GB2627739A

GB2627739A - Biomass

Info

Publication number: GB2627739A
Application number: GB2302799.8A
Authority: GB
Inventors: Mercer James; Paul Taylor Mark
Original assignee: Marlow Foods Ltd
Current assignee: Marlow Foods Ltd
Priority date: 2023-02-27
Filing date: 2023-02-27
Publication date: 2024-09-04
Also published as: GB202302799D0; WO2024180311A1

Abstract

A biomass comprising filamentous fungus, wherein said biomass has an L* of at least 70.0. Also disclosed is a method of producing a biomass having increased L* comprising: (i) fermenting cells of a filamentous fungus to produce a biomass; (ii) adjusting the pH of the biomass to increase the L* of the biomass. Further disclosed is the use of an acid and/or increased temperature to increase whiteness and/or increase L* of a biomass produce by fermentation. A product produced by such a method can be a foodstuff. The biomass can have an L* value in the range of 75.0-95.0, a* in the range of -1.0-2.9, b* in the range of 0.5-14.0, and a pH in the range of 2.0-6.0.

Description

Biomass This invention relates to a biomass and particularly, although not exclusively, relates to a biomass comprising a filamentous fungus. Preferred embodiments relate to a biomass which is relatively white in colour.

It is well-known to produce an edible biomass by fermenting Fusarium fungus and harvesting the biomass produced. The harvested biomass may be used in a range of food and non-food applications. For example, biomass may be produced by fermenting Fusarium venenatum and reducing the level of RNA as described in GB2551964A. The biomass may then be mixed with a range of other ingredients to produce a foodstuff for human consumption, for example as described in GB2516491A. Such foodstuffs are well-known and are sold under the brand name QUORN TM.

Disadvantageously, the biomass produced as described in GB2551964A and/or incorporated into QUORN TM branded foodstuffs may be a light tan colour and/or may have an L*, measured as described herein, of less than 70.0 or even lower. In addition, the biomass may have an a* of greater than 3.0 and a b* of greater than 15.0.

It is desirable for some foodstuffs, for example meat-free chicken-replicates or dairy products, such as milks, to be as white as possible, so the foodstuffs mimic equivalent animal products as closely as possible. The colour of the biomass described can hinder achieving that goal.

It is an object of preferred embodiments of the invention to address the above-described 25 problem.

It is an object of preferred embodiments of the invention to provide a biomass having improved whiteness.

It is an object of preferred embodiments of the invention to provide a biomass having an a* of greater than 3.0 and/or a b* of greater than 15.0.

It is an object of preferred embodiments of the invention to provide foodstuffs with improved whiteness and/or aesthetic appeal.

According to a first aspect of the invention, there is provided a biomass comprising filamentous fungus, wherein said biomass preferably has an L* of at least 70.0.

L* of said biomass may be assessed as described hereinafter.

Said biomass may have an L* of at least 75.0, suitably at least 80.0, preferably at least 82.0, more preferably at least 84.0, especially at least 85.0.

The L* of said biomass may be less than 95.0 or less than 91.0.

The biomass may have an a*, assessed as described hereinafter of less than 2.9, suitably less than 2.5, preferably less than 2.0, more preferably less than 1.5. The a* may be at least -1.0.

The biomass may have an b*, assessed as described hereinafter of less than 14.0, suitably less than 10.0, preferably less than 9.0. The b* may be at least 0.5.

Said biomass may have a pH of at least 2.0, preferably at least 3.0, more preferably at least 3.5. The biomass may have a pH of less than 6.0, suitably less than 5.0, preferably less than 4.5, more preferably less than 4.1.

Said biomass may have: L* in the range 75.0 to 95.0, preferably in the range 82.0 to 91.0; and/or a* in the range -1.0 to 2.9, preferably in the range 0 to 2.0; and/or b* in the range 0.5 to 14.0, preferably in the range 0.5 to 10.0; and/or a pH in the range 2.0 to 6.0, preferably in the range 3.5 to 5.0.

Said pH may be measured as described herein, for example using a needle-type pH electrode with built-in temperature compensation.

The term "dry mass basis" (or similar term) refers to the weight of a particular component based on its dry mass -that is, excluding any water or other fluid which may be associated with the component. For example, mycoprotein paste referred to herein may be produced so that it includes about 25 wt% solids (the balance being water) made up of non-viable RNA reduced fungal hyphae. The paste may be said to include 25wt% of fungal hyphae on a dry mass basis and 75wt% water. In this example, the dry mass basis may be determined by heating the mycoprotein paste to remove the water and calculating the water wt% by comparing the weight of the paste before and after water removal.

Said filamentous fungus may include at least 35wt%, preferably at least 40w1%, protein on a dry mass basis. Said filamentous fungus may include less than 65wt%, preferably less than 60wt°/0, protein on a dry mass basis.

Said filamentous fungus may include at least lOwt%, preferably at least 15wt%, dietary fibre on a dry mass basis. Said filamentous fungus may include less than 30wt%, preferably less than 23wt%, dietary fibre on a dry mass basis.

Said filamentous fungus may include at least 4wt%, preferably at least 7wt%, fat on a dry mass basis. Said filamentous fungus may include less than 20wt%, preferably less than lOwt%, fat on a dry mass basis.

Said filamentous fungus suitably comprises filaments having lengths of less than 1000 pm, preferably less than 800pm. Said filaments may have a length greater than 50pm. Preferably, fewer than 5wt%, preferably substantially no, filaments of said filamentous fungus have lengths of greater than 5000pm; and preferably fewer than 5wt%, preferably substantially no filaments have lengths of greater than 2500pm. Preferably, values for the number average of the lengths of said filaments are also as stated above. Thus, the number average of the lengths of said filaments may be in the range 50pm to 1000 pm, preferably in the range 50pm to 500pm.

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

Said filamentous fungus 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 filaments (i.e. the number average of the lengths of the filaments divided by the number average of the diameters of the said filaments are also as stated above. Thus, the number average of the lengths of the filaments divided by the number average of the diameters of the said filaments is preferably in the range 10 to 1000, more preferably in the range 40 to 250.

Preferably, said filamentous fungus 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 said filamentous fungus comprises 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.

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.).

Preferably, said filamentous fungus is non-viable. Preferably, said filamentous fungus has been treated to lower the level of RNA which it contains. Thus, the level of RNA in said filamentous fungus 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 mass basis.

Said biomass may comprise at least 10 wt%, preferably at least 20 wt%, of filamentous fungus on a dry mass basis; and may comprise less than 40 wt%, preferably less than 30 wt%, more preferably less than 26 wt% of filamentous fungus on a dry mass basis.

Said biomass may comprise at least 60 wt%, preferably at least 70 wt%, more preferably at least 74 wt% water; and may comprise less than 90 wt%, preferably less than 80 wt%, of water.

The ratio of wt% of water divided by the wt% of biomass on a dry mass basis may be at least 1, at least 2 or at least 2.8; it may be less than 5 or less than 4.

Said biomass may be the product of a fermentation process as herein described which may be treated as part of the process to adjust its pH and thereby affect the L*, a* and/or b* properties of the biomass as described. The biomass may include residual components from the fermentation medium used in fermentation. The biomass may include an acid counter-ion which was added as part of the process to adjust its pH.

On a dry mass basis, the biomass may include at least 90 wt%, preferably at least 95 wt%, more preferably at least 99 wt%, of filamentous fungus, suitably produced in the fermentation process as described. That is, ignoring any water associated with the biomass, the biomass may include at least 90 wt%, preferably at least 95 wt%, more preferably at least 99 wt%, of filamentous fungus, suitably produced in the fermentation process as described. Thus, the biomass preferably includes a minor amount (if any) solid additives incorporated into the biomass after the fermentation process. Said biomass preferably includes less than 5 wt%, less than 3 wt% or less than 1 wt%, of solid additives incorporated into the biomass after the fermentation process.

Advantageously, using the method of the first aspect results in increased whiteness and/or L* of the biomass and it is found that these improvements are maintained after post-treatment of the biomass and/or incorporation into a product, such as a foodstuff of a non-food as hereinafter described. Thus, the treatment described and/or timing of the treatment suitably produces a long-lasting benefit.

According to a second aspect of the invention, there is provided a method of producing a biomass suitably having increased whiteness and/or L*, the method comprising: (i) fermenting cells of a filamentous fungus to produce a biomass comprising said filamentous fungus; and (ii) adjusting the pH of the biomass, suitably to increase the whiteness and/or L* of the biomass.

The biomass produced may have any feature of the biomass of the first aspect. The method may be a method of producing a biomass having: L* in the range 75.0 to 95.0, preferably in the range 82.0 to 91.0; and/or a* in the range -1.0 to 2.9, preferably in the range 0 to 2.0; and/or b* in the range 0.5 to 14.0, preferably in the range 0.5 to 10.0; and/or a pH in the range 2.0 to 6.0, preferably in the range 3.5 to 5.0.

In step (i), filamentous fungus may be fermented in a receptacle in the presence of a fermentation medium. The pH of the fermentation may, at a first time, be at least 5.5 or at least 6. The pH of the fermentation medium may be monitored, for example substantially continuously, and pH adjusted, for example by addition of an alkali such as ammonium hydroxide.

In step (i), fermentation may be undertaken at a first temperature of less than 35°C, for example in the range 20-30°C. The fermentation medium may be agitated.

After elapse of a time after said first time, for example after elapse of at least 10 hours or at 20 hours (and preferably after less than 48 hours), the temperature at which fermentation is undertaken may be increased, for example gradually, to a second temperature. The difference between the first and second temperatures may be at least 15°C, preferably at least 20°C.

The difference may be less than 40°C or less than 30°C. Preferably, the second temperature is at least 45°C; it may be less than 60°C or less than 55°C. The second temperature may be held for a time of at least 5 minutes or at least 10 minutes; and suitably less than 2 hours or less than 1 hour.

In step (li), the pH of the biomass and/or fermentation medium is preferably adjusted after step (i) and preferably after said first time. The pH is preferably adjusted at or prior to commencement of increasing said temperature to said second temperature.

The pH may be adjusted by addition of acid, for example to the fermentation medium. Said acid may be a protic acid. Said acid may be, for example, a strong acid such as sulphuric acid or hydrochloric acid or a weak acid. Said acid may be selected from: lactic, acetic, phosphoric, ascorbic, pyruvic, citric, formic, nitric and carbonic acids.

In step (ii), the pH of the biomass and/or fermentation medium is preferably lowered suitably so the difference between the pH before lowering and the pH after lowering is at least 1.0, 2.0 or 2.5 pH units. The difference may be less than 4.0 pH units.

In step (ii), the pH of the biomass and/or fermentation medium after lowering may be less than 5.0, less than 4.5, less than 4. The pH is preferably at least 2.0, at least 2.5 or at least 3.0.

Step (ii) is preferably undertaken after a fermentation culture, present in step (i), has reached mid-exponential phase of growth.

It is preferred that, in step (ii), there is both adjustment of pH as described and increase of the temperature of the fermentation from said first temperature to said second temperature.

Adjustment of pH and at least some increase in temperature from said first temperature preferably occur concurrently.

After step (ii), the method may comprise treating the biomass to reduce the level of water associated with the biomass. The method may comprise pressing water from the biomass; it preferably involves centrifugation.

Said treatment to reduce the level of water may occur after the pH of the biomass has been adjusted and/or after the whiteness of the biomass has increased from a previous level of whiteness and/or after the L* of the biomass has increased from a previous L* value.

Treatment of the biomass as described to increase whiteness and/or L* (e.g., acidification and/or heating of biomass) is preferably undertaken at or downstream of a fermenter in which cells of the filamentous fungus are fermented in step (i). Preferably, a receptacle (e.g., a vessel or conduit) in which said treatment of said biomass to increase whiteness and/or L* is undertaken is part of or is in fluid communication with a receptacle in which cells of the filamentous fungus are fermented in step (i). In a preferred embodiment, fermentation in step (i) is undertaken in a first receptacle and treatment of the biomass as described to increase whiteness and/or L* is undertaken in a second receptacle (e.g., a vessel or conduit) which is in fluid communication with said first receptacle and/or is downstream thereof.

After step (H) and said treatment to reduce the level of water as described, the biomass may comprise less than 85 wt%, preferably less than 80 wt% water; and may include at least 15 wt%, preferably at least 20 wt% of biomass, for example filamentous fungus, on a dry mass basis.

Preferably, treatment of said biomass as described to increase whiteness and/or L* is undertaken prior to any active treatment of the biomass to reduce the level of water.

Step (ii) is preferably undertaken on a biomass which includes greater than 75 wt%, greater than 80 wt%, or greater than 85 wt% water. The level of water may be less than 95 wt%.

According to a third aspect of the invention, there is provides a biomass produced in said method of the second aspect.

According to a fourth aspect of the invention, there is provided the use of an acid and/or an increased temperature to increase whiteness and/or increase L* of a biomass produced by fermentation. Said acid and/or said increased temperature is/are preferably used prior to isolation of the biomass from a fermentation process and/or from apparatus in which fermentation is undertaken and from which biomass is isolated.

According to a fifth aspect of the invention, there is provided a product incorporating a biomass according to the first or third aspects and/or produced as described in the second aspect.

Said product may be a foodstuff of a non-food.

When the product is a foodstuff, it may comprise a dairy product (e.g. milk, yogurt or cheese) or a vegetarian or vegan meat-substitute, for example intended to replicate chicken.

Said foodstuff may include one or more ingredients selected from fillers, flavours, oils, fats, proteins or vegetables. Said foodstuff may include at least 5 wt% of said one or more ingredients. Said foodstuff may include at least 20 wt% water.

According to a sixth aspect of the invention, there is provided a method of making a product of the fifth aspect, the method comprising: (i) selecting a biomass as described in any preceding aspect; and (ii) contacting the biomass with other ingredients to define the product.

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

Specific embodiments of the invention will now be described, by way of example, with reference to the accompanying figures in which: Figure 1 is a schematic representation of a fermentation vessel; Figure 2 is a schematic representation of a manual press; and Figure 3 is a schematic diagram showing the steps involved in producing mycoprotein paste with reduced RNA levels.

The following materials are referred to herein: Fusarium venenatum-refers to the strain 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).

Mycoprotein paste -Mycoprotein paste-refers to a visco-elastic material comprising a mass of edible filamentous fungus derived from Fusarium venenatum A3/5 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. 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.

The following assessments are referred to herein.

Assessment 1 -Colour measurement Paste cakes were measured for colour on a MinoltaTM Chroma Meter using SpectraMagicTM software. In the assessment, a thin homogenous layer of paste was measured using a MinoltaChroma lens which had been suitably blanked against a white background (CR210/CR-310/CR410 plate). The layer thickness may be at least 5mm in the region measured so that light is reflected and not transmitted through the paste. Colour readings were given in the L*a*b* format.

Assessment 2 -Total solids measurement These were either measured on a sartorius moisture analyser, or a paste of know weight was dried at 50°C for 48 hours and reweighed and the solids content determined therefrom.

Assessment 3 -Dry cell weight Dry cell weight was measured for a 5m1 sample. This volume was placed on a filter attached to a vacuum filtration device. Most of the water was removed, and the remaining paste dried to completion. Dried cell "pellets" were then weighed and DCW per L of broth determined.

Assessment 4 -pH assessment In a fermenter, pH may be continuously assessed using an Applikon Applisens in line pH probe calibrated against pH 4 and 7 with temperature compensation built in via a fermenter temperature probe.

Outside a fermenter, on a liquid, pH may be assessed using a Mettler Toledo Fiveeasy pH meter with a LE409 probe. Temperature compensation is built in via an in-line probe, calibrated against pH 4 and 7.

A needle-type pH electrode can be used to pierce and penetrate solid samples.

Example 1 -General procedure for producing whiter mycoprotein paste Referring to Figure 1, a 15L Applikon TM glass vessel 2, having a stirrer 4 and inlet tube 6 was used to carry out fermentations.

Fusarium venenatum strain in glycerol was stored as 4m1 aliquots at -80°C in cryovials prior to use.

The inoculum used in the fermentations was a sterile 200m1 volume of the medium described in Table 1, having a pH of 6 which had been incubated (28°C, 110rpm) for 48 hours. The medium was then inoculated with 4m1 of the frozen, mycelium glycerol stock of F. venenatum.

Medium component Potassium dihydrogen phosphate 20 Ammonium chloride 4.4 Potassium sulphate V 0.3 Magnesium sulphate heptahydrate 0.25 TE solution -liquid solution comprising: 5m1 :: ..

Iron II sulphate 7 hydrate 2.8g/L Zinc chloride 1 g/L Manganese II chloride 4 hydrate 1g/L Copper II chloride 0.2g/L Cobalt II chloride V ^ ...........................0.2g/L Na molybdate 0.2g/L CaCl2 hydrate 2g/L Citric acid 1.5g/L Biotin 1m1 0.3g/L water Table 1: Fermentation medium, used in baffled flasks at pH 6 Batch growth was achieved at 10L working volume in the 15L ApplikonTM glass vessel and controlled via EzControlTM software and live data logged via Applikon Lucullus TM software. The batch growth medium comprised the components in Table 2 plus separate, sterile, additions of glucose sugar (33g/L final concentration), phosphoric acid 85%vv (1.16m1/L final concentration) and iron sulphate heptahydrate (0.05g/L final concentration).

Table 2: Fermentation medium For growth, the medium was pH adjusted to pH 6, after all components were added, with 30% v/v ammonium hydroxide which also served as a nitrogen source. The vessel was equilibrated to 28°C, set at an agitation of 600rpm (with two RushtonTM impellors at 10cm distance) and 10L/min air (lvvm) and when equilibrated, the dissolved oxygen (DO) was set to 100% under these conditions.

Off gas analysis was calibrated against air for both carbon dioxide and oxygen content and measured continuously throughout. A setpoint of 30% DO was mandated as a minimum, against a cascade control of 600-1000rpm and 10-20L/min air.

The broth was whitened in situ as follows: Once the culture had reached mid exponential phase of growth (usually after 24-36 hours, at a DO of 30% or when a dry cell weight of 6-8g/L had been achieved) the broth was processed to make it whiter. Processing involved, first, switching off the pH control (to prevent any further additions of ammonium hydroxide; pH measurement however was maintained) and then setting the culture temperature setpoint to 50°C (a slow ramp to this temperature from 28°C then proceeded).

Media component 91_ Potassium sulphate Magnesium sulphate heptahydrate 0.9 Ca acetate 0.2 PPG 0.5m1 TE solution 0.5 ml Manganese sulphate 40g/L Zinc sulphate Copper sulphate Biotin Conc sulfuric acid 50g/L 5g/L 50mg/L 5m1/L Immediately on readjusting the heating setpoint from 28°C, phosphoric acid (or any acid under study), was added via a 3-way feed inlet, to the culture. Concentrated phosphoric acid was typically used (85%) and approximately 5m1 was added to bring the pH down to 4 (or any relevant pH).

The vessel was then left under these conditions until 50°C was measured (via an in-line temperature probe) and then held at that temperature for a further 5 minutes. The total time from temperature setpoint adjustment to this 5-minute hold could be as long at 45 minutes. This step aims to reduce the level of RNA in the biomass. At temperatures above 45°C, the vessel contents could be seen to whiten significantly.

The now whitened cells were harvested directly from the vessel sampling point into a manual press 10, shown in figure 2. Biomass was separated from supernatant or centrate, via a 30uM mesh nylon filtration bag and the manual press. The white paste cake was then stored at 4°C for further use/analysis.

Specific examples, based on the general procedure of Example 1, are provided below.

Example 2: Broth whitening with mid exponential cultures at 50°C and using phosphoric 20 acid Mid exponential broth (MEB) was processed as described in Example 1. Paste from the cultures compared to a control (where no pH adjustment to 4 was made, but processing in all other respects was identical) resulted in a visibly whiter paste. In measuring colour as described in Assessment 1, the L* value shifted up (Lighter) and a* and b* values shifted down (compared to the control) significantly. These changes were maintained with a post processing shift back to pH6, of the whitened cells.

Table 3 details the results.

Sample L* a* b* Control MEB 68.6 6.91 15.4 pH4 Phosphoric acid MEB 87.26 0.28 1.11 Table 3: Colour change values for MEB paste adjusted to pH 4 with phosphoric acid Example 3: Different acids and their impact on whitening.

To further investigate the impact of acids on "fresh cells", two strong and two weak acids were tested (also inorganic and organic acid variants). Both strong acids made the paste visibly whiter (compared to phosphoric), with a smaller decrease in b* values. The weak acids performed as well as each other.

Sample L* a* b" Control 68.6 6.91 15.4 1 at pH 4 with Phosphoric acid 81.6 0.24 1.46 2 at pH 4 with Sulphuric acid 75.12 1.05 6.87 3 at pH 4 with HCI 77.3 0.54 7.04 4 at pH 4 with Acetic acid 86.98 0.67 0.97 Table 4: Colour change values for MEB paste adjusted to pH 4 with various acids.

Example 4: Whiteness at different pH values between 3 and 6 A pH profile was run which demonstrated that at least a pH of 4 was preferred to produce acceptable whiteness. A value of pH 3 was also acceptable.

Sample L" a b* pH 6 control 68.6 6.91 15.4 pH 5 71.38 2.62 14.61 pH 4 83.48 -0.1 9.51 pH 3 85.32 -0.18 9.99 Table 7: Colour change values for MEB paste adjusted to various pH Example 5 -Modification of commercial process for producing whiter mycoprotein paste A process for producing mycoprotein paste is shown in Figure 3. The process and variations to produce whiter paste are described below.

A fungal culture is grown in a pressure cycle fermenter 210 at 27°C in the presence of a growth medium. The culture broth passes through a conduit 211 from the fermenter 210 to a pre-heat vessel 220. The culture is pre-heated to 55-60°C (and maintained at the temperature for about 3 to 8 minutes) by waste liquid centrate which is produced further downstream in the process 200, as described below. At this stage, the pH of the culture broth may be lowered as described herein to whiten the paste as described herein. The waste liquid centrate is passed through a heat exchanger (not shown) associated with vessel 220; the waste liquid centrate does not contact the culture directly. The pre-heated culture broth then passes along a conduit 221 to an RNA reduction vessel 230. During this passage, steam (at 7barg and 160°) is injected into the culture broth via a steam injection port 222 in the conduit 221. Steam injection raises the temperature of the culture broth to 64-66°C. The culture broth is held at this temperature in the vessel 230 for at least 30 minutes. At this stage, the pH of the culture broth may be lowered as described herein to whiten the paste as described herein. The culture broth then passes from the RNA reduction vessel 230 to centrifuges 240 via a conduit 231.

During this passage, steam (at 7barg and 160°) is injected into the culture broth via a steam injection port 232 in the conduit 231. This injection of steam increases the temperature of the culture broth to 80-90°C for hygienic purposes.

The centrifuges 240 are run at approximately 5000g and are arranged to separate the mycoprotein paste 250 and waste liquid centrate. Downstream of the centrifuges 240, the mycoprotein paste 250 passes through conduit 241 and is isolated. The waste liquid centrate, which has a temperature of 80-90°C, passes through conduit 242 to a heat exchanger associated with the pre-heat vessel 220. Thus, the centrate is used to heat the culture broth in the pre-heat vessel 220.

After heating the pre-heat vessel via the heat exchanger, the waste liquid centrate, which at this stage has a temperature of 40-50°C, passes through conduit 243 to a cooler 260. The centrate, containing waste RNA and waste RNA digestion products, is cooled to 30°C and travels through conduit 261 to an effluent treatment plant (ETP) 270 for disposal.

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

CLAIMS: 1 A biomass comprising filamentous fungus, wherein said biomass has an L* of at least 70.0.
2 A biomass according to claim 1, wherein said biomass has an L* of at least 75.0, suitably at least 80.0, preferably at least 82.0, more preferably at least 84.0, especially at least 85.0.
3 A biomass according to any preceding claim, wherein said L* of said biomass is less than 95.0 or less than 91.0.
4 A biomass according to any preceding claim, wherein said biomass has an a* of less than 2.9 and at least -1.0; and/or a b* of less than 14.0 and at least 0.5.

A biomass according to any preceding claim, wherein said biomass has a pH of at least 2.0, preferably at least 3.0, more preferably at least 3.5; and/or a pH of less than 6.0, suitably less than 5.0, preferably less than 4.
5, more preferably less than 4.1.
6 A biomass according to any preceding claim, wherein said biomass has: L* in the range 75.0 to 95.0, preferably in the range 82.0 to 91.0; and/or a* in the range -1.0 to 2.9, preferably in the range 0 to 2.0; and/or b* in the range 0.5 to 14.0, preferably in the range 0.5 to 10.0; and/or a pH in the range 2.0 to 6.0, preferably in the range 3.5 to 5.0.
7 A biomass according to any preceding claim, wherein said filamentous fungus comprises fungus selected from fungi imperfecti and, optionally, consists essentially of cells of Fusarium species, for example of Fusarium venenatum.
8 A biomass according to any preceding claim, wherein said filamentous fungus is non-viable and/or the level of RNA in the filamentous fungus is less than 2 wt% on a dry mass basis.
9 A biomass according to any preceding claim, wherein said biomass comprises at least wt%, preferably at least 20 wt%, of filamentous fungus on a dry mass basis; and comprises less than 40 wt%, preferably less than 30 wt%, more preferably less than 26 wt% of filamentous fungus on a dry mass basis; and/or said biomass comprises at least 60 wt%, preferably at least 70 wt%, more preferably at least 74 wt% water; and comprises less than 90 wt%, preferably less than 80 wt%, of water; and/or the ratio of wt% of water divided by the wt% of biomass on a dry mass basis is at least 1, at least 2 or at least 2.8; and is be less than 5 or less than 4.
10 A biomass according to any preceding claim, wherein said biomass includes an acid counter-ion which was added as part of a process to adjust pH in the preparation of the biomass.
11 A method of producing a biomass having increased whiteness and/or L*, the method comprising: (i) fermenting cells of a filamentous fungus to produce a biomass comprising said filamentous fungus; and (ii) adjusting the pH of the biomass to increase the whiteness and/or L* of the biomass.
12 A method according to claim 11, wherein the biomass produced has any feature of the biomass of any of claims 1 to 11.
13 A method according to claim 11 or claim 12, wherein, in step (i), filamentous fungus is fermented in a receptacle in the presence of a fermentation medium which, at a first time, has a pH of at least 5.5 and, in step (i), fermentation is undertaken at a first temperature of less than 35°C; after elapse of a time after said first time, the temperature at which fermentation is undertaken is increased to a second temperature, wherein the difference between the first and second temperatures is at least 15°C and less than 30°C and the second temperature is at least 45°C.
14 A method according to any of claims 11 to 13, wherein, in step (ii), the pH of the biomass and/or fermentation medium is adjusted after step (i), after said first time.
A method according to any of claims 11 to 14, wherein the pH is adjusted by addition of acid, for example selected from: lactic, acetic, phosphoric, ascorbic, pyruvic, citric, formic, nitric and carbonic acids.
16 A method according to any of claims 11 to 15, wherein, in step (ii), the pH of the biomass and/or fermentation medium is lowered so the difference between the pH before lowering and the pH after lowering is at least 1.0, 2.0 or 2.5 pH units; and/or the pH of the biomass and/or fermentation medium after lowering is less than 5.0, or less than 4.5.
17 A method according to any of claims 11 to 16, wherein there is both adjustment of pH and increase of the temperature of the fermentation from said first temperature to said second temperature.
18 A method according to any of claims 11 to 17, wherein, after step (ii), the method comprises treating the biomass to reduce the level of water associated with the biomass.
19 A method according to any of claims 11 to 18, wherein said treatment of the biomass to increase whiteness and/or L* is undertaken at or downstream of a fermenter in which cells of the filamentous fungus are fermented in step (i).
A method according to any of claims 11 to 19, wherein step (ii) is undertaken on a biomass which includes greater than 75 wt%, greater than 80 wt%, or greater than 85 wt% 20 water.
21 A biomass produced in said method of any of claims 11 to 20.
22 The use of an acid and/or an increased temperature to increase whiteness and/or increase L" of a biomass produced by fermentation.
23 A product incorporating a biomass according to any of claims 1 to 10 or 21.
24 A product according to claim 23, wherein said product is a foodstuff of a non-food.
A product according to claim 23 or claim 24, wherein said product is a dairy product or a vegetarian or vegan meat-substitute.
26 A method of making a product of any of claims 23 to 25, wherein the method comprises: (i) selecting a biomass as described in any of claims 1 to 10 or 21; and (ii) contacting the biomass with other ingredients to define the product.