Food or edible material: processes – compositions – and products – Products per se – or processes of preparing or treating... – Protein – amino acid – or yeast containing
Reexamination Certificate
2001-08-31
2004-10-05
Weier, Anthony (Department: 1761)
Food or edible material: processes, compositions, and products
Products per se, or processes of preparing or treating...
Protein, amino acid, or yeast containing
C162S024000, C162S091000, C162S097000, C162S098000, C099S537000
Reexamination Certificate
active
06800319
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to the separation and recovery of components from vegetable raw materials.
Plants, like most organisms, are made up of cells. A plant cell consists of a Lipid membrane with a generally aqueous content, the cytosol, which contains the various cell organelles (likewise surrounded by lipid membranes), such as nucleus, mitochondria, endoplasmic reticulum and chloroplasts, and the cytoskeleton, made up of microfilaments and microtubules, which gives the cell an inner structure. Also present in the plant cell are vacuoles which play an important role in keeping the plant cell under tension; the vacuoles maintain the turgor of the cell.
The constituent components of a plant cell can be roughly distinguished into water, which accounts for the greater part by far of a living cell, components such as salts, (precursors of) lipids, carbohydrates, amino acids and nucleotides, macromolecules such as starches, proteins and nucleic acid and a multiplicity of other molecules, including vitamins and pigments such as chlorophyll, carotene and xanthophyll.
A plant cell is generally surrounded by a cell wall which provides firmness and structure to the plant tissue. The cell wall is mainly built up from (hemi)cellulose and other carbohydrate polymers, which have aggregated to fibers. Woody plants further contain an ample amount of lignin, a polymer made up of phenols and other aromatic monomers.
Plant tissue is made up of plant cells, all of which, when living, basically satisfy the above description. An important distinction can be made between relatively firm tissues which comprise virtually no chloroplast or other plastid containing cells, and the relatively soft tissues which generally do. Tissues which generally comprise no chloroplast containing cells are, for instance, the epidermis or skin tissue of a plant, the collenchyma and sclerenchyma or stroma of a plant and the vascular fiber bundles or the vascular tissue, comprising the important transport vessels (wood vessels and sieve tubes) in the plant. When a part of a plant is strongly lignified, in general, over time, the majority of the cells in the lignified part die off and only residues of the cell content are left. In particular the cytosol and the organelles present therein are lost, but the vascular fiber bundles, skin and stromas generally give the plant form and structure and generally remain present when the plant is dead. Characteristically, these relatively firm tissues (in particular vascular bundles, sclerenchyma and epidermis) comprise no to virtually no chloroplast containing cells, while an important part (at least in the aerial leaf and stem parts of the plant) of the relatively soft tissues, also called chlorenchyma, is made up chiefly of only chloroplast-containing parenchymal cells; indeed, this is where photosynthesis occurs.
It has long been known to recover various components from vegetable raw materials for further use in, for instance, food for human or feed for animal consumption through mechanical methods. Often, plants are merely comminuted or chopped to make them suitable for consumption, an example being the chopping of maize for feed.
However, in particular the components present in the plant cell cytosol are outstandingly suitable for human food or animal feed, since these can be building materials for corresponding components which are found in animal cells.
Mechanical processing is applied, for instance, to feed crops, such as grass, lucerne and other fresh and green harvested plants which, often as virtually whole plant, in particular the leaf and/or stem parts and in most cases not including the roots, are used for recovering, for instance, (animal) feed components. Such vegetable raw materials are generally recovered through pressing of (preferably chopped or otherwise comminuted) leaf and/or stem material, whereby a part of the vegetable material is obtained as press juice, while the residual and pressed material is known as press cake.
The pressure forces exerted by pressing generally result in the opening up (snapping or bursting) of plant cells in the material, so that the aqueous but food component-rich cytosol, possibly with residues of the organelles and the lipid membrane surrounding the cell, is liberated from the cell as press juice. Press juice is generally treated further, for instance through screening, whereafter, for instance, the protein in the juice is recovered by means of coagulation through, for instance, acid and/or heat treatment. Press juice may also be further processed through (ultra or membrane) filtration, drying, fermentation or other methods known to the skilled person. Protein-rich or otherwise high-grade nutrients for human and animal consumption, but also pigments such as carotene (provitamin A), can be recovered from cytosol in this way.
The resultant, relatively dry press cake is generally considered to be less rich in food; it contains relatively intact fiber bundles composed of (not directly) digestible cellulose fibers, adherent press juice and residual plant cells which have not been accessed under the influence of the pressing. Especially these residual plant cells with unrecovered cytosol give fodder value to the press cake, which is generally dried and, pelleted or otherwise, is used as relatively low-grade roughage component in fodders, in particular for ruminants.
For mechanically accessing, for instance, lucerne or grasses, traditionally a method is used which is based on the disintegration of the vegetable raw material by means of hammer mills followed by squeezing the disintegrated raw material (here designated as pulp) using screw presses or belt presses. The pulp is thereby separated into a press cake fraction and a press juice fraction. The juice fraction is regarded as the fraction in which the industrially recoverable content substances from the plant material are contained. Hammer mills typically consist of a rotor on which fixed of freely movable elements are disposed which upon rotation of the rotor are brought into contact with the vegetable raw material and disintegrate it through force of impact. The disintegratory effect of hammer mills is relatively large when the vegetable material has a good turgor, i.e. when the plant cells are under tension. In that case, the force of impact causes the tissue to snap and causes the cell content constituents to be liberated with the tissue fluid. If turgor is low, beating the plant material will cause it to be compressed. The tissue then remains more or less intact and the result is that the cell content becomes available to a much lesser extent. This has major consequences for the recoverability of particularly those cell content constituents that are present in the vegetable biomass only partly in dissolved form and for another part in the form of solid, undissolved matter. This holds true inter alia for vegetable proteins, but also for lipids and pigments. Also known (for instance from U.S. Pat. No. 5,464,160) are hammer mills where relatively dry material is separated into two fractions, this while neglecting the so valuable juice stream with protein-rich cytosol. Accordingly, these types of mills are not suitable for processing fresh, relatively wet material and eventually produce a relatively wet fiber fraction.
In the above-described methods of pressing vegetable material which contains at least leaf and/or stem parts, it is generally of importance that the material be processed while still as fresh as possible, shortly after harvesting. Only then are the plant cells sufficiently under tension to be able to burst or snap under pressure so that the cytosol is liberated. When, after harvesting, already some time has elapsed before the plant parts are pressed, they are already dried out to some extent by then, the plant cells present have lost a large part of the necessary turgor and are too slack to be able to snap or burst under pressure. Accordingly, in non-fresh material, the recovery of press juice will proceed with less efficiency. The same holds
Hulst Anne Coenraad
Ketelaars Jan Josef M. H.
Sanders Johan Pieter M.
Cooperatieve Verkoop-en Productievereniging van Aardappelmeel en
Hoffmann & Baron , LLP
Weier Anthony
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