Process for upcycling waste food material

Abstract

A process for manufacturing a snack food product comprises (a) obtaining a starting material comprising carbohydrate and which has undergone a heating or drying process and comprises 30 wt.% or less o

Description

The present invention relates to a process for upcycling waste food and food byproducts to form snack food products, and to snack food products produced by such processes. BACKGROUND OF INVENTION Food waste is a major global problem, both in monetary terms and environmentally. The processes involved in producing and transporting food consume significant resources such as energy and water, and the breakdown of waste food can produce damaging greenhouse gases. Bread is a particularly problematic example of food which is wasted, being a staple food in many parts of the world and having a relatively short shelf-life. As such, the reduction of bread waste during both the manufacturing process and once in the hands of the consumer has huge economic and environmental potential. It is therefore an object of the present invention to provide a process for preparing a food product, in particular a snack food product, prepared from unwanted food products, food byproducts, and from food manufacturing waste. SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided a process for manufacturing a snack food product, comprising the steps of: a) obtaining a starting food material comprising carbohydrate, wherein the starting food material comprises 30 wt.% or less of water; and wherein the starting food material has been subjected to a pre-processing step involving heating and / or drying; b) passing the starting food material through a screw press (3) comprising a screw barrel (5), wherein the screw barrel (5) comprises a rotatable screw (7) within a barrel (9), the screw barrel (5) having a first end (11) and a second end (13); wherein the starting food material enters the first end of the screw barrel (11) via an inlet (15) in the screw press, and the snack food product exits an outlet (19) in the screw press via the second end of the screw barrel; and the channel depth (31) of the screw decreases between the first end and the second end of the screw barrel; and the channel depth of the screw at the second end of the screw barrel where the snack food product exits the screw barrel is approximately zero. According to a second aspect of the invention, there is provided a snack food product, preferably obtained using a process as described herein. BRIEF DESCRIPTION OF FIGURES The above and other aspects of the invention will now be described, by way of example only, with reference to the following figures, of which: Figures 1 is a side view of a screw press of use in one embodiment of the process of the invention. Figure 2 is a side view of an alternative screw press of use in an embodiment of the process of the invention. Figure 3 is a side view of a section of a screw barrel located within a screw press. Figure 4a is a perspective view of a screw which is suitable for use in the process of the invention. Figure 4b is a perspective view of a screw barrel which is suitable for use in the process of the invention. Figure 5a shows a snack food product being formed as it exits the screw barrel (Example 5 -using potato chips). Figure 5b shows a snack food product produced using Doritos™ (Example 5). Figure 5c shows a snack food product produced using brioche bread (Example 3). Figure 5d shows a snack food product produced using white bread (Example 1). Figure 5e shows a snack food product produced using chocolate croissant (Example 4). In the Figures, it should be noted that the screw press components are not drawn to scale, and the Figures are merely intended to illustrate the relative positions of the components within the screw press, and should not be construed as being limiting. DETAILED DESCRIPTION The process according to the present invention converts waste food material into a snackfood product, using a screw press which is configured to convert the starting waste food material into a cohesive and durable snack food product. As illustrated in Figures 1-3, the screw press (3) comprises a screw barrel (5). The screw barrel (5) comprises a rotatable screw (7) within a barrel (9), and the screw barrel has a first end (11) and a second end (13). The screw press (3) is a compression-type screw press, typically used for oil (e.g. seed and nut) pressing. The starting food material enters the first end of the screw barrel (11) via an inlet (15) in the screw press, and the snack food product exits an outlet (19) in the screw press, via the second end of the screw barrel. The screw barrel (5) is shown in greater detail in Figure 3. Screw (7) resides within barrel (9). The screw is formed from a central screw root (7a) which may also be described as a screw shaft, and a screw flight (7b). The screw is axially rotatable, and as it rotates within the barrel, starting food material (and intermediate food material that is being converted to a snack food product) is advanced along the length of the barrel, and is ultimately ejected through the outlet. In one embodiment, the screw rotates at a speed of between about 30 RPM and about 250 RPM, such as between about 30 RPM and about 180 RPM, between about 40 RPM and about 100 RPM, between about 40 RPM and about 80 RPM, e.g. around 60 RPM. Prior art processes involving food extrusion cooking (with an extrusion die) tend to use much a much higher rotation speed. The distance between the screw root (7a) and outer edge of the screw flight (7b) is defined as the screw channel depth (31). Put another way, the screw channel depth can be defined as the difference between the major and the minor dimension of the screw. For the avoidance of doubt, the major and minor dimensions of the screw in this context are across the diameter of the screw (major dimension (41) and minor dimension (43) as shown in Figure 3). The channel depth (31) of the screw decreases between the first end and the second end of the screw barrel; and the channel depth of the screw at the second end of the screw barrel where the snack food product exits the screw barrel is approximately zero, or zero i.e. the screw is no longer flighted at the second end of the screw barrel. Put another way, the difference between the major and minor dimension of the rotatable screw decreases between the first and second ends of the screw barrel, wherein the difference is approximately zero, or zero, at the second end of the screw barrel. Thus, the process of the invention can also be described as a process for manufacturing a snack food product, comprising the steps of: a) obtaining a starting food material comprising carbohydrate, wherein the starting food material comprises 30 wt.% or less of water; and wherein the starting food material has been subjected to a pre-processing step involving heating and / or drying; b) passing the starting food material through a screw press (3) comprising a screw barrel (5), wherein the screw barrel (5) comprises a rotatable screw (7) within a barrel (9), the screw barrel (5) having a first end (11) and a second end (13); wherein the starting food material (1) enters the first end of the screw barrel (11) via an inlet (15) in the screw press, and the snack food product exits an outlet (19) in the screw press via the second end of the screw barrel; and the difference between the major and minor dimension of the rotatable screw decreases between the first and second ends of the screw barrel, wherein the difference is approximately zero at the second end of the screw barrel. As shown in Figure 3, the screw root clearance (35) is the distance between the screw root (7a) and the inner surface of barrel (9). The screw clearance (33) is the distance between the outer edge of the screw flight (7b) and the inner surface of barrel (9). If the flight has tapered to approximately zero or zero, the screw clearance is effectively the same as the screw root clearance. The screw clearance (33) (or screw root clearance (35) if the flight has tapered to approximately zero or zero) is typically between about 0.2 mm and 0.8 mm, such as between about 0.2 mm and about 0.7 mm, between about 0.2 mm and about 0.5 mm, or between about 0.3 mm and about 0.5 mm e.g. about 0.4 mm. In one embodiment, the screw clearance is constant along the length of the screw barrel, or varies by less than 0.5 mm, e.g. less than 0.4 mm, less than 0.3 mm, less than 0.2 mm or less than 0.1 mm. If the screw clearance varies, it is typically greater at the first end compared to the second end of the screw barrel. In one embodiment, the difference between the diameter of the screw barrel (42) and the diameter of the screw (41) at the second end of the screw barrel wherein the snack food product exits the screw barrel is between about 0.4 mm and 1.6 mm, such as between about 0.4 mm and about 1.4 mm, between about 0.4 mm and about 1.0 mm, or between about 0.6 mm and about 1.0 mm e.g. about 0.8 mm. In one embodiment, the difference between the diameter of the screw barrel (42) and the diameter of the screw (41) is constant along the length of the screw barrel, or varies by less than 0.5 mm, e.g. less than 0.4 mm, less than 0.3 mm, less than 0.2 mm or less than 0.1 mm. If difference varies, it is typically greater at the first end than at the second end of the screw barrel i.e. at the second end of the screw barrel the gap between the screw and the barrel is smaller than at the first end of the screw barrel. In general, it will be appreciated from Figures 1 and 2 that the channel depth (31) of the screw decreases between the first and second ends of the screw barrel, but the screw clearance (33) (or screw root clearance (35) if the flight has tapered to approximately zero or zero) is typically constant, or varies to a small degree. This leads to the volume for the material within screw barrel decreasing between the first end and the second end of the screw barrel. As such, the screw and screw barrel are configured to engage such that the pressure applied to a material therebetween can be increased from the first end to the second end. In Figure 1, wherein the diameter of the screw (41) decreases between the first and second ends of the screw barrel, the diameter of the screw barrel (42) also decreases at the same or a similar rate, such that the screw clearance (33) (or screw root clearance (35) if the flight has tapered to approximately zero or zero) is constant, or varies by only a small amount. In Figure (2), the diameter of both the screw (41) and the screw barrel (42) remains constant. In both embodiments, the channel depth (31) of the screw decreases between the first end and the second end of the screw barrel; and the channel depth of the screw at the second end of the screw barrel where the snack food product exits the screw barrel is approximately zero, or zero. A screw press of use in one embodiment of the invention is shown in Figure 1, where it can be seen that between the first (11) and second (13) ends of the screw barrel, the screw root diameter is constant, but the height of the screw flight decreases. At the point where the snack food product exits the screw press at the second end of the screw barrel, the height of the screw flight has decreased to approximately zero, or zero. As such, the channel depth (31) of the screw has decreased to approximately zero, or zero. In this arrangement, the screw (7) decreases in diameter (41) between the first (11) and second (13) ends of the screw barrel. Having a screw in which the channel depth of the screw decreases between the first end and the second end of the screw barrel can also be achieved by having a screw (7) with constant diameter (41), but the channel depth (31) decreases between the first (11) and second (13) ends of the screw barrel because the screw root is tapered along its longitudinal axis (i.e. the diameter of the screw root (43) increases between the first and second ends of the screw barrel). An embodiment of the invention with this arrangement is shown in Figure 2, where it can be seen that the diameter of the screw root increases between the first and second ends of the screw barrel, while the height of the flight, and hence the channel depth (31) decreases. A 3D representation of a screw which is suitable for use in this embodiment is shown in Figure 4a, and a screw barrel is shown in Figure 4b. The screw shown in Figure 4a has constant diameter (41), but between the first and second ends of the screw barrel the screw root diameter (43) increases, while the channel depth (31) decreases (also as shown in Figure 2), such that at the second end of the screw, the flight has tapered to approximately zero, or zero. Thus, in one embodiment the screw root is tapered along its longitudinal axis, and in particular the diameter of the screw root at the second end of the screw barrel is larger than the screw root at the first end of the screw barrel. In another embodiment, the screw root has a uniform (constant) diameter. In one embodiment, the compression ratio of the screw press is between about 3:0 and about 4:0 e.g. about 3.85:0, wherein the compression ratio is the ratio of the maximum channel depth to the minimum channel depth. Compression ratios of high shear cooking extruders are typically about 4:1. In both of the embodiments shown in Figures 1 and 2, at the point snack food product exits the screw press, the channel depth is approximately zero or zero. The outlet through which the snack food product exits corresponds to the space between the screw root at the second end of the screw barrel, and the inner edge of barrel. As the screw root typically has a circular cross section, the outlet is typically a circular “donut” shape. This results in the snack food product exiting the screw press in hollow, cylindrical form. The hollow structure may be retained or partially retained in the snack food product. The difference between these hollow or partially hollow snack food products and those produced by typical extrusion cooking processes is that the hollow shape of the final product is imparted as the snack food product exits the screw barrel, rather than being formed via being forced through an extrusion die. The material as it exits the screw press can also be cut into a half tube. The screw press typically contains a single screw barrel, but embodiments using a twin-screw barrel are also envisaged. The process of the present invention differs from known extrusion processes for forming snack food products at least because the snackfood product is not passed through an extrusion die. In typical food extrusion cooking processes the extrusion die will shape the resulting food product, but also creates a pressure immediately before the die. The drop in pressure upon exiting the die impacts the nature of the resulting food product. The present inventors have found that if an extrusion die is affixed at or adjacent the outlet (19), the material as it exits the screw press becomes inflexible and hard, and clogs the die. When a food product is extruded through a die it is subjected to a longitudinal force (i.e. along the direction of the longitudinal axis of the extrusion barrel with a die at one end), and is not subjected to torque, or torque is the minor force whereas the longitudinal force is the major force. In contrast, when the snack food product of the present invention exits the screw press, torque is the major force compared to the longitudinal force. As such, the process of the present invention which does not involve the use of an extrusion die should not be considered as a typical food extrusion process. In one embodiment, the second end of the screw barrel does not comprise an extrusion die. The dimension of the outlet is dictated by the distance between the screw root (7a) and the inner surface of barrel (9), defined hereinabove as the screw root clearance (35). As shown in Figure 3, the flight width (37) is the width of the flight. The channel width (39) is the distance between two neighbouring flights. The channel width (39) can also be referred to as the screw pitch. In one embodiment, the rotatable screw has constant pitch. In one embodiment, the screw root clearance at the second end of the screw barrel wherein the snack food product exits the screw barrel is between about 0.2 mm and 0.8 mm, such as between about 0.2 mm and about 0.7 mm, between about 0.2 mm and about 0.5 mm, or between about 0.3 mm and about 0.5 mm e.g. about 0.4 mm. Having a screw root dimension within this range, together with the absence of an extrusion die, produces a snack food product with desirable organoleptic properties. In one embodiment, the food material is retained within the barrel for time period of between about 10 seconds and about 50 seconds, e.g. between about 10 seconds and about 25 seconds, e.g. around 15 seconds. As the snack food product exits the screw barrel it is typically in a flexible or semi-flexible state, but quickly hardens as it cools. In one embodiment, as the snack food product exits the outlet in the screw press it is cut into smaller segments e.g. using a guillotine, electric scissors or a rotary knife assembly. Once the snack food product has exited the screw press, and has optionally been cut into smaller segments, is can be subjected to a further processing step, such as a drying step. Thus, in one embodiment, the process of the invention further comprises step (c) subjecting the snack food product (of step b)) to a further processing step e.g. drying e.g. in an oven at a temperature of between about 50 °C and about 200 °C. In one embodiment, the snack food product is subjected to a further processing step to enhance the taste and / or flavour and / or appearance e.g. application of a flavouring agent or oil (wherein the oil may also be a flavouring agent) or a colouring agent (which may also be a flavouring agent). In one embodiment, once the snack food product is formed it is not subjected to any additional processing steps, other than optionally being cut into smaller segments. The screw barrel is typically heated during the process of the invention. In one embodiment, food material within the screw barrel reaches a temperature of between about 90 °C and about 300 °C, such as between about 90 °C and about 280 °C, between about 100 °C and about 280 °C, between about 125 °C and about 280 °C, between about 150 °C and about 280 °C, or between about 200 °C and about 280 °C. Without wishing to be bound by theory, the present inventors believe that the food material within the screw barrel reaches a temperature and pressure which is sufficient to cause at least a proportion of the carbohydrate in the starting food material to form a binder. This binder, together with the remaining food material within the barrel forms a cohesive flexible or semi-flexible material which undergoes a fusing process under the radial and / or circumferential pressure within the screw barrel, and upon exiting the screw barrel has been transformed into a snack food product. The food material within the screw barrel typically reaches a temperature of above 80 °C for over 6 seconds, providing a “kill-step” which removes or inactivates any dangerous pathogens present in the starting food material. In one embodiment, the screw press further comprising a computing device configured to automatically monitor, control, adjust and execute pre-programmed operations for preparing the snack food product (e.g. RPM and temperature). The starting food material used in the process of the invention comprises carbohydrate. In the context of the present invention, carbohydrates include sugars, oligosaccharides and polysaccharides. Sugars include monosaccharides and disaccharides. Examples of monosaccharides include glucose (also known as dextrose), fructose and galactose. Examples of disaccharides include sucrose, lactose and maltose. Oligosaccharides include dextrins (such as maltodextrins), raffinose, stachyose, fructo-oligosaccharides and verbascose. Polysaccharides include starch (including amylose, amylopectin and modified starches), and non-starch polysaccharides such as cellulose, hemicellulose, pectins and hydrocolloids (gums). Starch denotes a polymeric carbohydrate consisting of a large number of glucose units joined by glycosidic bonds. Starch is a polysaccharide comprising glucose monomers joined by alpha-1,4 linkages. The simplest form of starch is the liner polymer amylose, while amylopectin is the branched form. Derivatives of starch are included within “starch”. In one embodiment, carbohydrate is selected from the group consisting of sugars, oligosaccharides and polysaccharides, and mixtures thereof. In one embodiment, carbohydrate is selected from the group consisting of monosaccharides, disaccharides, oligosaccharides (in particular dextrins), starch, and mixtures thereof. In the context of the present invention “carbohydrate” is not intended to encompass polyols such as erythritol, xylitol, mannitol, sorbitol, lactitol, isomalt and maltitiol. In one embodiment, carbohydrate is selected from the group consisting of monosaccharides, disaccharides, oligosaccharides and polysaccharides, and mixtures thereof. In one embodiment, carbohydrate is selected from the group consisting of monosaccharides, disaccharides, oligosaccharides and starch, and mixtures thereof. In one embodiment, carbohydrate is selected from the group consisting of monosaccharides, disaccharides, dextrins and starch, and mixtures thereof. In one embodiment, carbohydrate is selected from the group consisting of glucose, fructose, galactose, sucrose, lactose, maltose, dextrins and starch, and mixtures thereof. In one embodiment, carbohydrate is starch. In one embodiment, carbohydrate is starch and / or monosaccharides and / or disaccharides. In one embodiment, in the context of the present invention, carbohydrate does not include fibre. In another embodiment, in the context of the present invention, carbohydrate includes fibre. Suitably, carbohydrate does not include fibre. In one embodiment, the starting food material contains at least 20 wt.% of carbohydrate, such as at least 25 wt.%, at least 30 wt.%, at least 35 wt.%, at least 40 wt.%, at least 45 wt.%, at least 50 wt.%, at least 55 wt.%, at least 60 wt.%, at least 65 wt.%, at least 70 wt.%, at least 75 wt.% or at least 80 wt.%. In one embodiment, the starting food material contains between about 20 wt.% and about 80 wt.% carbohydrate, such as between about 20 wt.% and about 75 wt.%, between about 20 wt.% and about 70 wt.%, between about 20 wt.% and about 65 wt.%, between about 20 wt.% and about 60 wt.%, between about 20 wt.% and about 55 wt.%, between about 20 wt.% and about 50 wt.%, between about 20 wt.% and about 45 wt.%, between about 20 wt.% and about 40 wt.%, between about 20 wt.% and about 35 wt.%, between about 20 wt.% and about 30 wt.%, between about 25 wt.% and about 80 wt.%, between about 25 wt.% and about 75 wt.%, between about 25 wt.% and about 70 wt.%, between about 25 wt.% and about 65 wt.%, between about 25 wt.% and about 60 wt.%, between about 25 wt.% and about 55 wt.%, between about 25 wt.% and about 50 wt.%, between about 25 wt.% and about 45 wt.%, between about 25 wt.% and about 40 wt.%, between about 25 wt.% and about 35 wt.%, between about 25 wt.% and about 30 wt.%, between about 30 wt.% and about 80 wt.%, between about 30 wt.% and about 75 wt.%, between about 30 wt.% and about 70 wt.%, between about 30 wt.% and about 65 wt.%, between about 30 wt.% and about 60 wt.%, between about 30 wt.% and about 55 wt.%, between about 30 wt.% and about 50 wt.%, between about 30 wt.% and about 45 wt.%, between about 30 wt.% and about 40 wt.%, between about 30 wt.% and about 35 wt.%, between about 35 wt.% and about 80 wt.%, between about 35 wt.% and about 75 wt.%, between about 35 wt.% and about 70 wt.%, between about 35 wt.% and about 65 wt.%, between about 35 wt.% and about 60 wt.%, between about 35 wt.% and about 55 wt.%, between about 35 wt.% and about 50 wt.%, between about 35 wt.% and about 45 wt.%, between about 35 wt.% and about 40 wt.%, between about 40 wt.% and about 80 wt.%, between about 40 wt.% and about 75 wt.%, between about 40 wt.% and about 70 wt.%, between about 40 wt.% and about 65 wt.%, between about 40 wt.% and about 60 wt.%, between about 40 wt.% and about 55 wt.%, between about 40 wt.% and about 50 wt.%, between about 40 wt.% and about 45 wt.%, between about 45 wt.% and about 80 wt.%, between about 45 wt.% and about 75 wt.%, between about 45 wt.% and about 70 wt.%, between about 45 wt.% and about 65 wt.%, between about 45 wt.% and about 60 wt.%, between about 45 wt.% and about 55 wt.%, between about 45 wt.% and about 50 wt.%, between about 50 wt.% and about 80 wt.%, between about 50 wt.% and about 75 wt.%, between about 50 wt.% and about 70 wt.%, between about 50 wt.% and about 65 wt.%, between about 50 wt.% and about 60 wt.%, between about 50 wt.% and about 55 wt.%, between about 55 wt.% and about 80 wt.%, between about 55 wt.% and about 75 wt.%, between about 55 wt.% and about 70 wt.%, between about 55 wt.% and about 65 wt.%, between about 55 wt.% and about 60 wt.%, between about 60 wt.% and about 80 wt.%, between about 60 wt.% and about 75 wt.%, between about 60 wt.% and about 70 wt.%, between about 60 wt.% and about 65 wt.%, between about 65 wt.% and about 80 wt.%, between about 65 wt.% and about 75 wt.%, between about 65 wt.% and about 70 wt.%, between about 70 wt.% and about 80 wt.%, between about 70 wt.% and about 75 wt.%, or between about 75 wt.% and about 80 wt.%. In one embodiment, the starting food material comprises, consists essentially of or consists of material selected from the group consisting of bread, corn chips, potato chips, fries, sweet pastries, pasta, rice, cookies, crackers, bagels, cake (including muffins), donuts, pizza crust, pies, pretzels, waffles, pancakes, popcorn and breakfast cereals, and mixtures thereof. All of these food materials have been subjected to a pre-processing step involving heating and / or drying, typically baking, frying, roasting, or extrusion cooking. Bread includes white, brown, granary, sourdough, seeded, mixed varieties and sweet breads such as brioche and flavoured brioche such as chocolate brioche. Bread is typically formed using a baking process. Bread typically contains around 50-75 wt.% starch. Whole slices, pieces or crusts of bread are of use in the process of the invention. Prior to use in the process of the invention, bread is optionally converted to breadcrumbs. Examples 1 and 2 describe the formation of snack food products comprising white bread and brown bread, respectively. In both cases the bread has previously undergone a baking process. Breads with a higher sugar and fat content such as brioche are also suitable for use in the process of the invention, as shown in Examples 3 and 4. Corn chips (which in the United Kingdom may also be known as “corn crisps’’) include tortilla chips, which have typically been baked or fried. Corn chips are typically consumed at room temperature. Potato chips (which in the United Kingdom may also be known as potato crisps) are thin slices of potato (or a thin deposit of potato paste) that has been deep fried, baked or air fired until crunchy. Potato chips are typically consumed at room temperature. Fries, also known as French fries (which in the United Kingdom may also be referred to as “chips”) are strips of potato which have typically been deep fried, baked or air fried. Fries are typically consumed immediately after cooking, while still warm. Pastries include croissant (including flavoured croissant such as almond croissant and chocolate croissant), pain au chocolate, pain au raisin, cinnamon buns, tartlets, Danish pastries and Baklava, and mixtures thereof. In each case, the pastry is formed at least in part from a pastry dough such as puff pastry, shortcrust pastry, filo pastry, flaky pastry or choux pastry. Brioche is described hereinabove as a sweet bread, but may also be described as a sweet pastry. Pasta and rice may be in dry, uncooked form, or alternatively a form that has undergone a cooking process (e.g. leftover pasta / rice waste from commercial cooking operations). Cooked pasta and cooked rice may need to undergo a drying process in order to meet the required maximum water content of 30 wt.% to be used as a starting food material in the process of the invention. Cookies (which may also be called biscuits in the United Kingdom) may be of a crunchy consistency or of a chewier consistency. In one embodiment, the starting food material comprises, consists essentially of or consists of plant-based material e.g. fruit and / or vegetables. Suitable vegetables include potato, cassava, yams, carrot, spinach, broccoli, parsnip, beetroot, onion, cucumber, butternut squash and sweet potato, and mixtures thereof. Suitable fruit includes apple, pineapple, tomato, blueberry, pear, strawberry, cherry, gooseberry, plum, nectarine, peach, apple pomace and other fruit pomace, grapes and mixtures thereof. The plant-based material may be used whole (subject to a size-reduction step), or just a part of the material may be used as starting food material, e.g. peelings, slivers or cuttings. In one embodiment, the starting food material comprises plant-based material which has been subjected to a heating and / or drying process. In Example 6 the starting food material comprises dried pineapple. The pineapple in this case was purchased ready-dried, but alternatively fresh pineapple could be used and subjected to a step of drying. In both cases, the starting food material has been subjected to a pre-processing step involving heating and / or drying. In one embodiment, the starting food material comprises defatted or partially defatted nuts and / or seeds (including oilcake), e.g. comprises defatted peanut flour and / or defatted sunflower seeds. Such defatted products are typically supplied in an already dried form, but will typically have been subjected to a heating step during or following fat (e.g. oil) extraction. In one embodiment, the starting food material comprises, consists essentially of potato starch. In one embodiment, the starting food material does not consist of starch, starch flour or flour in pure form, but the starting food materials themselves may include starch, starch flour or flour as ingredients. In one embodiment, the starting food material comprises a mixture of at least two different food materials. Before being used in the process of the invention, the starting food material has been previously subjected to a pre-processing step involving heating and / or drying. In one embodiment, the pre-processing step involving heating and / or drying is selected from the group consisting of baking, frying, roasting, extrusion cooking, pressing (including cold pressing), drying at a predetermined temperature and heated extraction, and mixtures thereof. Extrusion cooking in the context of the present invention refers to a process involving forcing soft, mixed food ingredients through a perforated extrusion die which is designed to produce food of a particular uniform shape. Heated extraction includes processes such as sugar and / or starch extraction prior to fermentation, or in the preparation of non-dairy milks. Certain starting materials such as fruit or vegetable peelings or pieces will require drying before being used as starting food material in the process of the invention. The drying temperature will depend on the nature of the food material being dried, and its initial moisture content. If the water content of the starting food material is too high (i.e. greater than 30 wt.%) a cohesive snack food product is not formed. In one embodiment, the starting food material has been dried at a temperature of 30 °C or above, such as 35 °C or above, 40 °C or above, 45 °C or above, 50 °C or above, 55 °C or above, 60 °C or above, 65 °C or above, 70 °C or above, 75 °C or above, 80 °C or above, 85 °C or above, 90 °C or above, 95 °C or above or 100 °C or above. Suitably, the starting material food material has been dried at a temperature of 75 °C or above. One purpose of the drying step can be to transform the food material into a form in which it can be manipulated into having a particular particle size. For example, certain raw fruit and / or vegetable material can be dried until it is in a form which can be ground into a breadcrumb type consistency. Also, it may be more practicable to store starting food materials in dry form. At this stage, water can be added back to the food material to form a starting food material of suitable consistency for use in the screw press, provided the overall water content of the starting food material is 30 wt.% or less. Where the leftover food / byproduct food to be upcycled is dry, the process of the invention can include a first moistening step to form the starting food material. In one embodiment, the starting food material is prepared by combining a food material selected from the group consisting of bread, corn chips, potato chips, fries, sweet pastries, pasta, rice, cookies, crackers, bagels, cake (including muffins), donuts, pizza crust, pies, pretzels, waffles, pancakes, popcorn, breakfast cereals, dried plant-material, defatted or partially defatted nuts and / or seeds (which have been optionally dried), and a liquid, suitably with 1-25% (weight / weight) of liquid. Any suitable liquid such as water, vinegar, fruit juice or milk (or a mixture thereof) can be used. In one embodiment, water and / or vinegar is added. Thus, in one embodiment, prior to being used as a starting material, the food material is subjected to a size-reduction step e.g. grinding. The particle size can be regulated by use of sieves. The size-reduction step is preceded by a drying step if required. In one embodiment, prior to being used as a starting material, the food material is subjected to de-oiling step. In one embodiment, all solid particles in the starting food material have a maximum dimension of 7 mm or less, such as 6 mm or less, 5 mm or less, 4 mm or less, 3 mm or less, 2 mm or less or 1 mm or less. In one embodiment, all solid particles in the starting food material have a maximum dimension of between about 0.5 mm and about 5 mm. The starting food material comprises 30 wt.% or less of water, referring to the water content after it has been subjected to the pre-processing step. In one embodiment, the starting food material comprises between about 0 wt.% and about 30 wt.% of water, such as between about 0 wt.% and about 25 wt.%, between about 0 wt.% and about 20 wt.%, between about 0 wt.% and about 15 wt.%, between about 0 wt.% and about 10 wt.%, between about 0 wt.% and about 5 wt.% of water, between about 1 wt.% and about 30 wt.% of water, between about 1 wt.% and about 25 wt.%, between about 1 wt.% and about 20 wt.%, between about 1 wt.% and about 15 wt.%, between about 1 wt.% and about 10 wt.%, between about 1 wt.% and about 5 wt.% of water, between about 2 wt.% and about 30 wt.% of water, between about 2 wt.% and about 25 wt.%, between about 2 wt.% and about 20 wt.%, between about 2 wt.% and about 15 wt.%, between about 2 wt.% and about 10 wt.%, between about 2 wt.% and about 5 wt.% of water, between about 3 wt.% and about 30 wt.% of water, between about 3 wt.% and about 25 wt.%, between about 3 wt.% and about 20 wt.%, between about 3 wt.% and about 15 wt.%, between about 3 wt.% and about 10 wt.%, between about 3 wt.% and about 5 wt.% of water, between about 4 wt.% and about 30 wt.% of water, between about 4 wt.% and about 25 wt.%, between about 4 wt.% and about 20 wt.%, between about 4 wt.% and about 15 wt.%, between about 4 wt.% and about 10 wt.%, between about 4 wt.% and about 5 wt.% of water, between about 5 wt.% and about 30 wt.%, between about 5 wt.% and about 25 wt.%, between about 5 wt.% and about 20 wt.%, between about 5 wt.% and about 15 wt.%, between about 5 wt.% and about 10 wt.%, between about 10 wt.% and about 30 wt.%, between about 10 wt.% and about 25 wt.%, between about 10 wt.% and about 20 wt.%, between about 10 wt.% and about 15 wt.%, between about 15 wt.% and about 30 wt.%, between about 15 wt.% and about 25 wt.%, between about 15 wt.% and about 20 wt.%, between about 20 wt.% and about 30 wt.% of water, between about 20 wt.% and about 50 wt.%, or between about 25 wt.% and about 30 wt.%. In one embodiment, the starting food material comprises between about 0 wt.% and about 40 wt.% of fat, such as between about 0 wt.% and about 30 wt.%, between about 0 wt.% and about 25 wt.%, between about 0 wt.% and about 20 wt.%, between about 0 wt.% and about 15 wt.%, between about 0 wt.% and about 10 wt.%, between about 0 wt.% and about 5 wt.%, between about 0.1 wt.% and about 40 wt.%, between about 0.1 wt.% and about 30 wt.%, between about 0.1 wt.% and about 25 wt.%, between about 0.1 wt.% and about 20 wt.%, between about 0.1 wt.% and about 15 wt.%, between about 0.1 wt.% and about 10 wt.%, between about 0.1 wt.% and about 5 wt.%, between about 0.2 wt.% and about 40 wt.%, between about 0.2 wt.% and about 30 wt.%, between about 0.2 wt.% and about 25 wt.%, between about 0.2 wt.% and about 20 wt.%, between about 0.2 wt.% and about 15 wt.%, between about 0.2 wt.% and about 10 wt.%, between about 0.2 wt.% and about 5 wt.%, between about 0.3 wt.% and about 40 wt.%, between about 0.3 wt.% and about 30 wt.%, between about 0.3 wt.% and about 25 wt.%, between about 0.3 wt.% and about 20 wt.%, between about 0.3 wt.% and about 15 wt.%, between about 0.3 wt.% and about 10 wt.%, between about 0.3 wt.% and about 5 wt.%, between about 0.4 wt.% and about 40 wt.%, between about 0.4 wt.% and about 30 wt.%, between about 0.4 wt.% and about 25 wt.%, between about 0.4 wt.% and about 20 wt.%, between about 0.4 wt.% and about 15 wt.%, between about 0.4 wt.% and about 10 wt.%, between about 0.4 wt.% and about 5 wt.%, between about 0.5 wt.% and about 40 wt.%, between about 0.5 wt.% and about 30 wt.%, between about 0.5 wt.% and about 25 wt.%, between about 0.5 wt.% and about 20 wt.%, between about 0.5 wt.% and about 15 wt.%, between about 0.5 wt.% and about 10 wt.% or between about 0.5 wt.% and about 5 wt.%. Fat is not an essential component of the starting material of the present invention, although in practice most starting food materials tend to have at least a small (e.g. de minimis) proportion of fat e.g. the process of the invention has been successfully carried out using carrot, which typically contains ~0.2 g of fat / 100 g. The starting food material may comprise additional components such as flavourings, preservatives, stabilizers, minerals, nutraceuticals and / or vitamins. The snack food product of the present invention suitably has a crisp texture. As mentioned above, when exiting the screw press the snack food product may have a softer, more flexible texture, but upon cooling (and optional drying) develops a crisp texture. A crisp texture may also be described as a “crunchy” texture, and denotes a food product showing at least one brittle fracturing event, where the fracturing is accompanied by the emission of a sound. The snack food product has crunch and mouthfeel that results in it being enjoyable to eat. This desirable texture may be achieved upon exiting the screw press (following cooling) or an additional drying step may be required. During the process of the invention, the product is not burned and contains no off-flavours. The snack food product is durable in the sense that it is resistant to breaking and / or deformation, despite being relatively thin and light in nature. It should be noted that in the context of the present application, when referring to a range of between about “AA” and about “BB”, the point values of AA and BB are intended to be included as possible values in the range. The word “comprise”, and variations such as “comprises” and “comprising” as used herein should be understood to mean the inclusion of the stated integer, step, group of integers or group of steps, but not to the exclusion of any other integer, step, groups of integers or group of steps. The word “consisting of’ as used herein limits the scope of the integer, step, group of integers or group of steps to the specified integer, step, groups of integers or group of steps. The word “consisting essentially of” as used herein limits the scope of the integer, step, group of integers or group of steps, and further integers, steps, groups of integers or groups of steps that do not materially affect the basic and novel characteristics of the invention. The invention embraces all combinations of indicated integers, steps, groups of integers or groups of steps recited above. All patents and patent applications referred to herein are incorporated by reference in their entirety. ABBREVIATIONS RPM revolutions per minute EXAMPLES The following Examples set forth preferred processes in accordance with the present invention. However, these examples are provided by way of illustration only and nothing therein should be taken as limiting the overall scope of the invention. In all Examples below a screw press with the following dimensions was used: Diameter of the screw (41): 20 mm. Channel depth (31) at the first end of the screw barrel: 3.85 mm. Channel depth (31) at the second end of the screw barrel: 0 mm. Length of screw from beginning of first flight to the end: 176 mm. Example 1 - Preparation of snack food product using white bread 100 g of dried white breadcrumbs (with composition set out in Table 1 below) were thoroughly mixed with 10 g of cold water. The resulting starting food material (with water content of 14-16 wt.%) was passed through the screw press at a temperature of 250 °C and RPM of 60. As the snack food product exited the screw press it was cut into pieces at 1.5 cm intervals. Table 1: White bread properties Ingredients: Wheat Flour [with Calcium, Iron, Niacin (B3) and Thiamin (B1)], Water, Yeast, Vegetable Oil (Rapeseed, Sustainable Palm), Salt, Flavouring, Soya Flour, Preservative: Calcium Propionate, Emulsifiers: E471, E481, Flour Treatment Agents: Ascorbic Acid (Vitamin C), E920 (Vegetarian), water 5-8%. Particle Size: No. 60 sieve (250 pm) The snack food product obtained using white bread is shown in Figure 5d. The photograph shows the snack food product after it has been cut into pieces. Example 2 - Preparation of snack food product using brown bread 100 g of dried brown breadcrumbs (with composition set out in Table 2 below) were thoroughly mixed with 10 g of cold water. The resulting starting food material (with water content of 14-16 wt.%) was passed through the screw press at a temperature of 250 °C and RPM of 60. As the snack food product exited the screw press it was cut into pieces at 1.5 cm intervals. Table 2: Brown bread properties Ingredients: Wholemeal Wheat Flour, Water, Yeast, Vegetable Oil (Rapeseed, Sustainable Palm), Salt, Wheat Gluten, Emulsifiers: E472e, E481, E471, Soya Flour, Preservative: Calcium Propionate, Flour Treatment Agent: Ascorbic Acid (Vitamin C), Water 5-8%. Particle Size: No. 60 sieve (250 pm) Example 3 - Preparation of snack food product using brioche (sweet bread) 100 g of dried brioche breadcrumbs (with composition set out in Table 3 below) were thoroughly mixed with 10 g of cold water. The resulting starting food material (with water content of 14-16 wt.%) was passed through the screw press at a temperature of 250 °C and RPM of 60. As the snack food product exited the screw press it was cut into pieces at 1.5 cm intervals. Table 3: Brioche properties Ingredients: Wheat Flour, Water, Sugar, Egg, Rapeseed Oil, Yeast, Wheat Gluten, Flavouring (Milk), Concentrated Butter (Milk), Salt, Dried Skimmed Milk, Rye Flour, Pea Protein, Emulsifier (Mono- and Diacetyl Tartaric Acid Esters of Mono- and Diglycerides of Fatty Acids), Rice Flour, Turmeric, Glucose Syrup, Flour Treatment Agent (Ascorbic Acid), Water 5-8% Particle Size: No. 60 sieve (250 pm) The snack food product obtained using brioche bread is shown in Figure 5c. The photograph shows the snack food product after it has been cut into pieces. Example 4 - Preparation of snack food product using chocolate brioche (sweet bread) 100 g of dried brioche breadcrumbs (with composition set out in Table 4 below) were thoroughly mixed with 20 g of cold water. The resulting starting food material (with water content of 21-23 wt.%) was passed through the screw press at a temperature of 250 °C and RPM of 60. As the snack food product exited the screw press it was cut into pieces at 1.5 cm intervals. Table 4: Chocolate brioche properties Ingredients: Wheat Flour, Chocolate Chips (8%) (Sugar, Cocoa Paste, Cocoa Butter, Flavouring, Emulsifier: Sunflower Lecithins), Sugar, Water, Invert Sugar Syrup, Rapeseed Oil, Egg, Flavourings, Creme Fraiche (Milk), Milk Chocolate Chips (1.5%) (Sugar, Dried Milk, Cocoa Butter, Cocoa Paste, Emulsifier: Sunflower Lecithins; Flavouring), Yeast, Wheat Gluten, Salt, Dried Milk, Emulsifiers (Mono- and Diglycerides of Fatty Acids, Sodium Stearoyl-2-Lactylate, Mono- and Diacetyl Tartaric Acid Esters of Mono- and Diglycerides of Fatty Acids), Milk Proteins, Deactivated Yeast, Colour (Beta Carotene), Water 5-8% Particle Size: No. 60 sieve (250 pm) A snack food product produced using a similar process but using a chocolate croissant as the starting food material (which did not require the addition of any water) is shown in Figure 5e. Example 5 - Preparation of snack food product using recovered potato chips 100 g of crushed potato chips (with composition set out in Table 5 below) were thoroughly mixed with 10 g of cold water. The resulting starting food material (with water content of 14-16 wt.%) was passed through the screw press at a temperature of 250 °C and RPM of 60. As the snack food product exited the screw press it was cut into pieces at 1.5 cm intervals. Table 5: Potato chip properties Ingredients: Potatoes, Vegetable Oils (Sunflower, Rapeseed, in varying proportions), Salt, Antioxidants (Rosemary Extract, Ascorbic Acid, Tocopherol Rich Extract, Citric Acid), Water 5-8% Particle Size: No. 35 sieve (500 pm) The snack food product obtained using potato chips is shown in Figure 5a. The photograph shows the snack food product being formed as it exits the screw barrel, and in this particular photo it has not been cut into pieces. A snack food product produced using a similar process but using Doritos™ as the starting food material (which did not require the addition of any water) is shown in Figure 5b. Example 6 - Preparation of snack food product using dried pineapple 100 g of ground dried pineapple (with composition set out in Table 6 below) was thoroughly mixed with 10 g of cold water. The resulting starting food material was passed through the screw press at a temperature of 200 °C and RPM of 60. As the snack food product exited the screw press it was cut into pieces at 1.5 cm intervals. Table 6: Dried pineapple properties Ingredients: Dried pineapple Grind Size: No. 30 sieve (595 pm) Example 7 - Preparation of snack food product using recovered waste potato 100 g of ground dried potato (with composition set out in Table 7 below) were thoroughly mixed with 15 g of cold water. The resulting starting food material (with water content of 17-20 wt.%) was passed through the screw press at a temperature of 150 °C and RPM of 60. As the snack food product exited the screw press it was cut into pieces at 1.5 cm intervals. Table 7: Potato crisp properties Ingredients: Whole dried potato, Water 5-8% Particle Size: No. 30 sieve (595 pm) Example 8 - Preparation of snack food product using waste parsnip 100 g of ground parsnip (with composition set out in Table 8 below) were thoroughly mixed with 10 g of cold water. The resulting starting food material (with water content of 14-16 wt.%) was passed through the screw press at a temperature of 175 °C and RPM of 60. As the snack food product exited the screw press it was cut into pieces at 1.5 cm intervals. Table 8: Potato crisp properties Ingredients: Whole dried parsnip, Water 5-8% Particle Size: No. 30 sieve (595 pm)

Claims

1. A process for manufacturing a snack food product, comprising the steps of:a) obtaining a starting food material comprising carbohydrate, whereinthe starting food material comprises 30 wt.% or less of water; and whereinthe starting food material has been subjected to a pre-processing step involving heating and / or drying;b) passing the starting food material through a screw press (3) comprising a screw barrel (5), whereinthe screw barrel (5) comprises a rotatable screw (7) within a barrel (9), the screw barrel (5) having a first end (11) and a second end (13); whereinthe starting food material enters the first end of the screw barrel (11) via an inlet (15) in the screw press, and the snack food product exits an outlet (19) in the screw press via the second end of the screw barrel; andthe channel depth (31) of the screw decreases between the first end and the second end of the screw barrel; andthe channel depth of the screw at the second end of the screw barrel where the snack food product exits the screw barrel is approximately zero.

2. The process according to claim 1, wherein the difference between the diameter of the screw barrel (42) and the diameter of the rotatable screw (41) is constant along the length of the screw barrel, or varies by less than 0.5 mm, e.g. less than 0.4 mm, less than 0.3 mm, less than 0.2 mm or less than 0.1 mm.

3. The process according to claim 1 or claim 2, wherein the second end of the screw barrel does not comprise an extrusion die.

4. The process according to any one of claims 1 to 3, wherein the screw root clearance at the second end of the screw barrel wherein the snack food product exits the screw barrel is between about 0.2 mm and 0.8 mm, such as between about 0.2 mm and about 0.7 mm, between about 0.2 mm and about 0.5 mm, or between about 0.3 mm and about 0.5 mm e.g. about 0.4 mm.

5. The process according to any one of claims 1 to 4, wherein the screw rotates at a speed of between about 30 RPM and about 250 RPM, such as between about 30 RPM and about 180 RPM, between about 40 RPM and about 100 RPM, between about 40 RPM and about 80 RPM, e.g. around 60 RPM.

6. The process according to any one of claims 1 to 5, wherein the food material is retainedwithin the barrel for time period of between about 10 seconds and about 50 seconds, e.g. between about 10 seconds and about 25 seconds, e.g. around 15 seconds.

7. The process according to any one of claims 1 to 6, wherein as the snack food product exits the outlet in the screw press it is cut into smaller segments.

8. The process according to claim 7, wherein once the snack food product has been cut into small segments it is subjected to a drying process.

9. The process according to any one of claims 1 to 8, wherein food material within the barrel reaches a temperature of between about 90 °C and about 300 °C.

10. The process according to any one of claims 1 to 9, wherein the pre-processing step involving heating and / or drying is selected from the group consisting of baking, frying, roasting, extrusion cooking, pressing (including cold pressing), drying at a predetermined temperature and heated extraction, and mixtures thereof.

11. The process according to any one of claims 1 to 10, wherein the starting food material contains at least 20 wt.% of carbohydrate, such as at least 25 wt.%, at least 30 wt.%, at least 35 wt.%, at least 40 wt.%, at least 45 wt.%, at least 50 wt.%, at least 55 wt.%, at least 60 wt.%, at least 65 wt.%, at least 70 wt.%, at least 75 wt.% or at least 80 wt.%.

12. The process according to any one of claims 1 to 10, wherein the starting food material contains between about 20 wt.% and about 80 wt.% carbohydrate, such as between about 20 wt.% and about 75 wt.%, between about 20 wt.% and about 70 wt.%, between about 20 wt.%and about 70 wt.%, between about 20 wt.% and about 65 wt.%, between about 20 wt.% andabout 60 wt.%, between about 20 wt.% and about 55 wt.%, between about 20 wt.% and about50 wt.%, between about 20 wt.% and about 45 wt.%, between about 20 wt.% and about 40wt.%, between about 20 wt.% and about 35 wt.%, between about 20 wt.% and about 30 wt.%,between about 25 wt.% and about 80 wt.%,between about 25 wt.% and about 75 wt.%,between about 25 wt.% and about 70 wt.%, between about 25 wt.% and about 60 wt.%, between about 25 wt.% and about 50 wt.%, between about 25 wt.% and about 40 wt.%, between about 25 wt.% and about 30 wt.%,between about 25 wt.% and about 65 wt.%, between about 25 wt.% and about 55 wt.%, between about 25 wt.% and about 45 wt.%, between about 25 wt.% and about 35 wt.%, between about 30 wt.% and about 80 wt.%,between about 30 wt.% and about 75 wt.%, between about 30 wt.% and about 70 wt.%,between about 30 wt.% and about 65 wt.%, between about 30 wt.% and about 60 wt.%,between about 30 wt.% and about 55 wt.%, between about 30 wt.% and about 50 wt.%,between about 30 wt.% and about 45 wt.%, between about 30 wt.% and about 40 wt.%,between about 30 wt.% and about 35 wt.%, between about 35 wt.% and about 80 wt.%,between about 35 wt.% and about 75 wt.%, between about 35 wt.% and about 70 wt.%,between about 35 wt.% and about 65 wt.%, between about 35 wt.% and about 60 wt.%,between about 35 wt.% and about 55 wt.%, between about 35 wt.% and about 50 wt.%,between about 35 wt.% and about 45 wt.%, between about 35 wt.% and about 40 wt.%,between about 40 wt.% and about 80 wt.%, between about 40 wt.% and about 75 wt.%,between about 40 wt.% and about 70 wt.%, between about 40 wt.% and about 65 wt.%,between about 40 wt.% and about 60 wt.%, between about 40 wt.% and about 55 wt.%,between about 40 wt.% and about 50 wt.%, between about 40 wt.% and about 45 wt.%,between about 45 wt.% and about 80 wt.%, between about 45 wt.% and about 75 wt.%,between about 45 wt.% and about 70 wt.%, between about 45 wt.% and about 65 wt.%,between about 45 wt.% and about 60 wt.%, between about 45 wt.% and about 55 wt.%,between about 45 wt.% and about 50 wt.%, between about 50 wt.% and about 80 wt.%,between about 50 wt.% and about 75 wt.%, between about 50 wt.% and about 70 wt.%,between about 50 wt.% and about 65 wt.%, between about 50 wt.% and about 60 wt.%,between about 50 wt.% and about 55 wt.%, between about 55 wt.% and about 80 wt.%,between about 55 wt.% and about 75 wt.%, between about 55 wt.% and about 70 wt.%,between about 55 wt.% and about 65 wt.%, between about 55 wt.% and about 60 wt.%,between about 60 wt.% and about 80 wt.%, between about 60 wt.% and about 75 wt.%,between about 60 wt.% and about 70 wt.%, between about 60 wt.% and about 65 wt.%,between about 65 wt.% and about 80 wt.%, between about 65 wt.% and about 75 wt.%,between about 65 wt.% and about 70 wt.%, between about 70 wt.% and about 80 wt.%,between about 70 wt.% and about 75 wt.%, or between about 75 wt.% and about 80 wt.%.

13. The process according to any one of claims 1 to 12, wherein the starting food material comprises material selected from the group consisting of bread, corn chips, potato chips, fries, sweet pastries, pasta, rice, cookies, crackers, bagels, cake (including muffins), donuts, pizza crust, pies, pretzels, waffles, pancakes, popcorn and breakfast cereals, and mixtures thereof.

14. The process according to any one of claims 1 to 13, wherein the starting food material comprises plant-based material which has been subjected to a drying process.

15. The process according to claim 14, wherein the plant-based material is fruit and / or vegetables.

16. The process according to claim 15, wherein the vegetable is selected from the group consisting of potato, cassava, yams, carrot, spinach, broccoli, parsnip, beetroot, onion, cucumber, butternut squash and sweet potato, and mixtures thereof.

17. The process according to claim 15 or claim 16, wherein the fruit is selected from the group consisting of apple, pineapple, tomato, blueberry, pear, strawberry, cherry, gooseberry, plum, nectarine, peach, apple pomace and other fruit pomace, grapes and mixtures thereof.

18. The process according to any one of claims 1 to 12, wherein the starting food material comprises defatted or partially defatted nuts and / or seeds.

19. The process according to claim 18, wherein the starting food material comprises defatted peanut flour and / or defatted sunflower seeds.

20. The process according to any one of claims 1 to 19, wherein the starting food material comprises a mixture of at least two different food materials.

21. The process according to any one of claims 1 to 20, wherein the starting food material comprises between about 0 wt.% and about 30 wt.% of water, such as between about 0 wt.% and about 25 wt.%, between about 0 wt.% and about 20 wt.%, between about 0 wt.% and about 15 wt.%, between about 0 wt.% and about 10 wt.%, between about 0 wt.% and about 5 wt.% of water, between about 2 wt.% and about 30 wt.% of water, between about 2 wt.% and about 25 wt.%, between about 2 wt.% and about 20 wt.%, between about 2 wt.% and about 15 wt.%, between about 2 wt.% and about 10 wt.%, between about 2 wt.% and about 5 wt.% of water, between about 5 wt.% and about 30 wt.%, between about 5 wt.% and about 25 wt.%, between about 5 wt.% and about 20 wt.%, between about 5 wt.% and about 15 wt.%, between about 5 wt.% and about 10 wt.%, between about 10 wt.% and about 30 wt.%, between about 10 wt.% and about 25 wt.%, between about 10 wt.% and about 20 wt.%, between about 10 wt.% and about 15 wt.%, between about 15 wt.% and about 30 wt.%, between about 15 wt.% and about 25 wt.%, between about 15 wt.% and about 20 wt.%, between about 20 wt.% and about 30 wt.% of water, between about 20 wt.% and about 50 wt.%, or between about 25 wt.% and about 30 wt.%.

22. A process according to any one of claims 1 to 21, wherein the starting food material comprises between about 0 wt.% and about 40 wt.% of fat, such as between about 0 wt.% and about 30 wt.%.5 23. A snack food product obtained according to a process as defined in any one of claims1 to 22.AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS:0? 12 24CLAIMS1. A process for manufacturing a snack food product, comprising the steps of:a) obtaining a starting food material comprising carbohydrate, wherein5 the starting food material comprises between about 2 wt.% and about 25 wt.% of water;and whereinthe starting food material has been subjected to a pre-processing step involving heating and / or drying;b) passing the starting food material through a screw press (3) comprising a screw barrel (5),10 whereinthe screw barrel (5) comprises a rotatable screw (7) within a barrel (9), the screw barrel (5) having a first end (11) and a second end (13); whereinthe starting food material enters the first end of the screw barrel (11) via an inlet (15) in the screw press, and the snack food product exits an outlet (19) in the screw press via the 15 second end of the screw barrel; andthe channel depth (31) of the screw decreases between the first end and the second end of the screw barrel; andthe channel depth of the screw at the second end of the screw barrel where the snack food product exits the screw barrel is approximately zero; and20 wherein the second end of the screw barrel does not comprise an extrusion die.

2. The process according to claim 1, wherein the difference between the diameter of the screw barrel (42) and the diameter of the rotatable screw (41) is constant along the length of the screw barrel, or varies by less than 0.5 mm.

253. The process according to claim 1 or claim 2, wherein the screw root clearance at the second end of the screw barrel wherein the snack food product exits the screw barrel is between about 0.2 mm and 0.8 mm.30 4. The process according to any one of claims 1 to 3, wherein the screw rotates at aspeed of between about 30 RPM and about 250 RPM.

5. The process according to any one of claims 1 to 4, wherein the food material is retained within the barrel for time period of between about 10 seconds and about 50 seconds.

6. The process according to any one of claims 1 to 5, wherein as the snack food product exits the outlet in the screw press it is cut into smaller segments.

7. The process according to claim 6, wherein once the snack food product has been cutinto small segments it is subjected to a drying process.5 8. The process according to any one of claims 1 to 7, wherein food material within thebarrel reaches a temperature of between about 90 °C and about 300 °C.

9. The process according to any one of claims 1 to 8, wherein the pre-processing step involving heating and / or drying is selected from the group consisting of baking, frying, roasting, 10 extrusion cooking, pressing (including cold pressing), drying at a predetermined temperature and heated extraction, and mixtures thereof.

10. The process according to any one of claims 1 to 9, wherein the starting food material contains at least 20 wt.% of carbohydrate.1511. The process according to any one of claims 1 to 9, wherein the starting food material contains between about 20 wt.% and about 80 wt.% carbohydrate.CMCM 12. The process according to any one of claims 1 to 11, wherein the starting food material '1““ 20 comprises material selected from the group consisting of bread, corn chips, potato chips, fries,CM sweet pastries, pasta, rice, cookies, crackers, bagels, cake (including muffins), donuts, pizzacrust, pies, pretzels, waffles, pancakes, popcorn and breakfast cereals, and mixtures thereof.

13. The process according to any one of claims 1 to 12, wherein the starting food material 25 comprises plant-based material which has been subjected to a drying process.

14. The process according to claim 13, wherein the plant-based material is fruit and / or vegetables.30 15. The process according to claim 14, wherein the vegetable is selected from the groupconsisting of potato, cassava, yams, carrot, spinach, broccoli, parsnip, beetroot, onion, cucumber, butternut squash and sweet potato, and mixtures thereof.

16. The process according to claim 14 or claim 15, wherein the fruit is selected from the 35 group consisting of apple, pineapple, tomato, blueberry, pear, strawberry, cherry, gooseberry, plum, nectarine, peach, apple pomace and other fruit pomace, grapes and mixtures thereof.

17. The process according to any one of claims 1 to 16, wherein the starting food material comprises defatted or partially defatted nuts and / or seeds.

18. The process according to claim 17, wherein the starting food material comprises 5 defatted peanut flour and / or defatted sunflower seeds.

19. The process according to any one of claims 1 to 18, wherein the starting food material comprises a mixture of at least two different food materials.10 20. The process according to any one of claims 1 to 19, wherein the starting food materialcomprises between about 2 wt.% and about 20 wt.% of water.

21. A process according to any one of claims 1 to 20, wherein the starting food material comprises between about 0 wt.% and about 40 wt.% of fat.0? 12 24Application No: GB2318694.3Examiner: Mr Brendan DonohoeClaims searched: 1-23Date of search: 30 May 2024Patents Act 1977: Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance X 1-6, 8-12, 14, 15 &20-23 US2023 / 0180815 Al (SUZUKI) - See whole document, note especially figures 3 &4 and paragraphs 0076-0079 &0095-0097. X 1,2, 4-12, 14-16 &20-23 CN103385534 A (SUN LEXIAN) - See whole document, note especially figures 1-3. X 1-12, 14- 16&20-23 US2013 / 0251872 Al (AXELROD) - See whole document, note especially figure 1. A - US2013 / 0069267 Al (LIU) - See especially figure 3 and paragraph 0021. A - JPS6155151A (MITSUI TOATSU CHEMICALS) - See especially figures 1-3.Categories:X Document indicating lack of novelty or inventive step A Document indicating technological background and / or state of the art. Y Document indicating lack of inventive step if P Document published on or after the declared priority date but combined with one or more other documents of same category. before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:Search of GB, EP. WO &US patent documents classified in the following areas of the UKCX :Worldwide search of patent documents classified in the following areas of the IPC____________ A21C; A21D; A23J; A23K; A23L; A23P; B28B; B29C; B30B_____________ The following online and other databases have been used in the preparation of this search report SEARCH - PATENTS; SEARCH - NPLInternational Classification:Subclass Subgroup Valid From A23P 0030 / 20 01 / 01 / 2016 B29C 0048 / 53 01 / 01 / 2019 B29C 0048 / 63 01 / 01 / 2019

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