阅读说明：本技术 一种醇水挤压制备v型冷水可溶淀粉的方法 (Method for preparing V-shaped cold water soluble starch by alcohol water extrusion ) 是由 周星 孟婷婷 金征宇 王韧 赵建伟 王金鹏 焦爱权 徐学明 于 2019-11-15 设计创作，主要内容包括：本发明申请公开了一种醇水挤压制备V型冷水可溶淀粉的方法,属于食品加工技术领域,该V型冷水可溶淀粉在冷水中能够快速溶胀成糊产生一定黏度,方便使用,且制备过程绿色高效,具体方法为：首先配制一定浓度的乙醇溶液、加入一定比例的淀粉配置成淀粉乳,随后将调配好的淀粉乳直接送入挤压机中进行挤压处理,制得条状挤出物,将条状挤出物压片、辊切制得薄片,并置于微波真空干燥箱中干燥,随后冷却并置于旋风式超微粉碎机中进行粉碎,即得V型冷水可溶淀粉。本发明解决了高浓度淀粉制备预糊化淀粉不易复水,再糊化后黏度过低的问题,制备过程能耗低且没有废水产生。(The invention discloses a method for preparing V-shaped cold water soluble starch by alcohol water extrusion, which belongs to the technical field of food processing, wherein the V-shaped cold water soluble starch can be quickly dissolved in cold water and can be swelled into paste to generate certain viscosity, the use is convenient, the preparation process is green and efficient, and the specific method comprises the following steps: firstly, preparing ethanol solution with a certain concentration, adding starch with a certain proportion to prepare starch milk, then directly sending the prepared starch milk into an extruder for extrusion treatment to prepare strip-shaped extrudate, tabletting the strip-shaped extrudate, cutting the strip-shaped extrudate into slices by a roller, placing the slices in a microwave vacuum drying oven for drying, then cooling and placing the slices in a cyclone type ultrafine pulverizer for pulverizing to obtain the V-shaped cold water soluble starch. The invention solves the problems that the pregelatinized starch prepared from high-concentration starch is not easy to rehydrate and has low viscosity after gelatinization, and the preparation process has low energy consumption and no wastewater.)

1. A method for preparing V-shaped cold water soluble starch by alcohol water extrusion is characterized by comprising the following steps:

(1) weighing a certain amount of starch, placing the starch in a container, adding an ethanol solution, and uniformly stirring to obtain starch milk;

(2) feeding the starch milk mixture obtained in the step (1) into an extruder for extrusion treatment to prepare a strip-shaped starch extrudate;

(3) tabletting the strip-shaped extrudate obtained in the step (2), and rolling and cutting to obtain slices with the side length of 2-6 cm;

(4) and (4) drying the slices obtained in the step (3) in a microwave vacuum drying oven, cooling, and crushing in an ultrafine crusher to obtain the cold water soluble starch.

2. The cold water soluble starch of claim 1, wherein the starch of step (1) comprises at least one of corn starch, tapioca starch, potato starch, wheat starch, rice starch.

3. The treatment method according to claim 1, wherein the ethanol solution in the step (1) has a mass fraction of 3-80%, the mass ratio of starch to the ethanol solution is 1:0.3-1.1, and the concentration of the obtained starch milk is 47-75%.

4. The process of claim 1, wherein the operating parameters of the extruder in step (2) are set as: the heating temperature of the premixing area is 50 ℃, the temperature of the pasting area is 70-120 ℃, the temperature of the forming area is fixed at 60 ℃, and the rotating speed of the extruder is 70-150 r/min; the starch extrudate has a diameter of 0.2-0.5cm and a length of 5-10 cm.

5. The V-shaped cold water soluble starch according to claim 1, wherein the drying temperature in the step (4) is 40-60 ℃, and the drying time is 5-30 min; the size of the screen of the ultrafine grinder is 0.3-1.0 mm.

Technical Field

The invention belongs to the technical field of food processing, and particularly relates to a method for preparing V-shaped cold water soluble starch by alcohol water extrusion.

Background

The starch is generally used after being heated and gelatinized, and the cold water soluble starch can avoid the trouble of heating and gelatinizing, thereby widening the application range of the starch. The cold water soluble starch is divided into two types of pregelatinized starch and granular V-shaped starch, and the current common method for industrially preparing the pregelatinized starch comprises the following steps: roller drying, spray drying, and extrusion. The concentration of the starch milk required by the roller drying method is generally controlled to be 20-40% (the water content is 60-80%), the starch milk needs to be uniformly distributed on a heated roller to form a thin layer and be gelatinized, when the starch milk is dried to the water content of about 5%, the starch milk is scraped by a scraper and then is crushed to obtain a finished product, and the process has high energy consumption and poor rehydration performance of the product; the concentration of the starch milk required by a spray drying method is generally controlled below 10%, the starch milk is firstly gelatinized and then is spray-dried, the energy consumption is very high, the concentration of the starch milk cannot exceed 40% by adopting a high-temperature and high-pressure spray technology, the viscosity of the prepared pre-gelatinized starch cold paste is improved, but the requirement on equipment is higher; the extrusion method has the advantages of low water content of the feed material, low energy consumption and low cost, but the prepared product almost has no cold paste viscosity, and the starch paste with certain viscosity can be obtained by proper heating. Granular type V starch is highly viscous in cold water and transparent in paste, and is generally prepared by two methods: high temperature and high pressure alcohol process, ethanol alkali process, etc. The reaction conditions required by the high-temperature high-pressure alcohol method are harsh, the concentration of the reacted starch is low, and a large amount of ethanol is required to be repeatedly washed after the reaction is finished; the ethanol-alkali method has mild reaction conditions, but in addition to low concentration of starch in the reaction and consumption of a large amount of organic reagents in the washing process, alkali needs to be added in the reaction process, acid needs to be used for neutralization after the reaction is completed, and a large amount of wastewater is generated, so that research and exploration of a production process of cold water soluble starch which is efficient, low in cost and environment-friendly are urgently needed.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for preparing V-shaped cold water soluble starch by alcohol water extrusion. The V-shaped granular cold water soluble starch can be formed by starch in an alcohol solution with a certain concentration at high temperature and high pressure, and a high-temperature and high-pressure environment can be generated in a cavity of an extruder in the extrusion process, so that the V-shaped cold water soluble starch is prepared by adopting an alcohol-water extrusion method under the condition of lower moisture content.

The invention has simple process, low cost, no need of a large amount of chemical reagents, low energy consumption, capability of adopting high-concentration starch for feeding, capability of extruding high-concentration starch milk containing certain ethanol, and capability of drying and crushing an extruded product to obtain the V-shaped cold water soluble starch with good cold water pasting property.

The technical scheme of the invention is as follows:

a method for preparing V-shaped cold water soluble starch by alcohol water extrusion, which comprises the following steps:

(1) weighing a certain amount of starch, placing the starch in a container, adding an ethanol solution, and uniformly stirring to obtain starch milk;

(2) feeding the starch milk mixture obtained in the step (1) into an extruder for extrusion treatment to prepare a strip-shaped starch extrudate;

(3) tabletting the strip-shaped extrudate obtained in the step (2), and rolling and cutting to obtain slices with the side length of 2-6 cm;

(4) and (4) drying the slices obtained in the step (3) in a microwave vacuum drying oven, cooling, and crushing in an ultrafine crusher to obtain the cold water soluble starch.

The starch in the step (1) comprises at least one of corn starch, cassava starch, potato starch, wheat starch and rice starch.

In the step (1), the mass fraction of the ethanol solution is 3% -80%, the mass ratio of starch to the ethanol solution is 1:0.3-1.1, and the concentration of the obtained starch milk is 47% -75%.

The operation parameters of the extruder in the step (2) are set as follows: the heating temperature of the premixing area is 50 ℃, the temperature of the pasting area is 70-120 ℃, the temperature of the forming area is fixed at 60 ℃, and the rotating speed of the extruder is 70-150 r/min; the starch extrudate has a diameter of 0.2-0.5cm and a length of 5-10 cm.

In the step (4), the drying temperature is 40-60 ℃, and the drying time is 5-30 min; the size of the screen of the ultrafine grinder is 0.3-1.0 mm.

The beneficial technical effects of the invention are as follows:

① the invention adopts high-concentration starch milk as raw material, greatly reduces energy consumption and production cost, ② the high temperature and high pressure environment in the extruder can make starch and ethanol form V-shaped crystal, achieves the crystal structure similar to V-shaped granular cold water soluble starch prepared by high temperature and high pressure alcohol method, has stronger diffraction peaks at 7 degrees, 13 degrees and 20 degrees in X-ray diffraction pattern (figure 1), ③ the cold paste of V-shaped cold water soluble starch prepared by extrusion is obviously improved compared with pregelatinized starch prepared by alcohol-free extrusion (figure 2), ④ the microwave vacuum drying technology adopted by the invention can generate expansion effect in the drying process, can increase the specific surface area and porosity of V-shaped starch, ⑤ the ultra-micro crushing technology can further increase the surface area and porosity of dried V-shaped starch, thereby the final product obtains good hydration ability and cold paste viscosity ⑥, the invention has no chemical reagent except ethanol, and the invention is environment-friendly.

Drawings

FIG. 1 is a graph showing the relative crystallinity and X-ray diffraction patterns of the V-shaped cold water soluble starch prepared in example 1 of the present invention, and pregelatinized starch prepared by alcohol-free extrusion, and raw starch (corn starch);

FIG. 2 is a schematic diagram showing the cold paste viscosities of the V-shaped cold water soluble starch prepared in example 1 of the present invention, the pregelatinized starch prepared by alcohol-free extrusion, and the raw starch (corn starch);

Detailed Description

The present invention will be described in detail with reference to examples.