JP2819340B2 - Method for separating amylose and amylopectin - Google Patents

Description

The present invention relates to a method for industrially separating (concentrating) and purifying an amylose component and an amylopectin component from ordinary starch. The present invention also relates to a method for concentrating amylose or amylopectin from ordinary starch.

[Conventional technology and problems to be solved]

Amylose and amylopectin are used in the fields of foods, pharmaceuticals, adhesives and the like.

For example, amylose is used in water-resistant paste and starch film, meat processing as a food material, fish paste products, tempura and fried clothing for frozen food, vegetable juice, confectionery, bread making, noodle making, etc. Widely used as stabilizers for rice crackers, ready-to-eat foods and frozen desserts.

Hitherto, high amylose starch and glutinous starch improved by breeding and the like, for example, special starches such as glutinous rice and waxy corn have been used.

As a method of separating amylose and amylopectin from general starch, warm water extraction method, complex formation separation method,
Salt fractionation and enzymatic methods have been used.

The hot water extraction method involves stirring and extraction using warm water slightly higher than the gelatinization temperature of the starch, and the complex formation separation method uses a reagent that easily forms a complex with amylose, such as 1-butanol or thymol. In this method, the components are precipitated and separated from amylopectin. In both cases, the treatment can be carried out only at a low starch concentration of 2 to 3%, and the purification of amylose and amylopectin after separation is extremely troublesome, so that both are not industrially suitable.

Salt fractionation is a method in which a starch slurry containing a salt, for example, magnesium sulfate, calcium chloride or the like, having a starch concentration of about 10% is gelatinized at 160 ° C. under pressure, and the difference in precipitation temperature is used to separate amylose and amylopectin. This method is already industrialized,
A large amount of salts is required, and at 160 ° C. or higher, there are problems such as coloring problems.

The enzymatic method uses amylopectin α by isoamylase.
This method selectively cleaves 1,6 bonds to make all linear molecules, that is, amylose, and does not require high-temperature treatment. The yield is 95% or more, but high-concentration treatment cannot be performed. In addition, since an enzyme is used, strict temperature control is required, the treatment time is longer than in other methods, and it takes 1-2 days for the enzyme reaction.

On the other hand, a method for producing high amylose starch using a high-pressure extruder is disclosed in JP-B-51-22059 and JP-A-63-610.
Many publications, such as the 01 publication, are disclosed. In addition, Japanese Patent Publication No. 54-16
Japanese Patent No. 576 discloses that starch is gelatinized and then freeze-treated to obtain a porous starch suitable for a high amylose food material. In addition, Japanese Patent Publication No. 54-23
No. 970 describes a method for producing a high-temperature treated food by an autoclave.

All of these methods use a special and expensive high-amylose starch as a raw material, so that considerable costs are required.

J. Cereal Science by C. Mestres et al.
7 (1988) 123-134, it is reported that in cooking using a high-pressure extruder, amylose and amylopectin are entangled at the molecular level, making it difficult for amylose to recrystallize and lowering the gelatinization temperature.

However, gelatinization by a high-pressure extruder is similar to the apparatus and cooking conditions of the present invention, but the precipitate of starch paste liquid gelatinized by the extruder according to the report described above is a co-crystal substance of amylose and amylopectin. Was confirmed. For this reason, the amylose component cannot be concentrated by the extruder.

Accordingly, an object of the present invention is to provide a method for industrially and efficiently separating and / or concentrating amylose and amylopectin from ordinary starch without using special and expensive high-amylose starch as a raw material. It is in.

The present inventors have conducted intensive studies to achieve the above object, and as a result, by using a static mixer, if normal starch is treated at a temperature of 160 ° C. or more and a saturated vapor pressure or more and a pH of 4 to 9, sufficient gelatinization will be obtained. The present inventors have found that an appropriate low molecular weight can be achieved and that the amylose component can be selectively recrystallized and separated, and the present invention has been achieved.

 Hereinafter, the present invention will be described in detail.

The starch to which the present invention can be applied includes various natural starches,
A wide range of starches can be used, such as processed starches, unless otherwise limited by end use.

As the natural starch, various starches such as corn, rice, wheat, potato, sweet potato, tapioca and the like can be used.

As the processed starch, various acid-treated starches, oxidized starches, esterified starches, cationic starches and the like can be used, but naturally there are those which cannot be used as components in the final use, for example, in the use form of foods and pharmaceuticals. Conceivable.

The present invention is carried out at 160 ° C. or higher, preferably 160-210 ° C. If the temperature is lower than 160 ° C., the molecular chain is not sufficiently cleaved, and the size liquid gels, so that a precipitate mainly composed of amylose components cannot be obtained. On the other hand, if the temperature is higher than 210 ° C., excessive decomposition occurs, and the amount of the precipitate decreases.

The pressure is equal to or higher than the saturated vapor pressure. In the present invention, in order to prevent a gaseous phase portion from being generated in a static mixer, which will be described later, conditions that are higher than the saturated vapor pressure are required.

The starch concentration may be any concentration at which the starch can be dispersed in water and can be transported, but a higher concentration is desirable in view of processing efficiency. For example, 30% to 60%.

The starch slurry needs to be weakly acidic to weakly alkaline, and the present invention is carried out at pH 4-9. The ungelatinized starch washed with acid during the purification process is less acidic than pH 4 at the above-mentioned starch solid concentration. When the acidity becomes stronger than pH 4, the starch molecules are excessively decomposed, and no precipitate can be obtained. On the other hand, if the acidity is weaker than pH 9, the viscosity of the size liquid becomes high, and it becomes difficult to separate the precipitate.

Generally, the processing time is between 5 and 150 minutes. Shorter treatment times result in a bulky precipitate and a slightly lower amylose content. Longer treatment times tend to result in finer precipitates and increase the amylose content, but decrease the amount of precipitates themselves.

The present invention is performed using a static mixer. In this static mixer, an aliment for stirring is fixed in the apparatus. Therefore, in this apparatus, the starch in the slurry does not settle, and gentle stirring sufficient to uniformly heat the mixture is performed. Not mixed. Therefore, amylose is selectively crystallized and easily precipitated. In this respect, the extruder is sufficiently mixed, so that amylose and amylopectin are co-crystallized, making separation difficult. The static mixer may be any as long as it has a predetermined pressure, a pressure resistance of at least 19 kg / cm ² or more, and can be uniformly heated at 160 ° C. or more.

The starch paste liquid thus obtained is quenched or allowed to cool to crystallize low-molecular-weight amylose, and to purify a precipitate having a high amylose content containing the same as a main component. When stored at 0 to 4 ° C. after cooling, a precipitate can be obtained efficiently, but after standing for one day, the content of the precipitate in the entire size liquid hardly changes.

Observation of this precipitate with a polarizing microscope reveals a clear cross at the center of the particle. This polarized cross is not a concentric pattern as seen in the non-gelatinized starch, but is different from that before gelatinization, and it can be seen that it is a crystal.

The precipitate is then separated from the solution part. When cooled, the starch paste solution is diluted with water to lower the viscosity and precipitate and separate the precipitate. In addition, those conventionally used for such separation, such as centrifugal sedimentation and sentry cleaner, can be used. Then, after drying as needed, you may grind.

If necessary, additives such as an antioxidant and a thickener may be added to the starch paste liquid. If there is no heat denaturation, it can be used by adding it to the starch slurry before the treatment of the present invention.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to examples. However, the following examples do not limit the scope of the present invention at all. In addition, all solid content concentrations were represented by weight percent (%).

Example 1 A starch slurry prepared by dispersing raw corn starch (corn starch) in water so as to have a solid content of 25% was heated to 160 ° C. using a static mixer (diameter 12.7 mm, length 3760).
mm and discharge pressure in the reaction tube with stirring blades fixed inside.
The mixture was passed through a pump of 10 kgf / cm ^{2 at} a feed rate of 62.5 ml / min and treated for 40 minutes to obtain a starch paste liquid having a concentration of 25% and a B-type viscosity of 100,000 cp or more (30 ° C.). After leaving this starch paste liquid to cool and stand for 24 hours,
The solution was diluted with water to a solid content of 20%, and water-insoluble components were precipitated and separated. Table 1 shows the results.

Examples 2 to 7 and Comparative Examples 1 to 3 Corn starch or tapioca starch was treated with a static mixer in the same manner as in Example 1 under the conditions shown in Table 1. Table 1 shows the results.

From Table 1, it can be seen that the treatment of the present invention provides highly concentrated amylose from ordinary starch.

Claims (2)

(57) [Claims] 1. An amylose component comprising gelatinizing starch with water at a temperature of 160 ° C. or more and a saturated vapor pressure or more and at a pH of 4 to 9 using a static mixer, followed by cooling to separate the formed insoluble matter. A method for separating amylopectin. 2. Concentration of amylose by gelatinizing starch with water at a temperature of 160 ° C. or higher and a saturated steam pressure or higher and a pH of 4 to 9 using a static mixer, followed by cooling and separation of formed insolubles. Method.