KR820001416B1 - Process for producing multi-sugar syrups plus chystalline dertrose form starch - Google Patents

Abstract

Multisugar syrup and cryst. dextrose were prepd. by liquefaction (α- amylase) and saccharification (β- amylase, glucoamylase) of corn starch to give a hydrolyzate contg. 70- 90 % dextrose and 5-30 % of at least 1 other sugar, followed by crystn. to form dextrose crystals; the crystals were sepd. by centrifugation. Some of the dextrose in the syrup remaining was isomerized (glucose isomerase) to levulose to give a very sweet noncrystallizable syrup. After filtering and refining by ion exchange the product could be used in food products.

Description

Method for preparing crystalline glucose and various low sugar molasses from starch

The present invention relates to a method of recovering expensive starch molasses by treating starch with crystalline glucose and by-products. A common byproduct of glucose crystallization is low cost hydrorolls.

Conventional methods for preparing glucose monohydrate from starch are now well known. Starch is first diluted with acids or enzymes (generally bacterial alpha-amylase) and then glycosylated using gluco-amylase enzymes. The saccharification proceeds until a maximum amount of glucose is formed (about 92-98% on a dry basis, depending on the dilution method used), followed by crystallization by filtration and purification of the hydrolyzate.

The crystallization work is carried out as follows. First, the hydrolyzate (by temperature and solids content control) is brought to the supersaturation state of glucose, seed crystals are added to start crystallization, and then the material is slowly cooled to ensure that the optimum amount of crystals is the optimal size for efficient and economic recovery. Let grow. As a rule 50-60% of the glucose crystallizes, the crystals are centrifuged from the mother liquor, leaving behind a first green liquid phase.

The first green liquid phase contains about 75% dry matter, of which about 82% is glucose. (The rest are high sugars). Since the first green liquid phase has no economic value, it is recycled to the first crystallization step or sent to another crystallization step to recover the crystals further. The remaining liquid after separating the crystals from the first green liquid phase is called hydroroll or the second green liquid phase and is a solution containing 52-60% of solid matter. This solution contains about 53-75% of glucose, maltose, isomaltose and higher sugars. It is a low cost by-product and used for animal feed and various industrial uses.

When starch is treated by the method of the present invention, instead of obtaining a single main product (glucose) and a low cost by-product hydroroll, two main products are obtained: (1) glucose and (2) expensive molasses. This molasses contains glucose and at least one lower saccharide (mono- or di-saccharides), which may be used as it is, mixed with other lower saccharides or molasses, or further processed to form molasses with different sugar contents. Can be generated. No matter how this by-product is finally used, it is a far more useful and valuable by-product than conventional hydrorolls.

The present invention relates to a method of treating starch to obtain molasses containing two main products (1) crystalline glucose and (2) at least two lower saccharides. This method consists of the following steps. (a) treating the starch to obtain a hydrolyzate containing 70-90% glucose and at least one other lower saccharide of 30-5%, (b) crystallizing the hydrolyzate to form glucose crystals, ( c) recovering liquid molasses of crystalline glucose and various lower saccharides by applying a solid-liquid separation method to the mother liquor.

In the process of the present invention, the starch is first diluted with acids or enzymes according to conventional methods and treated to contain 70-90% (preferably 75%) of glucose and at least one mono- or di-saccharide. To produce a hydrolyzate. Glucose crystallization of this hydrolyzate in a conventional manner results in significant crystallization of about (45-55%) of glucose and recovery of the glucose crystals from the mother liquor by conventional solid-liquid separation, ie centrifugation or filtration. As a result, the remaining liquid acid is not a conventional first green liquid phase but contains expensive molasses of various kinds of lower saccharides, and this liquid phase can be used as described above or further processed. This polysaccharide of molasses contains at least about 53% of glucose and thus crystallizes if maintained at a solid concentration of at least 65% at room temperature for a significant time. Therefore, crystallization can be avoided by keeping molasses hot, but it is more desirable to mix it with other sweeteners or add chemical and / or enzymatic treatment to lower the glucose content so that it can be amorphous even at high solids concentrations and at ambient temperatures. Hydrolysates containing a high glucose content and containing a variety of lower saccharides can be prepared in a variety of ways, all of which include the step of glycosylating with glucoamylase to obtain glucose at the desired level. For example, diluted starch can be glycosylated with glucoamylase and at least one other enzyme, which can be applied simultaneously or in any order to produce hydrolysates containing 70-90% glucose and other lower saccharides such as maltose or fructose. Done. It is also possible to form at least one ketosaccharide with glucose by applying an alkaline isomerization method at any stage of the process, for example, first by glycosylation with glycosylation to form maltose, isomerization with alkali to form maltose isomers, and then hydrolyzate Treatment with glucoamylase can produce the required amount of glucose.

The composition (sugar content) of the second main product produced by the method of the present invention can be determined in advance by the composition of the first hydrolyzate, and depends on various conditions used. The products that can be produced vary widely. The methods per se are well known for producing hydrolysates of various lower saccharides from starch, such as by treatment with multiple enzymes or by alkaline isomerization methods. In addition, various methods are known for producing glucose-fructose molasses by treating a hydrolyzate having a high glucose content with an isozyme isomer.

In general, the conventional methods aimed at the production of a variety of lower saccharide molasses themselves, in particular for the production of molasses that does not crystallize during storage and / or transportation. Therefore, the products of the conventional process had a relatively low glucose content to avoid crystallization. In all conventional polysaccharides, polyhydrates of polysaccharides were recovered as final products.

The process of the present invention uses a completely different method. That is, the hydrolyzate of the various lower saccharides is in fact an intermediate product and is prepared from the beginning to contain at least 70% glucose. Glucose crystals are then recovered and the second main product, the low polysaccharide molasses, is left. The reason why the hydrolyzate should contain at least 70% glucose is that crystallization of glucose cannot occur from hydrolyzate containing less than this amount. Crystallization is possible even from hydrolysates of 70% glucose. At this glucose level, the crystallization process takes a very long time. For the most practical and economical work it is desirable to use hydrolysates containing at least 75% glucose. The following examples show specific examples of the present invention, but the scope of the present invention is not limited to these examples, but merely illustrates various possible specific methods and various products that can be obtained from these methods. In the following examples and claims, all percentages are by dry weight unless otherwise indicated. When the enzyme dose is expressed in active units (AU), it is based on 1 kg of dry substrate. DP indicates the degree of polymerization. At the end of the example, a method for measuring the active units of the various enzymes used is presented.

Example 1

Preparation of Glucose-Maltose Multi-Lower Sugars Product (Optionally Prepare Glucose-Fructose-Maltose Product by Isomerization Method).

1. Liquefaction stage

CaCl ₂ was added to an aqueous slurry of 31.5% corn starch to provide 150 ppm of Ca ions. The pH was adjusted to 6.5 and 1600 active units of α-amylase were added.

The slurry was heated at 85 ° C. for 30 minutes and then raised to 135 ° C. for 5 minutes. The temperature was lowered back to 85 ° C. and 1,600 active units of alpha-amylase were added, and the product was held at this temperature for 60 minutes. PH during liquefaction was 6.5. The liquefied starch had a D.E of 12.3 and a saccharide composition as follows.

2.Saccharification

Liquefied starch slurry (containing about 34% of dry matter) to 5 pH5. 57 ° C. and 0.05% β-amylase and 80 AU of glocoamiral agent were added. The product obtained after saccharification for 30 hours under this condition had the following composition.

The pH was adjusted to 4.2 and 80 AU of glucoamylase was added. After further liquefaction for 20 hours, the resulting hydrolyzate had the following composition.

The hydrolyzate was then purified by filtration.

3. Crystallization

The hydrolyzate was concentrated to 73% dry matter and transferred to a crystallite at 55 ° C. 8% glucose mono-hydrate seed crystals were added to the liquid material, and the mixture was stirred slowly and cooled to 20 ° C. over 70 hours. About 52% of glucose crystallized and these crystals were centrifuged from the mother liquor. The remaining liquid phase was a solution of 53% solids and had the following composition.

The very sweet product was further processed to produce expensive, low-grade saccharide molasses in the following manner.

4.Isomerization of liquid product

The product was adjusted to a temperature of 60% dry matter, pH6.5 and 60 ° C., and 1250AU of glucose enzyme isomer was added. Magnesium was also added at 200 ppm. The isomerization reaction was carried out for 38 hours, and then the product was demetallized by ion exchange to remove magnesium. The final product had the following composition.

The product was very sweet amorphous molasses and could be beneficially used in various foods such as jams, ice cream and confectionery.

Example 2

Preparation of Glucose-Fructose-Malt Sugar Multiple Low Sugar Products

1. Liquefaction

The liquefaction method is the same as in Example 1.

2.Saccharification

The product was adjusted to pH 5 and 50 ° C. and 100 AU β-amylase and 1600 AU pullulase were added.

After saccharification for 24 hours, the resulting product had the following composition.

The pH was adjusted to 4.2 and the temperature raised to 60 ° C. followed by the addition of 180AU of glucoamylase. The saccharification was then continued for 40 hours to give the product of the next composition.

The pH was adjusted to 6.5 and the product was concentrated to 60% solids, then 600 AU of Glocose Enzyme Isomer was added. Isomerization reaction was performed at 60 degreeC for 12 hours, and the final hydrolyzate of the following composition was obtained.

The hydrolyzate was filtered off and purified by ion exchange.

3. Crystallization

The hydrolyzate was evaporated to 75% dry matter and crystallized as in Example 1. About 48% of glucose was crystallized and the crystals were recovered as in Example 1. The remaining liquid contained 54% of dry matter and had the following composition.

The product was very sweet and could be mixed with conventional starch molasses to produce amorphous molasses.

In this example the product was mixed with maltodextrin of 12 DE (prepared in the same manner as in the liquefaction process of this example and example 1) and the ratio was about 65% molasses and 35% maltodextrin combined The product of the composition was obtained.

Concentrating the above product to 85% solids to obtain amorphous molasses. The mixed product was sweet and high in viscosity and exhibited excellent udon when used in the manufacture of sweets, nougat, marshmallows, jams and ice cream.

Example 3

Preparation of Fructose-Glucose Multi-Lower Sugars Product

1. Preparation of hydrolyzate

Glucose was prepared from the starch by a conventional process. In other words, it was diluted with α-amylase and glycosylated with glufoamylase to obtain a product having the following composition.

The hydrolyzate was subjected to an isomerization reaction of 900AU of glucose enzyme isomer for 12 hours under similar conditions as in Examples 1 and 2 to obtain a product of the following composition.

The product was filtered and purified as in the above example.

2. Crystallization

The hydrolyzate was concentrated to 7.5% dry matter and crystallized as in the above example. About 55% glucose was crystallized and this crystal was removed as in the above example.

The remaining liquid had the following composition.

The resulting product was mixed with conventional molasses containing 2% glucose, 76% maltose and 22% higher sugars, with a ratio of 25% molasses and 7.5% fructose-glucose product to Got.

The final product was very sweet and amorphous molasses.

Example 4

Preparation of Fructose-Glucose-Maltose-Maltose Isomer Multi-Lower Sugars Product

1. Preparation of hydrolyzate

Molasses with high maltose content was prepared as in Example 2. This molasses contained 3.7% glucose, 73% maltose and 24.3% high sugars. Part of the maltose was made into the maltose isomer by the alkaline isomerization method. NaOH was added to the concentrated hydrolyzate (concentration of 60% solids) to pH 0.5, followed by 2% sodium aluminate by weight of dry molasses to give the product at 65-70 ° C. for 3 hours. Maintained. The product purified by ion exchange had the following composition.

The above product was adjusted to pH4.2 and 160AU of glucoamylase was added, and then the product was glycosylated at 60 ° C. for 60 hours to obtain a product having the following composition.

The hydrolyzate was filtered and purified as in the previous example.

2. Crystallization

The hydrolyzate was concentrated to 74% dry matter and crystallized as in the previous example. About 48% of glucose crystallized and this crystal was removed as in the previous example. The remaining liquid phase had the following composition.

This product was very sweet and useful as a sweetener in various food products. This product could be amorphous at high solids concentrations by mixing with maltodextrin, maltose-containing molasses and the like. The product was further treated with a glucose enzyme isomer to isomerize a portion of the glucose present (up to 50%) with fructose to obtain a sweeter amorphous molasses.

[Determination of Active Units (AU)]

The following is a method for determining the active units of various enzymes used in the above examples. The activity of glucoamylase expressed in active units is D.E. Using 10-20 starch hydrolysates as substrate, a total of 2 hours tablets is the number of g of lower saccharides that 1 g of enzyme decreases over 1 hour at 60 ° C. and pH 4.3 over time.

β-amylase activity is determined as follows. Add exactly 5% solution of starch hydrolysate and 50 ml of 15-20 glucose equivalents, 5 ml of 0.5 molecular weight acetic acid / sodium acetate buffer adjusted to pH 4-6. The mixture is equilibrated at 50 ° C. for 15 minutes and then a weighted enzyme sample is added. Also make a comparative sample in which the enzyme solution is replaced with distilled water. After mixing, keep the experiment at 50 ° C for 55-57 minutes and add 3 drops of fennelphthal lane indicator. Exactly 60 minutes later, the flask was removed from the heating bath and 1% sodium hydroxide solution was added to immediately neutralize it to a light pink color, then add 0.5 ml more. The solution is then cooled to room temperature and diluted to exactly 100 ml.

Reduced lower saccharides of the enzyme sample are determined by standard methods widely used in industry. Activity is calculated from the following formula.

Where R.S. = Total reduced lower saccharide, pullulanase activity in the enzyme sample taken for analysis is determined as follows. 1 g of pullulan is boiled in 70 ml of distilled water for 5 minutes, then cooled, 10 ml of 1 molar acetic acid buffer (pH 5.0) is added and the whole is diluted to 100 ml. This is filtered last. The 1m pullulan solution was maintained at 50 ° C. for 5 minutes, and then 1 ml of enzyme solution was added to allow the reaction to proceed for exactly 10 minutes. The reaction is stopped by adding 2 ml of DNS reagent. DNS reagent is prepared by adding 1 g of 3.5-dinithsalicylic acid to 16 ml of 10% sodium hydroxide solution, and diluting it to 100 ml by adding 30 g of Rochelle salt.

A comparative sample is made by adding 2 ml of DNS reagent to the substrate prior to the enzyme. The two specimens are placed in a boiling water bath for exactly 5 minutes, then quenched and mixed by adding distilled water.

Using a 2 cm cavity having a wavelength of 540 μm, the optical density of the experimental solution is compared with respect to the comparative sample. The 0.4 pullulanase active unit gives an optical density of 0.325. Therefore, various dilution experiments are carried out, and the optical density of the enzyme concentration is drawn. A concentration giving an optical density of normal 0.325 includes 0.4 pullulanase active units. Therefore, the activity of the enzyme sample is calculated by the formula

Active (polyolanase units) =

The activity of the glucose enzyme isomers expressed in active units is the number of micromoles generated in 1 minute at 60 ° C. and pH7.5 by 1 g of enzyme over a 30 minute period of calm using a 10% D.S glucose solution.

Claims (1)

Treating the starch to produce a hydrolyzate comprising 70-90% glucose and at least 30-5% at least another lower grade sugar, crystallizing the hydrolyzate to form glucose crystals, and the mother liquor thus produced Recovering crystalline glucose and liquid low polysaccharide molasses by applying a solid-liquid separation process to the same, and preparing molasses containing two main products, crystalline glucose and at least two low sugars, from starch. .