DK146351B - PROCEDURES FOR THE TREATMENT OF LEAVY VEGETABLES, ISRAZER LUCERNE - Google Patents

Description

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φ (12) PUBLICATION WRITING (11) 146351 B

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(21) Patent Application No: 4937/75 (51) Lnt.CI.3: A 23 K 1/14 (22) Date of filing: 03 Nov 1975 A23J 1/00 (41) Aim. available: 05 May) 1976 (44) Submitted: 19 Sep 1983 (86) International Application No: - (30) Priority: 04 Nov 1974 FR7436628 (71) Applicant: * AGROPROTEINE INDUSTRIE; Paris 8th, FR.

(72) Inventor: Charles * Gastineau; FR, Olivier de * Mathan; FR, Jan-Oomlnlque * Dllly; FR.

(74) Clerk: Hofman-Bang & Boutard_ (54) Procedure for the treatment of leafy vegetables, in particular alfalfa

The present invention relates to a method of treating leafy vegetables, especially alfalfa, on the one hand, to obtain a heat saving during the dehydration of the plants and on the other hand to recover the proteins present in the press juice.

It is known that green leafy plants usually used for animal feed can be subjected to a dehydration and conditioning treatment, thereby obtaining a feed in the form of cylindrical granules or pellets which are easier to store and transport. , and which have controlled characteristics. Lucerne is in this respect a plant material which is particularly well suited to animal H feed in dehydrated form.

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Methods are also known which enable the extraction of proteins from plants, such as alfalfa, by physico-chemical treatments of the juice resulting from the pressing of the raw plant material, cf. U.S. Patent No. 2,552,543 ·

This patent describes a method of treating leafy plants, such as alfalfa, in order to maintain a maximum carotene content in the product obtained. The processing of the alfalfa comprises a coagulation of the proteins, a pressing of the material and a separation of a cake from a liquid. Only the solid products present in the liquid, after being subjected to heating and decanting, are recycled to the pressing step.

It is important to reduce the necessary calorie consumption for the dehydration of the processed vegetables in order to preserve as much as possible. The known methods of dehydration e.g. of the alfalfa requires considerable amounts of fuel, such as oil, which, as is well known, is a costly raw material. It has been found that the pressing of the vegetable material enables extraction of a juice and obtaining a cake of pressed vegetables having a substantially lower moisture content than the moisture content of the starting material. Under these conditions, the later dehydration of the cake can be carried out under favorable economic conditions. Furthermore, the press juice often has a significant content of proteins, if any losses cannot be ignored. Thus, it is possible in a manner known per se to recover the proteins present in the juice.

The object of the present invention is thus to provide a method of treating leafy vegetables, especially fresh alfalfa, thereby achieving the following objectives; (1) a comprehensive partial extraction of the moisture present in the starting material; and (2) a maximum heat economy during the dehydration of the press cake having a substantially reduced moisture content.

Thus, the present invention relates to a process for treating leafy vegetables, especially fresh alfalfa, and the process of the invention is characterized in that a) heat treating the raw vegetable material in a moistened pre-treatment step at least about 20 hours. 85 ° C by bringing the material into intimate contact with a pre-heated to 90-100 ° C reheated moist machine. b) and pressing the hot material from step a) to the desired degree of partial dehydration, preferably 40-65% of the original moisture content of the starting material, thus providing a partially dehydrated material and a liquid product, called serum, which is collected at the exit from the pressing step and partially recycled to step a).

According to the invention, the serum obtained from the pressing step is re-heated, thereby raising its temperature to a value capable of ensuring flocculation of the protein substances in step a), more specifically to 90-100 ° C. This method results in flocculation of the chloroplastic proteins and cytoplasmic proteins in the plant cells themselves, as well as flocculation of the proteins in the serum obtained by pressing. Furthermore, thanks to the prior heat treatment of step a), a flocculation of proteins in the released juice is obtained in the package and from the exposed parts of the plant tissue, which juice is already mixed with the mass of cut plant material. Prior to step a), the fresh plant material may be subjected to mechanical disintegration in a suitable tear-off device which causes a cutting of the tissues, or in a hammer mill type apparatus which causes a crushing of the tissues. However, this operation is not mandatory and it may even be advantageous and more economical to avoid it before carrying out the method of the invention.

The method according to the invention aims, among other things, to collect as much protein as possible in the press cake. In other words, we aim to limit the diffusion of protein into the liquid phase as much as possible. The optimal coagulation of protein in the press cake is achieved by using a very large amount of hot press juice in the heating step (3-6 parts by weight of press juice per part by weight of fresh vegetable material). In this way it is also avoided to destroy the heat-sensitive constituents of the leaves (eg xanthophyl), which are easily destroyed if the heat treatment is carried out dry.

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By bringing the vegetable material into intimate contact with a large amount of recycled heated press juice, you achieve a simultaneous heating and soaking of the material. This results in a homogeneous heat treatment which is gentle on the heat-sensitive constituents of the material and the thorough soaking causes a softening of the plant tissue, which facilitates subsequent pressing. In this way, a press cake with a higher content of solids is obtained than is obtained by a dry heat treatment.

When treating alfalfa, serum preheat is calculated to obtain a mixture of serum and green alfalfa having a homogeneous average temperature of 80-90 ° C for the entire duration of step a).

For this purpose, the collected serum is collected from the outlet of the press by pumping and reheated in known manner, especially when passing through a heat exchanger fed with water vapor. The serum thus heated to 80-90 ° C is partially returned to the fresh alfalfa at the entrance of a suitable mixing apparatus. Any suitable conveyor mixing means capable of ensuring intimate contact between the fresh vegetable material and the recirculated serum from the pressing step may be used. A particularly suitable means is a double screw conveyor mixer wherein the insertion of the reheated serum is made near the entrance of the vegetable material.

For a serum with a temperature of about 85 ° C, the residence time of the alfalfa in the mixture is of the order of 5-8 minutes. Thus, one skilled in the art can readily determine the mixing parameters by taking into account the particular characteristics of the apparatus used and the vegetable material used, so as to obtain at the end of the apparatus a material in which the serum is uniformly distributed and the temperature between the material mass and the serum is equilibrated.

In the treatment of alfalfa, the most advantageous conditions for the comminution-diffusion operation, combined with the flocculation of the precipitated intracellular protein substances in the vegetable cells, are as follows:

Temperature of the mixture of serum and fresh alfalfa: 80-95 ° C, preferably 85-90 ° C.

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3 to 6 parts by weight of serum 1 part by weight of fresh alfalfa, adjusting the pH to a value of 5-6, residence time: 5-8 minutes.

As noted above, flocculation of the protein materials in the transport mixer is performed in step a). At the end, the protein clot formed in the green juice gives rise to a serum which is later extracted from the press. For the purposes of the invention, a continuous high-pressure continuous press of the "Wheel Press" type is used, which is manufactured, for example, by the companies "Davenport Press" and "Rietz". These are presses consisting of two wheels whose axis of rotation is inclined to the horizontal.

The two wheels form such that V, which enables a feed of the alfalfa to the open part of the V and a pressing and extraction of juice from the closed part of the V, a continuous worm press with good yield can also be used, f .g. of the type "Stord" or "Spei-chim".

You get at the end of the press:

A cake whose weight represents 50-40% by weight of the alfalfa originally used. This cake has a solids content of the order of 35-48:.

A serum whose weight represents 50-60% by weight of the original fresh alfalfa. This serum has a dry matter content of the order of 10-5%.

The cake can be dehydrated and then agglomerated in the press in the form of pellets in known manner.

The serum is partially recycled for treatment step a) after preheating to 90-100 ° C to heat the fresh alfalfa.

The majority of the serum can be concentrated in a triple or quadruple power apparatus to obtain a concentrated serum having a solids content of the order of 50-65%.

In dehydrating the alfalfa, the preheat of step a) of the process according to the invention provides the necessary caloric supply for the final dehydration in a drying means applied to the after-press. According to the invention, the collected serum after the pressing step is partially recycled for treatment of the raw vegetable material. This treatment is carried out in a humid way during heating, as mentioned, the serum is heated before recycling.

It should be emphasized that the heating and bleeding during the processing of the raw vegetable material together are two important factors. The bleeding modifies the structure of the vegetable tissue and thus enables a more extensive squeezing of juice during the later pressing step. This has the advantageous consequence that the dry matter content of the cake is high (35-48? 0), which is a value substantially higher than that of the cakes obtained by the prior art;

During the heat exertion, all the proteins are precipitated, thanks to the treatment in question, a significant reduction in the amount of proteins in the serum is achieved. Thus, this can advantageously be used as a bleeding and heating medium.

The process according to the invention is further illustrated with reference to the drawing which schematically shows the most important steps, including the circulation of the various materials.

The lucerne is introduced into a humidifying bleaching type heat treatment apparatus in the presence of a certain amount of recirculated serum. The temperature in this first step is £. of the order of 85-90 ° C. The hot alfalfa is then subjected to a pressing to obtain a serum and a cake. The cake, which has an average dry matter content of $ 35-48, is subjected to a classic dehydration. Thus, a dehydrated lice flour is obtained which is converted into dehydrated pellets in a classical agglomeration or pelleting press.

The serum is partially recycled after reheating, e.g. to 90-100 ° C. The amount of serum recirculated depends solely on the calorific needs of the heat treating apparatus, taking into account the mucus mass to be treated and the temperature desired. The weight of imported recirculated serum is usually approx. three times the weight of alfalfa to be treated. The remaining serum, which is the predominant portion, is subjected to a concentration which gives a syrup having a dry matter content of the order of 50-65%.

However, if the initial moisture content of the fresh alfalfa is relatively high, the recirculation coefficient of the serum can be limited by directly adding calories in step a), e.g. by immersing a heating coil flowed by a hot fluid such as water vapor into the reaction medium.

The process in question is perfectly suited for continuous operation.

The invention is further illustrated by the following example:

EXAMPLE

100 kg of green alfalfa with a dry solids content of 20.7% and containing 16.80% protein in the raw material is added to 600 kg of serum heated to a temperature of 95-100 ° C so that the mixture reaches the temperature 85 ° C quickly. The mixture is kept at this temperature for 8 minutes.

The hot alfalfa is pressed after draining. On the one hand 42.5 kg of press cake with a dry matter content of 40%, of which 17,7% are protein substances, are obtained and on the other hand 101,5 kg of a pressed juice with a dry matter content of 6,2% and containing in total 13.00% nitrogen-containing materials, and 556 kg of drip juice with a dry matter content of 4.70%, containing a total of 12.20% nitrogenous substances.

These two juices are mixed and recycled in an amount of 600 kg after reheating to the fresh green alfalfa while the rest, ie.

57.5 kg, concentrated to form a syrup with a solids content of 50-60%.

The cake is dehydrated to give 18.9 kg of pellets with a moisture content of 11%.

The evaporated water in the dryer is 23.6 kg.