IE43443B1

IE43443B1 - Vegetable matter treatment

Info

Publication number: IE43443B1
Application number: IE2388/75A
Authority: IE
Original assignee: Agro Proteine Ind
Priority date: 1974-11-04
Filing date: 1975-11-03
Publication date: 1981-02-25
Also published as: NZ179129A; AR212860A1; FR2294648B1; NL7512820A; RO85445B; ZA756775B; NL165040C; FR2294648A1; IN141168B; AU502317B2; RO85445A; DK493775A; CA1066116A; ES442296A1; OA05158A; IE43443L; NL165040B; PL96637B1; HU174437B; AU8627775A

Abstract

1528783 Extracting protein from leafy vegetable matter FRANCE LUZERNE 30 Oct 1975 [4 Nov 1974] 44959/75 Heading C3H A cyclic process for treating leafy green vegetable matter (e.g. alfalfa) to recover separately the insoluble (protein) and liquid matter in cake and syrup form comprises (1) mixing a first quantity of the leafy matter with a predetermined quantity of a reheated previously produced serum, the quantity of serum being sufficiently large relative to the amount of leafy matter to provide a liquid treatment medium for the leafy matter, the temperature of the serum being sufficiently high to flocculate the protein content, the duration of contact with the serum being sufficiently long to macerate the leafy matter, (2) separating a sufficient proportion of the serum from the macerated leafy matter to form a cake having a dry solids content of 35-60 wt. per cent and at least one serum effluent; (3) drying the cake; (4) reheating at least a part of the serum effluent to at least the protein flocculating and macerating temperature; (5) recycling the reheated serum to a succeeding quantity of the leafy at the above-stated temperature and in the above-stated amounts to start a further cycle of the process and (6) concentrating the remaining part of the serum effluent to syrup viscosity.

Description

The inventioh relates to the treatment of green leafy plants, such as alfalfa, in order to realize an economy of heat during dehydration on the one hand, and to recover the proteins contained in the pressing juices on the other.

It is known that leafy green plants, used for animal feeding can be subjected to a dehydration and conditioning treatment making it possible to Obtain a feed material in the form of cylindrical granules or pellets which are easier to conserve and which transport and possess predetermined characteristics. In this respect, alfalfa is a vegetable matter particularly suited to animal feeding in its dehydrated form.

Processes are also known permitting the recovery of proteins from plants, such as alfalfa, by physicochemical treatments of the juice obtained by the pressing of crude vegetable matter.

It is very important to reduce as much as possible the consumption of heat necessary for the dehydration. Present day dehydration processes, for alfalfa for instance, consume large amounts of fuel, such as fuel oil, which is a costly raw material.

It has now been found that pressing vegetable matter makes it possible to extract a juice and obtain a pressed vegetable cake having a moisture content -243443 substantially lower than the initial moisture content of the raw material.

Under these conditions, dehydration of the cake becomes possible under thermal conditions which are particularly advantageous from the economical standpoint.

In another connection, the pressing juice more often than not has a high protein content the possible loss of which cannot be discounted. It is therefore desirable to recover the proteins contained in said juice by any suitable technical means.

The object of the invention is, therefore, a process for the treatment of leafy green plants, especially fresh alfalfa, making it possible to simultaneously attain the following objectives: (1) partial high level extraction of the initial moisture from the raw material, (2) excellent thermal economy during dehydration of the press cake; and (3) extraction of plant proteins from the pressing juice, said proteins being utilizable in animal and human nutrition.

The present invention provides a process for the treatment of leafy green vegetable matter, comprising the steps of: (1) mixing a first quantity of said leafy matter with a predetermined quantity of reheated previously produced serum of said leafy matter, the quantity of said serum being sufficiently large relative to the amount of leafy matter to provide a liquid treatment medium for said leafy matter, the temperature of said serum being sufficiently high to flocculate the protein content of said leafy matter, the duration of contact of said leafy matter with said serum being sufficiently long to macerate said leafy matter; (2) separating a sufficient proportion of said serum from said macerated leafy matter to form a cake,having a dry solids content of 35% to 60% by weight,and at least one batch of serum; (3) drying said cake; (4) reheating a part of said serum to at least said protein flocculating and macerating temperature; (5) recycling said reheated serum to a succeeding quantity of said -33443 leafy matter at the above stated temperature and in the above stated amount,to start a further cycle of said process; and (6) concentrating the remaining part of said serum to syrup viscosity.

We draw attention to the specification of our contemporaneous Patent.Specification Mo. 43202 which is also concerned with a process for treating leafy green vegetable matter.

According to the invention, the recycled serum obtained from pressing is subjected to reheating to raise its temperature to a value capable of ensuring flocculation of the protein substances in step (1) of the process of the invention. By means of this process, flocculation of the chloroplastic and cytoplasmic proteins is effected inside the plant cells, as well as flocculation of the proteins in the serum obtained from pressing. Furthermore, by means of said preliminary thermal treatment in step (1), the proteins in the juice released by shredding and by the injury to plant tissues are also flocculated, said juice being already mixed in the mass of the cut i.e, harvested vegetable matter. Before step (1), the fresh vegetable matter may be subjected to mechanical disintegration in a dilacerating apparatus (causing tissue tearing) or in an apparatus of the hammer crusher type (causing tissue rupture). Said step is in no way compulsory however, and it may even be preferable and more economical to avoid this practice when putting the invention into effect, as then the leaves are in original leaf form when they are mixed with the reycycled serum.

In the case of alfalfa, preheating of the serum is advantageously calculated to obtain a serum-green alfalfa mixture having a mean homogeneous temnerature of 80° to 100°C for the entire duration of the treatment of step (1).

For this purpose, the serum collected at the outlet of the press is pumped away and reheated by any known means, for example by passing it through a heat exchanger supplied with steam. The serum thus heated to from 80° to 100°C is partly recycled to the fresh alfalfa at the input of a suitable mixing apparatus. Alternatively, only that part of the serum which is recycled is -44 3 4 4 3 reheated, and the remainder of the serum is sent to the concentration step.

Any suitable conveyor-mixer devices capable of ensuring an intimate contact between the fresh vegetable matter and the serum recycled from pressing can be used in the process. One suitable device is a double screw conveyor-mixer in which the reheated serum is introduced adjacent to the input of vegetable matter.

For a serum having a temperature of about 85°C, the residence time of the alfalfa in the mixer is conveniently in the range of from 5 to 8 minutes. A man skilled in the art will easily determine the parameters of mixing taking into account the pecularities of the apparatus used and the vegetable matter treated, in order to obtain at the outlet of the apparatus a product wherein the serum is distributed in a uniform manner and the temeprature between the mass of solids and the serum in the product is balanced.

In the case of alfalfa, advantageous conditions for the macerationdiffusion step, associated with the flocculation of precipitable proteins within the plant cells are as follows: - temperature of the serum-fresh alfalfa mixture: 80° to 90°C, preferably 85° to 90°C, - use of 3 to 6 parts by weight of serum for each part by weight fresh alfalfa, - adjustment of the pH to a value of 5 to 6. - residence time: 5 to 8 minutes.

As has been stated above, flocculation of proteins is effected in the mixing step (1). The protein coagulum formed in the vegetable matter juice results in the formation of serum which will subsequently be extracted in the press. Advantageously a continuous high efficiency press of the type WHEEL PRESS, such as those built by the firms DAVENPORT PRESS and RIETZ is used to separate off the serum from the macerated leafy matter. These presses consist of two wheels the axes of rotation of which are inclined to the horizontal. The two wheels thus form a V permitting alfalfa to be supplied to the open portion of the V and pressing and extraction of serum -5in the closed part of the V. It is also possible to use a high yield continuous screw press, for example, the STORD or SPEICHIM types. At the outlet of the press there is obtained: - a cake weighing 5.0% to 40% of the initial weight of the fresh alfalfa used, said cake having a solids content (i.e. solids content on a dry solids base) of the order of 35 to 48%. - a serum weighing 50% to 60% of the initial weight of the fresh alfalfa used, said serum having a solids content of the order of 10 to 5%.

The cake can be dehydrated and then pelletized in a press to form pellets, by known techniques.

The serum obtained is partially recycled to treatment step (1) with preheating at from 80° to 100°C for heating the fresh alfalfa.

The remaining part of the serum may be concentrated in a triple or quadruple effect apparatus to obtain a concentrated serum or syrup having a solids content of the order of 50% to 65%.

The serum obtained at the outlet of the press can be subjected, in a knovzn manner, to further treatments making it possible to extract therefrom the proteins, which constitute valuable products as additives to animal and human nutrients.

In the case of alfalfa cake dehydration, the preheating of the recycled serum contributes to the supply of heat necessary for the final dehydration of the cake in the dryer after the pressing thereof.

The process of the invention will now be illustrated with reference to the accompanying drawing which shows the main steps of the process and the circulation of materials.

The leafy green vegetable material is introduced into a thermal treatment apparatus, operating with a wet medium, in the presence of a certain amount of recycled serum. The temperature in this first step of the process is conveniently of the order of from 80° to 90°C. The hot green leafy vegetable matter is then subjected to pressing to provide a serum and a cake. The cake (solids content: 35% to 48% average content) then undergoes dehydration by conventional means. A dehydrated green leafy vegetable matter flour is thus -64 3 14 3 obtained which is converted into dehydrated pellets in a conventional pelleting press.

The serum is partly recycled after reheating, for example at from 80° to 1OO°C. The amount of serum recycled depends solely on the heat requirements in the thermal treatment apparatus, taking into account the amount of green leafy vegetable matter to be treated and the temperature to be attained. The weight of recycled serum introduced is generally approximately three times the weight of the vegetable matter to be treated in the case of alfalfa. The remaining serum, which constitutes the larger part, is subjected to a concentration step providing a syrup with solids content in the range of 50 to 65%.

However, in the case of fresh vegetable matter with a high initial moisture content, such as alfalfa, the amount of serum recycled relative to the amount of vegetable matter to be treated i.e. the serum recycling coefficient, can be limited by supplying calories directly to step (1), for example by immersing a coil with a hot fluid, such as steam, flowing through it in the treatment medium. The mixture is in this instance heated by indirect means, and at least a part of the reheating of the serum occurs while the serum is being mixed with the leafy matter.

As a man skilled in the art will immediately understand, the process of the invention can easily be put into effect in a continuous manner.

EXAMPLE The invention is illustrated by the following example: 600 kg of serum (previously obtained) heated to a temperature of 95°-100°C is added to 100 kg of green alfalfa having a solids content of 20,7%, of which 16.80% is protein. The mixture rapidly reaches a temperature of 85°C. The mixture is maintained at this temperature for 8 minutes.

The hot alfalfa is pressed after draining. Pressing yields on the one hand, 42.5 kg of cake comprising 40% solids with a protein content of 17.70% and, on the other, 101.5 kg of serum comprising 6.2% solids and containing 13.00% total nitrogenous matter as well as 556 kg of juice (i.e. serum obtained by draining the macerated alfalfa comprising 4.70% solids and containing 12.20% total nitrogenous matter. -743443 The serum obtained by draining is combined with the serum obtained by pressing and 600 kg of the mixture is recycled to the fresh green alfalfa and the remaining 57.5 kg is concentrated, providing a syrup having a solids content of 50% to 60%.

The cake is dehydrated and pelletized to yield 18.9 kg pellets with 11% moisture content.

The amount of water evaporated in the dryer is 23.6 kg.

Claims

CLAIMS 1. (1) mixing a first quantity of said leafy matter with a predetermined 5 quantity of reheated previously produced serum of said leafy matter, the quantity of said serum being sufficiently large relative to the amount of leafy matter to provide a liquid treatment medium for said leafy matter, the temperature of said serum being sufficiently high to flocculate the protein content of said leafy matter, the duration of contact of said leafy matter 10 with said serum being sufficiently long to macerate said leafy matter;

1. A cyclic process for treating leafy green vegetable matter to recover separately the insoluble solid and the liquid matter therein in cake and syrup form, respectively, which comprise:

2. A process as claimed in claim 1 wherein said leafy vegetable matter is in natural leaf form when mixed with said recycled serum. (2) separating a sufficient proportion of said serum from said macerated 1eafy matter to form a cake, havi ng a dry soli ds content of 35% to 60% by weight, and at least one batch of serum;

3. A process as claimed in claim 1 or claim 2 wherein said vegetable matter 25 is alfalfa. (3) drying said cake; 15

4. A process as claimed in any of claims 1 to 3 wherein the weight of recycled serum is from 3 to 6 times the weight of the vegetable matter to which it is added. 5. A process as claimed in any of claims 1 to 4 wherein the recycled serum 30 has a pH of from 5 to 6 when mixed with said vegetable matter. -934 4 3 6. A process as claimed in any of claims 1 to 5 wherein the duration of contact is 5 to 8 minutes. 7. A process as claimed in any of claims 1 to 6 wherein the leafy matter is pressed until it has a solids content of 35% to 48% by weight. 8. A process as claimed in any of claims 1 to 7 wherein the remaining part of said serum is concentrated immediately after separation from said macerated vegetable matter. 9. A process as claimed in any of claims 1 to 8 wherein the part of said serum which is recycled is reheated to a temperature in the range of 80° to 100°C. 10. A process as claimed in claim 9 wherein at least a part of said reheating occurs during mixing of said serum with said leafy matter. 11. A process as claimed in any of claims 1 to 10 wherein the quantity and temperature of the serum which is recycled is such that the mixture of leafy matter and serum during said maceration has a temperature in the range of 80°C 12. A process as claimed in any of claims 1 to 11 wherein that part of the serum which is concentrated is concentrated to a solids content of 50% to 65% by weight. 13. A process as claimed in any of claims 1 to 12 wherein the dried cake is pelletized. 14. A leafy green vegetable matter press cake when produced by a process according to any of claims 1 to 13. 15. A leafy green vegetable matter serum when produced by a process according to any of claims 1 to 13. 16. A leafy green vegetable matter syrup when produced by a process according to any of claims 1 to 13. 17. An animal and human food which includes a press cake according to claim 14 as a supplementary nutrient. 18. An animal and human food which includes a syrup according to claim 16 as a supplementary nutrient. 19. A process for the treatment of leafy green vegetable matter substantially -104-3443 as described hereinbefore with particular reference to the accompanying drawing. 20. A process for the treatment of leafy green vegetable matter substantially as described hereinbefore with particular reference to the Example. 21. A product obtained from a process for the treatment of leafy green vegetable (4) reheating a part of said serum to at least said protein flocculating and macerating temperature; (5) recycling said reheated serum to a succeeding quantity of said leafy matter at the above-stated temperature and in the above-stated amount, to start a further cycle of said process; and 20 (6) concentrating the remaining part of said serum to syrup viscosity.

5. Matter substantially as described hereinbefore with reference to the Example and/or the accompanying drawing.