WO2025133404A1

WO2025133404A1 - Fryer and frying process

Info

Publication number: WO2025133404A1
Application number: PCT/EP2024/088414
Authority: WO
Inventors: Anthony Fletcher; Jean HENTZEN
Original assignee: Believe In Science Ltd
Current assignee: Believe In Science Ltd
Priority date: 2023-12-22
Filing date: 2024-12-23
Publication date: 2025-06-26
Anticipated expiration: 2026-06-22
Also published as: GB202319963D0; GB2636843A

Abstract

There is provided a system for cooking dough products, the system comprising: a conveyor for transporting a dough product, a plurality of oil dispensers configured to dispense a flow of cooking oil to the dough product on the conveyor to enrobe the dough product in cooking oil and thereby cook the dough product. Also provided is a method for cooking confectionery products, the method comprising: providing such a cooking system, transporting an uncooked dough product on the conveyor through the flows of cooking oil dispensed from the plurality of oil dispensers to produce a cooked dough product.

Description

Fryer and Frying Process

Technical Field

The present invention relates to the field of food fryers and cooking processes therefor. More specifically, the invention relates to fryers and processes for cooking confectionery products.

Backo round

Fried confectionery products are a popular indulgence in many countries and include products such as donuts, beignets, churros etc. Broadly speaking, doughnuts fall into one of two categories: cake doughnuts and yeast doughnuts. Cake and yeast doughnuts share many ingredients, and are mostly distinguished by the leavening agent used within the recipe. Yeast doughnuts use yeast within the dough, which is proofed in order to produce a light and fluffy texture in the final product. In contrast, cake doughnuts are batter based rather than dough based, and use a chemical leavener such as baking powder. Cake donuts are less reliant on gluten development within the product in order to provide the desired structure and texture, compared to yeast donuts.

Both cake and yeast doughnuts are deep fried, resulting in a high fat content in the final product. There have been multiple attempts to make healthier doughnuts, for example by reducing the sugar, fat and/or calorie content. However, all existing attempts have produced a significantly inferior texture and taste of the final product. One method to reduce the calorie content of confectionery products is to increase the water content. Within baking however, this is known to have a negative impact on the product’s ability to rise and increases the stickiness of the dough, making it very difficult to handle efficiently.

An alternative approach to improving the healthiness of a donut was developed by the present applicant and is described in patent application EP22178229.5. This involves adjusting the donut recipe to improve the structure such that the dough can be precooked e.g. via baking or steaming. Such processes are effective but increase the processing cost and requires careful balancing of the ingredients and additives to provide the necessary dough structure. The calorie content of a doughnut may also be lessened by reducing the oil content of the dough product. JPH03127941 A describes reducing the overall oil content of dough products by avoiding deep-frying the dough product in oil, but rather by spraying oil onto the uncooked (or partially cooked) dough, followed by a cooking step using hot air. As such, the oil spray is insufficient to cook the dough product and a final cooking step using hot air is required. However, it is known within baking that cooking the product to completion using hot air after oil treatment can overly dehydrate the dough, resulting in a dry doughnut.

The present invention attempts to provide a healthier confectionery product which does not suffer from the problems of the prior art. of invention

According to a first aspect of the invention, there is provided a system for cooking dough products. The system may comprise a conveyor for transporting a dough product. The system may comprise a plurality of oil dispensers. The oil dispensers may be configured to dispense a flow of cooking oil to the dough products on the conveyor e.g. to enrobe the dough product in cooking oil and thereby cook the dough product. As such, the system is configured to provide a flow of cooking oil to the dough product on the conveyor to provide a film of cooking oil across the entire surface of the dough product and thereby cook the dough product. The film of cooking oil may be continuous. Furthermore, a constant flow of hot cooking oil provides a constant delivery of heat towards the dough product. In contrast to a spray of oil, which is unable to provide sufficient thermal energy to rapidly cook the dough product, necessitating a longer cooking process or a subsequent cooking process which cause the dough product to dry out and be less palatable to consumers, and which also results in more rapid oxidation and therefore degradation of the cooking oil, the present invention allows for a dough product to be cooked rapidly by covering the entire surface of the dough product with a flow of cooking oil, which evenly cooks the product from all sides, allowing a more even and more rapid cooking without the dough product sitting in a pool of oil. The present invention is able to provide sufficient heat energy to cook the dough product by way of the flow of cooking oil without the need for a separate downstream cooking step. The inventors have found that by enrobing the dough product in cooking oil, the entire surface of the dough product can be cooked effectively and evenly. Furthermore, this can be achieved with greater control and with a reduced cooking time (e.g. reduced frying time). In this way, the hot cooking oil consistently covers and heats the dough product simultaneously, which rapidly heats the dough product so that the cooking oil can deliver all the heat necessary to complete the cooking of the dough product. Therefore, it is not necessary to implement a subsequent cooking step, such as an oven bake which typically takes longer to cook the product compared to hot oil, thereby removing moisture from the dough product, resulting in a dried-out cooked dough product. The components of the system may be of the like provided by Lynnmoore Engineering Co Ltd of King’s Lynn, United Kingdom.

The oil flows may enrobe the dough products as they pass through the flow of cooking oil. For example, the oil dispensers may be analogous to a chocolate or icing enrober used for decorating confectionery. The dispensers may be configured to supply a laminar flow of cooking oil. The inventors are currently of the opinion that a laminar flow of cooking oil is preferable, since it minimises splashing of the hot oil which increases the oxidation thereof. Further advantageously, a smooth flow of oil also helps the oil cling or adhere to the surface of the dough products, e.g. as a film of oil, and to flow around the surface of the product being cooked. This enrobing action ensures that the cooking oil flows over the full surface of the dough product, including the surface opposite to the oil dispenser e.g. in comparison to a conventional float fryer which cooks only one side of the products at a time. The invention thus provides an improved and uniform heat transfer from the oil to the whole surface of the dough product, improving the final product and reducing cooking time.

The oil dispensers may be configured to dispense a curtain of cooking oil. The curtain, as opposed to a spray or shower, of the cooking oil is preferable due to a reduced exposure of the oil to air, thereby reducing oxidation. The oil dispensers may comprise an elongate outlet which thus produces said curtain of cooking oil along its length. The oil dispensers may comprise a weir. The weir may comprise an oil inlet, a well and a lip, over which the cooking oil flows. The oil dispensers may be identical. The oil dispensers may extend the full width of the conveyor i.e. in a direction perpendicular to the direction of travel of the conveyor. In alternative embodiments, the oil dispensers may supply a spray or shower of cooking oil, or one or more linear streams which are configured to enrobe the dough product in cooking oil.

The conveyor may be configured to allow cooking oil to pass therethrough. The conveyor may be configured to direct cooking oil away from the dough product positioned thereon. The conveyor may be configured such that cooking oil cannot pool on the conveyor e.g. in contact with the dough product. Such embodiments reduce the ingress of cooking oil into the dough product, thereby providing a healthier product. As such, by avoiding pooling of oil, the dough product does not sit in a pool of oil, which can be absorbed into the product, resulting in a higher-calorie product.

The system may further comprise one or more air blowers. The air blowers may be configured to supply a flow of air to the cooked dough products e.g. to remove residual oil. The air blowers may be unheated. The air blowers may be heated. The one or more air blowers may be an air knife. The air knife(s) may be configured to supply a curtain of air to the cooked dough product. As used herein, the term ‘air knife’ refers to a blower having a linear nozzle e.g. to provide a thin curtain of air. Preferably the blowers are sufficiently powerful to supply a high speed jet or curtain of air. The inventors have found that oil is typically absorbed into the donut through capillary action, and thus the air blowers minimise the contact time of the oil on the surface after cooking is complete. The one or more air blowers is configured to blow oil off the dough product rather than as a further cooking step. Preferably the blowers are positioned less than 40s, 35s, 30s, 25s, 20s, 15s, or 10s after the final oil dispenser. It will be understood that a position defined by a time will reflect a variable physical position depending on the conveyor speed. E.g. the blowers are positioned such that the dough products pass beneath within the time limit noted above. Shorter times between the final oil dispenser and the blowers is also desirable since the oil will be hotter and less viscous and thus easier to remove from the surface.

The system may further comprise a chamber. The chamber may house at least the plurality of oil dispensers. The chamber may house the air blowers. The chamber may comprise an input opening. The chamber may comprise an output opening. The conveyor may be configured to transport the dough product from the input opening to the output opening. The conveyor may extend through the input and/or output openings e.g. for cooperation with a further conveyor or product handling apparatus. The chamber may comprise a roof and/or faces which extend around a base. The chamber may retain within the heat from the heated oil e.g. the internal temperature of the chamber may be greater than ambient. The internal air temperature within the chamber may be 20-200°C, 30-190°C, 40-180°C, 50-170°C, 60-160°C. 70-150°C, 80- 140°C, 90-130°C, 100-120°C, or 110°C. It will be understood that end points of ranges can be combined in any manner herein. It will be understood that the temperature within the chamber will be a gradient, with the temperature at the input opening lower than immediately adjacent to the first oil dispenser. The chamber may comprise a heater for increasing the temperature within the chamber. The heater may comprise one or more heating elements, gas burners, infrared heaters, or other suitable heating device. The chamber may thus serve to act as an oven to bake the dough products as they pass therethrough on the conveyor. The chamber may comprise one or more fans or air circulation devices in order to better distribute the heat within the chamber.

In some embodiments, the system may further comprise an oven configured to pre-bake the dough products. E.g. the oven may be positioned prior to the oil dispensers. The oven may have a temperature of 100-180°C, 110-170°C, 120-160°C, 130-150°C, or 140°C. The system may be configured to provide a residence time of the dough product in the oven of 30s-120s, 40-1 10s, 50-100s, 60-90s, or 70-80s. Additionally or alternatively, the system may further comprise a steamer configured to pre-cook the dough products. E.g. the steamer may be positioned prior to the oil dispensers. The steamer may have a temperature of 100-180°C, 110-170°C, 120-160°C, 130-150°C, or 140°C. In some embodiments, the oven and/or steamer are integrated with the chamber. The conveyor may pass through an oven and/or steamer section, prior to passing a further section comprising the oil dispensers. It will be understood that end points of ranges can be combined in any manner herein.

The system may have a distance of at least 20 cm between the input opening and the first of the plurality of oil dispensers. The distance may be at least 30cm, 40cm, 50cm, 60cm, 70cm, 80cm, 90cm, 100cm, 1 10cm, 1200cm or 130cm. In some embodiments, the distance may be less than 200cm, 180cm, 160cm, 150cm, 140cm, 130cm, 120cm, 1 10cm, 100cm, 90cm, 80cm, 70cm, 60cm, or 50cm. The distance above may comprise the distance between the input opening and the flow of oil from the first of the oil dispensers. The system may be configured to provide a residence time of the dough product in the chamber prior to the first oil dispenser of 30s-120s, 40-110s, 50-100s, 60- 90s, or 70-80s. It will be understood that end points of ranges can be combined in any manner herein.

The system may further comprise a proofer. The proofer may be configured to hold the uncooked dough products in conditions to promote proving of the dough. The proofer may have an internal temperature of 25-40°C, 27-38°C, 28-37°C, 30-35°C, 31 -34°C, or 32-34°C. The proofer may have an internal relative humidity of 50-80%, 55-75%, or 60- 70%. The prover may have more than one zone whereby the zones have different temperatures and/or humidity. The uncooked dough products may be held within the proofer for 30-55 minutes, 35-50 minutes, 40-45 minutes, 41 -44 minutes 42-43 minutes. It will be understood that end points of ranges can be combined in any manner herein. The inventors have found that the more proofed the dough, the greater the formation of bubbles and blisters on the upper surface of the product i.e. where the cooking oil contacts first. By proofing the dough for a shorter amount of time, the products are less susceptible to bubbles and blisters. Shorter proofing times lead to less expansion of the dough and also a ‘weaker’ dough i.e. with a less developed gluten structure. The inventors have also found that the reduced proofing can be mitigated through pre-baking of the dough within the chamber, and also through selection of oil temperatures and flow rates.

The system may comprise a further conveyor for transporting the proofed dough products from the proofer e.g. to the conveyor and oil dispensers and/or oven and/or steamer. The further conveyor may comprise one or more conveyor belts formed from a resilient and/or flexible material. Preferably the belt material is highly elastic. The resilient conveyor belts may be configured to cushion the proofed dough products when they contact the further conveyor e.g. when deposited from the prover swing. Careful handling is desirable so as to not deform or knock the gas from the proofed products, which are typically delicate and would conventionally have been deposited directly into a fryer, thus minimising impact. The conveyor may be of the kind supplied by Lynnmoore Engineering Co Ltd of King’s Lynn, United Kingdom.

The system may further comprise one or more rails. The plurality of oil dispensers may be connectable to the one or more rails e.g. such that the positions of the plurality of oil dispensers are adjustable. The rails may comprise a series of mounting points to which the oil dispensers may be connectable e.g. by a mechanical fastener. The positions of the dispensers may be adjustable in one direction, or in two directions. One direction may be parallel to the length of the conveyor e.g. the dispensers may be movable longitudinally of the conveyor and/or system. For example, the dispensers may be movable toward and away from an end of the chamber and/or the blowers. One direction may be perpendicular to the length of the conveyor e.g. the direction may be (approximately) vertical and the dispenser may be configured to be raised and lowered. In some embodiments, the dispensers can be raised and lowered relative to the rails. In further embodiments, the rails may be raised and lowered e.g. relative to the conveyor. The system may be configured such that the oil dispensers are set as far away from the input opening as possible, such that the dough products undergo a pre-baking step.

The conveyor may be an endless conveyor. The conveyor may comprise a belt through which oil can flow. The belt may comprise a chain link, mesh, or similar construction. The belt may be porous. The belt may comprise a series of apertures through which oil can flow. The aperture size may be between 1 -15mm, 2-14mm, 3-13mm, 4-12mm, 5-1 1 mm, 6-10mm, 7-9mm or 8mm. It will be understood that end points of ranges can be combined in any manner herein. The aperture may be round, square, or any other shape. The aperture size of the belt is a balance between the need to support the delicate uncooked dough products and the desire to allow oil to flow away from the products quickly.

The conveyor may comprise a belt located above an oil tray. The oil tray may be configured to catch the oil from the oil dispensers. The system may further comprise a recirculating pump configured to supply oil from the oil tray to the oil dispensers.

The system may further comprise a heater for heating the oil. The heater may comprise one or more heating elements. The heating elements may be located within the oil tray to heat the oil therein. The heating element(s) may be located approximately beneath the dispensers. Such an arrangement avoids the oil cooling throughout the system e.g. in collection areas. Additionally or alternatively, the system may comprise one or more in-line heaters configured to heat the oil within pipes connecting the oil tray and the oil pump and/or between the oil pump and the plurality of oil dispensers. Additionally or alternatively, the heater may comprise one or more electric heating elements, gas powered heaters, heat exchangers, or induction heaters. The system may further comprise a filter for filtering the oil. The filter may be located within the oil tray, within a filtering unit, and/or within pipes connecting the oil tray and the oil pump. Preferably the filter is located prior to the oil pump.

The system may be configured to supply oil from the oil dispensers at a temperature of 150-200°C. Optionally, the system may be configured to supply oil from the oil dispensers at a temperature of 160-190°C, 165-185°C, 170-180°C, or 175°C. It will be understood that end points of ranges can be combined in any manner herein.

The system may be configured to supply oil from the oil dispensers at a flow rate from each dispenser of 10 to 80 litres per minute (L/min). The system may be configured to supply oil from the oil dispensers at 15-75 L/min, 20-70 L/min, 25-65 L/min, 30-60 L/min, 35-55 L/min, 40-50 L/min, or 45 L/min. The oil dispensers may have an outlet with a width of 50-150cm, 60-140cm, 70-130cm, 75-125cm, 80-120cm, 90-1 10cm or 100cm. The outlet may have a height (i.e. a length measured perpendicular to the width) of 1 - 10mm, 2-9mm, 3-8mm, 4-7mm, or 5-6mm. The outlet may have a cross-sectional area of 5-150cm², 10-140 cm², 20-130 cm², 30-120 cm², 40-1 10 cm², 50-100 cm², 60-90 cm², or 70-80 cm². The system may be configured to provide a flow rate through the oil dispenser outlets of 0.1 to 15, 0.5-14, 1 -13, 2-12, 3-1 1 , 4-10, 5-9, 6-8, or 7 litres per cm². The system may comprise an oil pump having an output of up to 200 to 300 L/min. The oil pump may have an output of 50-350 L/min, 75-325 L/min, 100-300 L/min, 125-275 L/min, 150-250 L/min, 175-225 L/min, or 200 L/min. It will be understood that end points of ranges can be combined in any manner herein. The output of the oil pump is divided by the number of oil dispensers being used, and thus the flow rate from the dispensers can be decreased by using a greater number of oil dispensers, or increased by closing down oil dispensers. Similarly, the flow rate at a single point on the conveyor will vary with the outlet size of the oil dispensers, since the flow would be spread across the outlet. In one series of embodiments, the system comprises an oil pump with a maximum output of 200-300 L/min and comprises 3 to 6 oil dispensers.

The system may be configured to supply air from the air blowers at an ambient temperature. For example, ambient temperatures may comprise between 10 and 25°C. Alternatively, the air blowers may comprise a heater and be configured to supply air at above ambient temperatures e.g. 25-150°C, 50-125°C, or 75-100°C. Alternatively, the blowers may comprise an air intake from within the chamber in order to provide air at above ambient temperatures. The system may be configured to supply air from the air blowers at a flow rate of 50-250 m³/hour, 75-225 m³/hour, 100-200 m³/hour, 125-175 m³/hour, or 150 m³/hour. The system may comprise an air pump or fan configured to supply air to the one or more blowers at 100-500 m³/hour, 150-450 m³/hour, 200-400 m³/hour, 250-350 m³/hour, or 300 m³/hour. It will be understood that the speed of the air exiting the blowers is variable upon the size and number of the blower outlets. The blower may comprise an air knife between 50-150cm, 75-125cm, 80-120cm, 90-110cm or 100cm. It will be understood that the greater the distance between the blower outlet and the conveyor, the greater the air entrainment and the air output will become more turbulent. The blower outlet may be 5-15cm above the surface of the conveyor, or 5- 14cm, 7-13cm, 8-12cm, 9-11 , or 10 cm above the surface of the conveyor. It will be understood that end points of ranges can be combined in any manner herein.

The conveyor may have a speed of 0.5-2 cm/s, 0.75-1.75 cm/s, 0.8-1.7 cm/s, 0.9-1.6 cm/s, 1 -1 .5 cm/s, 1 .1 -1 .4 cm/s, or 1 .25 cm/s. In some embodiments, the conveyor speed is 0.9-1 .0 cm/s. The system may be configured such that the residence time of the dough product under oil is 10-80s, 15-70s, 20-60s, 25-55s, 25-50s, 30-45s, or 35-40s. It will be understood that end points of ranges can be combined in any manner herein.

According to a second aspect of the invention, there is provided a method for cooking confectionery products. The method may comprise providing a cooking system as described above. The method may comprise transporting an uncooked dough on the conveyor through the flows of cooking oil dispensed from the plurality of oil dispensers to produce a cooked dough. Preferably, no subsequent cooking steps are required as the flow of cooking oil from the plurality of oil dispensers provides enough thermal energy to cook the dough product without further cooking steps. As the system is configured to provide cooking oil in a flow to the entire surface of the dough product, the dough product can be rapidly and evenly cooked. In addition, by providing a flow of oil rather than simply submerging the dough product partially or fully in cooking oil, there can be greater rate of heat transfer and therefore cooking, resulting in a more pleasingly moist product. Although deep frying brings the dough product into direct contact with the oil, moisture released from the dough product as well as heat absorption by the dough product reduces the local temperature of the cooking oil. In contrast, a flow of cooking oil maintains a more even temperature of the cooking oil as it is only in contact with the dough product for a short time before being replaced by new cooking oil. The cooking system may comprise one or more air blowers configured to supply a flow of air to the cooked dough product, and the method may comprise transporting the cooked dough through the flow of air from the one or more air blowers to remove residual cooking oil.

The method may comprise operating the system under the conditions described above, and statements of the first aspect are combinable with the second and vice versa.

The method may comprise wherein the uncooked or partially cooked dough is conveyed through cooking oil at a temperature of 160-190°C and/or having a flow rate of 10-80 L/minute per oil dispenser. The method may comprise conveying the dough through flows of oil from 3 to 6 (i.e. 3, 4, 5 or 6) oil dispensers.

The dough product may comprise a dough-based confectionery product. The dough product may comprise a sweet or savoury doughnut. The dough may comprise any conventional dough composition. The dough product may be non-planar. The dough product may be shaped as a sphere, an oblate spheroid, an ellipsoid, a ball, a solid torus, or any shape with a smooth, curved, three-dimensional surface of any aspect ratio. The inventors have found that a dough product of a smooth, curved, three-dimensional shape assists with complete enrobement of the cooking oil across the entire surface of the dough product, including the surface opposite to the oil dispensers. A dough product of a smooth, curved, three-dimensional shape is preferable, since it prevents excessive splashing when coating the dough product with the cooking oil, which increases the oxidation thereof. The dough product may have the shape of traditional doughnuts, such as ring doughnuts (substantially circular with a central hole) or filled doughnuts (a flattened sphere). The dough product may have a thickness of 10 mm or more. The dough product may have a thickness of 10% or greater, 20% or greater, 30% or greater, 40% or greater, or 50% or greater than its diameter. Very thin dough products, such as tortillas, do not require complete enrobement during cooking as it is possible for heat to transfer through them readily.

In one series of embodiments, the dough comprises 40-60wt% wheat flour, 0.5-3wt% yeast, 0-5wt% oil and/or fat, and 20-40wt% water. The dough may comprise 42-58 wt%, 44-56 wt%, 45-55 wt%, 46-54 wt%, 48-52 wt%, or 50 wt% of wheat flour. The dough may comprise 0.75-2.75 wt%, 1 -2.5 wt%, 1 .25-2.25 wt%, 1.5 - 2 wt% of yeast. The yeast may be fresh or dried yeast. The dough may comprise 0.1 -4.5 wt%, 0.5-4 wt%, 1 -3.5 wt%, 1 .5-3 wt%, 2-2.5 wt% of oil. The oil may be any edible liquid or solid oil, such as rapeseed, sunflower, vegetable, coconut, palm oils, shortening or similar. The dough may comprise 22-38 wt%, 24-36 wt%, 25-35 wt%, 26- 34 wt%, 28-32 wt%, or 30 wt% of water. It will be understood that end points of ranges can be combined in any manner herein.

The dough may comprise 0-20wt% of a donut concentrate or additives. A donut concentrate may comprise a blend of one or more of flour, sugar(s), emulsifiers, leavening agents, whey powder, stabilisers, and/or flour treatment agents. The additives may comprise the same blend but omitting flour and/or sugar. The dough may comprise at least 0.1 wt%, 0.25 wt%, 0.5 wt% or 0.75 wt% of donut concentrate or additives. In some embodiments, the dough may comprise 1 -19 wt%, 3-17 wt%, 5-15 wt%, 7-13wt%, 9-1 1 wt%, or 10 wt% of donut concentrate or additives. In many commercial donut concentrates, the largest proportion is wheat flour, in which case the wt% of the additives within the dough will be significantly lower than of the concentrate overall within the dough. It will be understood that end points of ranges can be combined in any manner herein.

The dough may comprise 0-2 wt% salt. The dough may comprise 0.1 -1.9 wt%, 0.2-1.7 wt%, 0.3-1 .5 wt%, 0.4-1 .3 wt%, 0.5-1 .1 wt%, 0.6-1 .0 wt%, or 0.7-0.9 wt% salt. It will be understood that end points of ranges can be combined in any manner herein.

According to a third aspect of the invention, there is provided a dough-based confectionery product produced according to the method described herein. The confectionery product may be a doughnut e.g. a ring or ball doughnut.

Brief Description

The invention will now be described with reference to the following Figures, wherein: Figure 1 is a perspective view of a system for cooking confectionery products; Figure 2 is a perspective view of the system wherein the roof is removed; Figure 3 is a lengthwise cross-section through the system viewed from the side; and

Figure 4 is a cross section showing part of the system in close up.

Specific Description

Turning now to Figures 1 and 2, there is shown a system 1 for cooking dough products. The system comprises a chamber 2 mounted on a support frame 21 to raise the chamber 2 to a conventional working height. The chamber 2 is formed by a roof 22 and a base 23. The roof 22 has an upper face 25, a pair of side faces 27 on opposing sides of the upper face 25, end faces 29 and a series of angled panels 26 which extend between the upper face 25 and the side faces 27. Each end face 29 has an aperture 31 which serve as the infeed and outfeed for the system.

In Figure 2 the roof 22 has been removed to show the internal components of the system 1 . The system has a conveyor 32 having a pair of rollers 33 and a continuous belt (not shown) extending therebetween. A series of belt supports 35 extend along the length of the system to support the upper surface of the belt, and a series of cross members 36 are positioned along the length of the conveyor 32 to provide further support and assist in oil runoff. The rollers 33 are positioned outside of the chamber 2 in order to transport products into and out of the chamber 2. The belt (not shown) is configured to allow cooking oil to pass freely through, and is preferably a chain link, mesh or similar construction. The belt may comprise apertures of any suitable size in order to permit the oil to flow through - for example, the mesh may be a 4mm square mesh (a 4x4mm mesh), or it may have a greater aperture size, such as up to a 15x15mm square mesh.

With additional reference to Figures 3 and 4, the base 23 is positioned underneath the roof 22 and beyond each of the end faces 29. The base 23 has an oil tray 37 extending underneath the conveyor 32 and is configured to receive the oil falling through the conveyor. The oil tray 37 is provided with heaters therein, such as heating elements 45 which, in use, are immersed in the oil within the oil tray 37. The oil tray 37 has a reservoir 39 at an end thereof which is connected via oil conduits 40 to an oil pump 41 and subsequently to an oil manifold 43, whereby it is distributed to a series of six weirs 47. The weirs 47 are mounted on a pair of rails 49 connected to the side faces 27 of the roof 22. The rails 49 have a pair of slots 491 (see Figures 4) through which fasteners 493 extend in order to fix the position of the rails 49. The slots 491 thus allow the simple height adjustment of the rails 49, and thus all of the weirs 47, above the conveyor 32. Each weir 47 is connected to the oil manifold 43 via and a flexible hose 46 such that the weirs 47 can be easily movable along the rails and mounted in position (e.g. with mechanical fasteners). A valve 48 is provided between the oil manifold 43 and flexible hose 46 such that each weir 47 in the system can be activated/deactivated as per the user’s requirements and according to the cooking process being operated. The system is also provided with an air pump 51 which is connected to a pair of blower outlets in the form of air knives 53.

T urning now to Figure 4, there is shown a close up of a cross-section through the system 1 . The weirs 47 each comprise a pair of mounting plates 471 which are connectable to the rails via mechanical fasteners. The weir 47 is formed from a metal plate, such as stainless steel, and has a rear wall 473, lower surface 475 and a mouth 477. The rear wall 473, lower surface 475 and mouth 477 thus define a well 470 therein. The mouth 477 in turn has a barrier 479 and a lip 481 which are provided with a thin slot therebetween to act as the oil dispenser outlet such that oil can flow between the barrier 479 and the lip 481. In the embodiment shown, the mouth 477 has a width of approximately 95cm and the distance between the barrier 479 and lip 481 is approximately 5mm. The rear wall 473 is provided with a mesh filter 483 which defines an inlet 482 into which the end of the flexible hose 46 supplies oil. The mesh filter 483 serves as a simple filter to prevent any remaining solids from flowing through into the well and to disrupt the oil flow such that oil entering the weir 47 fills the well 470. As the oil level within the well 470 rises, it eventually reaches the mouth 477 and flows over the lip 481 onto the conveyor 32 below. The weir 47, and in particular the mouth 477 (e.g. the lip 481 and barrier 479), are configured to induce laminar flow of the oil over the lip 481 onto the conveyor 32 below, such that the conveyor passes through a curtain of oil. Furthermore, the oil flow rate into the weir 47, the oil selection (and thus characteristics such as viscosity), and oil temperature all affect the ability of the weir 47 to form a laminar flow of oil over the lip, and thus can be adjusted as necessary depending on the cooking programme being operated.

The air knives 53 extend perpendicularly across the conveyor 32 and are connected to the air pump 51 via pipes 53. The air knives have an outlet slot 533 therein which faces the conveyor 32 to provide a curtain of air through which the conveyor 32 passes. During a cooking operation, the system is heated by the heating elements 45 located within the oil tray 37 of the base 23. The roof 22 extends over the base 23 to form the chamber 2 i.e. a largely enclosed cavity in which the cooking process is carried out. The conveyor 32 extends from both ends of the chamber 2 to transport raw products into the chamber and cooked products from the chamber 2, and can integrate with any conventional food handling and transport systems such as further conveyors etc. By providing the chamber 2 rather than using an open fryer, more of the heat is retained within the system, thus simultaneously reducing energy losses to convection and more quickly cooking the products. The hot oil is pumped from the well 39 by the oil pump 41 and to the weirs 47, which are each independently positionable and controllable to provide a highly adaptable system. The valves 48 can be opened or closed depending on which weirs the user wishes to operate, and to control the flow of oil from each weir. The oil flow rate can thus be adjusted across all of the weirs by adjusting the pump rate, but equally, individual weirs can be balanced or reduced through control of the valves 48.

The uncooked products are picked up by the conveyor 32 (e.g. on the left hand side in Figures 2 and 3) and enter into the chamber 2. The heat within the chamber 2 can act as a partial baking step to continue cooking the products therein even when not under oil. The products then pass under a series of weirs 47 and through a curtain of hot oil falling from the weirs 47. The laminar flow of the oil from the weir encourages the oil to adhere to the surface of the products and thus ensures a consistent coverage over the surface of the products being cooked. A laminar flow of oil reduces splashing when contacting the products - splashing oil reduces the energy transfer to the products which increases the cost of the process through increased heating requirement, in addition to potentially uneven cooking and surface coloration. The oil then drains off the surface of the products, through the conveyor belt and into the oil tray for recirculation and/or filtration. The products then continue onwards to pass underneath the air blowers (e.g. the air knives 53) to remove residual oil from the surface of the products. The cooked products then exit the far end of the chamber 2 where they can be transported for further processing such as cooling, decoration, and packaging.

In some embodiments (not shown) the system can be provided with further cooking apparatus prior to the chamber. E.g. the system may further comprise an oven or steam oven prior to the chamber for pre-baking or pre-steaming the confectionery products. Such ovens may be conveyor-based ovens and thus feed directly into the conveyor 32 of the system 1 , or may require transport from a conventional oven. The system may integrate with subsequent downstream apparatus, such as coolers or drying apparatus, or decoration and/or filling systems.

The system 1 thus provides the operator with many points of adjustability in order to achieve the desired cooking process. For example, the total frying time is a function of the conveyor belt speed and number of oil dispensers which supply oil to the dough products. It has been found that the surface temperature of the dough products drops rapidly when no longer under cooking oil e.g. after passing an oil dispenser. Since the oil flows rapidly off the products, they are not fried when not being supplied with oil from an oil dispenser. Thus to increase the frying time, a slower conveyor and/or a greater number of oil dispensers is necessary.

The total cooking time is a function of the conveyor belt speed and length of the conveyor, since this includes any baking time prior, between, or after the frying steps e.g. due to the increased temperature within the chamber.

The position of the weirs relative to the conveyor provides further a mechanism for adjusting the cooking profile a product will undergo. As noted above, the surface temperature of the dough drops rapidly when not under oil. Thus, a short, constant frying process can be achieved by grouping the oil dispensers together. Similarly, a long, variable cooking profile can be achieved by spacing the oil dispensers apart. Such a profile may represent alternating periods of baking and frying e.g. low energy transfer and high energy transfer. The oil dispensers may be grouped together in varying configurations to provide different frying steps. For example, they may be grouped closely together and moved away from the inlet side end wall such that the products undergo a pre-baking step, due to the internal temperature of the chamber, prior to a single uniform frying step. Such a pre-baking step could be in addition to or instead of a pre-baking step using an oven or steamer. In some examples, the weirs may be configured in two or more groups with different flow rates or even oil temperatures such that the products pass through two or more distinct frying zones e.g. a high flow, high energy zone; a lower flow, lower energy zone; or variations thereof. The system of the present invention thus has a greater number of variable which can be adjusted to achieve the desired final product e.g. the final colouration and centre temperature. As noted above, the embodiment of the Figures has six weirs, but the system may have any suitable number, and the weirs can be individually controlled (e.g. they may not all be needed in some cooking processes). The position of the weirs relative to the air blowers also defines the contact time of the oil on the surface of the products being cooked, and thus a longer distance between weirs and blowers would be expected to lead to greater oil absorption into the products. Additionally, due to the internal temperature of the chamber, a longer distance between weirs and blowers can act as a baking step post-frying.

The operating parameters of the weirs themselves can be controlled to give a desired cooking process. Although the temperature of the oil within the embodiment shown will be uniform across the system, the flow rate of the oil from the weirs can be individually set e.g. by adjusting the valves between the manifold and each weir. In a conventional deep fryer, the cooking speed is dependent upon the oil temperature. However, in the present system, the cooking speed is also dependent upon the oil flow rate, wherein high oil flow speeds from the weirs leads to much more rapid transfer of heat energy to a product, and thus quicker cooking speeds. The frying rate needs to be configured so that the centre of the products is completely cooked without overcooking or burning the outer surface. This can be advantageous since it provides a desirable browning of the surface of the product while reducing the contact time and thereby minimising oil absorption into the products. A further advantage is in the precise control of the product expansion during cooking. As dough products are heated, they expand (conventionally known as ‘oven spring’) due to the heating and expansion of gases such as CO2 trapped within the gluten matrix in the dough. The present invention thus gives very precise control of how much and when heat energy is supplied to the product in a way which is not achievable in a conventional float fryer. As discussed above, the doughs are preferably underproofed in order to achieve a weaker dough and avoid blistering of the product surface. This increased control of the heat energy supplied to the product during the frying gives greater control for the expansion and can thus compensate for the reduced expansion during proofing.

A further advantage is that the height of the weirs can be adjusted as described above depending on the desired cooking process. A lower weir means that the air exposure of the oil is reduced, which thus reduces the oxidation of the oil and lengthens usable lifetime of the cooking oil. At the same time, the weir height can be set to ensure that smooth flow of oil is achieved over the surface of the product. The viscosity of the oil means that the oil can wrap around the product to fry all of the surfaces.

Examples

Example A - fat content

A conventional yeast donut dough was prepared consisting of: wheat flour 51 wt%, donut concentrate 10.5wt%, fresh yeast 1.7wt%, rapeseed oil 1.6wt%, reduced sodium salt 0.7wt%, and water 34.5wt%. The donut concentrate was Easy Donut™ supplied by Puratos® and comprises wheat flour, dextrose, emulsifiers (E471 , E481 ), raising agents (E450, E500, E501 ), whey powder, rapeseed oil, salt, stabilisers (E412, E466) and a flour treatment agent (E300). The dough was formed into small balls and proofed. They were then fried using three different techniques to assess the impact on the fat content of the products. The three cooked samples were then cooled and analysed, and the results shown in Table 1 below.

Comparison 1 - The proofed donuts were fried in a conventional float fryer for 90 second on each side at an oil temperature of 180°C. The donuts had a pleasing golden brown colour.

Sample 2 - The donuts were fried using the system 1 shown in Figures 1 to 4. The proofed donuts were transferred to the conveyor and passed through the system. The system was operated with 4.5 oil dispensers (i.e. with four weirs fully open and one further weir on half flow); the conveyor speed was set at 1 .1 cm.s^-1 ; the oil pump was set at 50% of the maximum frequency thus supplying oil to the four weirs at approximately 125L/min, and the oil temperature between 170-180°C. The air pump was operating at maximum output of 400 m³/hour split between two air knives.

Sample 3 - The donuts were pre-baked prior to frying using the system 1 . The proofed donuts were baked in a fan oven for 75 seconds at a temperature of 140°C with a fan speed setting of 1 . The pre-baked donuts were then transferred to the system 1 and the cooking process of Example 2 was repeated.

Table 1

The mass gain was calculated by weighing the donuts when removed from the prover and then subtracting this from the mass measured after frying was complete. The values were normalised to a 40g donut in order to allow direct comparison. The samples were then sent for external analysis to determine the fat, saturated fat, and moisture content. The fat content was measured using an Oracle™ Rapid NMR fat analyser from CEM corporation. The saturated fat content was determined by gas chromatography, and the moisture content determined by oven drying of the sample at 103°C and weighing the remainder.

The inventors have found that frying the donuts using the system 1 (i.e. Samples A2 and A3) provided an equally enjoyable donut with similar colouration to the comparison 1. However, the system produces donuts which have a significantly reduced fat content compared to conventional frying. The moisture content of A3 was found to be higher than comparison A1 which was reflected in a softer texture achieved in the final product. A value for the moisture content of Sample A2 was not obtained, but the texture was equally soft and pleasurable as A3, and thus the moisture content was concluded to be equivalent or higher than comparison A1. Without wishing to be bound by theory, it is believed that the shorter frying times and more rapid cooking lead to the greater retention of moisture in the final product.

Example B - system configuration

In a second series of experiments, a second, batch of dough for making confectionery products was prepared as described in Example A and cooked using the system 1 described herein. Various settings of the system 1 were adjusted to provide nine cooking profiles - the system settings are shown in Table 2 below. The effects on the colour of the cooked products were investigated using a Colormeter software app (ColorMeter RGB Colorimeter developed by White Marten GmbH) installed on an iPhone®, and the results recorded in Table 3. The Colormeter results define three properties of the surface colour of the cooked confectionery product as defined by the Commission Internationale de I’Eclairage (CIE). ‘L’ indicates lightness, wherein a lower number indicates a darker coloured surface, and ‘a’ and b’ are the red/green coordinate and yellow/blue coordinate respectively. The oil temperature was maintained between 170°C and 180°C so that the effect of the other system settings could be compared directly.

Table 2

In the data in Table 3 below, the value of L indicates the darkness/lightness of the surface of the fried donuts, and thus is used as a proxy for determining the level of cooking which has been performed. As shown by Examples B1 to B3, increasing the speed of the conveyor lead to a lighter surface colouration on the products due to a reduced time for the product to be under hot oil. This test was then repeated with the oil pump speed set to 50% (down from 75%). Examples B4 to B6 were all lighter than the equivalent Examples B1 to B3, demonstrating that oil pump speed can be selected in order to increase or decrease the amount of energy transferred to the surface of the donut without changing oil temperatures. Examples B7 to B9 were then operated under maximum cooking conditions, by opening all of the oil weirs within a six weir system and operating

colouration than the comparative examples operated with fewer weirs and at lower oil flow rates. Lastly, example B10 is a repeat of example B4 and was carried out to demonstrate the consistency of the cooking process and the system, providing very a nearly identical darkness and colour profile.

Table 3

The inventors have found that ColorMeter L values of 35 to 45 represents a pleasingly cooked product. Below L= 35, the products tend to be too dark and are overcooked. Above L=45 the products tend towards too light and are undercooked.

Claims

CLAIMS:

1 . A system for cooking dough products, the system comprising: a conveyor for transporting a dough product, a plurality of oil dispensers configured to dispense a flow of cooking oil to the dough product on the conveyor to provide a film of the cooking oil across the entire surface of the dough product and thereby cook the dough product.

2. The system of claim 1 , wherein the conveyor is configured to allow cooking oil to pass therethrough and/or to direct cooking oil away from the dough product positioned thereon.

3. The system of any one of the preceding claims, further comprising one or more air blowers configured to supply a flow of air to the cooked dough product to remove residual oil, and optionally, wherein the one or more air blowers is an air knife configured to supply a curtain of air to the cooked dough product.

4. The system of any one of the preceding claim, further comprising a chamber which houses at least the plurality of oil dispensers, and optionally the air blowers.

5. The system of any one of the preceding claims, wherein the chamber comprises an input opening and an output opening, and wherein the conveyor is configured to transport the dough product from the input opening to the output opening.

6. The system of any one of the preceding claims, wherein the system has a distance of at least 200mm between the input opening and the first of the plurality of oil dispensers.

7. The system of any one of the preceding claims, further comprising one or more rails and wherein one or more of the plurality of oil dispensers is connectable to the one or more rails such that the positions of the plurality of oil dispensers are adjustable.

8. The system of any one of the preceding claims, wherein the conveyor comprises a belt located above an oil tray configured to catch the oil from the oil dispensers, and wherein the system further comprises a recirculating pump configured to supply oil from the oil tray to the oil dispensers.

9. The system of any one of the preceding claims, wherein the system is configured to supply oil from the oil dispensers at a temperature of 160-190°C and/or at a flow rate from each dispenser of 10 to 50L/min.

10. The system of any one of the preceding claims, wherein the system is configured to supply air from the air blowers at an ambient temperature and/or at a flow rate of 50- 250 m³/hour .

11 . The system of any one of the preceding claims, wherein the conveyor has a speed of 0.5 to 2 cm/s, and optionally, wherein the system is configured such that the residence time of the dough product under oil is 10-80s.

12. The system of any one of the preceding claims, further comprising an oven configured to pre-bake the dough products at a temperature of 100-180°C prior to the plurality of oil dispensers, and optionally, wherein the system is configured to provide a residence time of the dough product in the oven of 30-120s.

13. A method for cooking confectionery products, the method comprising: providing a cooking system according to claim 1 , transporting an uncooked dough product on the conveyor through the flows of cooking oil dispensed from the plurality of oil dispensers to produce a cooked dough product.

14. The method according to claim 13, wherein the uncooked dough product is conveyed through cooking oil having a temperature of 160-190°C and/or having a flow rate of 10-50 L/minute per oil dispenser.

15. A dough-based confectionery product produced according to the method of either claim 13 or 14.