JPH0791322B2 - Partially debranched starch produced by enzymatic methods - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field The present invention relates to a composition of matter consisting of partially debranched starch produced by enzymatic debranching and enzymatically debranched starches. The present invention relates to a manufacturing method.

PRIOR ART AND PROBLEMS TO BE SOLVED BY THE INVENTION Starch is a polysaccharide which is typically composed of a mixture of about 20-25% amylose and about 75-80% amylopectin derived from compressed granular starch. Amylose is a linear polymer of glucopyranosyl units linked by α-1,4-D-glucosidic bonds. Amylopectin is a giant branching polymer of amylose chains linked by α-1,6-D-glucosidic bonds in a tree-like structure. Due to the variety of plants from which starch is obtained,
Amylose originally has 250-12,500 D-anhydroglucose units and amylopectin has 40,00-3,15.
It has 0.000 Lopectin D-anhydroglucose units.

Enzymes and mixtures of enzymes that saccharify and debran starch have been used in starch conversion processes for the industrial production of low molecular weight oligosaccharides such as dextrose (glucose) and sucrose. Starch conversion is the conversion of starch to low molecular weight components by treatment with acids, oxidants, heat, alkali or alpha-amylase enzymes. Enzymatic conversions of starch specifically include preferential hydrolysis of the α-1,4-D-glucoside bond, and, to a limited extent, hydrolysis of the α-1,4-D-glucoside bond. Can be mentioned.

In the enzymatic conversion of starch to thin-boiling (low viscosity) starch, hydrolysis of branched fragments can be incomplete. However, for sucrose production, the conversion of starch to sucrose is desirable and a branched alpha-restricted text that remains intact after enzymatic hydrolysis of the α-1,4-D-glucoside linkage using debranching enzymes. It degrades the phosphorus amylase, a branched starch fragment that is resistant to further hydrolysis by alpha-amylase. Glucoamylarase (gluc), an enzyme that liquefies and saccharifies starch
oamylase) is used for this purpose. Glycoamylase immediately hydrolyzes α-1,4-D-glucoside bonds, and hydrolyzes α-1,6-D-glucoside bonds. Pullulanase or isoamylase that hydrolyzes α-1,6-D-glucoside bonds to release short-chain amylose
Such debranching enzymes have been proposed for use in combination with glucoamylase and alpha-amylase to improve the efficiency of production of high dextrose syrups. These syrups are the starting materials in the production of crystalline dextrose and high fructose corn syrup. Maize, Recent Progress in Che
mistry and Technology, pp. 157-179, Academic Press,
Inc. (1982); and Slominska, L, et al., Starch / Stark.
e, 11: 386-390 (1985).

In addition, debranching enzymes (enzymes that release short-chain amylose from starch) are used in low-calorie alcoholic beverages that improve the fermentation of branched starch fragments;
For the production of maltose from starch in combination with amylase; Low DE to agglomerate proteins in aqueous emulsion
For maltodextrin (30-50 glucose units) production;
And its use for the enzymatic conversion of starch into soluble syrups with high quality disaccharides and trisaccharides. The application of these debranching enzymes leads to problems arising from branched starch or dextrin fragments associated with the starch conversion process. In each application, the debranching enzyme is utilized to completely convert starch into various low molecular weight fragments such as sucrose or maltodextrin. The thickening, adhesive and gelling properties of starch are lost.

The use of debranching enzymes to debran starch sufficiently by hydrolysis of substantially all α-1,6-D-glucoside bonds to obtain pure or amylopectin-free low molecular weight amylose is described by Sugimoto et al. U.S. Patent No. 3,730,840
U.S. Pat. No. 3,881,991 to Kurimoto et al. And U.S. Pat. No. 3,879,212 to Yoshida et al. The above patents do not teach converting starch to sucrose and other soluble fragments. The purpose of the above patent is to provide short chain amylose. It is believed that the presence of any residual amylopectin is opposed.

The background of enzyme-related starch technology is that the effective starch composition utilizes a debranching enzyme to partially debran the amylopectin component of starch, with short chain amylose, with or without substantial starch conversion, It does not propose that it can be produced by obtaining amylopectin and partially debranched amylopectin. No literature proposes the use of enzymatic methods to partially debran starch as a wholly or partially substituted form and produce various modified starches, or partially debranched of the invention. It does not suggest the functional properties of starch. This enzymatic method offers significant advantages over other methods, especially in food and cosmetic applications where there is a demand for "natural" products.

(Means for Solving the Problems) Accordingly, the present invention provides a starch having various properties which is partially enzymatically debranched and which untreated branched starch does not retain. The above properties are in addition to the expected rheological properties (ie, thickening and adhesion) with which starches were originally used. These properties include, but are not limited to, oily to creamy to waxy fatty composition in aqueous dispersions, stable haze formation, cold water insoluble film formation, high strength gel formation and Thermoreversible gel formation is mentioned. Thermoreversible starch gels are those that melt when heated and reform when cooled. Gels made from unmodified starch are not thermoreversible.

The present invention also provides alpha-1,6-D-, such as pullulanase, isoamylase or amylo-1,6-glucosidase.
It is intended to provide a method for enzymatically producing these starches using glucanohydrase.

Enzymatically debranched starch consists of up to 80% by weight of short-chain amylose and at least 20% by weight of partially debranched amylopectin, and in many applications produces adipose tissue to aqueous dispersions. Giving a thermoreversible gel, forming a strong gel, forming a film,
It can be used to form a stable haze and thicken, bond, stabilize and displace modified or otherwise modified starch.

Enzymatically debranched starch is a proportion of partially debranched amylopectin, short chain amylose and if adjusted for a particular application by controlling the degree of debranching and selecting a starch source. Consists of amylopectin. Starches from many sources, such as corn, containing long chain amylose retain their long chain amylose content following enzymatic treatment. Starches from any source can be utilized in the present invention. Depending on the end use and the starch selected, the starch may be debranched by treatment with alpha-1,6-D-glucanohydrase until 80% by weight of starch is debranched into short chain amylose. it can.

The enzymatic treatment utilized in the method of the present invention is alpha-1,6
It can be done on any pregelatinized starch containing -D-glucosidic linkages. In the production of partially debranched starch, the starch is selected from a suitable sauce and slurried in water. The mixture is then cooked to gelatinize the starch. If desired, starch may be used in granular form, but the enzymatic degradation of granular starch proceeds slowly. The temperature and pH of the mixture are optimally adjusted to the particular enzyme used and then the slurry is contacted with the enzyme.

The enzyme must be an endo-enzyme capable of hydrolyzing the alpha-1,6-D-glucoside linkages of the starch molecule and not hydrolyzing a significant degree of the alpha-1,4-D-glucoside linkages. The preferred enzyme pullulanase, by its action, is alpha-1,4-
Alpha-1, located near the chain of D-glucoside bonds,
It is a highly specific endo-enzyme capable of forming a reaction complex with only 6-D-glucoside bonds. Since this endo-enzyme is able to hydrolyze the 1,6-bonds of the starch molecule, but not the 1,4-bonds, the balance of such debranching operations is higher than the starting material. It is a complex mixture containing an invariant proportion of chain molecules and branched chain molecules. Thus, the composition and properties of partially debranched starch were inconsistent with those of transformed starch (ie, low boiling starches, oligosaccharides, sucrose and dextrins) and were well debranched. Of starch (ie, short-chain and long-chain amylose)
Does not match.

The enzyme is capable of digesting starch until about 80% by weight of starch is debranched to short chain amylose or the desired end point (ie, sufficient debranching to give the desired functional properties) is reached. Admit. This product contains at least 20
Contains wt% partially debranched starch. Originally, the degradation is carried out for a period of time up to 24 hours or more, depending on temperature, enzyme and substrate concentrations and other manufacturing variables. The enzymatic degradation is then stopped by heat, addition of chemicals or other methods known in the art for inactivating enzymes. The partially debranched starch composition can be spray dried, drum dried, or recovered in a form suitable for its intended use.

The starch that can be used in the production of the enzymatically degraded starch of the present invention can be derived from any source such as corn, potato, sweet potato, wheat, rice, sago, tapioca, waxy corn, sorghum and the like. Oxidation, alpha-amylose conversion, mild acid hydrolysis or heat dextrinizatio
Also included are conversion products derived from any of the above starches including the free flowing or low boiling starches produced by n). Derived starch such as ethers and esters and other modified starches can also be used.

The starch is preferably gelatinized starch (pre-cooked, cold water swellable starch), which is converted by mild acid hydrolysis, thermal dextrinization or one of several methods known in the art. It may be a free flowing starch. For example, MWRutenberg, “St
arch and Its Modifications "pages 22-36, in Handbook
of Water-Soluble Gums and Resins, RL Davidson, M
See cGraw Hill, Inc., New York, 1980. If desired, starch can be converted with alpha-amylase to produce free-flowing starch by the method disclosed in US Pat. No. 4,726,957 by Lacourse et al. One or more of these conversion techniques may be used in combination. The conversion is typically performed after derivatization or cross-linking, but can also be done before or after enzymatic treatment. If high viscosity debranched starch is desired, it is not desirable to convert the starch.

If low viscosity debranched starch is desired, about 60
Preferred are starches such as waxy corn that have been converted to a water fluidity (WF) up to. Water fluidity is an empirical measure on a scale of 0 to 90 where fluidity is inversely proportional to viscosity.

For other products, the degree of substitution or conversion to the desired viscosity and functional properties can be utilized prior to or subsequent to enzymatic debranching. For example, when debranched starch is used as an emulsifier in food products, octenyl succinic acid derivatives (OSA starch) are preferred. Starch is treated with octenyl succinic anhydride to form a starch ester derivative containing 0.25-3.0 wt% octenyl succinate.

In a preferred embodiment of the present invention, the step after starch conversion is heating the aqueous dispersion of derivatized starch to gelatinize the derivatized starch. This gelatinization process completely or partially disrupts the association of the starch molecules within the starch granules, making the molecules more applicable to the enzyme and causing the enzyme to more easily and uniformly debran the starch molecule. After the starch slurry is gelatinized, the solids content, temperature and pH of the dispersion are adjusted to give maximum enzyme activity.

Optimal parameters for enzyme activity depend on the enzyme used. Thus, the enzymatic debranching rate depends on factors such as enzyme concentration, substrate concentration, pH, temperature, the presence or absence of inhibitors, and other factors. Depending on the type of enzyme or its source, various parameters may need to be adjusted to achieve the optimal debranching rate. In general, enzymatic debranching is performed at the highest feasible solids content to facilitate subsequent drying of the starch composition while maintaining optimal reaction rates. For example,
The pullulanase (pull) used in the present invention to produce starch suitable for use as a fat substitute.
For ulanase) pre-cooked starch dispersions in the range up to 28% solids are preferred.

Those skilled in the art will appreciate that when gelatinizing a higher solids starch system (eg, about 50% solids) in a process that provides sufficient mixing to evenly mix the enzyme and starch at high solids, It will be appreciated that the higher solids starch system of
Furthermore, those skilled in the art will also recognize that the temperature, treatment time and other parameters in the enzymatic debranching process must be adjusted to higher solids contents. Processes utilizing high solids dispersions are within the scope of this invention and can be used to make the modified starches of this invention.

According to the method of the present invention, pullulanase (EC3.2.
1.41, which is explained using pullulan 6-glucanohydrolase, but isoamylase (isoamy)
lase, EC3.2.E.68), etc., showing selectivity for the degradation of 1,6-bonds of starch molecules, such that the 1,4-bonds are virtually completely eliminated and short-chain amylose is obtained. −
The α-1,6-DG glucanohydrolases can be used to produce the debranched starch of the present invention.

In a preferred embodiment, the enzyme used is pullulanase, a thermostable debranching enzyme obtained from a new species of Bacillus. This pullulanase catalyzes the hydrolysis of the α-1,6-bond in pullulan, provided that there are at least two glucose units in the side chain. Pullulan is a linear polymer consisting essentially of D-glucopyranosyltriose units linked by α-1,6-bonds.

Optimal concentrations of enzyme and substrate are determined by the level and activity of the enzyme activity, which depends on the source and type of enzyme and the concentration of enzyme in the commercial batch. While the process of the present invention utilizes the enzyme in solution, the process utilizing the enzyme immobilized on a solid support is:
It is within the scope of the present invention.

This reaction proceeds in the presence of buffer to ensure that the pH is at the optimum pH level throughout the degradation. Buffers of acetate, citrate or other weak acid salts are applicable. Other agents can be used to optimize enzyme activity. This reaction is performed at a temperature of 60 ° C. and the enzyme is Bacillus pullulanase,
PH range of 3.0-7.5, preferably 4.5-5.5, optimally 5.
Done at 0.

Aqueous starch dispersions have a pH of 5.0
The temperature should be maintained between 25 and 100 ° C., preferably 55 to 65 ° C., optimally 60 ° C. for enzymatic debranching. However, if a shorter processing time is desired,
A temperature range of 60-65 ° C or higher enzyme concentrations can be used. Alternatively, higher temperatures may be utilized if a thermostable enzyme that provides short chain amylose from starch is selected for use in the present invention. With respect to other parameters that define enzyme activity, the preferred and optimal temperature ranges will vary with other parameters such as substrate concentration, pH and other factors, and can be determined by one of ordinary skill in the art.

Enzymatic treatment is continued until the desired level of debranching is reached. The progress of enzyme treatment can be measured by various methods. If all critical parameters have been established for achieving a particular starch composition, the process will eventually proceed to a predetermined relative end point. This endpoint may be measured by change in viscosity, by gel permeation chromatography, content of reducing groups, by iodine reaction or by other methods known in the art to measure the extent of enzymatic debranching of starch molecules. You can

In a preferred embodiment, the debranching endpoint is 22 ° C. using the funnel viscosity method described in Example 1 below.
It is measured by measuring the viscosity of the starch dispersion at (72 ° F). The funnel viscosity method is a quick and simple method of measuring viscosity which records the amount of time it takes for a standard amount of starch slurry to flow through a standard size funnel.

In a second preferred embodiment, the degree of starch debranching is measured by gel permeation chromatography. After separating starch by gel permeation chromatography into different molecular weight fractions, the% short chain amylose is determined by calculating the weight% of the partially debranched starch eluted in the low molecular weight fraction.
It will be appreciated by those skilled in the art that these percentages are approximately equal to the amount of short chain amylose released from amylopectin by debranching enzyme. Experimental error in gel permeation chromatography (eg,
Sucrose or dextrin introduced enzymatically or with starch, due to contamination with enzyme solutions, buffers or other process components) results in short-chain amylose up to about 5% greater than short-chain amylose in starch samples.

The degree of starch debranching required for a particular application depends on the type of starch utilized, the presence and nature of the substituents and in some cases the degree of conversion. One of ordinary skill in the art will be able to select a suitable starch and with minimal experience determine the pruning required for a particular end use.

Although any amylopectin-containing starch can be utilized, the effect of partial enzyme debranching becomes more severe as the amylopectin content increases. Therefore, all commercially available starch can be used in the present invention,
Waxy corn containing 100% amylopectin is preferred. Up to 80% of waxy corn can be debranched to short chain amylose. Other starch
Less than 80% can be debranched and debranching must be controlled to leave at least 20% partially debranched amylopectin.

In a preferred embodiment, waxy corn or other waxy starch (eg, waxy rice or barley starch) is partially debranched and short chains sufficient to form a thermoreversible gel in an aqueous starch dispersion. Obtain amylose. The starch consists of 25-70% short chain amylose, preferably 35-65% short chain amylose. Equal debranching of waxy starches is preferred to impart a fatty, lubricious texture to the aqueous starch dispersion. Converted waxy starches (eg, 50WF acid converted waxy corn or waxy rice) are also preferred for making thermoreversible gels and providing fat-like properties in aqueous starch dispersions.

For making high strength starch gels, a partially debranched and cornstarch consisting of 10-45% short chain amylose, preferably 15-40% short chain amylose is desirable.

For producing water-insoluble films, the suitable amount of debranching enzyme decreases as the content of long-chain amylose in starch increases. For potato starch,
At least 20% short chain amylose must be provided. At least 25% for tapioca starch
For short chain amylose and waxy maize starch, at least 25% short chain amylose is preferred.

Unmodified or converted debranched waxy starches are preferred to produce a stable, opaque haze in the starch dispersion. 20 for waxy corn starch
Debranching is continued until ~ 65%, preferably 30-65% short chain amylose is produced. For acid-converted waxy corn starch, it is preferred to debranze to produce 30-55% short chain amylose.

After reaching the desired degree of starch debranching, the enzyme can be inactivated. Pullulanase
Instantly inactivates at temperatures above about 70 ° C, so this reaction brings the temperature of the starch dispersion to about at least 75 ° C.
It can be stopped conveniently by raising it for 15 minutes.

If the end use application requires starch purification, reaction impurities and byproducts can be removed by dialysis, filtration, ion exchange methods, centrifugation or other methods known in the art for isolating and recovering starch. it can.

If dried starch is desired for the end use application, the starch can be dehydrated by any method known in the art.

It should be understood that the present invention includes any starch containing partially debranched starch. Accordingly, the present invention includes blends of partially debranched starch and chemically modified starches and other polymers, etc., and enzymes are used in one step to partially branch starch. It also includes other steps of cutting. For example, the invention includes starch blends as well as other step processes in which starch is converted, derivatized, cross-linked or otherwise modified in addition to being partially enzymatically debranched. is there.

Examples The following examples describe embodiments of the invention in more detail. In the examples below, all parts and percentages are given on a dry weight basis and all temperatures are given in degrees Celsius, unless stated otherwise.

Example 1 This example illustrates the production of a representative partially debranched starch by the method of the present invention.

Starch was operably converted, derivatized, or crosslinked prior to gelatinization and treatment with pullulanase. To convert the starch, 100 parts of a slurry in 150 parts of water was heated to 52 ° C, the indicated amount of hydrochloric acid (1.75%) was added and the mixture was stirred at 52 ° C for 16 hours. This mixture was adjusted to pH 5.5 with alkali (3% sodium hydroxide solution).
The hydrolysis was stopped by neutralization to The converted starch was collected by filtration, washed and dried.

To prepare starch-derivatized octenyl succinate derivatives, 100
1 part starch is slurried in 150 parts water, the pH is adjusted to 7.5 with sodium hydroxide and the pH is adjusted to 7.5 with alkali.
Slowly added the indicated amount of octenyl succinic anhydride while keeping at. The reaction was complete when no additional alkali was needed. The pH was adjusted to 4.0-6.5 and the resulting derivative was collected by filtration, washed and dried.

In order to produce the acetate derivative, 100 parts of starch was slurried in 150 parts of water, the pH was adjusted to 8.3 with sodium hydroxide, while maintaining the pH at 8.3 with the above alkali,
Slowly and the indicated amount of acetic anhydride was added.
The reaction was complete when no additional alkali was needed. The pH was adjusted to 4.0-6.5 and the resulting derivative was recovered as above.

Slurry 100 parts starch in 150 parts water, add 0.8 parts sodium hydroxide, 1.0 parts sodium chloride,
Crosslinked starch was then prepared by adding the indicated amount of phosphorus oxychloride. This slurry at room temperature for 3
Stir for hours. When the reaction was complete, the pH was adjusted to 5.5 with acid. The starch was collected by filtration, washed and dried.

Starch Debranching Aqueous slurry (20-30 solids) was prepared utilizing the desired starch. Add this aqueous starch slurry to about 149 ° C (3
The starch was gelatinized by jet steaming at 00 ° F).
58-60 ° C with constant stirring of the steamed starch dispersion
And placed in a constant temperature bath. The pH was adjusted to 5 with 3% hydrochloric acid.

Depending on the type of starch used and its amylopectin content, 0.5-10.0 ml of pullulanase per 100 g of starch was added to this cooked starch dispersion. The pullulanase used (EC 3.2.2 41 pullplan 6-glucanohydrolase) is a starch debranching enzyme produced from a new species of Bacillus. This enzyme (Promozyme ^™ ) is obtained from NOVO Industri A / S, Denmark. The enzyme activity of a 1.25 g / ml solution of Promozyme is 2
Normalized in a solution of 00 PUN / ml. 1 PUN (pullulanase unit NOVO) is the amount of enzyme that, under standard conditions, hydrolyzes pullulan and eliminates reducing hydrocarbons with a reducing power equal to 1 micromol glucose per minute. The method of measuring PUN is available from NOVO Industri A / S.

Therefore, in a starch dispersion utilizing corn starch, 125 PUN pullulanase per 100 g corn starch is added to the dispersion. For waxy corn starch slurry (indicating higher amylopectin content), 750 PUN pullulanase per 100 g of waxy corn starch is added to the dispersion.

The amount of debranching was measured first by a funnel viscosity test followed by gel permeation chromatography.

Funnel Viscosity Measurement To determine the funnel viscosity at 19% solids, 38 g of starch (anhydrous basis) was weighed into a 250 ml weighing beaker (stainless steel) containing a thermometer and 20 times with distilled water.
The total weight was 0 g. The sample was mixed to dissolve all lumps and heated or cooled to 72 ° F (22 ° C). A total of 100 ml of cooked starch dispersion was metered into a graduated cylinder. It was then poured into a graduated funnel using the fingers to close the pores. A small amount was flowed to the graduated container to remove trapped air and any remaining residue in the graduated container was returned to the funnel.
A timer was used to record the time it took for the 100 ml sample to flow from the funnel tip.

The funnel was a standard 58 °, thick, heat-resistant glass funnel with a top diameter of 9-10 cm and a barrel inner diameter of 0.381 cm. The funnel was measured to flow 100 ml of water for 6 seconds using the method described above.

Corn Starch (Caustic) Funnel Viscosity Due to the starch breakage that occurs when corn starch is used, the funnel viscosity measurement above was modified as follows for debranched corn starch.

1. Reduce starch sample weight to 15g (anhydrous basis); 2. Add hot enough water (at least 90 ° C) to the starch to make a total amount of 150g; 3.15g of 25w / v% sodium hydroxide solution Add to hot starch slurry; and 4. Cool the slurry to 22 ° C. (72 ° F.) with stirring and make the measurements as described above.

Gel Permeation Chromatography For analysis, prepare starch by slurrying 5 mg starch in 4 ml dimethyl sulfoxide (“DMSO”) containing 0.3 M sodium nitrate and heating the slurry to 80 ° C. for at least 30 minutes. did. Sample (20
0ul) to the ALC / GPC-150C chromatograph (Water Associat
es, Milford, Massachusetts, Nelson 3000 Series Chromatography Data System and PL Gel Mix 10ul
Column (Polymer Laboratory, Amherst, Massachusetts
(State) was injected using DMSO containing 0.03 M sodium nitrate as a mobile phase and eluted at a rate of 1 m1 / min. This column was loaded with a dextran standard (Pharmacia Ch
emicals, Piscataway, New Jersey, Mw 2,000; 20,
000; 80,000; 500,000; and 2,000,000). The% short chain amylose was calculated from the relative areas of the peaks obtained within the molecular weight range of about 500-200,000.

Preparation of Debranched OSA Waxy Corn Starch Produced by reacting the OSA starch derivative with 4000 g of waxy corn and 1% anhydrous octenyl acetic acid utilizing the method described above. This starch was then jet cooked at pH 5.0 to give a 23% starch dispersion. Pullulanase (80 mls) was added to this dispersion at 58 ° C with stirring. After 24 hours, the funnel viscosity was 19% solids and 22 ° C (72%
It was 35 seconds at ° F).

Further debranching was continued by adding an additional 80 mls of pullulanase at 58 ° C and stirring the dispersion for a further 3 hours. About 80 ℃
The pullulanase was inactivated by heating this dispersion. The funnel viscosity is 19% solids and 22 ° C (72%
12 seconds at ° F). The starch dispersion was spray dried at an inlet temperature of 200-210 ° C and an outlet temperature of 80-90 ° C. The spray dried starch was screened through a 40 mesh screen.

A second sample of OSA waxy corn (4000 g) was prepared and debranched in the same manner as the first sample except 20 mls of pullulanase was utilized in a single addition. Debranching was continued for 2 hours, with a funnel viscosity of 10% solids and 22 ° C.
It became 50 seconds at (72 ° F). This sample was spray dried in the same manner as the first sample.

Example 2 This example illustrates the use of the enzyme isoamylase (glycogen 6-glucano-hydrolase; EC3.2.68) to produce partially debranched starch.

24% steamed waxy corn starch (2,500g)
5,000 units of Pseudomonas amylode solid dispersion
ramosa isoamylase (Sigma Chemica)
l Company, St. Louis, Missouri). One unit of this isoamylase causes an increase in absorbance (A ₆₁₀ ) of 0.1 in 1 hour using rice starch as the substrate.

The starch dispersion was heated to 45 ° C at pH 4.0, the enzyme was added, and the mixture was stirred for 26 hours. A portion of the mixture was removed, heated to 80 ° C. to inactivate the enzyme and spray dried and sieved as in Example 1.
The remaining portion of the starch mixture was treated with the enzyme for a total of 43 hours, inactivating the enzyme and the starch was dried and sieved as described above.

The amount of short chain amylose obtained from isoamylase hydrolysis was measured by gel permeation chromatography. The 26 hour sample contained 21.9% and the 43 hour sample contained 28.4% short chain amylose.

Example 3 This example illustrates the relationship between processing time, funnel viscosity (or water fluidity) and% short chain amylose of the starch of the present invention.

The partial enzymatic debranching process of Example 1 was performed on the starches listed in Table 1.

The funnel viscosity and% short chain amylose were measured by the methods described above. The results are shown in Table I.

The results generally show that as the reaction time increases, the% short-chain amylose increases and the funnel viscosity decreases in a non-linear relationship. Therefore, one or more of these measurements can be used to measure the progress of enzymatic debranching.

Example 4 This example illustrates that the starch of the present invention can be utilized to produce a lubricious, fatty tissue in an aqueous starch dispersion.

Waxy corn starch was prepared by the method of Example 1
It was partially debranched at 72 ° F (10 ° C) and 10% solids (about 50% short chain amylose) to a funnel viscosity of 10-12 seconds.

The fatty or lubricating properties of starch were evaluated by dispersing 25 g anhydrous starch in 75 g distilled water.
The dispersion was heated on a steam bath for 20 minutes, poured into Petri dishes, refrigerated for 1 hour and evaluated subjectively. Spread this partially debranched starch gel on your palm and
And it was observed that it had lubricity and a creamy touch. The gel was glossy and opaque.

Example 5 This example illustrates that the starch of the present invention can be used in film forming applications.

Waxy corn starch was prepared by the method of Example 1
It was partially debranched at 72 ° F (19 ° C) and 19% solids (~ 50% short chain amylose) to a funnel viscosity of 10 seconds. Acid-converted (85WF) waxy corn starch (viscosity approximately equal to this debranched starch) was compared to this debranched starch.

The film was prepared by forming a film on the glass plate by impregnating a 2 ″ × 8 ″ glass plate with an aqueous dispersion of debranched waxy corn starch (25% solids). The glass plate was removed from the dispersion and dried overnight at room temperature. An opaque film formed which was re-soaked at room temperature and did not dissolve even with gentle rubbing.

A similar film was made from 85WF acid converted waxy corn. After drying, the film was transparent. Upon re-soaking in water, the film dissolved.

Example 6 This example illustrates that the starch of the present invention can be used to form a stable, opaque or translucent haze when dispersed in an aqueous medium.

Waxy corn starch and acid-converted (50W
F) Waxy corn starch was debranched by the method of Example 1 to the funnel viscosity shown in Table II.

In addition, tapioca starch was debranched to a funnel viscosity of 54 seconds (10% solids). This tapioca dispersion was passed through a hand homogenizer before measuring the transmittance. For purposes of comparison, fully debranched crystalline short-chain amylose prepared by the method claimed in U.S. Pat.No. 3,730,840 was dispersed in distilled water at 1.0% solids and the permeation of this dispersion was performed. The rate was measured.

The light transmission of a 1% solids starch dispersion in distilled water (0.2% solids for tapioca) was measured initially and after 24 hours using a Brinkman PC800 Colorimeter.
The results are shown in Table II. The% light transmission decreased as the haze-forming ability of starch was improved. The significant decrease in% light transmission after 24 hours indicates that the starch haze is not stable.

Waxy corn starches that were debranched to give 20-60% short chain amylose produced the most stable haze. Well-debranched starch (US Pat. No. 3,730,840) did not form a haze.

Example 7 This example demonstrates the use of the starch of the present invention to form a heat irreversible gel.

Waxy corn starch and acid-converted (50W
F) Waxy corn starch was debranched by the method of Example 1 to the funnel viscosity shown in Table III.

The following starches were also used in Example 1 up to the funnel viscosity shown below.
The branches were cut by the method of.

K: acid converted (50WF) tapioca-43.1 seconds (10% solids); L: tapioca-54.2 seconds (10% solids); and M: waxy corn / tapioca 80/20 mixture-137 seconds (10
% Solids).

In addition, for comparison purposes, a fully debranched, crystalline short chain amylose product was prepared by the method claimed in US Pat. No. 3,730,840.

These thermoreversible gel forming properties were evaluated by dispersing 25 g anhydrous starch in 75 g distilled water. The dispersion was heated on a steam bath for 25 minutes, poured into Petri dishes, refrigerated for 1 hour and subjectively evaluated for gel formation. The resulting gel is thermoreversible when fluidized when reheated on a steam bath and re-formed when left at room temperature.

The results of gel evaluation are listed in Table III. U.S. Pat.No. 3,37
The substance produced by the method described in No. 0,840 is
No gel was formed. A debranched waxy corn sample containing about 30-64% short chain amylose formed a thermoreversible gel. Similar gel has acid conversion (50WF)
Obtained from debranching waxy corn starch, acid converted (50WF) tapioca starch and 80/20 waxy corn / tapioca blend. Tapioca starch formed a gel that was not thermoreversible.

Example 8 This example illustrates that the gels of the present invention can be used to form high strength gels.

Corn starch was debranched by the method of Example 1 to the funnel viscosity listed in Table IV and the starch dispersion was adjusted to 5 or 10% solids. An unmodified corn starch slurry was produced and jet steamed by the method of Example 1.
After boiling, the starch dispersion was adjusted to 5 or 10% solids. A comparative sample (unmodified cornstarch) and a sample made from starch A were refrigerated for 60 hours. Debranched starches B and C were refrigerated for 1 hour. Gel strength (grams) at a speed of 0.5 mm / sec using a 1/2 ″ diameter cylinder (Probe TA-5) Stevens L.FR
A. Measured with Texture Analyzer. The results are shown in Table IV.

Unmodified cornstarch did not form a gel at 5% solids. 10% solids sample is a weak gel (9 grams)
Was formed. In contrast, all the partially debranched cornstarch samples had very strong gels (175-550 grams) at 10% solids, even after just 1 hour of refrigeration.
A strong gel (40-250 grams) was formed at% solids.

Example 9 This example illustrates that various starches can be utilized in the present invention.

The partially enzymatic debranching process of Example 1 was performed on the following starches.

A.13 PUN pullulanase / g starch 0,1.0,5.0 and 2
Corn starch blanched for 4.0 hours; and 12 seconds (22
Corn starch debranched to a funnel viscosity of 10% solids at 72 ° F (72 ° F).

B.13 PUN pullulanase / g Tapioca starch (21% solids) debranched with starch for 0,0.25,1.0,2.0 and 5.0 hours.

C.13 PUN pullulanase / g potato starch (18% solids) debranched with starch for 0,0.25,1.0,4.0 and 16.0 hours.

The funnel viscosity and% short chain amylose were measured by the methods described above. Subjective observations of starch properties were made by the method described in Examples 4-7 above. Acid converted (32WF) tapioca was also observed for comparison purposes. The results are shown in Table V.

Example 10 This example illustrates that various partially debranched starch derivatives can be produced by the method of the present invention.

The derivatization reaction and the partial debranching process were performed as in Example 1 for the starches listed in Table VI.

Claims (1)

[Claims] 1. A) providing a pregelatinized starch, b) said starch until said starch consists of up to 80% by weight of short chain amylose and at least 20% by weight of partially debranched amylopectin. Alpha-1,6-D
An alpha-1,6-D-glucanhydrase (alpha-1,6-gluacnh) whose glucoside bond is selected from pullulanase and isoamylase
ydlase) hydrolyzing, and c) recovering a starch consisting of up to 80% by weight of short-chain amylose produced and at least 20% by weight of partially debranched amylopectin, 80% by weight capable of forming thermoreversible gels or high strength gels or stable, opaque, cloudy, or lubricious fatty structures or combinations thereof in aqueous dispersions
An enzymatically debranched starch consisting of up to short chain amylose and at least 20% by weight of partially debranched amylopectin.