WO2023075614A1

WO2023075614A1 - High moisture meat analogues – products and processes

Info

Publication number: WO2023075614A1
Application number: PCT/NZ2022/050134
Authority: WO
Inventors: Jade GRAY; Allan Hardacre; Alex RADLEY
Original assignee: Off-Piste Limited
Priority date: 2021-10-29
Filing date: 2022-10-28
Publication date: 2023-05-04

Abstract

A product and process for the formation that may be used to provide plant-based protein for animal, and in particular human, nutrition. The present invention also relates to extrusion technology and products and processes that relate thereto. The invention relates to high moisture meat analogues (HMMAs) prepared by extrusion using a unique extrusion die and the extrusion die itself. The unique extrusion die may be a long extrusion die which tapers from a first height to a second height, and reverse tapers from a first width to a second width to allow for a roughly constant flow rate through the die. The extrusion die may preferably only cool the extruded material over part of the die to help maintain a reduced viscosity and maintain a desirable flowrate.

Description

High Moisture Meat Analogues - products and processes

Field of Invention

The present invention relates to the field of animal nutrition, primarily but not limited to human nutrition. In particular, the invention relates to products and processes for their formation that may be used to provide plant-based protein. The present invention also relates to extrusion technology and products and processes that relate thereto. In specific embodiments the invention relates to high moisture meat analogues (HMMAs) prepared by extrusion using a unique extrusion die and the extrusion die itself.

Background to the Invention

While animal meat has been a staple human food source for thousands of years, primarily as a source of protein, growing trends in human health and consumer behaviour have called for a diversified diet. Personal reasons for reducing animal meat consumption include:

• health reasons - for example increased processed or red meat consumption has been correlated with increased incidence of certain cancers;

• ethical considerations - including animal welfare;

• environmental sustainability - including the impacts of intensive animal farming.

Many consumers now consciously strive to source a growing proportion of their protein needs from non-animal protein sources - indeed the twentieth and twenty-first centuries have seen a rise in health and consumer trends towards plant-based diets.

While there is now a growing range of plant-based dietary choices available to source protein from, there is some consumer resistance in shifting from animal meat to plant-based options in part due to an underlying desire (perhaps primal desire) for a meaty sensorial experience (including similar taste, appearance, and/or texture). To date very few, if any, plant based offerings can faithfully reproduce the sensorial experience (taste, appearance, and/or texture) of consuming animal meat.

For some segments of consumers, such a difference in sensorial experience (taste, appearance, and/or texture) is not problematic and can even be desirable. However for a great many people, being able to consume plant-based protein that provides a meaty sensorial experience (taste, appearance, and/or texture) is strongly desired. While advances have been made using soy protein in creating a desirable meaty texture, soy is an allergen and hence inedible for a substantial proportion of the world's population.

The global demand for protein is expected to rise by 20% from 2018 to 2025, in part driven by a significant Asian population having access to greater consumer choice.

Associated with meeting the growing demand for plant-based protein, is the desire to offer such protein in a readily consumable form. Such readily consumable forms are highly desired by certain segments in the consumer market - such as those people participating in physical activities (including: activities without access to refrigeration like hiking; and intense activities like gym users); and those people desiring a ready to use meal ingredient.

Object of the Invention

Singularly, or in addition to any one or more other objects, it is an object of the invention to provide a plant-based protein source having a desirable meat-like sensorial experience.

Singularly, or in addition to any one or more other objects, it is an object of the invention to provide a plant-based protein source having a desirable meat-like texture.

Singularly, or in addition to any one or more other objects, it is an object to provide a plant-based protein source having a desirable meat-like appearance.

Singularly, or in addition to any one or more other objects, or in addition to any other object, it is an object to provide a plant-based protein source having a desirable meat-like taste, such as flavour profile.

Singularly, or in addition to any one or more other objects, it is an object to provide a plant-based protein source in a readily consumable form.

Alternatively, it is an object of the invention to at least provide the public with a useful choice. Summary of the Invention

The present invention relates to high moisture meat analogue (HMMA) products, and methods and apparatus for the manufacture of same. In simple terms, HMMA products are meat alternatives made using high moisture extrusion.

In a first aspect the invention provides a mixture for use in the formation of a high moisture meat analogue (HMMA) product, the mixture including:

(i) plant-based protein including pea protein and/or faba bean protein;

(ii) sugar;

(iii) lipid; and

(iv) starch.

Preferably the plant-based protein will be included at between 15-95% w/w of the mixture Preferably the sugar will be a monosaccharide.

In a second aspect the invention provides a high moisture meat analogue (HMMA) product produced by extrusion of water and a mixture including:

(i) plant-based protein including pea protein and/or faba bean protein;

(ii) sugar;

(iii) lipid; and

(iv) starch.

Preferably the plant-based protein will be included at between 15-95% w/w of the mixture.

Preferably the sugar will be a monosaccharide.

In a third aspect the invention provides an extrusion process for making a high moisture meat analogue (HMMA) product, the process including the step of: a) introducing into an extruder a mixture including:

(i) plant-based protein including pea protein and/or faba bean protein;

(ii) sugar;

(iii) lipid; and

(iv) starch; b) combining the mixture with water; c) extruding the combined mixture and water through an extruder die.

In a fourth aspect the invention provides a high moisture meat analogue extrusion produced by the extrusion process of the third aspect.

In a fifth aspect the invention provides an extruder die for incorporation in an extruder, the extruder die having an elongate internal channel, wherein the elongate internal channel includes: i) an entrance aperture for receiving material mixed in the extruder; ii) an exit aperture through which extrudate exits the extruder; and iii) a longitudinal flow path between the entrance aperture and the exit aperture such that the material mixed in the extruder moves under pressure along the longitudinal flow path in use, wherein the elongate internal channel has, along at least a portion of the longitudinal flow path, a cross sectional profile that: i) tapers from a first height to a second height; and ii) reverse-tapers from a first width to a second width, such that the area of the cross sectional profile in the at least portion differs by no more than 50%.

In a sixth aspect the invention provides an extrusion process for making a high moisture meat analogue (HMMA) product, the process including the step of: a) introducing into an extruder a mixture including:

(i) plant-based protein including pea protein and/or faba bean protein;

(ii) sugar;

(iii) lipid; and

(iv) starch; b) combining the mixture with water; c) extruding the combined mixture and water through an extruder die, the extruder die having an elongate internal channel, wherein the elongate internal channel includes: i) an entrance aperture for receiving material mixed in the extruder; ii) an exit aperture through which extrudate exits the extruder; and iii) a longitudinal flow path between the entrance aperture and the exit aperture such that the material mixed in the extruder moves under pressure along the longitudinal flow path in use, wherein the elongate internal channel has, along at least a portion of the longitudinal flow path, a cross sectional profile that: i) tapers from a first height to a second height; and ii) reverse-tapers from a first width to a second width, such that the area of the cross sectional profile in the at least portion differs by no more than 50%.

In a seventh aspect the invention provides a high moisture meat analogue extrusion produced by the extrusion process of the sixth aspect.

Further aspects of the invention, which should be considered in all its novel aspects, will become apparent to those skilled in the art upon reading of the following description which provides at least one example of a practical application of the invention.

Brief Description of the Drawings

One or more embodiments of the invention will be described below by way of example only, and without intending to be limiting, with reference to the following drawings, in which:

Figure 1 shows an exemplary extruder (die not shown) that may be used in the present invention, and having a plurality of heating elements that can be used to modulate the temperature of the water and mixture described herein as it passes through the extruder.

Figure 2 shows an exemplary extruder die attached to the extruder shown in Figure 1. The Extruder die is provided with hosing that allows a fluid (such as water) to be used to cool the extruder die.

Figure 3(a) shows an exemplary vessel (a steam jacketed vessel) that may be used to marinate the extrudate which is shown in the vessel in Figure 3(b).

Figure 4 shows an exemplary extruder die of the present invention in which the die is formed from two substantial halves being secured to eachother. Nominally, and purely for distinction purposes, the two substantial halves may be referred to as the bottom half and the top half, although this nomenclature is arbitrary and the orientation may be varied at will without altering the shape of the longitudinal flow path. The extruder die in this case may optionally be provided with plates (as shown) to further modulate the longitudinal flow path, although this are generally absent.

Figure 5 shows an isometric view of the internal view of the bottom part of the exemplary extruder die shown in Figure 4. Figure 6 shows an isometric view of the external view of the bottom part of the exemplary extruder die shown in Figure 4.

Figure 7 shows an end view of the entrance aperture end of the bottom part of the exemplary extruder die shown in Figure 4.

Figure 8 shows an end view of the exit aperture end of the bottom part of the exemplary extruder die shown in Figure 4

Figure 9 shows a plan view of the internal view of the bottom part of the exemplary extruder die shown in Figure 4.

Figure 10 shows a plan view of the external view of the bottom part of the exemplary extruder die shown in Figure 4.

Figure 11 shows a side view of the bottom part of the exemplary extruder die shown in Figure 4.

Figure 12 shows an isometric view of the internal view of the top part of the exemplary extruder die shown in Figure 4.

Figure 13 shows an isometric view of the external view of the top part of the exemplary extruder die shown in Figure 4.

Figure 14 shows an end view of the entrance aperture end of the top part of the exemplary extruder die shown in Figure 4.

Figure 15 shows an end view of the exit aperture end of the top part of the exemplary extruder die shown in Figure 4

Figure 16 shows a plan view of the internal view of the top part of the exemplary extruder die shown in

Figure 4. Figure 17 shows a plan view of the external view of the top part of the exemplary extruder die shown in

Figure 4.

Figure 18 shows a side view of the top part of the exemplary extruder die shown in Figure 4.

Figure 19 shows extrudate exiting the exit aperture of the extruder die of the invention. In this embodiment the extruder die is provided with cutting members (in this case, three wires) that enable the extrudate to be provided in four strips.

Figure 20 shows the extrudate shown in Figure 19 that has been further portioned in a transverse direction (to the longitudinal flow path) to create strips of a desired dimension, such as for drying and/or marination and/or packaging.

Figure 21 shows extrudate both before and after marination/drying. Figure 21 (a) shows four strips of extrudate that have each been torn to show fibre development. Figure 21 (b) shows the same four strips of Figure 21 (a) that have been further subject to marination and drying. Figure 21 (c) shows the same four strips of Figure 21 (b) over which have been drawn lines with angles to the transverse direction being shown (L to R - 14°; 0°; 15°; and 38°). The transverse direction here is taken from Figure 21 (a) which shows that the fresh extrudate piece second from the left has a roughly symmetrical convex/concave fibre profile coming out of the extruder die.

Figure 22 shows an isometric view of the internal view of the bottom part (50) of a second exemplary extruder die.

Figure 23 shows an end view of the entrance aperture end of the bottom part (50) of a second exemplary extruder die.

Figure 24 shows an end view of the exit aperture end of the bottom part (50) of a second exemplary extruder die.

Figure 25 shows a plan view of the internal view of the bottom part (50) of a second exemplary extruder die. Figure 26 shows a plan view of the external view of the bottom part (50) of a second exemplary extruder die.

Figure 27 shows an isometric view of the internal view of the top part (66) of a second exemplary extruder die.

Figure 28 shows an end view of the entrance aperture end of the top part (66) of the exemplary extruder die shown in Figure 4.

Figure 29 shows an end view of the exit aperture end (56) of the top part (66) of a second exemplary extruder die.

Figure 30 shows a plan view of the internal view of the top part (66) of a second exemplary extruder die.

Figure 31 shows a photograph of a device (80) that may be positioned at the exit of an extruder die so that extrudate is fed between two textured rollers (one shown as 82), in this case bearing wire bristles.

Figure 32 shows a photograph of the second exemplary extruder die (86) of the invention.

Detailed Description of the Invention

The inventors have discovered that a HMMA product can be produced providing an excellent meat-like sensorial experience through the use of an optimal formulation and/or an optimal extrusion process incorporating the use of a unique extruder die.

Protein source

The mixture used to make the HMMA as described herein includes plant-based protein including pea protein and/or faba bean (broad bean) protein. Preferably the plant-based protein will include both pea protein and faba bean protein. Oat and Mung bean proteins are far less preferable, providing the product with a softer texture that is not as fibrous and having a slightly bitter flavour.

Preferably the plant-based protein will consist of pea protein and/or faba bean protein. Still more preferably the plant-based protein will consist of both pea protein and faba bean protein. Preferably the plant-based protein will be present at 15-95% (w/w) of the non-water ingredients in the mixture used to make the HMMA, such as 50-95% (w/w), such as 65-95% (w/w), such as 70-95% (w/w), such as 80-95% (w/w), such as 80-92% (w/w), such as 80-89% (w/w), such as 82-88% (w/w).

Preferably the HMMA as described herein will contain no substantial quantity of soy protein, such as less than 5% (w/w), such as less than 2% (w/w). More preferably the HMMA as described herein will contain 0% soy protein.

Where present, the pea protein is preferably included at 20-92% (w/w), such as 30-80% (w/w) of the non-water ingredients in the mixture used to make the HMMA, such as 45-75% (w/w), preferably 65- 75% (w/w), still more preferably 66-71% (w/w), such as 66-69% (w/w) such as 67-68% (w/w). A preferred source of pea protein may be sourced from Yantai T. Full Biotech, China or from Davis Food Ingredients. Otherwise, pea protein isolate can be used, but is less preferable than pea protein concentrate.

Where present, the faba bean protein is preferably included at 10-80% (w/w), such as 15-75% (w/w) of the non-water ingredients in the mixture used to make the HMMA, such as 15-35% (w/w), preferably 16-20% (w/w), still more preferably 16-19% (w/w). Faba bean protein may be sourced from Ingredion.

It will be understood that the protein used in the present invention may not be 100% protein by chemical analysis. For example, pea protein powder (an example of a "pea protein" referred to herein) may be constituted as: 75% protein; 5% carbohydrate; 5% fibre; 7.5% fat; 1% salt. By way of further example, faba bean powder (an example of a faba bean protein referred to herein) may be constituted as: 60% protein; 12% carbohydrate; 13% fibre; 3.5% fat; very low sodium. Variations in the chemical constituents of the pea protein and/or faba bean protein are contemplated within the scope of the invention. As described herein the pea protein and/or faba bean protein may include at least 50% protein by chemical analysis, such as at least 60% protein by chemical analysis, preferably at least 70% protein by chemical analysis, more preferably at least 75%.

On these bases, the protein from chemical analysis that may be provided by pea protein may be: 10-46% (w/w), such as 15-40% (w/w) of the non-water ingredients in the mixture used to make the HMMA, such as 22.5-37.5% (w/w), preferably 32.5-37.5% (w/w), still more preferably 33-35.5% (w/w), such as 33- 34.5% (w/w) such as 33.5-34% (w/w) - for the at least 50% protein by chemical analysis level noted above. Further values for each of the other levels (such as at least 60% protein by chemical analysis, preferably at least 70% protein by chemical analysis, more preferably at least 75%) may be derived likewise.

Similarly, the protein from chemical analysis that may be provided by faba bean protein may be: 5-40% (w/w), such as 7.5-37.5% (w/w) of the non-water ingredients in the mixture used to make the HMMA, such as 7.5-17.5% (w/w), preferably 8-10% (w/w), still more preferably 8-9.5% (w/w) - for the at least 50% protein by chemical analysis level noted above. Further values for each of the other levels (such as at least 60% protein by chemical analysis, preferably at least 70% protein by chemical analysis, more preferably at least 75%) may be derived likewise

Other ingredients

Typically the lipid will be plant derived, such as:

• an edible oil (liquid at room temperature). Examples of suitable oils include canola, coconut, corn, olive, peanut, safflower, soy, and sunflower oil. Olive oil is particularly preferred; or

• an edible fat (solid at room temperature). An example of a suitable fat includes cocoa butter.

The lipid is preferably included at 1-10% (w/w) of the non-water ingredients in the mixture used to make the HMMA, such as 1-5% (w/w), preferably 2-4% (w/w), still more preferably about 3-4% (w/w), such as about 3.6% (w/w).

While animal derived lactose can be used, typically the sugar will be plant derived, such as glucose (dextrose), fructose, or sucrose. Glucose in the form of dextrose monohydrate is particularly preferred. Sugar may be included at less than 20% (w/w), such as 1-10% (w/w) of the non-water ingredients in the mixture used to make the HMMA, such as 3-8% (w/w), preferably 4-6% (w/w), still more preferably about 5% (w/w). It was surprisingly found that the incorporation of sugar in the formulation had a positive effect on fibre formation whereby the texture and consistency of the product were improved as it exited the extruder die. The incorporated sugar can be in the form of pure sugar, or can also be an edible sugary substance such as a syrup such as golden syrup or fruit juices (fructose). The addition of apple juice concentrate (fructose) also resulted in good fibre formation. In such cases the amount of the sugary substance to be incorporated can be calculated based on the concentration of sugar within that substance and the above ranges. For example, if a syrup having 50% sugar content is used, then the amount of that syrup may be 2-20% (w/w) of the non-water ingredients in the mixture used to make the HMMA, such as 6-16% (w/w), preferably 8-12% (w/w), still more preferably about 10% (w/w). It has been found that monosaccharides are particularly preferred sugars, and preferred over the use of disaccharides. Accordingly, still more preferably the sugar content can be calculated based on the level of monosaccharides in the sugary substance, such that the monosaccharide content as a percentage of the non-water ingredients in the mixture used to make the HMMA may be Sugar may be less than 20% (w/w), such as 1-10% (w/w), such as 3-8% (w/w), preferably 4-6% (w/w), still more preferably about 5% (w/w). One example of a sugary substance used in the invention is molasses, which may contain: sucrose (29% of total carbohydrates); glucose (12%); and fructose (13%). Notably, many commercial jerky products have a high sugar content (>20%), which may not be desirable for a number of consumers. Without wishing to be bound by theory, it is believed that the incorporation of sugar in the non-water ingredients may have a positive effect due to the lubricating effect provided by the sugar on the material as it travels through the die. Such lubrication may result in the material being extruded travelling at uniform velocity across the width of the extruder die. Such uniform velocity, in turn, would result in uniform cooling of the material and hence more uniform texture. Such enhancements were observed more with glucose and less with sucrose.

Starch may be used from a range of sources, although corn (maize) starch is preferred. Such starch can be Avon Starch, from NZ Starch. Starch may be included at 1-10% (w/w) of the non-water ingredients in the mixture used to make the HMMA, such as 1-5% (w/w), preferably 2-4% (w/w), still more preferably about 3% (w/w).

Yeast extract may optionally be used in the present invention, including as:

• a component of the mixture for use in the formation of a high moisture meat analogue (HMMA) product. Where present yeast extract may be added at 1-10% (w/w) of the non-water ingredients in the mixture used to make the HMMA, such as 1-5% (w/w), preferably 2-4% (w/w), still more preferably about 3% (w/w);

• a component of the high moisture meat analogue (HMMA) product produced by extrusion of water and the mixture;

• a food flavouring, such as a component of a marinade.

Yeast is available in many forms, although preferred forms include yeast extract, brewer's yeast and nutritional yeast. The term "yeast" as used herein includes a reference to each of these products, and any other food ingredients being derived from yeast. Preferably, the term "yeast" refers to yeast extract, brewer's yeast and nutritional yeast. Still more preferably, the term "yeast" refers to nutritional yeast. Yeast extracts consist of the cell contents of yeast without the cell walls and an example of a yeast extract is from Springarom, which is understood to be a yeast extract-based flavour. Brewer's yeast generally refers to whole yeast - being the one-celled fungus Saccharomyces cerevisiae. Nutritional yeast is a food additive generally made from a single-celled organism, Saccharomyces cerevisiae, which is grown on molasses and then harvested, washed, and dried with heat to kill or "deactivate" it.

Where present yeast extract may be added at 1-10% (w/w) of the non-water ingredients in the mixture used to make the HMMA, such as 1-5% (w/w), preferably 2-4% (w/w), still more preferably about 3% (w/w). It has been found that the inclusion of yeast extract is particularly beneficial in improving the sensorial experience (particularly taste) of the HMMA product. It has been found that the yeast extract reduces the pea notes and/or increases the meatiness of the product.

Salt may optionally be used as a flavour enhancer and/or water activity modulator to resist spoilage. Salt may be included at 0.1-5% (w/w) of the non-water ingredients in the mixture used to make the HMMA, such as 0.3-2% (w/w), such as about 1% (w/w).

Additional fibre (soluble or insoluble) may be incorporated in the non-water ingredients used to make the HMMA. An example is pea fibre. Where included, such fibre may be included at 1-5% (w/w) of the non-water ingredients in the mixture used to make the HMMA, such as 1-3% (w/w), such as about 2% (w/w).

Ideally the water activity of the dehydrated product of the invention should be less than 0.80, such as 0.75 or less, such as 0.70 or less. It is believed that such water activity provides the safest product in terms of food safety as microbes don't generally grow below 0.85. A desired water activity may be achieved through a drying process. It has been found that reducing water activity too low may also negatively impact on the sensorial experience (such as texture) of the product. It has been found that a water activity of around 0.68 has good shelf life but is significantly tougher in texture than a water activity of about 0.72 which is significantly more appealing sensorially. Optimal Formulation

After significant research, the optimal formulation discovered by the inventors is as follows:

* Pea protein preferably contains greater than 80% protein as prepared using a Dry Extraction Method.

# Faba Bean protein preferably contains about 64% protein content.

Another exemplary formulation is as follows:

Water Content

Water is typically combined with the non-water ingredients after those ingredients have been added to the extruder. The water may comprise between 45 and 65% (w/w) of the total weight of the extruded product; such as between 50% (w/w) and 60% (w/w); such as approximately 50% (w/w); such as approximately 56% (w/w). Sensorial Experience

As used herein, the term "texture" can refer to structure and/or chew profile. The structure of the product may be fibrous, including such that the product possesses a plurality of fibres that are substantially aligned. The assessment of texture can be qualitative and/or quantitative. Qualitatively the consumer can assess texture against prior experience, or in side-by-side trials comparing meat and the HMMA product of the invention. Preferably the HMMA/extrudate exhibits one or more of the following characteristics: it breaks down to a fine, soft fibrous texture in the mouth during chewing, similar to chicken breast meat or good quality steak.; it is not rubbery or hard to chew; and/or it is not biscuity or mushy. One method of qualitatively assessing the texture, such as the fibre alignment, is for the observer to tear the HMMA product along the grain and observe the fibre structure. Such fibre alignment is most notable in a HMMA product that has undergone marination and drying as there is colour differentiation between the external and internal fibres due to the marination process.

Quantitatively, a substantial number of the fibres may be substantially aligned, such as at least 20%, at least 30%, at least 40%, or at least 50% , preferably at least 60%, such as at least 70% or at least 75% of fibres that are substantially aligned. The term "substantially aligned" as used herein refers to an arrangement of protein fibers such that a significantly high percentage of the fibers are contiguous to each other at less than about a 45° angle when viewed in a horizontal plane. Preferably the fibre alignment is observed in the transverse direction (transverse to the longitudinal flow path of the extruder die as described herein). It is believed that alignment in the longitudinal direction often results in a more rubbery product.

A method for analyzing protein fibre arrangements is described below. Samples are fixed for 8-24 hours, then successively placed in a sucrose gradient (10% sucrose for 1 hour, 20% sucrose for 1 hour, and 30% sucrose overnight), before being placed in OCT (Optimal Cutting Temperature compound) and frozen in isopentane. The OCT blocks are sliced on a microtome along either longitudinal or transversal axes, the slices are transferred to cold glass slides, and the sections are stained with PAS (Periodic Acid-Schiff) to identify polysaccharides and gly-colipids, or with H&E (Hematoxylin & Eosin) to identify protein. The slices are imaged with a Nikon Eclipse E600 upright microscope with phase contrast, epifluorescence, and bright field capabilities (Nikon Corp., Japan) at 20x and 200x magnification to determine the presence of protein fiber networks similar to those present in animal meat. Interspersed open spaces are filled with polysaccharides and glycolipids. Texture may also include a reference to other mechanical properties of the HMMA/extrudate. Preferably the HMMA/extrudate: breaks into pieces when stretched in the longitudinal direction; has minimal recoil length after being stretched in the transverse direction using a tensile test; and/or breaks between fibres during a penetration test as opposed to localised bulging which is a characteristic rubbery products.

Preferably the texture of the product can include one or more of the following characteristics:

• relatively compact fibres;

• rustic appearance - resembling a natural meat like substance;

• chewy when bitten;

• firm when bitten; and/or

• breaks down in the mouth.

Preferably the texture of the product includes 2 or more, such as 3 or more, such as 4 or more, such as five of the characteristics.

As used herein "appearance" refers to the visual appearance of the product. While assessment of the appearance using analytical tools such as microscopy is contemplated, typically appearance will be assessed by a human (such as the consumer), unmagnified. Desirable appearance may be characterised as being visibly roughened, and may include surface cracks and/or a semi-porous outer layer. Surface porosity may be tested using a liquid retention method. A quantity of the HMMA/extrudate to be tested is soaked in a known liquid for a period of time. Preferably the liquid is a flavorous marinade and the uptake is at least 6% of the weight of the product after soaking for 2 hours at 70 °C.

It has been found that there are four main factors that affect the sensorial experience (including taste, appearance, and/or texture) of the product:

• the non-water ingredients;

• the water content;

• the processing temperature profile; and

• the product throughput rate (and hence processing time).

It has been found that varying the quantities of the non-water ingredients from the proportions described in the optimal formulation above led to the following changes in sensorial experience:

Some information regarding the sensorial experience provided by various ingredient mixtures has been shown below in the Formulation Studies Table.

The Extruder

As used herein "extruder" takes its standard meaning and typically refers to an instrument designed to use pressure to force a material through an aperture of an element referred to as a die. In that process, typically a fragmented material (such as a particulate material, slurry, etc) is introduced at the end of the extruder opposite to the die, and pressure is exerted on the fragmented material so that it exits the die ideally as a unitary material such as a substantially homogenous continuous mass, having a cross sectional dimension approximating the cross sectional profile of the die. The continuous mass may then be subject to one or more processes such as slicing, chopping, etc to achieve products of desired dimensions.

Preferably the extruder used in the present invention is a twin screw extruder. Examples of preferred extruders are the Clextral B21 twin screw extruder and the Clextral D32 twin screw extruder. The rotation of the two screws will substantially uniformly mix the fragmented material introduced to the extruder and generate pressure and also some heat.

The extruder may be configured to be supplied with additional heat. Such additional heat may be supplied using one or more heating blocks arranged along the length of the extruder in one or more regions. It has been found that the sensorial experience (taste, appearance, and/or texture) of the extruded product is enhanced when a plurality of heating blocks are used wherein the heating block(s) closest to the extruder die is maintained at a high temperature than the heating block furthest from the die. Preferably a series of three of more heating blocks is used to provide a temperature gradient that decreases from the end of the extruder closest to the die to the end of the extruder furthest from the die.

An example of an arrangement of heating blocks along a Clextral B21 extruder is shown in Figures 1 and 2. Seven heating blocks are arranged along the length of the extruder barrel, each heated to a set temperature depending on their position with lower temperatures at the powder feed end and higher temperatures further along the barrel. The temperatures of the seven heating blocks were kept at 20, 50, 80, 110, 150, 170, and 150 °C respectively, although other temperatures and combinations of temperatures are envisaged. Typically there will be a general trend to provide a temperature gradient that decreases from the end of the extruder closest to the die to the end of the extruder furthest from the die and closest to the powder feed end.

The Extruder Die

A large variety of dies are available for use with extruders. However, prolonged research has identified a particular extruder die design that enables the generation of HMMA products having an optimal sensorial experience.

The particular extruder die has an elongate internal channel, wherein the elongate internal channel includes: i) an entrance aperture for receiving material mixed in the extruder; ii) an exit aperture through which extrudate exits the extruder; and iii) a longitudinal flow path between the entrance aperture and the exit aperture such that the material mixed in the extruder moves under pressure along the longitudinal flow path in use, wherein the elongate internal channel has, along at least a portion of the longitudinal flow path, a cross sectional profile that: i) tapers from a first height to a second height; and ii) reverse-tapers from a first width to a second width, such that the area of the cross sectional profile in the at least portion differs by no more than 50%. As used herein "taper" refers to a reduction/decrease in a dimension from a first position to a second position along the longitudinal flow path (wherein the first position is more proximate the entrance aperture than the second position).

As used herein "reverse-taper" refers to an expansion/increase in a dimension from a first position to a second position along the longitudinal flow path (wherein the first position is more proximate the entrance aperture than the second position).

It has been found that the particular tapering/reverse-tapering shape allows for the flow rate to remain roughly constant along the at least portion of the extruder die, while at the same time enhancing the appearance and texture (in particular) of the extruded product. The tapering in the height and/or reverse-tapering in the width dimensions may independently be linear or non-linear. Examples of nonlinear tapers include curved tapers, or irregular tapers (including stepped). Preferably the taper will be linear or curved. Still more preferably the taper will be linear. Examples of non-linear reverse-tapers include curved reverse-tapers, or irregular reverse-tapers (including stepped). Preferably the reversetaper will be linear or curved. Still more preferably the reverse-taper will be linear.

As described herein, for clarity the cross sectional profile has been described with reference to height and width. These dimensions are transverse to the longitudinal flow path. It will be understood that rotation of the extruder die may invert these positions with reference to the horizontal plane, for example. To be clear, the invention contemplates all such orientations of the tapers and reverse-tapers. Generally the width dimension will be at right angles to the height dimension. Generally the precise identification of the height or width dimension will be independent of the position of these dimensions to the horizontal plane. That said, it may be preferable for the extrudate to exit the extruder die such that its horizontal dimension is greater than its vertical dimension, such that it can be easily portioned into strips.

As defined, in the extruder die the "area of the cross sectional profile in the at least portion differs by no more than 50%". The area of the cross sectional profile in the at least portion may preferably differ by no more than 35%, more preferably by no more than 25%, and still more preferably by no more than 20%, even more preferably by no more than 10%, such as by no more than 5%. Preferably there is no change in the area along the longitudinal flow path, or the area increases or decreases along the longitudinal flow path by no more than 5%. Without wishing to be bound by theory it is believed that keeping the area of the cross sectional profile in this range provides enhanced sensorial experience to the extruded product. In some particularly preferred embodiments there is substantially no change in the area along the longitudinal flow path in the at least portion - that is, the area of the cross-sectional profile should remain consistent in the at least portion. In some further particularly preferred embodiments there is a decrease of no more than 4% in the area along the longitudinal flow path in the at least portion - that is, the area of the cross-sectional profile should remain consistent in the at least portion.

The dimensions of the extruder die may be chosen to be relative to the size of the extruder being used and/or the flow rate, for example. Variables that may be varied include: overall length; amount of cooling; cross sectional area sized to the extruder; and throughput rate. In some non-limiting embodiments, the extruder die is 1400 mm in length.

In some non-limiting embodiments (hereinafter referred to as the "A embodiments") the channel tapers from a height of about 10 mm to about 4 mm in at least a portion of the longitudinal flow path and/or the channel reverse-tapers from a width of about 50 mm to about 120 mm in at least a portion the channel. Thus when the channel tapers AND reverse tapers as noted immediately above the cross- sectional area of the die longitudinal flow path decreases, such as in a carefully controlled manner, from about 500 mm² to about 480 mm².

In some non-limiting embodiments (hereinafter referred to as the "B embodiments") the channel tapers from a height of about 10 mm to about 5 mm in at least a portion of the longitudinal flow path and/or the channel reverse-tapers from a width of about 60 mm to about 150 mm in at least a portion the channel. Thus when the channel tapers AND reverse tapers as noted immediately above the cross- sectional area of the die longitudinal flow path increases, such as in a carefully controlled manner, from about 600 mm² to about 750 mm².

Without wishing to be bound by theory, the B embodiments (which have a larger cross sectional area proximate the entrance and the exit aperture) are believed to provide better throughput that the A embodiments, such as at extruder startup.

The dimensions of the channel may then further vary along the longitudinal flow path. It will be understood that these dimensions may be varied while still keeping within the scope of the presently described invention. As used herein, the term "about" in relation to a numerical value refers to an acceptable variation in that numerical of, for example, up to +/- 10%, such as up to +/- 5%, such as up to +/- 2%.

The "at least a portion" of the longitudinal flow path in which the tapering occurs may include the whole length of extruder die, or only a portion of the extruder die. In this way, the channel may include parallel-sided regions and tapering regions. The channel may only include tapering regions. The channel may include tapering regions of differing tapers, including combinations of a plurality of each of linear and/or non-linear tapering regions. In some embodiments, the channel includes two tapering regions, each of different linear tapers. In some embodiments, the channel includes two tapering regions, each of different linear tapers such that the two tapering regions combined extend along the entire longitudinal flow path.

It will be understood that such extruder dies are able to be used to subject the material being extruded to heating and/or cooling. It has further been found that cooling the material being extruded is desired to enhance the sensorial experience for the HMMA. It has been found that as the extruder die temperature increases, the fibrous meat-like properties of the extruded material decline and the product transitions towards a firmer more rubbery texture as is cools. Without wishing to be bound by theory, it is believed that the enhancements is achieved in part because the extrudate undergoes minimal expansion upon exiting the exit aperture of the extruder die. Such cooling can be effected by withdrawing heat from the cooling die. While heat will naturally be withdrawn by the working environment, where that environment is colder than the cooling die, accelerating the removal of heat from the material being extruded is preferred. Accelerating the removal of heat can be achieved through a number of processes, including the use of a jacket on the cooling die through which a fluid may flow such that heat can be transferred from the material being extruded, to the extruder die, and subsequently to the fluid flow. Such a jacket may make use of a distribution manifold to enhance the even distribution of the cooling water into the jacket so as to enhance the consistency of the extrudate. An example of a water jacketed extruder die coupled to a Clextral B21 extruder is shown in Figure 2.

An example of such a system is a water jacket, optionally but preferably provided with a water distribution manifold. Water of a given temperature may enter the jacket and flow either with, or counter to, the flow of the material being extruded, such that the water exits the jacket at a higher temperature, having absorbed heat from the cooling die and thus the material being extruded. Preferably any cooling fluid used in a jacketed arrangement flows counter to the flow of the material being extruded. It is believed that this provides the most gradual cooling effect and enhances the sensorial experience.

In some embodiments, a cooling system is implemented such that material being extruded enters the extruder die at a temperature of about 150 °C and exits the extruder die at a temperature of about 40 °C. This cooling can be achieved by the flow of cool water (about 14 °C) through a water jacket and moving counter to the flow of the material being extruded along the channel. The cool water absorbs heat from the extruder die and may exit the water jacket as steam/boiling water (about 100 °C). It has been found that for a throughput of material to be extruded (total, including water) of about 16 kg/hour in the Clextral D32 twin screw extruder that the optimal rate of water flow through a cooling water jacket is about 75 mL/min when the temperature of the water being introduced is 15 °C. The flow rate can be controlled by the use of a needle valve and flow meter. When the Clextral B21 twin screw extruder is used, the throughput of material to be extruded is:

• preferably about 2.8-3.4 kg/hour (such as 3.0-3.2 kg/hour) for the non-water ingredients; and

• preferably about 2.6-3.6 kg/hour (such as 3.6 kg/hour) for the water fed into the extruder to combine with the non-water ingredients. It is believed that water content at these levels improves fibre structure in the extruded product.

The screw speed of the Clextral B21 extruder may be set at about 400 rpm, although the screw speed may vary depending on the extruder being used, for example.

In some embodiments, the extrudate may exit the extruder through a conventionally formed extruder die and portioned using conventional cutting techniques. In such embodiments the extrudate is allowed to cool to ambient temperature such as through exposure to the ambient temperature.

However, the inventors have discovered that preferably the extruder die is configured such that cooling is accelerated by the use of a fluid-filled jacket (such as a water jacket) that cools the material being extruded. Without wishing to be bound by theory it is believed that cooling the material being extruded allows for the production of a solid matrix with minimal or no expansion occurring on exit from the extruder die.

Still more impressively, the inventors have discovered that preferably the extruder die is configured such that cooling is accelerated by the use of a water jacket that cools the material being extruded over only part of the extruder die. More preferably, the extruder die is configured such that cooling is accelerated by the use of a water jacket that cools the material being extruded over only part of the portion of the longitudinal flow path in which the height and width of the cross sectional profile tapers. The partial cooling of the extruder die can be enabled by the use of a prefabricated water jacket of predetermined dimensions or even the use of a dam of variable position within the water jacket so that the user can modulate the regions of accelerated cooling during extrusion. It has been found that retaining heat in the extruder die in the first part of the portion of the longitudinal flow path having the tapering cross sectional profile helps to maintain a reduced viscosity of the material being extruded, and hence maintain a desirable flow rate. In some embodiments, the extruder die is only subject to accelerated cooling in the 50% (such as 40%, such as 30%, such as 25%) of the extruder die closest to the exit aperture. For example, for an extruder die having a length of 1400 mm only the last 300-400 mm is cooled.

The process of extrusion is influenced by a large range of variables. In efforts to enhance the sensorial experience by creating a more realistic texture on the outside of the product, and hance give a better mouthfeel when consuming, significant research was conducted. This research included varying in the ingredient formulations, barrel temperatures, feed rates of dry mix and water, and extruder screw speeds. After prolonged research, the present inventors were surprised to discover a correlation between extrusion back pressure and cooling die temperature. Without wishing to be bound by theory the inventors believe that optimal surface texture (and hence sensorial experience) can be achieved by cooling the extruder die so as to provide back pressure on the mixture being extruded, and hence the motor(s) driving the extruder screws. It was found that when using the Clextral D32 twin screw extruder an optimal range of from 45-80 bar back pressure, and more preferably from 50 to 65 bar back pressure produced a significantly roughened surface to the extrudate unseen in previous trials. Independently, but more preferably in combination with this back pressure, using a cooling extruder die wherein water enters at from 2-22 °C so that the water exits at 60-100 °C provides optimal surface texture. This roughened exterior creates a superior eating experience with the two key sensory benefits, superior mouthfeel and higher uptake of flavour in the marinade. The inventors believe that this phenomenon can be replicated in other extruder apparatus by desiring the functional characteristic of cooling the extruder die (and hence extrudate) at a rate that a moderate back pressure is generated so that a roughened surface is generated upon expulsion of the extrudate from the extruder die. Various methods exist for monitoring back pressure in extruders, including the use of a pressure gauge mounted on the extruder, although desiring such moderate back pressure is not routine, and providing the back pressure by intentionally increasing the cooling rate provided by the cooling die is, in the inventors' knowledge, unknown.

Cutting

It will be understood that there are numerous methods for portioning the extrudate into desirable product sizes, including the use of cutting members (such as a rotating blade) that portion the extrudate at an angle (such as at about 90 °C) to the longitudinal flow path, and also the use of cutting members (such as blades, wires) that portion the extrudate substantially parallel to the longitudinal flow path. Preferably the cooling die is configured to portion the extrudate into portions of a desirable dimension, such as the cooling die including at least one cutting member for portioning the extrudate substantially parallel to the longitudinal flow path. For example, the cooling die may include at least one wire mounted close to or at the exit aperture to portion the extrudate substantially parallel to the longitudinal flow path.

Extrusion Process

By way of example only, the ingredients may include solids and liquids. The solids may be mixed (such as in a food grade mixer) and liquid (such as oil) added to the solid, or vice versa. The mixture undergoes subsequent mixing for a time and under conditions such that the mixture is substantially homogenous, such as applying shear such as with a stirring plastic paddle for a period of time, such as 20 minutes. The mixture is then placed in the extruder. Water (or additional water) may be added directly into the barrel of the extruder after the mixture has been added. The water may comprise between 45 and 65% (w/w) of the total weight of the extruded product; such as between 50% (w/w) and 60% (w/w); such as approximately 50% (w/w); such as approximately 56% (w/w).

Form of Product

The extrudate of the present invention may be used as a HMMA in a number of applications including to provide a substitute for well known portioned meat products which may vary by geographical region and/or mode of preparation and include jerky, biltong, pork chip, meat sticks and bars, toppers (such as bacon bits), bakkwa, coppiette, uppu kandam, qwant'a, kilishi, ch'arki (charque, charqui). The product may also be used as a dried meat substitute in general cooking when prepared as chunks. In general, the extrudate of the invention may be used in any application where dried meat can be used. However, by virtue of the plant-based nature of the product, it is believed that the extrudate of the invention is capable of significant shelf life, and avoidance of turning rancid.

Post-extrusion processes

The product of extrusion is edible and provides a suitable sensorial experience and accordingly meets at least one object of the invention.

Nonetheless, a range of post-extrusion processes may be implemented to further enhance the sensorial experience of the consumer.

Marination

While flavourful ingredients can be incorporated in the non-water ingredients added to the extruder, it has been found that such flavourful ingredients do not tend to survive the extrusion process with significant intact flavour. As such, it is preferable that any flavourful ingredients are added in a postextrusion process - one such process being marination. Marination may impart enhanced flavour upon the HMMA. Marination flavour is largely predicated on consumer preference, and style of product. In the case of a HMMA jerky product, commercially available beef jerky flavours include: teriyaki; sweet and hot; and original.

Conditions that may be varied to achieve the stated function include modulating the temperature (typically between 0 °C and 85 °C, such as between 0 °C and 75 °C, 0 °C and 50 °C, such as between 0 °C and 30 °C, such as around 4 °C or around 20-25 °C), and pressure (including atmospheric pressure, elevated pressure, and reduced pressure (such as partial vacuum)).

The time for which the contacting step occurs may range from several seconds to several days, although typically the contacting step will occur for a matter of hours, such as 1-24 hours.

The process may involve contacting the extrudate with a liquid marinade under conditions and for a period of time such that at least a portion of the liquid marinade is incorporated into the HMMA. For example, the extrudate may be soaked in a liquid marinate and stored chilled for at least 1 hour, such as at least 2 hours, preferably at least 4 hours, more preferably at least 6 hours, such as overnight (at least 15 hours). By way of another example, the extrudate may be marinated at ambient temperature for a period of time such as at least 1 hour, such as at least 2 hours, preferably at least 4 hours, more preferably at least 6 hours, such as overnight. An example of the marination vessel is shown in Figure 1. The extrudate may be soaked in a liquid marinate and stored at 70 °C for at least 1 hour, such as at least 2 hours.

The ratio (based on weight) of the HMMA to marinade may be of the order of between 10:1 and 1:10, such as between 5:1 and 1:5, such as between 3:1 and 1:3; such as between 1:1 and 1:2, such as about 1:1.5.

Examples of flavourful ingredients that can be used include: sweeteners (golden syrup, and molasses); spice extracts (garlic, onion, black pepper, capsicum, chilli, and ginger extracts); and yeast extracts.

Drying

Before or after any marination step (preferably after the use of a marination step), the HMMA may undergo a drying process. The drying process may take place at an elevated temperature (above ambient) such as above 35 °C, such as above 40 °C, such as above about 45 °C. Preferably the drying process takes place at a temperature of no more than 60 °C, such as no more than 55 °C. Ideally the drying takes place between 45 °C and 55 °C.

Such a drying process may lead to the loss of up to 40% (or even more) of the weight of the HMMA product.

In some embodiments, the protein content of the wet extrudate may be 32.8% (w/w) and upon drying the protein content may reach about 50% (w/w), such as about 45% (w/w).

Drying may be achieved by placing portioned product on a wire rack and providing a flow of air around the product so that moisture is lost to the air. The air may be circulated with, for example, a fan to increase the rate of drying.

The product may be dried for sufficient time (such as at least 2 hours, such as at least 4 hours, such as at least 7 hours) to achieve the desired moisture content. The HMMA may be dried for 4-9 hours depending on the product/thickness, temperature.

Examples Formulation Studies Table

+++ optimal, ++ good, + acceptable, - less preferable Davis Pea T-full Pea Elmsland Pea

Nutralys Pea 2.6 kg/h feed rate 3.2 kg/h feed rate

a = 2.8 kg/hr feed rate; b = 3.0 kg/hr feed rate; c = 3.2 kg/hr feed rate

Golden Syrup 0 Molasses

1 Apple Juice Concentrate

31

Extruder Die

In some embodiments, the peculiar design characteristics of the cooling die of the present invention described herein may be provided by an extruder die formed from a plurality of parts. For example, the extruder die may be formed from two parts that may be fastened together to create the longitudinal flow path described herein. In some embodiments the extruder die may include two substantially half parts, each of which seal together to contain the longitudinal flow path. One such embodiment is shown in Figure 4. Also shown in Figure 4 are two optional plates that may be secured between the two substantially half parts to modulate the shape of the longitudinal flow path. The plurality of parts may be secured together using conventional means such as bolts.

It will be understood that the extruder die of the invention is typically subject to substantial pressure and/or temperature. In some embodiments the extruder die is configured to allow the passage of a fluid internally so as to cool the mixture as it moves along the longitudinal flow path. The extruder die may be manufactured from a range of materials, and may be made by additive and substractive manufacturing techniques. In some embodiments, the extruder die may be formed by milling from a piece or pieces of metal. For example, the extruder die may be manufactured by milling one or more pieces of aluminium, or a similar machinable resilient material that is optionally capable of conducting heat.

In some embodiments, a sealing member (such as a rubber seal) may be placed between parts used to form the extruder die, although preferably parts used to form the extruder die are manufactured with sufficiently tight tolerances that they form a usable seal themselves without the need for any sealing member.

Nominally, and purely for distinction purposes, the two substantial halves may be referred to as the bottom half (2) and the top half (4), although this nomenclature is arbitrary and the orientation may be varied as desired without altering the shape of the longitudinal flow path. One or both of the parts of the extruder die may be provided with a port (6) or ports for ingress or egress of a fluid to modulate temperature of the extruder die.

The extruder die in this case may optionally be provided with one or more plates (8) to further modulate the longitudinal flow path, although said plate(s) is generally absent. Figure 5 shows an isometric view of the internal view of the bottom part (2) of the exemplary extruder die shown in Figure 4. As used herein, the term "internal" in the context of "internal view" is intended to refer to that part of the bottom part that is substantially hidden from view when the extruder die is in use. As shown, the bottom part provides a part of the elongate internal channel (10) of the invention that lies between the part of the entrance aperture (12) formed by the bottom part (2) and the exit aperture (14) formed by the bottom part (2).

Figure 6 shows an isometric view of the external view of the bottom part (2) of the exemplary extruder die shown in Figure 4. As used herein, the term "external" in the context of "external view" is intended to refer to that part of the bottom part that is substantially visible when the extruder die is in use. In this embodiment the bottom part is provided with a three dimensional profile that includes a series of parallel ridges (16). The provision of this three dimensional profile is believed to provide a heat sink so as to increase the rate of heat loss from the material moving along the longitudinal flow path to the extruder die and subsequently to the external environment.

Figure 7 shows an end view of the entrance aperture end of the bottom part (2) of the exemplary extruder die shown in Figure 4. In this embodiment, the part (12) of the entrance aperture provided by the bottom part has a substantially rectangular cross sectional profile.

Figure 8 shows an end view of the exit aperture end of the bottom part (2) of the exemplary extruder die shown in Figure 4. In this embodiment, the part (12) of the entrance aperture provided by the bottom part has a substantially rectangular cross sectional profile. The part (14) of the exit aperture provided by the bottom part has a substantially rectangular cross sectional profile. As shown, the width of the part of the elongate internal channel (10) changes from a first width provided by the part (12) of the entrance aperture provided by the bottom part to a second width provided by the part (14) of the exit aperture provided by the bottom part.

Figure 9 shows a plan view of the internal view of the bottom part (2) of the exemplary extruder die shown in Figure 4, more clearly showing that the width of the part of the elongate internal channel (10) tapers from a first width provided by the part (12) of the entrance aperture provided by the bottom part to a second width provided at a position (17) that is at a distance along the elongate internal channel (10) from the part (12) of the entrance aperture provided by the bottom part. In this embodiment the change in width occurs over part of the elongate internal channel. In this embodiment, tapering region (18) may be followed by a region (20) of substantially uniform width - as described herein this region (20) is an example of a non-tapering region.

Figure 10 shows a plan view of the external view of the bottom part (2) of the exemplary extruder die shown in Figure 4, more clearly showing a series of parallel ridges (16) that may be formed by milling material (between the ridges) from the bottom part.

Figure 11 shows a side view of the bottom part of the exemplary extruder die shown in Figure 4, further showing the inclusion of two ports (6) for ingress or egress of a fluid to modulate temperature of the extruder die.

Figure 12 shows an isometric view of the internal view of the top part (4) of the exemplary extruder die shown in Figure 4. As shown, the top part provides a part of the elongate internal channel (22) of the invention that lies between the part of the entrance aperture (24) formed by the bottom part (4) and the exit aperture (26) formed by the bottom part (4).

Figure 13 shows an isometric view of the external view of the top part (4) of the exemplary extruder die shown in Figure 4. In this embodiment the top part is provided with a three dimensional profile that includes a series of parallel ridges (28). The provision of this three dimensional profile is believed to provide a heat sink so as to increase the rate of heat loss from the material moving along the longitudinal flow path to the extruder die and subsequently to the external environment.

Figure 14 shows an end view of the entrance aperture end of the top part (4) of the exemplary extruder die shown in Figure 4. In this embodiment, the part (24) of the entrance aperture provided by the top part is equal in height to the remainder (28) of the aperture end of the top part (4). The distant exit aperture end of the top part (26) stands proud at a height above the remainder (30) of the exit aperture end of the top part (2).

Figure 15 shows an end view of the exit aperture end (26) of the top part (4) of the exemplary extruder die shown in Figure 4

Figure 16 shows a plan view of the internal view of the top part (4) of the exemplary extruder die shown in Figure 4, more clearly showing that the width of the part of the elongate internal channel (22) tapers from a first width provided by the part (24) of the entrance aperture provided by the top part to a second width provided at a position (31) that is at a distance along the elongate internal channel (22) from the part (24) of the entrance aperture provided by the top part. In this embodiment the change in width occurs over part of the elongate internal channel. In this embodiment, tapering region (32) may be followed by a region (34) of substantially uniform width - as described herein this region (34) is an example of a non-tapering region.

Figure 17 shows a plan view of the external view of the top part (4) of the exemplary extruder die shown in Figure 4, more clearly showing a series of parallel ridges (28) that may be formed by milling material (between the ridges) from the top part.

Figure 18 shows a side view of the top part of the exemplary extruder die shown in Figure 4, further showing the inclusion of two ports (36) for ingress or egress of a fluid to modulate temperature of the extruder die. Additionally, Figure 18 shows that the part of the elongate internal channel of the invention that lies between the part of the entrance aperture (24) formed by the bottom part (4) and the exit aperture (26) formed by the bottom part (4) has a height that changes from the entrance aperture (the first height as described herein) to a position (37) that is at a distance along the elongate internal channel from the part (24) of the entrance aperture. The height at the position (37) is the second height as described herein. Region (38) is provided with a tapering height and region (40) is provided with a substantially uniform height - as described herein this region (40) is an example of a non-tapering region.

Securing together the bottom part (2) and the top part (4) forms an extruder die (42; Figure 19) for incorporation in an extruder, the extruder die having an elongate internal channel, wherein the elongate internal channel (formed from (10) and (22)) includes: i) an entrance aperture (formed from (12) and (24)) for receiving material mixed in the extruder; ii) an exit aperture (formed from (14) and (26)) through which extrudate exits the extruder; and iii) a longitudinal flow path between the entrance aperture and the exit aperture such that the material mixed in the extruder moves under pressure along the longitudinal flow path in use, wherein the elongate internal channel has, along at least a portion of the longitudinal flow path, a cross sectional profile that: i) tapers from a first height to a second height (in region (38) from the height at the part of the entrance aperture (24) formed by the bottom part (4) to the height at position (37)); and ii) tapers from a first width to a second width (in region (18) from the width at the part of the entrance aperture (12) provided by the top part to a second width provided at a position (17); and/or in region (32) from the width at the part of the entrance aperture (24) provided by the top part to a second width provided at a position (31)), such that the area of the cross sectional profile in the at least portion differs by no more than 50%.

As the extrudate (43; Figure 19) exits the extruder it may be portioned as desired using cutting members such as wires inserted in the extruder die through the exit aperture (46) (formed from (14) and (26)). Further portioning may take place to generate extrudate (48) (Figure 20) of the desired dimension.

A second exemplary embodiment of the cooling die of the invention is shown in part(s) in Figure 22 to Figure 30.

Figure 22 shows an isometric view of the internal view of the bottom part (50) of a second exemplary extruder die. As used herein, the term "internal" in the context of "internal view" is intended to refer to that part of the bottom part that is substantially hidden from view when the extruder die is in use. As shown, the bottom part provides a part of the elongate internal channel (52) of the invention that lies between the part of the entrance aperture (54) formed by the bottom part (50) and the exit aperture (56) formed by the bottom part (50).

Figure 23 shows an end view of the entrance aperture end of the bottom part (50) of a second exemplary extruder die. In this embodiment, the part (54) of the entrance aperture provided by the bottom part has a substantially rectangular cross sectional profile.

Figure 24 shows an end view of the exit aperture end of the bottom part (50) of a second exemplary extruder die. In this embodiment, the part (54) of the entrance aperture provided by the bottom part has a substantially rectangular cross sectional profile. The part (56) of the exit aperture provided by the bottom part has a substantially rectangular cross sectional profile. As shown, the width of the part of the elongate internal channel (52) changes from a first width provided by the part (54) of the entrance aperture provided by the bottom part to a second width provided by the part (56) of the exit aperture provided by the bottom part.

Figure 25 shows a plan view of the internal view of the bottom part (50) of a second exemplary extruder die, more clearly showing that the width of the part of the elongate internal channel (52) tapers from a first width provided by the part (54) of the entrance aperture provided by the bottom part to a second width provided at a position (58) that is at a distance along the elongate internal channel (52) from the part (54) of the entrance aperture provided by the bottom part. In this embodiment the change in width occurs over part of the elongate internal channel. In this embodiment, tapering region (60) may be followed by a region (62) of substantially uniform width - as described herein this region (20) is an example of a non-tapering region.

Figure 26 shows a plan view of the external view of the bottom part (50) of a second exemplary extruder die, more clearly showing a series of sunken/cut out/milled regions (64) that may be formed by milling material from the bottom part. Figure 26 also shows a series of cooling zones Zl, Z2, Z3, Z4 through which a coolant such as water may be passed in the respective directions shown with arrows.

Figure 27 shows an isometric view of the internal view of the top part (66) of a second exemplary extruder die. As shown, the top part provides a part of the elongate internal channel (68) of the invention that lies between the part of the entrance aperture (70) formed by the bottom part (66) and the exit aperture (72) formed by the bottom part (66).

Figure 30 shows a plan view of the internal view of the top part (66) of a second exemplary extruder die, more clearly showing that the width of the part of the elongate internal channel (68) tapers from a first width provided by the part (70) of the entrance aperture provided by the top part to a second width provided at a position (74) that is at a distance along the elongate internal channel (68) from the part (70) of the entrance aperture provided by the top part. In this embodiment the change in width occurs over part of the elongate internal channel. In this embodiment, tapering region (76) may be followed by a region (78) of substantially uniform width - as described herein this region (78) is an example of a nontapering region.

Securing together the bottom part (50) and the top part (66) forms an extruder die that shares some similarities with the extruder die shown in Figure 19 as 42. Extrudate, extruded from any extruder die of the present invention, may optionally undergo one or more conditioning step(s). The conditioning step(s) may, for example, include mechanical processing.

Figure 31 shows a photograph of a device (80) that may be positioned at the exit of an extruder die so that extrudate is fed between two textured rollers (one shown as 82), in this case bearing wire bristles (the bristles being preferably of the order of 0.2 mm in diameter). As shown, one or more of the textured rollers may be configured to rotate in the same direction tangentially at the point of contact as the extrudate is moving. In some embodiments the textured rollers may be configured to rotate in the opposite direction tangentially at the point of contact as the extrudate is moving. Rotation of the rollers may be achieved through any suitable means and in this case is achieved through the use of an electric motor (84). Without wishing to be bound by theory, the implementation of a conditioning step performed after the extrudate leaves the extruder die is believed to assist with the ability of the extrudate to absorb liquid marinade, the ability for it to dry, and its overall texture including mouthfeel.

Figure 32 shows a photograph of the second exemplary extruder die (86) of the invention configured with an entrance aperture (88; hidden) for receiving material mixed in the extruder (90; partially shown) and an exit aperture (92) through which extrudate exits the extruder.

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to".

The entire disclosures of all applications, patents and publications cited above and below, if any, are herein incorporated by reference.

Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world.

The invention may also be said broadly to consist in the parts, elements, characteristics and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements, characteristics or features. Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined herein. Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present invention.

Claims

Claims:

1. A high moisture meat analogue (HMMA) product produced by extrusion of water and a mixture including:

(i) plant-based protein including pea protein and/or faba bean protein;

(ii) sugar;

(iii) lipid; and

(iv) starch.

2. The HMMA product according to claim 1 wherein the plant-based protein is included at 15-95% w/w of the mixture.

3. The HMMA product according to claim 1 or claim 2 wherein the plant-based protein is included at 80-92% w/w of the mixture.

4. The HMMA product according to any one of claims 1 to 3 wherein the plant-based protein consists of pea protein and faba bean protein.

5. The HMMA product according to any one of claims 1 to 4 wherein the sugar is a monosaccharide.

6. The HMMA product according to any one of claims 1 to 5 wherein the sugar is included at less than 20% w/w of the mixture.

7. The HMMA product according to any one of claims 1 to 6 wherein the lipid is included at 1-10% w/w of the mixture.

8. The HMMA product according to any one of claims 1 to 6 wherein the starch is included at 1- 10% w/w of the mixture.

9. The HMMA product produced according to any one of claims 1 to 8 wherein the HMMA product contains less than 5% w/w of soy protein.

10. The HMMA product produced according to any one of claims 1 to 8 wherein the HMMA product contains substantially no soy protein.

11. The HMMA product produced according to any one of claims 1 to 10 wherein water is present at between 45 and 65% (w/w) of the total weight of the extruded product.

12. The HMMA product produced according to any one of claims 1 to 11 wherein at least 20% of the fibres of the HMMA product are substantially aligned.

13. The HMMA product produced according to any one of claims 1 to 12 wherein the HMMA product is capable of absorbing at least 6% of the weight of the HMMA product of a liquid in which it is soaked for 2 hours at 70 °C.

14. A mixture for use in the formation of a high moisture meat analogue (HMMA) product, the mixture including:

(i) plant-based protein including pea protein and/or faba bean protein;

(ii) sugar;

(iii) lipid; and

(iv) starch.

15. The HMMA product according to claim 14 wherein the plant-based protein is included at 15-95% w/w of the mixture.

16. The mixture according to claim 14 or claim 15 wherein the plant-based protein is included at 80- 92% w/w of the mixture.

17. The mixture according to any one of claims 14 to 16 wherein the plant-based protein consists of pea protein and faba bean protein.

18. The mixture according to any one of claims 14 to 17 wherein the sugar is a monosaccharide.

19. The mixture according to any one of claims 14 to 18 wherein the sugar is included at less than 20% w/w of the mixture.

20. The mixture according to any one of claims 14 to 19 wherein the lipid is included at 1-10% w/w of the mixture.

21. The mixture according to any one of claims 14 to 20 wherein the starch is included at 1-10% w/w of the mixture.

22. An extrusion process for making a high moisture meat analogue (HMMA) product, the process including the step of: a) introducing into an extruder a mixture according to any one of claims 14 to 21; b) combining the mixture with water; c) extruding the combined mixture and water through an extruder die.

23. The extrusion process according to claim 22 wherein the material being extruded enters the extruder die at a temperature of about 150 °C and exits the extruder die at a temperature of about 40 °C.

24. The extrusion process according to claim 22 or claim 23 wherein the extruder die is only subject to accelerated cooling in the 50% of the extruder die closest to the exit aperture.

25. The extrusion process according to any one of claims 22 to 24 including the further step of subjecting the HMMA product to a drying step following extrusion to remove at least some of the water so that the protein content is about 45% w/w.

26. An extruder die for incorporation in an extruder, the extruder die having an elongate internal channel, wherein the elongate internal channel includes: i) an entrance aperture for receiving material mixed in the extruder; ii) an exit aperture through which extrudate exits the extruder; and iii) a longitudinal flow path between the entrance aperture and the exit aperture such that the material mixed in the extruder moves under pressure along the longitudinal flow path in use, wherein the elongate internal channel has, along at least a portion of the longitudinal flow path, a cross sectional profile that: i) tapers from a first height to a second height; and ii) reverse-tapers from a first width to a second width, such that the area of the cross sectional profile in the at least portion of the longitudinal flow path differs by no more than 50%.

27. The extruder die according to claim 26 wherein the area of the cross sectional profile in the at least portion of the longitudinal flow path differs by no more than 25%.

28. The extruder die according to claim 26 wherein the area of the cross sectional profile in the at least portion of the longitudinal flow path differs by no more than 5%.

29. The extruder die according to any one of claims 26 to 28 wherein the elongate internal channel tapers from a height of about 10 mm to about 4 mm in at least a portion of the longitudinal flow path.

30. The extruder die according to any one of claims 26 to 29 wherein the elongate internal channel reverse-tapers from a width of about 50 mm to about 120 mm in at least a portion of the longitudinal flow path.

31. The extruder die according to any one of claims 26 to 27 wherein the elongate internal channel tapers from a height of about 10 mm to about 6 mm in at least a portion of the longitudinal flow path.

32. The extruder die according to any one of claims 26 to 27 or claim 31 wherein the elongate internal channel reverse-tapers from a width of about 60 mm to about 150 mm in at least a portion of the longitudinal flow path.

33. An extrusion process for making a high moisture meat analogue (HMMA) product, the process including the step of: a) introducing into an extruder a mixture including:

(i) plant-based protein including pea protein and/or faba bean protein;

(ii) sugar;

(iii) lipid; and

34. The extrusion process according to claim 33 wherein the material being extruded enters the extruder die at a temperature of about 150 °C and exits the extruder die at a temperature of about 40 °C.

35. The extrusion process according to claim 33 or claim 34 wherein the extruder die is only subject to accelerated cooling in the 50% of the extruder die closest to the exit aperture.

36. The extrusion process according to any one of claims 33 to 35 including the further step of subjecting the HMMA product to a drying step following extrusion to remove at least some of the water so that the protein content is about 45% w/w.

37. The extrusion process according to any one of claims 33 to 36 wherein the area of the cross sectional profile in the at least portion of the longitudinal flow path of the extruder die differs by no more than 25%.

38. The extrusion process according to claim 37 wherein the area of the cross sectional profile in the at least portion of the longitudinal flow path of the extruder die differs by no more than 5%.

39. The extrusion process according to any one of claims 33 to 38 wherein the elongate internal channel of the extruder die tapers from a height of about 10 mm to about 4 mm in at least a portion of the longitudinal flow path.

40. The extrusion process according to any one of claims 33 to 39 wherein the elongate internal channel of the extruder die reverse-tapers from a width of about 50 mm to about 120 mm in at least a portion of the longitudinal flow path.

41. The extrusion process according to any one of claims 33 to 38 wherein the elongate internal channel of the extruder die tapers from a height of about 10 mm to about 6 mm in at least a portion of the longitudinal flow path.

42. The extrusion process according to any one of claims 33 to 38 or claim wherein the elongate internal channel of the extruder die reverse-tapers from a width of about 60 mm to about 150 mm in at least a portion of the longitudinal flow path.