JP2006131772A - Method for producing denatured starch with controlled thermal swelling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To relatively easily produce denatured starch with controlled thermal swelling by solving such conventional problems that, upon heating a starch suspension, starch particles swell at a certain temperature, causing rise of viscosity and collapse of the particle and resulting in viscosity lowering (breakdown), such starch causing breakdown is not suitable for food grade paste such as soup, flour paste and jam and starch with controlled thermal swelling has been used for the purpose; while for adhesive paste in industrial use such as stationery paste and wallpaper paste, one with stringiness affects workability and the one with low stringiness has been preferably used; as the starch thus varied of viscosity, crosslinked starch in which swelling of starch is chemically suppressed, dry heat-treated starch and wet heat-treated starch in both of which starch is physically denatured are illustrated, however, among these physically denatured starch, dry heat-treated starch causes discoloring due to heat and affects quality of the final product using it, while wet heat-treated starch requires use of a machine with highly complicated structure since it undergoes a high temperature heat treatment under pressure. <P>SOLUTION: This method for producing the denatured starch with controlled thermal swelling comprises dispersing starch in a polar solvent aqueous solution containing 5-20 mass% polar solvent and 15-30 mass% water both based on the starch and heating the dispersion at a temperature of the gelatinization starting temperature or above but below 100°C. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a modified starch in which thermal swelling is suppressed, and more specifically, a polar solvent aqueous solution containing 5 to 20% by mass of a polar solvent and 15 to 30% by mass of water is dispersed in the starch. It is related with the manufacturing method of the modified starch characterized by being obtained by heating this above gelatinization start temperature or more and less than 100 degreeC.

Conventionally, as a method of suppressing thermal swelling of starch, there has been a method of chemically crosslinking using a crosslinking agent such as epichlorohydrin, glyoxal, trimetaphosphoric acid or the like. On the other hand, dry heat treatment and wet heat treatment have been proposed as methods that do not use a crosslinking agent.

  Dry heat treatment includes a method in which the granular starch or flour is substantially anhydrous and then heat treated (Japanese Patent Publication No. 9-503549), and a method in which the starch / oligosaccharide blend is substantially anhydrous and then heat treated. (Special Table 2003-501494).

In addition, as the wet heat treatment, both a decompression line and a pressurized steam line are provided, and starch is placed in a container that can be sealed with pressure resistance for both internal and external pressures. ) And then cooling (Patent No. 2996707) or a method of dispersing and suspending starch in an ethanol solution having a water content of 25 to 60% by volume and heating it to 100 to 130 ° C. (Patent No. 1). 3365656).
JP-T 9-503549 Special table 2003-501494 gazette Japanese Patent No. 2996707 Japanese Patent No. 3365656

  Conventionally, when a starch suspension is heated, starch particles swell at a certain temperature, resulting in an increase in viscosity and a decrease in viscosity (breakdown) due to the collapse of the particles. However, starches that cause breakdown are not suitable for food pastes such as soups, flour pastes, and jams, and starches that suppress thermal swelling have been used. On the other hand, for industrial use, as pastes such as office glue and wallpaper paste, those having spinnability are poor in workability, and those having low spinnage have been preferred and used. As the starch having such a viscosity changed, a cross-linked starch in which the swelling of the starch is chemically suppressed using a cross-linking agent, or a wet-heat-treated starch or a specially modified one as disclosed in JP 9-503549 A, The dry heat-treated starch which heat-processed in the anhydrous state after adjusting the starch or starch-oligosaccharide blend body described in the Japanese translations of PCT publication No. 2003-501494 etc. to neutrality or more is mentioned.

  Among the physically modified starches, the starch that has been subjected to the dry heat treatment is colored by heat, which affects the finish of the final product using the starch. In addition, the wet heat-treated starch is subjected to pressure and heat treatment at a high temperature, and therefore a machine having a very complicated structure must be used.

In order to solve this problem, the present inventors have dispersed a polar solvent aqueous solution containing 5 to 20% by mass of a polar solvent and 15 to 30% by mass of water in starch as a result of intensive studies. It was discovered that heat-swelling-inhibited modified starch can be produced relatively easily by heating at a gelatinization start temperature of starch using this or higher and lower than 100 ° C., thereby completing the present invention.

  As described above, according to the present invention, the heat-swelling-inhibited modified starch is converted from starch to a polar solvent aqueous solution containing 5 to 20% by mass of a polar solvent and 15 to 30% by mass of water based on the starch. It can be produced relatively easily by dispersing and heating at a temperature not lower than 100 ° C. and higher than the gelatinization start temperature of the starch using this.

  Examples of starch that can be used in the present invention include potato starch, corn starch, sweet potato starch, tapioca starch, sago starch, rice starch, and amaranthus starch. And starch derivatives such as cross-linking, dry heat-treated starch, and wet heat-treated starch.

Examples of the polar solvent used in the present invention include methanol, ethanol, acetone and the like, as long as they contain one or more of these.

Content of the polar solvent of the polar solvent aqueous solution used by this invention should just contain 5-20 mass% with respect to starch. If the content is less than 5% by mass, starch is gelatinized during the heat treatment, which is not preferable. Moreover, when it exceeds 20 mass%, the effect by heat processing will not be acquired so much.

  The water content of the aqueous polar solvent solution used in the present invention may be 15 to 30% by mass with respect to the starch. When the content is less than 15% by mass, the effect of the heat treatment is not obtained so much, and when it exceeds 30% by mass, the starch is gelatinized during the heat treatment, which is not preferable. .

  The heating temperature performed by this invention should just be more than the gelatinization start temperature of the starch to be used, and less than 100 degreeC. For example, since corn starch has a gelatinization start temperature of about 70 ° C., the reaction may be performed at 70 ° C. or higher. If it is less than the gelatinization start temperature of the starch used, it will not become a heat-swelling type (low breakdown) starch. First, a machine with a very complex structure must be used.

The method for producing the heat-swelling-inhibited modified starch of the present invention can be carried out by the following method. First, an aqueous solution containing 5 to 20% by mass of a polar solvent and 15 to 30% by mass of water with respect to starch is prepared and dispersed in starch. At this time, when the dispersion amount of the aqueous solution is 20 to 50% by mass with respect to the starch, the stirring of the starch during the heat treatment is relatively successful, and it becomes difficult to form a lump (so-called lumps) during the production. Then, what is necessary is just to heat product temperature to gelatinization start temperature or more and less than 100 degreeC using a stirrer with a jacket, or a kneader. At this time, it is not necessary to seal the stirrer or the like, and it may be returned to the reaction system using a reflux tube or the like. In the heat treatment, the temperature and time may be appropriately adjusted according to the amount of the polar solvent added until the starch is thermally inhibited.
Thereafter, ordinary treatments such as drying, fine powder, and sieving are performed to obtain a modified starch.

EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited only to these Examples.

To 100 parts by mass of corn starch (hereinafter referred to as “parts”), an aqueous solution in which the amount of polar solvent described in Table 1 and 25 parts of water were mixed was added, and the mixture was stirred for 30 minutes with a jacketed stirrer. Thereafter, the jacket temperature was heated to 85 ° C. and heat treatment was performed for 4 hours. As a comparison, 30 parts of water was added to 100 parts of corn starch, and the same treatment was performed. The obtained mixture was dried and refined, and the viscosity was measured using a Viscograph manufactured by Brabender Co., Ltd., and the breakdown was compared. The untreated corn starch was also measured in the same manner.
The viscosity measurement conditions are as follows.
Measurement concentration: anhydrous 8%, total amount 450 g Stirring speed: 75 rpm Cartridge sensitivity: 700 cmg
Temperature condition: Start at 50 ° C. Temperature rise to 95 ° C. (1.5 ° C./min) Hold for 10 minutes The breakdown is expressed as (peak viscosity) − (viscosity after 10 minutes at 95 ° C.) and used as an index of thermal swelling. In other words, it is considered that the smaller the value, the more effective the thermal swelling suppression. The results are shown in Table 1.

  From Table 1, the modified starch obtained by dispersing and heating an aqueous solution containing 5 to 20% by mass of ethanol with respect to starch had a thermal swelling inhibiting effect. Moreover, the thing which added only water and did not contain ethanol, and the unprocessed starch were quite large like breakdown.

  An aqueous solution in which 10 parts of ethanol and 25 parts of water were mixed was added to 100 parts of corn starch, and heat treatment was performed in the same manner as in Example 1 except for the heating temperature described in Table 2. The obtained mixture was refined, and the viscosity was measured under the same conditions as in Example 1 using a Brabender Viscograph, and the breakdown was compared. In addition, it measured similarly about unprocessed starch. The results are shown in Table 2. In the table, when there was no peak, “NIL” was assigned.

  From Table 2, it was found that the breakdown started to decrease from 70 ° C., which is higher than the gelatinization start temperature, but that the thermal swelling suppression effect is noticeable at 75 ° C. or higher. It was also found that at 98 ° C., the viscosity after 10 minutes at 95 ° C. was too low with respect to the concentration.

An aqueous solution obtained by mixing 10 parts of ethanol and 25 parts of water was added to 100 parts of the starch shown in Table 3, and heat treatment was performed in the same manner as in Example 1. The obtained mixture was refined, and the viscosity was measured under the same conditions as in Example 1 at the concentrations shown in Table 3 using a Brabender Viscograph, and the breakdown was compared. In addition, it measured similarly about unprocessed starch. The results are shown in Table 3.

表中上段：未処理澱粉 下段：加熱処理後の澱粉

Upper row in the table: untreated starch Lower row: starch after heat treatment

  From Table 3, it was found that the starch excluding waxy corn starch has a thermal swelling inhibiting effect. Those using waxy corn starch have a smaller breakdown than untreated starch, but are larger than other starches.

<Acid resistance test>
An anhydrous 8% suspension was prepared using 10 parts of ethanol prepared in Example 1, adjusted to each pH, and heated to 85 ° C. or higher for 10 minutes. After the moisture correction, the paste solution was cooled to 30 ° C., and the viscosity was measured with a B-type viscometer at 30 rpm. As a comparison, the viscosity of untreated corn starch was measured under the same conditions. The results are shown in Table 4.

  From Table 4, it was found that viscosity stability at a low pH, which is not found in the raw material starch, was imparted.

Claims (2)

A polar solvent aqueous solution containing 5 to 20% by mass of a polar solvent and 15 to 30% by mass of water is dispersed in starch, and heated at a gelatinization start temperature of starch or less than 100 ° C. using the starch. A method for producing a heat-swelling-inhibited modified starch characterized by being obtained. The method for producing a heat-swelling-inhibited modified starch according to claim 1, wherein the polar solvent is at least one solvent selected from methanol, ethanol, and acetone.