GB2563379A

GB2563379A - Foodstuffs

Info

Publication number: GB2563379A
Application number: GB1707876.7A
Authority: GB
Inventors: John Andrew Finnigan Timothy; Adetokunbo Akintoye Muyiwa; James Ellis Evans Alexander; Mousavi Reza
Original assignee: Marlow Foods Ltd
Current assignee: Marlow Foods Ltd
Priority date: 2017-05-16
Filing date: 2017-05-16
Publication date: 2018-12-19
Anticipated expiration: 2037-05-16
Also published as: WO2018211243A1; GB201707876D0; GB2563379B

Abstract

A method of making a foodstuff comprises: (i) selecting a mass of material which comprises a filamentous fungus, has been cryogenically frozen and subsequently defrosted, and is at a temperature of at least 1°C; and (ii) contacting said mass of material with one or more other ingredients which are to be included in the foodstuff. By use of a cryogenically frozen mass comprising filamentous fungus, a homogenous foodstuff can readily be prepared on an industrial scale, even after very long term storage of the mass, by mixing said mass with other ingredients. Also disclosed is a foodstuff comprising (i) a filamentous fungus which has been cryogenically frozen and subsequently defrosted; and (ii) one or more other ingredients mixed with said filamentous fungus.

Description

Foodstuffs

This invention relates to a foodstuff and particularly, although not exclusively, relates to a foodstuff which comprises a filamentous fungus. In a preferred embodiment, the foodstuff is a meat substitute. The invention also extends to a process for making the foodstuff and a foodstuff made in the process.

It is known, for example from WO 00/15045 (DSM), W096/21362 (Zeneca) and W095/23843 (Zeneca) to use edible filamentous fungi as a meat-substitute, for example in the preparation of burgers and sausages. In such uses, filaments of the fungi are bound together, for example with egg albumin, and are texturised so that the product resembles muscle fibres and therefore has a meat-like appearance and texture. Meat substitutes of the type described have been widely commercially available for many years under the trade mark QUORN.

Texturization of products incorporating filamentous fungus involves a carefully controlled process. For example, foodstuffs comprising filamentous fungus are subjected to freeze texturization which aims to affect the fungus so it produces a texture similar to animal muscle meat texture in foodstuffs. To mimic natural meat texture, a foodstuff incorporating filamentous fungus should ideally satisfy two major aspects of natural meat texture - firstly, it should have a fibrous texture on chewing; and, secondly, it should release liquid (i.e. be juicy) on chewing. Freeze texturization is found to advantageously produce the aforementioned aspects of natural meat in foodstuffs incorporating filamentous fungus.

It is desirable to be able to store filamentous fungus prior to incorporation into foodstuffs. This would allow the filamentous fungus to be transported long distances from the place of manufacture to another place where the filamentous fungus may be used to produce a foodstuff; and would allow excess filamentous fungus produces in a fermentation plant to be stored until needed. However, storage of filamentous fungus which subsequently needs to be texturized to produce an edible foodstuff is not trivial. Less than optimum storage can be detrimental to the production and eating quality of a foodstuff incorporating stored material.

Although not publicly disclosed, filamentous fungus may be treated for storage on an industrial scale by use of air blast freezing. In the process, air at a temperature between -18°C and -34°C is passed through a tunnel in which a belt carrying blocks of the filamentous fungus to be frozen are also passed. During such passage, the filamentous fungus becomes frozen and, thereafter, it can be stored at -18°C to -25°C in a commercial/industrial cold storage unit until it is needed in the preparation of a foodstuff. The aforementioned process works well and allows the filamentous fungus to be stored for three to four months before being incorporated into a foodstuff. However, longer term storage can lead to problems downstream. In particular, Applicant has found that, after three to four months storage of filamentous fungus frozen as described, it is difficult to disperse defrosted filamentous fungus into foodstuffs using industrial mixers. As a result, if such defrosted material is used in foodstuffs, there is a risk that foodstuffs produced may not be properly mixed, leading to production of foodstuffs which are not homogenous. Since such foodstuffs are likely to be unacceptable to consumers, Applicant regards the maximum time filamentous fungus can be stored prior to incorporation into foodstuffs to be three to four months.

It should be appreciated that any method used to freeze filamentous fungus must not detrimentally affect downstream processing, for example freeze texturization, of the filamentous fungus with other ingredients to define a foodstuff which has appropriate mouth feel (e.g. a fibrous texture and juiciness on chewing) which is acceptable to consumers.

It is an object of preferred embodiments of the present invention to address the above described problems.

It is an object of preferred embodiments of the present invention to extend the maximum storage time of filamentous fungus whilst maintaining the ability to readily disperse the fungus with other ingredients in making a foodstuff.

According to a first aspect of the invention, there is provided a method of making a foodstuff, the method comprising:

(i) selecting a mass of material, wherein said mass of material comprises a filamentous fungus; wherein said mass of material has been cryogenically frozen and subsequently defrosted; and wherein said mass of material selected is at a temperature of at least 1°C;

(ii) contacting said mass of material which is at a temperature of at least 1°C with one or more other ingredients which are to be included in the foodstuff.

Advantageously, by use of a cryogenically frozen mass comprising filamentous fungus, a homogenous foodstuff can readily be prepared on an industrial scale, even after very long term storage of the mass, by mixing said mass with other ingredients. The foodstuff prepared enjoys wide-scale consumer acceptance.

Said filamentous fungus suitably comprises particles of said filamentous fungus. Said filamentous fungus preferably comprises fungal mycelia and suitably at least 80 wt%, preferably at least 90 wt%, more preferably at least 95 wt% and, especially, at least 99 wt% of the fungal particles in said foodstuff comprise fungal mycelia. Some filamentous fungi may include both fungal mycelia and fruiting bodies. Said filamentous fungus preferably comprise a filamentous fungus of a type which does not produce fruiting bodies. Where, however, a filamentous fungus of a type which produces fruiting bodies is used, the fungal particles in said foodstuff suitably include at least 80 wt%, preferably at least 90 wt%, more preferably at least 95 wt% of fungal mycelia. Preferably, said fungal particles comprise substantially only fungal mycelia - that is, fungal particles in said foodstuff preferably do not include any fruiting bodies.

Preferred fungi for said fungal particles have a cell wall which includes chitin and/or chitosan. Preferred fungi have a cell wall which includes polymeric glucosamine. Preferred fungi have a cell wall which includes β1 -3 and 1-6 glucans.

Said filamentous fungus preferably comprises fungus selected from fungi imperfecti.

Preferably, said filamentous fungus comprises, and preferably consists essentially of, cells of Fusarium species, especially of Fusarium venenatum A3/5 (formerly classified as Fusarium graminearum) (IMI 145425; ATCC PTA-2684 deposited with the American Type Culture Collection, 10801 University Boulevard, Manassas, VA.) as described for example in WO96/21361 (Zeneca) and WO95/23843 (Zeneca).

Preferably, said filamentous fungus is non-viable. Preferably, said filamentous fungus has been treated to lower the level of RNA of the fungus. Thus, the level of RNA in the filamentous fungus used is preferably less than the level in an identical fungus when in a viable state. The level of RNA in the filamentous fungus is preferably less than 2 wt% on a dry matter basis.

Particles of said filamentous fungus in said foodstuff may comprise filaments having lengths of less than 1000 pm, preferably less than 800 pm. Said filaments may have a length greater than 100 pm, preferably greater than 200 pm. Preferably, fewer than 5 wt%, preferably substantially no, fungal particles in said foodstuff have lengths of greater than 5000pm; and preferably fewer than 5 wt%, preferably substantially no, fungal particles have lengths of greater than 2500 pm. Preferably, values for the number average of the lengths of said fungal particles in said foodstuff are also as stated above.

Particles of said filamentous fungus in said foodstuff may comprise filaments having diameters of less than 20 pm, preferably less than 10 pm, more preferably 5 pm or less. Said filaments may have diameters greater than 1 pm, preferably greater than 2 pm. Preferably, values for the number average of said diameters of said particles in said foodstuff are also as stated above.

Particles of said filamentous fungus in said foodstuff may comprise filaments having an aspect ratio (length/diameter) of less than 1000, preferably less than 750, more preferably less than 500, especially of 250 or less. The aspect ratio may be greater than 10, preferably greater than 40, more preferably greater than 70. Preferably, values for the average aspect ratio of said particles (i.e. the average of the lengths of the particles divided by the average of the diameters of the particles) in said foodstuff are also as stated above.

Suitably, at least a part of said mass (preferably substantially the entirety of said mass) has been cryogenically frozen to a temperature of less than -25°C, preferably less than -35°C, more preferably to less than -45°C. Preferably, the minimum temperature to which the mass has been frozen is higher than -100°C, preferably higher than -60°C

Said mass may have been held at a temperature of less than -25°C for less than 48 hours, for example less than 24 hours.

Said mass may have been held at a temperature of less than -30°C for less than 24 hours, suitably for less than 12 hours, preferably for less than 6 hours or less than 3 hours.

Said mass may have been warmed from its minimum temperature it has been cryogenically frozen to at a rate of at least 0.1°C/hour, preferably at least 0.25°C/hour.

Said mass may have been warmed from its minimum temperature it has been cryogenically frozen to at a rate of less than 5°C/hour, preferably less than 2°C/hour.

Suitably, prior to said mass of material being defrosted, said cryogenically frozen mass of material is stored. It is preferably stored in a frozen state, for example at a storage temperature of less than -10°C, preferably less than -15°C, more preferably less than -18°C. Said storage temperature may be greater than -30°C, for example greater than -25°C. Said storage temperature may be in the range -17°C to -22°C.

Said mass of material may be stored, for example at a said storage temperature as described, for a period of at least 3 months, preferably at least 5 months, more preferably at least 9 months. In some cases, said mass of material may be stored, for example at a said storage temperature as described, for at least 1 year or even at least 1½ years or at least 2 years. Advantageously, it is found that the mass of material described can be stored for very long periods, for example at a said storage temperature as described, whilst maintaining important characteristics of the mass of material, for example the ability to readily disperse the mass of material using industrial mixing equipment and consumer acceptability of foodstuffs made using such a mass of material. .Suitably the mass of material is stored for 6 months to 3 years, for example 1 year to 3 years or 1 year to 2½ years, in a frozen state, suitably at a temperature in the range -17°C to -22°C, prior to being defrosted.

After storage, for example at a temperature and for a time period as described, said mass of material may be defrosted. It is suitably defrosted so it attains a temperature of at least 1 °C. It may be defrosted so it attains a temperature of at least 2°C. It may be defrosted so it attains a temperature of less than 20°C, preferably 10°C or less. It is preferably defrosted and maintained at a temperature in the range 2°C to 10°C.

Step (ii) of the method suitably comprises dispersing said mass of material with said one or more other ingredients. Advantageously, it is found that, even after a very long term storage as described, said mass of material can readily be dispersed using industrial mixing equipment. This is in contrast to the dispersibility of a mass of material frozen by an alternative method to that described.

In step (ii) of the method, said mass of material may be at a temperature of at least 2°C, immediately prior to said contact. The temperature may be less than 20°C or 10°C or less.

In step (ii), said mass of material contacted with said one or more other ingredients may include 30 to 95 wt% of filamentous fungus on a wet matter basis. The method may comprise selecting at least 70 wt%, preferably at least 80 wt%, more preferably at least 90 wt% of said mass of material on a wet matter basis and contacting said mass with said other ingredients, up to 100 wt%.

Said one or more other ingredients may include one or more ingredients arranged to deliver calcium ions into said foodstuff.

The foodstuff made in the method suitably includes at least 2,000mg, preferably at least 4,000mg, more preferably at least 6,000mg, especially at least 8,000mg of calcium ions per Kg of filamentous fungus on a dry matter basis. Said foodstuff made in the method suitably includes less than 25,000mg, preferably less than 20,000mg, of said calcium ions per Kg of filamentous fungus on a dry matter basis.

Said foodstuff made in the method may include intracellular calcium ions (e.g. within particles of the filamentous fungus) and extracellular calcium ions. Said foodstuff made in the method suitably includes the following extracellular levels of calcium ions: at least 2,000mg, preferably at least 4,000mg, more preferably at least 6,000mg, especially at least 8,000mg per Kg of filamentous fungus on a dry matter basis. The maximum extracellular level of calcium ions_is suitably less than 25,000mg, preferably less than 20,000mg, per Kg of filamentous fungus on a dry matter basis.

The total amount of calcium ions in said foodstuff is suitably at least 5,000mg per Kg, preferably at least 10,000mg per Kg, of filamentous fungus on a dry matter basis. The total amount of calcium ions may be less than 40,000mg or less than 20,000mg per Kg of filamentous fungus.

Said foodstuff made in the method may include at least 0.100 wt%, preferably at least 0.200 wt%, more preferably at least 0.300 wt%, of calcium ions in total, on a dry weight basis. It may include less than 1 wt% or less than 0.8 wt% of calcium ions in total, on a dry weight basis.

Said one or more ingredients referred to in step (ii) may include an edible hydrocolloid. The total amount of edible hydrocolloid(s) included in said foodstuff may be at least 0.5 wt%, for example at least 1 wt%. The total amount may be less than 10 wt%, preferably less than 5 wt% or less than 3 wt%.

Said one or more ingredients referred to in step (ii) may include egg albumin. For example, said foodstuff prepared may include 0.1 to 5 wt%, for example 0.2 to 4 wt% of egg albumin.

Said one or more ingredients referred to in step (ii) may include one or more flavourants. The total amount of flavourant(s) in said foodstuff may be at least 0.2 wt%, preferably at least 1 wt%. The total amount may be less than 5 wt% or less than 3 wt%.

The total amount of water in said foodstuff prepared in the method may be at least 25 wt%, preferably at least 30 wt%, more preferably at least 50 wt%, especially at least 70 wt%. The total amount of water may be less than 81 wt%. The total amount of water in said foodstuff prepared in the method may be in the range 25 to 81 wt%, preferably in the range 50 to 81 wt%, more preferably in the range 60 to 80 wt%.

Said foodstuff may include:

to 35 wt% (preferably 12 to 30 wt%) of said filamentous fungus on a dry matter basis;

to 85 wt% (preferably 50 to 85 wt%) of water; and to 20% (preferably 3 to 20 wt%) of said one or more other ingredients.

In said foodstuff, a ratio (B) defined as the weight of water divided by the weight of filamentous fungus on a dry matter basis, may be at least 2, preferably at least 3. Ratio (B) may be less than 6, preferably less than 5, more preferably less than 4.5.

After contact as described in step (ii) of the method, and preferably after dispersing of said mass of material, a substantially homogenous material is suitably produced comprising said dispersed mass of material and said one or more other ingredients. Said substantially homogenous mass may be cooked, for example to cause rheological changes, for example setting of egg albumin or other hydrocolloids (when included). Subsequently, said substantially homogenous material may, in a step (iii), be subjected to a reduced temperature of less than 0°C, preferably less than -4°C, more preferably less than -15°. It may be subjected to a temperature in the range -4°C to -25°C, for example in the range -15°C to 25°C. As a result, said substantially homogenous material may be frozen.

In step (iii), said substantially homogenous material is preferably subjected to said reduced temperature for at least 24 hours, preferably at least 96 hours. It may be subjected to said reduced temperature for less than 160 hours. Subsequently, the temperature of said substantially homogenous material may be raised, for example to 0 to 20°C, preferably to 1 to 10°C.

Thereafter, said substantially homogenous material is preferably packaged, suitably in a substantially hermetic package. After packaging, it may be refrigerated (e.g. held at a temperature in the range 0 to 5°C).

Prior to step (i), the method may include a step (i)* which comprises freezing a mass of material as described to define said mass of material which has been cryogenically frozen.

Step (i)* suitably comprises selecting a mass of material which comprises said filamentous fungus, wherein said mass of material is unfrozen and hereinafter referred to as said unfrozen mass. Said selected unfrozen mass is suitably at a temperature of at least 1 °C, for example of at least 2°C, or of at least 3°C. It may be at a temperature of less than 25°C, preferably less than 10°C.

Said unfrozen mass may comprise individual pieces, for example shaped pieces, of said filamentous fungus. At least 90% (preferably substantially 100%) of the number of said pieces have a maximum thickness of less than 5cm, preferably less than 2.5cm, for example less than 1.5cm. The maximum dimension of at least 90% (preferably substantially 100%) of the number of said pieces may be less than 20cm, preferably less than 10cm, more preferably less than 5cm. At least 90% (preferably substantially 100%) of the number of said pieces have a surface area of at least 10cm², preferably at least 20cm²; the surface area may be less than 200cm², preferably less than 100cm².

Preferably, on average, said pieces have a ratio defined as the surface area (in cm²) divided by the weight (in g) of at least 20cm²/g; and said ratio may be less than 250cm²/g. Said ratio may be, on average, in the range 20 to 200cm²/g, preferably 20 to 100cm²/g.

Preferably, on average, said pieces have a ratio defined as the surface area (in cm²) divided by the volume (in cm³) of at least 1 .Ocrri¹, more preferably at least 2.Ocrri¹. Said ratio may be less than 10cm'¹. Said ratio may be, on average, in the range 1.0 to 10cm'¹, preferably in the range 2.0 to 7cm'¹.

In step (i)*, the temperature of said unfrozen mass is preferably reduced by at least 20°C (preferably at least 30°C, more preferably at least 40°C) in less than 4 minutes, for example in less than 3 minutes. Said unfrozen mass is preferably frozen at a rate of at least 0.1 °C per second, for example at a rate of at least 0.2°C per second. The rate may be less than 1°C per second.

In step (i)*, a freezing tunnel is suitably used in which a cryogenic fluid (e.g. carbon dioxide or nitrogen) is caused to flow and contact the unfrozen mass and cause it to freeze. It may be frozen to a temperature of less than -25°C, preferably less than -35°C, more preferably less than -45°C as described above.. The unfrozen mass may be present within the tunnel for less than 10 minutes, for example less than 5 minutes.

After step (i)*, the temperature of said mass of material may be raised to define the material for use in step (i).

According to a second aspect of the invention, there is provided a foodstuff comprising:

(i) a filamentous fungus which has been cryogenically frozen and subsequently defrosted; and (ii) one or more other ingredients mixed with said filamentous fungus.

Said foodstuff is preferably made in a method of the first aspect. Given the different characteristics of the cryogenically frozen filamentous fungus compared to filamentous fungus prepared by other methods, it is believed the foodstuff of the second aspect is novel over known foodstuffs.

Said foodstuff of the second aspect may have any feature of the foodstuff of the first aspect.

Said filamentous fungus suitably comprises particles of said filamentous fungus as describe according to the first aspect. Preferably, said filamentous fungus comprises, and preferably consists essentially of, cells of Fusarium species, especially of Fusarium venenatum A3/5 (formerly classified as Fusarium graminearum) (IMI 145425; ATCC PTA-2684 deposited with the American Type Culture Collection, 10801 University Boulevard, Manassas, VA.) as described for example in WO96/21361 (Zeneca) and WO95/23843 (Zeneca).

Suitably, at least a part of said filamentous fungus (preferably substantially the entirety of said filamentous fungus) has been cryogenically frozen to a temperature of less than -25°C, preferably less than -35°C, more preferably to less than -45°C. Preferably, the minimum temperature to which the filamentous fungus has been frozen is higher than -100°C, preferably higher than -60°C.

Said filamentous fungus is preferably dispersed with said one or more other ingredients. Said one or more other ingredients may include one or more ingredients arranged to deliver calcium ions into said foodstuff.

The foodstuff suitably includes at least 2,000mg, preferably at least 4,000mg, more preferably at least 6,000mg, especially at least 8,000mg of calcium ions per Kg of filamentous fungus on a dry matter. Said foodstuff suitably includes less than 25,000mg, preferably less than 20,000mg, of said calcium ions per Kg of filamentous fungus on a dry matter basis.

Said foodstuff may include intracellular calcium ions (e.g. within particles of the filamentous fungus) and extracellular calcium ions. Said foodstuff suitably includes the following extracellular levels of calcium ions: at least 2,000mg, preferably at least 4,000mg, more preferably at least 6,000mg, especially at least 8,000mg per Kg of filamentous fungus on a dry matter basis. The maximum extracellular level of calcium ions_is suitably less than 25,000mg, preferably less than 20,000mg, per Kg of filamentous fungus on a dry matter basis.

Said foodstuff may include at least 0.100 wt%, preferably at least 0.200 wt%, more preferably at least 0.300 wt%, of calcium ions in total, on a dry weight basis. It may include less than 1 wt% or less than 0.8 wt% of calcium ions in total, on a dry weight basis.

Said one or more ingredients may include an edible hydrocolloid. The total amount of edible hydrocolloid(s) included in said foodstuff may be at least 0.5 wt%, for example at least 1 wt%. The total amount may be less than 10 wt%, preferably less than 5 wt% or less than 3 wt%.

Said one or more ingredients may include egg albumin. For example, said foodstuff prepared may include 0.1 to 5 wt%, for example 0.2 to 4 wt% of egg albumin.

Said one or more ingredients may include one or more flavourants. The total amount of flavourant(s) in said foodstuff may be at least 0.2 wt%, preferably at least 1 wt%. The total amount may be less than 5 wt% or less than 3 wt%.

The total amount of water in said foodstuff may be at least 25 wt%, preferably at least 30 wt%, more preferably at least 50 wt%, especially at least 70 wt%. The total amount of water may be less than 81 wt%. The total amount of water in said foodstuff method may be in the range 25 to 81 wt%, preferably in the range 50 to 81 wt%, more preferably in the range 60 to 80 wt%.

Said foodstuff may include:

Said substantially homogenous material is preferably packaged, suitably in a substantially hermetic package. Said substantially homogenous material is suitably refrigerated (e.g. held at a temperature in the range 0 to 5°C)..

In a third aspect, there is provided a mass of material comprising a filamentous fungus, wherein said mass of material has been cryogenically frozen. The mass of material may be as described in the first and second aspects mutatis mutandis.

Any feature of any aspect of any invention described herein may be combined with any feature of any other aspect of any invention described herein mutatis mutandis.

Specific embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a chart detailing the results of texture analysis on various mycoprotein pastes.

The following material is referred to hereinafter:

Mycoprotein paste -Mycoprotein paste-refers to a visco-elastic material comprising a mass of edible filamentous fungus derived from Fusarium venenatum A3/5 (formerly classified as Fusarium graminearum Schwabe) (IMI 145425; ATCC PTA-2684 deposited with the American type Culture Collection, 12301 Parklawn Drive, Rockville Md. 20852) and treated to reduce its RNA content to less than 2% by weight by heat treatment. Further details on the material are provided in W096/21362 and W095/23843. The material may be obtained from Marlow Foods Limited of Stokesley, U.K. It comprises about 23-25 wt % solids (the balance being water) made up of non-viable RNA reduced fungal hyphae of approximately 400-750pm length, 3-5pm in diameter and a branching frequency of 2-3 tips per hyphal length.

In the following examples, Example 1 describes freezing of mycoprotein paste by a first freezing method which may be compared with a second freezing method, described in Example 2, involving cryogenic freezing, as described in accordance with a preferred embodiment of the invention. Example 3 describes different methods of defrosting the mycoprotein. Example 4 describes an assessment of the dispersibility of defrosted mycoprotein paste. Example 5 describes a backwards extrusion analysis of defrosted paste. Example 6 describes preparing a chicken-style foodstuff. Results of assessments are provided subsequently. The results illustrate the benefits involved in use of the Example 2 process for freezing the paste.

Example 1 - Freezing of mycoprotein paste (First freezing process)

In the process, air blast freezing involves an air blast spiral freezer. In the process, a long, slow moving mesh belt passes through an enclosure containing very cold air in motion. The speed of the belt is variable according to the time necessary to freeze the product which for expediency is in the form of 40g discs of mycoprotein paste. The cold air is introduced into the tunnel at the opposite end from the one where the product to be frozen enters; that is, the air flow is counter to the direction of passage of the product. The temperature of the air used is -21° and the product is within the freezer for about 45 minutes. This is sufficient to freeze the core of the product to a temperature of at least -18°C.

After freezing, the frozen discs are packed into 20kg boxes and moved into a standard commercial cold store held at -18°C to -21 °C.

The above process is currently used commercially but the details described have not been published.

Example 2 - Freezing of mvcoprotein paste (Second freezing process')

A commercially available, liquid-nitrogen-based, cryogenic freezing system was used to cryogenically freeze burger-shaped discs of mycoprotein paste having dimensions of 10mm thickness and 45mm diameter (and a weight of 0.9g after freezing).

The discs were loaded onto a freezer belt and introduced into a freezing tunnel of the system. The tunnel temperature was set at a minimum of -120°C and a minimum retention time of the discs within the tunnel was 2 minutes 30 seconds.

The exit temperature of the discs from the tunnel was about -30°C. After exit, the discs were packed into 20kg boxes and stored at -23°C until used. Data logging showed the temperature of the discs recorded a minimum of about -55°C during the freezing process; and after exiting the tunnel the temperature of the discs stabilised at -23°C after about 16 hours.

Examples 3a to 3c - Defrosting of mvcoprotein paste

As described in Examples 1 and 2 after freezing the paste is stored in a standard commercial cold store and held at -21 °C. Before incorporation into a foodstuff the paste needs to be defrosted. This may be achieved using one of the three processes described below.

(i) Example 3a Process - Defrost in chiller

The frozen paste is placed in a chiller at 4°C to 8°C for at least two nights (ca. 40 hours) to bring the paste to the temperature of the chiller.

(ii) Example 3b Process - Defrost at ambient temperature

The frozen paste is placed in the ambient environment (approximately 20°C for 2-3 hours) to bring the paste up to ambient temperature.

(iii) Example 3c Process - Defrost in steamer

The frozen paste is placed in a kitchen commercial steamer for 3 minutes at 100°C.

Example 4 - General method for assessing defrosted mycoprotein paste dispersibility

To disperse the mycoprotein paste, discs were broken into four equal pieces before being placed in an 800W Kenwood Chef (Trade Mark) mixer and mixed for one minute at speed 1.

Example 5 - Backwards extrusion analysis of defrosted mycoprotein paste

This test measures the consistency of viscous products. A test rig is comprised of a sample container which is centrally located beneath a disc plunger. The disc plunger performs a compression test which extrudes the product up and around the edge of the disc. Samples of paste were assessed. The parameters measured were ‘firmness’, ‘consistency’ and ‘cohesiveness’.

Examples 6a to 6g - General method for preparation of chicken-style foodstuff

Foodstuff was prepared by selecting mycoprotein paste which had been defrosted as described in Examples 3a, 3b or 3c. The paste (93 wt%) was weighed into a mixing bowl of a domestic high speed kitchen mixer and water (1.6 wt%) was added, followed by mixing for 1 to 3 minutes. Then, the other, dry ingredients (flavour (1.83 wt%) and egg albumin (2.2 wt%)) were added and mixed for several minutes. Mixing was intermittently stopped a few times to scrape away any material that was stood away from the impeller of the mixer. Mixing was continued in order to achieve an even distribution of all ingredients within the mix. When an even mix had been produced, mixing was stopped and the mixed materials were placed on grease-proof baking paper and formed into rectangular cross-section blocks of 15mm thickness using a corresponding frame of a forming machine. The blocks were then transferred into a steamer and cooked at 100°C for about 20 minutes to set the egg albumin. After steaming, the blocks were placed in a blast chiller for 15 minutes before being diced manually using a knife into the shape of chicken pieces. The diced pieces were then transferred to a blast freezer on a tray without any packaging, and left to freeze for around 60 minutes. The frozen pieces were then placed inside a marked sample bag and transferred into a cold store where they were held at - 21 °C for at least a week before defrosting for evaluation.

Table 1 summarises the Examples.

Ingredients	Fresh paste	Paste frozen by Example 2 process	Paste frozen by Example 1 process
standard	Defrosting method	Defrosting method
chiller	ambient	steamer	chiller	ambient	steamer
Example 6a	Example 6b	Example 6c	Example 6d	Example 6e	Example 6f	Example 6g
Paste	467.8	467.8	467.8	467.8	467.8	467.8	467.8
Water	8	8	8	8	8	8	8
Egg Albumin	11.1	11.1	11.1	11.1	11.1	11.1	11.1
Calcium chloride	2	2	2	2	2	2	2
Calcium acetate	2	2	2	2	2	2	2
Chicken flavour	9.16	9.16	9.16	9.16	9.16	9.16	9.16
Total	500.00	500.00	500.00	500.00	500.00	500.00	500.00

Table 1

In Table 1, the references to “chiller”, “ambient” and “steamer” correspond to defrosting using the processes of Examples 3a to 3c respectively. The reference to “fresh paste” is to paste which has not been frozen.

Results (i) Dispersibility

Results from the assessment of Example 4 showed that the pastes of Example 2, defrosted as described in any of Examples 3a to 3c were easily dispersed. However, it was found that, from about 5 months onwards, the paste of Example 1 was significantly more difficult to disperse, when defrosted as described in any of Examples 3a to 3c. Given the difficulties in dispersing the paste of Example 1 on a lab scale, it would be expected to be even more difficult to disperse the paste on an industrial scale, since industrial mixers tend not to mix as efficiently as lab scale (kitchen) mixers. It will be appreciated that difficulties with dispersing the paste could lead to leathery (non-dispersed) regions in final products which could be highly detrimental to the quality and acceptability of a consumer product incorporating the paste.

(ii) Texture Analysis

Results of the analysis of Example 5 are provided in Figure 1 which compares firmness, consistency, cohesiveness and viscosity of fresh paste, paste frozen as described in Example 2 and stored for 29 months and paste frozen as described in Example 1. The results shows that the Example 2 paste has characteristics which are, overall, more similar to that of fresh 10 paste (even after 29 months storage) compared to the Example 1 paste.

Thus, the paste of Example 2 is clearly more similar in its rheological properties compared to the Example 1 paste.

(iii) Sensory Analysis

The quality of the paste texture on thawing was subjectively assessed and results are provided in Table 2.

Method of freezing	Defrosting method	Time in storage at -21 °C (months)
0	6	12	18	24
Product quality compared to fresh paste or finished product made from fresh paste
By Example 2 process	Steamer	Normal	Normal	Normal	Firmer	Firmer
Ambient defrost	Normal	Normal	Normal	Firmer	Firmer
Finished product quality (pieces made as per Example 6)	Like standard	Smooth texture	Smooth texture	Smooth texture	Smooth texture
By Example 1 process	Steamer	Normal	Lumpy	Lumpy	Lumpy	Lumpy
Ambient defrost	Tougher than steamed	Lumpy	Lumpy	Lumpy	Lumpy
Finished product quality (pieces made as per Example 6)	Like standard	Bitty texture	Bitty texture	Bitty texture	Bitty texture

Table 2

In general terms, steam defrosted paste was more “watery” than the ambient defrosted paste for paste frozen in both the Example 1 and Example 2 processes. Paste that had been cryogenically frozen as described in Example 2 was, on thawing, very similar to fresh paste. Paste that had been frozen as described in Example 1 and stored for six months had noticeably different textures - the texture was bitty and was generally unacceptable.

(iv) Analysis of chicken-style foodstuff of Examples 6a-6q

A trained panel was used to assess the acceptability of the foodstuff of Examples 6a-6g. It was found that, in each case, for foodstuff made from the paste frozen by Example 2 process, the foodstuff prepared was almost indistinguishable from the equivalent product made from the fresh paste of Example 6a. However, there was evidence of “bittyness” in the foodstuff when made from the past of Example 1, implying it is less acceptable to consumers.

Thus, it should be appreciated that paste frozen as described in Example 2 is advantageous in a number of respects compared to paste frozen by the existing method of Example 1. The Example 2 method can, advantageously, be used to freeze paste for up to about 30 months whilst maintaining consumer acceptability for products made therefrom.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A method of making a foodstuff, the method comprising:

2. A method according to claim 1, wherein said filamentous fungus comprises fungus selected from fungi imperfecti.

3. A method according to claim 1 or claim 2, wherein particles of said filamentous fungus in said foodstuff comprise filaments having lengths of less than 1000 pm; and may have a length of greater than 10 pm.

4. A method according to any preceding claim, wherein at least part of said mass has been cryogenically frozen to a temperature of less than -25°C, preferably to less than -45°C.

5. A method according to any preceding claim, wherein the mass is held at a temperature of less than -25°C for less than 48 hours.

6. A method according to any preceding claim, wherein said mass has been warmed from its minimum temperature it has been cryogenically frozen to at a rate of at least 0,1°C/hour; and may be warmed from its minimum temperature it has been cryogenically frozen to at a rate of less than 5°C/hour.

7. A method according to any preceding claim, wherein, prior to said mass of material being defrosted, said cryogenically frozen mass of material is stored at a storage temperature of less than -10°C, for a period of at least three months, preferably for at least one year.

8. A method according to claim 7, wherein, after storage, said material is defrosted so it attains a temperature of at least 1 °C.

9. A method according to any preceding claim, wherein step (ii) of the method comprises dispersing said mass of material with said one or more other ingredients.

10. A method according to claim 9, which comprises selecting at least 70 wt% (preferably at least 90 wt%) of said mass of material on a wet matter basis and contacting said mass with said other ingredients, up to 100 wt%.

11 A method according to claim 9 or claim 10, wherein said one or more ingredients referred to in step (ii) includes an edible hydrocolloid.

12 A method according to any preceding claims, wherein said foodstuff made in the method includes at least 2000mg (preferably at least 8000mg) of calcium ions per kilogram of filamentous fungus on a dry matter basis.

13. A method according to any preceding claim, wherein the total amount of calcium ions in said foodstuff is at least 5000mg per kilogram of filamentous fungus on a dry matter basis.

14. A method according to any preceding claim, wherein the total amount of water in said foodstuff prepared in the method is at least 25 wt% (preferably at least 70 wt%).

15. A method according to any preceding claim, wherein said foodstuff includes:

10 10 to 35 wt% (preferably 12 to 30 wt%) of said filamentous fungus on a dry matter basis;

40 to 85 wt% (preferably 50 to 85 wt%) of water; and

1 to 20% (preferably 3 to 20 wt%) of one or more other ingredients.

16. A method according to any preceding claim, wherein, in said foodstuff, a ratio (B) defined as the weight of water divided by the weight of filamentous fungus on a dry matter basis is at least 2 and preferably is at least less than 6.

17. A method according to any preceding claim, wherein after contact as described in step (ii) of the method a substantially homogenous material is produced which is subsequently cooked and thereafter in a step (iii) is subjected to a reduced temperature of less than 0°C so that the homogenous material is frozen.

18. A method according to any preceding claim, wherein prior to step (i), the method includes a step (i)* which comprises freezing a mass of material to define said mass of material which has been cryogenically frozen, wherein the unfrozen mass comprises individual pieces of said filamentous fungus, wherein at least 90% of the number of said pieces have a maximum thickness of less than 5cm (preferably less than 1,5cm).

19. A method according to claim 18, wherein on average said pieces have a ratio defined as the surface area (in cm2) divided by the weight (in g) of at least 20cm2/g.

20. A method according to claim 18 or claim 19, wherein, on average, said pieces have a ratio defined as the surface area (in cm2) divided by the volume (in cm3) of at least 1 .Ocrri1.

21. A method according to any of claims 18 to 20 wherein, in step (i)*, the temperature of said unfrozen mass is reduced by at least 20°C in less than four minutes.

22. A method according to any of claims 18 to 21 wherein, after step (i)*, the temperature of said mass of material is raised to define the material for use in step (i).

23. A foodstuff comprising:

24. A foodstuff according to claim 23, wherein at least part of said filamentous fungus has been cryogenically frozen to a temperature of less than -25°C and said foodstuff includes:

15 10 to 35 wt% (preferably 12 to 30 wt%) of said filamentous fungus on a dry matter basis;

40 to 85 wt% (preferably 50 to 85 wt%) of water; and

1 to 20% (preferably 3 to 20 wt%) of said one or more other ingredients.