阅读说明：本技术 一种低gi淀粉及其制备方法 (Low-GI starch and preparation method thereof ) 是由 刘开昌 龚魁杰 孙琳琳 郭玉秋 陈利容 高原 李晓月 王兴亚 张守梅 张娜娜 于 2020-12-09 设计创作，主要内容包括：本发明涉及淀粉制备技术领域,且公开了一种低GI淀粉及其制备方法,低GI淀粉原料为糯玉米和酶,制备方法包括以下步骤：S1.清洗；S2.粗磨；S3.挤压；S4.细磨；S5.初次酶解；S6.过滤；S7.离心；S8.二次酶解；S9.老化；S10.干燥。本发明以糯玉米为原料,采用绿色无污染、高效制备工艺,提高效率、降低生产成本,制备的淀粉直接用于下一步的酶解,酶解时间短,制得的低GI淀粉含量高。(The invention relates to the technical field of starch preparation, and discloses low GI starch and a preparation method thereof, wherein the low GI starch is prepared from waxy corn and enzyme, and the preparation method comprises the following steps: s1, cleaning; s2, coarse grinding; s3, extruding; s4, fine grinding; s5, primary enzymolysis; s6, filtering; s7, centrifuging; s8, carrying out secondary enzymolysis; s9, aging; and S10, drying. According to the invention, waxy corn is used as a raw material, a green pollution-free and efficient preparation process is adopted, the efficiency is improved, the production cost is reduced, the prepared starch is directly used for the next enzymolysis, the enzymolysis time is short, and the content of the prepared low-GI starch is high.)

1. A low GI starch is characterized in that the raw material is waxy corn.

2. The low GI starch according to claim 1, wherein the enzyme comprises an acid protease solution and isoamylase, and the activity of the acid protease solution is 500 to 2000U/g.

3. A method for preparing the low GI starch of claim 1, comprising the steps of:

s1, cleaning: weighing whole waxy corn, pretreating, soaking in clear water, washing, and vibrating to remove surface water;

s2, coarse grinding: transferring the soaked and cleaned waxy corns into a crusher for coarse crushing;

s3, extruding: carrying out extrusion treatment on the waxy corn powder obtained by coarse crushing;

s4, fine grinding: putting the extrusion product into a crusher for crushing;

s5, primary enzymolysis: soaking the crushed waxy corn powder in a soaking solution, adding 500-2000U/g of acid protease solution, and carrying out water bath at the temperature of 45-55 ℃ for 4-6 h;

s6, filtering: washing the oversize product with water for several times to remove residues such as embryo, seed coat, and gluten;

s7, centrifugation: centrifuging the filtered filtrate, and obtaining a precipitate as a starch sample;

s8, secondary enzymolysis: blending the starch sample in the S7 into 10-20% starch milk, adding isoamylase for enzymolysis for 1-6 h, immediately heating the solution to inactivate enzyme after the reaction is finished, then rapidly cooling to room temperature by using an ice bath, and adjusting the pH value to be neutral;

s9, aging: refrigerating and aging the starch subjected to secondary enzymolysis at 4 ℃ for 24-48 h;

s10, drying: and (3) drying the aged starch in a forced air drying oven, and crushing again to obtain the low GI starch.

4. The method of claim 3, wherein the pre-treatment of the waxy corn in S1 comprises removing moldy, broken and residual chaff.

5. The method of claim 3, wherein in S3, extrusion is stopped when the temperature is 90-110 ℃, the screw speed is 210-230 rpm, and the moisture content of the material is 16-20%.

6. The method of claim 3, wherein in S5, the pH of the soaking solution is 2.5-3.5.

7. The method of claim 3, wherein in S10, the temperature for drying in the forced air drying oven is 40-50 ℃.

Technical Field

The invention relates to the technical field of starch preparation, in particular to low GI starch and a preparation method thereof.

Background

The low GI starch comprises slowly digestible starch and resistant starch, wherein the slowly digestible starch refers to starch which can be completely digested and absorbed in the small intestine but has a slow absorption rate, and has special effects of slowly releasing glucose, facilitating blood sugar control and the like; resistant starch refers to starch that is not enzymatically hydrolyzed in the small intestine of a healthy human body and is not digested and absorbed by the healthy human body. The low GI starch can effectively control the energy supply speed, inhibit the rapid rise of blood sugar after meals, prevent the occurrence of blood sugar storm, promote the proliferation of beneficial flora in small intestines, and has more advantages than simple resistant starch.

At present, most modified starch such as resistant starch is prepared by taking original starch as a raw material and performing damp-heat treatment, microwave radiation, ultrasonic wave assistance, microbial fermentation, enzymolysis, acidolysis and other methods, and after the starch is dried, water needs to be added again, so that a large amount of water and electricity consumption and the like are caused, and a large amount of pollution is also generated. In addition, in the traditional process for producing the corn starch, soaking is a main process, so that the soaking process in China is generally time-consuming and low in production efficiency; and the addition of sodium sulfite causes environmental pollution. Therefore, the method for preparing the low-GI starch by adopting the one-step method breaks through the traditional preparation method of adopting starch and modified starch, and has important value for functional starch.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides the low GI starch and the preparation method thereof, which have the advantages of environmental friendliness, no pollution and high efficiency, and the prepared starch has a low GI value and is a low glycemic index product. The invention solves the problems that in the prior art, the functional starch is prepared by corn, the processes of repeated drying, dissolving and the like are needed for preparing the starch and then preparing the functional starch, the functional starch is directly prepared by a one-step method, the energy consumption is saved, and the environmental pollution is reduced.

(II) technical scheme

In order to realize the purpose of preparing the low GI starch, the invention provides the following technical scheme: a low GI starch and its preparation method, the raw materials are waxy corn kernel and enzyme.

Further, the enzyme comprises an acid protease solution and isoamylase, and the activity of the acid protease solution is 500-2000U/g.

A preparation method of low GI starch comprises the following steps:

s1, cleaning: weighing whole waxy corn, pretreating, soaking in clear water, washing, and vibrating to remove surface water;

s2, coarse grinding: transferring the soaked and cleaned waxy corns into a crusher for coarse crushing;

s3, extruding: carrying out extrusion treatment on the waxy corn powder obtained by coarse crushing;

s4, fine grinding: putting the extrusion product into a crusher for crushing;

s5, primary enzymolysis: soaking the crushed waxy corn powder in a soaking solution, adding 500-2000U/g of acid protease solution, and carrying out water bath at the temperature of 45-55 ℃ for 4-6 h;

s6, filtering: washing the oversize product with water for several times to remove residues such as embryo, seed coat, and gluten;

s7, centrifugation: centrifuging the filtered filtrate, and obtaining a precipitate as a starch sample;

s8, secondary enzymolysis: blending the starch sample in the S7 into 10-20% starch milk, adding isoamylase for enzymolysis for 1-6 h, immediately heating the solution to inactivate enzyme after the reaction is finished, then rapidly cooling to room temperature by using an ice bath, and adjusting the pH value to be neutral;

s9, aging: refrigerating and aging the starch subjected to secondary enzymolysis at 4 ℃ for 24-48 h;

s10, drying: and (3) drying the aged starch in a forced air drying oven, and crushing again to obtain the low GI starch.

Further, in S1, the pre-treatment of the waxy corn includes removing the moldy, cracked, residual chaff waxy corn.

Further, in S3, the extrusion temperature is 90-110 ℃, the screw rotation speed is 210-230 rpm, and the extrusion is stopped when the moisture content of the material is 16-20%.

Further, in S5, the pH value of the soaking solution is 2.5-3.5.

Further, in S10, the temperature for drying in the air drying oven is 40-50 ℃.

(III) advantageous effects

Compared with the prior art, the invention provides the low GI starch and the preparation method thereof, and the low GI starch has the following beneficial effects:

1. the invention adopts waxy corn as a raw material, waxy corn starch is all amylopectin, and the chain length is suitable for preparing low GI starch after the side chain is cut, so that the waxy corn starch is an excellent raw material for preparing the low GI starch.

2. The low GI starch prepared by the invention has GI of 42.8, has good function of inhibiting the fast rise of blood sugar after meals when being added into food,

3. the method for directly preparing the low GI starch avoids the traditional method for preparing modified starch or functional starch after preparing the starch, greatly saves energy consumption and reduces production cost.

4. The corn kernels are directly treated after being cleaned, so that the long-time soaking in the traditional starch preparation method is avoided, sodium sulfite and the like are added, the production cost is reduced, and the environmental pollution is reduced.

Drawings

FIG. 1 is a process flow diagram of a method for preparing low GI starch according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

Referring to fig. 1, the low-GI starch is prepared from waxy corn, an acid protease solution and isoamylase, wherein the activity of the acid protease solution is 500-800U/g, and the preparation method comprises the following steps:

s1, cleaning: weighing whole waxy corn, pretreating, soaking in clear water, washing, and vibrating to remove surface water;

s2, coarse grinding: transferring the soaked and cleaned waxy corns into a crusher for coarse crushing;

s3, extruding: extruding the waxy corn flour obtained by coarse crushing, wherein the extrusion temperature is 90 ℃, the screw rotation speed is 210rpm, and the extrusion is stopped when the moisture content of the material is 16%;

s4, fine grinding: putting the extrusion product into a crusher for crushing;

s5, primary enzymolysis: soaking the crushed waxy corn powder in a soaking solution, wherein the pH value of the soaking solution is 2.5, adding 500-800U/g of acid protease solution, and carrying out water bath at the temperature of 45 ℃ for 4 hours;

s6, filtering: washing the oversize product with water for several times to remove residues such as embryo, seed coat, and gluten;

s7, centrifugation: centrifuging the filtered filtrate, and obtaining a precipitate as a starch sample;

s8, secondary enzymolysis: blending the starch sample in the S7 into 10% starch milk, adding isoamylase for enzymolysis treatment for 2h, immediately heating the solution to inactivate enzyme after the reaction is finished, then rapidly cooling to room temperature by using an ice bath, and adjusting the pH value to be neutral;

s9, aging: refrigerating and aging the starch subjected to secondary enzymolysis at 4 ℃ for 24 hours;

s10, drying: and (3) drying the aged starch in a forced air drying oven at the temperature of 40 ℃, and crushing again to obtain the low GI starch.

Example two

Referring to fig. 1, the low-GI starch is prepared from waxy corn, an acid protease solution and isoamylase, wherein the activity of the acid protease solution is 800-1000U/g, and the preparation method comprises the following steps:

s1, cleaning: weighing whole waxy corn, pretreating, soaking in clear water, washing, and vibrating to remove surface water;

s2, coarse grinding: transferring the soaked and cleaned waxy corns into a crusher for coarse crushing;

s3, extruding: extruding the waxy corn flour obtained by coarse crushing, wherein the extrusion temperature is 100 ℃, the screw rotation speed is 215rpm, and the extrusion is stopped when the moisture content of the material is 18%;

s4, fine grinding: putting the extrusion product into a crusher for crushing;

s5, primary enzymolysis: soaking the crushed waxy corn powder in a soaking solution, wherein the pH value of the soaking solution is 2.8, adding an acid protease solution of 800-1000U/g, and carrying out water bath at the temperature of 48 ℃ for 4.5 hours;

s6, filtering: washing the oversize product with water for several times to remove residues such as embryo, seed coat, and gluten;

s7, centrifugation: centrifuging the filtered filtrate, and obtaining a precipitate as a starch sample;

s8, secondary enzymolysis: blending the starch sample in the S7 into 12% starch milk, adding isoamylase for enzymolysis treatment for 3h, immediately heating the solution to inactivate enzyme after the reaction is finished, then rapidly cooling to room temperature by using an ice bath, and adjusting the pH value to be neutral;

s9, aging: refrigerating and aging the starch subjected to secondary enzymolysis at 4 ℃ for 26 h;

s10, drying: and (3) drying the aged starch in a forced air drying oven at the temperature of 42 ℃, and crushing again to obtain the low GI starch.

EXAMPLE III

Referring to fig. 1, the low-GI starch is prepared from waxy corn, an acid protease solution and isoamylase, wherein the activity of the acid protease solution is 1000-1300U/g, and the preparation method comprises the following steps:

s1, cleaning: weighing whole waxy corn, pretreating, soaking in clear water, washing, and vibrating to remove surface water;

s2, coarse grinding: transferring the soaked and cleaned waxy corns into a crusher for coarse crushing;

s3, extruding: extruding the waxy corn flour obtained by coarse crushing, wherein the extrusion temperature is 100 ℃, the screw rotating speed is 220rpm, and the extrusion is stopped when the moisture content of the material is 18%;

s4, fine grinding: putting the extrusion product into a crusher for crushing;

s5, primary enzymolysis: soaking the crushed waxy corn powder in a soaking solution, wherein the pH value of the soaking solution is 3, adding 1000-1300U/g of acid protease solution, and carrying out water bath at the temperature of 50 ℃ for 5 hours;

s6, filtering: washing the oversize product with water for several times to remove residues such as embryo, seed coat, and gluten;

s7, centrifugation: centrifuging the filtered filtrate, and obtaining a precipitate as a starch sample;

s8, secondary enzymolysis: blending the starch sample in the S7 into 15% starch milk, adding isoamylase for enzymolysis for 4 hours, immediately heating the solution to inactivate enzyme after the reaction is finished, then rapidly cooling to room temperature by using an ice bath, and adjusting the pH value to be neutral;

s9, aging: refrigerating and aging the starch subjected to secondary enzymolysis at 4 ℃ for 30 h;

s10, drying: and (3) drying the aged starch in a forced air drying oven at the temperature of 48 ℃, and crushing again to obtain the low GI starch.

Example four

Referring to fig. 1, the low-GI starch is prepared from waxy corn, an acid protease solution and isoamylase, wherein the activity of the acid protease solution is 1500-2000U/g, and the preparation method comprises the following steps:

s1, cleaning: weighing whole waxy corn, pretreating, soaking in clear water, washing, and vibrating to remove surface water;

s2, coarse grinding: transferring the soaked and cleaned waxy corns into a crusher for coarse crushing;

s3, extruding: extruding the waxy corn flour obtained by coarse crushing, wherein the extrusion temperature is 110 ℃, the screw rotation speed is 230rpm, and the extrusion is stopped when the moisture content of the material is 20%;

s4, fine grinding: putting the extrusion product into a crusher for crushing;

s5, primary enzymolysis: soaking the crushed waxy corn powder in a soaking solution, wherein the pH value of the soaking solution is 3.5, adding 1500-2000U/g acid protease solution, and carrying out water bath at the temperature of 55 ℃ for 6 h;

s6, filtering: washing the oversize product with water for several times to remove residues such as embryo, seed coat, and gluten;

s7, centrifugation: centrifuging the filtered filtrate, and obtaining a precipitate as a starch sample;

s8, secondary enzymolysis: blending the starch sample in the S7 into 20% starch milk, adding isoamylase for enzymolysis treatment for 6h, immediately heating the solution to inactivate enzyme after the reaction is finished, then rapidly cooling to room temperature by using an ice bath, and adjusting the pH value to be neutral;

s9, aging: refrigerating and aging the starch subjected to secondary enzymolysis at 4 ℃ for 48 h;

s10, drying: and (3) drying the aged starch in a forced air drying oven at the temperature of 50 ℃, and crushing again to obtain the low GI starch.

Glycemic index: the increase in area under the curve of the blood glucose response over time after a target amount of available carbohydrate food was consumed, divided by the corresponding increase after a reference food (glucose) containing an equal amount of available carbohydrate, expressed as a percentage, and GI is a physiological indicator reflecting the effect of food on blood glucose.

The four groups of examples and the control group were tested by purchasing a commercially available low GI starch as the control group according to the GI measurement method using international organization for standardization (ISO) specifications, and the following table was obtained:

	example one	Example two	EXAMPLE III	Example four	Control group
						GI value	42.25	43.46	41.72	42.13	52

As is apparent from the table above, the GI value content of the four groups of examples is obviously lower than the measured value of the low GI starch in the market, and the starch corresponding to the third example has the lowest GI value content, is more suitable for eating, can effectively control the energy supply speed, inhibit the rapid rise of the blood sugar after meal and prevent the occurrence of blood sugar storm.

The low GI starches of the four groups of examples and the control group were processed into flour and steamed bread for tasting, respectively, to obtain the following table:

according to the table, the wheaten food made of the low GI starch is obviously superior to the existing low GI starch in the market in taste and elasticity.

It is to be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.