature of the cooking oil and which is suitable for achieving a cooling effect upon the cooking oil. This cooling effect causes the temperature of the cooking oil to fall from the first cooking temperature to the second cooking temperature. In some embodiments of the present invention, the raw pork rinds are provided frozen or at an ambient temperature in order to achieve the cooling effect and cause the temperature of the cooking oil to decrease to the second cooking temperature. In conventional continuous methods, a heating cycle is designed to maintain a constant cooking temperature throughout the entire cooking cycle and therefore does not allow for the temperature of the cooking oil to drop when raw pork rinds (usually at a lower temperature) are introduced into the cooking oil. Instead, in these conventional continuous methods, the frying vessels often control the cooking temperature in reaction to the raw pork rinds being introduced, thus negating any cooling effect that might have occurred.

In embodiments of present invention, the raw pork rind is introduced to the cooking oil with the raw pork rind at a temperature of from about -25°C to about 25°C, from about 20°C to about 25°C, from about -15°C to about 25°C, from about -10°C to about 25°C, from about -5°C to about 25°C, from about 0°C to about 25°C, from about 5°C to about 25°C, from about 10°C to about 25°C, from about 15°C to about 25°C, from about 20°C to about 25°C, from about -25°C to about 20°C, from about -25°C to about 15°C, from about -25°C to about 10°C, from about -25°C to about 5°C, from about -25°C to about 0°C, from about -25°C to about -5°C, from about -25°C to about -10°C, from about -25°C to about -15°C or from about -25°C to about -20°C. Preferably, the raw pork rind is provided at a temperature of from about -25°C to about 25°C. Even more preferably, the raw pork rind is provided at a temperature of from about -20°C to about -15°C.

According to the first aspect of the present invention, the second cooking temperature is from about 75°C to about 115°C. Typically, the second cooking temperature may be from about 80°C to about 115°C, from about 85°C to about 115°C, from about 90°C to about 115°C, from about 95°C to about 115°C, from about 100°C to about 115°C, from about 105°C to about 115°C, from about 110°C to about 115°C, from about 75°C to about 110°C, from about 75°C to about 105°C, from about 75°C to about 100°C, from about 75°C to about 95°C, from about 75°C to about 90°C, from about 75°C to about 85°C or from about 75°C to about 80°C. Preferably, the second cooking temperature is from about 90°C to about 100°C. Even more preferably, the second cooking temperature is about 95°C.

In the first aspect of the present invention increasing the temperature of the cooking oil above the second cooking temperature and cooking the pork rind follows the step of allowing the temperature of the cooking oil to decrease to the second cooking temperature. Increasing the temperature of the cooking oil above the second cooking temperature may involve increasing the temperature of the cooking oil from the second cooking temperature to the first cooking temperature (i.e. until the first cooking temperature is reached). The increasing the temperature of the cooking oil may be achieved by circulating the cooking oil between a frying vessel and a heating element in an analogous manner to that described herein for achieving/maintaining the first cooking temperature of the cooking oil before introduction of the raw pork rinds to the cooking oil. It will be appreciated that the stage of "cooking the pork rind", which takes place after increasing the temperature of the cooking oil from the second cooking temperature, requires that the pork rinds are sufficiently cooked to provide edible cooked pork rinds as a final product. In other embodiments, the cooked pork rinds produced by the method of the present invention exclude partially cooked pork rinds.

Some embodiments of the first aspect of the present invention may involve circulating the cooking oil whilst the heating element is deactivated in order to prevent/minimise the formation of hot spots in the cooking oil within the frying vessel and/or to remove/reduce hot spots already formed in the cooking oil within the frying vessel. Typically, this is performed once the raw pork rind has been introduced to the cooking oil. This may be achieved by circulating the cooking oil between the frying vessel and the heating element whilst the heating element is deactivated. This allows the cooking oil to flow through the closed loop circuit formed between the frying vessel and heating element without increasing the temperature of the cooking oil within the frying vessel, whilst at the same time agitating the cooking oil so as to prevent/minimise the formation of hot spots or disperse any hot spots that might have formed. It will also be appreciated that the step of circulating the cooking oil aids in the removal of any water released from the raw pork rinds during the cooking process. In embodiments, there may be an external separator (e.g. a belt filter) positioned within the closed loop circuit and configured to remove water from the cooking oil during cooking oil circulation. The external separator may be positioned within the flow path of, or form part of, the outflow conduit as described above.

Alternatively, the external separator may be located within the flow path of, or form part of, the inflow conduit as described above.

In embodiments of the first aspect of the present invention, the circulation of cooking oil between the frying vessel and the heating element within the closed loop circuit described above is controlled by a pump. The pump may be located at any position within the closed loop circuit so as to effectively pump cooking oil around the circuit. Typically, the pump may be located within the closed loop circuit and positioned between the frying vessel and the heating element. Moreover, the pump may be located within the flow path of, or form part of, the outflow conduit as described above. Alternatively, the pump may be located within the flow path of, or form part of, the inflow conduit as described above.

As a further alternative, multiple pumps may be provided at different locations around the closed loop circuit.

It will be appreciated that when mentioned herein, circulation of cooking oil between the frying vessel and the heating element around the closed loop circuit may be performed at any suitable flow rate. In some embodiments, the circulation of cooking oil between the frying vessel and the heating element around the closed loop circuit may be performed at a flow rate of from about 50 litres per minute to about 500 litres per minute, from about 100 litres per minute to about 400 litres per minute, from about 100 litres per minute to about 300 litres per minute, from about 150 litres per minute to about 250 litres per minute or from about 180 litres per minute to about 220 litres per minute. Preferably, the circulation of cooking oil between the frying vessel and the heating element around the closed loop circuit may be performed at a flow rate of about 200 litres per minute. The cooking oil may be pumped around the closed loop circuit for example using the aforementioned pump(s). Careful control of the flow rate used during the circulation of cooking oil between the frying vessel and the heating element prevents the bunching up of pork rinds or waves of pork rinds being formed within the frying vessel (i.e. prevents pork rinds moving and gathering into the same area of the frying vessel).

The first aspect of the present invention, may involve cooling the cooked pork rind after cooking. This may be achieved by removing the cooked pork rinds from the cooking oil within the frying vessel before subjecting the cooked pork rinds to a cooling means. Typically, a stream of air created by cooling fans is used as the cooling means. The stream of air may have a flow rate of from about 1500 cubic metres per hour to about 4500 cubic metres per hour, from about 2000 cubic metres per hour to about 4000 cubic metres per hour, from about 2500 cubic metres per hour to about 3500 cubic metres per hour or from about 2800 cubic metres per hour to about 3200 cubic metres per hour. Typically, the stream of air may have a flow rate of about 3000 cubic metres per hour. In some embodiments, the step of cooling the cooked pork rind after cooking includes ensuring that the temperature of the cooked pork rinds is below a temperature of from about 25°C to about 35°C (preferably about 28°C or about 30°C) within from about 30 minutes to about 60 minutes (preferably about 45 minutes) of being removed from the cooking oil within the frying vessel. This type of rapid cooling advantageously prevent rancidity occurring within the cooked pork rind. This may be achieved by subjecting to the cooked pork rinds to a stream of air at a flow rate of about 3000 cubic metres per hour for about 45 minutes.

In a second aspect of the present invention there is provided a cooked pork rind obtainable by the continuous method according to the first aspect of the present invention or embodiments thereof as described herein.

In some embodiments of the first and second aspects of the present invention the cooked pork rind may have a fat content level of from about 45% to about 55%. It will be appreciated that the "%" denotes the percentage by mass of the overall mass of a given cooked pork rind. In other embodiments of the first and second aspects of the present invention the cooked pork rind may have a fat content level of from about 45% to about 50%, from about 45% to about 49%, from about 46% to about 49%, from about 47% to about 49% or from about 48% to about 49%. Preferably, the cooked pork rind may have a fat content level of from about 48.5% to about 49.5%, from about 48.6% to about 49.4%, from about 48.7% to about 49.3%, from about 48.8% to about 49.2%. Even more preferably, the cooked pork rind may have a fat content level of about 48.9%.

In a third aspect of the present invention, there is provided a continuous method of producing a cooked animal skin based edible product comprising the steps of: providing a morsel of animal skin; providing a cooking oil at a first cooking temperature; introducing the morsel of animal skin to the cooking oil and allowing the temperature of the cooking oil to decrease to a second cooking temperature of from about 75°C to about 115°C; and increasing the temperature of the cooking oil above the second cooking temperature and cooking the morsel of animal skin within the cooking oil to provide the cooked animal skin; and maintaining a continuous stream of animal skin within the cooking oil.

In embodiments or the present invention, the term "animal skin" may include the skin of any suitable animal. For example, this may include the skin of a chicken, cow or pig. Moreover, any portion of the skin of the respective animal may be used or the skin in its entirety. Any one or more of the embodiments described in connection with the first and second aspects described herein could be combined with one or more features of the third aspect relating to the continuous method of producing a cooked animal skin based edible product as appropriate.

In a fourth aspect of the present invention there is provided a system configured to perform the continuous method according to any one of the first or third aspects of the present invention or any embodiment thereof.

Description of Figures

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying Figures in which: Figure 1 is an illustration of a cooking system configured to carry out the method of the present invention.

Figure 2 is a plot illustrating the temperature profile of the cooking oil during a conventional batch-type cooking method.

Figure 3 is a plot illustrating the temperature profile of the cooking oil during a continuous cooking method of the present invention.

Detailed description of the Invention

The invention will be further described, by way of example only, with reference to the accompanying Figures.

Cooking system Referring to Figure 1, there is schematically illustrated a system 1 configured for performing the continuous method according to the present invention.

The system 1 incorporates a hopper 2 labelled 'Dicer' or Fig 1 having an input end and an output end connected via a chute, which is typically conical. Diced frozen raw pork rinds are loaded into the hopper 2 through the input end and focussed by the chute portion of the hopper towards an infeed screw conveyer 3. Once the frozen raw pork rinds pass through the chute section of the hopper 2 they are fed onto the infeed screw conveyer 3 via the output end of the hopper has an outlet end not the chute.

The infeed screw conveyer 3 transports the frozen raw pork rinds onto a twin fryer belt system 4. The twin fryer belt system 4 includes two separate belts for moving the frozen raw pork rinds into a frying vessel 5. The frozen raw pork rinds are supported on a carrier belt (not shown) which carries the pork rinds through cooking oil within the frying vessel 5. The carrier belt is fully immersed within the cooking oil within the frying vessel. A second belt, positioned above the carrier belt but also fully immersed within the cooking oil, ensures that the pork rinds are fully immersed within the cooking oil located within the frying vessel during the cooking phase of the process. The pork rinds are prevented from reaching the surface of the cooking oil during the cooking process which helps achieve an even cook.

As previously mentioned, the frying vessel 5 is filled with a cooking oil, typically, a pork based oil. The cooking oil is first brought to a cooking temperature of approximately 150°C. The frozen raw pork rinds are then immersed in the cooking oil by the twin fryer belt system 4 feeding the pork rinds into and through the frying vessel 5.

The system 1 is configured to circulate the cooking oil between the frying vessel 5 and a heat exchanger 6 (as illustrated by the black arrows in Figure 1). During circulation, the cooking oil flows out of the frying vessel 5 through an outflow conduit 9 which is in fluid communication with the heat exchanger 6. The cooking oil flows into the frying vessel 5 from the heat exchanger 6 through an inflow conduit 10. The circulation of the cooking oil is achieved using pump 7 which is located along the outflow conduit 9 between the frying vessel 5 and heat exchanger 6. The heat exchanger 6 includes a heating element 8 (e.g. an oil burner) that produces heat which is then used to heat the circulating cooking oil. The cooking temperature of the cooking oil in the frying vessel 5 is maintained or increased by running pump 7, whilst the heating element 8 is also activated (i.e. turned on). Running of the pump drives the circulation of the cooking oil between the frying vessel 5 and the heat exchanger 6, as well as the movement of heated oil into the frying vessels. Circulation occurs between the frying vessel 5 and the heat exchanger 6 via a closed loop cooking oil circuit formed by the outflow and inflow conduits 9 and 10 respectively. The temperature of the cooking oil in the frying vessel 5 can also be decreased or allowed to reduce by preventing circulation of the cooking oil around the closed loop cooking oil circuit. This is achieved by stopping pump 7 and/or deactivated heating element 8. Stopping the pump 7 prevents the cooking oil from circulating, which in turn prevents the movement of heated cooking oil into the frying vessel 5. This allows the stationary (non-circulating) cooking oil within the frying vessel 5 to cool by virtue of heat loss to the surrounding environment. When the heating element 8 is deactivated, the circulating cooking oil is no longer heated, which also allows the cooking oil in the frying vessel 5 to cool.

Cooking method First cooking and cooling phase In this specific example of a method according to the present invention there is a first cooking phase in which the pump 7 is started and the heating element 8 activated. This causes the cooking oil to circulate between the frying vessel 5 (which forms part of the overall twin fryer belt system 4) and the heat exchanger 6 via outflow and inflow conduits 9 and 10 respectively. As the cooking oil circulates, the temperature of the circulating cooking oil increase as it passes the heat exchanger 6. The cooking temperature of the cooking oil in the frying vessel 5 is increased until an initial cooking temperature of approximately 150°C is reached. The carrier belt, filled end-to-end with frozen raw pork rinds, is then fed into the frying vessel 5 containing the cooking oil at the initial cooking temperature (as illustrated by the white arrows in Figure 1). The feeding motion of the carrier belt is then stopped together with deactivation of pump 7 and heating element 8.

This prevents the circulation of the cooking oil between the frying vessel 5 and the heat exchanger 6 and also causes the temperature of the cooking oil in the frying vessel 5 to gradually decrease in response to the freshly introduced frozen pork rinds. The cooking temperature then slowly drops to a temperature of approximately 95°C.

Circulation phase After approximately 5 minutes, a circulation phase is initiated by starting pump 7 again for a period of approximately 15 seconds. This circulates the cooking oil within frying vessel 5 to help equalise the cooking temperature across the frying vessel 5 and prevents the formation of hot spots within the cooking oil. Since the heating element 8 is deactivated at this stage the cooking temperature of the cooking oil within the frying vessel continues to drop. The activation of pump 7 is repeated three times over a 15 minute period in order to perform three separate circulation phases. In addition to the temperature equalising effect, the circulation of the cooking oil also aids in the removal of any water released from the pork rinds during the cooking process. This is achieved via an external separator 11 (e.g. belt filter) which is positioned along the path of the outflow conduit 9, between the frying vessel 5 and the heat exchanger 6.

Second cooking phase Once the temperature of the cooking oil has dropped to approximately 95°C and the circulation phase completed, the heating element 8 is activated. Circulation, using pump 7, and heating of the cooking oil starts again and causes the temperature of the cooking oil in the frying vessel 5 to gradually increase. Once the cooking oil reaches a temperature of approximately 150°C again, the heating element 8 is deactivated whilst the pump 7 remains active to continue during the circulation of the cooking oil. At this point the temperature of the cooking oil falls slightly, by approximately 5°C, during which time the pork rinds continue to cook for another 10 minutes to provide the cooked pork rinds. The twin fryer belt system 4 is then started again and the cooked pork rinds discharged from the frying vessel 5 before being fed into a cooling and inspection station 12. The discharged cooked pork rinds are then spaced apart before being subjected to a stream of cooling air created by cooling fans. The stream of air has a flow rate of 3000 cubic metres per hour and reduces the temperature of the cooked pork rinds to less than around 28°C within approximately 45 minutes. The cooled pork rinds are then left at room temperature for at least one hour before downstream storage and packaging steps are performed.

While the cooked pork rinds are being removed, the temperature of the cooking oil is increased again to an initial cooking temperature of approximately 150°C and the next batch of frozen raw pork rinds then automatically fed into the frying vessel 5.

The entire cooking process is performed continuously and is controlled automatically using a central processing unit (e.g. PLC controller). The central processing unit communicates with the hopper 2, infeed screw conveyer 3, twin fryer belt system 4, heating element 8 of heat exchanger 6 and pump 7 to command the various cooking, cooling and circulation phases over a defined cycle time. It will be appreciated that various temperature sensors are integrated into system 1 and communicate with the central processing unit in order to control the temperature profile of the cooking oil within the frying vessel 5 throughout the cooking cycle.

Cooking temperature profile As discussed earlier, the continuous cooking method of the present invention successfully creates a wave-like cooking temperature profile by including the first cooking phase, cooling phase, circulation phase and the second cooking phase as described above. The graph in Figure 3 illustrates the wave-like cooking temperature profile achieved by the method of the present invention. This wave-like cooking temperature profile of the present invention can be seen to be similar to that achieved by a conventional batch-type process as illustrated in the graph of Figure 2. It will be appreciated that a typical cooking temperature profile of a known continuous cooking method would be represented by a flat-line on a similar type of graph illustrating a constant temperature profile during the cooking cycle.

Fat content measurements It will be appreciated that fat content levels of cooked pork rind products may be determined by various techniques known to the person skilled in the art. Fat content levels for cooked pork rinds produced by a batch-type method and the continuous method of the present invention are described herein and were measured by an independent laboratory (Microsearch Laboratories Ltd). The exemplary analysis technique performed by the independent laboratory involves the determination of fat content levels by acid hydrolysis (Procedure No: CH4031; Issue Date: February 2018).

A detailed exemplary procedure for determining the fat content of cooked pork rind products by acid hydrolysis is provided below: 1. Obtain a representative sample of the food material (e.g. cooked pork rinds) to be analysed (e.g. approx. 200g).

2. Render the sample uniform using an appropriate knife mill (e.g. a Retch Grindmax GM200).

3. Weigh 1-2g of the minced sample into a 250m1 conical flask, recording the exact mass (ma).

4. Add both anti-bumping granules and 50m1 of 4M hydrochloric acid to the conical flask.

5. Swirl the flask to ensure no sample is stuck to the bottom.

6. Connect the conical flask to a condenser and turn on the condenser water supply.

7. Heat the conical flask using a hotplate until the contents begin to boil. Continue to boil for 40 minutes.

8. Turn off the hotplate and allow the flask to cool slightly. Add 40m1-50m1 of warm water through the condenser to ensure any material is washed into the flask. Remove the flask while still warm.

9. Place a fluted filter paper into a funnel, moisten the filter paper with hot tap water and slowly pour the contents of the conical flask into the filter paper.

10. Wash the filter paper and its contents with hot tap water until the washings no longer turn blue litmus paper to red.

11. Place the drained filter paper into an aluminium foil tray. Allow to air dry overnight.

12. Place the aluminium foil tray (with the filter paper), a clean extraction thimble and a cotton wool insert into a drying oven at 103°C +1-2°C for at least one hour.

13. After removing the items from the oven, roll up or fold the filter paper and insert it into the extraction thimble.

14. Wipe both the operators gloves and the foil tray with the cotton wool insert in order adsorb any residual oil that had been transferred from the filter paper. Place the cotton wool insert into the top of the thimble.

15. Place extraction thimble into the desiccator and allow to cool for a period between 15-45 minutes.

16. Weigh the extraction thimble (m1).

17. Place the thimble into a Soxhlet extraction apparatus.

18. Extract with light petroleum sprit for at least 2 hours. The quantity of solvent should be one and a half to two times the capacity of the body of the extractor.

The light petroleum spirit should distil between 40°C and 60°C, have a bromine index less than 1§ and its residue on complete evaporation should not exceed 0.002g/100m1.

19. After extraction, remove the thimble from the extraction chamber and allow any residual petroleum spirit to evaporate.

20. Dry the thimble for at least 1 hour in the drying oven at 103°C +/-2°C. Allow to cool for a period between 15 and 45 minutes in the desiccator 21. Reweigh the extraction thimble (m2).

22. Calculate the fat content using the formula given below.

Fat content = -m2) x 100) / mu Where: mo = mass (g) of the sample portion m1 = mass (g) of the dried thimble before extraction m2 = mass (g) of the dried thimble after extraction The fat content for cooked pork rinds produced by a batch-type method as compared to the continuous method of the present invention is presented in Table 1 below.

Cooking Method Percentage by mass Batch-type method 51.5% Continuous method according to 48.9% Invention

Table 1

The data presented in Table 1 illustrates a reduction in the fat content when moving from a conventional batch-type process to the continuous method of the present invention. Whilst the difference in fat content between the cooked pork rind products is less than 5% this translates to significant differences in the grease build-up observed in the downstream packaging lines.

It will be appreciated that numerous modifications to the above described cooking methods, system and cooked pork rind may be made without departing from the spirit and scope of the invention, for instance, the scope of the invention as defined in the appended claims. Moreover, any one or more of the above aspects/embodiments could be combined with one or more feature of the other aspects/embodiments and all such combinations are intended with the present disclosure.

Optional and/or preferred features may be used in other combinations beyond those explicitly described herein and optional and/or preferred features described in relation to one aspect of the invention may also be present in another aspect of the invention, where appropriate.

The described and illustrated embodiments are to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all change and modifications that come within the scope of the invention as defined in the claims are desired to be protected. It should be understood that while the use of words such as "preferable", "preferably", "preferred", or "more preferred" in the description suggest that a feature so described may be desirable, it may nevertheless not be necessary and embodiments lacking such a feature may be contemplated as within the scope of the invention as defined in the appended claims. In relation to the claims, it is intended that when words such as "a". "an" or "at least one" are used to preface a feature there is no intention to limit the claim to only one such feature unless specifically stated to the contrary in the claims.

Claims

CLAIMS: 1. 2. 3. 4. 5. 6.A continuous method of producing a cooked pork rind comprising: providing a raw pork rind; providing a cooking oil at a first cooking temperature; introducing the raw pork rind to the cooking oil and allowing the temperature of the cooking oil to decrease to a second cooking temperature of from about 75°C to about 115°C; followed by increasing the temperature of the cooking oil above the second cooking temperature and cooking the pork rind within the cooking oil to provide the cooked pork rind; and maintaining a continuous stream of pork rinds within the cooking oil.
The continuous method according to claim 1 wherein the cooking oil is contained within a frying vessel and the first cooking temperature is maintained by circulating the cooking oil between the frying vessel and a heating element.
The continuous method according to claim 2 wherein the temperature of the cooking oil is allowed to decrease by preventing the circulation of the cooking oil between the frying vessel and the heating element.
The continuous method according to any one of the preceding claims wherein the step of increasing the temperature of the cooking oil comprises increasing the temperature of the cooking oil to the first cooking temperature.
The continuous method according to any one of the preceding claims wherein the first cooking temperature is from about 130°C to about 170C or from about 140°C to about 155°C, preferably, about 150°C.
The continuous method according to any one of the preceding claims wherein the second cooking temperature is from about 90°C to about 100°C, preferably, about 95°C.
7. The continuous method according to any one of the preceding claims wherein the at least raw pork rind is provided at a temperature of from about -25°C to about 25°C, preferably, from about -20°C to about -15°C.
8. The continuous method according to any one of the preceding claims wherein introducing the raw pork rind to the cooking oil comprises feeding the raw pork into the frying vessel using a fryer conveyer belt.
9. The continuous method according to any one of the preceding claims further comprising circulating the cooking oil whilst the heating element is deactivated for a sufficient period of time in order to minimise the formation hot spots in the cooking oil within the frying vessel and/or to reduce hot spots already formed in the cooking oil within the frying vessel.
10. The continuous method according to any one of the preceding claims further comprises cooling the cooked pork rind under a stream of air after removing the cooked porked rinds from the cooking oil.
11. The continuous method according to any one of the preceding claims wherein the raw pork rind is fully immersed within the cooking oil.
12. The continuous method according to any one of the preceding claims wherein the cooking oil is a pork based oil.
13. A cooked pork rind obtainable by the continuous method according to any one of the preceding claims.
14. A system configured to perform the continuous method according to any one of claims 1 to 13.