阅读说明：本技术 一种大米淀粉的制备工艺 (Preparation process of rice starch ) 是由 李梦露 于 2018-06-20 设计创作，主要内容包括：本发明提供了淀粉制备技术领域内的一种大米淀粉的制备工艺,包括以下步骤,(1)大米粉的制备:将30g大米清洗后在150mL蒸馏水中浸泡18h,打浆后离心,干燥,过200目筛；(2)大米粉中直链淀粉含量的测定：采用直链淀粉分析试剂盒,根据Con A法进行测定；(3)大米淀粉的碱法制备；(4)大米淀粉颗粒破损率的测定：根据真菌α-淀粉酶对破损淀粉的敏感性,通过滴定其水解生成的还原糖的量来计算淀粉的破损率；(5)快速粘度测定仪测定大米淀粉的糊化特性；使用本发明制备出的大米淀粉糊化特性好。(The invention provides a preparation process of rice starch in the technical field of starch preparation, which comprises the following steps of (1) preparing rice flour, namely cleaning 30g of rice, soaking the rice in 150mL of distilled water for 18h, pulping, centrifuging, drying, and sieving by a 200-mesh sieve; (2) determination of amylose content in rice flour: determining by using an amylose analysis kit according to a Con A method; (3) preparing rice starch by an alkaline method; (4) and (3) determination of breakage rate of rice starch granules: calculating the breakage rate of the starch by titrating the amount of reducing sugar generated by hydrolysis of the fungal alpha-amylase according to the sensitivity of the fungal alpha-amylase to the broken starch; (5) a rapid viscosity tester is used for testing the gelatinization characteristic of the rice starch; the rice starch prepared by the invention has good gelatinization characteristic.)

1. A preparation process of rice starch is characterized by comprising the following steps:

(1) the rice flour is prepared by cleaning 30g rice, soaking in 150mL distilled water for 18h, pulping, centrifuging, drying, and sieving with 200 mesh sieve;

(2) determination of amylose content in rice flour: determining by using an amylose analysis kit according to a Con A method;

(3) preparing rice starch by an enzyme method: washing 30g of rice, soaking the rice in 150mL of distilled water for 18h, pulping, centrifuging, removing supernatant, uniformly mixing precipitate with 0.139% phosphoric acid buffer solution of Pronase protease (0.03 mol/L, pH 7.4) in a ratio of 1:5, placing the mixture on a shaking table for reaction for 48h, changing NaOH solution once at intervals of 24h, sieving the mixture through a 100-mesh sieve after the reaction is finished, centrifuging at room temperature (10000g, 10min), removing supernatant, washing the precipitate with water for 5 or 6 times until the pH value of supernatant is neutral, sieving the starch wet block through a 200-mesh sieve after freeze drying, and storing the obtained starch powder in a dryer for later use;

(4) and (3) determination of breakage rate of rice starch granules: calculating the breakage rate of the starch by titrating the amount of reducing sugar generated by hydrolysis of the fungal alpha-amylase according to the sensitivity of the fungal alpha-amylase to the broken starch;

(5) the quick viscosity tester is used for testing the gelatinization characteristic of the rice starch: 2.4g of starch is accurately weighed, 25mL of distilled water is added, and the mixture is mixed in a special cylindrical aluminum box of a width viscosity tester to prepare starch milk with the concentration of 8.8 percent.

2. The preparation process of rice starch according to claim 1, wherein the step (2) specifically comprises the following steps:

(201) accurately weighing 20mg of rice flour in a test tube with a plug, adding 1mL of DMSO, uniformly mixing in a vortex mixer, adding 2mL of 95% ethanol, uniformly oscillating, adding 4mL of ethanol, uniformly mixing, standing for 15min, 2000g, and centrifuging for 5 min;

(202) adding 0.2mL of DMSO into the precipitate, heating in a boiling water bath for 15min, adding 2mL of Con A, mixing uniformly, and diluting to 5mL (solution A) with Con A;

(203) taking 1.0mL of the solution A, putting the solution A into a 2.0mL centrifuge tube, adding 0.50mL of Con A solution, uniformly mixing for multiple times, and standing for 1 h;

(204) taking 0.5mL of the solution A, adding 4mL of 100mmol/L sodium acetate buffer solution with pH4.5, 0.1mL of amyloglucosidase and alpha-amylase solution, preserving the temperature for 10min at 40 ℃, taking 1.0mL, adding 4mL of GOPOD, preserving the temperature for 20min at 40 ℃, and then measuring the absorbance at 510 nm.

3. The preparation process of rice starch according to claim 1, wherein the step (4) specifically comprises the following steps:

(401) accurately weighing about 1g of starch in a conical flask, adding 0.05g of fungal alpha-amylase, adding 45mL of acetic acid buffer solution, keeping the temperature in a water bath at 30 ℃ for 15min, continuously stirring, adding 3mL of sulfuric acid solution and 2mL of sodium tungstate solution after the reaction is finished, uniformly mixing, keeping the mixture for 2min, filtering, and discarding the first 8-10 drops;

(402) immediately putting 5mL of filtrate in a test tube in the western region, adding 10mL of alkaline ferricyanate, mixing, immersing a measuring tube in a boiling water bath, timing for 20min, cooling the measuring tube by flowing tap water, completely transferring the reaction liquid into a conical flask, adding 1mL of starch potassium iodide solution, and fully and uniformly mixing;

(403) titrating with 0.1N thiosulfate until blue color disappears completely, and calculating the amount of reducing sugar;

(404) repeating the steps to make reagent blanks, wherein the calculation formula is as follows,

（1）；

wherein 1.64 is the coefficient of conversion of maltose to starch;

5 is the dilution factor of the sample;

(mg maltose/10 g starch) is obtained by looking up the table.

4. The process for preparing rice starch according to claim 1, wherein the determination conditions in the step (5) are specifically: keeping at 50 deg.C for 1min, increasing to 95 deg.C (3.75 min) at a speed of 12 deg.C/min, keeping at 95 deg.C below 2.5min, decreasing to 50 deg.C (3.75) min at 12 deg.C/min, and keeping at 50 deg.C for 1 min.

5. A process for preparing rice starch as claimed in claim 4, wherein in step (5), the stirrer speed is maintained at 160r/min during gelatinization.

Technical Field

The invention belongs to the technical field of starch preparation, and particularly relates to a preparation process of rice starch.

Background

The starch separation method is different according to different raw materials, the key step in the processing of the corn and wheat starch is the separation of gluten protein, and the processing of the cassava starch mainly adopts a screening method. The separation of rice starch is difficult compared to corn and wheat starch mainly because the starch in the rice endosperm is tightly bound to protein components and the tiny particles make the rice starch difficult to precipitate in water, increasing the difficulty of separation and purification. However, in order to fully utilize the excellent characteristics of small particle size and white color of rice starch granules, the starch must be efficiently separated from other components, among which separation from protein is the first to be achieved.

At present, the industrial production of rice starch mainly adopts the process of alkaline hydrolysis protein combined with centrifugal separation, but a large amount of salt and alkaline waste liquid can be introduced in the alkaline treatment process, so that the cost of wastewater treatment and discharge is increased.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to overcome the defects in the prior art and provide the preparation process of the rice starch, and a large amount of salt is not introduced, so that the burden of wastewater treatment is not increased.

The purpose of the invention is realized as follows: a preparation process of rice starch comprises (1) preparing rice flour by cleaning rice 30g, soaking in 150mL distilled water for 18h, pulping, centrifuging, drying, and sieving with 200 mesh sieve;

(2) determination of amylose content in rice flour: determining by using an amylose analysis kit according to a Con A method;

(3) the alkaline preparation method of the rice starch comprises the following steps: washing 30g of rice, soaking the rice in 150mL of distilled water for 18h, pulping, centrifuging, removing supernatant, uniformly mixing precipitate with 0.139% phosphoric acid buffer solution of Pronase protease (0.03 mol/L, pH 7.4) in a ratio of 1:5, placing the mixture on a shaking table for reaction for 48h, changing NaOH solution once at intervals of 24h, sieving the mixture through a 100-mesh sieve after the reaction is finished, centrifuging at room temperature (10000g, 10min), removing supernatant, washing the precipitate with water for 5 or 6 times until the pH value of supernatant is neutral, sieving the starch wet block through a 200-mesh sieve after freeze drying, and storing the obtained starch powder in a dryer for later use;

(4) and (3) determination of breakage rate of rice starch granules: calculating the breakage rate of the starch by titrating the amount of reducing sugar generated by hydrolysis of the fungal alpha-amylase according to the sensitivity of the fungal alpha-amylase to the broken starch;

(5) the quick viscosity tester is used for testing the gelatinization characteristic of the rice starch: 2.4g of starch is accurately weighed, 25mL of distilled water is added, and the mixture is mixed in a special cylindrical aluminum box of a width viscosity tester to prepare starch milk with the concentration of 8.8 percent.

In order to realize the determination of the amylose content in the rice flour, the step (2) specifically comprises the following steps:

(201) accurately weighing 20mg of rice flour in a test tube with a plug, adding 1mL of DMSO, uniformly mixing in a vortex mixer, adding 2mL of 95% ethanol, uniformly oscillating, adding 4mL of ethanol, uniformly mixing, standing for 15min, 2000g, and centrifuging for 5 min;

(202) adding 0.2mL of DMSO into the precipitate, heating in a boiling water bath for 15min, adding 2mL of Con A, mixing uniformly, and diluting to 5mL (solution A) with Con A;

(203) taking 1.0mL of the solution A, putting the solution A into a 2.0mL centrifuge tube, adding 0.50mL of Con A solution, uniformly mixing for multiple times, and standing for 1 h;

(204) taking 0.5mL of the solution A, adding 4mL of 100mmol/L sodium acetate buffer solution with pH4.5, 0.1mL of amyloglucosidase and alpha-amylase solution, preserving the temperature for 10min at 40 ℃, taking 1.0mL, adding 4mL of GOPOD, preserving the temperature for 20min at 40 ℃, and then measuring the absorbance at 510 nm.

In order to realize the determination of the breakage rate of the rice starch granules, the step (4) specifically comprises the following steps:

(401) accurately weighing about 1g of starch in a conical flask, adding 0.05g of fungal alpha-amylase, adding 45mL of acetic acid buffer solution, keeping the temperature in a water bath at 30 ℃ for 15min, continuously stirring, adding 3mL of sulfuric acid solution and 2mL of sodium tungstate solution after the reaction is finished, uniformly mixing, keeping the mixture for 2min, filtering, and discarding the first 8-10 drops;

(402) immediately putting 5mL of filtrate in a test tube in the western region, adding 10mL of alkaline ferricyanate, mixing, immersing a measuring tube in a boiling water bath, timing for 20min, cooling the measuring tube by flowing tap water, completely transferring the reaction liquid into a conical flask, adding 1mL of starch potassium iodide solution, and fully and uniformly mixing;

(403) titrating with 0.1N thiosulfate until blue color disappears completely, and calculating the amount of reducing sugar;

(404) repeating the steps to make reagent blanks, wherein the calculation formula is as follows,

（1）；

wherein 1.64 is the coefficient of conversion of maltose to starch;

5 is the dilution factor of the sample;

(mg maltose/10 g starch) is obtained by looking up the table.

As a further improvement of the present invention, the temperature is maintained at 50 ℃ for 1min, the temperature is raised to 95 ℃ (3.75 min) at a speed of 12 ℃/min, the temperature is maintained below 95 ℃ for 2.5min, the temperature is lowered to 50 ℃ (3.75) min at 12 ℃/min, and the temperature is maintained at 50 ℃ for 1 min.

As a further improvement of the invention, in the step (5), the speed of the stirrer is kept at 160r/min during the gelatinization.

Compared with the prior art, the invention has the technical effects that:

a method for rapidly evaluating the slow release performance of the fertilizer by a leaching method is provided, and the advantages and disadvantages of the slow release performance of the fertilizer can be evaluated by comparing slow release performance curves of different fertilizers; paraffin, release factors, surfactants and the like are selected as raw materials to prepare the envelope material which has the anti-caking performance and the slow-release performance.

Drawings

FIG. 1 is a graph showing the protein content and the total starch content in the natural rice and the prepared rice starch according to the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

A preparation process of rice starch comprises (1) preparing rice flour by cleaning rice 30g, soaking in 150mL distilled water for 18h, pulping, centrifuging, drying, and sieving with 200 mesh sieve;

(2) determination of amylose content in rice flour: determining by using an amylose analysis kit according to a Con A method;

(3) the alkaline preparation method of the rice starch comprises the following steps: washing 30g of rice, soaking the rice in 150mL of distilled water for 18h, pulping, centrifuging, removing supernatant, uniformly mixing precipitate with 0.139% phosphoric acid buffer solution of Pronase protease (0.03 mol/L, pH 7.4) in a ratio of 1:5, placing the mixture on a shaking table for reaction for 48h, changing NaOH solution once at intervals of 24h, sieving the mixture through a 100-mesh sieve after the reaction is finished, centrifuging at room temperature (10000g, 10min), removing supernatant, washing the precipitate with water for 5 or 6 times until the pH value of supernatant is neutral, sieving the starch wet block through a 200-mesh sieve after freeze drying, and storing the obtained starch powder in a dryer for later use;

(4) and (3) determination of breakage rate of rice starch granules: calculating the breakage rate of the starch by titrating the amount of reducing sugar generated by hydrolysis of the fungal alpha-amylase according to the sensitivity of the fungal alpha-amylase to the broken starch;

(5) the quick viscosity tester is used for testing the gelatinization characteristic of the rice starch: 2.4g of starch is accurately weighed, 25mL of distilled water is added, and the mixture is mixed in a special cylindrical aluminum box of a width viscosity tester to prepare starch milk with the concentration of 8.8 percent.

In order to realize the determination of the amylose content in the rice flour, the step (2) specifically comprises the following steps:

(201) accurately weighing 20mg of rice flour in a test tube with a plug, adding 1mL of DMSO, uniformly mixing in a vortex mixer, adding 2mL of 95% ethanol, uniformly oscillating, adding 4mL of ethanol, uniformly mixing, standing for 15min, 2000g, and centrifuging for 5 min;

(202) adding 0.2mL of DMSO into the precipitate, heating in a boiling water bath for 15min, adding 2mL of Con A, mixing uniformly, and diluting to 5mL (solution A) with Con A;

(203) taking 1.0mL of the solution A, putting the solution A into a 2.0mL centrifuge tube, adding 0.50mL of Con A solution, uniformly mixing for multiple times, and standing for 1 h;

(204) taking 0.5mL of the solution A, adding 4mL of 100mmol/L sodium acetate buffer solution with pH4.5, 0.1mL of amyloglucosidase and alpha-amylase solution, preserving the temperature for 10min at 40 ℃, taking 1.0mL, adding 4mL of GOPOD, preserving the temperature for 20min at 40 ℃, and then measuring the absorbance at 510 nm.

In order to realize the determination of the breakage rate of the rice starch granules, the step (4) specifically comprises the following steps:

(401) accurately weighing about 1g of starch in a conical flask, adding 0.05g of fungal alpha-amylase, adding 45mL of acetic acid buffer solution, keeping the temperature in a water bath at 30 ℃ for 15min, continuously stirring, adding 3mL of sulfuric acid solution and 2mL of sodium tungstate solution after the reaction is finished, uniformly mixing, keeping the mixture for 2min, filtering, and discarding the first 8-10 drops;

(402) immediately putting 5mL of filtrate in a test tube in the western region, adding 10mL of alkaline ferricyanate, mixing, immersing a measuring tube in a boiling water bath, timing for 20min, cooling the measuring tube by flowing tap water, completely transferring the reaction liquid into a conical flask, adding 1mL of starch potassium iodide solution, and fully and uniformly mixing;

(403) titrating with 0.1N thiosulfate until blue color disappears completely, and calculating the amount of reducing sugar;

(404) repeating the steps to make reagent blanks, wherein the calculation formula is as follows,

（1）；

wherein 1.64 is the coefficient of conversion of maltose to starch;

5 is the dilution factor of the sample;

(mg maltose/10 g starch) is obtained by looking up the table.

Keeping at 50 deg.C for 1min, increasing to 95 deg.C (3.75 min) at a speed of 12 deg.C/min, keeping at 95 deg.C below 2.5min, decreasing to 50 deg.C (3.75) min at 12 deg.C/min, and keeping at 50 deg.C for 1 min; during the gelatinization, the speed of the stirrer was kept at 160 r/min.

The amylose content in natural rice measured by the ConA method was: 20.8% of long-shaped rice (Xiong No. 5), 13.2% of polished round-grained rice (M202) and 1.7% of glutinous rice (Youguo No. 3), wherein the purity of starch is mainly prompted by two important indexes of protein content and total starch content, so that the protein content and the total starch content of the rice flour and the starch obtained by separation are respectively measured, and the protein content and the total starch content are shown in the attached figure 1.

The present invention is not limited to the above embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts based on the disclosed technical solutions, and these substitutions and modifications are all within the protection scope of the present invention.