Extraction process and apparatus

Abstract

The present invention relates to processes for isolating plant proteins, and products of the processes including a plant juice that can be used for processing to produce plant proteins. The present invention also relates to processes for producing a plant juice comprising protein from plant material. The process comprises steps of extracting plant juice from the harvested plant material; cooling the extracted plant juice; and recirculating a portion of the cooled extracted plant juice into the extraction step. The plant juice is capable of further processing to produce protein containing products, including Rubisco as a powder. The present invention also relates to a juicing apparatus for removing liquid from a harvested crop of plant material in a field.

Description

EXTRACTION PROCESS AND APPARATUS FIELD OF THE INVENTION

[0001] This application claims priority to Australian Provisional Application No. 2022903991 filed 22 December 2022 and Australian Provisional Application No. 2022903987 filed 22 December 2022, the contents of each of which are herein incorporated by reference.

[0002] The present invention broadly relates to processes for isolating plant proteins, and products of the processes including a plant juice that can be used for processing to produce plant proteins. The present invention also broadly relates to processes for producing a plant juice comprising protein from plant material. The plant juice is capable of further processing to produce protein containing products, including Rubisco as a powder. The present invention also broadly relates to a juicing apparatus for removing liquid from a harvested crop of plant material in a field. BACKGROUND TO THE INVENTION

[0003] Ribulose-1,5-biphosphate carboxylase / oxygenase, known as RuBisCo or Rubisco, is the most abundant protein in the world, being present in all green leaves. Rubisco plays a critical role as the first enzyme involved in fixation of atmospheric carbon dioxide into energy rich molecules during photosynthesis.

[0004] Leaf protein was identified as a food source in the 1940s by British biochemist and virologist Norman Pirie during the Second World War. In the 1950s this protein fraction was characterized as being principally comprised of Rubisco, a white, cytoplasmic protein with a large molecular weight by Wildman et al. In the 1970s researchers at the USDA Western Regional Research Centre undertook studies to extract Rubisco as a leaf protein concentrate from alfalfa in a process they called “Pro- Xan”. Other studies focussed on Rubisco, to increases its efficiency for carbon capture / biomass accumulation, crop yield, and seed yield. Rubisco makes up about 30-50% of the soluble protein in plant leaf (Erb TJ, Zarzycki J. A short history of RubisCO: the rise and fall (?) of Nature's predominant CO2fixing enzyme. Curr Opin Biotechnol. 2018 Feb;49:100-107).

[0005] In nutritional terms, Rubisco has a complete amino acid profile, and is reported to have a digestibility score comparable to beef proteins (PDCAAS score). When isolated in its pure form, it has a neutral flavour and off-white colour. It is a very versatile food ingredient, with high foam stability, high solubility, and good gelling and emulsion properties.

[0006] A general process for plant protein is the pressing of biomass to form a pulp and a green juice, and filtration of “green” plant proteins from the juice to form green protein solids and a brown juice, and refining and purification of the brown juice to form a white plant protein (Nynäs, Introductory paper at the Faculty of Landscape Architecture, Horticulture and Crop Production Science, 2018). The plant biomass most preferred for this process are green leaves, which have a high plant protein and Rubisco content.

[0007] Sources of Rubisco protein are the photosynthetic organelles, such as those present in plants and plant waste material, which are typically cut or harvested and then transported to a processing facility for protein extraction. Transport of the bulk plant material requires significant resources and also typically requires additional steps for preservation of the bulk plant material until it can be processed, including applying reducing agents to the bulk plant material and / or refrigerating it while it is being shipped, to slow down enzymatic processes triggered by plant death. These steps represent significant cost and difficulty.

[0008] Isolation of Rubisco in its native form is difficult as the protein subunits are prone to disassociation, denaturation, and precipitation. Providing a product comprising Rubisco protein isolate for human consumption provides further challenges in terms of scale-up for industrial methods, complicated processing steps for removal of impurities, food safety, including microbiological food safety, yield, and product purity.

[0009] It is desirable to provide processes that result in commercially attractive levels of protein, including Rubisco, in products produced from plant material.

[0010] Apparatus for processing plant materials for protein extraction are complex and require many components in order to process the harvested plant material into a final product, and can be uneconomic and impractical to manufacture and use.

[0011] It is desirable to extract a plant protein product as a plant juice in a form that maximises the protein content of Rubisco available for processing into other protein containing products.

[0012] It is also desirable to provide a plant juice extracted from a plant material that maximises the protein content of Rubisco available for processing to isolate Rubisco as a product free of components that may be associated with bitter, astringent, or metallic flavours, and may introduce non- white colours such as green or brown.

[0013] It is an object of the present invention to go at least some way to addressing one or more of the above and / or to at least provide the public with a useful choice.

[0014] Other objects of the invention may become apparent from the following description which is given by way of example only.

[0015] Any discussion of documents, acts, materials, devices, articles, or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date. SUMMARY OF THE INVENTION

[0016] In a first aspect, the invention provides a process for producing a plant juice comprising protein from a harvested plant material, the process comprising steps of: a) extracting plant juice from the harvested plant material; b) cooling the extracted plant juice; c) recirculating a portion of the cooled extracted plant juice from step (b) into the extraction step (a); and d) adding a dosing composition to the extracted plant juice to produce the plant juice comprising protein.

[0017] In another aspect, the invention provides a process for producing a plant juice comprising a protein content of between about 5-50% on a dry weight basis from a harvested plant material, the process comprising steps of: a) harvesting the plant material as a whole plant; b) passing the plant material of step (a) through a screw press to extract plant juice from the harvested plant material; c) cooling the extracted plant juice to a temperature of below about 12°C;d) recirculating a portion of the cooled extracted plant juice from step (c) into the screw press with plant material; and e) adding sodium metabisulfite to the cooled extracted plant juice after steps (c) and (d) to produce the plant juice; and wherein the temperature in the screw press in step (b) is controlled so that the temperature of the extracted plant juice from step (b) is below about 20ºC via the recirculation in step (d), and wherein the time between passing the plant material through the screw press in step (b) and commencing cooling of the extracted plant juice in step (c) is between about 3 and about 15 minutes.

[0018] In another aspect, the invention provides a plant juice extracted from a plant material, wherein the plant juice: a) comprises a protein content of between about 5-50% on a dry weight basis, b) has a temperature of less than about 12°C, and c) is stable for at least 4 hours.

[0019] In another aspect, the invention provides a stable plant juice extracted from a plant material, wherein the plant juice: a) comprises a protein content of between about 5-50% on a dry weight basis, b) has a temperature of below 5°C, c) sodium metabisulfite in an amount of less than 0.03% w / v d) a polyphenolic content of less than about 6% w / w, and e) a microbial load of less than about 600,000cfu / ml after about 4 hours.

[0020] In another aspect, the invention provides an apparatus for producing a plant juice comprising protein from a plant material, the apparatus comprising:(i) a juicer configured to extract from plant material to produce a plant juice, the juicer having an inlet to plant material and a juice outlet for the plant juice that has been extracted from the plant material; (ii) a cooling system configured to cool the juice that has been extracted from the plant material; (iii) a juice recirculation system configured to receive a portion of cooled juice from a location at or near the juice outlet downstream of the cooling system and deliver the portion of cooled juice to the juicer; (iv) optionally a storage tank fluidly connected to the juice outlet, the storage tank being configured to maintain the juice at the cooled temperature; and (v) a dosing mechanism configured to deliver a dosing composition to the juice downstream from the juice outlet.

[0021] In another aspect, the invention provides a process for producing a plant juice from a harvested plant material, the process comprising steps of: • extracting juice from the plant material; • cooling the extracted juice; and • adding a dosing composition to the extracted juice; wherein the time between harvesting and commencing cooling of the extracted juice from the plant material is less than 15 minutes.

[0022] In another aspect, the invention provides a process for producing a cooled plant juice comprising protein from a plant material, the process comprising steps of: • harvesting the plant material at a harvest site; and • extracting juice from the plant material in an extraction step; • cooling the extracted juice; • recirculating a portion of the cooled juice to the extraction step; • adding a dosing composition to the extracted juice; andwherein the time between harvesting and cooling of the extracted juice from the plant material is less than 15

[0023] In another aspect, the invention provides a plant juice having a low microbial load and low enzymatic activity, the plant juice being stable for at least 8 hours, more preferably at least 6 hours and more preferably between about 2 to about 6 hours.

[0024] In another aspect, the invention provides a plant juice which has been produced by the process according to any one of the previous process aspects of the invention.

[0025] In another aspect, the invention provides a food product, total protein product, or a white protein product derived from a plant juice produced from a process according to any one of the previous aspects of the invention or the plant juice aspect of the invention.

[0026] In another aspect, the invention provides a plant pulp which has been produced from a process according to any one of aspects of the invention.

[0027] In another aspect, the invention provides an animal feed or silage comprising a plant pulp according to plant pulp aspect of the invention.

[0028] In a further aspect, the invention provides a method of producing a white protein product, comprising: • subjecting a plant juice produced according to one of the process aspects of the invention, or the plant juice aspect of the invention, to a separation step to produce a brown juice and a green protein material; • microfiltration of the brown juice to remove microorganisms, large carbohydrates, and residual cell-wall materials; • ultrafiltration of the brown juice to produce a permeate and a retentate; • concentrating and drying of the retentate to produce a white protein product.

[0029] The following embodiments and preferences may relate alone or in any combination of any two or more to any of the above aspects.

[0030] Preferably, the harvested material has been harvested as a whole plant or part of a plant.

[0031] Preferably, the plant material is selected from any one or more of the family Fabaceae; the family Gramineae; the family Lemnoideae; from the family Brassicaceae; or the family Amaranthaceae.

[0032] Preferably, the plant material comprises leaf material selected from any one or more of alfalfa, kudzu, forage peas, oats, duckweed, spinach, kale, roadside crops, cocksfoot, Italian ryegrass, Raphno® (kale-radish hybrid), clover, Persian clover, rapeseed, carrots, radishes, Jerusalem artichoke, beets, spinach, fodder beet; triticale, white clover, barley, tobacco, chicory, sugar cane, or fava bean.

[0033] Preferably, the harvested plant material has been harvested as a whole plant and wherein the plant has been cut by the harvester between about 7cm and about 20cm above the ground.

[0034] Preferably, the plant juice is extracted from the plant material using at least one maceration device.

[0035] Preferably, the maceration device is selected from any one or more of a screw press; a hydraulic press; a mincer; or a blender.

[0036] Preferably, the maceration device is a screw press or a plurality of screw presses.

[0037] Preferably, the maceration device is a screw press or a plurality of screw presses having between about 1.5T and 20T back pressure, more preferably between 1.5T and 9T back pressure. Preferably, when a plurality of screw presses are used, the back pressures of the screw presses can be the same or different.

[0038] Preferably, the screw press or any one of the plurality of screw presses comprises a twin screw press.

[0039] Preferably the extracted plant juice is cooled in step (b) to a temperature of below about 12°C.

[0040] Preferably, the cooling of the extracted plant juice in step (b) commences within about 5 minutes of extraction.

[0041] Preferably, the portion of the cooled plant juice recirculated in step (c) is taken from the cooled plant juice before dosing composition of step (d) is added.

[0042] Preferably, the portion of the cooled plant juice recirculated in step (c) is added with the harvested plant material as it enters extraction step (a).

[0043] Preferably, the ratio of the cooled plant juice recirculated in step (c) to the harvested plant material in the extraction step (a) is in the range of 2:1 to 1:2 (wt / wt), more preferably the ratio is about 1:1 (wt / wt).

[0044] Preferably, the temperature in step (a) is controlled such that the juice extracted in step (a) is below about 20ºC, more preferably below about 15ºC, using the recirculated portion of the cooled extracted plant juice in step (c).

[0045] Preferably, the plant juice comprising protein produced by the process is stored at a temperature of below about 12ºC, or more preferably less than about 7ºC, or more preferably about 4°C.

[0046] Preferably, the plant juice comprising protein produced by the process is stored in a refrigerated container.

[0047] Preferably, the time between extracting the plant juice from the harvested plant material and commencing cooling the extracted plant juice is between about 15 and about 3 minutes.

[0048] Preferably, the time between harvesting the plant material and commencing cooling the extracted plant juice in step (b) is less than about 3 hours.

[0049] Preferably, the dosing composition comprises any one of more of: a reducing agent, chelating agent, pH modifying agent, mono, divalent or trivalent metal ions, a precipitant, minerals, a filter aid, or a modifying buffer or co-solvent.

[0050] Preferably, the dosing composition comprises a reducing agent selected from ascorbic acid, citric acid, oxalic acid, cysteine, dithiothreitol (DTT), dithioerythritol (DTE), tris(2-carboxyethyl)phosphine (TCEP), β-mercaptoethanol (BME), sodium dithionate, nitrilotriacetic acid (NTA), Cysteamine, Glutathione (GSH) and / or metabisulfite.

[0051] Preferably, the dosing composition comprises aqueous sodium metabisulfite.

[0052] Preferably, the dosing is added in an amount of dosing agent sufficient to result in a concentration of dosing agent in the plant juice comprising protein of from about 0.005% to 2.0% (w / v) or from about 0.005% to 0.03% (w / v), more preferably from about 0.005% to about 0.03%(w / v).

[0053] Preferably, the dosing composition is added in an amount sufficient to result in a concentration of the dosing composition in the plant juice comprising protein produced by the process of less than 0.03% (w / v).

[0054] Preferably, the dosing composition is added as a fixed dose to the extracted plant juice in step d).

[0055] Preferably, the plant juice comprises protein of which at least 10% by weight of total protein is Rubisco. Even more preferably, the plant juice comprises protein of which at least 40% by weight of total protein is Rubisco.

[0056] Preferably, the plant juice comprising protein produced by the process is stored and comprises: a) a protein content of between about 5-50% on a dry weight basis, b) a temperature of less than about 12°C, and wherein the plant juice is stable for at least 4 hours.

[0057] Preferably, the plant juice comprising protein comprises a protein content of between about 10-35% on a dry weight basis, and a total carbohydrate content of between about 15-40% on a dry weight basis.

[0058] Preferably, the process further comprising a step of transporting the juice to a processing facility.

[0059] Preferably, the plant juice produced according to the invention and cooled to about 4°C has a microbial load of less than about 1,000,000 cfu / mL after about 9 hours, measured by aerobic plate count. More preferably, the plant juice produced according to the invention and cooled to about 4°C has a microbial load of less than about 600,000 cfu / mL after about 4 hours and less than about 1,000,000 cfu / mL after about 9 hours, measured by aerobic plate count.

[0060] Preferably, the plant juice produced according to the invention and maintained at less than about 4°C for up to 24 hours can be prepared, which whenprocessed can be used to prepare protein products which are acceptable from regulatory perspective with a low

[0061] Preferably, the plant juice comprises a protein content of between about 10-35% on a dry weight basis, and a total carbohydrate content of between 15-40% on a dry weight basis.

[0062] Preferably, the plant juice comprises a sodium metabisulfite in an amount of between about 0.005% to 2.0% (w / v).

[0063] Preferably, the plant juice comprises a polyphenolic content of less than about 6%.

[0064] Preferably, the plant juice has a temperature of about 4°C, and the plant juice has a microbial load of less than about 1,000,000 cfu measured by aerobic plate count after about 9 hours.

[0065] Preferably, the plant juice has a temperature of about 4°C, and a microbial load of less than about 600,000cfu / ml after about 4 hours.

[0066] Preferably, the juicer is selected from any one or more of a screw press, a hydraulic press, a mincer, or a blender.

[0067] Preferably, the cooling system comprises a heat exchanger.

[0068] Preferably, the cooling system comprises a plate heat exchanger.

[0069] Preferably, the cooling system comprises a refrigeration system that comprises a refrigeration conduit in fluid communication with the storage tank and the heat exchanger.

[0070] Preferably, the refrigeration system comprises a pump configured to move the juice in the refrigeration conduit from the storage tank towards the heat exchanger.

[0071] Preferably, the cooling system commences cooling the plant juice within about 5 minutes of extraction from the plant material.

[0072] Preferably, the cooling system cools the plant juice to a temperature of less than about 12ºC.

[0073] Preferably, the juice recirculation system receives a portion of cooled juice from upstream of the dosing mechanism to the juicer.

[0074] Preferably, the juice recirculation system is configured to deliver a portion of the cooled juice to the inlet of the

[0075] Preferably, the apparatus comprises a storage tank fluidly connected to the juice outlet and a dosing composition inlet connected to the storage tank, and wherein the storage tank comprises an agitation device configured to mix the dosing composition with the plant juice.

[0076] Preferably, the apparatus comprises a storage tank fluidly connected to the juice outlet, the storage tank being capable to maintain the temperature of the plant juice in the storage tank at a temperature of less than about 12ºC.

[0077] Preferably, the time between harvesting and commencing cooling of the extracted juice from the plant material is less than about 7, or more preferably less than about 5 minutes.

[0078] Preferably, the extracted juice is cooled to less than about 12ºC or more preferably less than about 7ºC. More preferably, the extracted juice is cooled to about 4°C.

[0079] Preferably, the dosing composition is added to the juice after cooling the juice.

[0080] Preferably, the dosing composition comprises metabisulfite.

[0081] Preferably, the process further comprising a step of transporting the juice to a processing facility.

[0082] Preferably, the process of the invention does not include a step of hydrophobic column absorption.

[0083] The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

[0084] It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates reference to all rational numbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9, and 10) and also any range ofrational numbers within that range (for 2 to 8, 1.5 to 5.5, and 3.1 to 4.7) and, therefore, all sub-ranges of all ranges disclosed herein are hereby expressly disclosed. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner.

[0085] In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

[0086] To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

[0087] Although the present invention is broadly as defined above, those persons skilled in the art will appreciate that the invention is not limited thereto and that the invention also includes embodiments of which the following description gives examples. DEFINITIONS

[0088] The following definitions are presented to better define the present invention and as a guide for those of ordinary skill in the art in the practice of the present invention. Unless otherwise specified, all technical and scientific terms used herein are to be understood as having the same meanings as is understood by one of ordinary skill in the relevant art to which this disclosure pertains.

[0089] The general chemical and biological terms used herein have their usual meanings.

[0090] Examples of definitions of common terms in microbiology, molecular biology and biochemistry can be found in Methods for General and Molecular Microbiology, 3rdEdition, C. A. Reddy, et al. (eds.), ASM Press, (2008); Encyclopedia of Microbiology, 2nd ed., Joshua Lederburg, (ed.). Academic Press, (2000); Microbiology ByCliffs Notes, I. Edward Alcamo, Wiley, (1996); Dictionary of Microbiology and Molecular Biology, Singleton et al. (2d ed.) (1994); of Microorganisms 11t h ed. Brock et al., Pearson Prentice Hall, (2006); Biodiversity of Fungi: Inventory and Monitoring Methods, Mueller et al. Academic Press, (2004); Genes IX, Benjamin Lewin, Jones & Bartlett Publishing, (2007); The Encyclopedia of Molecular Biology, Kendrew et al. (eds.), Blackwell Science Ltd., (1994); and Molecular Biology and Biotechnology: a Comprehensive Desk Reference, Robert A. Meyers (ed.), VCH Publishers, Inc., (1995).

[0091] The term “comprising” as used in this specification and claims means “consisting at least in part of”. When interpreting each statement in this specification and claims that includes the term “comprising”, features other than that or those prefaced by the term may also be present. Related terms such as “comprise”, “comprised” and “comprises” are to be interpreted in the same manner.

[0092] As used herein the term “and / or” means “and” or “or”, or both.

[0093] As used herein “(s)” or “(es)” following a noun means the plural and / or singular forms of the noun.

[0094] The term “plant juice” as used herein refers to the juice obtained by extracting a plant material. The plant juice contains small plant fragments such as cell wall, cellulosic materials, membrane associated proteins, soluble cytosolic proteins, carbohydrates, minerals, lipids, plant secondary metabolites such as saponins and flavonoids, peptides, organic molecules, water, and other components. Since it contains chlorophyll it is often termed “green juice”.

[0095] The “soluble cytosolic proteins” described in the “plant juice” means the soluble liquid phase proteins from the cytoplasm, produced by juicing the plant, for example, principally Rubisco, the most abundant protein within the cytoplasmic fraction, but also associated soluble proteins such as glutamate synthase, transketolase, glycine dehydrogenase, cobalamin-independent methionine synthase, serine hydroxymethyltransferase, and ferredoxin-NADP reductase (by way of non-limiting examples.)

[0096] The term “brown juice” as used herein refers to the brown supernatant (alternatively called permeate) which is obtained by separating the green proteins from the plant juice in the separation step discussed herein.

[0097] The terms “green proteins” and “green protein fraction” as used herein refer to the components of the plant juice comprising chlorophyll and chlorophyll-containing proteins, large carbohydrates, residual cell-wall material, and membrane fragments. The term “green protein is used to refer to a solid or semisolid form of green proteins. The term “white proteins” and “white protein fraction” as used herein refer to the soluble plant proteins including Rubisco.

[0098] The term “total protein” as used refers to protein calculated by measuring total nitrogen and non-protein nitrogen separately using Kjeldahl method to calculate the total protein nitrogen. This total protein nitrogen is then multiplied by a constant (6.25) to calculate total protein. Total protein includes protein and will not include any non- protein nitrogen.

[0099] The term “crude protein” as used refers to protein which is calculated by measuring total nitrogen content using Kjeldahl method and multiplying by a constant (6.25) to calculate the crude protein. This measurement includes any non-protein nitrogen, and nitrogen associated with protein. [000100] The term “stable” as used herein refers to a juice which, prior to pasteurisation, • has a relatively constant level of Rubisco protein as measured by SDS- PAGE, and / or • exhibits minimal observable browning as measured by PPO (polyphenol oxidase) assay, and / or • does not contain visually observable precipitated protein, and / or • has a microbial load that does not increase by more 1 log cfu / ml as measured by aerobic plate count. [000101] A constant level of Rubisco protein as measured by SDS-PAGE means a consistent intensity of protein bands as stained with Coomassie Blue dye in the SDS- PAGE gel and quantified by densitometric quantification. [000102] Unless otherwise stated, percentages herein are given on a weight basis. Since the density of juice is substantially about 1.0 g / mL, it will be appreciated that percentages on a weight (w / w) or volume (w / v) basis given herein are essentially equivalent.[000103] The term GRAS refers to a food or food ingredient generally regarded as safe for humans, and is a United States and Drug Administration (FDA) designation under sections 201(s) and 409 of the Federal Food, Drug, and Cosmetic Act. [000104] The European Union (EU) Novel Foods Regulation (EC) No 258 / 97 applies to foods and food ingredients that have not been used for human consumption to a significant degree within the European Community before 15 May 1997. According to the Novel Foods Regulation, novel foods must not present a danger to consumers; mislead consumers; or differ from foods or food ingredients for which they are intended to replace to such an extent that their normal consumption would be nutritionally disadvantageous for the consumer. The term “novel food” is used to refer to a food that complies with the Novel Foods Regulation. FIGURES [000105] The present invention will be described by way of example only and with reference to the accompanying Figures. [000106] Figure 1 shows a schematic of a process according to the invention. [000107] Figure 2 shows a schematic of another process according to the invention. [000108] Figure 3 is a side view of one embodiment of a juicing apparatus. [000109] Figure 4 is perspective view of the juicing apparatus of Figure 1. [000110] Figure 5 shows the details of some of the conduits of the juicing apparatus of Figure 3. [000111] Figure 6 is a schematic of a screw press. [000112] Figure 7 is a process flow diagram of one embodiment of the juicing apparatus of the invention. DETAILED DESCRIPTION [000113] As discussed in more detail herein, the invention broadly relates to a process for extracting a plant juice comprising protein from a plant material. A pulp that can be ensiled and / or baled is also produced by the process. In broad terms, the invention also provides a plant juice comprising commercially desirable protein levels thatis stable for at least 4 or at least 6 hours, and also an apparatus that can be used to perform the process of the invention. [000114] The plant juice will be used to produce downstream protein containing products such as Rubisco containing products including a final white protein powder primarily for human consumption. [000115] With reference to the process shown in Figure 1, the steps of pressing, refrigeration, recirculation, dosing, and storage, to produce a pulp material, and to produce a plant juice prior to transport, are all preferably carried out in a single apparatus in or close to the field from which the plant material is harvested. However, it is also possible for the step of harvesting to be included in that apparatus. It is also possible for the storage step for the plant juice to be separate from the apparatus, in which case the refrigerated and dosed extracted juice would be transferred to a separate storage / transportation unit. A further option is for the apparatus to include a baling unit for the pulp material produced as a result of the pressing step. Ordinarily, harvesting of the plant material will be done using a suitable harvester that will transfer the harvested plant material to a separate vehicle that will carry or include the apparatus for producing the juice and pulp material. [000116] Plant material, from a plant including but not limited to those described herein, is harvested according to known methods. [000117] The harvested plant material is then transferred to a pressing or juicing step which can use any suitable form of maceration device, as described in more detail herein. The maceration device or juicer can, without limitation, be a screw press, blender, or similar device, to physically separate the liquid component (juice) of the plant material from the dry matter component (pulp). [000118] To produce a silage, immediate baling of the pulp following production using a suitable baling unit on the apparatus is preferred but not essential. Collection and baling as would usually be done is also an option. It is preferred that the pulp produced is baled as soon as possible for use as stock food, which has the advantage of the pulp material not lying on the ground, avoiding leaching of nutrients from the pulp into the soil and subsequent run off issues, and a reduction in the quality of the product. [000119] The plant juice produced is then cooled using a suitable refrigeration system, such as a heat exchanger. The juice is cooled to a desired temperature of between about0.1 and about 12°C, but preferably to less than about 7ºC, more preferably less than 5oC, as described further herein. [000120] The time period between harvesting the plant material and commencing cooling of the extracted plant juice to the desired temperature is preferably less than 15 minutes. The time period should be as short as possible but, from a practical perspective, it is unlikely to be able to be shorter than about 3 minutes. If that is possible then that is included. The time period between harvesting and pressing should be between about 60 and 120 seconds preferably. It has been found that reducing the time period in this way minimises the microbial load and enzymatic activity in the juice while cooling in that period reduces microbiological growth. Recirculation of the cooled green juice into the maceration device to reduce the temperature as the plant juice is produced extends the cooling impact of the process further reducing deleterious effects on the quality of the product produced. This option is particularly applicable if the apparatus which conducts the pressing, refrigeration, recirculation, dosing, and storage steps moves with, or is attached to, the harvesting device. [000121] The apparatus can also be positioned at a suitable position in or close to the field from which the plant material is harvested. The harvested plant material can be taken to the apparatus for processing to produce the plant juice that is to be transported to a separate facility for further processing to separate the protein and other desired components from the juice to produce further desired products. In this option, it is preferred that the plant material harvested is a whole plant. The time between harvesting the plant material to production of the cooled juice should still be as short as possible to minimise the microbial load and enzymatic activity in the juice and to reduce the time in which undesired oxidation in the harvested plant materials can occur that result when the plant material is damaged. Oxidation is correlated with negative flavour and colour characteristics in the final protein products and enzymatic degradation. Again, recirculation of the cooled green juice into the maceration device to reduce the temperature as the plant juice is produced extends the cooling impact of the process further reducing deleterious effects on the quality of the product produced. This time period is preferably less than about 3 hours, less than about 2 hours, and most preferably less than about 1 hour or, if possible, less than about 15 minutes as discussed above. [000122] Reference is made herein to producing green juice “in the field”. This term includes embodiments where the apparatus is positioned in the same field from which the plant material is harvested; and also embodiments where the apparatus is positionedclose to the field from which the plant material is harvested. Typically, closeness of the apparatus to the plants to be harvested include positioning an apparatus as close to the fields from which the plants are to be harvested as possible so that travel distances are minimised and thus the time between harvesting the plant material and the juicing step is minimised. For example, the apparatus can be positioned at a distance to field(s) from which the plant material is to be harvested equivalent to a time of travel for a vehicle carrying the harvested plant material of between about 1 minute – 3 hours, for example. In practice, a hub and spoke type system could be used where apparatus are positioned in the field so that the distance between the harvesting of the plant material and the individual apparatus are within the 3 hour transport distance. It is of course preferable that this distance is a close as practicable so that the time to the apparatus from the plant material being harvested is a short as practicable. The times should preferably be between 30 minutes and 2 hours, more preferably between about 30 minutes and 1 hour. Shorter times than 30 minutes are, of course, more preferable. The apparatus could be moved as needed as will be apparent. Having the apparatus in the field allows the time between harvesting the plant material and juicing to be minimised and also allows the protein-containing plant juice produced to be transported from the field for further processing to produce protein products, such as a Rubisco protein powder. Transporting juice rather than plant material is a more efficient transportation option and allows protein deterioration in the harvested plant material to be mitigated. In the field options, however, bring potential difficulties to overcome not associated with factory based processing, such as supply of water, power, and storage capacity. [000123] A dosing composition is also added to the green juice. The dosing composition can be added before, during or after the pressing and / or refrigeration / cooling step. The dosing composition preferably comprises a reducing agent, such as sodium metabisulfite, but other suitable agents can also be used as described herein. It is preferred to add the dosing composition in a single dose after the cooling step as this allows for good control and efficacy of the dosing composition in the juice, as described herein. In addition, this allows for a portion of the cooled green plant juice without dosing composition to be recirculated into the maceration step, while the dosing composition is added to the remainder of the cooled green juice, as described herein. The inventors have found that the amount of dosing composition required can be reduced as a result of the impact of limiting the time period between harvesting and cooling as described herein. The inventors have also found that the amount of dosing composition required can also be reduced as a result of the green juice recirculation step (which is described in more detail herein). By adding the dosing composition after the plant juice produced has been cooled, more accurate dosing rates can be achieved, and dosingcomposition can be kept from transferring into the pulp produced thus keeping the maximum amount of the dosing added in the plant juice produced itself. This allows the minimum amount of dosing composition to be used to assist in maintaining the desired stability levels in the plant juice. Reduction in the amount of the dosing composition required is desirable as this at least improves the cost efficiency of the process but also results in lower amounts of external components being added to the process. [000124] This results in a plant juice product that is sufficiently stable to be able to be transported to a further processing plant and to be stored at the plant if needed prior to processing. The juice has low microbial levels, low enzymatic activity and high levels of protein. The juice for transportation will also have a temperature of preferably less than about 12ºC but preferably less than about 7ºC, and more preferably about 4°C, and will also include low amount of the dosing composition. The juice is stable, and these properties are able to be maintained for at least about 6 hours, preferably at least about 8 hours, and preferably about 2 to about 6 hours, preferably 8 hours. The plant juice comprising protein of the invention has been found to be stable for up to about 24 hours on microbiological stability testing when held at about 4ºC. Such time frames are sufficient to allow the protein containing plant juice to be transported to a processing facility for production of downstream protein products. [000125] The process includes a recirculation step, in which a portion of the cooled protein-containing plant juice is recirculated and enters the maceration device with the harvested plant material as it enters the juicing process. Alternatively, a portion of the cooled juice is recirculated and passed over the screw press(es) during the maceration process. The green juice is the juice produced from maceration of the plant material before further processing to aggregate and separate protein and other desirable components from the juice. The ratio of the portion of the cooled plant juice recirculated to the maceration device to the harvested plant material in the maceration device is preferably in the range of 2:1 to 1:2 (wt / wt), more preferably 1:1. However, this ratio can be altered as needed as would be known to a skilled person depending on the dryness of the plant material and the temperature of the plant juice generated by the maceration device. [000126] The plant material is usually relatively dry as it enters the juicing process which affects the flow of the material in the juicing process and reduces the efficiency of the juicing process and the resultant juice product produced. A liquid such as water, optionally comprising reducing agent and / or a buffering agent, can be added to the plantmaterial to improve this step, but the inventors have found that using the cooled plant juice, preferably prior to addition of the composition, as the liquid to be added provides a number of surprising advantages that are important particularly when producing the green protein containing juice in the field. Using the cooled plant juice produced by the juicing step has the advantage of avoiding the need for supply of additional water and / or buffering agent. Using the cooled plant juice addresses the dry nature of the plant material and also means that the plant material and the macerating / juicing device, such as screw press(es), are cooled during the juicing process. [000127] Maceration of the plant material generates heat which increases microbiological and enzymatic activity leading to protein degradation and the inventors have found that reducing that heat impact with cooled plant juice has efficiency and process benefits. The inventors have found that these benefits include an increase in the protein concentration of the juice produced by the process. Avoiding, or at least reducing, the need to add water / buffering agent has both environmental and economic advantages. It is important when macerating plant material in the field to produce a protein containing plant juice to keep the process and apparatus as simple and efficient as possible as avoiding unnecessary steps, additional inputs, and associated equipment reduces cost and maintenance requirements. In particular, as water use is minimised, and is preferably not added to the process, dilution of the juice produced is reduced which reduces later processing requirements needed to remove the water, and the storage and transport capacity required for the juice produced, and energy required to cool the juice are also reduced in comparison as there is less juice volume. The cooled plant juice that is transported therefore has a higher concentration of protein than if water is added. In addition, as the process includes extended cooling as a result of recirculation of a portion of the cooled juice produced into the macerating device, in addition to commencing cooling of the juice produced quickly following production, there is a reduction in microbial load and enzymatic activity in the juice produced, which improves the quality and stability of the protein levels in the green juice produced for transport. When producing plant juice in the field such issues are important to the efficiency of the process. Adding external water to cool the macerating device would require a supply of water as well as a cooling system for the water. There are also often water use restrictions that need to be addressed and balancing this against processing demands can be difficult. [000128] Increasing the pressure in the screw press or like maceration device is desirable as this will extract more juice from the plant material. Increasing pressure alsomeans that the temperature is also increased thus impacting on the amount and quality of protein in the juice produced. of the cooled green juice therefore also allows the maceration device to be used consistently at higher pressures resulting in increased juice production efficiency while maintaining protein levels and quality. [000129] The invention addresses these issues in a simple and efficient manner that is effectively self-contained while also providing a process that produces high levels of protein (Rubisco) in the juice produced. Providing an efficient means for producing the juice in the field while maintaining protein levels and quality provides a distinct benefit to the user. [000130] Temperature issues during the maceration step, such as occurs when using a screw press to produce juice from plant material for example, are known to cause issues with protein production from plant material. This is acknowledged in WO2014104880, for example, which states that enzymatic proteins, such as Rubisco, are easily damaged. Heat treatment denatures the protein and destroys functionality. WO ‘880 therefore recommends that in order to prevent deterioration of the proteins during the isolation process, it is preferred that the steps i) mechanical disruption, iii) separating of aggregated chloroplast membranes, iv) ultrafiltration, to provide a soluble plant protein concentrate, and v) hydrophobic column adsorption, and preferably also vi) drying the column permeate from the hydrophobic adsorption column of the process as described are performed under low temperature. A low temperature is said to be preferably a temperature in the range of about 0-15°C. There is, however, no description of how this low temperature effect is to be achieved. [000131] Temperature issues during the maceration stage has driven the production and use of alternative devices that avoid temperature increases. WO2022229336 and WO2023139278 for example describe the use of a rotating drum that causes the biomass to be cut into a pulp without increasing the temperature of the material, as an alternative to using screw presses. [000132] The time between the plant material entering the maceration device for extraction of the protein-containing plant juice from the harvested plant material and commencing cooling of the juice produced to the desired temperature is preferably less than about 15 minutes, more preferably less than 10, 7, or 5 minutes, preferably between about 15 and about 3 minutes. Cooling in the maceration step and of the juice produced as immediately as possible reduces product deterioration as discussed herein.[000133] It is possible to use cooled that has dosing composition added in the recirculation step, but this is less as it may result in dosing composition being transferred to the pulp produced which means that a portion of the dosing composition has been lost from the process. Also presence in the pulp could interfere with the desired development of the pulp produced into a feed product for animals. It is preferred to keep the pulp as free from non-natural components as possible. This is generally seen as desirable from food production perspective. [000134] Following production of the plant juice product in the apparatus, the juice product can be stored and / or transported as desired. The juice should continue to be kept at a temperature of less than about 12ºC but preferably less than about 7ºC, and more preferably about 4°C, but should not be frozen. The container or other storage device could therefore be suitably insulated and / or include its own refrigeration system. The plant juice product can be stored in a suitable container that could be a container suitable for transportation such as a container on a trailer adapted to be towed, or a container adapted to allow the plant juice to be removed from the container into a transportation vehicle. Such containers are well known to a person skilled in the art. [000135] Using plant juice for transport from the field to a further processing facility, and storage there if needed, is desirable as this is a more efficient way to transport and store material than transporting and storing the harvested plant material. In addition this avoids extending the time between harvesting and processing the plant material which reduces risk of product deterioration as discussed herein. [000136] Therefore, an aspect of the invention is recirculation of green juice cooled to a desired temperature of less than about 12ºC but preferably less than about 7ºC, more preferably about 4°C, or preferably between 1 and 12°C, to assist material flow and control the temperature in a maceration device (e.g. screw press(es)) when macerating a plant material. The temperature in the maceration device is able to be controlled so that the temperature of the juice produced by the device can be controlled. The temperature of the juice exiting the maceration device is preferably controlled to be below about 20ºC, preferably below about 15ºC, more preferably below about 12ºC, 10ºC, or 7ºC by using the recirculated cooled plant juice. It is important that the temperature is controlled as the temperature in a maceration device that is run at high pressure for period of time, as would be seen in commercial use, can increase rapidly which may not only impact the product production and quality but may also damage the device itself. Temperature control can be achieved by testing the temperature of the plant juice at the outlet of the juicer and then by adjusting the flow rate of therecirculated cooled plant juice into the or by adjusting the temperature that the plant juice is cooled to prior to or a combination of both. Temperature control can be manual or via an automated feedback control system including temperature sensor(s) and related flow / temperature controls as would be known to a person skilled in the art. Inclusion of this flow and temperature control option is an improvement on existing processes providing a simple and cost-effective way to address known problems and provide benefits to a user. [000137] The calculation for the amount of juice to be recirculated into the maceration device to provide a desired output temperature could be determined by a skilled worker using standard thermodynamic principles. In this way, the maceration device can continue to be run at higher and more efficient pressures while maintaining acceptable temperature levels in the juice produced and minimising product degradation. [000138] Using cooled green plant juice produced from the maceration step and before any further processing steps to reduce the temperature during the pressing stage, where temperature is an issue such as when using a screw press, would not normally be something that would be considered. This is due to the perceived risk of protein content and quality reduction in the protein that is present in the plant juice produced, as a result of the temperatures produced in the maceration device. The invention may therefore be seen to provide method of improving the flow of plant material through and controlling the temperature in a screw press when producing a protein containing plant juice, the method including the steps of (i) commencing cooling of the plant juice produced to a desired temperature, preferably below 12ºC and preferably within about 5 minutes of production by the screw press, and (ii) recirculating a portion of the cooled plant juice produced to the screw press, preferably with the plant material as it enters the screw press, to improve the flow of the plant material through the screw press and to control the temperature as the plant material passes through the screw press so that the plant juice produced and exiting the screw press is controlled to a temperature that is preferably below about 20ºC and more preferably below about 15ºC. Plant material [000139] The invention can be used to produce a plant juice and pulp from any plant material, including a plant or part of a plant. For example, a food crop plant, a fodder crop plant such as alfalfa, a plant part which is a part of a food crop plant, including a plant waste material such as the tops of tubers, or any non-food crop plant or a part thereof.[000140] It is preferred that the plant materials are harvested so that they are as undamaged as possible. The whole plant, from the root structure, can be processed. The harvester will preferably cut the plant off low on the stalk, usually between about 7cm – about 20cm above the ground, preferably about 10cm above the ground, to minimise dirt and soil detritus in the harvested material, minimise plant damage and so plant regeneration can occur where possible. The whole plant, including the leaves and woody elements (stalks, branches etc) can be processed. This is preferred when the harvested plant material is to be transported to a processing facility in the field to produce the cooled green juice for transport as this reduces undesired oxidation in the harvested plant materials that result when the plant material is damaged (as has been discussed herein). Preferably, in other embodiments, the plant material comprises green leaves. In some preferred embodiments, the plant material is generally considered as safe for humans (GRAS). [000141] The plant material can be cut by a forage harvester (e.g. CLAAS) and left on the ground, windrowed, and picked up by a wagon. The harvested plant material is transported to the juicing apparatus which is either in or close to the field with the plant material or at a centralised location between a number of fields. The crop arrives at the juicing site preferably within 30 minutes of the start of harvest. [000142] Without limitation, the plant or the plant part can be from the family Fabaceae, such as alfalfa, kudzu or forage peas; from the family Gramineae (also known as Poaceae), such as oats; from the family Lemnoideae, such as duckweed; or spinach; from the family Brassicaceae, such as kale; or roadside crops, cocksfoot, Italian ryegrass, Raphno® (kale-radish hybrid), clover, Persian clover, rapeseed leaves, carrots, radishes, Jerusalem artichoke; from the family Amaranthaceae, such as beets, spinach, fodder beet; triticale, white clover, barley, tobacco, chicory, sugar cane, or fava bean leaves. [000143] In a preferred embodiment, the plant is alfalfa (Medicago sativa, also called lucerne). As a legume, alfalfa does not require high levels of synthetic nitrogen input, reducing costs and negative environmental consequences of nitrogen application. It has year-round growth and fields do not need to be tilled and replanted every year. In another embodiment, the plant is oats (Avena sativa), which are a good catch-crop for managing excess nitrogen and soaking up excess nutrients. Juicing step [000144] The plant juice can be produced using any apparatus which is suitable for pressing, crushing or otherwise macerating the plant material, including but not limited toa screw press, a hydraulic press; a mincer; or a blender. The preferred option is to use a screw press, or screw presses which are used in series, to maximise the juice recovered from the plant material. Screw presses can be either linear straight or conical. Twin screw presses can also be used. [000145] The pressure of the ram in the screw press is controlled by air pressure of 0 - 7 bar, resulting in about 1.5T to about 9T back pressure. This results in a dry matter extraction of about 15% - about 45% from the plant material (e.g. alfalfa) into juice. The back pressure can be increased to between about 1.5T to about 20T, preferably between about 1.5T to about 18T, about 1.5T to about 15T, about 1.5T to about 10T, about 3T to about 20T, about 3T to about 18T, about 3T to about 15T, about 3T to about 10T, about 5T to about 20T, about 5T to about 18T, about 5T to about 15T, about 5T to about 10T, about 10T and about 20T, about 10T to about 18T, or about 10T to about 15T, and run consistently in the process of the invention which improves plant juice production rates. In practice, the plant juice extraction process will usually run continuously for between 6 and 12 hours in the field and, when using the process of the invention, the pressure used in the screw press can be between about 15T and 20T over that time. Being able to run the process in this manner maximises the amount of plant juice able to be extracted while keeping the temperature of the plant juice exiting the press at acceptable levels. When a plurality of screw presses is used, the back pressures of the plurality of screw presses can be the same or different as may be desired by the user. [000146] The juicing step results in a pulp that has further uses, for example it can be baled or ensiled and used as animal feed, as well as the juice of the invention. The pulp material may be passed back through the maceration device (e.g. screw press) a number of times, such as up to four times, more preferably two or three times. Depending on the plant material, the limit for effective protein extraction with the juice produced from the plant material being pressed may be three times. While more recycling of the pulp material through the press(es) may be done, this may not result in more protein being extracted into the juice. [000147] Preferably, once produced, the protein-containing plant juice is immediately cooled to a temperature of less than about 12°C, for example less than about 11, 10, 9, or 8°C, preferably to less than about 7°C. As will be clear to a skilled person, the juice should not be cooled to a temperature that results in the juice freezing. In this context, “immediately cooled” refers to a time period in which the cooling of the plant juice commences of less than about 5 minutes, for example from about 4.5 minutes, about 4 minutes, about 3.5 minutes, about 3 minutes, about 2.5 minutes, about 120 secondsabout 100 seconds, about 90 seconds, about 80 seconds, about 70 seconds, about 60 seconds, about 50 seconds, about 40 and preferably about 30 seconds. The cooling step can aid the prevention of chemical or enzymatic activity and can mitigate the heat of friction produced during the juicing step. Immediate commencement of cooling suppresses microbiological activity and diminishes the rate of chemical reactions present at ambient or elevated temperatures. The time period from maceration of the harvested plant material to commencement of cooling of the plant juice produced to the desired temperature is preferably less than about 15 minutes, more preferably less than 10, 7, or 5 minutes. [000148] Preferably, once the juice is produced and has been cooled to the desired temperature, a dosing composition (as described herein) is immediately added to the juice. In this context, “immediately added” refers to a time period of less than about 90 seconds, for example from about 90, about 80, about 70, about 60, about 50, about 40, or about 30 seconds, preferably about 20 seconds. This can aid in the prevention of chemical and enzymatic activity and is discussed further below. [000149] A portion of the plant juice produced and cooled is recirculated into the maceration device with the plant material which is being crushed or pressed in the maceration device for extraction of protein containing plant juice. Control of cooled plant juice entry into the maceration device to mitigate loss of plant juice from the process is desirable. Recirculation of a portion of the extracted plant juice that has been cooled to the desired temperature with the plant material as it enters the maceration device or over the maceration device (such as a screw press) as it macerates the plant material has been found to increase the protein extracted from the plant material into the juice. As raw plant material passes through the juicing machine such as a screw press(es), juice is expressed, and the raw plant material becomes dryer. Addition of an aqueous solution (i.e. the cooled juice) over the press at this point means soluble materials still present in the plant material in the maceration device are more readily extracted into the juice than if plant juice was not added. In addition, the cooled juice lowers the temperature produced by the macerating device (such as a screw press) as it processes the plant material. Lowering the temperature to so that the juice produced from the maceration device is below about 20ºC, below about 15ºC, below about 12ºC, below about 10ºC, or below about 7ºC, also improves the efficiency and quality of the protein production as it reduces the likelihood of higher temperatures impacting plant juice production and quality. The inventors have found that extracted protein yield concentration in the plant juice produced was higher when cooled plant juice already extracted from the plant material was recirculated, instead of water or a buffering agent.Use of the cooled plant juice instead of water is also desirable because it reduces the amount of water required to be added to process, meaning less energy is required to remove the water during later processing steps, and less storage capacity is needed in the field as the plant juice has a higher protein concentration. Less water usage has environmental as well as commercial benefits as has been previously discussed. [000150] When recirculating a portion of the cooled plant juice it is preferred that the juice recirculated into the plant material does not contain the dosing composition. This can be achieved by separating out the portion of the juice to be recirculated into the plant material, after it has been cooled but before adding dosing composition to the remainder of the juice. The reason for this is to prevent the dosing composition entering the pulp produced thus reducing dosing composition loss and preventing its presence in animal food (e.g. silage) made from the pulp as has been discussed previously. The dosing composition is further discussed below. Dosing composition [000151] The protein recovery from the protein containing plant juice produced can be increased by the addition of a dosing composition. The dosing composition can comprise one or more of: a reducing agent, chelating agent, pH modifying agent, mono, divalent or trivalent metal ions, a precipitant, minerals, a filter aid, or a modifying buffer or co-solvent. In some embodiments, the dosing composition comprises a reducing agent. The reducing agent can also be termed an antioxidant. [000152] Examples of reducing agents suitable for use in the invention include: ascorbic acid, citric acid, oxalic acid, cysteine, dithiothreitol (DTT), dithioerythritol (DTE), tris(2-carboxyethyl)phosphine (TCEP), β-mercaptoethanol (BME), sodium dithionate, nitrilotriacetic acid (NTA), Cysteamine, Glutathione (GSH). The reducing agent may be added to provide a concentration in the juice of from 0.5 to 50 mM. [000153] Examples of chelating agent suitable for use in the invention include: ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), tripolyphosphate, pyrophosphoric acid, hexametaphosphate, EGTA, glycine, poly-lysine, oxalic acid, citric acid, tartaric acid, decolourising charcoal, polyvinylpyrrolidone, and salts and polymer stabilised or derivatised versions thereof. [000154] Examples of pH modifying agents suitable for use in the invention include: permitted pH adjusting agents, acid-reacting materials, base reacting and water correcting agents including organic acids such as acetic acid, ascorbic acid, citric acid,lactic acid, tartaric acid, adipic acid, fumaric acid, malic, acid, gluconic acid, and the alkali metal or ammonium salts thereof, and metal, ammonium salts or protonated forms of sulfates, carbonates, bicarbonates, hydroxides, phosphates, chlorides, oxides, and nitrates. [000155] Examples of mono, divalent or trivalent metal ions suitable for use in the invention include: lithium, sodium, potassium, magnesium, calcium, aluminium provided as salts, compounds, or counterions. [000156] Examples of precipitant, flocculant, minerals, and filter aids suitable for use in the invention include: polylysine, chitosan, polyacrylamides, iron sulfates, or other cationic or anionic polymers, a modifying buffer or co-solvent such as polyglycol ether, oleic acid, or anti-foam. [000157] Preferably, the dosing composition comprises metabisulfite, and can comprise for example sodium metabisulfite, a known inhibitor to enzymes and an antioxidant which also reduces browning reactions (Edwards et al., Journal of agricultural and food chemistry, 23, 620-626 (1975)). [000158] The dosing composition can be added before, during or after the juicing step. For example, a solution containing the dosing composition can be sprayed onto the plants prior to harvest; or can be added into the juicing apparatus during the juicing step, or can be added to the juice after the juicing step. It is preferred in the present invention to add the dosing composition after the juicing step in the maceration device and after the cooling step, and after a portion of cooled plant juice has been removed for recirculation. This provides for good control of chemicals added to the juice, preferably via fixed dosing, resulting in less dilution of the protein content of the juice, less weight / volume to the juice, and where the dosing composition comprises a mineral, fewer minerals in the final product. The components of the dosing composition should be chosen with reference to food safety standards and target product attributes. [000159] Preferably, the dosing composition is added to the juice immediately after extraction from the plant material and juice cooling, to reduce chemical and enzymatic activity. In this context, “immediately added” refers to a time period of less than about 90 seconds, for example from about 90, about 80, about 70, about 60, about 50, about 40, or about 30 seconds, preferably about 20 seconds. [000160] The dosing composition may be a solid, or a liquid composition. In a preferred embodiment, the dosing composition is a powder or is an aqueous composition.The dosing composition preferably sodium metabisulfite, and the dosing composition is preferably added to the juice in an amount to provide a concentration in the plant juice for transportation from about 0.005% to 2.0% (w / v), for example from about 0.005% to about 1.8%, about 0.005% to about 1.6%, about 0.005% to about 1.4%, about 0.005% to about 1.0%, about 0.005% to about 0.8%, about 0.005% to about 0.6%, about 0.005% to about 0.4%, about 0.005% to about 0.3%, about 0.005% to about 0.2%, about 0.005% to about 0.1%, about 0.005% to about 0.05%, about 0.005% to about 0.04%, about 0.01% to about 2.0%, about 0.01% to about 1.8%, about 0.01% to about 1.6%, about 0.01% to about 1.4%, about 0.01% to about 1.0%, about 0.01% to about 0.8%, about 0.01% to about 0.6%, about 0.01% to about 0.4%, about 0.01% to about 0.3%, about 0.01% to about 0.2%, about 0.01% to about 0.1%, about 0.01% to about 0.05%, about 0.01% to about 0.04%, preferably about 0.02% (w / v). This may be achieved with the dosing composition being for example a powder or a 20% aqueous solution concentrated stock. Concentration of dosing composition in the plant juice are also preferably below about 0.03% w / v, or about 0.02% w / v. [000161] The dosing composition can be added using dosing mechanism such as a control system including a flow meter to measure the flow of juice. The dosing mechanism will be configured to add the dosing composition to the juice based on the mass flow of juice measured, as will be known in the art, to achieve the amount of dosing composition desired in the plant juice produced. Plant juice [000162] Enzymes present in plants and plant parts include polyphenol oxidase (PPO), lipoxygenase (LOX), peroxidase (POX), proteases, and other degradative enzymes. PPO is responsible for “enzymatic browning” caused due to plant senescence processes. PPO causes polyphenolic compounds to oxidise, aggregate together, and bind to protein. The binding of polyphenolic compounds to the protein reduces protein digestibility. It can also cause the protein to be browner in appearance, which is undesirable in a consumer product. The association of polyphenolic compounds with the protein can also causes the protein to have a bitter or astringent taste. LOX can oxidise fatty acids causing them to have a bitter or rancid taste. POX produces free radicals which can degrade plant tissue. Therefore, it is desirable to reduce activity of these enzymes in the harvested plant material and plant juice. [000163] The inventors have observed that ensiling or fermentation processes which begin in a plant material as soon as the plant material is harvested cause an immediateincrease in senescence rate. Without to be bound by theory, it is also postulated these ensiling or fermentation processes cause an immediate increase in in temperature. [000164] When coupled with the increase in temperature which occurs during the juicing step when using macerating devices such as screw presses, the inventors have realised that these factors lead to a compromise in product quality which is compounded by any delay between harvest and juicing. The increased senescence rate increases the activity of the PPO, LOX, POX and other enzymes discussed above. [000165] When plants are harvested, a number of processes begin: dehydration commences due to absence of stem / root connection flow, stomata close and plant temperature control due to transpiration (a cooling effect) is diminished, plant wounds lead to loss of juice which can create a more humid environment in stacked or piled plant material when compared to standing plants due to diminished airflow. Wounds provide an opportunity for microbial infiltration into the plant, and weeping juice provides a liquid media exposure for microbes external to the plant, and increased humidity favouring microbial growth. The increase in temperature causes an increase in microbiological activity. Microorganisms naturally present in close association with plants respond to multiply with the increase in temperature, resulting in growth and larger microbial load in the resulting juice. [000166] A delay in juicing, a delay in commencement of production, and / or elevated temperature is associated with a greater risk in production. Under favourable conditions the growth of microorganisms can occur quickly, for example Escherichia coli, Bacillus cereus, Salmonella, Listeria, and aerobic coliforms can have doubling times of less than 30 minutes, and in some cases less than 15 minutes. Thus, growth of microorganisms can be significant and have meaningful outcomes in relation to product quality, safety and functionality in short time periods. The implications of elevated or uncontrolled microbial growth include a decrease in recoverable protein yield and efficiency due to microbial derived degradation or proteolysis of proteins, spoilage of juice due to adverse microbial derived flavours, or contamination with microbial or fungal derived toxins. From an industrial processing and human food safety perspective, rapid initial growth of microorganisms, prior to commencing the protein extraction and purification processes, affects the ability to achieve production of a product which meets acceptable microbial contamination regulations or guidelines. Exceeding these guidelines during or at the conclusion of manufacture may require additional processing steps to reduce microbial load, or discard of product which carries financial implications.[000167] For these reasons, in one embodiment of the process of the invention the juice is produced within 15 minutes, within 7 or 5 minutes, of harvesting the plant material. The temperature of the juice is controlled by commencing cooling the juice within about 15 minutes, preferably within 7 or 5 minutes, of extraction of the plant juice from the plant material as discussed herein. The inventors have also found that the time from harvesting the plant material from the field to juicing the plant material in the maceration device can be up to about 3 hours without significant loss in product quality using the process of the invention particularly when the plant material is harvested as a whole plant as discussed previously herein. Control of the temperature in and plant material flow through the macerating device used to produce the juice using a portion of the cooled plant juice initially produced provides a final green protein containing plant juice with a high protein content. Addition of a dosing composition to the cooled juice after portions are removed for recirculation results in plant juice product that has high levels of protein and suitable stability for transport to and storage at a further processing facility where the juice will be processed to produce protein (Rubisco containing) products. [000168] The juice produced can have one or more beneficial characteristics selected from decreased PPO activity; decreased total oxidized polyphenolic content; decreased modified proteins associated with chemical or enzymatic modification, lower protein colour (related to PPO levels), increased extractability and quality of macronutrients; improved flavour and colour in products of the juice; decreased oxidized-lipid content; decreased microbial load; increased total Rubisco protein concentration; and decreased acidity indicating decreased microbiological degradation and activity. [000169] Transporting parts of the plant to the macerating device in the juicing apparatus using the process of the invention in the field is possible but the time between harvesting the plant parts and maceration will be shorter to mitigate the impact of plant damage from oxidation on protein quality. This option is therefore less preferred. The time between harvesting the plant material to production of the cooled juice in this embodiment should still be as short as possible to reduce the time in which undesired oxidation in the harvested plant materials can occur that result when the plant material is damaged. This time period is preferably less that about 3 hours, less that about 2 hours, and most preferably less than about 1 hour. [000170] The inventors have found that the microbial load of the plant juice comprising protein produced by the process of the invention results in a plant juicecomprising protein having a level of microbial load low enough to be able to produce a protein powder that meets acceptable contamination regulations or guidelines. The level of microbial load in the cooled protein containing plant juice of the invention is low enough for standard processing to be used to produce a protein powder that meets acceptable microbial contamination regulations or guidelines. Additional steps and apparatus are not needed to ensure that the protein powder produced meets acceptable microbial contamination regulations or guidelines. This provides an advantage to the user particularly as the plant juice can be produced in the field for transportation adding to the overall efficiency of the process. [000171] The use of a portion of the cooled protein containing plant juice produced before protein aggregation and separation steps to assist the flow of plant material through the macerating device and to control the temperature in the macerating device and of the plant juice from the device allows the production of a green plant juice in the field that contains commercially desirable levels of protein (including Rubisco). Recirculation of the cooled green plant juice can be used when the plant material is harvested and immediately macerated, and when the plant material is taken to a juicing station in the field, to produce a cooled green protein containing plant juice for transport to a separate processing facility. In both embodiments, use of the recirculation step improves the production of the green plant juice as discussed herein. Following cooling and extraction of a portion of the cooled plant juice for recirculation, the juice can then have a dosing composition added to improve stability of the juice for transport to and storage at a further processing facility where the protein is separated from the juice and protein containing products produced. The invention therefore includes the use of such a recirculation process to produce a green plant juice and subsequent products, and to an apparatus for carrying out such a process (as will be described later herein). [000172] The beneficial characteristics can be identified using analytical methods including for example Polyphenol Oxidase assay or Catechol Oxidase Assay to measure total PPO activity, Folin-Ciocalteu (FC) method to measure polyphenolic content; methods of analysis approved by Association of Official Agricultural Chemists (AOAC, US) for extractability of macronutrients including ash content (AOAC 923.03), dietary fibre (AOAC 985.292003), fat content: (AOAC 922.06), protein content: (AOAC 981.10 mod.), nitrogen: (AOAC 981.10 mod.); methods of analysis approved by Food Standards Australia New Zealand (FSANZ) code: carbohydrates: (1.2.8 FSANZ) energy: (1.2.8 FSANZ); total solids (102°C 2 hrs c / w) gravimetry; gas chromatography olfactometry (GCO) to assess flavour; GC-MS or HPLC-MS for oxidized-lipid content; AOAC methods for micronutrients, vitamins and minerals fatty acid profile (as product basis) (AOAC991.39; AOAC 963.22); sugar profile: (AOAC 980.13; J. AOAC 75 (1992)), sodium (ICP- OES) (AOAC 984.27 mod.), minerals: ICP-OES / AES or AAS; vitamin A (AOAC 992.06), vitamin D3 (AOAC 992.26), vitamin E (AOAC 992.03), vitamin K1 (AOAC 992.27), Vitamins B1, B2, B3, B5, B6, B7, B9: LCMS, HPLC-DAD, HPLC-DAD, UHPLC- FLD; and dye-binding spectrophotometric measures, sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE), HPLC, SDS-capillary electrophoresis to measure total Rubisco protein. Protein and carbohydrate content of juice [000173] The juice contains both proteins and carbohydrates. [000174] The plant juice of the present invention comprises a high level of protein, which contains a high proportion of Rubisco protein. The high level of protein and Rubisco protein can thus be maintained throughout further processing into final protein- containing products. [000175] In various embodiments, the crude protein content of the juice is from about 5 to about 65% on a dry weight basis, for example, from about 5 to about 60%, about 5 to about 55%, or about 5 to about 50%, or about 5 to about 45%, or about 5 to about 40%, or about 10 to about 65%, or about 10 to about 60%, or about 10 to about 55%, or about 10 to about 50%, or about 10 to about 45%, or about 10 to about 40%, or about 15 to about 65%, or about 15 to about 60%, or about 15 to about 55%, or about 15 to about 50%, or about 15 to about 45%, or about 15 to about 40% on a dry weight basis. [000176] In various embodiments, the total protein (crude protein number by subtracting non-protein nitrogen) content of the juice is from about 15% to about 35% on a dry weight basis, for example from about 15 to about 32%, or about 15 to about 30%, or about 16 to about 35%, or about 16 to about 32%, or about 16 to about 30%, or about 18 to about 35%, or about 18 to about 32%, or about 18 to about 30%, or about 19 to about 35%, or about 19 to about 32%, or about 19 to about 30% on a dry weight basis. [000177] In various embodiments, the plant juice comprises protein of which at least about 10% by weight of total protein is Rubisco, for example the plant juice comprises protein of which at least about 15%, or about 20%, or about 25%, or about 30%, or about 35%, or about 40%, or about 45%, or about 50% is Rubisco.[000178] In various embodiments, the content of the juice is from about 5% to about 50% on a dry weight for example from about 5% to about 40%, or about 5% to about 35%, or about 5% to about 30%, or about 5% to about 25%, or about 5% to about 20%, or about 10% to about 50%, or about 10% to about 40%, or about 10% to about 35%, or about 10% to about 30%, or about 10% to about 25%, or about 10% to about 20%, or about 15% to about 50%, or about 15% to about 40%, or about 15% to about 35%, or about 15% to about 30%, or about 15% to about 25%, or about 15% to about 20%. [000179] Ash and fat can also be present in the juice at low amounts with respect to the dry weight, as discussed below. While the above ranges indicate a possibility to exceed 50% for more than one component, it will be apparent to the person skilled in the art that in a given juice, the percentage of components on a dry weight basis sums to 100%. Other non-measured components may also be present such as minerals, non- protein nitrogen, and secondary metabolites. [000180] The properties of the juice vary according to the time of harvest and the type of plant material being juiced, as well as the process conditions, including recirculation conditions. [000181] Advantageously, the presence of carbohydrates means that further processing of the juice into a protein product may not require a plasticizer, or may require much lower levels of additional plasticizer, providing supplementary functional benefits. Plasticizers are used as additives in foods. For example, gum Arabic is a natural gum plasticiser used as a food additive, stabiliser, thickener, with properties similar to glue. The carbohydrates in a spray dried powder formed from the juice of the invention comprise arabinogalactans (AGs) and glucuronic acid (GlcA), also found in comparable proportions in gum Arabic. [000182] Carbohydrate content can be tested in-line using near-infrared (NIR) techniques or a sugar refractometer (Brix meter), and carbohydrate content and carbohydrate composition of resulting dried products can also be tested using spectrophotometric methods, HPLC, or constituent sugar analysis. Other contents of juice [000183] The total solids content of the juice is from about 3% to about 20%, for example, from about 3% to about 18%, or about 3% to about 16%, or about 3% to about 15%, or about 3% to about 12%, or about 5% to about 20%, or about 5% toabout 18%, or about 5% to about 16%, or about 5% to about 15%, or about 5% to about 12%, or about 7% to about 20%, or 7% to about 18%, or about 7% to about 16%, or about 7% to about 15%, or about 7% to about 12% on a dry weight basis. [000184] The fat content of the juice is from about 2% to about 15% on a dry weight basis, for example from about 2% to about 14%, or about 2% to about 12%, or about 2% to about 10%, or about 2% to about 8%, or about 2% to about 7%, or about 2.5% to about 15%, or about 2.5% to about 14%, or about 2.5% to about 12%, or about 2.5% to about 10%, or about 2.5% to about 8%, or about 2.5% to about 7% on a dry weight basis. [000185] The ash content of the juice is from about 3% to about 30% on a dry weight basis, for example from about 3% to about 25%, or about 3% to about 20%, or about 5% to about 30%, or about 5% to about 25%, or about 5% to about 20%, or about 7% to about 30%, or about 7% to about 25%, or about 7% to about 20%, or about 10% to about 30%, or about 10% to about 25%, or about 10% to about 20% on a dry weight basis. [000186] The total solids, ash, and fat are measured using AOAC standard methods mentioned above. [000187] In one embodiment, the juice comprises: • A total solids content of from about 7.0-12.0%, • A total protein content of from about 19-26% on a dry weight basis, • A carbohydrate content of from about 30-40% on a dry weight basis, • A fat content of from about 2.5-7.0% on a dry weight basis, and • An ash content of from about 10-20% on a dry weight basis. Microbial load of juice [000188] The juice of the invention advantageously has a low microbial load. This confers increased storage stability on the juice, and also can reduce or obviate the need to remove microorganisms or microorganism derived contaminants using an additional downstream processing step. “Microbial load” is a term used to describe the number of microorganisms within a product such as a food product. A microbial load is comprised ofindividual microbiological counts of species, the colony forming units (cfu) of each of which may be counted. A unit (CFU) is a unit used to estimate the number of viable bacteria in a sample. Determining colony-forming units requires culturing the microbes and counts only viable cells, i.e., those able to multiply and form a visible colony. [000189] The inventors have found that plant juice produced according to the invention and cooled to about 4°C has a microbial load of less than about 1,000,000, or about 600,000, or about 500,000 cfu / mL after about 9 hours, measured by aerobic plate count (APC). This makes it suitable for preparing a protein product with a microbial load of less than 50,000 cfu / mL, measured by aerobic plate count using e.g. a standard pasteurisation process which can provide a 3-log reduction in APC. [000190] Microbial load may be measured by performing microbiological culture experiments on media selective for the species of interest and counting the number of discrete colonies that grow on the selective media. The number of colonies, or colony forming units (cfu) is calculated and reported at cfu / (mL) or cfu / (gram) of product being analysed. [000191] There are a number of species of microorganisms which may be of concern in relation to foodstuffs, including Escherichia coli, Listeria monocytogenes, Salmonella spp., Bacillus cereus, and yeasts and moulds. [000192] The regulatory and guideline tolerances for microbial species varies in proportion of the pathogenicity of the species. There are maximum microbial load criteria (cfu / g) specified for most foods in food standards guidelines in various jurisdictions throughout the world, which are used to make decisions on food safety criteria and for process hygiene criteria. A juice produced according to the current invention can be used to produce foods which meet these requirements, as discussed above. [000193] In preferred embodiments, the microbial load can be monitored for species including Escherichia coli, Listeria monocytogenes, Salmonella spp., Bacillus cereus, yeasts and moulds, aerobic spore-forming mesophilic bacteria, spore-forming Clostridium spp., aerobic spore-forming thermophilic bacteria, Staphylococcus aureus, and Enterobacteriaceae spp. Preferably, testing in relation to the microbial load is conducted in a laboratory accredited under ISO / IEC 17025. [000194] Plant juice microbial load can be reduced via hygiene and processing steps such as filtration, sedimentation, high pressure pasteurisation, thermal pasteurisation,pulsed electric field. These and other methods known to a skilled person have been demonstrated to microbial load counts in juice and plant juice derived protein products by factors of log 3 to log 5, to achieve a cfu / ml values to less than 50,000 cfu / ml on final specification. [000195] Higher microbial load counts of about 5,000,000 cfu / mL, about 10,000,000 cfu / mL and up to about 25,000,000 cfu / mL may be recorded. Higher microbial load may require additional or more extensive processing to bring microbial load to within a desired specification. This increased processing can cause degradation or a decrease in the functional attributes of the soluble proteins. Polyphenolic content of juice [000196] Polyphenolic compounds present in many plant foods are commonly referred to as tannins. Tannins as a descriptor can refer variously to large condensed and polymerised polyphenolic molecules, and to smaller polyphenolic compounds which include both large and small polyphenolic molecules, such as the small molecule gallic acid. Both tannins and oxidised polyphenols are brown and can bind to proteins, and so contribute to a brown colour in a white protein powder or other products produced from the juice which is unfavourable from a consumer or food formulation perspective. [000197] The presence of large condensed and polymerized polyphenolic molecules can be tested using precipitation, tests with iron binding, or tests which seek to determine the extent of phenolic rings. Preferably, the juice of the invention does not comprise large condensed and polymerized polyphenolic molecules which can be detected with such testing. [000198] The polyphenolic content of the juice of the invention can be measured using the Folin-Ciocalteu (FC) method, which is a measure of phenolic and polyphenolic antioxidants against a reference standard of gallic acid equivalents (GAE). [000199] In preferred embodiments, the juice of the invention has a polyphenolic content of less than about 6%, for example less than about 5%, less than about 4%, less than about 3%, or preferably less than about 2% (GAE). [000200] In preferred embodiments, the polyphenolic content of the juice of the invention is sufficiently low to reduce or obviate the need for additional processing steps directed to removal of polyphenolic compounds, such as hydrophobic column adsorption.[000201] The invention therefore includes a plant juice that is stable for between about 2 and about 6 hours, the juice a low microbial load and low enzymatic activity. When stored at a temperature of about 4°C the juice of the invention can be stable for up to about 24 hours. [000202] The juice preferably comprises, on a dry weight basis, a protein content between about 5-50%, for example about 10-35%, and a total carbohydrate content between about 5-50%, for example about 15-40%. The juice further preferably comprises a polyphenolic content of less than about 6%, for example less than about 5%, less than about 4%, less than about 3%, or preferably less than about 2% (GAE), and / or a microbial load of less than about 1,000,000 after 9 hours measured by aerobic plate count. [000203] The invention therefore provides a plant juice extracted from a plant material, the plant juice comprising a protein content of between about 5-50% on a dry weight basis, the plant juice having a temperature of less than about 12ºC and being stable for at least 4 hours. [000204] It is preferred that the plant juice comprises a protein content of between about 10-35% on a dry weight basis, and a total carbohydrate content of between 15- 40% on a dry weight basis. [000205] It is further preferred that the plant juice comprises a reducing agent, such as sodium metabisulfite, in an amount of between 0.005% to 2.0% (w / v). [000206] It is further preferred that the plant juice comprises a polyphenolic content of less than about 6%. [000207] It is further preferred that the plant juice has a temperature of less than about 7ºC, more preferably about 4°C. [000208] It is further preferred that the plant juice is stable for at least 6 hours or at least 8 hours. [000209] The process of the present invention is able to produce a stable plant juice that comprises a high level of protein, which has a high proportion of Rubisco protein. The plant juice may comprise a protein content of between about 5 to about 50% on a dry weight basis. The Rubisco content may be at least about 10% by weight of protein, or example about 40% by weight of protein. The plant juice may have a temperature of less than about 12°C, for example less than about 5°C. The plant juice may have adosing agent such as sodium metabisulfite in an amount of less than about 0.03% w / v. The plant juice may have a polyphenolic of less than about 6% w / w. The plant juice may have a microbial load of less than about 600,000cfu / ml after about 4 hours. [000210] Transportation of the cooled plant juice comprising protein will preferably be in a tank that is able to maintain the temperature of the plant juice at a constant desired temperature. Preferably this will be below 12°C and more preferably below 5°C as discussed previously. The transportation may also be in a tanker that has a container that is insulated but not refrigerated which may result in the temperature of the plant juice rising in the time between loading the plant juice comprising protein and delivering the cooled plant juice to the further processing facility where the protein is to be extracted from the plant juice. Such temperature rises when transporting cooled products will be well known to a skilled person and is usually about 0.5°C – 2°C over a 2hour period for products such as milk that are routinely delivered in such a manner. The plant juice comprising protein of the invention will be able to maintain its stability levels when transported in such a manner and the temperature of the plant juice produced can be adjusted to manage issues that may arise. Pulp [000211] The pulp of the invention has a number of uses, including baling for animal feed, and ensiling to produce silage for animal feed. Optionally, minerals and other components can be added to the animal feed or silage to provide dietary supplements such as phosphorous and other minerals. [000212] In embodiments where the pulp is ensiled to produce a silage, the silage can have a nutritional profile comparable to ordinary silage produced without juice extraction. Thus, the process of the invention can be used to extract juice from an ordinary silage crop to provide the juice in addition to the silage ordinarily obtained from the crop. [000213] Figure 2 shows an alternative process using two (or more) screw presses in series according to a process of the invention as described herein. In Figure 2, harvested fresh crop enters a first screw press (Press 1). A first juice (Juice 1) is produced and immediately cooled (T) by a Chiller. A portion of Juice 1 is recirculated to screw press 1 and the remainder of the cooled juice is sent to the storage silo for transport by a tanker. [000214] The pulp produced from Press 1 enters a second screw press (Press 2) from which a second juice (Juice 2) is produced. In a manner similar to Juice 1, Juice 2 isimmediately cooled (T) by a second Chiller. A portion of cooled Juice 1 is recirculated to the second screw press (Press 2) and the is sent to the storage silo for transport. It is possible for other recirculation options to be used as would be apparent to a skilled person when in possession of the invention, such as cooled Juice 2 being used for recirculation to Press 2 for example. The pulp from Press 2 can be baled or ensiled or can be sent to a third screw press (not shown) as desired. [000215] In the process of Figure 2, a dosing agent (Reducing agent) is added to the juice. It would be preferable for this to be added as an aqueous solution of the reducing agent (e.g. sodium metabisulfite) to avoid localisation effects in the juice that can occur if added as a powder. Localisation could also be addressed using an agitation device in the silo and such matters would be known to a skilled person. [000216] The details of the process shown in Figure 2 are as otherwise described previously herein and various options to the steps shown can be used if desired. For example, the screw presses can be operated at pressures that are the same or are different. As will be apparent, a screw press using recirculation of the cooled plant juice could be used with a press not using recirculation. This may be done to improve the efficiency of an existing extraction system. While not preferred, such options may be used if required. Further processing of juice Further storage and transport of juice [000217] Once produced, the juice is kept at a cool temperature for storage and / or transport before further processing. For example, it can be transferred to a refrigerated tanker or other refrigerated transport, to be maintained at a temperature of less than about 12°C, for example less than about 11°C, 10°C, 9°C, or 8°C, more preferably less than about 7°C. Coagulation to produce a total precipitated protein product [000218] The plant juice contains both green proteins and white proteins. The green protein components comprise chlorophyll and chlorophyll-containing proteins, large carbohydrates, residual cell-wall material and membrane fragments. The “non- green” protein fraction is comprised of water-soluble proteins, mainly Rubisco, and is commonly referred to as the “white protein”. A total protein product can be produced from the plant juice using a process which non-selectively coagulates both fractions, such as acid treatment, heat treatment or flocculation.Heating and chilling step to produce brown and green protein material [000219] The green protein fraction can be coagulated under milder conditions than the white protein fraction. For example, a mild heat treatment can be used to coagulate the green protein fraction and leave the white protein fraction in solution. [000220] In a preferred embodiment, this step provides heating of the juice to a separator. The juice is held at elevated temperature, for example in a range of between about 40ºC to about 60ºC or between about 45ºC to about 60ºC, for a period of time between 15 seconds and 2 hours. Temperature can be monitored during this step, and controlled for example using a heat exchanger such as a shell in tube, tube-in-tube, or plate heat exchanger, or direct steam injection. After the heating step the temperature of the juice is preferably lowered to less than about 12°C, for example less than about 11°C, 10°C, 9°C, or 8°C, more preferably to less than about 7°C, in order to control microbial growth and enzymatic activity. [000221] In an alternative embodiment, the coagulation can be carried out by flocculation. For example, a chemical flocculant such as calcium chloride can be added at an example concentration of 20 mM which forms flocs in solution that then coagulate together. Separation step to produce brown juice and green protein material [000222] Once coagulation has occurred, the green protein can be separated from the liquid to provide a brown juice and a green protein material sludge or liquid suspension. This can be achieved using a lab centrifuge, disc stack centrifuge (i.e. industrial separator), clarifier, decanter, sedicanter, filter press / coarse filter, settling tank, or hydrocyclone. If a separator is used, coagulated juice can be fed to the separator via a pump. The separator spins coagulated material out into the discharge to form a green “pellet” leaving a clarified brown juice which contains the white Rubisco protein. Filtration step [000223] The brown juice can then be subjected to microfiltration, for example using cross-flow filtration, dead end filtration, a syringe filter, or a filter press. Filtration pore sizes can range between 0.05 and 10 µm, for example 0.1 µm, 0.2 µm, 0.45 µm, 0.5 µm, 0.8 µm, 1.0 µm, 1.2 µm, 1.4 µm, 1.6, µm 1.8 µm, or 2.0 µm. Microorganisms are removed at the microfiltration step. Advantageously, the low microbial load of the juice obtained from the plant material according to the invention results in a brown juice witha corresponding low microbial load, the load on the microfilters, and reducing or obviating the need for additional steps directed to removal of microorganisms. Soluble proteins pass through the filter, while large carbohydrates, residual cell-wall material, and microorganisms are retained on the filter. Purification step [000224] Purification of the brown juice can be achieved by ultrafiltration, which results in a permeate which has a high content of monosaccharides, sugars and minerals that is sometimes alternatively termed a “molasses” composition, and a purified protein retentate. Optionally, before ultrafiltration the pH of the brown juice can be adjusted to a range of 8-10. This step can suitably use an ultrafiltration / diafiltration scheme. Filtration pore sizes can range between 1 and 1000 kDa, for example 500 kDa, 300 kDa, 100 kDa, 70 kDa, 50 kDa, 30 kDa, 10 kDa, and 5 kDa. Concentration step, drying step [000225] The retentate collected from the purification step can be further concentrated and then dried, for example by spray drying or freeze drying. [000226] In some embodiments, the dried retentate may be further processed into forms suitable for storage. In some embodiments the dried retentate may be combined with additives including cryoprotectants, lyoprotectants, flowing agents, glidants, binding agents, bulking agents, anti-caking agents, lubricants, fillers, sweeteners, excipients including colourants, flavouring agents but not limited thereto. APPARATUS [000227] The invention also provides an apparatus for extracting a green plant juice from plant material by the process of the invention as previously described. [000228] With reference to Figures 3 to 7, there is shown one embodiment of a juicing apparatus, indicated generally by reference number 1. The juicing apparatus 1 is shown in a harvest site 3 having a ground surface 5 and a crop of plant material 7. Without limitation, the plant or the plant part can be from the family Fabaceae, such as alfalfa, kudzu or forage peas; from the family Gramineae, such as oats; from the family Lemnoideae, such as duckweed; or spinach; from the family Brassicaceae, such as kale; or roadside crops, cocksfoot, Italian ryegrass, Raphno® (kale-radish hybrid), clover, Persian clover, rapeseed leaves, carrots, radishes, Jerusalem artichoke; from the familyAmaranthaceae, such as beets, spinach, fodder beet; triticale, white clover, barley, tobacco, chicory, sugar cane, or fava [000229] The juicing apparatus 1 is configured to remove liquid (i.e. green protein containing plant juice) from the plant material 7 after the plant material has been harvested from the harvest site 3. The various features and operation of the apparatus 1 are described below. [000230] The apparatus 1 has a single vehicle 9 with a body 11 and a plurality of wheels 13. The plurality of wheels 13 are configured to support the vehicle body 11 above the ground surface such that the apparatus 1 can travel across the harvest site 3. In some embodiments, the vehicle 9 has an engine. The engine may be any suitable engine, such as an internal combustion engine, electric engine, hybrid engine (Internal combustion engine + electric engine), or fuel cell hydrogen vehicle. The vehicle 9 may be a tractor, truck, car, utility vehicle, or bulldozer, for example. In other embodiments, the vehicle 9 may not have an engine. The vehicle 9 may be a trailer or trolley that is pushed or pulled by a further vehicle with an engine. In other embodiments, the apparatus may not have wheels or an engine, and may be stationary. The apparatus may also be configured to be transportable such that it can be taken to and placed at a suitable site. [000231] The accompanying drawings in Figures 3 – 5 show a single vehicle 9 that supports a juicer 15, juice outlet 21, the cooling system, and the dosing mechanism. In an alternative embodiment, the apparatus may comprise two or more vehicles 9, and the juice outlet 21 and juicer 15 may be on separate vehicles 9. Additionally or alternatively, the cooling system and juicer 15 may be on separate vehicles 9. Additionally or alternatively, the dosing mechanism and juicer may be on separate vehicles. In another embodiment, the apparatus may be stationary and comprise the juicer 15, juice outlet 21, the cooling system (such as refrigeration system 35), the recirculation system 57, and the dosing mechanism 27. A storage system, such as an insulated or refrigerated tank 41 may also be included. The storage system would be capable of maintaining the temperature of the plant juice stored therein at a desired temperature, which may be at or about the same temperature at which the plant juice has already been cooled to or which may be at a different temperature as may be desired for storage and transport. Such a storage system would also be capable of allowing the plant juice stored therein to be extracted and transported to a further processing facility and / or could be transportable itself. The apparatus 1 may also comprise a baling unit and storage system. The baling unit and / or the storage system can be integrated with or separate to the apparatus and can be of any suitable type as would be known to a skilled person.[000232] The apparatus 1 has a 15 supported by the vehicle body 11. In the embodiment described herein and best seen in Figure 6, the juicer 15 is a screw press 15. In alternative embodiments, the juicer 15 may be a hydraulic press, a mincer, or a blender, for example. A screw press is preferred. It is also possible for there to be a plurality of screw presses, with pulp material from the first press being fed into the second press. Screw presses may be either linear straight or conical. [000233] The screw press 15 has a hopper 17 configured to receive the plant material at one end, a solids discharge outlet 19 at the other end, with a juice outlet 21. The screw press 15 has a cylindrical screen 23 and a screw 25 rotatably mounted within the cylindrical screen 23. The screw 25 extends from the hopper 17 to the discharge outlet 19. The screw press 15 is configured to remove liquid from the plant material 7 to produce a protein containing plant juice. As the screw 25 rotates, the plant material 7 is carried along the length of the cylindrical screen 23 in a direction from the hopper 17 to the discharge outlet 19. The screw 25 forces the plant material 7 against the screen 23, which mechanically disrupts the plant material 7 and extracts the juice. The plant material 7 continues to travel along the cylindrical screen 23 as juice continues to be extracted from the plant material 7. When the plant material 7 has reached the discharge outlet 19, the pulp is discharged out of the solids discharge outlet 19. [000234] The screw press 15 (best seen in Figure 6) has a ram. The pressure of the ram is controlled by air pressure of 0 – 7 bar, resulting in 1.5 T to 9 T back pressure. This results in a dry matter extraction of 15% - 45% from the plant material 7 (such as alfalfa) into juice. The back pressure can be increased to 20T, preferably to between about 10T and about 15T, and run consistently at these pressure levels in the process of the invention which improves plant juice production rates. [000235] The apparatus 1 also has a dosing composition inlet 26. The inlet 26 is in fluid communication with a dosing mechanism 27 having an outlet 29 located at or near the juice outlet 21 configured to deliver a dosing composition to the juice downstream from the juice outlet 21. The dosing mechanism 27 can be, for example, a mechanism for in-line dosing. [000236] In the embodiment shown in Figure 6, the dosing composition inlet 26 is located near the juice outlet 21. The dosing composition inlet 26 is located about 100 mm to about 500 mm downstream from the juice outlet 21. In other embodiments, the dosing mechanism outlet 29 may be located about 1m, 1.5m, 2m, 2.5m or 3m downstream from the juice outlet 21. In other embodiments, the dosing mechanism outlet 29 may be located about 200mm, 300mm, or 400mm downstream from the juiceoutlet 21. In an alternative embodiment, the dosing mechanism outlet 29 may be located at the juice outlet 21. In a preferred the dosing mechanism outlet 29 may be positioned to allow the dosing composition to be added to the juice after cooling by the cooling system. In a further embodiment, the dosing composition may be added to the juice in the tank (as best seen in Figure 2), in which embodiment the tank may optionally include a suitable agitation system to circulate the dosage composition within the plant juice. [000237] The various locations of the dosing mechanism outlet 29 described above allow a dosing composition to be immediately added to the juice to mitigate or prevent further enzymatic activity and improve the stability of the plant juice. In this context, “immediately” refers to a time period of less than about 90 seconds, for example from about 90, about 80, about 70, about 60, about 50, about 40, or about 30 seconds, preferably about 20 seconds. [000238] With reference to Figure 7. The apparatus 1 has a control system 31 including a flow meter 33 to measure the flow of juice. The dosing mechanism 27 is configured to add the dosing composition to the juice based on the mass flow of juice measured. [000239] The apparatus 1 also has a cooling system configured to cool the juice that has been extracted from the plant material 7. The cooling system may be a refrigeration system 35. Alternatively, other systems processes or devices may be used for cooling the juice, such as air cooling, or water / ice that is colder than the juice. [000240] The refrigeration system 35 has a heat exchanger 37. In the embodiment shown, the heat exchanger 37 is a plate heat exchanger. It will be appreciated that the heat exchanger 37 may be any other suitable heat exchanger such as a shell in tube or tube in tube heat exchanger. [000241] The refrigeration system 35 has a refrigeration conduit 39 in fluid communication with a tank 41 and the heat exchanger 37. [000242] The apparatus 1 has a pump 43 configured to move the juice in the refrigeration conduit from the tank 41 towards the heater exchanger 37. The pressure provided by the pump 43 to the juice in the refrigeration conduit 39 also provides pressure to the juice recirculation line and the clean in place system. In alternative embodiments, the pump 43 may be located in one of the other conduits.[000243] The refrigeration system 35 has a valve 45 configured to receive juice from the heat exchanger 37 (via a conduit 44) and to deliver juice to the tank 41 and / or a clean in place system 47. [000244] The apparatus 1 also has a storage tank 41 in fluid communication with the plant juice outlet 21 downstream from the dosing mechanism 27. The tank 41 is a balance tank. If desired, the tank will preferably be configured to be capable of maintaining the temperature of its content within the desired range, such as through insulation, refrigeration, or both. For example, a connected refrigeration system, in which the control of temperature is governed by an electronic control unit incorporating a temperature measurement device, a cooling device, and a feedback programmable logic controller (PLC). The tank 41 has a juice inlet 49 that is in fluid communication with the juice outlet 21. Figure 5 shows two valves 51 between the juice outlet 21 and the tank 41. Each valve 51 has an inlet 53 in fluid communication with the juice outlet 21 and two outlets 55. One outlet 55 is in fluid communication with a dump and the other outlet 55 is in fluid communication with the tank 41. In an embodiment, the tank includes a dosing composition inlet and an agitation device. [000245] As seen in Figures 5 and 7, The apparatus 1 also has a juice recirculation system 57 in fluid communication with the storage tank 41 and downstream from the storage tank 41. The juice recirculation system 57 is configured to deliver a portion of the juice from the storage tank 41 back to the screw press 15. Surprisingly, this provides an improvement in the extraction of protein in the plant juice from the plant material and a higher protein concentration in the resulting juice stored in the storage tank 41. [000246] The juice recirculation system 57 has a juice recirculation conduit 59 in fluid communication with the tank and the screw press 15. [000247] The juice recirculation system 57 also has a valve 61 located intermediate the tank 41 and the screw press 15. The valve 61 is configured to control the flow of juice through the juice recirculation conduit 59. The valve 61 may be controlled manually or by the control system 31 which may be a PLC or electronic flow control system. The juice recirculation system 57 has a nozzle 63 configured to deliver the juice from the conduit 59 to the screw press 15. [000248] Temperature maintenance on the screw press 15 can be achieved by testing the temperature of the plant juice exiting the outlet 21 of the screw press 15 and then by adjusting the flow rate of the recirculated cooled plant juice into the screw press 15 or by adjusting the temperature that the plant juice is cooled to prior to recirculation,or a combination of both. Temperature control can, of course, be controlled via an automated feedback control system temperature sensor(s) and related flow / temperature controls as would be known to a person skilled in the art. [000249] As one of the uses of the pulp is as an animal feed, it is preferred that the juice recirculated into the plant material 7 does not contain dosing composition. Thus, in alternative embodiments, the portion of the juice to be recirculated into the plant material 7 is separated out for recirculation before dosing composition is added, and after cooling by the cooling system, to the remainder of the juice. This also serves to reduce the amount of dosing composition required to achieve the levels of dosing composition in the stored plant juice as dosing composition is not lost into the pulp produced. [000250] The clean in place system 47 has at least one nozzle 65 in fluid communication with the screw press 15. The clean in place system 47 also has at least one nozzle 65 in fluid communication with the tank. Figure 5 shows that each nozzle 65 is a spray ball. Each nozzle 65 is associated with a valve 67. The valves 67 are in fluid communication with a spray ball feed conduit 73. [000251] The clean in place system 47 has a clean in place valve 67 configured to receive juice from the clean in place cycle and to deliver juice to the tank 41 via a tank return 69 and / or the screw press 15. Examples Example 1 [000252] 6500 kg of alfalfa was cut 10cm above ground level and rowed using a front mower (CLASS, UK) mounted on a tractor (FENDT, Germany) before being picked up using a forage harvester (CLAAS, UK) fitted with knives which macerated the forage material down to 5mm sections before being blown into a chaser forage wagon (Giltrap, New Zealand). The forage wagon was then driven 15 minutes to the juicing site. The forage at ambient temperature (17 °C) was then fed via the side feed on the forage wagon onto a conveyor belt (HOME MADE, no brand) and fed through a hopper into the Vincent VP -16VT (Vincent Corporation, USA) and pressed within 30 seconds of entering the feed hopper. The cone pressure was set to 9 T using hydraulic ram pressure. [000253] Juice coming off the press was measured to be 18 °C using a PT100 thermometer as collected in a central storage tank from where juice is actively pumped through a filtering system and a refrigeration unit which chills the juice down to 6.5 °C. 4000 L juice was collected from the first extraction pass. The pressed forage material(pulp) was collected in a wagon (Giltrap, New Zealand) and measured to be 19 °C. Approximately 2500 kg pulp was load cells in the wagon. [000254] To commence the second pass, collected pulp material was driven back around to the conveyor and fed back into the hopper at approximately 89 kg / min (measured by reading off the wagon mass every 5 minutes). During the second pass, juice was redirected after it has been filtered and chilled to recirculate into the feed hopper and mixed with the incoming pulp material. The rate was determined by a calibrated dosing port located in the hopper and added at a rate of 5300L / h. Juice extracted from the second pass was measured to be 11.5 °C directly off the screw press. After the second press was completed, juice was pumped back into the central storage tank and continuously pumped through the refrigeration unit until all pressing was completed and final juice temperature was 5.5 °C. 4500 L of juice was collected from the second pass with 2000 kg of second pressed pulp material collected. All collected juice was unloaded into a storage vessel ready for transportation. During unload aqueous sodium metabisulfite was added to the juice in the storage vessel to provide a final concentration of 0.03% w / w. Juice was transported to the wet processing facility which was a 35 minute drive away. On arrival to the wet processing facility, juice temperature was measured to be 6 °C. Table 1: Characteristics of plant, pulp, and juice Item Fresh alfalfa Pulp Juice Dry Matter, % 14.94 16.85 6.5 Energy, Metabolizable energy %DM 10.7 10.76 - Crude Protein %DM 26.78 24.39 40.5 Sugars %DM 5.78 5.39 3.4 Table 2: Juice characteristics Dry Crude Ash Carbohydrates Fat Fructose Matter Protein %DM %DM %DM %DM %DM %Fresh Weight Juice 6.52% 40.49% 21.47% 33.74% 4.14% 3.37% Fructose Glucose Lactose Maltose Sucrose Total sugar %DM Juice 3.37% 0.00% 0.00% 0.00% 0.00% 3.37% Example 2[000255] Alfalfa was harvested using a lawn mower with a catcher (Stihl, Germany) with a cut height of 7cm. The fresh was deposited into a plastic bin and transported 30 min by car to the Leaft processing site. The harvested alfalfa was hand fed into a screw press (Vincent Corporations CP-4, USA) the cone pressure was set to 90 psi using an air ram. Juice (first press juice) was collected separately to the pulp material (first press pulp), both juice and pulp were weighed using floor scales (Mettler Toledo, Switzerland) and held at ambient temperatures (~20 °C). Juice (first press juice) was combined with pulp (first press pulp) at a 1:1 ratio w / w (pulp:juice), by pouring juice into the pulp container and mixing by hand until all of the juice was visually absorbed by the pulp.. The mixture of pulp and juice was then hand fed into the screw press. Again, juice (second press juice) was collected separately to pulp material (second press pulp). Upon complete of pressing 1st press pulp, 1st and 2nd press juice was combined and sodium metabisulfite was added to bring the final concentration in the combined juice to 0.2% w / w. Mass and compositional data was recorded for all generated pulp and juice samples. Table 3: Mass balance for extraction trial Item Mass (kg) Fresh Alfalfa 45.2 Juice (first press juice) 28.0 Pulp (first press pulp) 15.3 Pulp / juice mixture 30.6 Juice (second press juice) 19.6 Pulp (second press pulp) 11.0 Table 4: Composition of feed material and products of extraction Dry Crude Total Matter Protein protein %FW %DM %DM Alfalfa 16.23% 29.99% 11.30% Pulp 39.10% 19.50% 4.87% Juice 8.22% 36.86% 25.23% Example 3 [000256] In a similar process to Example 2, 20 kg of lucerne was cut using a lawn mower (Stihl, Germany) and pressed with screw press (Vincent Corporation, Florida USA) set to 67 mm back pressure. 1:1 juice to pulp w / w was added in to each subsequentpress after the 1st press, up to four All the juice was combined and sodium metabisulfite added to bring final in combined juice to 0.08% w / w. Samples were collected after each of 1st, 2nd, 3rd and 4th press and compared to a control sample prepared with 4 presses but no juice added. Table 5: Extraction ratios of wet mass, dry matter, and total protein from alfalfa into green juice Control 1st 2nd Total 3rd Total 4th Total % press press after press after press after increase 2nd 3rd 4th vs press press press control Fresh 56.37% 54.69% 36.05% 66.68% 22.88% 70.44% 70.09% 75.37% 33.70% weight Dry 33.59% 31.52% 16.76% 40.92% 22.37% 49.16% 26.83% 55.25% 64.49% matter Soluble 45.74% 49.75% 46.57% 73.15% 40.02% 82.52% -5.83% 81.94% 79.14% crude protein [000257] The results showed that pressing for three times increased extraction each time. After the fourth press some protein began to be lost back in to the pulp. This is likely due to the pulp remaining after the third press having components extracted to a limit such that no further protein can be extracted, instead the added juice over the fourth press is absorbed back into the pulp rather than working as an extraction aid to improve protein extraction. Example 4 [000258] 300 g lucerne was harvested and pressed through an Oscar DA1000 Press (Oscar, New Zealand) similarly to example 2. No liquid addition, juice addition, and water addition were tested to determine the component extraction yields and juice composition for each of the three treatments. For each treatment, the first press pulp was collected and weighed, and passed back through the press with the appropriate treatment applied for the second press (no addition, juice addition, or water addition). Where juice or water was added back into the pulp, the weight ratio was 1:1. [000259] In this comparative example, treatments with no addition, juice addition and water addition were compared using a single alfalfa feed crop. The alfalfa feed crop was determined, using crop physiological measurements, to be out of specification resulting in juice that would be considered out of specification for desired total protein. The extraction of this crop was consistent with extraction of in specification crop.[000260] The absolute and %dry matter compositions of the juices were measured by AOAC methods. Table 6: Mass balance, extraction ratios, and juice composition for each treatment Treatments No addition Juice Water addition addition Alfalfa Feed (g) 278.2 272.6 294.3 Juice / water added (g) 0 152.8 197 Pulp (g) 63.9 66.4 51.6 Juice (g) 189.1 182.2 401.1 Extraction % (w / w) Wet weight extracted 68.0% 66.8% 81.6% Dry matter extracted 36.6% 37.2% 48.2% Crude protein extracted 41.5% 45.1% 49.8% Total protein extracted 65.0% 76.0% 78.1% Juice composition (%Dry matter basis, w / w) Ash 14.1% 13.6% 12.8% Fat 6.8% 6.8% 3.7% NPN 1.7% 1.6% 1.5% Crude Protein 25.3% 27.0% 23.0% Total Protein 14.8% 17.0% 13.5% Carbohydrates 39.5% 36.6% 48.2% Total sugar 14.3% 16.0% 12.3% Total solids 8.7%% 9.0% 5.7% [000261] The use of a liquid medium (juice or water) during the second pass of plant material through the press resulted in a higher amount of protein extracted from the plant into juice compared with nothing added to aid extraction. The use of water resulted in slightly more protein extracted (78.1%) compared with juice as the extraction medium (76% extracted), however, more total dry matter was extracted using water compared to juice which is undesirable because it means downstream purification of the protein is more intensive. Further, due to water being added, the resulting juice more dilute (5.7% total solids) compared with when juice was added (9.0% total solids) which is undesirable because it increases equipment sizes required to process the juice, requires more energy to transport the same amount of absolute protein, and more energy to remove the water during downstream processing. Juice resulting from a juice-extracted plant material is better for an economic system and process.Example 5 [000262] Freshly harvested alfalfa (45 kg) was macerated on a Model CP-4 screw press (Vincent), separately collecting the first pass juice (28.0 kg) and pulp (15.3 kg). Pulp (4.7 kg) was combined with first pass juice (4.7 kg) which had been variously cooled to 4 degrees; or maintained at ambient (18.0 degrees); or warmed to 35 degrees and macerated for a second pass. Temperature, mass and compositional data was recorded for all so generated pulp and juice samples. Table 7: Temperature measurements in degrees Celsius. Input Input Combined Outcoming Outcoming forage / pulp juice forage pulp juice / juice First pass 13.6 - - 26.0 18.0 maceration of forage Second pass maceration of pulp Cooled 18.7 4.0 6.2 25.5 10.5 juice Ambient 18.7 18.0 18.3 34.2 17 juice Warm 18.7 35.0 33.0 37.5 20.3 juice [000263] Data shows that juice acts to cool the pulp during maceration and to lower the temperature of the outcoming juice. [000264] In the absence of juice recirculation maceration generates an increase in temperature of the outcoming pulp of typically 10 to 12 °C, although higher outcoming pulp temperatures may be generated at higher applied screw or maceration pressure, or if drier forage or pulp inputs are used, or during prolonged operation. [000265] In the absence of juice recirculation an increase in temperature of the outcoming juice is typically 5 degrees higher than the input forage. Recirculation of juice to the maceration stage moderates the increase in pulp temperature and moderates the increase in outcoming juice temperature. [000266] The temperature of the input forage, input pulp and the temperature of the juice, recirculated juice and outcoming juice can be measured and monitored using devices known to a skilled person including thermometers, thermocouples, infrared thermometers, thermistors, and bimetallic devices. The temperature monitoring and control may be manual, wireless, or connected to an electronic feedback loop. Thecontrols may be manual or automatic for control of juice flow, maceration speed or maceration pressure, temperature, and recording. Example 6 [000267] Juices were prepared according to Example 2. [000268] Method for PPO (Polyphenol Oxidase) assay: Heat treated juice at native pH was clarified by centrifugation at 10,000 rcf for 10 minutes, and then dosed with variable concentration of sodium metabisulfite (0, 250, 500, 800, 1500, 2000 ppm). 10 uL of these so prepared samples were mixed with 200 uL of 100 uM catechol reagent and incubated at 4 degrees, or at 21 degrees. Visual recording of colouration was recorded at various time points. After 2 hours there was noticeable browning in the test samples held at room temperature with sodium metabisulfite concentrations less than <1500 ppm metabisulfite. In contrast minimal browning was observed samples cooled to 4 degrees, with no browning observed above 250 ppm. [000269] After 5 days, samples held at 21 degrees were intensely coloured for all metabisulfite dosing concentrations whereas those maintained at 4 degrees were only noticeably coloured below 800 ppm indicating a favourable stabilisation of the sodium metabisulfite dosing agent at lower temperatures. Table 8: Relative visual colour intensity Sulfite 4 deg 21 deg 4 deg (5 days) 21 deg (5 days) concentration (ppm) 0 + ++++ ++++++ ++++++ 250 + +++ +++++ ++++++ 500 - ++ +++++ ++++++ 800 - + + ++++++ 1500 - + - ++++++ 2000 - - - ++++++ [000270] It is not the intention to limit the scope of the invention to the abovementioned examples only. As would be appreciated by a skilled person in the art, many variations are possible without departing from the scope of the invention as set out in the appended claims.

Claims

CLAIMS 1. A process for producing a plant juice comprising protein from a harvested plant material, the process comprising steps of: a) extracting plant juice from the harvested plant material; b) cooling the extracted plant juice; c) recirculating a portion of the cooled extracted plant juice from step (b) into the extraction step (a); and d) adding a dosing composition to the extracted plant juice to produce the plant juice comprising protein.

2. The process of claim 1, wherein the harvested plant material has been harvested as a whole plant or part of a plant.

3. The process of claim 1 or claim 2, wherein the plant material is selected from any one or more of the family Fabaceae; the family Gramineae; the family Lemnoideae; from the family Brassicaceae; or the family Amaranthaceae.

4. The process of claim 3, wherein the plant material comprises leaf material selected from any one or more of alfalfa, kudzu, forage peas, oats, spinach, kale, roadside crops, cocksfoot, Italian ryegrass, Raphno®(kale-radish hybrid), clover, Persian clover, rapeseed, carrot, radish, Jerusalem artichoke, beet, spinach, fodder beet; triticale, white clover, barley, tobacco, chicory, sugar cane, or fava bean.

5. The process of claim 3, wherein the plant material comprises leaf material from duckweed.

6. The process of any one of claims 1 to 4, wherein the harvested plant material has been harvested as a whole plant and wherein the plant has been cut at a height of between about 7cm and about 20cm above the ground.

7. The process of any one of the previous claims, wherein the plant juice is extracted from the plant material using at least one maceration device.

8. The process of claim 7 wherein the maceration device is selected from any one or more of a screw press; a hydraulic press; a mincer; or a blender.

9. The process of any one of claims 6 to 8, wherein the maceration device is a screw press or a plurality of screw presses.

10. The process of claim 9, wherein the screw press or a plurality of screw presses have between about 1.5T and 20T back pressure and wherein the back pressures of the plurality of screw presses can be the same or different.

11. The process of claim 9 or claim 10, wherein the screw press or any one of the plurality of screw presses comprises a twin screw press.

12. The process of any one of the previous claims, wherein the extracted plant juice in step (b) is cooled to a temperature of below about 12°C.

13. The process of any one of the previous claims, wherein the cooling of the extracted plant juice in step (b) commences within about 5 minutes of extraction.

14. The process of any one of the previous claims, wherein the portion of the cooled plant juice recirculated in step (c) is taken from the cooled plant juice before the dosing composition of step (d) is added.

15. The process of any one of the previous claims, wherein the portion of the cooled plant juice recirculated in step (c) is added with the harvested plant material as it enters extraction step (a).

16. The process of any one of the previous claims, wherein the ratio of the cooled plant juice recirculated in step (c) to the harvested plant material in the extraction step (a) is in the range of 2:1 to 1:2 (wt / wt).

17. The process of any one of the previous claims, wherein the temperature in step (a) is controlled such that the plant juice extracted from step (a) is below about 20ºC using the recirculated portion of the cooled extracted plant juice in step (c).

18. The process of claim 17, wherein the temperature in step (a) is controlled such that the plant juice extracted from step (a) is below about 15ºC.

19. The process of any one of the previous claims, wherein the plant juice comprising protein produced by the process is stored a temperature of below about 12°C.

20. The process of any one of the claims, wherein the plant juice comprising protein produced by the process is stored in a refrigerated container.

21. The process of any one of the previous claims, wherein the time between extracting the plant juice from the harvested plant material and commencing cooling the extracted plant juice in step (b) is between about 3 and about 15 minutes.

22. The process of any one of the previous claims, wherein the time between harvesting the plant material and commencing cooling the extracted plant juice in step (b) is less than about 3 hours.

23. The process of any one of the previous claims, wherein the dosing composition comprises any one of more of: a reducing agent, a chelating agent, a pH modifying agent, mono, divalent or trivalent metal ions, a precipitant, minerals, a filter aid, or a modifying buffer or co-solvent.

24. The process of claim 23, wherein the dosing composition comprises a reducing agent selected from ascorbic acid, citric acid, oxalic acid, cysteine, dithiothreitol (DTT), dithioerythritol (DTE), tris(2-carboxyethyl)phosphine (TCEP), β- mercaptoethanol (BME), sodium dithionate, nitrilotriacetic acid (NTA), Cysteamine, Glutathione (GSH) and / or metabisulfite.

25. The process of claim 23 or 24, wherein the dosing composition comprises aqueous sodium metabisulfite.

26. The process according to any one of the previous claims, wherein the dosing composition is added in step (d) in an amount sufficient to result in a concentration of the dosing composition in the plant juice comprising protein produced by the process of from about 0.005% to 2.0% (w / v).

27. The process according to claim 24, wherein the dosing composition is added in an amount sufficient to result in a concentration of the dosing composition in the plant juice comprising protein produced by the process of less than 0.03% (w / v).

28. The process according to any one of the previous claims, wherein the dosing composition is added as a fixed dose to the extracted plant juice in step (d).

29. The process according to any one of previous claims, wherein the plant juice comprising protein produced by the process is stored and comprises: a) a protein content of between about 5-50% on a dry weight basis, b) a temperature of less than about 12°C, and wherein the plant juice is stable for at least 4 hours.

30. The process of claim 29, wherein the plant juice comprises a protein content of between about 10-35% on a dry weight basis, and a total carbohydrate content of between 15-40% on a dry weight basis.

31. A process for producing a plant juice comprising a protein content of between about 5-50% on a dry weight basis from a harvested plant material, the process comprising steps of: a) harvesting the plant material as a whole plant; b) passing the plant material of step (a) through a screw press to extract plant juice from the harvested plant material; c) cooling the extracted plant juice to a temperature of below about 12C; d) recirculating a portion of the cooled extracted plant juice from step (c) into the screw press with the plant material; and e) adding sodium metabisulfite to the cooled extracted plant juice after steps (c) and (d) to produce the plant juice; and wherein the temperature in the screw press in step (b) is controlled so that the temperature of the extracted plant juice from step (b) is below about 20ºC via the recirculation in step (d), and wherein the time between passing the plant material through the screw press in step (b) and commencing cooling of the extracted plant juice in step (c) is between about 3 and about 15 minutes.

32. A plant juice extracted from a plant material, wherein the plant juice: a. comprises a protein content of between about 5-50% on a dry weight basis, b. has a temperature of less than about 12°C, and c. is stable for at least 4 hours.

33. The plant juice of claim 32, wherein the plant juice comprises a protein content of between about 10-35% on a dry weight basis, and a total carbohydrate content ofbetween 15-40% on a dry weight basis.

34. The plant juice of claim 32 or 33, wherein the plant juice comprises sodium metabisulfite in an amount of between about 0.005% to 2.0% (w / v).

35. The plant juice of any one of claims 32 to 34, wherein the plant juice comprises a polyphenolic content of less than about 6%.

36. The plant juice of any one of claims 32 to 35, wherein the plant juice has a temperature of about 4°C, and a microbial load of less than about 1,000,000cfu / ml after about 9 hours.

37. The plant juice of any one of claims 32 to 36, wherein the plant juice has a temperature of about 4°C, and a microbial load of less than about 600,000cfu / ml after about 4 hours.

38. A stable plant juice extracted from a plant material, wherein the plant juice: a. comprises a protein content of between about 5-50% on a dry weight basis, b. has a temperature of below 5°C, c. sodium metabisulfite in an amount of less than 0.03% w / v d. a polyphenolic content of less than about 6% w / w, and e. has a microbial load of less than about 600,000cfu / ml after about 4 hours.

39. An apparatus for producing a plant juice comprising protein from a plant material, the apparatus comprising: (i) a juicer configured to extract liquid from plant material to produce a juice, the juicer having an inlet to receive plant material and a juice outlet for the plant juice that has been extracted from the plant material; (ii) a cooling system configured to cool the juice that has been extracted from the plant material; (iii) a juice recirculation system configured to receive a portion of cooled juice from a location at or near the juice outlet downstream of the cooling system and deliver the portion of cooled juice to the juicer; (iv) optionally a storage tank fluidly connected to the juice outlet, the storage tank being configured to maintain the juice at the cooled temperature; and (v) a dosing mechanism configured to deliver a dosing composition to the juicedownstream from the juice outlet.

40. The apparatus of claim 39, wherein the juicer is selected from any one or more of a screw press, a hydraulic press; a mincer; or a blender.

41. The apparatus of claim 39 or 40, wherein the cooling system comprises a heat exchanger.

42. The apparatus of claim 41, wherein the heat exchanger comprises a plate heat exchanger.

43. The apparatus of claim 41 or 42, wherein the cooling system comprises a refrigeration system comprising a refrigeration conduit in fluid communication with the storage tank and the heat exchanger.

44. The apparatus of claim 43, wherein the refrigeration system comprises a pump configured to move the juice in the refrigeration conduit from the storage tank towards the heat exchanger.

45. The apparatus of any one of claims 35 to 44, wherein the cooling system cools the plant juice within about 5 minutes of extraction from the plant material.

46. The apparatus of any one of claims 35 to 45, wherein the cooling system cools the plant juice to a temperature of less than about 12°C.

47. The apparatus of any one of claims 35 to 46, wherein the juice recirculation system receives a portion of cooled juice from upstream of the dosing mechanism to the juicer.

48. The apparatus of any one of claims 35 to 47 wherein the juice recirculation system is configured to deliver a portion of the cooled juice to the inlet of the juicer.

49. The apparatus of claim 35, wherein the apparatus comprises a storage tank fluidly connected to the juice outlet and the dosing mechanism comprises a dosing composition inlet connected to the storage tank, and wherein the storage tank optionally comprises an agitation device configured to mix the dosing composition with the plant juice.

50. The apparatus of any one of claims 49, wherein the apparatus comprises a storage tank fluidly connected to the juice outlet, the storage tank being capable to maintain the temperature of the plant juice in the storage tank at a temperature of less than about 12°C.

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