KR20080090777A - Process for manufacturing tagatose using by-product produced from processes for isolated soy protein - Google Patents

Abstract

A preparation method of tagatose using by-products of isolated soybean protein is provided to obtain galactose from the soybean pulp and soybean produced in the congelation process of islolated soybean protein. A preparation method of galactose using by-products of isolated soybean protein comprises the steps of: adding a strong acid to by-products of islated soybean protein, and hydrolyzing them; netralizing the hydrolzed by-products; and separating out galactose by using chromatography. The strong acid is sulphuric acid, nitric acid, or hydrochloric acid. Tagatose is obtained by isomerizing the galactose.

Description

Production of Tagatose Using By-Products of Soybean Isolate Protein {PROCESS FOR MANUFACTURING TAGATOSE USING BY-PRODUCT PRODUCED FROM PROCESSES FOR ISOLATED SOY PROTEIN}

1 is a schematic process chart of soybean separation protein.

Figure 2 is a graph showing the content of galactose extraction over time of the sulfuric acid hydrolysis result of soy whey.

The present invention relates to a method for producing tagatose using a by-product of soybean isolate, and more particularly, galactose contained in a high proportion in soybean isolate and soy whey obtained as a byproduct in the coagulation separation process of soy protein. The present invention relates to a method of preparing tagatose using the same and separating the same.

In general, soybean separation protein is subjected to the process as shown in Figure 1 using skim soybean meal as a raw material. An extract obtained by extracting skim soybean meal with alkaline water is first obtained, and acid is added to the obtained alkaline water extract to add acid. The protein coagulation precipitate generated at this time is recovered secondly, washed with washing water, and finally high soybean separation protein is obtained. Therefore, two by-products of the soy isolate are produced, insoluble precipitates generated in the alkaline water extraction process and soy whey obtained after sedimentation in the protein coagulation precipitation process. It is usually processed through a process.

Tagatose has a natural sweetness that is almost indistinguishable from sugar, and its physical properties are similar to sugar. However, ingested tagatose is not absorbed well in the small intestine and does not affect blood sugar levels, and calorie is a low-calorie sweetener, about 30% of the sugar. Tagatose also has a prebiotic effect that promotes the growth of beneficial lactic acid bacteria by fermentation by intestinal microorganisms.

However, since tagatose is not commonly present in nature but is a rare sugar contained in dairy products or some plants, a technique for mass production from inexpensive raw materials must be developed to be used as a low-calorie functional sweetener.

 U.S. Patent No. 5002612 and 5078796 disclose D-taga using lactase to hydrolyze lactose or lactose-containing substances into a mixture of galactose and glucose, optionally remove glucose, and then chemically isomerize galactose to tagatose. Provided is a method for preparing toss.

U. S. Patent No. 6057135 also discloses the steps of hydrolyzing cheese whey or milk to obtain galactose and glucose, isomerizing the obtained galactose with L-arabinose isomerase, and the product and non-converting compound. Chromatography is separated to provide a method for producing tagatose comprising the step of recycling the non-converted compound to the process.

The key raw materials used to produce tagatose so far are dairy by-products such as lactose or lactose-containing substances. In the bioconversion process using such lactose or lactose-containing material as a starting material, the production method of tagatose should be basically carried out in a two-step reaction (lactose → galactose → tagatose).

However, the price of lactose or lactose-containing products (whey, whey permeate) in the world market depends on a variety of factors that cannot be quantified, such as crude oil production, milk powder demand, and changes in lactose consumption in third countries. As a result, prices in the market are not constant and have a unique price pattern that repeats rising and falling. Raw material price fluctuations in these markets make it difficult to supply stable tagatose raw materials. In particular, the recent increase in consumption in the third country market is breaking even the original price pattern to date, and even causing the ideal price increase of lactose-containing substances. In addition, galactose, which is a key intermediate in production using the enzyme process of tagatose, is currently supplied through the decomposition of lactose.

Galactose, although relatively small, is a monosaccharide component widely found in nature, and is present in many of the basic building blocks of carbohydrates in organisms. Typical carbohydrates containing galactose are listed in Table 1 below.

Carbohydrate Name Party members Galactose Content (%) Sugar content ratio of constituent units Lactose 2-sugar 50 D-Glu: D-Gal = 1: 1 Raffinose 3 tan sugar 33.3 D-Glu: D-Fru: D-Gal = 1: 1: 1 Baby Polysaccharides 50 D-Gal: 3,6 anhydro-L-Gal = 1: 1 Guar gum (galactomanan) Polysaccharides 33.3 D-Gal: D-Mannose = 1: 2 Arabinogalactan Polysaccharides 67 L-Ara: D-Gal = 1: 2

However, it is uneconomical to use these galactose-containing carbohydrate sources directly from nature. Galactose-containing carbohydrates, which are not used or not suitable for use, are by-products of existing production processes that currently use large quantities of plants containing various kinds of proteins, fats and sugars as raw materials. Large amounts of these have been reported.

As mentioned above, significant value added can be obtained when galactose is obtained from materials obtained as by-products during the processing and threshing of plants or grains present in nature.

Therefore, based on this fact, the present inventors collected the materials that are expected to contain a large amount of galactose among wood and process by-products that can be supplied at low cost in the natural world, and measured the galactose content. It was found to have galactose content exceeding 40% compared to other materials. From this it was discovered that galactose can be obtained through practically industrializable levels of hydrolysis conditions, and have come to complete the present invention.

Accordingly, a main object of the present invention is to provide a method for obtaining galactose through hydrolysis of soybean isolates and soy whey obtained as by-products of soybean isolates for use as raw materials for producing tagatose. .

Still another object of the present invention is to provide a method for producing tagatose using galactose obtained from the soybean isolate protein or soy whey.

In order to achieve the above object, the present invention in the conventional production method for producing tagatose through an enzymatic engineering method, by using galactose obtained from galactose from the existing lactose or lactose-containing material Unlike the existing inventors who want to produce a, it provides a method for producing tagatose by recovering galactose in high yields from soybean isolates and soy whey, which are by-products of soybean isolates.

The present invention will be described in detail as follows.

The by-products of the soybean isolate protein of the present invention include soybean isolate protein and soy whey obtained as by-products in the production of soybean isolate protein.

Soybean isolate protein of the present invention refers to the (pulp) remaining after the alkaline extraction of soybean meal (pulp), soybean whey means excess soybean whey (soybean whey) that is discarded after the protein mass formation process.

The industrially widely used soybean separation protein production process is a representative environmental pollution type process using a large amount of water, and the amount of waste water is large. Soybean protein separation meal that can be obtained cheaply as a by-product when producing soybean separation protein is low. It is being consumed locally for feed, and soy whey is mostly being treated by wastewater treatment.

The present invention provides a method for obtaining galactose through hydrolysis of soybean isolates and soy whey obtained as by-products of soybean isolates for use as raw materials for tagatose production.

The method for obtaining galactose comprises the steps of hydrolysis by adding acid to soybean isolate protein or soy whey; Neutralizing it; And separating galactose using chromatography.

The acid used in the present invention includes a strong acid such as sulfuric acid, nitric acid and hydrochloric acid as a substance used for hydrolysis of carbohydrate components.

In the acid hydrolysis of the present invention, when soy whey is used as a galactose source, 500-1,500 g of 0.1-3.0% sulfuric acid solution is added to 100 g of soy whey on a dry weight basis, and the ratio of liquid and solid is 1: 5-1. After the reaction mixture was made at: 15, the reaction temperature was stirred at 10 to 50 rpm at a reaction temperature of 110 to 200 ° C and a reaction pressure of 1.0 to 10.0 kgf / cm ² for 0.5 to 5 hours.

Thereafter, as a neutralizing step, calcium salt is added to remove sulfuric acid added to the reaction solution obtained by the hydrolysis. After adjusting to pH 4.0-6.0, it stirred for 30 to 120 minutes, aggregated into calcium sulfate which is a form of an inorganic salt, and it filtered and removes calcium sulfate. The calcium salt used preferably includes calcium hydroxide, calcium carbonate and the like.

The galactose of the present invention is obtained by the method described above and separated using chromatography to use as raw material for tagatose production.

The present invention also provides a method for producing tagatose using galactose obtained from the soybean isolate protein or soy whey.

As the arabinose isomerase used in the present invention, the enzyme used in the conventional holding technique was used as it is.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, these examples are for illustrative purposes only and the scope of the present invention is not limited to these examples.

 EXAMPLE

In the embodiment of the present invention, in order to secure a low-cost and stable supply of galactose source, the content of galactose sugar source in the by-product obtained from the production process of carbohydrate or protein component produced in large quantities in the food industry was used as an index thereof. In addition, by-products of soybean isolates containing abundantly selected galactose were hydrolyzed, and galactose in the whole sugar component was obtained in high yield up to 74.6% under relatively mild conditions.

Example 1 Ingredient Analysis by Raw Material for Selection of Galactose Source

For the selection of galactose source, lactic acid, soybean isolate, soybean whey, soybean hull, and octave were selected as by-products that are considered to have a relatively high content of galactose. In order to analyze the content component of the galactose sugar source of the selected raw materials, the following test method was performed and then analyzed.

First, 5-10 g of each selected raw material was taken, and then dried at 40-60 ° C. for 24 to 48 hours. Approximately 0.3 g of each dried raw material was weighed in a glass tube and placed in a glass tube, followed by addition of 3 ml of 72% H ₂ SO ₄ (specific gravity 1.6389). After the sample was immersed in 72% H ₂ SO ₄ solution, a glass rod was placed in each glass tube. Thereafter, a glass tube was placed in a shaking water bath set at 30 ° C. and acid hydrolyzed for 2 hours. During the hydrolysis, the glass rods were stirred at 30 minute intervals with glass rods.

An acid hydrolyzed sample was added to a 250 ml bottle for 2 hours, and 84 ml of distilled water was added thereto. Distilled water was added while washing the glass tube divided into 25 ml + 25 ml + 25 ml + 9 ml. The bottle containing the sample was subjected to secondary acid hydrolysis while sterilizing at 121 ° C. for 1 hour. The internal temperature of the autoclave was taken out at 50 ° C. and left to cool to room temperature. 10 ml of the supernatant was taken from a fully cooled bottle, placed in a conical tube, and neutralized by addition of CaCO ₃ . At this time, it was confirmed to be neutral using a pH paper (pH paper or test paper).

The neutralized solution was left to cool at room temperature, and then, 1 ml of the supernatant was collected, placed in an eppendorf tube, and neutralized again by adding CaCO ₃ . Eppendorf tubes were placed in a centrifuge and centrifuged at 10,000 rpm for 20 minutes. Only the supernatant in the Eppendorf tube was collected using a syringe, filtered and placed in a vial for HPLC, and the solution was analyzed by HPLC. As a result, the obtained sugar component analysis results were as in Table 2.

Raw material name Sugar Ingredients (%) Galactose glucose Arabinos larch 1.6 7 7 Soybean isolate protein 11.7 12 16.1 Soy Whey 21.8 12.4 15.2 Soybean Scalp One 11.7 11.7 Octopus 0 33.2 14

Example 2 Results of Hydrolysis Using Soy Whey

The soy whey was confirmed to have the highest galactose content in Example 1, and the following experiment was carried out to measure the yield of galactose when the hydrolysis process was applied at a substantially applicable level.

Soy whey was used in hydrolysis experiments by adding 1.6 L of distilled water to 80 g of dry weight. Hydrolysis was performed at 150 ° C. after addition of 1% sulfuric acid, and the content of galactose was finally determined using HPLC. As a result, it was found that when treated with 1% sulfuric acid at 150 ° C, galactose showed a hydrolysis yield of 74.57%, the highest yield in 10 minutes, which is 16.2% by weight of the total soy whey. Each detection value is shown in Table 3, and the galactose extraction content according to the reaction time to see the pattern of hydrolysis is shown in FIG.

Reaction time Hydrolysis Yield (%) g-gal / 100 g soy whey 0 41.76 9.10368 10 74.57 16.25626 20 74.06 16.14508 30 72.3 15.7614 40 72.3 15.7614 60 70.9 15.4562 80 67.08 14.62344 100 62.82 13.69476 120 59.89 13.05602 150 24 5.232

As described in detail above, through the hydrolysis of the by-products of the soybean separation protein, it is possible to obtain a high yield of galactose solution, thereby securing a raw material of tagatose that can be supplied at low cost and stable.

Claims (4)

Hydrolyzing by adding a strong acid to the by-product of the soybean separation protein; Neutralizing it; And Method for producing galactose, characterized in that it comprises the step of separating the galactose using chromatography. The method of claim 1, The production method of galactose, characterized in that the by-product of the soybean separation protein comprises soybean separation protein foil or soy whey. The method of claim 1, Process for producing galactose, characterized in that the strong acid is sulfuric acid, nitric acid or hydrochloric acid. Method for producing tagatose, comprising the step of isomerizing galactose according to the method of claim 1 to obtain tagatose.

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