An electrospun fibre

Abstract

The present invention is directed towards an electrospun fibre comprising a protein isolate derived from Brewer's Spent Grain or Distiller's Spent Grain. The invention also encompasses a material comprising a plurality of such electrospun fibres, and a method of producing the electrospun fibre(s).

Description

[0001]AN ELECTROSPUN FIBRE FIELD OF THE INVENTION The present invention relates to an electrospun fibre comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, a material formed from a plurality of such fibres, and a method of producing the electrospun fibre. BACKGROUND Electrospinning is a technique used to produce fibres of micrometre-scale diameter. The fibres typically demonstrate advantageous, and often tuneable, mechanical properties, and can be functionalised for different purposes including filtration, textiles, and medical and cosmetic composites. The technique is attractive due to the relative ease of production of the fibres using a simple, cost- effective and versatile set-up. Electrospun fibres are formed through the application of a voltage across a polymer solution or melt. The use of synthetic polymers to produce synthetic fibres is advantageous due to the ease at which property modification of the fibre can be achieved. However, in recent years, focus has shifted to identifying non- synthetic bio-based polymers for use in the formation of electrospun fibres, especially biodegradable bio-based polymers, with natural bio-functionalities. SUMMARY OF INVENTION According to a first aspect of the present invention, there is provided an electrospun fibre comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’ Spent Grain. According to a second aspect of the present invention, there is provided a material comprising a plurality of electrospun fibres, each electrospun fibre comprising a protein isolate derived from Brewer’s spent Grain or Distiller’s Spent Grain. According to a third aspect of the present invention, there is provided a process for producing an electrospun fibre comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, or a material comprising a plurality of electrospun fibres, each electrospun fibre comprising a protein isolate derived from Brewer’s spent Grain or Distiller’s Spent Grain, the process comprising: (a) providing a spinning solution comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain; (b) electrospinning the spinning solution to produce the electrospun fibre(s). According to a fourth aspect of the present invention, there is provided an electrospun fibre comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, or a material comprising a plurality of electrospun fibres, each electrospun fibre comprising a protein isolate derived from Brewer’s spent Grain or Distiller’s Spent Grain, the electrospun fibre being produced by a process comprising: (a) providing a spinning solution comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain; (b) electrospinning the spinning solution to produce the electrospun fibre(s). According to a fifth aspect of the present invention, there is provided a use of Brewer’s Spent Grain or Distiller’s Spent Grain, preferably a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, in the production of an electrospun fibre. DETAILED DESCRIPTION The present inventors have surprisingly and advantageously found that Brewer’s Spent Grain or Distiller’s Spent Grain can be used to produce electrospun fibres. Such electrospun fibres are a sustainable alternative to synthetic electrospun fibres. The novel electrospun fibres according to the present invention are formed using an abundant by-product of the brewing industry, Brewer’s Spent Grain, or an abundant by-product of ethanol production, Distiller’s Spent Grain. Accordingly, production of such electrospun fibres taps into an already existing supply chain (e.g. breweries or ethanol distilleries), and makes use of a waste-feedstock that is widely available and low-cost. The electrospun fibres according to the present invention, and materials comprising such, are therefore an advantageous sustainable non-synthetic and biodegradable alternative to electrospun fibres formed of synthetic materials. The electrospun fibres and materials according to the present invention find use in many fields and technology areas. Although electrospinning of protein derived from certain plant sources is known, it is particularly surprising and advantageous that Brewer’s Spent Grain or Distiller’s Spent Grain, and protein derived therefrom, can be utilised to produce electrospun fibres. Brewer’s Spent Grain or Distiller’ Spent Grain is not a pure grain, but a waste feedstock, an unwanted by-product of beer or ethanol production. Prior to use in the present invention, the grains have already been subjected to highly intensive brewing or distillation processes. It was unexpected that Brewer’s Spent Grain or Distiller’ Spent Grain could provide a suitable protein feedstock for electrospinning, since it would have been expected that the intensive processing would cause unpredictable protein degradation, such as hydrolysis and / or denaturing of the proteins. The fact proteins derived from Brewer’s Spent Grain or Distiller’ Spent Grain can be used to form electrospun fibres could not have been predicted. It is therefore very surprising that electrospun fibres may be produced from Brewer’s Spent Grain or Distiller’ Spent Grain. Furthermore, plant sources differ in terms of their protein composition. The protein composition obtained from two different plants sources will not be the same. As used herein, the term ‘Brewer’s Spent Grain or Distiller’s Spent Grain’ refers to the protein-containing grain by-product of beer (Brewer’s) or spirit (Distiller’s) production, such as whiskey, in which a grain is utilised in a fermentation process. Distiller’s Spent Grain may also refer to the protein-containing grain by-product of ethanol biofuel production. Brewer’s Spent Grain typically comprises barley grain, typically comprising protein, lignin, lipid, and cellulose, and optionally other grain(s) introduced during the brewing process, such as oats, wheat and / or rye. The Brewer’s Spent Grain may further comprise additional by-products as a result of the processes to which it has been subjected, for example, excess sugars that invite decomposition via bacteria and / or fungal growth within the Brewer’s Spent Grain, and / or enzymes such as amylase utilised in the brewing process and capable of producing more sugars. Distiller’s Spent Grain typically comprises barley, rice, wheat, rye and / or corn grain, preferably barley grain, typically comprising protein, lignin, lipid and cellulose, and optionally other grain(s) introduced during the fermentation process. The Distiller’s Spent Grain may further comprise additional components as a result of the processes to which it has been subjected, for example, insoluble fibrous components and / or excess sugars that invite decomposition via bacteria and / or fungal growth within the Distiller’s Spent Grain and / or enzymes such as amylase utilised in the distillation process and capable of producing more sugars. Typically, Brewer’s Spent Grain or Distiller’s Spent Grain may comprise 5 to 40 wt.% protein, preferably 5 to 35 wt.% protein, or 10 to 30 wt.% protein, or 12 to 30 wt.% protein, based on the dry weight of Brewer’s Spent Grain or Distiller’s Spent Grain. Typically, Brewer’s Spent Grain or Distiller’s Spent Grain may comprise 5 to 40 wt.% lignin, preferably 11 to 32 wt.% lignin, based on the dry weight of Brewer’s Spent Grain or Distiller’s Spent Grain. Typically, Brewer’s Spent Grain or Distiller’s Spent Grain may comprise 1 to 15 wt.% lipid, based on the dry weight of Brewer’s Spent Grain or Distiller’s Spent Grain. Typically, Brewer’s Spent Grain or Distiller’s Spent Grain may comprise 10 to 80 wt.% cellulose, such as 20 to 60 wt.% cellulose, preferably 23 to 60 wt.% cellulose, based on dry weight of the Brewer’s Spent Grain or Distiller’s Spent Grain. As referred to herein, the ‘cellulose’ of the Brewer’s Spent Grain or Distiller’s Spent Grain also encompasses any hemi-cellulose and starch present in the Brewer’s Spent Grain or Distiller’s Spent Grain. Preferably, at least 90% of the Brewer’s Spent Grain is a barley grain by-product. Brewer’s Spent Grain may be obtained directly from breweries. Distiller’s Spent Grain may be obtained directly from distilleries or ethanol biofuel plants. Brewer’s Spent Grain or Distiller’s Spent Grain may be provided in a wet or dry form. Distiller’s Spent Grain encompasses wet distiller’s grains (WDG) and dried distiller’s grains with solubles (DDGS). Preferably, Brewer’s Spent Grain or Distiller’s Spent Grain comprises barley grains. Brewer’s Spent Grain or Distiller’s Spent Grain may consist of barley grains as the grain source. By the term ‘protein isolate’ as used herein is meant a protein composition extracted from Brewer’s Spent Grain or Distiller’s Spent Grain, that has been isolated from non-protein components of Brewer’s Spent Grain or Distiller’s Spent Grain, preferably by the methods defined herein. The protein isolate may comprise a complex mixture of proteins. The protein isolate has a protein composition that depends on the protein composition of Brewer’s Spent Grain or Distiller’s Spent Grain . The protein isolate therefore comprises a complex mixture of proteins having amino acid sequences that are unique to the use of Brewer’s Spent Grain or Distiller’s Spent Grain as the protein source. This means that the protein isolate is particularly suited to the process of electrospinning and the production of electrospun fibres as discussed herein. The electrospun fibre according to the present invention comprises a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. The electrospun fibre according to the present invention may consist of the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. The protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain may be the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain obtained from a single extraction process, for example using an alcohol extractant or an alkaline extractant as disclosed herein. Alternatively, the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain may be a combination of two protein isolates derived from Brewer’s Spent Grain or Distiller’s Spent Grain, each being a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, but obtained by a different extraction process, for example a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain obtained using an alcohol extractant and a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain obtained using an alkaline extractant, as disclosed herein. If the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain is a combination of two protein isolates derived from Brewer’s Spent Grain or Distiller’s Spent Grain, each protein isolate is preferably a protein isolate derived from Brewer’s Spent Grain. Preferably, the electrospun fibre according to the present invention comprises a protein isolate derived from Brewer’s Spent Grain. The protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain of the electrospun fibre according to the present invention may comprise prolamins, preferably hordeins. The protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain may further comprise albumins, globulins, and / or glutelins. Preferably, the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain comprises hordeins. The presence of hordeins in the protein isolate may be confirmed by SDS-page (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) as described herein, a technique known for the separation of proteins by molecular weight from samples and mixtures. The protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain of the electrospun fibre according to the present invention may comprise two or more of hordeins, globulins, glutelins and / or albumins. The protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain may comprise at least hordeins in combination with glutelins, globulins, and / or albumins. The hordeins may be present in an amount of from 50 wt% or more of the protein isolate, such as 60 wt% or more, or 70 wt% or more of the protein isolate. Hordeins may be present in an amount of from 50 wt% or more of the electrospun fibre, such as 60 wt% or more, or 70 wt% or more of the electrospun fibre. If the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain comprises hordeins in combination with globulins, glutelins and / or albumins, the hordeins may be present in an amount of from 50 wt% or more of the protein isolate, such as 60 wt% or more, or 70 wt% or more of the protein isolate. Accordingly, where the electrospun fibre according to the present invention is formed only of the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, the hordeins may be present in an amount of from 50 wt% or more of the electrospun fibre, such as 60 wt% or more, or 70 wt% or more of the electrospun fibre. The proteins making up the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain of the electrospun fibre according to the present invention, as described herein, may each have a molecular weight falling within the range of 10 to 100 kDa, such as 15 to 100 kDa, or 15 to 90 kDa, or 17 to 70 kDa. The proteins making up the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain of the electrospun fibre according to the present invention, as described herein, may each have a molecular weight falling within the range of 17 to 100 kDa, or 20 to 90 kDa, or 30 to 80 kDa. The molecular weights of the proteins derived from Brewer’s Spent Grain or Distiller’s Spent Grain forming the protein isolate may be distributed across this range. The molecular weight and / or molecular weight range may be identified by SDS- page (sodium dodecyl sulfate-polyacrylamide gel electrophoresis), a technique known for the separation of proteins by molecular weight from samples and mixtures, and optionally followed by the western blot analytical technique. In particular, in the context of the present invention, protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain (obtained as described herein) was boiled in a laemmli buffer (0.125M tris-HCl, pH 6.8, 4% w / v sodium dodecyl sulfate, 20% v / v glycerol, 1% w / v bromophenol blue and 0.5% 2-mercaptoethanol) and loaded onto a pre-cast 4-15% v / v polyacrylamide gel (Mini-PROTEAN® TGX™ Precast Protein Gels, 15-well, 15 μl #4561086). Samples were subjected to electrophoresis at a constant voltage of 180V. Protein bands were visualised using coomassie blue stain and de-stained in dH2O. Samples were compared to the Precision Plus Protein All Blue (supplied by BioRad) standard protein ladder simultaneously run to quantify the molecular weight. The electrospun fibre according to the present invention preferably has a thread- like structure. The electrospun fibre according to the present invention may have a micrometre- scale average diameter or width. The average diameter or width of the electrospun fibre may be from 10 nm (0.01 μm) to 20 μm, such as from 0.1 to 20 μm, or from 0.1 to 15 μm, such as from 0.5 to 15 μm, or 0.5 to 12 μm, or even from 1 to 12 μm, or from 1 to 10 μm, or 1 to 8 μm. This is measured using scanning electron microscopy (SEM). In the context of the present invention, the average electrospun fibre diameter or width was taken by measuring the diameter or width of 50 fibres chosen at random across 5 different scanning electron microscopy images. The diameter or width was measured at a random point along each fibre. The average diameter or width refers to the mean diameter or width. For the scanning electron microscopy, a sample of the electrospun fibres was coated with a thin layer of gold Au (of several nanometers). Scanning electron microscopy was performed using an FEI Inspect F device to image the morphology of the sample in vacuum. A 5 kV accelerating voltage was used. Optionally, the electrospun fibre of the present invention may consist only of the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. Optionally, the electrospun fibre according to the present invention may further comprise a polymer other than the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. This polymer is ‘spinnable’, in that it is suitable for use in electrospinning - it can be subjected to electrospinning and form an electrospun fibre. Suitable polymers include proteins derived from plant sources other than Brewer’s Spent Grain or Distiller’s Spent Grain. The plant source may be a plant or crop, such as a cereal or legume, or a crop residue. The polymer may be derived from oat, rye, corn, sorghum, wheat, pea or soybean, or combinations thereof. Suitable polymers include proteins such as prolamins, and / or glutelins. The polymers may be protein extracts and / or protein isolates. Suitable polymers include proteins such as zein, gliadins, secalins, kafirins, avenins and glutenins, or combinations thereof, in particular zein, gliadins, and glutenins, or combinations thereof. Zein may be derived from corn, whilst gliadins and glutenins may be derived from wheat. Secalins may be derived from rye. Kafirin may be derived from sorghum and avenin may be derived from oats. Suitable polymers also include polyethylene oxide, polyethylene glycol and other polymers, or combinations thereof. Preferably, if the electrospun fibre according to the present invention further comprises a polymer other than the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, the polymer is one or more protein, preferably selected from prolamins, and / or glutelins, more preferably zein, gliadins, secalins, kafirins, avenins and glutenins, or combinations thereof, more preferably zein, gliadins and / or glutenins, or a combination thereof, more preferably zein. If the electrospun fibre according to the present invention further comprises a polymer other than the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, the electrospun fibre may comprise from 0.1 to 50 wt% of the spinnable polymer other than the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, such as from 1 to 30 wt%. Optionally, the electrospun fibre comprises less than 0.1% of a polymer other than the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. Optionally, the electrospun fibre according to the present invention may not comprise any additional polymer, i.e., polymer other than the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. The only polymer may be the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. It is unexpected that no additional polymer is required to enable the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain to be spinnable, i.e. suitable for use in electrospinning. As detailed above, a polymer, including other proteins, may be introduced if desired, but this is not a requirement to achieve the electrospun fibre according to the present invention. Optionally, a crosslinker may be used in the formation of the electrospun fibre according to the present invention. The electrospun fibre according to the present invention may therefore optionally comprise the reaction product of the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain and a crosslinker. One or more crosslinker may be utilised. Suitable crosslinkers include, but are not limited to: citric acid, tannic acid, formaldehyde, urea, glutaraldehyde, or combinations thereof. During formation of the electrospun fibre according to the present invention, the crosslinker reacts with the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain to form a crosslinked protein isolate structure, in which the protein isolate is linked via the crosslinker or a reactive moiety of the crosslinker, dependent on the type of crosslinking occurring. The crosslinker has reactive group(s) which interact with the protein isolate. The reactive moiety of a crosslinker is the moiety that forms part of the crosslinked protein isolate structure. It is a moiety retained in the crosslinked structure once the reactive groups of the crosslinker have interacted with the protein isolate. For example, the chemical formula of citric acid is CO2HCH2C(CO2H)(OH)CH2CO2H. Citric acid may crosslink via hydrogen bond donation or acceptance, the formation of ion bridges from the conjugate base, or by covalent bonding through the reactive groups of the crosslinker as an electrophile or as a nucleophile. Suitable crosslinkers also include enzymes, for example an enzyme selected from transglutaminase, a lysyl oxidase and a laccase, or combination thereof. Preferably, the enzyme is transglutaminase, such as a non-animal derived transglutaminase, or a microbial transglutaminase such as a bacterial transglutaminase. A suitable transglutaminase is available under the tradename Stabizym®, such as Stabizym® TGL. When an enzyme is utilised as the crosslinker, the enzyme facilitates the crosslinking of the protein isolate itself. Typically, the protein isolate is linked together through formation of bonds between reactive moieties of the protein isolate. A crosslinked protein isolate is formed. In contrast to the other crosslinkers noted above, an enzyme does not form part of the crosslinked protein isolate structure. The enzyme remains unchanged. An enzyme may be used as a crosslinker in addition to one or more of the crosslinkers listed above. The enzyme may be accompanied by a metal salt, such as a calcium salt, for example Ca(OH)2, that enhances the effect of the enzyme. For example, an enzyme such as transglutaminase may be accompanied by a metal salt, such as a calcium salt, for example Ca(OH)2. The enzyme acts to catalyse the formation of bonds between the protein isolate itself to form a crosslinked protein structure. For example, where a transglutaminase is utilised, the enzyme catalyses the formation of isopeptide bonds between carboxyamide groups and amine groups of the protein isolate. Accordingly, the electrospun fibre according to the first aspect of the present invention may comprise a reaction product of a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain and a crosslinker, the reaction product comprising a protein isolate crosslinked by isopeptide bonds. The crosslinker may be introduced into the spinning solution, introduced via a separate spinning solution, introduced during electrospinning (through atmospheric crosslinking using a vapourised crosslinker) or introduced following formation of the electrospun fibre according to the present invention. Where the crosslinker is an enzyme, the crosslinker may be introduced into the spinning solution, introduced via a separate electrospinning solution, or introduced following formation of the electrospun fibre according to the present invention. When present, the electrospun fibre according to the present invention may comprise any suitable amount of one or more crosslinker. The electrospun fibre may comprise from 0.05 to 20 wt% of one or more crosslinker. Optionally, the electrospun fibre according to the present invention may further comprise one or more additional components. Such additional components may improve the properties of the electrospun fibre. Suitable additional components include, but are not limited to: plasticiser such as glycerol and sorbitol; nano- particles such as nano-particles of silica, hydroxyapatite and biochar; oils and waxes such as epoxidised oils, carnauba waxes and beeswaxes; cellulose such as nano cellulose, carboxy cellulose and methyl cellulose; and fillers such as minerals. The one or more additional components may be introduced into the spinning solution. When present, the electrospun fibre according to the present invention may comprise any suitable amount of one or more additional components. The electrospun fibre may comprise from 0.05 to 50 wt% of one or more additional components. The electrospun fibre according to the present invention may comprise from 50 wt% or more of the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, such as 60 wt.% or more, such as 70 wt.% or more, or 80 wt.% or more, such as 90 wt.% or more. The electrospun fibre according to the present invention may be formed of the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain as described herein, optionally a polymer other than the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, and optionally a crosslinker and / or one or more additional components. Alternatively, the electrospun fibre according to the present invention may have a core-shell structure. The outer (shell) of the electrospun fibre may comprise the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain as described herein, and the inner (core) of the electrospun fibre may comprise a spinnable protein other than the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. The electrospun fibre according to the present invention may be used in a fabric; in a non-woven material or non-woven textile, for example for insulation, felt or down alternatives, or mattress fillers; in a woven material or woven textile; in a structural scaffold, for example for cell growth or biomedical uses; a filter; or as a protein-alternative for foodstuffs. According to a second aspect of the present invention, there is provided a material comprising of a plurality of electrospun fibres, each electrospun fibre being an electrospun fibre according to the first aspect of the present invention, including all preferred and optional features of the electrospun fibres as detailed herein. By plurality as used herein is meant ‘two or more’. The material according to the second aspect of the present invention may be a fabric; a non-woven material or non-woven textile, for example for insulation, felt or down alternatives, or mattress fillers; a woven material or woven textile; a structural scaffold, for example for cell growth or biomedical uses; a filter; or a protein-alternative for foodstuffs. The material according to the second aspect of the present invention also includes the collection of electrospun fibres according to the present invention producing following electrospinning, typically collected as a mat of electrospun fibres according to the first aspect of the present invention. The form of this collection of electrospun fibres can be altered, for example, through changing the type of collector. For examples, statis, rotating, mandrel, water bath, wire, or specially designed collectors produce collections of electrospun fibres of different specific conformations. The term ‘non-woven’ as used herein refers to a material or textile in which the electrospun fibres have been bonded together by entangling the electrospun fibres, optionally a material or textile in which the electrospun fibres have been bonded together, for example, by chemical, mechanical, or solvent treatment. The term ‘woven’ as used herein refers to a material or textile in which the electrospun fibres have been knitted or woven (weaved) together. A crosslinker may also be utilised in the formation of the material according to the second aspect of the present invention. The material according to the present invention may therefore comprise the reaction product of a crosslinker and the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain of the electrospun fibres. One or more crosslinkers may be utilised. Suitable crosslinkers include, but are not limited to: citric acid, tannic acid, formaldehyde, urea, glutaraldehyde, an enzyme, or combinations thereof, as described above. The crosslinker reacts with the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain of the electrospun fibres to form a crosslinked structure as discussed above. The crosslinker may be utilised following formation of the electrospun fibres or material. The electrospun fibres or material may be introduced into a solution comprising said crosslinker to allow for crosslinking to occur post-fabrication of the electrospun fibres. The material according to the second aspect of the present invention may further comprise additional fibre(s) and / or material(s), for example to form blended and / or layered material(s), or material(s) formed of blended and / or layered fibres. The additional fibre(s) and / or material(s) may be attached to, or integrated into, the material according to the present invention. Suitable examples of additional fibre(s) and / or material(s) include, but are not limited to: those formed from spinnable polymers. Suitable spinnable polymers may be polymers other than the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, as described herein. Suitable spinnable polymers include polyethylene oxide, polyethylene glycol and other spinnable polymers, or combinations thereof. Such spinnable polymers are well known in the art. Other spinnable polymers are as described herein. Other spinnable polymers include proteins derived from plant sources other than Brewer’s Spent Grain or Distiller’s Spent Grain. Other spinnable polymers include proteins such as prolamins and / or glutelins, such as zein, gliadins, secalins, kafirins, avenins and glutenins, or combinations thereof. The polymers may be protein extracts and / or protein isolates. Suitable polymers include proteins such as zein, gliadins and glutenins, or combinations thereof. Zein may be derived from corn, whilst gliadins and glutenins may be derived from wheat. Secalins may be derived from rye. Kafirins may be derived from sorghum. Avenins may be derived from oats. Composite or layered materials may be formed. The additional fibre(s) and / or material(s) may be formed through electrospinning a solution of such at the same time as electrospinning the spinning solution comprising the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, for example to form a blended material, or may be electrospun onto a material formed of a plurality of electrospun fibres comprising the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, for example to create a layered material. The material according to the second aspect of the present invention may further comprise one or more topcoat layers. A topcoat layer may impart further advantageous properties, such as water repellence, to the material. The electrospun fibres or materials according to the present invention may advantageously provide increased moisture vapour transport, increased fabric breathability, enhanced toxic chemical resistance, and have the ability to form blended and layered fibres and / or materials. According to a third aspect of the present invention, there is provided a process for producing an electrospun fibre according to the first aspect of the present invention, or a material according to the second aspect of the present invention, the process comprising: (a) providing a spinning solution comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain; (b) electrospinning the spinning solution to produce the electrospun fibre(s). According to a fourth aspect of the present invention, there is provided an electrospun fibre according to the first aspect of the present invention, or a material according to the second aspect of the present invention, the electrospun fibre or material being produced by a process comprising: (a) providing a spinning solution comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain; (b) electrospinning the spinning solution to produce the electrospun fibre(s). Step (a) Preferably, the spinning solution comprises a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain and a solvent. Preferably, the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain is dissolved in the spinning solution. Preferably, the spinning solution comprises a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain and a solvent, and the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain is dissolved in the solvent. Any suitable solvent may be utilised. Preferably, the solvent is a solvent having reduced environmental impact compared to common solvents such as DCM, toluene or chloroform used for electrospinning. Advantageously, the use of harmful solvents such as DCM, chloroform or toluene, typically used for electrospinning, can be avoided in the formation of the electrospun fibres according to the present invention. Contrary to a significant number of other spinnable polymers, the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain is soluble in less harmful solvents. One or more solvent may be utilised. Suitable solvents for the spinning solution include, but are not limited to: polar aprotic solvents including dimethyl sulfoxide (DMSO) and acetone; organic solvents including acids and alcohols; water including deionised water (dH2O); isotonic salt solutions including phosphate buffer saline; inorganic solvents; and combinations thereof. Suitable polar aprotic solvents include DMSO and acetone. Suitable organic solvents include acids such as acetic acid, and alcohols such as ethanol. Preferably, the solvent for the spinning solution is selected from: water including deionised water; polar aprotic solvents including dimethyl sulfoxide (DMSO) and acetone; organic solvents such as acids including acetic acid and alcohols including ethanol; isotonic salt solutions including phosphate buffered saline; and combinations thereof. More preferably, the solvent for the spinning solution is selected from: water including deionised water; acetic acid; ethanol; phosphate buffered saline, or combinations thereof. More preferably, the solvent for the spinning solution is selected from an organic solvent, such as an acid including acetic acid and alcohol including ethanol, in combination with water or an isotonic salt solution, such as phosphate buffered saline. More preferably, the solvent for the spinning solution is selected from 25 to 100%, or 30 to 100%, such as 40 to 100%, or 25 to 60%, such as 30 to 60% organic solvent, such as an acid including acetic acid and alcohol including ethanol, in combination with water, including deionised water, or an isotonic salt solution, including phosphate buffered saline. More preferably the solvent for the spinning solution is selected from an organic solvent such as an acid including acetic acid or an alcohol including ethanol. More preferably, the solvent for the spinning solution is selected from: acetic acid and water (including deionised water), or the combination thereof, preferably the combination thereof: and ethanol and phosphate buffered saline, or the combination thereof, preferably the combination thereof. More preferably, the solvent for the spinning solution is selected from: acetic acid and water (including deionised water), or the combination thereof (for example, 25 to 100% acetic acid, or 30 to 100% acetic acid, such as 40 to 100% acetic acid, or 60 to 100% acetic acid, or 25 to 60% acetic acid, or 30 to 60% acetic acid, such as 30 to 50% acetic acid), preferably the combination thereof: and ethanol (and phosphate buffered saline, or the combination thereof (for example, 25 to 100% ethanol, or 30 to 100% ethanol, such as 40 to 100% ethanol, or 30 to 60% ethanol), preferably the combination thereof. More preferably, the solvent for the spinning solution is selected from: acetic acid (25 to 100%, such as 30 to 100%, 40 to 100% or 60 to 100%, or 25 to 60%, or 30 to 60%, or 30 to 50% in dH2O) or ethanol (25 to 100%, or 30 to 100%, or 40 to 100 %, or 30 to 60% in phosphate buffered saline). More preferably, the solvent for the spinning solution is acetic acid or ethanol. The spinning solution may comprise any suitable amount of protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. Preferably, the spinning solution comprises 5 to 50 wt%, preferably 30 to 50 wt% protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. The spinning solution may comprise 10 to 50 wt%, or 10 to 45 wt%, or 10 to 40 wt%, such as 20 to 35 wt%, or 20 to 30 wt%. This amount refers to the total amount of protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. Optionally, the spinning solution may consist of the protein isolate derived from Brewer’s Spent Grain and the solvent. The protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain of the spinning solution may comprise prolamins, preferably hordeins. The protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain of the spinning solution may further comprise albumins, globulins and / or glutelins. Preferably, the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain of the spinning solution comprises hordeins. The protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain of the spinning solution may comprise two or more of prolamins selected from hordeins, globulins, glutelins and / or albumins. Preferably, the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain of the spinning solution comprises at least hordeins in combination with globulins, glutelins and / or albumins. If the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain comprises hordeins in combination with globulins, glutelins and / or albumins, the hordeins may be present in an amount of from 50 wt% or more of the amount of protein isolate present in the spinning solution, such as 60 wt% or more, or 70 wt% or more of the protein isolate present in the spinning solution. The protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain of the spinning solution may be made up of proteins derived from Brewer’s Spent Grain or Distiller’s Spent Grain, each having a molecular weight falling within the range of 10 to 100 kDa, such as 15 to 100 kDa, or 17 to 70 kDa. The protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain of the spinning solution may be made up of proteins derived from Brewer’s Spent Grain or Distiller’s Spent Grain, each having a molecular weight falling within the range of 17 to 100 kDa, or 20 to 90 kDa, or 30 to 80 kDa. The molecular weights of the proteins derived from Brewer’s Spent Grain or Distiller’s Spent Grain forming the protein isolate may be distributed across this range. The molecular weight and / or molecular weight range may be measured as described herein. Preferably, the spinning solution comprises a protein isolate derived from Brewer’s Spent Grain. As discussed herein, the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain of the spinning solution may be a combination of protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain obtained using different extraction procedures, for example, protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain obtained using an alcohol extractant and protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain obtained using an alkaline extractant. To form the spinning solution, the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain and solvent are combined. The protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain dissolves in the solvent to form the spinning solution. This may take at least 2 hours, such as from 2 to 74 hours, or from 12 to 48 hours, such as 24 hours. This may take place at ambient temperature. To speed up dissolution, the temperature may be raised to 60 °C for up to 2 hours. Preferably, the solution is subjected to continuous stirring during this time. By the term "ambient temperature" as used herein is meant a temperature of from 10 to 35 °C, typically 15 to 25 °C. Ambient temperature is encompassed by the broader definition of "ambient conditions", which refers to the normal range of conditions of the surrounding environment to which the composition is exposed, i.e. the range of temperatures, pressures and atmospheric conditions to which the composition is exposed during use, storage and otherwise. This includes solar radiation including electromagnetic radiation of X-rays, ultraviolet (UV) and infrared (IR) radiation. Typically, ambient conditions include a temperature of from 10 to 35 °C, a pressure of from 20 to 100 kPa, and the environment is typically an oxygen-containing atmosphere. Preferably, the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain is combined with the solvent when in dry form. By ‘dry form’ for the protein isolate is meant the protein isolate comprising 5 to 20 wt.% moisture content, such as 5 to 15 wt.% moisture content, or 7 to 12 wt.% moisture content, for example less than 20 wt.% moisture content, preferably less than 15 wt.% moisture content, or less than 12 wt.% moisture content. More preferably, the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain is combined with the solvent in dry, shredded form. Such a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain may be obtained manually or in a high-speed shredder, ground using a pestle and mortar, or using a ball mill. The protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain may be in the form of a powder when combined with the solvent. By shredded form for the protein isolate is meant a form of the protein isolate of Brewer’s Spent Grain or Distiller’s Spent Grain of larger surface area, for example reduced in particle size, such as a powder. The powder may have an average particle size of 250 μm or more. Optionally, the spinning solution may further comprise a crosslinker and / or one or more additional components as discussed above in relation to the electrospun fibre according to the present invention. The crosslinker and / or one or more additional components may be combined with the solvent, before, at the same time as, or after, the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. The crosslinker and / or one or more additional components may be present in the spinning solution in an amount of from 0.05 %w / w to 20% w / w. Optionally, the spinning solution may further comprise a polymer other than the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, as described herein. The polymer may be combined with the solvent, before, at the same time as, or after, the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. The polymer other than the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain may be present in the spinning solution in an amount of from 0.1 to 50 wt%. Once the spinning solution has been formed, the spinning solution is electrospun to form the electrospun fibre according to the first aspect of the present invention or the material according to the second aspect of the present invention. The technique of electrospinning is well known in the art. Electrospun fibres are formed through exposure of the spinning solution to a high voltage. It is known in the art that different setups can be used to carry out the electrospinning of the spinning solution. For example, for the present invention, the spinning solution may be placed into a syringe with a blunt tip needle attached. The syringe may be placed into a syringe pump with a set flow rate and the spinning solution fired from the syringe across a voltage. The voltage may be slowly increased until the spinning solution is drawn towards a charged collector. The voltage may then be tuned until a visible Taylor cone of the spinning solution forms (a conical shape of solution from which a jet of charged spinning solution droplets emanates above a threshold voltage). The charged spinning solution jet may then be drawn into electrospun fibres deposited at the charged collector. During electrospinning, the solvent is evaporated, the electrospun fibre is formed from the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, and optional crosslinker and / or one or more other components. The electrospinning may be carried out at any suitable temperature, preferably ambient temperature, and preferably under ambient conditions. The syringe may have any appropriate volume. Preferably, the syringe has a volume of 10 mL. The needle of the syringe may have any appropriate gauge. Preferably, the needle has an 18 to 24 gauge , such as a 21 gauge. The voltage applied may be any appropriate voltage. Preferably, the voltage applied is from 8 to 30 kV, such as from 15 to 30 kV, such as from 15 to 25 kV. The tip-to-collector distance (distance from the tip of the needle to the collector) may be any appropriate distance. Preferably, the tip-to-collector distance is from 8 to 30 cm. More preferably, the tip-to-collector distance is from 10 to 20 cm, such as from 12 to 18 cm. The charged collector may be stationary or may rotate. The charged collector may have any suitable rotating speed. The rotating speed may be from stationary or may rotate at a speed of 5000 RPM or less, such as 2000 RPM or less, or 1000 RPM or less. The rotation of the charged collector may alter the alignment of the fibres collected. For the collection of fibres having increased fibre alignment, the rotating speed may be from 1000 to 5000 RPM, such as from 1000 to 2000 RPM. For collection of fibres having lower fibre alignment (non-aligned fibres), the rotating speed may be 1000 RPM or less, such as from 500 to 750 RPM. The flow rate of the spinning solution (speed extruded from the needle tip (by pump)) may be any suitable flow rate. Preferably, the flow rate is 1 to 4 mL per hour, such as from 1 to 2 mL per hour, and more preferably, 1 mL per hour. Different setups for electrospinning include core-shell electrospinning, dual electrospinning, and wet spinning. Such techniques and setups are known in the art. Optionally, after obtaining the electrospun fibre(s) or material, the electrospun fibre(s) or material may be dried by any suitable method. For example, using an oven, dehydrator, desiccator, at ambient temperature under ambient conditions, freeze dried, or dried using a vacuum oven. After drying, the electrospun fibre(s) or material may comprise less than 20 wt.% moisture content, preferably less than 15 wt.% moisture content. Additional Process Steps The process according to the third aspect of the present invention and process for forming the electrospun fibre according to the fourth aspect of the present invention, may comprise additional process steps. Prior to providing a spinning solution comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain may be obtained from Brewer’s Spent Grain or Distiller’s Spent Grain. Accordingly, the process according to the third aspect of the present invention and the process for forming the electrospun fibre according to the fourth aspect of the present invention preferably further comprises the step of obtaining a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. Preferably, the step of obtaining a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain comprises extracting protein from Brewer’s spent Grain or Distiller’s Spent Grain. Extraction of the protein from Brewer’s Spent Grain or Distiller’s Spent Grain may comprise: combination of Brewer’s Spent Grain or Distiller’s Spent Grain with an alcohol extractant and / or alkaline extractant, heating of the resulting solution(s), and separation of any insoluble component(s) of Brewer’s Spent Grain or Distiller’s Spent Grain, to provide an alcohol extract solution and / or alkaline extract solution. The alcohol extract solution will comprise all protein extracted from the Brewer’s Spent Grain or Distiller’s Spent Grain by the alcohol extractant. The alkaline extract solution will comprise all protein extracted from the Brewer’s Spent Grain or Distiller’s Spent Grain by the alkaline extractant. The protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain may be solubilised in the alcohol extract solution or alkaline extract solution. Both alcohol and alkaline extractants may be used. If this is the case, this is in separate parallel extraction processes to provide separate extract solutions. The separate extract solutions can both then be acted on with regard to precipitation as detailed below, in the context of the process according to the present invention. The protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain obtained from each extract solution (each process) may be combined and introduced into the spinning solution. Alternatively, if both alcohol and alkaline extractants are used, sequential extraction of the protein from Brewer’s Spent Grain or Distiller’s Spent Grain may occur using an alcohol extractant and then an alkaline extractant. Separate alcohol extract and alkaline extract solutions are obtained, the first resulting from extraction of protein from Brewer’s Spent Grain or Distiller’s Spent Grain with an alcohol extractant, and the second resulting from extraction of protein from the insoluble components(s) of the Brewer’s Spent Grain or Distiller’s Spent Grain separated during the extraction with the alcohol extractant. In such instances, for the alkaline extraction, reference to Brewer’s Spent Grain or Distiller’s Spent Grain in the context of extraction, in fact refers to the insoluble component(s) of Brewer’s Spent Grain or Distiller’s Spent Grain separated and retained during the previous extraction using an alcohol extractant. These insoluble component(s) may be first washed to remove any excess alcohol residual left from the alcohol extractant. For the sequential extraction discussed herein, the alcohol extract solution is obtained first, and then the alkaline extract solution is obtained (using the insoluble component(s) of the Brewer’s Spent Grain or Distiller’s Spent Grain separated and retained during the alcohol extraction process). Both the alcohol extract solution and the alkaline extract solution can then be acted on with regard to precipitation as further detailed below, in the context of the process according to the present invention. The protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain obtained by each process may be combined and introduced into the spinning solution. Suitable alcohol extractants include, but are not limited to: ethanol, iso-propyl alcohol, methanol, and propanol, or combinations thereof. The alcohol extractant may further comprise an organic solvent, such as ethyl acetate, acetone, and DMSO, or combinations thereof. The alcohol extractant may be an aqueous alcohol solution, further comprising water, which may be deionised water, and may optionally further comprise an organic solvent, such as ethyl acetate, acetone, and DMSO, or combinations thereof. Preferably, the alcohol extractant is an aqueous alcohol solution. When the alcohol extractant is an aqueous alcohol solution, the alcohol extractant may comprise 40 to 70 % alcohol by volume. The alkaline extractant may be an aqueous alkaline solution comprising an alkaline reagent and water, which may be deionised water. Preferably, the alkaline extractant is an aqueous alkaline solution. Suitable alkaline reagents include alkaline hydroxide salts, for example NaOH, KOH or Ca(OH)2. When the alkaline extractant is an aqueous alkaline solution, the alkaline extractant preferably comprises the alkaline reagent at a concentration of from 0.05 M to 1 M, such as 0.1 M. The Brewer’s Spent Grain or Distiller’s Spent Grain may be combined with the alcohol extractant or alkaline extractant at any suitable ratio. The ratio of the Brewer’s Spent Grain or Distiller’s Spent Grain to the alcohol extractant or alkaline extractant may be from 1:2 to 1:20, preferably from 1:4 to 1:10, such as from 1:4 to 1:7, and more preferably 1:6. To aid the extraction of the protein from the Brewer’s Spent Grain or Distiller’s Spent Grain, a reducing agent may be utilised. This may be introduced into the alcohol extractant or alkaline extractant prior to combination with the Brewer’s Spent Grain or Distiller’s Spent Grain. Suitable reducing agents include, but are not limited to: ȕ-mercaptoethanol, dithiothreitol, and tris [2-carboxyethyl] phosphine. The reducing agent may be present in an amount of 0.1% w / w to 5% w / w of the solution comprising the alcohol extractant or alkaline extractant, Brewer’s Spent Grain or Distiller’s Spent Grain and reducing agent. Heating of the solution resulting from the combination of the Brewer’s Spent Grain or Distiller’s Spent Grain with the alcohol extractant or alkaline extractant may be to a temperature of from 50 to 75 °C, such as from 50 to 70 °C, or from 55 to 70 °C. The solution may be heated over a period of time of from 20 to 300 minutes, preferably from 20 to 100 minutes, such as from 20 to 80 minutes. Without being bound by theory, the present inventors consider that using an alcohol extractant extracts hordeins, whilst using an alkaline extractant extracts hordeins, globulins, albumins, and / or glutelins. Preferably, extraction of the protein from Brewer’s Spent Grain or Distiller’s Spent Grain comprises: combination of Brewer’s Spent Grain or Distiller’s Spent Grain with an alcohol extractant, or alcohol and alkaline extractant, heating of the resulting solution(s), and separating of any insoluble component(s) of Brewer’s Spent Grain or Distiller’s Spent Grain to provide an alcohol extract solution, or alcohol and alkaline extract solutions as discussed herein. In the extraction of the protein from Brewer’s Spent Grain or Distiller’s Spent Grain, the insoluble component(s) may be separated by filtration and / or centrifuge separation. By ‘insoluble component(s)’ as used herein is meant any component of the Brewer’s Spent Grain or Distiller’s Spent Grain that does not solubilise in the alcohol extractant or alkaline extractant, and is thus insoluble in the resulting alcohol extract solution or alkaline extract solution. The step of obtaining a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain may then further comprise the step of precipitating the protein from solution, preferably from the alcohol extract solution and / or alkaline extract solution. This occurs following extraction of the protein from Brewer’s Spent Grain or Distiller’s Spent Grain. The protein may be precipitated from solution through cold precipitation, acid precipitation or solvent evaporation. Where an alcohol extractant has been utilised to extract the protein from Brewer’s Spent Grain or Distiller’s Spent Grain, the protein may preferably be precipitated by cold precipitation. For cold precipitation, the solution comprising the protein extracted from Brewer’s Spent Grain or Distiller’s Spent Grain may be maintained at a temperature of from 0 to 4 °C. The solution may be maintained at this temperature from a period of time of from 12 to 48 hours. The protein is thus precipitated from the solution. When an alkaline extractant has been utilised to extract the protein from Brewer’s Spent Grain or Distiller’s Spent Grain, the protein may preferably be precipitated by acid precipitation. For the acid precipitation, an acid reagent may be added to the solution comprising the protein extracted from Brewer’s Spent Grain or Distiller’s Spent Grain. The acid reagent may be selected from any suitable acid, for example, hydrochloric acid, citric acid, or acetic acid. For the acid precipitation, the acid reagent is added in an amount suitable to provide a pH of from 1 to 6, preferably 3, 4 or 5. The amount of acid reagent introduced will thus vary. Without being bound by theory, the present inventors consider that altering the pH of the solution facilitates the precipitation of different extracted prolamins, or combinations thereof. For cold precipitation and acid precipitation, following precipitation of the protein from solution, a protein suspension may be obtained. Irrespective of the extractant used to extract the protein from Brewer’s Spent Grain or Distiller’s Spent Grain, the protein may be precipitated using solvent evaporation. For solvent evaporation, the solution may be left at a temperature of from 15 to 75 °C, such as from 30 to 65 °C, or 50 °C, preferably for 1 to 5 hours, such as from 1 to 3 hours, or 2 hours, optionally under continuous stirring, until all solvent has evaporated. If solvent evaporation is used to precipitate the protein from solution, the step of isolating the protein to provide a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain as discussed below is not required. Where an alcohol extractant has been utilised to extract the protein, the protein precipitated from the alcohol extract solution may comprise hordeins. Where an alkaline extractant has been utilised to extract the protein, the protein precipitated from the alkaline extract solution may comprise hordeins, globulins, glutelins and / or albumins. The step of obtaining a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain may then further comprise isolating the protein to provide a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. This occurs following the extraction stage discussed above. Preferably, this occurs following the precipitation stage discussed above. Preferably, the step of obtaining a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain further comprises isolating the protein to provide a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. Where an alcohol extractant has been utilised to extract the protein, the protein isolate may comprise hordeins. Where an alkaline extractant has been utilised to extract the protein, the protein isolate may comprise hordeins, globulins, glutelins and / or albumins. The protein may be isolated by centrifugation. Preferably, this may be at ambient temperature, or at a temperature of from 0 to 20 °C, such as from 0 to 10°C. The centrifugation may take from 10 minutes to 1 hour, such as 30 minutes. The centrifugation may take place at 2000 to 9000 x g, preferably at 3000 x g. The protein isolate obtained after precipitating and optionally isolating the protein is a protein composition extracted from Brewer’s Spent Grain or Distiller’s Spent Grain, that has been isolated from substantially all, preferably all, of the non- protein components of Brewer’s Spent Grain or Distiller’s Spent Grain The protein isolate obtained may be made up of proteins derived from Brewer’s Spent Grain or Distiller’s Spent Grain, each having a molecular weight falling within the range of 10 to 100 kDa, such as 15 to 100 kDa, or 17 to 70 kDa. The protein isolate obtained may be made up of proteins derived from Brewer’s Spent Grain or Distiller’s Spent Grain, each having a molecular weight falling within the range of 17 to 100 kDa, or 20 to 90 kDa, or 30 to 80 kDa. The molecular weights of the proteins derived from Brewer’s Spent Grain or Distiller’s Spent Grain forming the protein isolate may be distributed across this range. The molecular weight, and / or molecular weight range may be measured as described herein. The protein isolate may then be utilised to provide a spinning solution comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, as required for step (a) of the process according to the third aspect of the present invention, or the process for forming the electrospun fibre according to the fourth aspect of the present invention. Optionally, after it is obtained, the protein isolate may be dried, i.e. after isolating to provide a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. The protein isolate may be dried by any suitable method. For example, using an oven, dehydrator, desiccator, at ambient temperature under ambient conditions, freeze dried, or dried using a vacuum oven. The dried protein isolate may then be utilised to provide a spinning solution comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, as required for step (a) of the process according to the third aspect of the present invention, or the process for forming the electrospun fibre according to the fourth aspect of the present invention. By dry or dried protein isolate is meant protein isolate comprising 5 to 20 wt.% moisture content, such as 5 to 15 wt.% moisture content, or 7 to 12 wt.% moisture content, for example less than 20 wt.% moisture content, preferably less than 15 wt.% moisture content, or less than 12 wt.% moisture content. Optionally, following drying, the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain may be shredded. This may be done manually or in a high-speed shredder, ground using a pestle and mortar, or using a ball mill. The dried and optionally shredded, protein isolate may then be utilised to provide a spinning solution comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, as required for step (a) of the process according to the third aspect of the present invention, or the process for forming the electrospun fibre according to the fourth aspect of the present invention. Preferably, the process according to the third aspect of the present invention, or the process to form the electrospun fibre according to the fourth aspect of the present invention comprises a step of obtaining a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, wherein the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain is obtained by: (1) extracting protein from Brewer’s Spent Grain or Distiller’s Spent Grain, including heating, and separating any insoluble component(s) of Brewer’s Spent Grain or Distiller’s Spent Grain; (2) precipitating the protein from solution; and (3) optionally isolating the protein; to obtain a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. For each of the stages (1) to (3), all of the preferred or optional features of each step are applicable, and may be combined. For the process of the third aspect of the present invention, or the process for forming the electrospun fibre according to the fourth aspect of the present invention, following obtaining a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain may be used to provide a spinning solution comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. A protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain obtained according to steps (1) to (3) above many be combined with another protein isolate obtained according to steps (1) to (3) above to be the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain present in the spinning solution. For example, a protein isolate obtained according to steps (1) to (3) using an alcohol extractant in step (1) and a protein isolate obtained according to steps (1) to (3) using an alkaline extractant in step (1), may be combined to form the spinning solution comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. For the process according to the third aspect of the present invention, or the process for forming the electrospun fibre according to the fourth aspect of the present invention, prior to obtaining a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, the Brewer’s Spent Grain or Distiller’s Spent Grain may be washed. This may be with an organic solvent and / or with water, such as deionised or distilled water. Preferably, the Brewer’s Spent Grain or Distiller’s Spent Grain may be washed with an organic solvent and water. Preferably, the Brewer’s Spent Grain or Distiller’s Spent Grain is washed with water, such as deionised or distiller water, at least once, more preferably more than one, such as two to five times, or two to four times, or twice. Washing of the Brewer’s Spent Grain or Distiller’s Spent Grain with water typically removes any residual or excess sugars or enzymes from the grains. Preferably, the Brewer’s Spent Grain or Distiller’s Spent Grain may be washed with an organic solvent. Suitable organic solvents include hexane or acetone. Washing of the Brewer’s Spent Grain or Distiller’s Spent Grain with an organic solvent typically removes any residual or excess oils from the grain. Preferably, the Brewer’s Spent Grain or Distiller’s Spent Grain is washed with an organic solvent at least one. For the process according to the third aspect of the present invention, or the process for forming the electrospun fibre according to the fourth aspect of the present invention, prior to obtaining a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, the Brewer’s Spent Grain or Distiller’s Spent Grain may be washed with water and washed with an organic solvent. For the process according to the third aspect of the present invention, or the process for forming the electrospun fibre according to the fourth aspect of the present invention, the Brewer’s Spent Grain or Distiller’s Spent Grain is preferably used in dry form. This is then used to obtain a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, optionally after washing of the Brewer’s Spent Grain or Distiller’s Spent Grain as discussed above. By ‘dry form’ for the Brewer’s Spent Grain or Distiller’s Spent Grain is meant Brewer’s Spent Grain or Distiller’s Spent Grain comprising less than 20 wt.% moisture content, preferably less than 15 wt.% moisture content. Brewer’s Spent Grain or Distiller’s Spent grain is typically obtained from breweries or other sources, in wet form. Using a dry form of the Brewer’s Spent Grain or Distiller’s Spent Grain helps to prevent decomposition of the grain. For the process according to the third aspect of the present invention, or the process for forming the electrospun fibre according to the fourth aspect of the present invention, the Brewer’s Spent Grain or Distiller’s Spent Grain may be used within ten days, such as within seven days, or five days, or three days of obtaining the Brewer’s Spent Grain or Distiller’s Spent Grain, if obtained directly from the source of Brewer’s Spent Grain or Distiller’s Spent Grain, such as breweries, distilleries, or ethanol biofuel plants. Alternatively, for the process according to the third aspect of the present invention, or the process for forming the electrospun fibre according to the fourth aspect of the present invention, the Brewer’s Spent Grain or Distiller’s Spent Grain may be frozen within ten days, such as within seven days, or five days, or three days of obtaining the Brewer’s Spent Grain or Distiller’s Spent Grain directly from the source, and then unfrozen for use at a later date. According to the fifth aspect of the present invention, there is provided a use of Brewer’s Spent Grain or Distiller’s Spent Grain, preferably a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, in the production of an electrospun fibre. All features of all other aspects described herein, whether preferred or optional, are applicable to the fifth aspect of the present invention. All the features contained herein may be combined with any of the above aspects and in any combination. For a better understanding of the present invention, and to show how embodiments of the same may be carried into effect, reference will now be made to the following examples. EXAMPLES Example 1 Protein Isolate A 50g of dry Brewer’s Spent Grain was washed (x2) with deionised water. The washed Brewer’s Spent Grain was added to a 300 mL aqueous alcohol solution (alcohol extractant) of 55% ethanol and 45% dH20 (1:6 ratio of Brewer’s Spent Grain to alcohol extractant), heated to 60 °C and stirred for 2 hours. The solution was then centrifuged at 4000 x g for 30 minutes at 20°C to separate insoluble component(s) of the Brewer’s Spent Grain. The insoluble component(s) were retained. The resulting solution (alcohol extract solution) was then stored at 2 °C for 12 hours (cold precipitation), before centrifugation at 2 °C for 30 minutes at 4000 x g to collect the protein isolate. The protein isolate was vacuum dried for 12 hours at ambient temperature and shredded to a fine powder using a pestle and mortar. Protein Isolate B 50g of dry Brewer’s Spent Grain (the insoluble component(s) of Brewer’s Spent Grain retained from Protein Isolate A production) was washed (x2) with deionised water (to remove excess alcohol). The washed Brewer’s Spent Grain was added to a 0.5M NaOH aqueous alkaline solution (alkaline extractant) (1:6 ratio of Brewer’s Spent Grain to alkaline extractant), heated to 60 °C and stirred for 30 minutes. The solution was then centrifuged at 20 °C (3000 x g for 30 minutes) to separate insoluble component(s) of the Brewer’s Spent Grain. The protein was then precipitated from the resulting solution (alkaline extract solution) by buffering to a pH of 4 through the addition of hydrochloric acid (8 mL of 0.5M HCl) (acid precipitation), before centrifugation at 2 °C for 30 minutes at 3000 x g to collect the protein isolate. The protein isolate was vacuum dried for 24 hours at ambient temperature and shredded to a fine powder using a pestle and mortar. A solution of 40% (w / w) protein isolate in acetic acid was formed. The protein isolate was 80% protein isolate A and 20% protein isolate B. The solution was left to stir for 1 day at ambient temperature. The spinning solution was placed in a 10 mL syringe and spun under ambient temperature and conditions using the following parameters: Flow rate: 1 mL per hour Tip-to-collector distance: 15 cm Stationary collector (collection plate) Voltage: 21.8 kV Electrospun fibres according to the present invention were formed having a diameter of 1.224 μm + / - 0.379 (measured using scanning electron microscopy). Example 2 Protein Isolate A 50g of dry Brewer’s Spent Grain was washed (x2) with deionised water. The washed Brewer’s Spent Grain was added to a 300 mL aqueous alcohol solution (alcohol extractant) of 45% iso-propyl alcohol and 55% dH20 (1:6 ratio of Brewer’s Spent Grain to alcohol extractant), heated to 60 °C and stirred for 2 hours. The solution was then centrifuged at 4000 x g for 30 minutes at 20°C to separate insoluble component(s) of the Brewer’s Spent Grain. The insoluble component(s) were retained. The resulting solution (alcohol extract solution) was then stored at 2 °C for 12 hours (cold precipitation), before centrifugation at 2 °C for 30 minutes at 4000 x g to collect the protein isolate. The protein isolate was vacuum dried for 12 hours at ambient temperature and shredded to a fine powder using a pestle and mortar. Protein Isolate B: Polymer other than the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain Zein F4400C-PHG (pharmaceutical grade) protein isolate was obtained from FloZein Products and was used without further purification. A solution of 40% (w / w) protein isolate in acetic acid was formed. The protein isolate was 60% protein isolate A and 40% protein isolate B. The solution was left to stir for 1 day at ambient temperature. The spinning solution was placed in a 10 mL syringe and spun under ambient temperature and conditions using the following parameters: Flow rate: 2 mL per hour Tip-to-collector distance: 10 cm Rotating collector speed: 750 RPM Voltage: 19 kV Electrospun fibres according to the present invention were formed having a diameter of 2.405 μm + / - 0.771 (measured using scanning electron microscopy). Example 3 Protein Isolate A 1kg of dry Brewer’s Spent Grain was washed by immersion in 5L of acetone and stirring at ambient temperature for 2 hours. Acetone was removed and remaining acetone was left to evaporate. The washed Brewer’s Spent Grain was added to a 6L aqueous alcohol solution (alcohol extractant) of 65% ethanol and 35% dH20 (1:5 ratio of Brewer’s Spent Grain to alcohol extractant), heated to 60 °C and stirred for 2 hours. The solution was then centrifuged at 4000 x g for 30 minutes at 20°C to separate insoluble component(s) of the Brewer’s Spent Grain. The insoluble component(s) were retained. The resulting solution (alcohol extract solution) was then stored at 2 °C for 12 hours (cold precipitation), before centrifugation at 2 °C for 30 minutes at 4000 x g to collect the protein isolate. The protein isolate was vacuum dried for 12 hours at ambient temperature and shredded to a fine powder using a pestle and mortar. A solution of 40% (w / w) protein isolate in acetic acid was formed. The protein isolate was 100% protein isolate A. The solution was left to stir for 1 day at ambient temperature. The spinning solution was placed in a 10 mL syringe and spun under ambient temperature and conditions using the following parameters: Flow rate: 2 mL per hour Tip-to-collector distance: 10 cm Rotating collector speed: 900 RPM Voltage: 25 kV The electrospun fibres were dried. Electrospun fibres according to the present invention were formed having a diameter of 0.719 μm + / - 0.281 (measured using scanning electron microscopy). EMBODIMENTS 1. An electrospun fibre comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. 2. The electrospun fibre according to embodiment 1, wherein the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain comprises prolamins selected from hordeins, albumins, gliadins and / or glutelins, preferably hordeins. The electrospun fibre according to embodiment 1 or 2, wherein the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain comprises two or more of prolamins selected from hordeins, albumins, glutelins, and / or gliadins, preferably at least hordeins in combination with gliadins, glutelins and / or albumins. The electrospun fibre according to any of embodiments 1 to 3, wherein the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain comprises hordeins in an amount of from 50 wt% or more of the protein isolate, such as 60 wt% or more, or 70 wt% or more of the protein isolate. The electrospun fibre according to any of embodiments 1 to 4, wherein the electrospun fibre comprises hordeins in an amount of from 50 wt% or more of the electrospun fibre, such as 60 wt% or more, or 70 wt% or more of the electrospun fibre. The electrospun fibre according to any of embodiments 1 to 5, wherein the average diameter of the electrospun fibre is from 10 nm to 20 μm, such as from 0.1 to 20 μm, or from 0.1 to 15 μm, such as from 0.5 to 15 μm, or 0.5 to 12 μm, or even from 1 to 12 μm, or from 1 to 10 μm, or 1 to 8 μm. The electrospun fibre according to any of embodiments 1 to 6, wherein the electrospun fibre comprises a reaction product of the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain and a crosslinker. The electrospun fibre according to any of embodiments 1 to 7, wherein the protein isolate is derived from Brewer’s Spent Grain. A material comprising a plurality of electrospun fibres, each electrospun fibre being an electrospun fibre according to any of embodiments 1 to 8. A process for producing an electrospun fibre according to any of embodiments 1 to 8, the process comprising: (a) providing a spinning solution comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain; (b) electrospinning the spinning solution to produce the electrospun fibre. The process according to embodiment 10, wherein in step (a), the spinning solution further comprises a solvent, and preferably wherein the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain is dissolved in the solvent. The process according to embodiment 11, wherein in step (a), the solvent is selected from: polar aprotic solvents including dimethyl sulfoxide (DMSO) and acetone; organic solvents including acids and alcohols; water including deionised water (dH2O); isotonic salt solutions including phosphate buffer saline; inorganic solvents; and combinations thereof, preferably from: polar aprotic solvents including dimethyl sulfoxide (DMSO) and acetone; water including deionised water; organic solvents such as acids including acetic acid and alcohols including ethanol; isotonic salt solutions including phosphate buffered saline; and combinations thereof, more preferably from: water including deionised water; organic solvents such as acids including acetic acid and alcohols including ethanol; isotonic salt solutions including phosphate buffered saline; and combinations thereof, , more preferably from: water including deionised water; acetic acid; ethanol; phosphate buffered saline; or combinations thereof, more preferably from an organic solvent, such as an acid including acetic acid and alcohol including ethanol, in combination with water or an isotonic salt solution, such as phosphate buffered saline, more preferably from 40 to 100% organic solvent, such as an acid including acetic acid and alcohol including ethanol, in combination with water, including deionised water, or an isotonic salt solution, including phosphate buffered saline, more preferably from: acetic acid and water, or the combination thereof, and ethanol and phosphate buffered saline, or the combination thereof, more preferably from an organic acid or alcohol, more preferably from: acetic acid (60 to 100% in dH2O) or ethanol (40 to 100 % in phosphate buffered saline), and more preferably is acetic acid or ethanol. 13. The process according to any of embodiments 10 to 12, wherein in step (a), the spinning solution comprises 5 to 50% w / w protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain. 14. The process according to any of embodiments 10 to 13, wherein the process further comprises the step of obtaining the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain by extracting protein from Brewer’s Spent Grain or Distiller’s Spent Grain. 15. The process according to embodiment 14, wherein the extraction of the protein from Brewer’s Spent Grain or Distiller’s Spent Grain includes using an alcohol extractant to provide an alcohol extract solution. 16. The process according to embodiment 14 or 15, wherein the extraction of the protein from Brewer’s Spent Grain or Distiller’s Spent Grain includes using an alkaline extractant to provide an alkaline extract solution. 17. The process according to any of embodiments 14 to 16, wherein the extraction includes a sequential extraction of the protein from Brewer’s Spent Grain or Distiller’s Spent Grain using an alcohol extractant and then an alkaline extractant to provide both an alcohol extract solution and an alkaline extract solution. 18. The process according to any of embodiments 14 to 17, wherein the extraction of the protein from Brewer’s Spent Grain or Distiller’s Spent Grain comprises heating at a temperature of from 50 to 95 °C, preferably from 55 to 95 °C, or 55 to 90 °C, such as from 55 to 85 °C, or from 55 to 80 °C, optionally for 20 to 300 minutes, preferably from 20 to 100 minutes, such as from 20 to 80 minutes. 19. The process according to any of embodiments 14 to 18, wherein extraction of the protein from Brewer’s Spent Grain or Distiller’s Spent Grain comprises separating insoluble component(s) of Brewer’s Spent Grain or Distiller’s Spent Grain, preferably by filtration and / or centrifuge separation. 20. The process according to any of embodiments 14 to 19, wherein the process further comprises the step of precipitating the extracted protein from solution, preferably by cold, acid, or solvent precipitation. 21. The process according to any of embodiments 14 to 20, wherein the process further comprises the step of isolating the protein to provide a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, preferably wherein the protein is isolated by centrifugation. 22. An electrospun fibre comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, the electrospun fibre being produced by a process according to any of embodiments 10 to 21. 23. Use of Brewer’s Spent Grain or Distiller’s Spent Grain, preferably a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, in the production of an electrospun fibre.

Claims

AMENDED CLAIMS received by the International Bureau on 04 February 2025 (04.02.2025)1. An electrospun fibre comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, wherein the protein isolate comprises hordeins.

2. The electrospun fibre according to claim 1 , wherein the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain further comprises glutelins, globulins, and / or albumins.

3. The electrospun fibre according to claim 1 or 2, wherein the protein isolate comprises hordeins in an amount of from 50 wt% or more of the protein isolate, such as 60 wt% or more, or 70 wt% or more of the protein isolate.

4. The electrospun fibre according to any of claims 1 to 3, wherein the electrospun fibre comprises hordeins in an amount of from 50 wt% or more of the electrospun fibre, such as 60 wt% or more, or 70 wt% or more of the electrospun fibre.

5. The electrospun fibre according to any of claims 1 to 4, wherein the average diameter or width of the electrospun fibre is from 10 nm to 20 pm, such as from 0.1 to 20 pm, or from 0.1 to 15 pm, such as from 0.5 to 15 pm, or 0.5 to 12 pm, or even from 1 to 12 pm, or from 1 to 10 pm, or 1 to 8 pm.

6. The electrospun fibre according to any of claims 1 to 5, wherein the electrospun fibre comprises a reaction product of the protein isolate and a crosslinker.

7. The electrospun fibre according to any of claims 1 to 6, wherein the protein isolate is derived from Brewer’s Spent Grain.

8. The electrospun fibre according to any of claims 1 to 7, wherein the electrospun fibre further comprises a polymer other than the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, preferably wherein the polymer is selected from one or more proteins.

9. A material comprising a plurality of electrospun fibres, each electrospun fibre being an electrospun fibre according to any of claims 1 to 8.

10. A process for producing an electrospun fibre according to any of claims 1 to 8, or the material according to claim 9, the process comprising:AMENDED SHEET (ARTICLE 19)(a) providing a spinning solution comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, wherein the protein isolate comprises hordeins;(b) electrospinning the spinning solution to produce the electrospun fibre(s).

11. The process according to claim 10, wherein in step (a), the spinning solution further comprises a solvent, and preferably wherein the protein isolate is dissolved in the solvent.

12. The process according to claim 11 , wherein in step (a), the solvent is selected from: polar aprotic solvents including dimethyl sulfoxide (DMSO) and acetone; organic solvents including acids and alcohols; water including deionised water (dH2O); isotonic salt solutions including phosphate buffer saline; inorganic solvents; and combinations thereof, preferably from: polar aprotic solvents including dimethyl sulfoxide and acetone; water including deionised water; organic solvents such as acids including acetic acid and alcohols including ethanol; isotonic salt solutions including phosphate buffered saline; and combinations thereof, more preferably from: water including deionised water; organic solvents such as acids including acetic acid and alcohols including ethanol; isotonic salt solutions including phosphate buffered saline; and combinations thereof.

13. The process according to any of claims 10 to 12, wherein in step (a), the spinning solution comprises 5 to 50% w / w protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain.

14. The process according to any of claims 10 to 13, wherein the process further comprises the step of obtaining the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain by extracting protein from Brewer’s Spent Grain or Distiller’s Spent Grain.

15. The process according to claim 14, wherein the extraction of the protein from Brewer’s Spent Grain or Distiller’s Spent Grain includes using an alcohol extractant to provide an alcohol extract solution.AMENDED SHEET (ARTICLE 19)16. The process according to claim 14 or 15, wherein the extraction of the protein from Brewer’s Spent Grain or Distiller’s Spent Grain includes using an alkaline extractant to provide an alkaline extract solution.

17. The process according to any of claims 14 to 16, wherein the extraction includes a sequential extraction of the protein from Brewer’s Spent Grain or Distiller’s Spent Grain using an alcohol extractant and then an alkaline extractant to provide both an alcohol extract solution and an alkaline extract solution, and both solutions are used to obtain the protein isolate.

18. The process according to any of claims 14 to 17, wherein the extraction of the protein from Brewer’s Spent Grain or Distiller’s Spent Grain comprises heating at a temperature of from 50 to 95 °C, preferably from 55 to 95 °C, or 55 to 90 °C, such as from 55 to 85 °C, or from 55 to 80 °C, optionally for from 20 to 300 minutes, preferably for from 20 to 100 minutes, such as for from 20 to 80 minutes.

19. The process according to any of claims 14 to 18, wherein extraction of the protein from Brewer’s Spent Grain or Distiller’s Spent Grain comprises separating insoluble component(s) of Brewer’s Spent Grain or Distiller’s Spent Grain, preferably by filtration and / or centrifuge separation.

20. The process according to any of claims 14 to 19, wherein the process further comprises the step of precipitating the extracted protein from solution, preferably by cold, acid, or solvent precipitation.

21. The process according to any of claims 14 to 20, wherein the process further comprises the step of isolating the protein to provide the protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, preferably wherein the protein is isolated by centrifugation.

22. An electrospun fibre comprising a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain, or material comprising a plurality of electrospun fibres, each electrospun fibre comprising a protein isolate derived from Brewer’s spent Grain or Distiller’s Spent Grain, wherein the protein isolate comprisesAMENDED SHEET (ARTICLE 19)hordeins, the electrospun fibre or material being produced by a process according to any of claims 10 to 21.

23. Use of Brewer’s Spent Grain or Distiller’s Spent Grain, preferably a protein isolate derived from Brewer’s Spent Grain or Distiller’s Spent Grain comprising hordeins, in the production of an electrospun fibre.AMENDED SHEET (ARTICLE 19)