GB2054343A - Preserving green vegetable matter - Google Patents

Abstract

Green vegetable matter is crushed and then coagulated at 90- 100 DEG C for 2-4 minutes and thereafter dewatered by mechanical means, e.g. vibration, compression, vacuum filtration or centrifuging. Treatments of red clover, Medicage sativa and Torous dactylis are exemplified.

Description

SPECIFICATION Process for the preservation of green vegetable matter The invention relates to a process for the preservation of green vegetable matter of protein content, in the course of which the harvested plant is smashed to pieces and coagulated at 40-1000C temperature, then it is dewatered until the balance of water content is reached.

Preservation of the green vegetable matter of high protein content for the purpose of feeding at minimal loss, is one of the existing problems of the agriculture even today. The essence of most of the known processes is that the wate r content of the green vegetable basic material is reduced to the balance of water content (to about 12-18%) by removal of the water finally in the form of vapour. Its simplest method is drying in the sun taking place at low temperature without the input of extra energy, but it has its drawback in that despite the evaporation at this low temperature also the protein passes off with the water vapour, the possibility of the shedding of leaves increases involving loss of protein, the carotene decomposes and the quantity of the endproduct is reduced.

If the chopped vegetable matter is dried with flue-gas at high temperature, then the water passes out of the vegetable matter in the form of hot vapour, and the protein remains in the dry fibrous material because it got baked to be solid with the fluegas of high temperature (partially caramelized). The drawback of this rough process is that a considerable proportion of the vitamins is destroyed, the protein content and digestibility of the end-product are reduced. Further drawback is the high energy utilization, reduced yield, environment pollution and the fire hazard, as well as the fact that the trace-elements of the fuel (e.g. oil) and flue-gases may be found in the end-product.

Such process is already known whereby (see No.

H 1814 Hungarian disclosure document) the intercellular and cell water is removed in such a way, that the fodder is smashed to pieces extending at least to a certain part of the cells and with the use of compression the capillary and osmotic stresses in the smashed fibres are eliminated. This is followed by drying ofthe fodder to minimum 12% moisture content.

The fundamental drawback of this process is, that only that part of the nutritive materials in the green plant is utilized which remains in the pressed out fibrous product. Since however the pressing takes place at relatively high pressure (40-250 kg/cm2), valuable nutritive materials pass off with the water.

Regarding the loss of inner substance - arising during the process described in No. H 1814 disclosure document -- it is characteristic that in the processes according to the Hungarian patent specifications Nos. 153,249 and 152,580 exactly these nutritive materials in the press-juice are utilized. These processes are used for the production of the biologically fully valuable detoxified concentrate of increased protein content. Their substance is that the chopped vegetable matter is compressed, enriched with water, then compressed again and the filtered press-juice is condensed with vacuum evaporation.

After the addition ofanitoxidantthe protein fraction is mechanically separated and finally the material is dried with the use of heat. The drawback of these processes is that complicated machines are required and their productivity is lower than that of the simpler quick-drying process. Further disadvantage is that the useful fibrous materials - which otherwise represent the fundamental fodder for the ruminant animals - do not get into the concentrate, thus they cannot be utilized.

Also such process is known in which the protein content of the pulped vegetable matter is coagulated at about 40-80 C and the obtained dispersion is dewatered with centrifuge to minimum 65% water content then the so-obtained material is further dried with hot flue-gas until the water content is reduced to 10-12%. The still utilizable material is separated with purification, filtration or settling from the juice separated during the dewatering process, and thois too is dried together with the dewatered vegetable matter. The so-obtained product is mixed with other fodder, or with basic material of food.

Advantage of the process is that quality of the flour obtained as the end-product is better, than that of the flour made of fodder with flue-gas only, since the protein content is caramelized to a lesser degree and its nutritive content is also higher. Its drawback is however that the cost of investment is relatively high and the cost of operation during the process is also high. Further drawback is that the period of coagulation is not regulated, hence part of the protein and carotene content of the fodder decomposes.

Another drawback is that the fibre content of the original plant is physically annihilated, thus its endproduct is low-grade flour.

In view of above it is apparent, that by the presently known processes the green vegetable matter of protein content are processed with low efficiency and quality of the obtained product is not satisfactory either (see traditional drying with flue-gas, or the solution published in No. H 1814 disclosure document). The process ensuring a product of higher quality (see patent No. 167 839) increases the cost of processing considerably, while loss of the inner substance is still relatively significant.

If practically the total quantity of the valuable inner substance is to be recovered (see patents No. 113 249 and 153 580), it can be realized at the present only at high cost of investment and operation, and the possibility for an economic process exists only if the continuous supply of the vegetable matter to be processed is ensured furing the whole year, while its end-product and by-product -- by themselves -- are not suitable forthe feeding of animals.

The present invention is aimed at working out such process for the preservation of green vegetable matter of protein content, which permits the production of product preserving practically the total inner substance of the plant without the need of costly invenstment and expensive operation.

The set objective according to the invention is solved in such a way, that in the process of preservation of the green vegetable matter of protein content when the harvested plant is smashed to pieces and coagulated at 40-1 00'C temperature -the smashing is carried out in the form of crushing, advisably by passing the harvested plant through rolls of varying speed. The crushed material is coagulated for 24 minutes and dewatered exclusively by mechanical means.

The coagulation is carried out at 60-75"C temperature during the process according to the invention.

The mechanical dewatering may take place with vacuum filtration, centrifuging, vibration, compression or by other similar methods.

In a preferable alternative of the process according to the invention the technological steps are reversed, and first a certain part of the moisture is mechanically removed from the crushed vegetable matter.

However the dewatering is carried out by preserving 30-50% of the original protein content in the fibrous material so that the fibrous material (hay) should be well utilizable for feeding. Next the obtained fibrous material as well as the filtrate are separtely coagulated for 24 minutes and finally dewatered again by mechanical means.

After the final mechanical dewatering advisably antioxidant is added to the material and the product according to the given requirement is packed for instance in non-translucent material. The product may be produced in fibrous-, flour or pellet form.

The invention is based on the recognition, that practically the total quantity of the green vegetable matter can be preserved first by binding the proteins with coagulation to the plant fibres, then the water containing the nutritive material only in traces is mechanically removed. This way by omission of the drying with heating, the quality of the nutritive material does not deteriorate. Naturally the dewatering should be carried out only until the balance of the moisture content is reached, because the protein in this condition can already be directly stored.

The process according to the invention is described in detail with the aid of non-limiting examples as follows: Example I Lucerne (medicago sativa) was harvested at the rate of 20 Vhour in one run. Water content of the fresh harvested lucerne was about 82%. The fresh lucerne delivered immediately was carried into the feeder silo with the aid of scraper chain conveyor.

The material was forwarded with cell feeder from the feeder silo in between spiked tearing rolls. After the preliminary mechanical smashing, the crushing of the material was carried out by passing the material through grooved rolls. The rolls rotate at different speed in orderto bring about sliding motion between the two hard surfaces. Speed of one of the rolls in 80, while that of the other roll is 100 r.p.m.

The crushing (crushed material) coming out of the rolls was coagulated with the admission of steam of 105 C temperature. The continuous agitation of the crushing was ensured in order to achieve uniform temperature distribution. Temperature of the coagulation was 60"C. The material was kept at the given temperaturefor2 minutes in average.

After the coagulation the crushing was carried onto a vibrating sieve of 2 mm mesh size, on which the moisture content was reduced to about 20%.

Next trusses of 50x50x50 cm edge length were compressed from the crushing. Further 8% water passed out of the material in the truss-press, thus 12% balance of water content set in.

The fibrous material produced with the described technology was analysed, according to which it conk tains about 95% ofthe original protein content and 98% of the original carotene content. Thus is is apparent that the inner substance of the material was nearly totally preserved during the process. In addition, the liquid passing off during the dewatering was filtered and the recovered colloids were returned into the fodderstill before the trussing.

Example 2 Torous dactylis was harvested at the rate of 25 t/hour. Water content of the fresh plant was 75%.

After the immediate delivery, the material was passed into the receiving shaft. From here it was fed with toothed elevator into the crushing apparatus.

The crushing was carried out between grooved rolls rotating at various speeds. Speed of the rolls was 60 and 40 r.p.m.

The coagulation in this solution was carried out simultaneously with the crushing by using heated rolls. Temperature of the rolls was 1 OO"C. The crushing and coagulation were carried out in such a way that the material should not stay between the rolls or in the space heated by them for more than 3 minutes. This way temperature of the coagulation was about 70"C and the period did not exceed 3 minutes.

Next the crushing was carried into a continuously operating centrifuge, in which it was dewatered until the balance of water content (12%) was reached. The finished fodder was put into stacks, then ground at a later stage. From a certain part of the ground product pellets suitable for feeding were produced. The protein and carotene content ofthe product was identical with ofthe one produced in example 1.

Example 3 Red clover was harvested at the rate of 20 t/hour.

After delivery the material was poured into receiving shaft to be carried by scraper conveyor to the crushing mill. The crushing was carried out between grooved rolls at the rate of 100 and 120 r.p.m.

The crushing passed from the rolls into the screw press which dewatered the crushing at a pressure of 4-5 kg/cm2.

Since at this implementation method coagulation was not carried out afterthe crushing, the liquid and fibrous material obtained as the product of partial dewatering also contained nutritive materials.

The liquid coming out of the screw press was conducted into a tank in which continuously operating coagulation was carried out at 55"C. The liquid remained in the coagulating tank for about 2 minutes.

The liquid coming out of the coagulating tank was conducted into a centrifuge were the water and nutritive materials were separated. The obtained nutritive material contained about 50% of the original protein content and about 60% of the carotene content of the plant. The material was preserved with airtight packing. Non-translucentfoil was used for packing.

Parallel with above, the hay coming out of the screw-press was treated with vapour of 100 C tem p- erature. The coagulation took place at 700C tempera - ture in the course of the treatment, the length of time was 4 minutes.

Then the crushing was forwarded into the vacuum filter where the further superfluous water content was removed. Water content of the finished fodder was 11% containing 45% of the protein and 38% of the carotene in the red clover.

Next the fooder was put into stacks and cake was produced for fodder from a certain part of it.

The introduced examples demonstrate that the process according to the invention can be applied in several alternatives and each of them can be realized relatively cheaply and economically. Thus one of the fundamental advantages is that the value of the energy used during the process related to the green material is much less than that of the earlier proces ses.

Further advantage of the process according to the invention is that the quality of the end-product is higher, than that of the earlier similar products, since the water content of the material is exclusively mechanically removed from the properly prepared green material. This way storage of the produced fodder may be carried out more reliably and for a longer period.

Fundamental advantage of the solution is that with the exclusively mechanical dewatering the fodder preserves its original character in respect of the fibr ous material and fibrecontent, taste, colour etc., while the products obtained with the earlier proces ses do not ensure this, even if the product was fibr ous material instead of low-grade flour.

Quality of the material produced with the process according to the invention is also proved by the fact, that the coagulation is carried out for maximum 4 minutes, thus the protein, or carotene decomposi tion does not arise. The heating of short duration does not destroy the vitamins (e.g. the Bcarotene).

Summing up it can be stated that the process according to the invention is suitable for such pro cessing and preservation of the green vegetable matter of protein content, which permits the produc tion of a product preserving practically the total inner substance of the plant and ensures a fodder of excellent quality. Use of the process does not require costly investment and the technology is also 'economical.

It is noted, that with the alternative of the process according to the invention -- at which the partial edewatering is carried out before the coagulation in case of necessity a product suitable for human purpose is also obtainable from the liquid containing nutritive material.

Claims (15)

1. A process for the preservation of green veget able matter of prtein content, comprising crushing the harvested plant so as to preserve the original fibrous character of the harvested plant, coagulating the crushed material over a period of 24 minutes at a temperature of 40-100 temperature and dewatering it exclusively by mechanical means until a suitable balance of water content is reached.

2. A process as claimed in claim 1, wherein after crushing, but before coagulation the crushed vegetable matter is subjected to a partial dewatering so that 30-50% of the original protein content should remain in the fibrous material, and then both the fibrous material and the liquor removed in the partial dewatering are separately coagulated.

3. A process as claimed in claim 1 or 2, wherein the crushing is carried out by passing the plant through the nip between rolls revolving at different speed.

4. A process as claimed in any preceding claim, wherein the harvested plant is subjected to a preliminary breaking-up treatment before crushing.

5. A process as claimed in any preceding claim, wherein the coagulation is carried out at 60-75"C.

6. A process as claimed in any preceding claim, wherein the dewatering is carried out by vacuum filtration.

7. A process as claimed in any of claims 1 to 5, wherein the dewatering is carried out by centrifugation.

8. A process as claimed in any of claims 1 to 5, wherein the dewatering is carried out by vibratory device.

9. A process as claimed in any of claims 1 to 5, wherein the dewatering is carried out by compressing device.

10. A process as claimed in any preceding claim, wherein antioxidant is added to the material after dewatering.

11. A process as claimed in any preceding claim, wherein the final product is ground to a flour.

12. A process as claimed in any of claims 1 to 10, wherein the final product is pelletised.

13. A process as claimed in any preceding claim, wherein the dewatered product is packed into a container of non-translucent material.

14. A process according to claim 1 substantially as herein described with reference to any one of the Examples.

15. A green vegetable feed product whenever produced by the process claimed in any preceding claim.