FI63255B - FOERFARANDE FOER SEPARERING AV VITALT VETEGLUTEN OCH SOLUBILISERAD VETESTAERKELSE FRAON VETEMJOEL - Google Patents

Description

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Patent »och ragitterstyralaan '' Amok» utii (d oeh utUkrtun pubiieund 31.01.83 (32) (33) (31) Pyy4 «tty * Tuoik * u * —Begird Priority 01.11.76 United States , Inc., International Plaza, Englewood Cliffs, New Jersey 07632, USA (72) Raoul Guillaume Philippe Walon, Brussels, Belgium-Belgium (BE) (7I +) Oy Kolster Ab (5I +) Method for separating vital wheat gluten and soy-stabilized wheat starch wheat flour - Förfarande för separering av vitalt vetegluten och solubiliserad vetestärkelse frän vetemjöl

The invention relates to a process for separating vital wheat gluten and solubilized wheat starch from wheat flour, after which the solubilized starch is optionally converted into sugar.

It is known that wheat gluten loses its "viable" properties at high temperatures and tends to dissolve upon contact with warm water for extended periods of time. For these reasons, the use of a conventional enzymatic dissolution method, i.e., gelling and dissolving the starch portion of flour with heat and a dissolving enzyme such as alpha-amylase, results in a change in the nature of gluten and its dissolution.

In addition, if the dissolved starch is converted to sugar by a saccharification enzyme to prepare a starch hydrolyzate, the resulting hydrolyzate contains a large amount of dissolved gluten, and this makes final purification (and especially decolorization) of 2 63255 difficult and impractical.

In conventional methods for the enzymatic dissolution of starch or starch-containing substances such as flour, coarse flour, "grits", etc., the starch is gelled by heating its aqueous slurry either before the addition of the enzyme, or if high temperature alpha-amylase is used in the presence of the enzyme. It has long been known that alpha-amylases are capable of dissolving starch under non-gelling conditions, but methods known in the art have never been commercially available., Wallerstein et al., U.S. Pat. for the conversion of pure starch to dextrose by alpha-amylase under non-gelling conditions, in which the temperature does not exceed 45 ° C, the processing times are 48 to 72 hours and the yields are very low, and the process is not suitable for gluten in the case of a starch product containing

Previous methods have been developed to efficiently hydrolyze granular starch without a conventional gelling step, as a result of which the starch remaining during hydrolysis retains its granular form (e.g., U.S. Patent Nos. 3,922,196, 3,922,197, 3,922,198, 3,922,199 and 3,922,199). . These methods are very effective in hydrolyzing starch and starch-containing substances, but under these conditions, the use of wheat flour results in excessive dissolution of vital gluten and a change in nature.

The method according to the invention is characterized in that the method comprises the following steps; (1) separating the wheat starch from the flour, leaving a gluten-rich fraction with at least 25% by weight of protein, (2) solubilizing the starch in the gluten-rich fraction without causing it to gelatinize by treating the gluten-rich fraction as an aqueous suspension with bacterial alpha practically free of protease, at 45-60 ° C at 3 63255 and pH 5-7, the amount of enzyme used being at least sufficient to solubilize all the starch in the fraction, and possibly more than this amount, and the treatment -time sufficient to solubilize at least 95% of the starch, but not exceeding 6 hours, (3) vital gluten is separated from the solubilized starch and recovered, (4) with the remaining solubilized starch solution still containing active alpha-amylase, said fresh starch is optionally added un solution and allowing the starch to be solubilized by alpha-amylase, and (5) the solubilized starch is optionally enzymatically converted to sugar.

According to the method of the invention, a mixture of vital wheat gluten and starch is treated in an aqueous suspension with bacterial alpha-amylase under conditions in which the starch dissolves without gelling. In other words, during dissolution, the residual starch is kept in a granular, i.e. non-gelled, form. After dissolving the starch, the gluten, which is still in vital and unchanged form, can be easily recovered by conventional methods such as filtration, decanation, centrifugation or using hydrocyclones. The dissolved starch solution can then be concentrated and / or dried, further enzymatically treated to form sugared products, or, as described later, used as a substrate for the hydrolysis of additional starch. The specific conditions are described below.

Although the invention can be practiced with any mixture of starch and vital wheat gluten, the most practical starting material is wheat flour; therefore, the invention will now be described as applied to wheat flour. The starting material to be subjected to enzymatic dissolution should contain at least about 25% protein (by dry weight), with a protein content of between 25-80% being suitable. If the starting material contains less than 25% protein, with the remainder being predominantly starch, excessive dissolution of the protein occurs due to the reaction conditions used, i.e., the ratio of water to protein and reaction time and temperature. Therefore, wheat flour should first be divided into two fractions, one of which is practically pure wheat starch (which in itself is a valuable product) and the other fraction contains at least 25% (preferably 30-40%) gluten. The method of the invention is then applied to a gluten-rich fraction. The initial fractionation of the flour can be carried out in any way, the only requirement being that the gluten does not change in nature, e.g. by centrifugation.

To the aqueous suspension of the gluten-rich fraction (dry matter content preferably 10-35% by weight) is added bacterial alpha-amylase, which contains practically no protease, and the enzyme is allowed to react with the starch for a short time (not more than about six hours). At a temperature of -60 ° C at a pH of 5-7, which is optimal for the action of the enzyme on starch. With this method, virtually all (or as much as desired) of the starch is completely soluble, gluten does not change in nature, and substantial dissolution of gluten does not occur. Therefore, vital gluten as well as dissolved starch containing a small amount of dissolved protein can be easily recovered. Dissolved starch can be concentrated and / or dried and used "as is" or converted into sugar in any conventional manner.

The bacterial alpha-amylase is preferably active in the pH range of about 4.0 to about 7.0, and has considerable activity at relatively low temperatures, i.e., 60 ° C and below. Preferred sources of such alpha-amylases are certain species of the microorganism Bacillus, namely B. subtilis, B. licheniformis, B. coagulans and B. amyloliquefaciens. Suitable alpha-amylases are described in AT Patent Application No. 4836/70 and U.S. Patent No. 3,697,378. Particularly preferred amylases are those derived from B. licheniformis, as described in said AT patent application. Particularly preferred is alpha-amylase derived from B. licheniformis strain NCIB 8061, NCIB 8059, ATCC 6598, ATCC 6634, ATCC 8480, ATCC 9945A and ATCC 11945. They are exceptionally effective in solubilizing granular starch. One such enzyme is known under the trade name "Thermamyl" (NOVO Enzyme Corporation, Mamaroneck, New York). "Thermamyl" has the following properties: 63255 a) it is heat resistant; b) it is active over a wide pH range; and c) its activity and heat resistance are less dependent than the presence of added calcium ion of other alpha-amylases.

Typical analyzes of the three different Thermamyl products are as follows:

Thermamyl 60 Thermamyl 120 Thermamyl Dry matter content,% 35.4 98.8 94.6

Alpha-amylase activity U / g 1156.0 2105.0 9124.0

Protein,% of dry matter 26.5 21.2 21.2

Ash,% of dry matter 60.1 91.2 64.4

Calcium,% of dry matter 0.04 0.72 4.9

Sodium,% of dry matter 12.3 12.2

Other suitable alpha-amylases that are commercially available include:

Table I

Enzyme preparation Company Form Activity

Rhozyme H-39 Rohm & Haas powder 4.874 U / g

Takamine HT-1000 Miles Powder 3.760 U / g

Tenase Miles is 2.043 U / ml

Dex-Lo MM Wallerstein fluid 1.213 U / ml

Novo SP-96 Novo powder 7.310 U / g

Novo B, Subtilis Novo fluid 1.599 U / ml

Kleistase GM-16 Daiwa Kasai Powder 26,593 U / g

Kleistase L-I Daiwa Kasai neste 1,918 U / ml

Rapidase SP-25Q Societe Rapidase powder 11.655 U / g

france

Maxamyl LX6000 Gist-Brocades fluid 13,300 U / ml

Alpha-amylase should have virtually no protease activity to avoid excessive dissolution of gluten; however, since all commercially available alpha-amylase preparations contain protease activity, it is necessary to first treat the preparation to remove the protease. This can be easily accomplished with Thermamyl preparations by heating an aqueous suspension of the enzyme preparation at 70-80 ° C for 30-45 minutes.

The amount of alpha-amylase used should be sufficient to dissolve at least substantially all of the starch present, i.

6 63255 at least about 0.1 activity units per g of starch. (Alpha-amylase activity, as used herein, is determined by the method of Leach et al., U.S. Patent 3,922,196). However, it is preferred to use more than the minimum amount of alpha-amylase for two reasons. First, the excess enzyme accelerates the dissolution process, thus reducing the time gluten is exposed to dissolution. Another and very important advantage from an economic point of view is that after separation of the gluten fraction, the dissolved starch present in the form of a dilute solution containing active alpha-amylase can be used directly as a medium to dissolve the additional starch simply by adding fresh crude starch and adjusting the conditions. for optimal dissolution. After dissolving the additional starch, the product can be converted to sugar by a suitable enzyme, e.g. exo-1,4-o (-glucosidase for the preparation of dextrose or dextrose-containing hydrolysates, with beta-amylase (with or without enzyme, e.g. alpha-1-6-glucosidase). ) for the preparation of maltose syrups, etc. If a saccharifying enzyme is to be used at some stage in the process, it is preferable to add it, or at least a part thereof, directly to the initially obtained flour fraction together with bacterial alpha-arylase.

The pH of the leaching process is determined by the operating range of the alpha-amylase used and the use of the optimum pH of the enzyme is preferred. The optimal activity of most alpha-amylases is at about pH 6 (the optimum for Thermamyl is pH 5-7, for Rapidane pH 6, etc.). Optimal activity of sugar-converting enzymes is usually achieved at lower pH values (e.g., pH 4.0-4.5 for exo-1,4-O 2 -glucosidase). If a sugar-converting enzyme is used in combination with alpha-amylase during dissolution, it may be desirable to use a pH between these optimum.

The dissolution time must be sufficient for the desired amount of starch to dissolve, but should be as short as possible to avoid excessive dissolution of gluten. The time required depends on various factors, e.g., the amount of starch to be dissolved, the amount and type of alpha-amylase used, the dry matter content and temperature, and whether or not the sugar-converting enzyme is present. Periods of more than six hours should be avoided as they result in the dissolution of too much gluten, which lowers the yield of vital gluten and causes so much discoloration in the dissolved starch solution that final purification becomes difficult and expensive. Under most conditions, dissolution can be completed in 1-3 hours and this is a preferred time.

The preferred dissolution temperature is about 60 ° C, but can be as low as 45 ° C. Lower temperatures prolong the dissolution time, and temperatures well above 60 ° C cause a change in the nature of gluten.

The alpha-amylase-containing suspension can be brought to the dissolution temperature in some conventional manner, but too rapid a rise in temperature from 50 ° C to the final temperature may cause some change in the nature of the gluten and should be avoided. Raising the temperature from 50 ° C to 60 ° C in 10 minutes is completely satisfactory.

The following examples are intended to illustrate the invention in practice. In the examples, the protease was removed from Thermamyl 60 alpha-amylase by heating the liquid commercial preparation for 30-45 minutes at 80 ° C. This treatment resulted in complete inactivation of the protease without substantially losing alpha-amylase activity. Maxamyl LX6000 was treated by first dissolving a liquid commercial enzyme preparation in a low-D.E. starch hydrolyzate solution (30% dry matter) to which calcium had been added and heating at 75 ° C for 30 minutes.

This treatment abolished virtually all of the protease, and 90% of the alpha-amylase activity was retained.

In the examples and claims, all percentages are by weight unless otherwise indicated.

Example I

This example illustrates the dissolution of a gluten-rich fraction of wheat flour with alpha-amylase and a sugar-converting enzyme (beta-amylase) and the final preparation of a maltose-rich syrup in addition to the recovery of the vital gluten product.

1000 kg of soft wheat flour (with a dry matter content of 88.6% and containing 10.2% protein, 76.5% starch,], 8% fat and about 0.4% ash and about 0.4% fiber ) was suspended in 8 63255 in 2000 kg of water and the suspension was screened to separate the coarse fibers. The suspension was mixed to keep the protein and starch components in a homogeneous state, i.e. to prevent gluten agglomeration. The suspension was then fed to an Alfa-Laval centrifugal decanter operating at 2000 rpm, and the upstream (protein-rich fraction) and downstream (starch fraction) were collected. Downstream, which contained approx.

2.5% protein and some fiber and ash in addition to starch were then purified and concentrated by passing it first through centrifugal decanters (2000 rpm) and then through a dewatering centrifuge. The filter cake was quickly dried to a moisture content of about 13%. The product contained 98.7% wheat starch, 0.6% protein and 0.1% ash.

The upstream fraction had a dry matter content of 12% and contained 29.7% protein (total Kjeldahl) in the dry matter. The pH was adjusted to 5.5 and 0.4% protease-free bacterial alpha-amylase (Thermamyl 60) and 0.06% beta-amylase (Biozyme M from Amano Chemicals) (based on total dry weight) were added. 200 ppm (parts per million) CaCl 2 was also added and the temperature was raised to 57 ° C and held for two hours. During this time, 98.3% of the starch dissolved.

The product was fed through a Sharples centrifuge operating at 12,000 rpm and collecting downstream (gluten fraction) and upstream (soluble starch fraction).

The downstream dry matter content was 35.6% and contained 68.2% protein based on dry matter. It was spray dried to a moisture content of 5.3% under the following conditions:

Feed content: 35.6%

Feed temperature: 45 ° C

Inlet temperature: 161 ° C

Outlet temperature: 88 ° C

The gluten fraction (68%) of the dry product obtained had retained its original insolubility.

The overflow comprised a solution of dilute (7.6% dry matter) dissolved starch containing alpha-amylase; alpha-amylase had retained 90% of its original activity. This solution was enriched with previously recovered and dried wheat starch to a dry matter content of 30%. The pH was adjusted to 63255 6.0, the temperature was raised to 95 ° C and the suspension was maintained at this temperature until the starch had dissolved.

The temperature was then lowered to 58 ° C, the pH was adjusted to 5.0 and beta-amylase was added in an amount of 0.05% by weight (based on dry matter). The starch was converted to sugar under these conditions for 12 hours, after which the product was purified with (a) 0.5% carbon, (b) strong cation exchange resin, (c) sulfonated carbon ("Dusarit", manufactured by Imacti), and (d) weak anion exchange resin. . The product was concentrated and fed to 0.5% pure carbon. The bright, water-white product D.E. was 43.7, dextrose content 3%, maltose content 55% and tri- and higher saccharide content was 42%.

Example II

An aqueous suspension of soft wheat flour was prepared as in Example I and passed to an Alfa-Laval centrifugal actuator. A centrifugal decoder was used to obtain an upstream stream with a dry matter content of 12.8% and a protein content of 32.6% based on dry matter.

The downstream (starch fraction) was collected and treated as in Example I.

The upstream stream was collected and divided into three sections, labeled A, B, and C, and treated as follows.

A. Preparation of malto-dextrin - use of alpha-amylase alone for reconstitution The temperature was brought to 60 ° C, the pH was adjusted to 6.0 and Thermamyl 60 alpha-amylase (protease-free) was added in an amount of 0.3% by weight, calculated of the total dry weight. After a reaction time of 2 hours, 97.6% of the starch had dissolved.

The product was centrifuged in a Sharples centrifuge (12,000 rpm) and a downstream stream with a dry matter content of 36.7% and containing 72% vital gluten (dry matter) was spray dried as in Example I.

The upstream stream, with a dry matter content of 7.6% and still containing 90% active alpha-amylase, was enriched with fresh starch to a dry matter content of 30%. The pH was adjusted to 6.0 and the temperature was adjusted to 94 ° C. After a reaction time of 2 hours, the temperature was raised to 125 ° C to inactivate the enzyme, followed by the product, starch-free soluble maltose dextrin, which D.E. was 18.6, was purified and spray dried by conventional methods.

B. Preparation of dextrose - use of alpha-amylase and exo-1,4-o (glucosidase) for dissolution The pH was adjusted to 5.5 and Thermamyl 60 enzymes (0.25%) and glucoamylase enzymes (0.06% ) (percent of total dry weight) The protease was removed from Thermamyl 60 by the method described in the fourth paragraph on page 7. The temperature was raised to 60 ° C and maintained for 90 minutes.

The product was centrifuged as in A, after which the downstream was centrifuged a second time to remove excess soluble starch and to obtain a fraction with more vital gluten. Downstream of the second centrifugation, which contained 78% vital gluten, was spray dried as in Example I.

The upstream streams from both centrifugations were pooled, the alpha-amylase activity in this fraction was 90% of the original, but very little exo-1,4- <X-glucosidase activity remained. Fresh starch was added to a dry matter content of 28.6%, the pH was adjusted to 6, and the temperature was raised to 95 ° C and maintained there until the starch was completely dissolved.

The temperature was lowered to 55 ° C, the pH was adjusted to 4.2 and 0.04% exo-1,4-α-glucosidase was added. After a conversion time of 33 hours into sugar, the D.E. was 97.6 and contained 94.8% dextrose. It was purified, crystallized and dried in a conventional manner to a 99.6% internal dextrose product.

C. Preparation of Dextrose - Use of Alpha-Amylase for Dissolution Alone This section was treated with alpha-amylase as Part A, comprising centrifugation and treatment of downstream containing 72% vital gluten.

Fresh starch was added to the upstream stream (still containing 90% alpha-amylase) to a dry matter content of 28.6% and the temperature was raised to 95 ° C and maintained until the starch was dissolved. It was cooled to 55 ° C and the pH was adjusted to 4.8, glucoamylase was added in 0.7% amount and the product was dextrose as in B to give a product similar to B.

63255 11

Example III

In this example, three separate experiments were performed, labeled A, B, and C. In each experiment, wheat flour containing 11% protein was suspended in water and fractionated as in the previous examples with Alfa-Laval centrifugal decanters to give (1) a downstream fraction (starch fraction) which was recovered as in the previous examples and (2) an upstream and protein-rich fraction) with the following composition:

Total weight 1777.5 kg

Dry matter content% 16

Weight, dry matter 284.4 kg

Protein,% dry weight 33.65

Protein weight 95.7 kg

Each protein-rich fraction was treated with bacterial alpha-amylase at pH 6 and 60 ° C for four hours, with the differences between the different experiments in the preparation of the enzyme used as follows. A: Maxamyl LX6000, derived from protease-depleted Bacillus subtilis as described on page 7, fourth paragraph, was added in an amount of 0.25%, based on total dry weight. B: Thermamyl 60 (protease free) was added in an amount of 0.5%. C: Unprotected Thermamyl 60 was added in an amount of 0.5%.

After treatment, each product was separated by the Toniatti centrifugal method at 25,000 rpm. The corresponding downstream fraction (vital gluten) and upstream fraction (soluble starch) had the compositions shown in Table II.

12 63255

Table II

A B C

Downstream (vital gluten fraction):

Total weight 578.3 kg 561.5 kg 467.3 kg

Dry matter content,% 26.8% 23.4% 27.6%

Dry matter weight 155 kg 131 kg 129 kg

Protein,% of dry matter 55% 65% 53.7%

Protein weight 85.25 kg 85.15 kg 62.97 kg

Upstream (soluble starch fraction):

Gross weight 1431.7 kg 1448.5 kg 1542.7 kg% dry matter 8.9% 10.5% 10.1%

Dry matter weight 129.4 kg 152.1 kg 155.8 kg

Protein,% 8.1% 6.8% 16.9%

Protein weight 10.3 kg 10.3 kg 26.3 kg

It appears from the above values that alpha-amylase, which contains virtually no protease, preferably reduces gluten dissolution.

Claims (11)

A process for separating the vital wheat gluten and solubilized wheat starch from wheat flour, whereupon the solubilized starch is optionally converted into sugar, characterized in that the process comprises the following steps: (1) the wheat starch is separated from the flour, leaving a gluten rich, contains at least 25% by weight of protein, (2) the starch of the gluten-rich fraction is solubilized without effecting gelatinization thereof by treating the gluten-rich fraction as an aqueous suspension with bacterial alpha-amylase, which contains virtually no protease at all at a temperature of 45-60 ° C and at a pH of 5-7, wherein the amount of enzyme used is at least sufficient to solubilize all starch in the fraction, and possibly greater than this amount, and wherein the treatment time is such that is sufficient for solubilization of at least 95% of the starch, but not exceeding 6 hours, (3) the vital gluten (4) if the residual solubilized starch solution still contains active alpha-amylase, any fresh starch is added to said solution, where possibly enzymatic til sugar. 2. A process according to claim 1, characterized in that the gluten-rich fraction contains 25-80% protein. 3. A process according to claim 1 or 2, characterized in that the gluten-rich fraction contains about 30 - about 40% protein. 4. A process according to any one of claims 1-3, characterized in that the gluten-rich fraction is obtained by centrifugal decanting of an aqueous slurry of wheat flour and the flour is thereby separated into the gluten-rich fraction and a second fraction containing practically protein-free wheat starch. 5. A method according to any one of claims 1-4, characterized in that the bacterial alpha-amylase is obtained from a Bacillus microorganism. 6. A process according to claim 5, characterized in that the alpha-amylase is obtained from the microorganism Bacillus licheniformis or Bacillus subtilis. Process according to any of claims 1-6, characterized in that the bacterial alpha-amylase is added in excess relative to the minimum amount needed to solubilize all of the starch and the dissolution time does not exceed 3 hours. Process according to any one of claims 1-7, characterized in that the gluten-rich fraction is treated by (A) adding to it an aqueous slurry of a protease-free bacterial alpha-amylase in an amount sufficient to dissolve only starch present in this fraction but also at least a substantial portion of the wheat starch initially separated from the wheat flour, subjecting said gluten-rich fraction to the action of the enzyme at a temperature of 45 ° C-60 ° C and at a pH of 5-7 time period not exceeding about 3 hours, after which (B) separates and utilizes the vital gluten from the resulting solution of solubilized starch; (C) adding at least a substantial portion of the hydrogen starch, initially separated from the hydrogen flour, to the solution of the solubilized starch, which solution contains active bacterial alpha-amylase; (D) solubilizes the obtained mixture by means of active enzymes which are part of the solution of the dissolved starch, and (E) optionally convert the solubilized starch obtained in step (D) enzymatically to sugar. 9. A process according to any one of claims 1-8, characterized in that the enzymatic conversion to sugar is carried out by means of exo-1,4-oC-glucosidase. Process according to any of claims 1-8, characterized in that the enzymatic conversion to sugar is carried out by means of a maltogenic enzyme. Process according to any of claims 8-10, characterized in that in step (A) a tili sugar converting enzyme is added to the aqueous slurry in addition to bacterial alpha-amylase.