JPS6228655B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for removing extraneous substances from vegetable protein materials. The production of vegetable protein isolates involves initially solubilizing a large portion of the protein fraction of the starting material, such as soybean flour or soybean flakes. Solubilization of the protein is followed by acid precipitation of the solubilized protein, followed by washing to produce a "purified" form of the protein, commonly referred to as a protein isolate. The precipitated protein fraction usually has a protein content in excess of 90% by weight on a dry basis and has found widespread use as a food ingredient due to its active and nutritional properties. The improved activity of these protein isolates in various food applications has led to the use of isolated proteins in U.S. Pat.
It can also be obtained by further processing as described in No. 3694221. Residues from solubilization of protein fractions have heretofore been regarded as by-products of the isolation process of limited utility. Typically,
This residue is referred to as the "spent flake" fraction and contains primarily fibrous portions of the starting material with a certain residual amount of unextracted protein. Typically and by way of example, about 57 in the starting material
In terms of % protein (dry basis) values, exhaustive extraction of aqueous alkaline soluble substances can be carried out until the extracted product or residue contains only 10-45% protein on a dry basis. Therefore, it is clear that unextracted protein exists in the residue, and it seems that it has the potential as a useful food ingredient. One of the greatest problems in further processing residue or "waste" flakes is the removal of extraneous material from the "waste" flake fraction. The starting material, such as soybean flour or flakes, contains a certain amount of waste or extraneous particulate matter that is not removed during processing of the raw soybean. This waste includes stems, pods, tenons and shells from the soybeans themselves, or seeds of various weeds and plants that have been processed with the soybeans, as well as completely unrelated materials such as dirt, sand, etc. Needless to say, since these extraneous substances are insoluble, they do not interfere with the solubilization step for removing protein fractions. This is because these materials are retained together with the insoluble residue or waste flake fraction. However, the presence of this extraneous material in the waste flake fraction compromises its usefulness as a food ingredient. The presence of extraneous material in the waste flake fraction is considered a black stain, and removal of this extraneous material should result in a product with improved color and flavor properties that can be used as a food ingredient. It would therefore be highly desirable to provide a means of removing extraneous materials from the residues of plant protein materials, particularly extracted plant protein materials, to significantly improve their potential as food ingredients. Accordingly, it is an object of the present invention to provide a method for removing extraneous materials from plant protein materials. It is also an object of the present invention to provide a method for removing extraneous materials from aqueous and/or aqueous alkaline extracted plant protein materials. It is also an object of the present invention to provide a method for removing extraneous matter from a vegetable protein starting material to produce a waste flake fraction with improved color and flavor properties. Furthermore, it is an object of the present invention to obtain proteins from waste flake fractions of extracted vegetable protein substances having improved white color with high functionality as food ingredients;
To provide a fibrous product. These and other objects are achieved in the present invention by a method for removing extraneous materials from plant protein materials. This method can be applied to extraction residues derived from the solubilization of plant protein materials or protein fractions of protein solubilization steps for the production of protein isolates. According to the invention, (a) a slurry of plant protein solid material is formed having a solids content of 2 to 10% by weight and containing solid material unrelated to the plant protein material; (b) said slurry is (c) separating said slurry by continuous centrifugation at ~50000 G-sec into a fraction consisting of a slurry of said plant protein solid material and a fraction containing said unrelated solid material in concentrated form; (c) then said plant protein solid material; A method for removing extraneous solid material from a plant protein material is provided, the method comprising: collecting a fraction consisting of a slurry of a plant protein material. As previously mentioned, the method of the invention can be applied to the starting material during the initial protein isolation or preferably to the waste flake fraction obtained from the isolation process. In this way, extraneous materials such as debris from soybean plants and other undesirable materials such as mud,
Separation of sand etc. has been found to be an essential step in obtaining improved color and flavor vegetable protein products from waste flake fractions. Waste flake fraction was generally considered to be a by-product of plant protein isolate processing with limited utility as a food ingredient. Conventional methods for producing protein isolates also include centrifugation of waste flake fractions or aqueous alkaline extracts; centrifugation is used to dehydrate the extracted material to increase solids content for drying purposes used only for However, as mentioned above, the type of centrifugation conditions used for dehydration retains extraneous matter found in the raw soybean, such as dirt, sand, and debris, thereby significantly reducing the usefulness of the resulting product as a food ingredient. It was restricting. In this regard, centrifugation conditions for dewatering a slurry of plant protein material are intended to concentrate the solids of the slurry for drying, and typically these conditions require that the centrifuge remove as much of the product as possible. It involves operating under conditions of relatively high G forces for a period of time sufficient to concentrate to a high solids content. If a centrifugation step is also used prior to dehydration under conditions such that the plant protein material is retained in slurry form but only extraneous matter is concentrated, subsequent dehydration produces a product with highly desirable color properties. It was determined that things would be obtained. The conditions as defined below in the present invention include centrifugation power and time below which only extraneous matter is concentrated, thereby leaving the plant protein material or fraction in slurry form to be concentrated during the dehydration process. It also includes adjustment to a certain degree. Extraneous plant protein substances
The method of the present invention for removing matter is generally applied to a variety of materials used or obtained in conventional protein isolate processing. The starting material for producing soybean isolates is typically defatted and desolvated meal, flour, or flakes prepared from soybeans. Defatting or removing oil fractions from soybeans is accomplished in a conventional manner using hexane or other hydrocarbon solvents. The solvent extracted product is desolvated by conventional methods known to those skilled in the art. The resulting dehulled, defatted, desolvated soy flour or flakes typically have a high dispersible protein content useful in plant protein isolate production processes. The conventional method for producing plant protein isolates, such as soybean isolates, is to first treat soybean flour or flakes with an aqueous or aqueous alkaline agent to extract bulk soluble proteins and carbohydrates or other aqueous alkaline soluble substances from the defatted flakes. Affects solubilization and removal. Any suitable aqueous alkaline solvent can be used for this purpose. The extraction process may be carried out in one step, or may include two or more steps as desired,
One of these processes involves the use of an alkaline-free aqueous medium as the extraction medium.
Other known varying conditions for starting material extraction include varying extraction times and temperatures to facilitate extraction of soluble carbohydrates and proteinaceous materials. The present invention for removing extraneous matter is applicable to solubilization process flours or flakes of carbohydrate and proteinaceous fractions, preferably "waste" flake fractions from which the bulk of soluble carbohydrates and proteins has been removed. can be applied to Therefore, the invention is not intended to be limited by this particular material applied, but simply by retaining the waste flake fraction and then applying the method of the invention to remove extraneous material. , thereby improving the quality of the waste flake fraction for further processing is advantageous in normal operations for producing soybean isolate. Therefore, although it is contemplated that the method of the present invention may be used to remove debris or extraneous matter from other plant protein materials, the present invention is specifically described. The present invention will be described with particular reference to the removal of extraneous material from waste flake residues or aqueous alkaline extracts in order to achieve the desired results. Waste flakes or aqueous alkaline extraction residues from conventional isolate processes, even if not already in slurry form, can be turned into an aqueous slurry with a solids concentration suitable for centrifugation and from which extraneous materials can be effectively removed. . Typically, the slurry has or is adjusted to have a solids content of 2-10% by weight, preferably 3-5% by weight. Although it is not critical to the practice of the present invention to grind the waste flake residue or plant protein material before or after forming the slurry, it is preferred to grind the waste flake residue or plant protein material to effectively remove extraneous matter. Preferably, the waste flake residue is ground prior to the formation of the waste flake residue. As an example, and if the dry material is to be ground prior to slurry formation, typical (but not limiting) size ranges include retention of no more than 10% of the dry ground material on a 60 mesh sieve (.25 mm) and a 200 mesh sieve (.25 mm). 074mm) of crushed material at 50
% or more is on hold. Solids bowl or basket centrifuges (vertical or horizontal) that are commonly used to form a slurry of waste flake residue material followed by dewatering or increasing the solids content of a slurry of this type of material.
subject to continuous centrifugation in any type of Therefore, the invention is not intended to be limited to any particular type of centrifuge or apparatus for this purpose. It is clear that any bowl or basket centrifuge or similar equipment suitable for batch or continuous operation may be used in the present invention. However, the essential feature of the invention concerns the regulation of the centrifugation conditions, so that extraneous materials are removed in a separate fraction from the plant protein fraction to be retained in slurry form. It was therefore determined that adjustment of centrifugation conditions to separate irrelevant materials included the use of centrifugal forces and times of 10,000 to 50,000 G-seconds. The term "G-seconds" shall refer to the exposure of any given particle to a centrifugal force equal to gravity for one second. Preferably, the centrifugal force and time are about
30,000 G-seconds or less, most preferably about 20,000
and 10,000 G-seconds. The use of centrifugation conditions in the range of 10,000 to 50,000 G-seconds ensures that the desired plant protein material is essentially retained in slurry form and that extraneous matter or debris is concentrated in the centrifuge. It was determined that above these centrifugation conditions, the plant protein material would be concentrated together with extraneous material. This level of force and time is, of course, essentially the same as previously used for dehydrating plant proteinaceous materials. The inventors have discovered that conditions commonly used for dehydration of proteinaceous materials also retain debris or extraneous matter, thereby limiting the usefulness of the waste flake residue fraction for further processing or use as a food ingredient. has been established. centrifugation
By adjusting from 10,000 to 50,000 G-sec, extraneous matter is substantially removed as a separate fraction, at least to this extent, which significantly improves the residual color of the waste flake residue. After centrifuging the slurry of waste flake residue to remove extraneous matter, the slurry containing the plant protein material is collected and preferably subjected to a conventional dehydration process so that the plant protein material can be easily dried to remove the material. to thicken the solids content of. The number of debris removal sequences that may be used is not intended to limit the invention. This is because it is clear that the plant protein material can in fact be subjected to more than one process, including two or more steps of removing extraneous material as well as dehydrating the cleaning waste flake residue. The product waste flake residue that has been cleaned by removal of extraneous material has been found to have a significantly improved color over the conventionally processed waste flake residue product. In this regard, conventional waste flake products obtained from unpurified starting materials typically contain extraneous materials that appear as "black spots" in the product, and therefore these products are Significant amounts of unextracted residual protein (10− on a dry basis)
45%), its usefulness as a food ingredient will be limited. Accordingly, the present invention significantly improves the color of waste flake residue, thus increasing its functionality as a food ingredient. Such functionality includes use in various types of food ingredients, including breads, baked goods, or various food products intended to have increased fiber or protein content. Particular applications of the products of the invention include as fillers in low-calorie, high-protein diets, as base agents or thickeners in tomato products, fruit drinks, salad sauces, etc., and in ground meat systems. Uses as moisture or fat binders are included. Next, specific but not limiting aspects of the present invention will be described with reference to Examples. Example 1 1600 lbs of undehydrated, ground "waste flake" residue having a solids content of 7.5% obtained from the production of soy protein isolate is divided into separate portions to illustrate the process of the present invention. did. An 800 lbs portion of the above fraction (referred to as "A") was centrifuged at 75529 G-seconds to concentrate the slurry. The concentrated slurry was adjusted to PH6.5 and solids content 5.1% by weight, and US Standard #20
Passed through a grinder using mesh sieves. The milled slurry was then heated in a jet steamer to sterilize the product. The slurry was fed to a spray dryer at 3000 psi operating at an exhaust temperature of 220° and dried. 800lbs of the above fraction (referred to as "B")
(solids content 7.5% by weight) was centrifuged at 14442 G-sec to remove extraneous material from the slurry.
After removal of extraneous materials, the slurry was centrifuged at approximately 75,000 G-seconds to concentrate the cleaned material. slurry
Adjusted to PH6.5, solids content 4-4.5%, US standard #20
Passed through a grinder with mesh sieves. The milled slurry was heated in a jet steamer to sterilize the product and then fed to a spray dryer operated at an exhaust temperature of 220°C and dried at 3000psi. A sample of the spray dried product from portions “A” and “B” is examined and visually portion “B” is whiter in color than portion “A”;
It was observed that extraneous material had been removed.
It was also observed that portion "A" was characterized by a significant number of "black spots" representing extraneous matter in the spray dried product. Color measurement of the above samples was performed by slurrying each sample with water to a solids content of 10% and measuring the color of each sample using a Hunter Lab Colorimeter.
This was done by measuring with a Colorimeter).
The chromaticity values were as follows.

[Table] By comparing readings on the "L" scale,
It can be seen that the sample from portion "B", from which extraneous material has been removed, has improved brightness over the sample from portion "A", which is only processed in the conventional manner. Although the invention has been described in terms of these specific embodiments, it is understood that numerous changes can be made without departing from the spirit of the invention and are intended to be encompassed within the scope of the invention. It's obvious.

Claims (1)

Claims: 1. (a) forming a slurry of plant protein solid material having a solids content of 2 to 10% by weight and containing solid material unrelated to the plant protein material; (b) forming said slurry; (c) separating said slurry by continuous centrifugation at 10,000-50,000 G-sec into a fraction consisting of a slurry of said plant protein solid material and a fraction containing said unrelated solid material in concentrated form; (c) then said plant protein solids; A method for removing extraneous solid materials from a plant protein material, comprising: taking a fraction consisting of a slurry of the material. 2. The method according to claim 1, wherein the slurry is centrifuged at 30,000 G-seconds or less. 3. The method of claim 2, wherein the slurry is centrifuged at between 20,000 and 10,000 G-seconds. 4. The method of claim 1, wherein the slurry has a solids content of 3 to 5% by weight. 5. The method according to claim 1, wherein the plant protein material is a soybean material. 6. The method of claim 5, wherein the soy material is waste flake fraction from soy isolate production.