AU594092B2

AU594092B2 - Process for the simultaneous recovery of wheat starch and wheat gluten

Info

Publication number: AU594092B2
Application number: AU64523/86A
Authority: AU
Inventors: Helmut Kalb; Dioeter Kopf; Harald Nurnberger; Gunther Propok; Rolf Schirner
Original assignee: Staerke & Kartoffelver Veb
Current assignee: Ve Kombinat Starke und Kartoffelveredlung
Priority date: 1985-10-30
Filing date: 1986-10-29
Publication date: 1990-03-01
Anticipated expiration: 2006-10-29
Also published as: HU199068B; BG47408A1; EP0221427A2; DE3689509D1; DD258718A3; EP0221427B1; ATE99700T1; JPH0648954B2; AU6452386A; JPS6394942A; HUT44423A; EP0221427A3; PL262129A1; PL149174B1; CS701786A1

Abstract

The process for the separate extraction of all the principal constituents of flour from dry milled wheat products entails an aqueous suspension of milled products with a water/flour ratio of 1.0 - 3.0 being prepared and further reduced in size by a wet mechanical method, and the milled product suspension being adjusted to a temperature of 20 - 50 DEG C and subjected to a resting period of 5 - 120 min. The suspension of milled wheat product is subjected to a one-stage three-phase hydraulic classification in a centrifugal field to separate out the sediment containing the coarse grain starch, and the continuously produced centrifuge supernatant is fractionated by controlled phase separation in the centrifuge into a light phase containing the flour extractives and into a heavy phase containing flour gluten. The heavy liquid fraction with the partially agglomerated flour gluten is taken off above the centrifuge bowl and the light liquid fraction containing flour extractives is taken off at the upper edge of the centrifugal separating chamber. The processing of the intermediate products to the final products of coarse and fine grain starch, wet gluten and flour extract entails the material streams being passed countercurrently and thus the fresh water requirement being reduced to less than 2 m<3> per t of milled product, with an overall yield of up to 98 %.

Description

594092 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 SUBSTITUTE COMPLETE SPECIFICATION FOR OFFICE USE Form Short Title: Int. Cl: Application Number: Lodged: *I .9 0 C904 a, Ce Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: This doumnt contains the arn ncdmennt made uner Section 49 and is correct for printing.

Related Art: 4 9 &1 1 O O i TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: VE KOMBINAT STARKE UND

KARTOFFELVEREDLUNG

Mansfelder Str. 58, Halle (Saale), German Democractic Republic 4020 Rolf Schimer Harald Nirnberger; Helmut Kalb Gunther Prokop and Dieter Kopf GRIFFITH HACK CO.

71 YORK STREET SYDNEY NSW 2000

AUSTRALIA

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Complete Specification for the invention entitled: PROCESS FOR THE SIMULTANEOUS RECOVERY OF WHEAT STARCH AND WHEAT GLUTEN Te following statement is a full description of this invention, including Sbest method of performing it known to me/us:-

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/i r" 1 .4 #4) 0 0, A 4 At :4g "11 0 The invention relates to the simultaneous recovery of wheat starch and wheat gluten from dry wheat meal by means of a centrifuge process.

The production of wheat starch from aqueous wheat meal suspensions was first suggested by A. Fesca (Otto, Fr., The manufacture of vinegar, sugar and starch; Verlag Vieweg, Braunschweig 1867, p 502). The process suggested by A. Fesca entailed the manufacture of a viscous mixture of flour and water by means of an agitator and the subsequent centrifugation of the mixture of flour and water in a settling centrifuge having a drum without screen.

During chargewise centrifugation of the suspension of flour and water the course starch settles at the inner periphery of the massive drum in a coherent layer, whereas thereabove in the difficultly sedimentable supernatant liquid the gluten, the fine starch, the fibres and the soluble wheat meal components accumulate, partly in a compact form and partly in a suspended form.

,20 During the formation of a compact gluten layer the viscous gluten has to be removed from the centrifuge drum by heavy and cumbersome manual labour. As moist gluten can essentially be produced in a more simple manner by the Martin process, the Fe!ca process has not been carried through. Several suggestions have been made to improve the Fesca process. According to DRP 200774 these proposals concern the use of a meal extract, According to FF 529951 a proteolytic enzyme is used such as trypsin and pepsin. Further proposals concern the use of alkali (USP 30 2455981) or ammonia (USP 3574180).

The above mentioned processes improve the separating conditions or the starch yields, however the consistency of the gluten is damaged to such an extent that cohesive moist gluten can no longer be obtained.

'35 It is also known that investigations have been carried out to separate mixtures of flour and water by means of horizontal screw centrifuges. It was established -e u d~ jl i!"

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I, inr (Fellers, Johnston, H.PH.; Smith, Mossmann, Sheperd, Process for protein/starch separation in wheat flour. Food Technology 23 (1969) 4, 560-564; Johnston, H.Ph; Fellers, Process for protein 5 separation in wheat flour, 2. Experiments with a continuous decanter type centrifuge. Journal of Food Science 36 (1971) p 649-650), that an acceptable separation of the starch from mixtures of flour and water can only be obtained in a very limited range of the water/flour ratios and that the separating behaviour is very significantly affected by the morphological characteristics of the flour gluten. Apart from the very narrow water/flour ratios characteristic for each type and charge of flour, the separating conditions deteriorate drastically. For example, larger gluten particles may be discharged together with the coarse starch containing sediment, or, in an extreme case, the entire centrifuge drum may be filled up with gluten so that the fed mixture of flour and water largely leaves the centrifuge 20 unseparated.

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*1cQ I c According to DE-OS 2345129 a multi-stage process for separating gluten from wheat flour is also known. In this process a mixture of flour and water is made having a water/flour ratio of from 1.2 to 2.0. A range of 30-50 C is selected for the temperature of the mixing water. The mixture of flour and water having a temperature of 30-50 C is separated and classified in a centrifuge. To produce or separate the moist gluten, the centrifugate of 30-50 C is processed for a long time in 30 a large volume vessel and then mechanically treated intensively with processing water in a mixing device to form coherent moist gluten agglomerates. After termination of the two-stage after treatment the secondary moist gluten agglomerates are separated from the 35 centrifugate of the primary classification by screening S and further washed by adding fresh water.

The process described is costly as far as equipment r it i I a ";t 4589S/bm -3x; Is i __7 04 04 0 0) 04 0..I 1 I It is concerned because of the long time treatment and is microbiologically susceptible. A rather large amount of highly loaded waste water accumulates.

A multi-stage centrifuge process (Starke 32, 1980, 4, p A 45) for treating mixtures of flour and water having a temperature of 30-50 C is also known. Typical for this process is the use of a flowable mixture of flour and water having a flour/water ratio of 1.0 and the successive centrifugate treatment of the mixture of flour and water as well as the centrifugate of the primary classification with decanters. This process is costly as far as equipment and energy are concerned and, in addition to this, necessitates the use of high speed centrifuges having a centrifugal acceleration of 3000-4000 g by means of which from the highly consistent mixture of flour and water a dry mass rich secondary centrifugate with sufficient cohesion can be obtained which can be washed in conventional gluten washing equipment.

o Object of the invention is to simplify the process o20 for centrifugal separation of mixtures of flour and water as far as equipment is concerned, to reduce the electrical energy and usage of fresh water, to increase the total dry substance yield and to obtain a quality of flour which is t substantially constant.

The underlying thought of the invention is to essentially improve the conditions of centrifugal separation of mixtures of flour and water with the object of a complete recovery of the wheat flour, the moist gluten and other flour conta.Lning substances, and to make the separation effective also in a large range of water/flour ratios and at different morphological characteristics of the flour.

According to the invention there is provided a process for the simultaneous recovery of wheat starch and 35 wheat gluten, which comprises: preparing from dry wheat meal and water a coarse dispersed meal/water mixture having a flour/water ratio of 4589S/bm -4-

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from 3.0 to 1.0,preferably of from 2.0 to 1.0, the coarse dispersed aqueous meal mixture being wet-mechanically further reduced to a free flowing flour/water mixture; drawing off a heavy centrifugate fraction continuously from the clump-free flour/water mixture through a one step three-phase flow sizing in the centrifugal field of a helical-conveyor centrifuge at the periphery thereof, the heavy centrifugate fraction essentially consisting of wheat gluten and some wheat starch; 0 0 0 on 0 o9 o 00

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*00 0 0 0 0044 00 0 0 *0449 009 00 0 00 *9 S9 r Ct I ttCr removing a light centrifugate fraction from the inner surface of the hollow cylindrical product ring, which essentially contains the main portion of genuinely and colloidally dissolved flour substances and some fine 15 starch particles, and removing the sedimented coarse starch particles from the centrifugal separator through the centrifuge spiral; separating fine starch particles from the light centrifugate fraction by centrifuging and converting the dry mass rich flour extract by thermal concentration into a flour extract concentrate; converting the heavy centrifugate fraction by treatment with water in a mechanical reducing device to form gluten curds, flakes or rods from the flour gluten; 25 separating the starch from the gluten wash water by centrifuging or gravity sedimentation and refining the sedimented fraction by resuspension, multiple screening and solid/liquid separation; and converting the treated coarse and fine wheat starch particles, the moist gluten and the concentrated flour extract into dry products in a suitable manner.

According to the invention the light centrifugate is worked to a thermally concentrated flour extract. To this end the fine starch is separated from the light centrifugate by centrifugal treatment. An aqueous flour extract having a dry mass of approximately 2.5-8.0% is thereby obtained according to the water/flour ratio used and other process conditions. This is concentrated by ,.AZA9S/bm 1.

i i1 j i j;h 4 ao o4 o 00 0 04 O 0 o 00 0P 00 o*<o o 00 0 00 90 0 00 00 0 404 thermal treatment in suitable evaporating equipment to a dry mass of 10-45%, preferably 20-25%.

According to the invention the heavy centrifugate is worked to a moist gluten. To this end the heavy centrifugate is introduced into a suitable extraction device and worked to a moist gluten having a high protein content by means of treatment with water, or other suitable solvent and apparatus.

According to the invention a refined coarse starch is obtained from the sediment fraction after resuspending, multiple screening and mechanical solid/liquid separation.

According to the invention the fine starch is obtained by centrifuging the light liquid gluten wash water and under certain circumstances by centrifuging the processing water to be recirculated. In other embodiments final flour and meal products are used. These include products of wheat dry milling plants such as conventionally and otherwise milled flours, semolina, fine 0 grist etc. and other mechanically reduced dry products of ?0 wheat including air separated flours.

Relative to the prior art the process of the invention is distinguished by several advantages and particularities.

For example, by using the invention, it is possible to provide a technically and economically effective preparation of wheat starch, wheat gluten and simultaneously all other flour containing substances from flour to fine semolina meal products as well as bakable to non-bakable wheat meal products. The use of a coarse meal product such as fine semolina may be of advantage during preparation of the suspension. Also when there is a wide distribution of particles in the meal with a large proportion of undersized and oversized material, the process of the invention is acceptable. The essential p5,. feature of the invention is the three-phase separation of the mixture of meal and water in the centrifuge -separator. During the operation of the centrifuge the 17 separator. During the operation of the centrifuge the rl kb toI c r 4( E L t CI r rsrEP P.

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i rr i 4589S/bm centrifugal space is formed by an accumulating product ring. Contrary to the prior art the process conditions are selected so that a permanent separation of the liquid phase occurs in a stationary fashion. This leads to a continuous separation process, also contrary to the prior art, because of suitable discharge conditions which do not fill the product ring with wheat gluten, but because of an additional discharge at the periphery of the separating space.

By means of the process of the invention the separation which is dangerous under conventional S conditions is carried out as a systematic process feature. The process conditions for a controlled separation of the liquid phase in the centrifugal field of S* °°15 a helical-conveyor centrifuge, in a light centrifugate largely containing the genuinely and colloidally dissolved meal substances and some fine starch, and a heavy centrifugate containing the main portion of the flour gluten and some fine and coarse starch, can be reproduced in a range of clear surface load of 0.02 to 1.45m, Spreferably 0.1 to 0.4m 3 of meal/water suspension per 100 m of clear surface per hour.

sp No high speed decanter is required to carry out the f r T process of the invention. Decanters with a centrifuge coefficient of 3000 g and 2000 g are optimal for the t process. Even at smaller acceleration the process can be carried out in a stable manner. The use of high speed decanters can be disposed of.

A particularly preferred feature of the invention is the controlled separation. Consequently a light liquid centrifugate being highly concentrated processing waste water can be produced which has a dry substance content of more than 4.5% at favourable process conditions. This provides extraordinarily energy and cost favourable conditions for the preparation of a thermally concentrated liquid or dry product. With the separation of the centrifugate fraction and the formation of an aqueous phase as the light liquid phase, the flour gluten is /bm t _r simultaneously enriched in the heavy liquid phase.

The stationary reduction in strength of the heavy phase of genuinely and colloidally dissolved substances forced in the centrifugal field and the simultaneous enrichment of the flour gluten are the prerequisite for a partial agglomeration of the flour gluten from the previously agglomerate-free meal product suspension. The thus partially agglomerated flour gluten can be discharged in a flowable manner at the periphery of the centrifugal separating space or from the inside of the centrifuge drum.

The agglomeration of the flour gluten has then proceeded to such an extent that the heavy liquid centrifugate can be immediately fed into a conventional extraction device and can be further washed there at small cost, for example with recirculated processing water.

In the process of the invention the processing water accumulates in the highest possible concentration of substances, which may be up to already at the o° beginning of the process. This is a prerequisite to 20 consequently provide the flow of the "starch" and "processing water" in a countercurrent fashion. It is S then possible to exclusively use fresh water for the Srefining of the starch and also to employ partiall- or completely recirculated processing water for the preparation of the aqueous meal suspension. By means of the consequently countercurrent flow of substances it is possible to reduce the specific usage of water to less than 2 m 3 per t of meal processing.

The process of the invention is carried out in a range 1.0 to 3.0 for the water/flour ratio. The preferred water/flour ratio is 1.0 to 2.0. An even more preferred Sc range is 1.2 to 1.6. A high concentration of soluble flour substance-i in the light centrifugate is obtained in the preferred range. Up to 80% of all soluble flour S:4t'35 containing substances may go over into the centrifugate so that the one step three-phase separation of the fed meal suspension according to the invention is combined with a 4589S/bm 1 o u io i rang is1.2to 16. hih cocenraton o soubl 1 ty-" normal "flour washing".

A special preparation of the meal suspension may be significant as part of the process of the invention.

A feature of the preparation according to the invention is the adjustment to a certain temperature of the mixture of meal and water. It is preferred to adjust the temperature to 20-50 C. A more preferred range is 25-45 0

C.

A further feature of the preparation according to the invention is to observe a short steady pause for the heated meal/water mixture before carrying out the three-phase flow classification. During the steady pause the meal/water mixture is stirred in water. The steady pause is in the range of from 5 to 120 minutes. The preferre. range is from 5 to 90 minutes.

Relative to the production of gluten the process of the invention may be varied.

Thus, at normal qualities of wheat or the meal S products made therefrom, it is possible to introduce the 0 heavy centrifugate fraction which largely contains the flour gluten immediately into a conventional washing device and to work it to a moist gluten of more than 'protein (factor 6.25) in a shorter operation. As the flour gluten of the process of the invention is already partially agglomerated in the heavy centrifugate fraction, further concentration to a high protein moist gluten may also be obtained by a one or two times coarse pulverization and screening whilst adding water. For poor meal qualities which, for example, can be made from feed wheats and which are characterized in certain circumstances by a smudgy gluten, it may be advantageous i when a protein enriched kneaded dough poor in soluble substances is made from the heavy centrifugate fraction by adding and mixing flour and the kneaded dough is washed 0:6 t '35 out in a conventional washing device.

The process of the invention is characterized by a great economy subject to uncomplicated process technical 4589S/bm -9features relating to equipment used.

The use of electrical energy can be essentially reduced by the one step decanter separation and the very simplified gluten preparation. Because of the favourable countercurrent flows of substances no waste water practically accumulates from the process. The flour extract having a dry mass of more than 4.5% produced in the process is an aquec;s end product. Each further working up of this end product is economically justified at a dry mass of Total yields of flour dry masses up to 98% are obtained.

The invention will now be further explained by means of suitable embodiments. The accompanying drawings show: Figure 1: a block diagram of the process for recovery of wheat starch and wheat gluten by three-phase flow classification in a centrifugal zone; Figure 2: a block diagram of the process for recovery of wheat starch and wheat gluten by one-step three-phase separation of the aqueous meal suspension and screen classifying preparation of the heavy centrifugate fraction; Figure 3: a block diagram of the process for recovery St of wheat starch and wheat gluten by one-step three-phase t separation of the aqueous meal suspension and subsequent compacting of the heavy centrifugate fraction by adding a small amount of meal thereto, and extraction of the further treated heavy centrifugate fraction in a Sconventional waste water apparatus.

EC ~Example 1: Preparation of wheat coarse and wheat fine starch, 30 moist gluten and liquid flour extract from a feed wheat I flour (block daigram 1).

w For the preparation of a centrifugally separable meal/water mixture 1 wheat meal of a non-bakable kind of wheat is combined with recycled processing water 10.1 35 having a temperature of 35 C to a coarse dispersed flour/water mixture and further treated in a toothed disc mill. A smooth, lump free, good flowable flour/water 4589S/bm i -0- ,ri jT .1 a ro o o o 0 0 p 0 o Qo 044 o 0* C p mixture 1 is thus obtained which has a water/flour ratio of 1.6 kg of water per 1.0 kg of flour.

By carrying out the three-phase separation of the aqueous flour suspension by flow classification in the centrifugal zone, 2.4 m /h of flour suspension are fed into a specially prepared long tube decanter having a drum diameter of 500 mm, a degree of thinness of H 2.7 and a maximum separating factor of 1950 g. especially prepared to carry out the separation according to the invention.

In the three-phase flow classification 2 of the invention in the centrifugal zone there is obtained a sediment fraction SF predominantly consisting of coarse starch A a heavy centrifugate fraction SFF predominantly consisting of gluten FK and fine starch B a light centrifugate fraction LFF predominantly consisting of aqueously dissolved flour substances and some fine starch B.

The sediment fraction having a protein content of 20 0.95% is resuspended 3 with recycled processing water 6.3 and screened twice 4. The crude starch milk which is S screened and freed of bran and fine fibres FF is drained through a decanter 5. The dewatered wheat starch is again resuspended with fresh water FW and drained through a rotary filter 6 without cells. The refined coarse wheat starch A has a protein content of 0.48%.

The heavy centrifugate fraction SFF is washed in a conventional extraction device 9. Recirculated but slightly loaded processing water 5.9 is used as the gluten washing water. After treatment with water there are obtained a concentrated moist gluten FK having a protein content of 82% and a fine starch containing washing water. The thin starch suspension flowing from the extraction device is centrifuged 10 to separate the starch. The fine starch B has a protein content of 2.8%.

The coarse starch A and the fine starch B can be transferred to the dry product through conventional flow, 4 At~ V Cr *1 I FC 4589S/bm 4i 1 r- mill or roller drying.

The fine starch B is separated from the light centrifugate fraction LFF in a rapid decanter 7 and combined with fine starch B recovered from the bhavy centrifugate fraction SFF by washing.

By evaporating by means of a multi-stage down-draught evaporating apparatus 8 the aqueous flour extract having a dry substance content of 4.35% is worked to a thermally concentrated flour extract ME having a dry substance of 25% and a protein content of 21.4%. In carrying out the process of the invention according to example 1, there is obtained, relative to the wheat flour, 57% of coarse starch A with 14% of water, 20% of fine starch B with 14% of water, 35% of moist gluten FK and 31% of liquid flour extract ME.

Example 2: Preparation of wheat coarse and fine starch, moist gluten and liquid flour extract from winter wheat flour 00 So (block diagram 2).

0 To prepare a centrifugally separable flour/water 0 0 mixture 1 wheat flour is combined with recycled processing water 11.1 to a coarse dispersed meal/water mixture and mechanically further pulverized in a toothed disc mill. A «smooth, lump free, well flowable flour/water mixture 1 is thus obtained which has a flour/water ratio of 1.6 kg of water per 1.0 kg of flour.

I When carrying out the three-phase separation of the aqueous suspension of flour by flow classification in a centrifugal zone, 2.4 m /h of flour suspension is fed into a long tube decanter having a drum diameter of 500 mm and a slimness degree H 2.7 especially prepared to i,4 carry out the separation according to the invention.

In the three-phase flow classification 2 in the centrifugal zone according to the invention there are obtained a sediment fraction SF predominantly consisting of coarse starch A, 4589S/bm -12t 4 f 1 l L i t..

substances and some fine starch B.

a heavy centrifugate fraction SFF predominantlycled pr consisting of gluten FK and fine starch B, crudea light centrifugate fraction LFF predominantly consisting of aqueously dissolved flour containing 5 substances and some fine starch B.

The sediment fraction is resuspended with recycled processing water 6.3 and screened twice 4. The screened crude starch milk freed from bran and fine fibres FF is drained through a decanter 5. The dewatered wheat starch is again resuspended with fresh water FW and drained through a rotary filter 6 without cells. The refined coarse wheat starch A has a protein content of 0.3%.

The heavy centrifugate fraction SFF is mechanically dispersed 9 by adding processing water 5.9 and the heterogenous mixture of suspended starch and gluten particles is subjected to a screen sizing 10 by means of a curved screen. The gluten FK accumulates as a screen turn over. The suspended fine starch B is in the screen pass through. The screen turn over is mechanically dispersed once again to further concentrate the gluten content in the recycled processing water and screened once more. The moist gluten can then be dried or worked otherwise. The material which has passed through the screen is Stc' centrifuged 11 so that a recyclable processing water 11.1 is obtained.

When carrying out the process of the invention according to example 2, there are obtained 56% of coarse starch A, 18% of fine starch B, 40% of moist gluten FK and 1 35% of flour extract ME, relative to the wheat flour.

Example 3: S Preparation of wheat coarse and fine starch, moist gluten and liquid flour extract from a feed wheat flour (block diagram '11 To prepare a centrifugally separable meal/water S mixture 1, wheat flour of a non-bakable wheat type is combined with a 1.4 fold amount of recycled processing water 12.1 at a temperature of 25 C to a coarse 4589S/bm -13r i 1 i dispersed flour sludge and further pulverized mechanically by means of a toothed disc mill. A smooth, well flowable flour suspension is thus obtained.

When carrying out the three-phase separation of the aqueous flour ~'nspension by flow classification in a 3 centrifugal zone, 2.2 m /h of flour suspension are fed into a long tube decanter having a drum diameter of 500 mm and a slimness degree I 2.7 especially prepared to carry out the separation according to the invention.

In the three-phase flow classification 2 in the centrifugal zone according to the invention there are obtained a sediment fraction SF predominantly consisting of coarse starch A, a heavy centrifugate fraction SFF predominantly consisting of gluten FK and fine starch B, a light centrifugate fraction LFF predominantly consisting of the aqueous dissolved flour containing substances and some fine starch B.

2Q, *0 The sediment fraction is resuspended 3 with recycled 4 processing water 6.3 and screened 4. The screened crude starch milk is drained through a decanter 5. The sdewatered wheat starch is again resuspended with fresh water FW and drained through a rotary filter 6 without cells.

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I: r rosrr "i r The heavy centrifugate fraction SFF is intimately mixed in a kneading device with 650 kg/h of wheat flour from the flour storage 0 and a protein enriched kneaded dough 9 is thus prepared. The kneaded dough is 30 subsequently separated in moist gluten FK and starch milk in a conventional washing device 10 by adding processing water 5.10. The coarse starch A obtained from the starch milk is separated by means of a decanter 11 and further worked together with the sediment fraction SF from the 35 three-phase separation. The starch milk which still contains fine starch B only after separation of the coarse starch A is again centrifuged 12 to concentrate the fine 4589S/bm i ~7 c.

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7 -14iA ~4i starch B.

The fine starch B is separated from the light centrifugate fraction LFF by centrifuging 7 and combined with the fine starch from the washing of the kneaded dough.

The dry mass rich processing water from the centrifugation of the light centrifugate fraction LFF is worked to a liquid concentrated flour extract ME by evaporating in a multi-stage down-draught evaporator.

According to this process there are obtained, relative to the wheat flour, 60% of coarse starch A with 14% of water, 18% of fine starch B with 14% of water, 36% of moist gluten FK and 32% of flour extract ME with 25% of dry substance.

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Claims

1. A process for the simultaneous recovery of wheat starch and wheat gluten, which comprises: preparing from dry wheat meal and water a coarse dispersed meal/water mixture having a flour/water ratio of from 3.0 to 1.0, preferably of from 2.0 to 1.0, the coarse dispersed aqueous meal mixture being wet-mechanically furt' reduced to a free flowing flour/water mixture; drawing off a heavy centrifugate fraction continuously from the clump-free flour/water mixture through a one step three-phase flow sizing in the centrifugal field of a helical-conveyor centrifuge at the periphery thereof, the heavy centrifugate fraction essentially consisting of wheat gluten and some wheat starch; *b e o6 0 0 0 3 D D a. 0S (8 5 *o 0

5. t 4 5 L 8 0C~r removing a light centrifugate fraction from the inner surface of the hollow cylindrical product ring, which essentially contains the main portion of genuinely and colloidally dissolved flour substances and some fine starch particles, and removing the sedimented coarse starch particles from the centrifugal separator through the centrifuge spiral; separating fine starch particles from the light centrifugate fraction by centrifuging and converting the 25 dry mass rich flour extract by thermal concentration into a flour extract concentrate; converting the heavy centrifugate fraction by treatment with water in a suitable extraction device into moist gluten; separating the starch from the gluten wash water by centrifuging or gravity sedimentation and refining the sedimented fraction by resuspension, multiple screening and solid/liquid separation; and converting the treated coarse and fine wheat starch particles, the moist gluten and the concentrated flour extract into dry products in a suitable manner. 2. Process according to claim 1, which comprises: taking up the heavy centrifugate fraction with fresh ;1 ll i i- i 4o -16- K 4' L~ r '*w i, 9 o 0n Do a o **01 0 q9 09a 1f e Io 09 6 0090 4,. water or recycled processing water and dispersing in a mechanical reducing device; converting the flour gluten into gluten curds, flakes or rods; separating the gluten from the other suspended or dissolved substances by screening; and again repeating the mechanical dispersion and screening to separate the non-protein components in the moist gluten according to the desired protein content of the moist gluten. 3. Process according to claim 1, which comprises: mixing flour with the heavy centrifugate fraction by means of a suitable mechanical device; and washing the protein enriched kneaded dough thus prepared in a conventional washing device. 4. Process according to any of claims 1 to 3, which comprises: adjusting to a temperature of from 20 to preferably of from 25 to 45 0 C, the smooth, flowable flour/water mixture prepared wet-mechanically and further reduced and having a water/flour ratio of from 1.0 to preferably 1.0 to 5. Process according to any of claims 1 to 4, which comprises: 25 subjecting to a steady pause the smooth, flowable flour/water mixture prepared by wet-mechanical action, at a temperature of from 20 to 50 0 C, preferably of from to 45 0 C, the flour/water mixture being stirred moderately only and the length of the steady pause being from 5 to 120 minutes, preferably from 5 to 90 minutes.

6. Process according to any of claims 1 to 5, which comprises: treating the clump-free aqueous meal suspension in the centrifugal field of a helical-conveyor centrifuge at a specific clear surface load of 0.02 to 1.45 m preferably 0.1 to 0.4 m 3 of meal/water suspension per 100 m 2 of clear surface per hour.

45.M9S/bm -17- 69 9 9 C C 0 *trt: 1 :!3 "JI 4,' -iX31 b1 l ~-wI '4' Nf} 4 4 4 4- 7. Process for simultaneous recovery of wheat starch and wheat gluten substantially as herein described with reference to the drawings. 8. Process for simultaneous recovery of wheat starch and wheat gluten substantially as herein described with reference to the examples. DATED this 29th day of October. 1985 VE KOMBINAT STARKE AND KARTO'FFELVEREDLUNG By their Patent Attorneys GRIFFITH HASSEL FRAZER o 0 L 14 354 4589Sf bm -18- A