阅读说明：本技术 一种限制性糊化改性糯米粉的制备方法 (Preparation method of limiting gelatinized modified glutinous rice flour ) 是由 庄坤 张晨 丁文平 王月慧 王国珍 陈曦 于 2019-12-19 设计创作，主要内容包括：本发明公开一种限制性糊化改性糯米粉的制备方法,包括以下步骤：将生糯米粉加水制成糯米粉乳液；将所述糯米粉乳液先在8～12℃下保温处理1.5～2.5h,再在3～5℃下保温处理2.5～3.5h,然后在40～60℃下保温处理8～24h,得限制性糊化糯米粉浆料；对所述限制性糊化糯米粉浆料进行压滤并收集滤饼；对所述滤饼依次进行预速冻、升华干燥和脱水干燥,制得限制性糊化糯米粉；将所述限制性糊化糯米粉与生糯米粉混合,制得限制性糊化改性糯米粉。本发明通过糯米粉的限制性糊化处理,能够达到提升糯米粉吸水性能的作用。(The invention discloses a preparation method of limiting gelatinized modified glutinous rice flour, which comprises the following steps: adding water into raw glutinous rice flour to prepare glutinous rice flour emulsion; carrying out heat preservation treatment on the glutinous rice flour emulsion at 8-12 ℃ for 1.5-2.5 h, then carrying out heat preservation treatment at 3-5 ℃ for 2.5-3.5 h, and then carrying out heat preservation treatment at 40-60 ℃ for 8-24 h to obtain limiting gelatinized glutinous rice flour slurry; filter-pressing the limiting gelatinized glutinous rice flour slurry and collecting a filter cake; sequentially carrying out pre-quick-freezing, sublimation drying and dehydration drying on the filter cake to prepare the limiting gelatinized glutinous rice flour; and mixing the limiting gelatinized glutinous rice flour with raw glutinous rice flour to prepare the limiting gelatinized modified glutinous rice flour. According to the invention, the effect of improving the water absorption performance of the glutinous rice flour can be achieved through the restrictive gelatinization treatment of the glutinous rice flour.)

1. The preparation method of the limiting gelatinized modified glutinous rice flour is characterized by comprising the following steps of:

adding water into raw glutinous rice flour to prepare glutinous rice flour emulsion;

carrying out heat preservation treatment on the glutinous rice flour emulsion at 8-12 ℃ for 1.5-2.5 h, then carrying out heat preservation treatment at 3-5 ℃ for 2.5-3.5 h, and then carrying out heat preservation treatment at 40-60 ℃ for 8-24 h to obtain limiting gelatinized glutinous rice flour slurry;

filter-pressing the limiting gelatinized glutinous rice flour slurry and collecting a filter cake;

sequentially carrying out pre-quick-freezing, sublimation drying and dehydration drying on the filter cake to prepare the limiting gelatinized glutinous rice flour;

and mixing the limiting gelatinized glutinous rice flour with raw glutinous rice flour to prepare the limiting gelatinized modified glutinous rice flour.

2. The method of preparing a restricted gelatinized modified glutinous rice flour as set forth in claim 1, wherein the step of adding water to the raw glutinous rice flour to prepare the glutinous rice flour emulsion comprises:

carrying out water spraying and constantly stirring on the glutinous rice flour through a spraying device, and adjusting the water content of the glutinous rice flour to 50-70% to prepare glutinous rice flour emulsion.

3. The method for preparing the restricted gelatinized modified glutinous rice flour according to claim 1, wherein the step of subjecting the glutinous rice flour emulsion to heat preservation treatment at 8 to 12 ℃ for 1.5 to 2.5 hours, further to heat preservation treatment at 3 to 5 ℃ for 2.5 to 3.5 hours, and then to heat preservation treatment at 40 to 60 ℃ for 8 to 24 hours to obtain a restricted gelatinized glutinous rice flour slurry comprises:

and (3) carrying out heat preservation treatment on the glutinous rice flour emulsion at the temperature of 8-12 ℃ for 1.5-2.5 h, then cooling to the temperature of 3-5 ℃ at the speed of 0.2-1.0 ℃/min, carrying out heat preservation treatment for 2.5-3.5 h, and then transferring to the temperature of 40-60 ℃ for heat preservation treatment for 8-24 h to obtain the limiting gelatinized glutinous rice flour slurry.

4. The method according to claim 1, wherein the step of pre-freezing, sublimation-drying, and dehydration-drying the cake to obtain the restricted gelatinized glutinous rice flour comprises the steps of:

and cooling the filter cake to-8 to-12 ℃ at the speed of 4 to 5 ℃/min, preserving heat for 1.5 to 2.5 hours, cooling to-17 to-23 ℃ at the speed of 3 to 4 ℃/min, preserving heat for 0.5 to 1.5 hours, cooling to-25 to-35 ℃ at the speed of 1 to 2 ℃/min, and preserving heat for 2.5 to 3.5 hours.

5. The method according to claim 1, wherein the step of subjecting the cake to pre-freezing, sublimation drying and dehydration drying in this order to obtain the restricted gelatinized glutinous rice flour comprises:

and treating the filter cake for 2-6 h under the environment of vacuum degree of 5-15 Pa and temperature of-50 to-60 ℃.

6. The method according to claim 1, wherein the step of subjecting the cake to pre-freezing, sublimation drying and dehydration drying in this order to obtain the restricted gelatinized glutinous rice flour comprises:

the filter cake is firstly treated for 20-40 min under the environment with the vacuum degree of 5-10 Pa and the temperature of-8-12 ℃, then treated for 1-2 h under the environment with the vacuum degree of 7-10 Pa and the temperature of-2 ℃, and then treated for 1-5 h under the environment with the vacuum degree of 1-5 Pa and the temperature of 25-30 ℃.

7. The preparation method of the gelatinized modified glutinous rice flour according to claim 6, wherein the cake is treated in an environment of a vacuum degree of 5 to 10Pa and a temperature of-8 to-12 ℃ for 20 to 40min, then in an environment of a vacuum degree of 7 to 10Pa and a temperature of-2 to 2 ℃ for 1 to 2 hours, and then in an environment of a vacuum degree of 1 to 5Pa and a temperature of 25 to 30 ℃ for 1 to 5 hours, and the method comprises the steps of:

heating the filter cake from-50 to-60 ℃ to-8 to-12 ℃ at the speed of 10 to 15 ℃/h under the vacuum degree of 5 to 10Pa, and preserving the heat for 20 to 40 min; reducing the vacuum degree to 7-10 Pa, heating to-2 ℃ at the speed of 10-15 ℃/h, and preserving the heat for 1-2 h; then reducing the vacuum degree to 1-5 Pa, raising the temperature to 25-30 ℃ at the rate of 20-25 ℃, and preserving the temperature for 1-5 h.

8. The method of preparing a restricted gelatinized modified glutinous rice flour according to claim 1, wherein the step of mixing the restricted gelatinized modified glutinous rice flour with raw glutinous rice flour to obtain a restricted gelatinized modified glutinous rice flour comprises:

the mass fraction of the limiting gelatinized glutinous rice flour in the limiting gelatinized modified glutinous rice flour is 20-100%.

Technical Field

The invention relates to the technical field of food processing, in particular to the technical field of glutinous rice flour processing, and specifically relates to a preparation method of restricted gelatinized modified glutinous rice flour.

Background

The starch in the glutinous rice flour is mainly amylopectin and has the characteristics of high freeze-thaw stability and low aging degree, so the raw material of the quick-frozen food in the market at present is mainly glutinous rice flour. However, due to the defects of the nature of the glutinous rice, the ungelatinized glutinous rice flour has poor cohesiveness, water absorption and water retention, cannot form gluten like flour, has excessive water addition and much free water, and has poor water absorption and water retention due to water loss and migration in the freezing process, so that the application of the existing glutinous rice flour in quick-frozen foods is seriously influenced, and the quick-frozen glue puddings produced from the glutinous rice flour are easy to crack after being frozen and stored. Particularly, in the quick-freezing process of the quick-frozen glue pudding, the outer skin of the quick-frozen glue pudding is frozen and solidified firstly, a large amount of moisture in the stuffing is not frozen, the moisture in the stuffing is frozen and expanded to generate internal pressure along with the reduction of temperature, so that the frozen outer skin of the outer layer is cracked, in the freezing process, the temperature of the glue pudding skin is continuously reduced due to the heat exchange, the water retention capacity is continuously reduced, the moisture is continuously sublimated to cause the water loss, and finally the glue pudding is cracked. In addition, because of the high glycemic index brought by the traditional glutinous rice flour, the traditional glutinous rice flour is easy to cause obesity, does not accord with the popular consumption trend of the current low-sugar diet, and influences and restricts the development of the frozen food processing industry taking the glutinous rice flour as the raw material.

Aiming at the problems, the defects of the glutinous rice flour are compensated by adopting the following three ways: (1) the problem of poor water absorption and water retention of the ungelatinized glutinous rice flour is solved by adding the pregelatinized flour and the coarse cereal flour from an external source. However, because the glutinous rice flour is added with different sources of flour, the apparent property difference is large, the excessive addition amount easily causes uneven distribution of pre-gelatinized flour in mixed flour, the produced frozen food wrappers have poor uniformity, and the taste of the original glutinous rice flour is changed subversively: when the addition amount is too small, the frozen dough skin still has the problem of local cracking. (2) The novel technical means is adopted to improve the flour milling process, and the treatments such as water milling, superfine grinding and the like are introduced, so that the fineness and the uniformity of the glutinous rice flour are improved as much as possible, and the water absorption and retention capacity of the glutinous rice flour is improved. However, the glutinous rice flour prepared by these techniques has extremely high quality and cost, and low efficiency, and is not suitable for industrial production. (3) The performance of the glutinous rice flour is improved by adding food additives into food, however, the improvement method relates to the problems of food safety and the like, and does not meet the current requirements on green and healthy food. Therefore, a safer, scientific, efficient and low-cost solution is widely expected by enterprises and consumers.

Disclosure of Invention

The invention mainly aims to provide a preparation method of limiting gelatinized modified glutinous rice flour, aiming at improving the water absorption performance of the glutinous rice flour.

In order to achieve the purpose, the invention provides a preparation method of limiting gelatinized modified glutinous rice flour, which comprises the following steps:

adding water into raw glutinous rice flour to prepare glutinous rice flour emulsion;

carrying out heat preservation treatment on the glutinous rice flour emulsion at 8-12 ℃ for 1.5-2.5 h, then carrying out heat preservation treatment at 3-5 ℃ for 2.5-3.5 h, and then carrying out heat preservation treatment at 40-60 ℃ for 8-24 h to obtain limiting gelatinized glutinous rice flour slurry;

filter-pressing the limiting gelatinized glutinous rice flour slurry and collecting a filter cake;

sequentially carrying out pre-quick-freezing, sublimation drying and dehydration drying on the filter cake to prepare the limiting gelatinized glutinous rice flour;

and mixing the limiting gelatinized glutinous rice flour with raw glutinous rice flour to prepare the limiting gelatinized modified glutinous rice flour.

Optionally, the step of adding water to the raw glutinous rice flour to make the glutinous rice flour emulsion comprises:

carrying out water spraying and constantly stirring on the glutinous rice flour through a spraying device, and adjusting the water content of the glutinous rice flour to 50-70% to prepare glutinous rice flour emulsion.

Optionally, the step of performing heat preservation treatment on the glutinous rice flour emulsion at 8-12 ℃ for 1.5-2.5 h, then performing heat preservation treatment at 3-5 ℃ for 2.5-3.5 h, and then performing heat preservation treatment at 40-60 ℃ for 8-24 h to obtain the limiting gelatinized glutinous rice flour slurry comprises the following steps:

and (3) carrying out heat preservation treatment on the glutinous rice flour emulsion at the temperature of 8-12 ℃ for 1.5-2.5 h, then cooling to the temperature of 3-5 ℃ at the speed of 0.2-1.0 ℃/min, carrying out heat preservation treatment for 2.5-3.5 h, and then transferring to the temperature of 40-60 ℃ for heat preservation treatment for 8-24 h to obtain the limiting gelatinized glutinous rice flour slurry.

Optionally, in the step of sequentially performing pre-freezing, sublimation drying and dehydration drying on the filter cake to obtain the limiting gelatinized glutinous rice flour, the pre-freezing step includes:

and cooling the filter cake to-8 to-12 ℃ at the speed of 4 to 5 ℃/min, preserving heat for 1.5 to 2.5 hours, cooling to-17 to-23 ℃ at the speed of 3 to 4 ℃/min, preserving heat for 0.5 to 1.5 hours, cooling to-25 to-35 ℃ at the speed of 1 to 2 ℃/min, and preserving heat for 2.5 to 3.5 hours.

Optionally, in the step of sequentially performing pre-freezing, sublimation drying and dehydration drying on the filter cake to obtain the limiting gelatinized glutinous rice flour, the sublimation drying step includes:

and treating the filter cake for 2-6 h under the environment of vacuum degree of 5-15 Pa and temperature of-50 to-60 ℃.

Optionally, in the step of sequentially performing pre-freezing, sublimation drying and dehydration drying on the filter cake to obtain the limiting gelatinized glutinous rice flour, the dehydration drying step includes:

the filter cake is firstly treated for 20-40 min under the environment with the vacuum degree of 5-10 Pa and the temperature of-8-12 ℃, then treated for 1-2 h under the environment with the vacuum degree of 7-10 Pa and the temperature of-2 ℃, and then treated for 1-5 h under the environment with the vacuum degree of 1-5 Pa and the temperature of 25-30 ℃.

Optionally, the filter cake is firstly treated for 20-40 min in an environment with a vacuum degree of 5-10 Pa and a temperature of-8 to-12 ℃, then treated for 1-2 h in an environment with a vacuum degree of 7-10 Pa and a temperature of-2 to 2 ℃, and then treated for 1-5 h in an environment with a vacuum degree of 1-5 Pa and a temperature of 25-30 ℃, and the method comprises the following steps:

heating the filter cake from-50 to-60 ℃ to-8 to-12 ℃ at the speed of 10 to 15 ℃/h under the vacuum degree of 5 to 10Pa, and preserving the heat for 20 to 40 min; reducing the vacuum degree to 7-10 Pa, heating to-2 ℃ at the speed of 10-15 ℃/h, and preserving the heat for 1-2 h; then reducing the vacuum degree to 1-5 Pa, raising the temperature to 25-30 ℃ at the rate of 20-25 ℃, and preserving the temperature for 1-5 h.

Optionally, the step of mixing the limiting gelatinized glutinous rice flour with raw glutinous rice flour to obtain the limiting gelatinized modified glutinous rice flour comprises:

the mass fraction of the limiting gelatinized glutinous rice flour in the limiting gelatinized modified glutinous rice flour is 20-100%.

According to the technical scheme provided by the invention, the limiting gelatinization treatment is firstly carried out on the raw glutinous rice flour, then the limiting gelatinization glutinous rice flour is prepared by freeze drying, the limiting gelatinization glutinous rice flour is backfilled into the raw glutinous rice flour to prepare the limiting gelatinization modified glutinous rice flour, and the effect of improving the water absorption performance of the glutinous rice flour can be achieved by the limiting gelatinization treatment of the glutinous rice flour, which is because: under the combined action of water and heat energy, the molecular mobility of the amorphous region of the starch is improved, so that the radial and tangential swinging of molecular chains in the crystalline region and the amorphous region is enhanced, and favorable conditions are created for rearrangement; reversible expansion of starch grains occurs, the reversible expansion of the amorphous area applies pressure to the crystalline area of the amylopectin to enable the crystalline area to generate certain fluidity, the excessive moisture and the temperature rise in a certain range can promote the fluidity of the glucan chain to be enhanced, the generation of the popularity enables the double helix structure to realize limited movement, thereby completing the transformation from nematic phase to smectic phase, and the orderliness of the double helix structure is improved no matter in the lamellar structure of the amorphous area or in the side chain double helix of the amylopectin; in the limiting gelatinization process of the glutinous rice flour, the starch grains reach the melting point temperature, wherein the microcrystalline bundles are disintegrated, hydrogen bonds in molecules are partially broken, the structure of the starch grains becomes looser, water molecules can enter more easily, the water absorption rate of the glutinous rice flour can be effectively increased, and the cracking rate and the water loss of finished frozen dough sheets are reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other related drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic flow chart of one embodiment of the method for preparing the gelatinized modified glutinous rice flour according to the present invention;

FIG. 2 is an SEM image of raw glutinous rice flour;

FIG. 3 is an SEM photograph of the limiting gelatinized modified glutinous rice flour obtained in example 1;

FIG. 4 is a whiteness change curve of the gelatinized and modified glutinous rice flour with different backfilling ratios of the gelatinized starch with different limitations;

FIG. 5 is a graph of the digestion characteristics of the gelatinized modified glutinous rice flour with different backfill ratios of the gelatinized starch;

FIG. 6 is a freezing curve of the quick-frozen rice dumpling prepared from the modified glutinous rice flour.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially. In addition, the meaning of "and/or" appearing throughout includes three juxtapositions, exemplified by "A and/or B" including either A or B or both A and B. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention. 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.

When the existing glutinous rice flour is used for making quick-frozen food, the glutinous rice starch is not gelatinized, so that the glutinous rice flour is poor in cohesiveness, water absorption and water retention, and cannot form gluten like flour, the free water is much due to the water addition, and the problems of skin wrinkles, fine lines and the like of the quick-frozen food are caused due to the loss and the migration of water in the freezing process. And the raw glutinous rice flour is consumed slowly, so that the quick-freezing effect is poor. In addition, because the glutinous rice flour produced by the defects of the traditional glutinous rice flour production process is the glutinous rice flour, the quality, the particle uniformity and the processing applicability of the produced glutinous rice flour are greatly different, and the problem that the glutinous rice flour is easy to become fat due to high amylopectin content exists.

According to the research of the invention, the research discovers that the water absorption, water retention and dispersibility of the glutinous rice flour can be effectively improved by carrying out the restrictive gelatinization treatment on the glutinous rice flour, and the freezing rate of the glutinous rice flour is effectively accelerated. Therefore, the limiting gelatinization of the glutinous rice flour can effectively improve the quick-freezing effect of the glutinous rice flour, can avoid cracking of the product in the quick-freezing process, and improves the yield, thereby reducing the production cost.

The invention can effectively solve the problem of uneven product quality by adopting a technology of restricting new gelatinization.

The patent increases the content of resistant starch in the glutinous rice flour through restrictive gelatinization and reduces the digestibility of the glutinous rice flour, thereby more conforming to the popular taste of low sugar and low fat in the modern times.

In view of the above, the preparation method of the limitation gelatinized modified glutinous rice flour provided by the invention has the advantages that the water absorption, water retention and dispersibility of glutinous rice are effectively improved by performing the limitation gelatinization treatment on the glutinous rice flour, the freezing rate of the glutinous rice flour is effectively accelerated, the problem that a quick-frozen product made of the glutinous rice flour cracks in the quick-freezing process can be avoided, the yield is improved, and the production cost is favorably reduced; the grain size distribution of the prepared glutinous rice flour is uniform, the content of resistant starch in the glutinous rice flour is increased, the digestibility of the glutinous rice flour is reduced, and the glutinous rice flour is more in line with the popular taste of low sugar and low fat in the modern times. Fig. 1 shows an embodiment of a method for preparing a limiting gelatinized modified glutinous rice flour according to the present invention, please refer to fig. 1, in this embodiment, the method for preparing the limiting gelatinized modified glutinous rice flour includes the following steps:

step S10, adding water into raw glutinous rice flour to prepare glutinous rice flour emulsion;

adding water into raw glutinous rice flour, stirring until the raw glutinous rice flour is fully mixed to obtain glutinous rice flour emulsion, preferably preparing the glutinous rice flour emulsion in a spraying mode for improving the mixing efficiency of the glutinous rice flour and the water, wherein the method comprises the following steps: carry out moisture through spray set to the glutinous rice flour and constantly stir, adjust to the water content of glutinous rice flour and be 50 ~ 70%, prepare the glutinous rice flour emulsion, this process can be regarded as the toughening to the glutinous rice flour.

Step S20, firstly, carrying out heat preservation treatment on the glutinous rice flour emulsion at the temperature of 8-12 ℃ for 1.5-2.5 h, then carrying out heat preservation treatment at the temperature of 3-5 ℃ for 2.5-3.5 h, and then carrying out heat preservation treatment at the temperature of 40-60 ℃ for 8-24 h to obtain limiting gelatinized glutinous rice flour slurry;

after the glutinous rice flour emulsion is obtained through toughening, low-temperature balance is firstly carried out to ensure that water fully infiltrates the glutinous rice flour, hydrogen bonds are formed among starch, then the moist heat treatment is carried out above the glass transition temperature of the glutinous rice flour and below the gelatinization temperature of the glutinous rice flour, and the process and the toughening process can be regarded as limiting gelatinization treatment on the glutinous rice flour. In this embodiment, the specific implementation method of step S20 is as follows: and (3) carrying out heat preservation treatment on the glutinous rice flour emulsion at the temperature of 8-12 ℃ for 1.5-2.5 h, then cooling to the temperature of 3-5 ℃ at the speed of 0.2-1.0 ℃/min, carrying out heat preservation treatment for 2.5-3.5 h, and then transferring to the temperature of 40-60 ℃ for heat preservation treatment for 8-24 h to obtain the limiting gelatinized glutinous rice flour slurry.

Step S30, performing pressure filtration on the limiting gelatinized glutinous rice flour slurry and collecting a filter cake;

the resulting limiting gelatinized glutinous rice flour slurry was subjected to pressure filtration through a plate and frame filter press to remove most of the water therefrom and collect the filter cake.

Step S40, sequentially carrying out pre-quick-freezing, sublimation drying and dehydration drying on the filter cake to prepare limiting gelatinized glutinous rice flour;

the restrictive pregelatinized starch slurry is subjected to filter pressing to remove most of water, and then is subjected to freeze drying, so that the original characteristics, nutritional ingredients, active ingredients, trace elements and the like of the glutinous rice flour can be retained to the maximum extent. In this embodiment, the freeze-drying process sequentially includes pre-freezing, sublimation drying, and dehydration drying, wherein the pre-freezing step includes: and cooling the filter cake to-8 to-12 ℃ at the speed of 4 to 5 ℃/min, preserving heat for 1.5 to 2.5 hours, cooling to-17 to-23 ℃ at the speed of 3 to 4 ℃/min, preserving heat for 0.5 to 1.5 hours, cooling to-25 to-35 ℃ at the speed of 1 to 2 ℃/min, and preserving heat for 2.5 to 3.5 hours.

The step of sublimation drying comprises: and treating the filter cake for 2-6 h under the environment of vacuum degree of 5-15 Pa and temperature of-50 to-60 ℃.

The step of dehydrating and drying comprises: the filter cake is firstly treated for 20-40 min under the environment with the vacuum degree of 5-10 Pa and the temperature of-8-12 ℃, then treated for 1-2 h under the environment with the vacuum degree of 7-10 Pa and the temperature of-2 ℃, and then treated for 1-5 h under the environment with the vacuum degree of 1-5 Pa and the temperature of 25-30 ℃.

Further, there is a temperature change from the sublimation drying to the dehydration drying, and three temperature ranges are involved in the dehydration drying process, and when the temperature is increased or decreased from the previous temperature range to the next temperature range, the magnitude of the temperature increase or decrease rate may also affect the quality of the prepared glutinous rice flour, in this embodiment, it is more preferable that: heating the filter cake from-50 to-60 ℃ to-8 to-12 ℃ at the speed of 10 to 15 ℃/h under the vacuum degree of 5 to 10Pa, and preserving the heat for 20 to 40 min; reducing the vacuum degree to 7-10 Pa, heating to-2 ℃ at the speed of 10-15 ℃/h, and preserving the heat for 1-2 h; then reducing the vacuum degree to 1-5 Pa, raising the temperature to 25-30 ℃ at the rate of 20-25 ℃, and preserving the temperature for 1-5 h.

And step S50, mixing the limiting gelatinized glutinous rice flour with raw glutinous rice flour to prepare the limiting gelatinized modified glutinous rice flour.

And after the limiting gelatinized glutinous rice flour is prepared by freeze drying, backfilling the limiting gelatinized glutinous rice flour into raw glutinous rice flour according to a certain proportion, fully stirring until the limiting gelatinized glutinous rice flour is uniformly mixed to prepare the limiting gelatinized modified glutinous rice flour, and bagging and packaging after the uniform mixing to obtain the modified glutinous rice flour product correspondingly. According to the characteristics of the prepared limiting gelatinized modified glutinous rice flour and the comprehensive consideration of the quality of the corresponding prepared quick-frozen product, the mass fraction of the limiting gelatinized glutinous rice flour in the limiting gelatinized modified glutinous rice flour is preferably 20-100%, the backfill proportion of the limiting gelatinized glutinous rice flour is properly adjusted in the interval, and the actual requirements of the glutinous rice flour with various characteristics and different requirements can be met.

According to the technical scheme provided by the invention, the restricted gelatinization treatment is firstly carried out on the raw glutinous rice flour, then the restricted gelatinization glutinous rice flour is prepared by freeze drying, then the restricted gelatinization glutinous rice flour is backfilled into the raw glutinous rice flour to prepare the restricted gelatinization modified glutinous rice flour, and the restricted gelatinization treatment of the glutinous rice flour has at least the following three advantages: (1) the water absorption performance of the glutinous rice flour is effectively improved, the molecular mobility of the amorphous starch region is improved under the combined action of water and heat energy, so that the radial and tangential swinging of molecular chains in the crystalline region and the amorphous region is enhanced, and favorable conditions are created for rearrangement; reversible expansion of starch grains occurs, the reversible expansion of the amorphous area applies pressure to the crystalline area of the amylopectin to enable the crystalline area to generate certain fluidity, the excessive moisture and the temperature rise in a certain range can promote the fluidity of the glucan chain to be enhanced, the generation of the popularity enables the double helix structure to realize limited movement, thereby completing the transformation from nematic phase to smectic phase, and the orderliness of the double helix structure is improved no matter in the lamellar structure of the amorphous area or in the side chain double helix of the amylopectin; in the limiting gelatinization process of the glutinous rice flour, the starch grains reach the melting point temperature, wherein the microcrystalline bundles are disintegrated, hydrogen bonds in molecules are partially broken, the structure of the starch grains becomes looser, water molecules can enter more easily, the water absorption rate of the glutinous rice flour can be effectively increased, and the cracking rate and the water loss of finished frozen dough sheets are reduced. (2) The restrictive gelatinization treatment of the glutinous rice flour is a green method for modifying natural biological macromolecules, can effectively increase the resistant starch content in starch foods, realizes the low digestibility of the glutinous rice flour, and better meets the public demand of low-calorie foods. (3) The restricted gelatinization treatment of the glutinous rice flour can improve the physical and chemical properties of the glutinous rice flour and the freezing and boiling performances of a quick-frozen product, the glutinous rice flour after the restricted gelatinization has higher resistant starch content, gelatinization temperature and energy storage modulus, and the gelatinization temperature range is effectively reduced, so that the frozen product is easier to boil.

The technical solutions of the present invention are further described in detail below with reference to specific examples and drawings, it should be understood that the following examples are merely illustrative of the present invention and are not intended to limit the present invention.