GB2454764A

GB2454764A - Separation of biomass fractions

Info

Publication number: GB2454764A
Application number: GB0814312A
Authority: GB
Inventors: Roy Browne
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-08-05
Filing date: 2008-08-05
Publication date: 2009-05-20
Also published as: GB0814312D0

Abstract

A method for processing biomass in order to separate two or more components comprises adding an alcohol solution to the biomass to cause separation into two or more fractions, each comprising at least one of the components of the biomass. The components to be separated preferably comprise starch and protein but may also comprise amino acids, fermentable sugars, low molecular weight metabolites, and cellulose. Typically, the biomass is derived from a plant foodstuff, such as potatoes, cereal crops, maize, wheat, root vegetables, rice, and beans. The method may also comprise adding an enzyme and/or an acid to the biomass. One or more water-washing steps may also be included. A kit containing an alcohol solution and appropriate instructions for fractionating a plant material or isolating starch therefrom is also disdosed.

Description

METHOD FOR THE SEPARATION AND EXTRACTION OF

COMPONENTS FROM BIOMASS

Field of the Invention

The present invention relates to a method for separating and extracting the components of biomass in order to provide raw materials, in particular raw materials suitable for processing for the food and green chemistry industries. More particularly but not exclusively, the invention relates to a method for obtaining starch from potatoes and potato derived material.

Background to the Invention

There is a growing focus on the efficient use of biomass such as plants and crops. For example, a worldwide increase in the demand for food and an increasing interest in the use of biomass in green chemistry processes, such as the production of bio-fuels, have resulted in a growing concern that current bio-fuels such as bio-ethanol largely utilise biomass which could otherwise be used as food stuffs. It would therefore be preferable if the production of bio-fuels could be carried out using low value plant biomass that is not suitable for use as food stuffs rather than using crops, such as wheat and maize, which represent valuable food stuffs. This would increase the amount of food and bio-fuel available by improving the efficiency of the use of biomass, and in particular the efficiency of the use of plant biomass which is currently categorised as low value waste.

One example of plant biomass which is currently categorised as low value waste is potatoes which are not suitable for use in the market for which they are grown. Specifically, potatoes have a wide variety of end uses and the use of specialised varieties of potatoes for specific end uses is common. For example, low sugar potatoes are typically required for use in the manufacture of crisps (potato chips). Similarly, specialised varieties of potatoes are grown for the extraction of starch. However, 5 to 20 % of a potato crop is typically unsuitable for the use for which it is grown. This unsuitability can be due to a number of factors, such as incorrect size, skin damage and/or the deterioration which occurs during packaging and/or storage. Due to the specialised nature of specific potato varieties for specific uses it may be difficult to find another suitable use for the specific potato variety in question. As such, these potatoes are largely redundant and consigned to low value uses, for example, animal feed.

Generally, potato peelings from the processing of potatoes are also categorised as low value waste and therefore typically also used for low value uses, such as animal feed. In some instances, waste potatoes and waste potato products can be used in the production of bio-ethanol.

However, this is practiced on a relatively small scale. A typical method for the production of bio-ethanol involves the steps of mashing the potatoes, adding amylase enzymes, cooking the potatoes and adding further amylase enzymes along with yeast, which under anaerobic conditions results in fermentation and, in turn, alcohol production. However, there are limitations on the overall cost effectiveness of this process.

These waste potatoes and waste potato products represent a large untapped source of useful raw materials, which may have high value uses in the food and green chemistry industries. In particular, waste potatoes and potato peelings represent a large untapped source of starch. Starch is used in numerous food and industrial applications. It is the major form of carbon reserve in plants, constituting 50% or more of the dry weight of many storage organs such as tubers of plants like the potato plant and the seeds of cereals. It can also be derived from root vegetables. Starch is a polysaccharide carbohydrate consisting of glucose monosaccharide units joined by glycosidic bonds. It is predominantly present as amylose, a linear polymer of al -4 linked glucose units, and amylopectin (starch and pectin), a branched polymer consisting of an al -4 linked glucan backbone with al-6 linked branches. Pectin is a jelly like matrix which helps hold cells together. Pectinase enzymes are a mixture of enzymes that catalyse the transformation of pectin into sugars and galacturonic acid. They are widely used in the fruit juice industry to increase juice yield.

Existing methods for starch production utilise varieties of potato which are specifically developed and grown for that purpose. During the starch extraction process, these potatoes are typically pulped and a series of cyclones is then used to separate the starch from the other components.

However, this process requires potatoes specifically grown for starch extraction and the use of cyclones in the extraction of starch is expensive.

Furthermore, as discussed above, a percentage of the potato crop is typically unsuitable for the purpose for which they were grown. It would therefore be beneficial to provide a process for the extraction of starch which could be used with all types of potatoes and potato waste products, such as potato peelings, and/or does not require the use of cyclones.

An alternative method for the extraction of starch from potatoes involves extraction of starch during crisp (potato chip) production. In this production process, the potatoes are washed following cutting in order to remove excess sugars. This washing step is necessary as excess sugars result in excess darkening of the crisps during the subsequent frying stage. The solution from the washing step contains starch. Starch recovery may be performed on this solution with the use of cyclones.

However, the starch from this process has a high moisture content and contains flecks of non-starch potato residue. Typical markets for this low quality starch product are glue manufacturers or relatively low value animal feed.

As such, waste potato products, such as discarded potatoes which are unsuitable for the purpose for which they were grown, potato peelings and low quality starch recovered from processes such as crisp manufacture, represent a largely untapped source of raw materials for the food and green chemistry industries.

Having recognised the need for more efficient ways of using low value plant biomass such as waste potato products, the inventor has surprisingly identified an improved method for the treatment of biomass in order to separate the biomass into specific components for subsequent processing.

Summary of the Invention

According to a first aspect of the present invention there is provided a method for processing biom ass in order to separate two or more components of the biomass into fractions, the method comprising the step of: -adding an alcohol solution to the biomass wherein addition of the alcohol solution results in fractionation of the biomass into two or more fractions, each of the two or more fractions comprising at least one of the components of the biomass.

The inventor has surprisingly identified that the use of the alcohol solution enhances the separation of the components of the biomass into fractions as the addition of the alcohol solution results in a specific sedimentation pattern of the components of the biomass. The enhanced separation of the components of the biomass into specific fractions allows for more efficient subsequent processing of the components for various uses, such as in the food or green chemistry industries. For example, in the case of processes which require that the component of interest undergoes a subsequent enzyme treatment step, the amount of enzymes required for the treatment step is reduced if the component of interest is separated from the other components of the biomass before treatment with the enzymes. Thus, the commercial utility of biomass products that may otherwise be considered waste, or consigned to low value uses such as animal feed, is increased as the purity of the various components may be increased and the cost of subsequent processing reduced.

In certain embodiments, the fractionation of the biomass into the two or more fractions occurs by sedimentation or settling of at least one component and non-sedimentation of at least one other component. The term "non-sedimentation" is used herein to refer to the component remaining in suspension and/or forming one or more top layers.

Without wishing to be bound by theory, it is hypothesised that the enhanced separation of the components of the biomass in the alcohol solution is due to the surprising difference in the buoyancy and/or rate of sedimentation of the various components of the biomass which is observed in the alcohol solution. In particular, it has been observed that starch components settle whereas non-starch components such as low molecular weight metabolites form a top layer.

In certain embodiments, the two or more components to be separated comprise at least one of starch, proteins, amino acids, fermentable sugars, low molecular weight metabolites, cellulose and other non-starch components. In certain embodiments, at least one of the two or more components to be separated is starch.

In certain embodiments, at least one of the fractions comprises the starch component and a further fraction comprises at least one of the components selected from the group consisting of, but not limited to, proteins, low molecular weight metabolites, fermentable sugars, amino acids and other non-starch contaminants, or mixtures thereof.

In certain embodiments, fractionation of the biomass into the two or more fractions occurs by sedimentation of the starch component and non-sedimentation of the components comprising non-starch contaminants. In this way, the alcohol solution allows separation of the starch component of the biomass from the non-starch components.

In certain embodiments, the alcohol solution is also used to denature residual proteins present in the biomass. In certain embodiments, the alcohol solution is used to separate soluble low molecular weight metabolites from the starch component.

The strength of the alcohol solution can be adjusted commensurate to the amount of the alcohol solution which is to be added to the biomass and the amount and/or type of the biomass to be treated. In certain embodiments, the strength of the alcohol solution can be adjusted to ensure that sufficient alcohol is provided to extract low molecular weight metabolites and/or denature the proteins present. Typically the alcohol solution contains alcohol at a percentage by volume which allows the efficient separation of the starch product from proteins in the biomass. In certain embodiments, a 30% to 50% alcohol water solution is used. In certain embodiments, a 40% alcohol water solution is used. In certain embodiments, a range of % alcohol solutions can be used at different stages during the method.

In certain embodiments, the step of adding the alcohol solution is repeated two or more times. This increases the efficiency of the separation of the two more components allowing, for example, pure starch to be separated out. In certain embodiments, the addition of the alcohol solution may be in the form of an alcohol wash. In certain embodiments, the alcohol solution is decanted and, optionally, recycled for use in subsequent treatment steps.

In certain embodiments, the alcohol solution is selected from the group consisting of, but not limited to, primary alcohols, secondary alcohols and tertiary alcohols.

In certain embodiments, the biomass is any material which comprises two or more components wherein it is desirable to separate these components for subsequent processing or other uses. In certain embodiments, the biomass is derived from a plant foodstuff, for example a plant foodstuff which contains at least one of starch, amino acids and proteins. In certain embodiments, the plant foodstuff contains starch and proteins. In certain embodiments, the plant foodstuff contains starch. The plant foodstuff may typically be selected from the group consisting of, but not limited to, potatoes, cereal crops, wheat, maize, root vegetables, rice and beans.

In certain embodiments, the biomass is derived from potatoes.

Advantageously, the potatoes from which the biomass is derived may be any variety of potatoes.

Typically the potato derived biomass is selected from the group consisting of, but not limited to, (i) material derived from a potato wherein the potato was grown for a specific purpose, such as the supply of a particular industry, but the potato was deemed to be unsuitable for use in that industry, for example due to size, shape, colour or freshness of the potato, (ii) material which was left over following use of a potato, for example, potato peelings or the like or material derived from production processes, for example, the manufacture of potato chips, and (iii) material obtained from a solution which is used in a potato processing process, said solution being used, for example, as a washing solution. In certain embodiments, said solution contains a starch product derived from a potato product which is being washed. In certain embodiments, the starch product further contains non-starch contaminants which may also have been derived from the potato product.

In certain embodiments, the method further includes one or more additional steps to enhance breakdown of the biomass into the two or more components, for example, starch, proteins, amino acids, fermentable sugars, low molecular weight metabolites and non-starch components.

Any suitable technique known to persons skilled in the art may be used to breakdown the biomass into the two or more components.

The enhanced breakdown of the biomass into its components increases the efficiency of the fractionation and separation of the components which occurs upon addition of the alcohol solution. Thus, increased purity and/or yield of the two or more components to be separated may be achieved.

In certain embodiments, the method includes a further step of adding an effective amount of at least one enzyme to the biomass. In certain embodiments, the at least one enzyme is any enzyme that assists in the breakdown of the biomass into its components. In certain embodiments, an effective amount of the at least one enzyme is any amount that assists in the breakdown of the biomass into its components.

In certain embodiments, the at least one enzyme is a pectinase enzyme.

In certain embodiments, the at least one enzyme comprises a complex of pectin degrading enzymes.

Without wishing to be bound by theory, the inventor has surprisingly identified that pectinase enzymes are highly effective in methods for recovering solid constituents, such as clean starch, from biomass, in particular potato derived material. In particular, the inventor has surprisingly observed that the use of pectinase enzymes provides for an increase in the efficiency of the separation of a clean starch component from fractions comprising non-starch components.

In certain embodiments, the at least one pectinase enzyme may be any one of the group selected from, but not limited to, polygalacturonase, pectin methyl esterase and pectin lyases, or mixtures thereof.

In certain embodiments, the at least one enzyme is a cellulase enzyme.

In certain embodiments, the step of adding an effective amount of at least one enzyme is repeated one or more times.

This serves to further breakdown the individual components for enhanced separation.

In certain embodiments, the at least one enzyme is provided within a solution to form an enzyme solution. The amount of the enzyme solution and the length of time of exposing the biomass to the enzyme solution can be varied and will depend on the source and/or amount of the biomass and the desired purity and/or yield of the two or more components to be separated. Typically, the length of time which the biomass is exposed to the enzyme solution is sufficient to allow for the breakdown of the biomass into the two or more components.

In certain embodiments, the alcohol solution is added prior to addition of the at least one enzyme, this being followed by one or more further steps of adding the alcohol solution. In certain embodiments, the alcohol solution is added following addition of the at least one enzyme.

In certain embodiments, the method includes a step of adding a suitable amount of at least one acid to the biomass.

In certain embodiments, the acid causes denaturation of proteins present within the biomass. In certain embodiments, the acid is added in an amount suitable for causing denaturation of proteins present within the biomass. In certain embodiments, the acid is any acid which is suitable for causing denaturation of proteins present within the biomass. In certain embodiments, the acid is selected from the group consisting of acetic acid, ascorbic acid (vitamin C), citric acid, organic acids, inorganic acids and the like. In certain embodiments, the acid is citric acid. In certain embodiments, the acid is acetic acid.

In certain embodiments, the at least one acid serves to reduce or prevent oxidation and/or discolouration of the biomass. In certain embodiments, the at least one acid is added in an amount suitable for reducing oxidation and/or discolouration of the biomass. In certain embodiments, the at least one acid is any acid which is suitable for reducing oxidation and/or discolouration of the biomass. In certain embodiments, the at least one acid is selected from the group consisting of acetic acid, ascorbic acid (vitamin C), citric acid, organic acids, inorganic acids and the like. In certain embodiments, the at least one acid is ascorbic acid.

In certain embodiments, the at least one acid which reduces oxidation and/or discolouration of the biomass is the same acid as the acid which is used to denature the proteins present in the biological material. In certain embodiments, a combination of one or more acids is used. In certain embodiments, a first acid is used to reduce oxidation and/or discolouration of the biomass and a second acid is used to denature the proteins present in the biomass. In certain embodiments, the acid for reducing oxidation and/or discolouration of the biomass is added at a stage separate to the addition of the acid to mediate protein denaturisation.

In certain embodiments, the at least one acid is added before the addition of the at least one enzyme. In alternative embodiments, the at least one acid is added after addition of the at least one enzyme. In yet further alternative embodiments, the at least one acid is added at the same time as the at least one enzyme.

The addition of the at least one acid before or at the same time as the addition of the at least one enzyme is advantageous as the acidic (low pH) environment enhances the activity of the at least one enzyme.

In certain embodiments, the step of adding the at least one acid may be repeated two or more times.

The amount of the at least one acid and the length of time of the exposure of the at least one acid to the biomass can be varied and will depend on the source and/or amount of the biomass and the desired purity and/or yield of the components to be separated. Typically, the length of time which the biomass is exposed to the at least one acid is sufficient to denature the proteins present in the biomass and/or reduce oxidation of the biomass.

In certain embodiments wherein the biomass is derived from the plant foodstuff, the method includes one of more steps of deriving the biomass from the plant foodstuff, such as potatoes. For example, in certain embodiments, the method includes a step of treating the plant foodstuff to form a pulp. The term "pulp" is used herein to refer to a form of the biomass wherein the size of the plant foodstuff has been reduced such that the surface area of the plant foodstuff is increased. In certain embodiments, the treatment which is used is a technique such as pulping, grinding, cutting, a mixture thereof or any other suitable technique.

In certain embodiments, following the treatment of the plant foodstuff to form a pulp, the method includes a subsequent step of separating the pulped plant foodstuff into a liquid fraction and a cellulose-rich pulp fraction. This separation step may be performed using any suitable separation process, suitable processes being known to the person skilled in the art. In certain embodiments, the separation is performed using at least one sieve in combination with centrifugal force. Typically, the liquid fraction remaining following separation of the cellulose-rich pulp fraction from the pulped plant food stuff comprises starch, protein and sugar components.

In certain embodiments, the liquid fraction is subjected to a further treatment step prior to the addition of the alcohol solution. Typically, the liquid fraction is separated into a starch-rich fraction, which is in the form of a solid/slurry, and a protein-rich liquid fraction comprising proteins, amino acids and sugars. Typically, the starch-rich fraction comprises starch, residual proteins, low molecular weight metabolites and other non-starch contaminants.

In certain embodiments, the alcohol solution is added to this starch-rich fraction to separate the starch component from the non-starch components. Typically, this separation step is performed through the sedimentation of the starch component in the starch-rich fraction.

Typically, sedimentation results in a bottom fraction of soil/grit, a middle fraction comprising the starch component and a top fraction comprising non-starch components. In certain embodiments, the top fraction is removed and subjected to further separation steps.

The addition of the alcohol solution to the starch-rich fraction surprisingly enhances separation of the starch component of the starch-rich fraction from the non-starch components. Thus, the purity and yield of the starch component is increased.

The step of subjecting the liquid fraction to one or more additional treatment steps prior to the addition of the alcohol solution advantageously reduces the amount and/or strength of the alcohol solution which is required for treatment of the biomass to separate the components.

In certain embodiments, one or more washing steps may be performed between at least some of the aforementioned steps. The one or more intermediate washing step may typically be a wash which uses a water solution. In certain embodiments, a combined water and alcohol wash solution may be used.

In certain embodiments, the method further comprises the step of extracting a protein or amino acid mixture from the protein-rich liquid fraction, which is derived following settlement (sedimentation) of the starch-rich fraction.

The inventor has identified that the extraction of the protein-rich liquid fraction can be useful as this fraction contains proteins and fermentable sugars, and may also contain a high level of amino acids which are suitable for fermentation. The proteins present within this fraction can be denatured and/or precipitated and separated from this liquid, for example, by centrifugation. The proteins isolated during this purification method may have utility in downstream processes, such as a use as animal feed or in the food industry. Following removal of the proteins, the remaining liquid comprises sugars and amino acids, which may be used in fermentation or in methods for the production of bio-fuel, such as bio-ethanol.

A second aspect of the present invention provides for an improved method for the recovery of components from a potato-derived material, said method comprising the step of: -washing the potato-derived material with an alcohol solution wherein the alcohol solution results in fractionation of the potato-derived material into two or more fractions, each of the two or more fractions comprising at least one of the components of the potato-derived material.

The inventor has surprisingly identified that the use of the alcohol solution enhances the separation of the components of the potato-derived material into the two or more fractions as the addition of the alcohol solution results in a specific sedimentation pattern of the components of the potato-derived material.

In certain embodiments, the fractionation of the potato-derived material into the two or more fractions occurs by sedimentation of at least one component, for example, starch and non-sedimentation of at least one other component, for example, low molecular weight metabolites.

In certain embodiments, the two or more components to be separated comprise at least one of starch, proteins, amino acids, fermentable sugars, low molecular weight metabolites and non-starch components. In certain embodiments, at least one of the two or more components to be separated is starch.

In certain embodiments, fractionation of the potato-derived material into the two or more fractions occurs by sedimentation of the starch component and non-sedimentation of the components comprising non-starch components. In this way, the alcohol solution enhances separation of the starch component from the non-starch components. Typically, the non-starch components may form flecks of material which remain in suspension and/or in the upper most layers following sedimentation of the starch component. In certain embodiments, the upper most layers and/or material from the suspension is recycled for further treatment.

In certain embodiments, the alcohol solution may also be used to denature residual proteins present in the potato-derived material. In certain embodiments, the alcohol solution may be used to separate soluble low molecular weight metabolites from the starch component.

Typically the potato derived material is selected from the group consisting of, but not limited to, (i) material derived from a potato wherein the potato was grown for a specific purpose, such as the supply of a particular industry, but the potato was deemed to be unsuitable for use in that industry, for example due to size, shape, colour or freshness of the potato, (ii) material which was left over following use of a potato, for example, potato peelings or the like or a by-product of a potato-processing industry, for example, the manufacture of potato chips, and (iii) material obtained from a solution which is used in a potato processing process, said solution being used, for example, as a washing solution. In certain embodiments, said solution contains a starch product derived from a potato product which is being washed. In certain embodiments, the starch product may further contain non-starch contaminants which may also be derived from the potato product.

Advantageously, the potatoes from which the material is derived may be any variety of potatoes and are not restricted to a specific variety of potato grown for a specific purpose.

In certain embodiments, the method further comprises one or more additional steps of adding at least one enzyme to the potato-derived material. This results in increased yield and/or purity of the components to be separated.

In certain embodiments, the method further comprises one or more additional steps of adding at least one acid. The addition of the at least one acid reduces oxidation of the biomass and/or causes denaturation of proteins present in the biomass.

Embodiments of the present invention described hereinbefore in relation to the first aspect of the present invention apply, where applicable, mutatis mutandis to the second aspect of the present invention.

A yet further aspect of the present invention provides a purified starch product produced using the foregoing methods of the invention.

A further still aspect of the invention provides for the use of the foregoing methods of the invention for the production of starch.

A yet further aspect of the present invention provides a kit for use in fractionating a plant material, said kit comprising an alcohol solution along with instructions for the use of the same. In certain embodiments, an enzyme solution and/or an acid solution is also included.

A further still aspect of the invention provides a kit for use in isolating starch from plant material, the kit comprising an alcohol solution along with instructions for the use of the same. In certain embodiments, an enzyme solution and/or an acid solution is also included.

Definitions Unless otherwise defined, all technical and scientific terms used herein have the meaning commonly understood by a person who is skilled in the

art in the field of the present invention.

Throughout the specification, unless the context demands otherwise, the terms "comprise" or "include", or variations such as "comprises" or "comprising", "includes" or "including" will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers.

As used herein, terms such as "a", "an" and "the" include singular and plural referents unless the context clearly demands otherwise.

EXMAPLE

Extraction of starch from potatoes Potatoes of the cultivar Rooster variety were used.

In one method, whole potatoes were pulped and lemon juice, containing citric acid and vitamin C, and pectinase enzyme added. The cellulose-rich pulp fraction was separated from the liquid fraction using a juice extractor.

In an alternative method, the potatoes were pulped directly with the lemon juice. The cellulose-rich pulp fraction was separated from the liquid fraction using a juice extractor. Pectinase enzyme was added to the liquid fraction.

The liquid fraction was stirred for 20 minutes and then allowed to settle for at least 20 minutes during which time the starch-rich sediment fraction settled and the material in the liquid suspension was decanted off as supernatant. The decanted material was comprised predominantly of proteins and fermentable sugars and was identified as being rich in amino acids.

Fresh water was added to the starch-rich sediment fraction along with pectinase enzyme. The mixture was then stirred for two hours. Thereafter, the mixture was allowed to settle until the liquid was clear of starch and decanted off.

The remaining starch-rich sediment fraction was then washed in a 40% alcohol water solution for one hour with stirring and allowed to settle. This washing step denatured and extracted the residual proteins that were contained in the remaining starch-rich fraction. The addition of the alcohol solution resulted in sedimentation of the starch component of the starch-rich fraction whilst non-starch contaminants remained in suspension.

These non-starch contaminants comprised white flecks appearing at the top of, and/or in suspension in, the solution. After the solution had been allowed to settle, the supernatant was decanted off.

The preceding two steps of the addition of the pectinase enzyme and the alcohol solution washing step were then repeated on the starch-rich (settled) fraction. Following the treatment, once the starch-rich fraction had settled, the less dense top layer which still contained impurities was removed for further processing. After decanting the final alcohol wash, the starch was dried. The starch was observed to be of a high purity.

The supernatant from the first settling was treated to denature the proteins using heat (>60°C). The denatured proteins were removed through sieving leaving a protein rich solid residue. The liquid filtrate was rich in fermentable amino nitrogen sugars, which were fermented to produce alcohol and carbon dioxide using an anaerobic fermentation with yeast.

Relatively low brix (sugar content) solutions can be adjusted using additional sugars or by concentration of the solution, for example by reverse osmosis.

Claims

Claims 1. A method for processing biornass in order to separate two or more components of the biomass into fractions, the method comprising the step of: -adding an alcohol solution to the biomass wherein addition of the alcohol solution results in fractionation of the biomass into two or more fractions, each of the two or more fractions comprising at least one of the components of the biomass.
2. A method as claimed in claim 1 wherein the fractionation of the biomass into the two or more fractions occurs by sedimentation of at least one of the two or more components of the biomass.
3. A method as claimed in claim 1 or 2 wherein the two or more components to be separated comprise at least one of starch, proteins, amino acids, fermentable sugars, low molecular weight metabolites, cellulose and other non-starch components
4. A method as claimed in claim 3 wherein at least one of the two or more components to be separated is starch.
5. A method as claimed in any preceding claim wherein at least one of the fractions comprises a starch component and a further fraction comprises at least one of the components selected from the group consisting of proteins, low molecular weight metabolites, fermentable sugars, amino acids and other non-starch components, or mixtures thereof.
6. A method as claimed in any preceding claim wherein the fractionation of the biomass into the two or more fractions occurs by sedimentation of a starch component and non-sedimentation of at least one non-starch component.
7. A method as claimed in any preceding claim wherein the alcohol solution is used to denature proteins present in the biomass.
8. A method as claimed in any preceding claim wherein the alcohol solution is used to separate soluble low molecular weight metabolites from a starch component.
9. A method as claimed in any preceding claim wherein the biomass is derived from a plant foodstuff.
10. A method as claimed in claim 9 wherein the plant foodstuff is selected from the group consisting of potatoes, cereal crops, maize, wheat, root vegetables, rice and beans.
11. A method as claimed in claim 10 wherein the plant foodstuff is potatoes.
12. A method as claimed in any preceding claim wherein the method includes a step of adding an effective amount of at least one enzyme to the biomass.
13. A method as claimed in claim 12 wherein the at least one enzyme comprises a pectinase enzyme or a mixture of pectinase enzymes.
14. A method as claimed in claim 12 wherein the at least one enzyme comprises a cellulase enzyme.
15. A method as claimed in any preceding claim wherein the method includes a step of adding at least one acid to the biomass.
16. A method as claimed in claim 15 wherein the at least one acid causes denaturation of proteins present within the biomass.
17. A method as claimed in claim 15 or 16 wherein the at least one acid reduces oxidation of the biomass.
18. A method as claimed in any one of claims 15 to 17 wherein the at least one acid is selected from the group consisting of citric acid, ascorbic acid, acetic acid, organic acids and inorganic acids, or mixtures thereof.
19. A method as claimed in any one of claims 15 to 18 wherein a mixture of acids is used.
20. A method as claimed in any one of claims 9 to 19 wherein the method includes a step of deriving the biomass from the plant foodstuff.
21. A method as claimed in claim 20 wherein the step of deriving the biomass from the plant foodstuff comprises treating the plant foodstuff to form a pulp.
22. A method as claimed in claim 21 wherein the method comprises a further step of separating the pulped plant foodstuff into a liquid fraction and a cellulose-rich pulp fraction.
23. A method as claimed in claim 22 wherein the method comprises a further step of separating the liquid fraction into a starch-rich fraction and a protein-rich liquid fraction.
24. A method as claimed in claim 23 wherein the alcohol solution is added to the starch-rich fraction.
25. A method as claimed in any preceding claim including one of more washing steps with water.
26. A method as claimed in any preceding claim wherein at least one of the steps of adding the alcohol solution, adding the at least one enzyme and adding the at least one acid is repeated one or more times.
27. A method as claimed in claim 23 wherein the protein-rich liquid fraction is subjected to one or more purification steps.
28. An amino acid mixture produced by the method of claim 27.
29. A starch product produced by the method of any one of claims 1 to 26.
30. A method for the recovery of components from a potato-derived material, said method comprising the step of: -washing the potato-derived material with an alcohol solution wherein the alcohol solution results in fractionation of the potato-derived material into two or more fractions, each of the two or more fractions comprising at least one of the components of the potato-derived material.
31. A method as claimed in claim 30 wherein the fractionation of the potato-derived material into the two or more fractions occurs by sedimentation of at least a starch component and non-sedimentation of at least one non-starch component.
32. A method as claimed in claim 31 wherein the non-starch component comprises at least one of proteins, amino acids, fermentable sugars, low molecular weight metabolites and cellulose.
33. A method as claimed in any one of claims 30 to 32 wherein the potato derived material comprises at least one of the group consisting of potato peelings, potato products derived from a manufacturing process, potato products derived from a washing solution used during the manufacture of a potato product and material derived from waste potatoes which were unsuitable for the purpose for which they were grown.
34. A method as claimed in any one of claims 30 to 33 wherein the method includes a step of adding at least one enzyme to the potato-derived material.
35. A method as claimed in any one of claims 30 to 34 wherein the method includes a step of adding at least one acid to the potato-derived material.
36. A method as claimed in any one of claims 30 to 35 including one of more washing steps with water.
37. A method as claimed in any one of claims 30 to 36 wherein at least one of the steps of washing with the alcohol solution, adding the at least one enzyme and adding the at least one acid is repeated one or more times.
38. A purified starch product produced using the methods of any one of claims 30 to 37.
39. The use of the methods as claimed in any one of claims 1 to 26 and to 37 for the production of starch.
40. A kit for use in fractionating a plant material, said kit comprising an alcohol solution along with instructions for the use of the same.
41. A kit for use in isolating starch from plant material, the kit comprising an alcohol solution along with instructions for the use of the same.
42. A method substantially as hereinbefore described with reference to the accompanying example.