JPH0697962B2 - Method for producing highly oil-absorbing porous powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a method for producing a porous powder using starch or cereal flour as a raw material and having a high oil absorption ability.

BACKGROUND ART Conventionally, liquid or semi-solid fats and oils have been used in large amounts in a very wide range such as foods, cosmetics and pharmaceuticals. However, liquids and semi-solids are inconvenient to handle, and
With the growing demand for diversified powder products in various product forms, there has been a need for a technique for powdering liquid or semi-solid fats and oils.

[Conventional technology and problems]

Several techniques have already been developed for powdering liquid or semi-solid fats and oils. For example, a method of encapsulating fats and oils using gelatin and the like, and a method of emulsifying the fats and oils with sugars, dextrins, proteins, emulsifiers and the like and then spray-drying are well known. However, these methods require expensive equipment and are not suitable for pulverizing a small amount of various kinds of fats and oils.

On the other hand, there is known a method of producing an oil-absorbing powder by using starch as a main component, and gelatinizing, drying and pulverizing the starch with an appropriate device and under appropriate conditions. Extruders and drum dryers are typical devices. However, under the present circumstances, the starch obtained by such a method is flaky and can absorb only about 2 ml of liquid oil per 1 g of starch. Further, a method for producing a non-gelatinized porous starch using a foaming agent is known, and the porous starch has a relatively large oil absorption property, but since the gelatinization is insufficient, it has a texture in food. There is a problem that it becomes worse and that cosmetics have a feeling of being crushed.

In view of the above-mentioned present conditions, the present inventors paid attention to the following points and conducted research.

(1) Liquid or semi-solid fats and oils can be powdered very simply by mixing without requiring an expensive device.

(2) Very high oil absorption (at least 1 g of starch
It must absorb 3 ml or more of liquid oil and be a powder).

(3) Starch or cereal flour containing 70% by weight or more of starch is used as a raw material, and the obtained powder is swollen and hydrated with water at room temperature.

By satisfying these conditions (1) to (3), it is possible to easily obtain a powder having a high oil-absorption capability, which can easily powder a liquid or semi-solid fat and oil and has no problem even when used in foods and cosmetics. It will be possible.

[Means for solving problems]

As a result of research conducted by the present inventors, when starch or a flour containing 70% by weight or more of starch has a degree of gelatinization of starch of 80% or more and becomes a porous powder under a certain specific condition, the above three The inventors have found that the conditions are satisfied and completed the present invention.

Method for obtaining highly oil-absorbing porous powder in which the degree of gelatinization of starch in the powder is 80% or more, the pore size of the powder is 1 to 15 μm, and the specific surface area is 3 to 15 m ² / g In, starch or flour containing 70% by weight or more of starch is heated by adding water or warm water,
It is characterized in that the starch is pregelatinized so that the degree of pregelatinization is 80% or more, and the pregelatinized product of the obtained starch or flour is rapidly frozen at a temperature of -30 ° C or lower, followed by drying and pulverizing. The present invention relates to a method for producing the above highly oil-absorbing porous powder.

The porous powder in the present invention exhibits a high oil absorption property because the pore diameter, that is, the diameter of the pores, is in the range of 1 to 15 μm. In particular, it is desirable that 80% or more of the total number of pores having a diameter of 3 to 10 μm be present. If the pore size is less than 1 μm, the oil absorption rate will decrease,
On the other hand, when it is larger than 15 μm, the oil and fat holding power is lowered and at the same time the powder property is lowered. However, in some cases, some of the porous powder is destroyed during production and there are pores with a diameter larger than 15 μm, and there are pores with a diameter less than 1 μm. If so, its existence is ok. In the present invention, the pore size was measured by a direct observation method using a scanning electron microscope.

The specific surface area of the powder is 3 to 15 m ² / g, preferably 5 to 13 m ² / g, and those having a specific surface area within this range exhibit high oil absorption. If the specific surface area is less than 3 m ² / g, the oil absorption capacity will be 2 ml / g or less, while if it is more than 15 m ² / g, the pore size will be too small and the oil absorption will be reduced. The specific surface area value in the present invention was measured by using an Oer type specific surface area meter using nitrogen gas.

The "highly oil-absorbing porous powder" in the present invention is a starch or a flour containing 70% by weight or more of starch as a raw material, subjected to various processes, dried, and pulverized, and has an oil absorption ability.
It means 3ml / g or more. The “oil absorption capacity” in the present invention is a value obtained by the following measuring method.

Measuring method: 10 g of oil-absorbing porous powder dried at 105 ° C for 1 hour
Take in a 0 ml glass beaker. Next, the rapeseed oil is dripped from the burette into the oil-absorbing porous powder while stirring and mixing with a glass rod. The amount of rapeseed oil dropped (m when the rapeseed oil exuded from the powder could not absorb oil and began to adhere to the beaker wall)
l) is defined as oil absorption capacity. Perform all operations at 20 ° C.

Ordinary raw starch, pregelatinized starch, and cereal flour have an oil absorption capacity of 0.5 m
l / g or less. On the other hand, the oil absorption capacity of the highly oil-absorbing porous powder according to the present invention shows a value of at least 3 ml / g or more.

The starch used as the raw material of the present invention is any starch that is used for food, and specific examples include corn starch,
Potato starch, sweet potato starch, rice starch, litter starch,
Examples include sago starch and tapioca starch. Further, dextrin obtained by hydrolyzing these with an enzyme or an acid may be used. However, since the oil absorption decreases as the degree of hydrolysis increases, those having a DE of 10 or less are preferable.

Also, flours containing 70% by weight or more of starch are suitable for use. Examples include wheat flour, barley flour, rice flour, buckwheat flour,
In addition to corn flour, potato flour, sweet potato flour, etc. may be mentioned.

The above-mentioned starch or cereal flour containing 70% by weight or more of starch may be used alone or in combination of two or more kinds. Further, edible ingredients other than starch, such as proteins, sugars and polysaccharides, can be used in combination as long as the oil absorption ability is not deteriorated, but it is necessary to contain at least 70% by weight of starch.

A preferred method for producing a highly oil-absorbing porous powder from starch or cereal flour containing 70% by weight or more of starch is as follows.

First, water or warm water is added to starch or cereal flour containing 70% by weight or more of starch and heated to 70 ° C. or higher to gelatinize the starch. At this time, the degree of gelatinization of starch must be at least 80% or more. If it is less than 80%, sufficient oil absorption cannot be obtained, and
It is not preferable because it may leave a rough feeling when used for foods. The ratio of water or warm water to starch or cereal flour containing 70% by weight or more of starch is 5 to 20 parts by weight of the former to the latter.
95 to 80 parts by weight is preferred. If the amount of water or hot water is too large or too small, the oil absorption amount will decrease.

Next, the starch thus obtained or the gelatinized product of cereal flour containing 70% by weight or more of starch is rapidly frozen. Freezing at temperatures below -30 ° C
Rapid complete freezing within 10 minutes is desirable. Further, in this freezing step, it is desirable that the α-form is thinly spread or formed into a fine linear shape in order to increase the freezing rate. As the freezing method, liquid nitrogen, a method of spraying or immersing a cryogenic gas such as liquid air, a method of immersing in a brine,
There are a method of contacting with a cooling metal plate and a glass plate, a method of using cooling air, a method of immersing in cooling ethanol, and the like, and all of these methods can be used.

Subsequently, the completely frozen starch or the gelatinized product of the flour containing 70% by weight or more of starch is dried. It is necessary to perform the drying treatment under the condition that the frozen ice crystals of the α-compound do not melt. For example,
A freeze vacuum drying method is a representative method. As another method, a method of dehydrating ethanol at a temperature of -1 ° C or lower is also effective. The above freeze-vacuum drying and frozen ethanol dehydration are performed until the water content of starch or starch containing 70% by weight or more of starch becomes 15% by weight or less. After this, it is also possible to further heat dry, vacuum dry, etc. to further reduce the water content.

The dried product thus obtained is pulverized by a pulverizer and sieved. The particle size of the powder after drying is not particularly limited,
It is desirable that the mesh size is about 20 to 100 mesh.

The highly oil-absorbing porous powder of the present invention can absorb and retain a larger amount of fats and oils as compared with the conventional ones. The term “oils and fats” as used herein includes all liquids and semi-solids fats and oils. Examples include soybean oil, corn oil, cottonseed oil, rapeseed oil, palm oil, coconut oil, fish oil, beef tallow, lard, whale oil, and the like, and also include hydrogenated products, transesterified products, and fractionated products of these oils and fats. .

In addition, all liquid- or semi-solid oil-soluble substances other than fats and oils can be similarly absorbed. What is an "oil-soluble substance"?
For example, oil-soluble surfactants, hydrocarbons, organic solvents and the like. Examples of the oil-soluble surfactant include monounsaturated fatty acid glycerin ester, monosaturated fatty acid glycerin ester having 8 or less carbon atoms, unsaturated fatty acid sorbitan ester, polyoxyethylene unsaturated fatty acid sorbitan ester and the like. Examples of the hydrocarbon include liquid paraffin and limonene, and examples of the organic solvent include propylene glycol, ethanol and methanol. It can also be applied to oil-soluble flavors and the like.

〔Example〕

Example 1 90 parts by weight of water was added to 10 parts by weight of corn starch,
While heating and stirring, a starch α-form having a degree of α-formation of 90% was produced. This was flash-freeze-dried for 10 minutes with dry ice-acetone (about -70 ° C) and then vacuum freeze-dried. Then, the vacuum dried product was pulverized using a pulverizer and then sieved to obtain a highly oil-absorbing porous powder having a 30-mesh size.

Example 2 90 parts by weight of water was added to 10 parts by weight of corn starch,
While heating and stirring, a starch α-form having a degree of α-formation of 100% was produced. This was snap frozen with dry ice-acetone (-70 ° C) and then vacuum freeze dried. Then, the vacuum dried product was pulverized using a pulverizer and then sieved to obtain a highly oil-absorbing porous powder having a 30-mesh size.

Example 3 98 parts by weight of water was added to 2 parts by weight of weak wheat flour having a starch content of 75%, and an α-form of wheat flour with a degree of gelatinization of 98% was obtained with heating and stirring. This was rapidly frozen with liquid nitrogen and then vacuum freeze-dried. Next, this was crushed using a crusher and sieved to obtain a highly oil-absorbing porous powder having 20 meshes.

Example 4 To 5 parts by weight of potato starch, 95 parts by weight of water was added, and the mixture was heated and stirred to obtain an α-form of potato starch having a degree of gelatinization of 85%. 100 g of this starch α-form was immersed in 1 kg of ethanol which had been previously cooled to −70 ° C. with dry ice, and rapidly frozen for 10 minutes. After rapid freezing, the temperature was raised to -5 ° C, stirred for 1 hour, and dehydrated. The alcohol was then filtered off and the ethanol was completely removed under vacuum. Finally, it was pulverized using a pulverizer and sieved to obtain a highly oil-absorbing porous powder having a 20-mesh size.

Example 5 95 parts by weight of water was added to 5 parts by weight of potato starch, and the mixture was heated and stirred to obtain an α-form of potato starch having a degree of α-formation of 100%. 100 g of this starch α-form was immersed in 1 kg of ethanol which had been previously cooled to −70 ° C. with dry ice, and rapidly frozen for 10 minutes. After quick freezing, raise the temperature to -5 ° C,
The mixture was stirred for 1 hour and dehydrated. The alcohol was then filtered off and the ethanol was completely removed under vacuum. Finally, it was pulverized using a pulverizer and sieved to obtain a highly oil-absorbing porous powder having a 20-mesh size.

Comparative Example 1 90 parts by weight of water was added to 10 parts by weight of corn starch,
While heating and stirring, a starch α-form having a degree of α-formation of 100% was produced. After slowly freezing this in a -20 ° C freezer for 30 minutes,
Vacuum freeze-drying, pulverization and sieving were carried out in the same manner as in Example 1 to obtain a powder of 30 mesh.

Comparative Example 2 90 parts by weight of water was added to 10 parts by weight of corn starch,
While heating and stirring, a starch α-form having a degree of α-formation of 30% was produced. Then, in the same manner as in Example 1, rapid freezing, vacuum freeze drying, pulverization and sieving were carried out to obtain a powder of 30 mesh.

The powder was found to have pores (10 to 20 μm) in only a part of the surface of the powder when observed by an electron microscope, and had a very small specific surface area.

Comparative Example 3 90 parts by weight of water was added to 10 parts by weight of corn starch,
While heating and stirring, a starch α-form having a degree of α-formation of 100% was produced. It was snap frozen in liquid nitrogen. It is then freeze-dried in a vacuum and then crushed using a crusher and sieved to 30
A powder that passed through the mesh was obtained.

Comparative Example 4 99 parts by weight of water was added to 1 part by weight of low-strength wheat flour having a starch content of 75%, and while heating and stirring, a wheat flour α-form having an α-degree of 98% was obtained. This was rapidly frozen in liquid nitrogen and then vacuum freeze-dried. Next, this was crushed using a crusher and sieved to obtain a powder of 20 mesh.

Test Example 1 The oil absorption capacity, the degree of alpha formation, the pore size, the specific surface area and the water solubility of the powders produced in Examples 1 to 5 and Comparative Examples 1 to 4 were measured. The measurement results are shown in Table 1. The measuring method used was as follows.

<Measurement of Oil Absorption Capacity> 1 g of the powder was placed in a 100 ml glass beaker, and rapeseed oil was added dropwise with a burette to stir and mix. The oil absorption capacity was defined as the rapeseed oil drop amount (ml) at the time when the separated oils and fats could not be absorbed completely and began to adhere to the beaker wall.

<Measurement of Degree of Alpha Formation> The glucoamylase method was used.

<Measurement of Pore Diameter> Using a scanning electron microscope (JEOL JSM-840), after vapor deposition of gold, observation was performed to measure the diameter of the hole.

<Measurement of specific surface area> The specific surface area was measured with an Oaur type specific surface area meter 2100D manufactured by Shimadzu Corporation using nitrogen gas.

<Water-Solubility> 1 g of powder was added to 100 ml of water, and after stirring, the amount of white particles insoluble in water was visually observed and judged.

[Effects of the Invention] The highly oil-absorbing porous powder of the present invention has excellent oil absorbency, food,
It has a property that it can absorb a large amount of hydrocarbons, oil-soluble surfactants, etc., as well as liquid or semi-solid oils and fats used in pharmaceuticals, cosmetics and the like.

Therefore, by using the product of the present invention, an oil-soluble liquid or semi-solid substance (oil and fat etc.) which has been conventionally inconvenient to handle,
It becomes possible to powder easily.

Claims (1)

[Claims] 1. The degree of gelatinization of starch in the powder is 80% or more,
The pore size of the powder is 1 to 15 μm, and the specific surface area is 3 to
In the method of obtaining a highly oil-absorbing porous powder which is 15 m ² / g,
Water or warm water is added to starch or cereal flour containing 70% by weight or more of starch to pregelatinize the starch so that the degree of pregelatinization becomes 80% or more. The method for producing a highly oil-absorbing porous powder, which comprises rapidly freezing at a temperature of, followed by drying and pulverizing.