The present invention relates to snack food pellets and to a method of manufacturing a plurality of expanded snack food pieces from the snack food peiiets. The present invention also relates to a kit of parts for carrying out the method of manufacturing the plurality of expanded snack food pieces from the snack food pellets.

The manufacture of snack food pellets is well known. Dried peiiets are produced by an extrusion process with a subsequent drying step. The pellets are then cooked, for example by frying in oil, which causes expansion the pellets to form an expanded snack food of a desired shape and configuration. Various compositions of snack food pellets are known.

Currently, such expanded snack foods are produced on an industrial scale and the expanded snack foods are packaged into individual packages which are then sold individually or in a multi-pack form.

There is a general need in the snack food art to provide consumers with new taste experiences associated with snack foods, for example which the consumer may perceive to be fresh and uniquely manufactured for that consumer.

Furthermore, there is a general need in the art to reduce transport costs and to ensure that snack foods are not damaged in transit before reaching the consumer.

The present invention aims at least partially to meet those needs.

The present invention accordingly provides a package comprising a measured dosage of snack food pellets sealed within a packaging, the pellets comprising a starch-based matrix which is expandable when subjected to heat during a cooking process.

The present invention further provides a method of manufacturing a plurality of expanded snack food pieces, the method comprising the steps of: i. providing a portion of a plurality of snack food pellets comprising a starch- based matrix which is expandable when subjected to heat during a cooking process;

ii. providing a cooking apparatus comprising a cooking chamber having an

annular sidewali, a base wall and an upper end with a dispensing opening, the cooking chamber defining a cooking cavity, and a plurality of vent openings disposed around a lower portion of the cooking chamber and opening into the cavity, a heater for heating air, and a fan mechanism for directing heated air into the cavity through the vent openings, the vent openings and the cooking chamber being configured to cause a vortex of heated air from the vent openings to be propelled upwardly towards the dispensing opening along an inner surface of the annular sidewall;

iii, disposing the portion of snack food pellets into the lower portion of the cooking chamber; and

iv. heating air using the heater and directing the heated air into the cavity through the vent openings, the heated air in the cavity cooking and expanding the snack food pellets thereby causing the expanded snack food pellets to enlarge in surface area and reduce in density, and the vortex of heated air from the vent openings propelling the expanded snack food pellets progressively upwardly towards the dispensing opening and causing the expanded snack food pieces to be dispensed out of the dispensing opening.

The present invention further provides a kit of parts for carrying out the method of the present invention, the kit comprising: i. a cooking apparatus comprising a cooking chamber having an annular sidewall, a base wall and an upper end with a dispensing opening, the cooking chamber defining a cooking cavity, and a plurality of vent openings disposed around a lower portion of the cooking chamber and opening into the cavity, a heater for heating air, and a fan mechanism for directing heated air into the cavity through the vent openings, the vent openings and the cooking chamber being configured to cause a vortex of heated air from the vent openings to be propelled upwardly towards the dispensing opening along an inner surface of the annular sidewall is substantially cylindrical; and

ii. a portion of a plurality of snack food pellets comprising a starch-based matrix which is expandable when subjected to heat during a cooking process.

Preferred features of all of these aspects of the present invention are defined in the dependent claims.

The preferred embodiments of the present invention can provide a novel way for consumers to produce expanded snack products in their own homes, using a known cooking apparatus and snack pellets packaged in a dosage format. The snack products can quickly and reliably be made on demand at home by the consumer, in an amount corresponding to an individual serving portion, typically from 15 to 40 g in weight.

The expanded snack food products are delivered warm from the cooking apparatus, which enhances the consumer experience and can enhance flavours and aromas associated with the snack food. The expanded snack products are produced on demand and so are freshly made, again the freshness enhancing the consumer experience, with the potential for increased flavours and aromas associated with the snack food.

Therefore consumers can be provided with new taste experiences associated with snack foods, which the consumer may perceive to be fresh and uniquely manufactured for that consumer.

Furthermore, since the package sold to the consumer contains pellets rather than expanded snack foods, the volume of the package can be reduced for any given weight of serving portion, and consequently this can reduce transport costs. Also, by providing pellets rather than a finished snack food to the consumer, this can ensure that the finished snack foods are not damaged in transit before reaching the consumer.

The cooking apparatus is available commercially as a home popcorn popper. Such units are widely available from multiple commercial consumer outlets. The cooking apparatus has been configured to cook and expand maize kernels to form and dispense popcorn.

The present invention is at least partly predicated on the finding by the present inventors that the same cooking apparatus currently sold as a home popcorn popper can reliably cook and expand snack food pellets and dispense the resultant expanded snack food products. The air flow velocity and temperature within the cooking chamber of the known cooking apparatus can be utilized to reliably cook and expand snack food pellets so that a uniformly cooked and expanded product is dispensed.

In order to make the expanded snack food products, the consumer places a serving portion of unexpended snack pellets into the cooking chamber of the cooking apparatus. When the cooking apparatus is switched on, the air heater and the fan mechanism are actuated. Heated air is directed into the cooking cavity within the cooking chamber. The air flow propels the pellets in a circular motion within the cooking cavity. The hot air causes the pellets to expand. The expansion increases the buoyancy of the pellets, causing the upward air flow to push the expanded pellets upwardly and out of the dispensing opening of the cooking apparatus, for example into a bowl ready for consumption.

The snack food pellets used in the present invention have a composition providing a propensity to expand in hot air. Furthermore, the physical characteristics, for example the dimensions, of the pellets before and after expansion, are compatible with their use in the cooking apparatus, for example the home popper machines described above. The snack food pellets may be provided with other product design features to improve eating quality, for example particular flavourings or texturizing components. The snack food pellets used in the present invention are provided in a consumer acceptable retail format, for example a packaging such as a bag or carton, typically hermetically sealed, which is compatible with a retail sales environment.

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:

Figure 1 schematically illustrates a perspective view of a partly open package comprising a measured dosage of snack food pellets for subsequent forming into expanded snack food pieces in accordance with an embodiment of the present invention;

Figure 2 schematically illustrates a perspective view of a snack food pellet for subsequent forming into an expanded snack food piece in accordance with an embodiment of the present invention;

Figure 3 schematically illustrates an end view of an expanded snack food piece produced from the snack food pellet of Figure 2;

Figure 4 schematically illustrates a perspective view of a cooking apparatus for manufacturing a plurality of expanded snack food pieces from snack food pellets in accordance with another embodiment of the present invention; and

Figure 5 schematically illustrates a perspective side cross-sectional view of the cooking chamber in the cooking apparatus of Figure 4.

Referring to Figure 1 of the accompanying drawings, a package 2 comprising a measured dosage of snack food pellets 4 sealed within a packaging 6. The packaging 6 comprises a polymeric bag 10, having a side seal 12 and two opposed end seals 14, 16, which is conventionally used to package snack food chips. The contents may be hermetically sealed within the bag, optionally within a controlled atmosphere, for example a low oxygen atmosphere. The bag is shown partly opened to illustrate the contents of the snack food pellets 4 therein.

The packaging is selected based upon the retail format in which the pellets are to be supplied to the customer. For retail consumption, the pellets may be supplied in a bag, for example a conventional formed, filled and sealed packaging currently used for snack food chips, or a box. The measured dosage may be suitable for a single product serving, for example from 15 to 40 g. Alternatively, the measured dosage may be a larger amount from which multiple individual servings can be provided, defined either by weight or by volume, for example a cup-full. Such a multiple serving package may be re-sealable for later use.

Referring also to Figure 2 of the accompanying drawings, the pellets 4 comprise a starch- based matrix 18 which is expandable when subjected to heat during a cooking process. The snack food pellet typically comprises from 70 to 99 wt% of a starch-based matrix 18. The starch-based matrix 18 comprises at least one starch, optionally a blend of starches or starch- containing components, which may be derived from a cereal, such as wheat, oats, barley, rice or maize, or a vegetable, optionally potato, or any mixture thereof. Other starch ingredients or sources may be used. The starch-based matrix may optionally various additional constituents such as colouring and/or flavouring components, sugars, raising agents, salts, emulsifiers, fats/oils, humectants, acids, bases, proteins, fibres, dairy ingredients, texture modifiers, acidity regulators or any combination thereof.

The composition of the pellets may incorporate one or more functional components, either within the body of the snack pellet, or applied as a coating to the snack pellet, to impart specific characteristics to the product. For example, a flavour or aroma component may be provided to release an aroma during the hot air expansion of the pellet. The composition may be formulated to improve the expansion characteristics, for example to achieve a higher expansion, providing a lighter texture to the consumer and/or a more consistent expansion. Other components may be added to provide a delivery of flavour, a delivery of colour or other visual effects, or a modification of texture, for example by providing a crunchy outer shell to the expanded piece. As is known in the art, the snack pellet may be formulated to provide a desired moisture content, salt content, starch content, etc. Typically, the starch- based matrix has a moisture content of from 8 to 14 wt% based on the weight of the starch- based matrix. Although as described herein the packaged pellets 4 have particular utility when employed in a cooking apparatus in which the pellets 4 are cooked and expanded using hot air, the packaged pellets 4 may alternatively be employed in any other cooking step which may comprise frying, baking or microwaving, any of which may also be used in a home or domestic environment.

A single layer pellet 4 may be provided. This may have any desired two-dimensional shape. The shape may be regular or irregular, and geometric, for example rectangular, or representational, for example representing a leaf.

Preferably, the starch-based matrix in the pellets 4 is in the form of at least one layer 24 which has a thickness of at least 0.5 mm, typically from 0.5 to 4 mm.

In one embodiment, the pellets 4 are shaped to include at least one substantially planar surface 20. For example, the pellets 4, or surfaces thereof, may be substantially planar, which for the avoidance of doubt includes surfaces having some regular or irregular curvature.

Preferably, the pellets 4 are shaped to include at least one perforation 22 through at least one layer 24 of the starch-based matrix composition. There may be an array of perforations 22 through at least one layer 24 of the starch-based matrix composition. The perforations 22 may have any desired two-dimensional shape.

In one embodiment, as shown in Figure 2 the pellets 4 are shaped to form at least two adjacent layers 24a, 24b joined together along at least a part of the respective circumferential edges 26. The two adjacent layers 24a, 24b are typically arranged to form an expanded snack food piece 28 as shown in Figure 3 having a hollow three-dimensional shape with upper and lower layers 32a, 32b connected by a circumferential joint 30. The layers 32a, 32b include perforations 36. The layers 32a, 32b are spaced apart at the centre of the expanded snack food piece 28 to define a hollow void 34. For example, the expanded snack food piece 28 may comprise a pillow shape, as shown in Figure 3 which is produced from the pellet 4 of Figure 2. Alternatively, the expanded snack food piece 28 may comprise a pyramidal shape or a spherical shape, or any other three dimensional shape.

The pellets 4 typically have a density of from 0.15 to 0.6 g/cm ³ . The pellets 4 typically have a mass of from 0.2 to 1.5 g. In some embodiments, the pellets 4 include a largest surface having an area of at least 0.8 cm ² , for example from 1 to 5 cm ² . Typically, the pellets 4 have a total surface area, including external and internal surfaces, of from 2 to 12 cm ² . Typically, the pellets 4 have a maximum dimension of 5 cm. In some embodiments, the pellets 4 include two opposite major surfaces having a length and a width, and the ratio between the length and the width ranges from 1 : 1 to 12: 1.

The pellet 4 is formulated and structured to expand during the hot air cooking process and to thereby achieve sufficiently increased buoyancy, in a flow of air, of the expanded snack food piece 28 to enable the air flow within the cooking cavity reliably to carry the expanded product to the top of the cavity for dispensing out of the opening, as described in further detail below.

Typical properties of pellets in accordance with the present invention which are well suited to hot air expansion are (i) a starch composition with a high degree of gelatinisation and (ii) an open pellet structure to allow rapid thermal energy transfer from the pellet surface to the interior of the pellet.

Starch gelatinisation is dependent upon the relative amounts of amorphous and crystalline starch within the starch-based matrix of the pellet. These amounts may be measured using Fourier Transform Infrared Spectroscopy (FTIR), a technique known in the art. A higher proportion of amorphous starch generally corresponds with a generally higher expansion in the hot air cooking conditions.

In some embodiments, the starch-based matrix includes a crystalline fraction and an amorphous fraction, wherein the weight ratio of the crystalline fraction to the amorphous fraction is from 0.15 to 0.67, optionally from 0.17 to 0.60. In some embodiments, the starch- based matrix includes a crystalline fraction and an amorphous fraction, and the amorphous fraction comprises from 50 to 90 wt%, optionally from 60 to 85 wt%, of the combination of the crystalline fraction and an amorphous fraction. Such a high amorphous fraction can provide increased expansion of the pellet.

The starch-based matrix may be formulated so as to be adapted to expand by from 50 to 500 % when forming the expanded snack food piece.

The starch matrix can achieve the desired crystalline and amorphous fractions by providing a single starch-containing component or a blend of different starch components. A starch component having a high degree of amorphous starch can be a highly gelatinised starch produced by a preliminary cooking step.

Furthermore, in order to achieve expansion during cooking, it is important that the starch- based matrix in the pellet melts at the cooking temperature in order for the starch to be in the molten state and therefore capable of readily swelling at that temperature. The starch-based matrix in the pellet should have a melting temperature (Tm) which is lower than the temperature reached by the pellet through the air-flow heating process.

Typically, the starch-based matrix has a melting temperature of from 50 to 70 °C, optionally from 50 to 60 °C.

The pellets are manufactured using an extruder, as generally known in the art of snack food manufacture. The pellets have a composition to provide a desired colour; flavour; starch; starch-containing ingredient; level of starch gelatinization; internal porosity; open volume; density; moisture content; and shape, or any combination of any two or more thereof. It is known generally how to control these parameters in the manufacture of snack food pellets.

The shape and dimensions of the pellets, together with the composition of the pellets which determines the degree of expansion of the pellet during cooking, primarily determine the shape and dimensions of the expanded snack food pieces produced from the pellets. The pellet may be shaped and dimensioned to provide any desired shape and dimensions to the resultant expanded snack food piece using shape and dimension selection techniques well known to those skilled in the snack food art.

Typically, the pellets are adapted to form an expanded snack food piece having a density of from 0.05 to 0.1 g/cm ³ . The pellets may be adapted to form an expanded snack food piece having a mass of from 0.2 to 1.2 g.

The pellets are typically adapted to form an expanded snack food piece in which the largest surface has an area of from 2 to 16 cm ² . The expanded snack food piece may have a maximum dimension of 7 cm. In some embodiments, the pellets are adapted to form an expanded snack food piece which includes two opposite major surfaces having a length and a width, and the ratio between the length and the width ranges from 1 : 1 to 16: 1.

In some embodiments, the pellets are adapted to form an expanded snack food piece which includes a cross-section having a maximum dimension of 60 mm.

In some embodiments, the pellets are adapted to form an expanded snack food piece having a volume which is from 50 to 500 % larger than the volume of the pellet.

Although one aspect of the present invention provides packaged pellets for use in any cooking method, in another aspect the present invention provides a particular cooking method to cook and expand the pellet.

In the method of manufacturing a plurality of expanded snack food pieces in accordance with one aspect of the present invention, a cooking apparatus is provided.

Referring to Figures 4 and 5, the cooking apparatus 50 comprises a cooking chamber 52 having an annular sidewall 54, a base wall 56 and an upper end 58 with a dispensing opening 60. The dispensing opening 60 is located in a removable lid 61 , which is shown transparent in Figure 4, or between the lid 61 and a housing 63 of the cooking apparatus 50. The cooking chamber 52 defines a cooking cavity 62. A plurality of vent openings 64 is disposed around a lower portion 66 of the cooking chamber 52. The vent openings 64 open into the cavity 62. The cooking apparatus 50 also comprises a heater 68 for heating air, and a fan mechanism 70 for directing heated air, via a manifold 65, into the cavity 62 through the vent openings 64.

Preferably, the cavity 62 is substantially cylindrical. The cavity 62 may have a height of from 5 to 10 cm and an average width of from 4 to 10 cm. Typically, the cavity 62 has a volume of from 250 to 3250 cm ³ .

Typically, the dispensing opening 60 has an area of from 12.5 to 40 cm ² . The dispensing opening 60 preferably has a minimum transverse dimension of 5 cm.

The vent openings 64 and the cooking chamber 52 are configured to cause a vortex 72 of heated air from the vent openings 64 to be propelled upwardly towards the dispensing opening 60 along an inner surface 74 of the annular sidewall 54. The direction of air flow from each vent opening 64 is inclined downwardly, as shown by arrow A, for example at an angle of from 30 to 60 degrees to the horizontal. The air flow from each vent opening 64 is substantially tangential to the sidewall 54 and is deflected back from the base wall 56 and then is directed upwardly along the annular sidewall 54.

The cumulative air flows from the plural vent openings 64 form an upwardly moving vortex 72 of air, which propels any solid pellets in a circular motion around the lower portion 66, and then helically upwardly along the annular sidewall 54 once the density of the pellet material is sufficiently reduced as a result of expansion, with corresponding increase of the surface area against which the air flow is directed, to provide sufficient uplift to permit the air flow to blow the expanded piece to the top of the cooking cavity 62 and then out of the dispensing opening 60.

A portion of a plurality of the snack food pellets 4 comprising a starch-based matrix which is expandable when subjected to heat during the cooking process is disposed into the lower portion 66 of the cooking chamber 52,

Air is heated using the heater 68. Typically, the air is heated to a temperature of at least 150 °C, typically from 150 to 185 °C, more typically from 160 to 180 °C.

The fan mechanism 70 directs the heated air into the cavity 62 through the vent openings 64. Typically, the heated air is directed into the cavity 62 through the vent openings 64 at a total an air flow velocity of from 2 to 5 m/s, optionally from 3 to 4 m/s.

The heated air in the cavity 62 cooks and expands the snack food pellets 4. Such expansion causes the expanded snack food pellets to enlarge in surface area and reduce in density.

The vortex 72 of heated air from the vent openings 64 propels the expanded snack food pellets progressively upwardly towards the dispensing opening 60. Eventually, when the expanded snack food pieces 28 attain the required lower density, the upward flow of air causes the expanded snack food pieces 28 to be dispensed out of the dispensing opening 60.

The cooking time, and consequently the residence time, of the snack food pellets 4 within the cooking chamber 52 is determined by the properties of the snack food pellets 4 and the resultant expanded snack food pieces 28, and by the air flow velocity and temperature within the cooking chamber 52. There is no need to provide a cooking timer in the cooking apparatus 50.

The timing of the dispensing and the residence time within the cavity 62 is controllable by selecting appropriate properties of the snack food pellets 4 and the resultant expanded snack food pieces 28 for a given range of air flow velocities and cooking temperatures of the cooking apparatus 50, for example currently commercially available home popcorn poppers, to ensure reliable dispensing of the expanded snack food pieces 28 only after they have been fully cooked. The relatively low cooking temperature minimises the possibility of burning or scorching of the expanded snack food pieces 28.

The cooking apparatus and the portion of a plurality of snack food pellets may be provided as a kit of parts for carrying out the method of manufacturing a plurality of expanded snack food pieces from the pellets. The portion of snack food pellets is preferably provided in the form of a package, as described above. The package may comprise written instructions how to use the snack food pellets packaged therein in a method of manufacturing a plurality of expanded snack food pieces in the cooking apparatus.

In the cooking method of the present invention hot air is used to cook and expand the pellet. Air is much less efficient at transferring thermal energy into the pellet interior than hot oil, which is the conventional medium for cooking pellets to form expanded snack food pieces. Consequently, in order to compensate for the reduced energy transfer from the hot air, the pellet is structured so as to be sufficiently thin in section so that the pellet presents a high surface area to allow heat energy to enter the pellet at a high level of thermal efficiency.

Such a structure may be achieved by providing that the smallest pellet dimension is less than a few millimetres. For simple pellet structures, for example sticks or substantially flat two- dimensional structures, the smallest pellet dimension can be determined by a simple measurement of the thinnest dimension. Other pellet structures can comprise a more complex perforated or lattice sheeted structure, often with multiple sheets layered on top of each other. In such cases, the thickness of thinnest strands within the perforated/lattice structure may be determined to constitute the smallest pellet dimension.

Typically, when the pellet, or the expanded snack food piece, is in the form of a three dimensional shape, preferably the pellet is structured to provide a substantially uniform exposure to the air flow throughout the pellet. This can provide a uniform expansion, and avoid the edges being burned or scorched and the middle of the pellet being unexpended.

Preferably, the pellet shape and dimensions can provide that the heat transfer on outside surfaces, and if present on inside pellet surfaces, is substantially equal, so the expansion of the pellet tube is controlled and regular. It is preferred to structure the pellet so that the air impacts all surfaces of the expanding pellet in a turbulent flow, and that any inside surfaces of the pellet are not subjected alternatively to a laminar air flow, A laminar flow would transfer heat from the flowing air at a lower rate than a turbulent flow, and so a combination of both turbulent and laminar air flows over different surfaces of the pallet may result in unequal heat transfer, and consequently unequal expansion. If the pellet is configured to expand to form a hollow snack piece, perforations in the starch-based matrix layers may be shaped and dimensioned to permit turbulent air flow to enter into the interior of the expanding snack pellet.

Correspondingly, if the pellet comprises a single layer, then a relatively thick layer may exhibit an unexpanded centre portion. This problem may be overcome by providing perforations through the layer to permit the heated air to contact the centre of the layer though the sides of the perforations in the through-thickness of the layer.

The pellet thickness is also selected to provide that opposite sides of a starch-based matrix layer are likely to be heated substantially uniformly, to minimise the potential for differential heating on opposite sides of the pellet which could cause undesired warping of the expanded pellet. This may be overcome by providing a thin layer and/or by providing perforations through the layer thickness.

The pellet shape and dimensions, together with thickness, which together are associated with the mass of the pellet, are selected to provide a controlled change in density of the pellet which causes a controlled uplift by the air flow prior to dispensing. If the mass is too low, and/or if the surface area presented to the air flow is too large, the pellet may be dispensed prematurely. Typically, pellets thinner than 0.5 mm tend to be too light and may exhibit excessive buoyancy, and may whirl rapidly around inside the cooking cavity and break upon collision with the sidewall.

The pellet properties may be determined using reasonable trial and error to be utilisabie in a cooking apparatus having a typical range for both the air flow velocity and the cooking temperature for such apparatus.

The pellets and the resultant expanded pieces preferably have parameters to enable them reliably to proceed through the expansion and dispensing steps of the cooking process.

Some parameters tend to affect the buoyancy of the unexpanded pellet, which should be low enough to prevent pellets exiting the cooking cavity before the desired degree of expansion has been achieved: the pellet bulk density, the surface area of the largest face of the pellet; and the weight per pellet.

Some parameters tend to affect the buoyancy of the expanded snack food piece, which should be high enough to ensure that the expanded product exits the cooking cavity: the expanded product bulk density; the surface area of the largest face of the expanded product; and the weight per expanded product piece.

Some parameters tend to affect the ability of the expanded pieces being capable of exiting the dispensing opening at the top of the coking cavity: the dimensions, typically the two smallest dimensions defining the minimum cross-section, must be small enough to enable the piece to fit through the opening.

In a modified packaging, the pack may be devised to have a primary function to deliver the pellets to the consumer in a retail format, and also a secondary function in which the package is subsequently converted, after dispensing pellets into the cooking apparatus, into a bowl or other receptacle to catch the expanded snack food pieces from the dispensing opening and for use as a serving bowl.

Various other modifications to the present invention will be readily apparent to those skilled in the art.