JPS6243652B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a method for converting a mixture of vital wheat gluten and wheat starch, such as wheat flour, into an active unmodified form of wheat gluten and a second product, used as such or further saccharified. The present invention relates to a method of processing to obtain solubilized starch for processing. It is known that wheat gluten loses its active properties when processed at high temperatures.
It is also known that wheat gluten has a tendency to become solubilized when exposed to hot water for an extended period of time. For these reasons, the application of conventional enzymatic solubilization methods to wheat flour (e.g. gelatinization, liquefaction and solubilization of the starch portion of flour with heat and liquefaction enzymes such as α-amylase) can lead to gluten denaturation and essentially causes solubilization. Furthermore, if the solubilized starch is saccharified by a saccharifying enzyme, a starch hydrolyzate is obtained, but the obtained hydrolyzate contains a large amount of solubilized gluten, and this is the final product. This makes purification (and especially decolorization) difficult and inoperable. Starch, or wheat flour, meal (grain meal),
Conventional methods for the enzymatic solubilization of starch-containing substances such as grits or the like involve preparing these aqueous slurries, in each case prior to the addition of the enzyme, or The use of α-amylase involves gelatinization of the starch by heating in the presence of the enzyme. These methods use high temperatures and, if used with ingredients containing active wheat gluten, will denature the gluten. α
-It has been known for a long time that amylase can solubilize starch under non-gelatinizing conditions, but the early conventional methods were unable to put this into practical use industrially. Ta. Wallerstein et al., in U.S. Pat. No. 2,583,451, disclose a method for converting pure starch to dextrose using alpha-amylase under non-gelatinizing conditions. In this method, the temperature should not exceed 45°C, the processing time is 48 to 72 hours, and the yield is very low, and this method is not suitable for use with gluten-containing starch raw materials. Processes have recently been developed that effectively hydrolyze granular starch without the customary gelatinization step, yet the remaining starch retains its granular form during hydrolysis. See, for example, Leach et al., U.S. Pat. Nos. 3,922,196 and 3,922,197;
No. 3922198, Hebeda et al.
No. 3,922,199 and U.S. Pat. No. 3,922,200 to Walon et al. Although these methods are highly effective for hydrolyzing starch and starch-containing substances, the conditions are such that when applied to flour, excessive solubilization and denaturation of the active gluten occurs. It is something. It is an object of the present invention to provide a method for processing wheat flour or the like to obtain starch, active gluten and starch hydrolyzate from the flour or the like. Another object of the invention is to carry out the enzymatic solubilization and, if desired, further enzymatic saccharification of the starch portion of the gluten-rich fraction of wheat flour, or of a mixture of wheat gluten and starch having other activities, so that the gluten is denatured. The solubilized (or saccharified) starch is substantially free of solubilized gluten;
The object is to provide a process which allows purification to be carried out by conventional and economical methods. According to the method of the invention, a mixture of active wheat gluten and starch is used in an aqueous suspension to kill bacterial α-
Using amylase, the starch is treated under conditions such that it is not gelatinized but is solubilized. In other words, during the solubilization process, the remaining starch remains granular, ie in a non-gelatinized form.
After solubilization of the starch, the still active unmodified form of gluten can be easily recovered by conventional methods such as filtration, decantation, centrifugation or using the hydroclone method. The solubilized starch solution is then concentrated and/or dried and further used with additional enzymes to generate saccharification products or as a substrate for additional starch hydrolysis as described below. It can be used. Specific conditions are described below. Although the invention can also be carried out with mixtures of starch and active gluten, the most obvious and practical starting material is wheat flour and the invention will therefore be described below with reference to the use of wheat flour. Describe it. The raw material used for enzymatic solubilization is a minimum of approx.
It must contain 25% protein by weight (dry basis), but preferably contains between 25 and 80% protein. If the starting material is protein 25
% or less, with the remainder being primarily starch, which may be acceptable due to the reaction conditions used, i.e. the ratio of water to protein, the time of the reaction, and the temperature. Such protein solubilization occurs. Flour is therefore first divided into two fractions: an essentially pure wheat starch fraction (which is of course also an important product) and a second fraction containing at least 25% (preferably 30-40%) gluten. must be divided into fractions. A second fraction is used in the method of the invention. The initial fractionation of the flour may be carried out in any manner, the only requirement being that the gluten is not denatured. Centrifugal decantation is one example of a method that can be used for this fractionation. into the aqueous slurry of the second gluten-rich fraction (preferably solids concentration 10-35% by weight);
Bacterial amylase, preferably essentially protease-free, is added and at a temperature not exceeding about 60°C (temperatures in the range of 45 to 60°C are preferred) and an optimum pH value for the enzyme to attack the starch. React with the enzyme for a short time (not more than about 6 hours). By this method essentially all (or as much as desired) of the starch is completely solubilized, the gluten is not denatured, and essentially no gluten dissolution occurs. Therefore, gluten, which is still active, as well as solubilized starch, which contains minimal amounts of solubilized protein, can be easily recovered. This solubilized starch is concentrated and/or dried and used as is or for any conventional saccharification process. Bacterial α-amylase is active at pH values ranging from about 4.0 to about 0.7 and at relatively low temperatures, i.e.
Those having significant activity at temperatures below 60°C are preferred. Preferred sources of such α-amylase are species of bacteria of the genus Bacillus, such as Bacillus subtilis, Bacillus licheniformis, Bacillus coagulans and Bacillus amyloliquefaciens. Australian Patent Application No. 4836/70 and US Pat. No. 3,697,378 describe suitable α-amylases. Bacillus described in the specification of an Australian patent application.
Amylases obtained from Licheniformis are particularly suitable. NCIB of Bacillus licheniformis strain
8061, NCIB8059, ATCC 6598, ATCC6634,
Particularly preferred are α-amylases obtained from ATCC 8480, ATCC 9945A and ATCC 11945. These are usually effective for liquefying granular starches. One such enzyme is commercially available under the trade name Thermamyl from NOVO Enteam Corporation, Mamaroneck, New York. Thermamil is characterized by the following properties: (a) It is thermally stable; (b) It is active over a wide range of pH values; and (c) Its activity and thermal stability are Less affected in the presence of calcium ions than other α-amylases. Representative analytical values for three different Thermamil formulations are shown below:

[Table] Other suitable α-amylases that can be used are shown below.

【table】

[Table] The α-amylase must be essentially free of protease activity to avoid excessive solubilization of gluten. Since virtually all commercially available α-amylase preparations have protease activity, the preparation must first be treated to be essentially protease-free. This can be easily achieved in the Thermamil formulation by heating the aqueous slurry of the enzyme formulation to 70-80°C for 30-45 minutes. The amount of α-amylase used must, of course, be sufficient to solubilize at least essentially all of the starch present, ie, at least about 0.1 active units per gram of starch (as used herein) -Amylase activity was measured as described in Leach et al., US Pat. No. 3,922,196). However, it is preferred to use even more than the minimum amount of α-amylase for two reasons. First of all, the excess amount of enzyme can accelerate the solubilization process, thereby further reducing the time that the gluten is processed under conditions that minimize solubilization of the gluten. Secondly, and still more importantly from an economic standpoint, the solubilized starch, which is present in the form of a dilute solution after separating the gluten fraction and still contains the active α-amylase, is added to this simply by adding new By adding raw material starch and, if necessary, adjusting the conditions for the best solubilization of newly added starch, it can be used directly as a medium for solubilizing additional starch. After solubilization of the additional starch, the product is of course combined with suitable enzymes, such as glucoamylase for producing glucose or glucose-containing hydrolysates, β-amylase (for example α-amylase for producing maltose syrup), etc.
The saccharification process is carried out using a specific suitable enzyme (with or without the use of a debranching enzyme such as 1-6 glucosidase). If it is ultimately not planned to use the saccharifying enzyme at any stage of the process, it may be advantageous to add it, or at least part of it, directly to the initial flour fraction together with the bacterial α-amylase. It is.
The presence of saccharifying enzymes in combination with α-amylase further acts to accelerate this solubilization step, with all the benefits associated with acceleration. As shown in the examples below, very practical systems for obtaining active gluten and starch hydrolyzate with any desired composition from wheat flour can be developed according to the invention, but these systems For example, wheat flour is first separated into a starch fraction and a gluten-rich fraction by a centrifugal gradient method, and then bacterial α-amylase is added to the gluten-rich fraction and only this fraction is treated with bacterial α-amylase. Sufficient amounts are added to solubilize not only the starch fraction, but also the starch obtained in the separation step, optionally with the addition of one or two saccharifying enzymes, and then the gluten-rich fraction is added. Treated according to the method of the invention, the active gluten is recovered and the starch obtained in the separation step is then added to the solubilized starch in the form of a dilute aqueous solution containing the active α-amylase and freshly Solubilizes the added starch,
It consists of saccharification if desired and finally purification of the hydrolyzate by conventional methods. This system can be designed to virtually eliminate wastewater treatment problems and be fully commercialized. Of course, the PH value in the solubilization method is determined by the α-
The operable range of amylase governs and it is preferred to use the enzyme's optimum PH. Most α-amylases exhibit their highest active site at about pH 6 (e.g. Thermamyl's optimum pH is
PH5 to 7, PH6 for rapitase, etc.). Saccharifying enzymes usually exhibit optimal activity at pH values lower than this (e.g. glucoamylase has a pH value of 4.0 to 4.5).
etc………). Therefore, when using saccharifying enzymes in combination with α-amylase during solubilization,
For those skilled in the industry, it is easy to determine the preferred PH value for this particular operation. The period must be sufficient to reach solubilization, but as short as possible to avoid over-solubilization of the gluten. The time required depends on various factors, such as the starch to be solubilized. , the type of α-amylase used, the presence or absence of saccharifying enzymes, the solids concentration, and the temperature.Times exceeding 6 hours should be avoided. use, an unacceptable amount of gluten solubilization occurs;
This reduces the yield of active gluten and colors the solubilized starch solution, making final purification difficult and requiring additional costs. Under most conditions solubilization is complete within the range of 1 to 3 hours, and these are the preferred reaction times. The solubilization temperature is preferably about 60°C, but temperatures as high as 45°C can also be used. Lower temperatures prolong solubilization time and should be avoided, and temperatures significantly higher than about 60° C. result in gluten denaturation. Any method can be used to bring the α-amylase-containing slurry to the solubilization temperature; however, if the temperature is raised too quickly from 50°C to the desired temperature, some denaturation of the gluten may occur.
This should therefore be avoided. Very satisfactory results are obtained when the temperature is increased to 50 to 60°C over a period of 10 minutes. The following examples are intended to illustrate the practice of the invention. In the examples, the Thermamil 60 α-amylase formulation was rendered essentially protease-free by heating the liquid formulation to 80° C. for 30 to 45 minutes. This treatment essentially results in complete inactivation of the protease without loss of α-amylase activity. Maxamil LX6000, its liquid enzyme formulation contains added calcium. Dissolved in low DE starch hydrolyzate solution (30% dry matter) and then heat treated to 75°C for 30 minutes. This treatment essentially destroys all proteases and 90% of alpha-amylase activity is retained. The percentages in the following examples and claims are percentages by weight unless otherwise specified. Example In this example, the gluten-rich fraction of wheat flour is
α-amylase and saccharifying enzyme (β-amylase)
The method is illustrated for solubilizing the gluten product, ultimately producing a highly concentrated maltose syrup, and recovering an additionally active gluten product. Soft flour (dry matter is 88.6% and contains 10.2% protein, 76.5% starch, 1.8% fat and about 0.4% each of ash and fiber) 1000Kg water 2000Kg
and this suspension is sieved to remove some coarse fibers. The suspension is stirred to keep the protein and starch components homogeneous, ie to prevent the gluten from agglomerating. The suspension was then transferred to an Alfa-Laval operating at a rotational speed of 2000 rpm.
Laval) is sent to a centrifugal decanter, where the output portion (protein-rich fraction) and bottom outflow portion (starch fraction) are collected. The bottom effluent, which in addition to starch contains 2.5% protein and some fiber and ash, is first passed through a series of ultracentrifugal decanters (2000 rpm) and then through a dehydration centrifuge. Purify and concentrate by
The excess cake is flash dried to reduce the moisture content to approximately 13%.
shall be. The product contains 98.7% wheat starch, 0.6% protein and 0.1% ash. The extravasation fraction has a dry matter content of 12% and contains 29.7% protein (by total Kjeldahl analysis) on a dry basis. The pH value of this was adjusted to 5.5 and 0.4% of protease-free bacterial α-amylase (Thermamil 60) and 0.06% of β-amylase (Biozyme M from Amano Chemicals) were added (dry based on total dry weight). 200 p.pm of CaCl ₂ are added and the temperature is then raised to 57° C. and maintained at that temperature for 2 hours. At the end of this period, 98.3% of the starch was solubilized. The product was passed through a shear press centrifuge operated at 12000 rpm, and the bottom runoff (gluten fraction) and overflow fraction (soluble starch fraction) were collected, respectively. The bottom outflow contains 35.6% dry matter and 68.2% protein on a dry basis. This is spray dried to a moisture content of 5.3% under the following conditions: Feed concentration: 35.6% Feed temperature: 45°C Inlet temperature: 161°C Discharge temperature: 88°C Gluten protein in the resulting dried product (68%)
still retains its original insolubility. The overflow consists of a dilute (7.6% dry matter) solubilized starch solution containing α-amylase, which still retains 90% of its original activity. This solution is enriched to 30% dry matter with previously recovered and dried wheat starch. PH
The temperature is adjusted to 6.0, the temperature is increased to 95°C, and the slurry is kept at this state until the starch is liquefied. The temperature is then lowered to 58° C., the pH value is adjusted to 5.0, and β-amylase is added thereto in an amount of 0.05% by weight (based on dry matter). The starch was saccharified under these conditions for 12 hours,
It is then purified using (a) 5% recovered carbon, (b) a strong cation exchange resin, (c) sulfonated carbon (Dusarit from Imacti), and (d) a weak anion exchange resin. The product is concentrated and then passed over 0.5% fresh carbon. The clear, water-like, colorless product has 43.7
DE, glucose content 3%, maltose content 55
%, tri- and higher grade saccharides 42%
has. EXAMPLE An aqueous slurry of soft flour is prepared as described in the example and mixed with Alfa-Laval.
Laval) Send to centrifugal decanter. This centrifugal decanter is a dry material containing 32.6% protein (dry basis).
Manipulate to produce 12.8% extravasation. The bottom runoff (starch fraction) is collected and processed as described in the example. Collect the overflow and divide it into three parts.
The symbols A, B, and C are attached, and the processing is performed as follows. A. Manufacture of maltodextrin - use of α-amylase alone for solubilization Increase the temperature to 60°C, adjust the pH number to 6.0, add Thermamil 60 α-amylase (without protease) to the total dry weight Add 0.3% by weight based on After a reaction time of 2 hours, 97.6% of the starch was solubilized. The product was collected using a shear press centrifuge (12000r.
pm) and the bottom effluent containing 36.7% dry matter containing 72% active gluten (dry basis) is spray dried as described in the example. The extravasation still contains 7.6% dry matter, including 90% active α-amylase, but this has been supplemented with new starch to reduce the dry matter content.
30%. Adjust the pH value to 6.0 and adjust the temperature to 94℃
cause it to rise. After a second reaction, the temperature was raised to 125°C to inactivate the enzyme,
The resulting starch-free solubilized maltodextrin with a DE of 18.6 is then purified in a conventional manner and spray-dried. B Dextrose production - α-amylase and glucoamylase are used for solubilization Adjust the pH value to 5.5 and add Thermamil 60
(0.25%) and glucoamylase (0.06%) enzymes (% of total dry weight) are added. The temperature is set to 60°C and kept at the same temperature for 90°C. The product was centrifuged as described in A,
Further, the bottom outflow portion is subjected to a second centrifugation to remove the accompanying solubilized starch, thereby obtaining a fraction rich in active gluten. The bottom effluent of the second centrifugation process contains 78% active gluten, which is then spray-dried as described in the Examples. The overflow from both centrifugation operations is combined. This fraction retains 90% of its original α-amylase activity, but only a small amount of glucoamylase activity remains. New starch was added to bring the dry matter content to 28.6%, and the PH
Adjust the titer to 6.0, raise the temperature to 95°C,
Keep at the same temperature until the starch is completely liquefied. Next, the temperature is lowered to 55°C, the pH value is adjusted to 4.2, and 0.04% glucoamylase is added thereto. After 33 hours of saccharification time, the product D.
E. is 97.6 and contains 94.8% dextrose. This was purified in conventional manner, crystallized and then dried to yield a 99.6% dextrose product. C. Manufacture of dextrose - use of α-amylase alone for solubilization In this case, treatment with α-amylase as in case A, centrifugation treatment, and removal of the bottom outflow portion containing gluten with 72% activity. Perform processing, etc. In addition, starch was newly added to the overflow portion containing 90% α-amylase to obtain a dry substance of 28.6%, and the temperature was raised to 95°C and kept at the same temperature until the starch was liquefied. The mixture was then cooled to 55° C., the pH value was adjusted to 4.8, glucoamylase was added thereto in an amount of 0.7%, and the product was saccharified as described in B to obtain dextrose. Example In this example, three different attempts were made. These are labeled A, B, and C. In each of these tests, flour containing 11% protein was suspended in water and fractionated using an Alfa Laval centrifugal decanter as described in the examples above. A bottom runoff fraction (starch) and (2) an overflow fraction (protein-rich fraction) having the following composition are obtained: Total weight 1777.5Kg Dry matter% 16 Dry matter weight 284.4Kg Protein% (dry matter) Quantity basis) 33.65 Protein weight 95.7Kg Each protein-rich fraction was treated with bacterial α-amylase for 4 hours at a pH value of 6 and 60°C.
Treatments were carried out using different enzyme preparations as described below. A: Maxamil LX6000 (Bacillus
subtilis and treated to be essentially protease-free) was added in an amount of 0.25% based on total dry weight. B: 0.5 Thermamil 60 (without protease)
It was added in an amount of %. C: Thermamil 60 (without any treatment to make it essentially protease-free) was added in an amount of 0.5%. After processing, the products are separated using a Toniatti centrifuge operating at 25000 rpm. The bottom runoff (active gluten) and spillover (soluble starch) fractions of each have the compositions shown in the table.

[Table] The above values indicate that it is desirable to use α-amylase, which essentially does not contain protease, when the solubilization of gluten is to be minimized.

Claims (1)

[Claims] 1. Processing a mixture of active wheat gluten and wheat starch containing at least about 25% protein,
In separating the active gluten and obtaining the solubilized starch as a second product, the mixture is prepared in an aqueous medium in order to solubilize a substantial amount of the starch without gelatinization. , bacterial α-amylase was allowed to act under conditions such that the solubilization temperature was in the range of 45 to 60°C, the pH value was in the range of about 5 to about 7, and the treatment time did not exceed about 6 hours. ,
A method for treating the above-mentioned mixture, characterized in that active gluten is then separated from the solubilized starch. 2. The method according to claim 1, wherein the α-amylase is essentially protease-free. 3. The method according to claim 1 or 2, wherein the active mixture of wheat gluten and wheat starch consists of a protein-rich fraction obtained from wheat flour. 4 Approximately 25 to 80% of the protein-rich fraction
4. The method according to claim 3, which comprises the protein of claim 3. 5 Approximately 30 to 40% fraction is rich in protein
5. The method according to claim 4, which contains a protein. 6 The protein-rich fraction is obtained by centrifugation and decantation of an aqueous flour slurry to separate the flour into a protein-rich fraction and a second fraction consisting essentially of protein-free wheat starch. The method according to any one of claims 3 to 5, which is obtained by. 7. The method according to any one of claims 1 to 6, wherein the bacterial α-amylase is essentially protease-free and obtained from a bacterium of the genus Bacillus. 8. The method according to claim 7, wherein the α-amylase is obtained from a bacterium selected from the group consisting of Bacillus licheniformis and Bacillus subtilis. 9. Bacterial α-amylase is added in an amount in excess of the minimum amount required to solubilize all the starch present, and the solubilization time does not exceed about 3 hours. to the method described in any one of paragraphs 8 to 8. 10 In processing a mixture of active wheat gluten and wheat starch containing at least about 25% protein to separate the active gluten and obtain solubilized starch as a second product, the mixture is In order to solubilize a substantial amount of starch in the medium without gelatinization, the solubilization temperature is in the range of 45 to 60°C, the pH value is in the range of about 5 to about 7, and Bacterial α-amylase is allowed to act under conditions such that the treatment time does not exceed about 6 hours,
A method for treating the above-mentioned mixture, characterized in that active gluten is then separated from the solubilized starch, and the obtained solubilized starch is saccharified with a saccharifying enzyme. 11. The method according to claim 10, wherein the saccharifying enzyme is glucoamylase. 12. The method according to claim 10, wherein the saccharifying enzyme is a maltogenic enzyme. 13 A. fractionating wheat flour and separating it into a first fraction containing essentially pure wheat starch and a second protein-rich fraction containing at least 25% protein; B. the starch portion of the second fraction; (1) to solubilize in the aqueous slurry not only the starch present in this fraction, but also at least a large portion of the wheat starch obtained as the first fraction of step A; (2) adding a sufficient amount of protease-free bacterial alpha-amylase;
C. Separate and recover active gluten from the resulting solubilized starch solution; D. Separate and recover the wheat starch obtained as the first fraction of step A. containing an enzyme that is at least largely still active;
A method for treating wheat flour, comprising: adding E to the solubilized starch solution, and allowing the resulting mixture to be solubilized by an active enzyme contained in the solubilized starch solution. 14 In step B, the aqueous slurry contains bacteria α
- The method according to claim 13, wherein a saccharifying enzyme is added in addition to amylase. 15. The method according to claim 13, wherein the bacterial α-amylase is obtained from a microorganism selected from the group consisting of Bacillus licheniformis and Bacillus subtilis. 16. The method according to claim 13, wherein the wheat flour is separated by centrifugation and decantation. 17. Claim 13, wherein wheat flour is fractionated into a first fraction containing essentially pure wheat starch and a second protein-enriched fraction containing about 30 to about 40% protein. Method described. 18 A. fractionating wheat flour and separating it into a first fraction containing essentially pure wheat starch and a second protein-rich fraction containing at least 25% protein; B. the starch portion of the second fraction; (1) to solubilize in the aqueous slurry not only the starch present in this fraction, but also at least a large portion of the wheat starch obtained as the first fraction of step A; (2) adding a sufficient amount of protease-free bacterial alpha-amylase;
C. Separate and recover active gluten from the resulting solubilized starch solution; D. Separate and recover the wheat starch obtained as the first fraction of step A. containing an enzyme that is at least largely still active;
E solubilizing the resulting mixture by an active enzyme contained in the solubilized starch solution;
and F. A method for processing wheat flour, which comprises saccharifying the solubilized starch obtained in step E with an enzyme. 19. The method according to claim 18, wherein the enzymatic saccharification is carried out using glucoamylase. 20. The method according to claim 18, wherein the enzymatic saccharification is carried out using a maltogenic enzyme. 21 In step B, the aqueous slurry contains bacteria α
- The method according to claim 18, wherein a saccharifying enzyme is added in addition to amylase. 22. The method of claim 18, wherein the bacterial α-amylase is obtained from a microorganism selected from the group consisting of Bacillus licheniformis and Bacillus subtilis. 23. The method according to claim 18, wherein the wheat flour is separated by centrifugation and decantation. 24. Claim 18, wherein wheat flour is fractionated into a first fraction containing essentially pure wheat starch and a second protein-enriched fraction containing about 30 to about 40% protein. Method described.