阅读说明：本技术 一种通过冷冻粉碎制备糯米粉的方法 (A method for preparing glutinous rice flour by freezing and pulverizing ) 是由 丁文平 张晨 庄坤 王月慧 王国珍 陈曦 孙周亮 王志颖 于 2019-12-19 设计创作，主要内容包括：本发明公开一种通过冷冻粉碎制备糯米粉的方法,包括以下步骤：对糯米进行除杂后清洗、沥干,得到清洗后的糯米；将所述清洗后的糯米用水浸泡后,沥干并破碎,得到糯米破碎料；对所述糯米破碎料进行预冷冻处理,然后在冷冻状态下进行超微粉碎,得到糯米粉碎料并封装；使封装后的所述糯米粉碎料恢复至室温,得到糯米粉。本发明通过先将糯米粉碎料进行预冷冻后,在冷冻状态下进行粉碎,减小了糯米粉的平均粒径和破损淀粉量,糯米粉粒径小且分布均匀,很大程度上增加了糯米粉的比表面积,使得糯米粉的吸水性、溶解性、冻融稳定性等得以提高,改善了糯米粉的综合品质。(The invention discloses a method for preparing glutinous rice flour by freezing and crushing, which comprises the following steps: removing impurities from the glutinous rice, cleaning, and draining to obtain cleaned glutinous rice; soaking the washed sticky rice in water, draining and crushing to obtain a sticky rice crushed material; pre-freezing the crushed glutinous rice materials, then carrying out superfine crushing in a frozen state to obtain crushed glutinous rice materials, and packaging; and recovering the packaged glutinous rice crushed material to room temperature to obtain glutinous rice flour. According to the invention, the crushed glutinous rice flour is pre-frozen and then crushed in a frozen state, so that the average grain size and the amount of damaged starch of the glutinous rice flour are reduced, the grain size of the glutinous rice flour is small and uniformly distributed, the specific surface area of the glutinous rice flour is increased to a great extent, the water absorption, the solubility, the freeze-thaw stability and the like of the glutinous rice flour are improved, and the comprehensive quality of the glutinous rice flour is improved.)

1. A method for preparing glutinous rice flour by freeze-pulverization is characterized by comprising the following steps:

removing impurities from the glutinous rice, cleaning, and draining to obtain cleaned glutinous rice;

soaking the washed sticky rice in water, draining and crushing to obtain a sticky rice crushed material;

pre-freezing the crushed glutinous rice materials, then carrying out superfine crushing in a frozen state to obtain crushed glutinous rice materials, and packaging;

and recovering the packaged glutinous rice crushed material to room temperature to obtain glutinous rice flour.

2. The method for preparing glutinous rice flour by freeze-pulverization according to claim 1, wherein the step of removing impurities from glutinous rice, washing and draining to obtain washed glutinous rice comprises:

the method comprises the steps of screening the glutinous rice, removing small-particle impurities, adding the glutinous rice into clear water, stirring, standing for 8-10 min, removing suspended impurities, fishing out the glutinous rice, washing, and draining to obtain the washed glutinous rice.

3. The method for preparing glutinous rice flour by freeze-pulverization according to claim 1, wherein the step of soaking the washed glutinous rice in water, draining and pulverizing to obtain a pulverized material of glutinous rice comprises:

the soaking time is 2-3 h; and/or the presence of a gas in the gas,

the particle size of the broken glutinous rice material is 20-60 meshes.

4. The method for preparing glutinous rice flour by freeze-pulverization according to claim 1, wherein the step of pre-freezing the pulverized glutinous rice material, then micronizing it in a frozen state to obtain a pulverized glutinous rice material, and packaging:

the freezing temperature of the pre-freezing treatment is-190 to-200 ℃, and the freezing time is 30 to 100 s.

5. The method for preparing glutinous rice flour by freeze-pulverization according to claim 4, wherein the pre-freezing treatment of the pulverized material of glutinous rice, followed by the ultra-pulverization in a frozen state to obtain the pulverized material of glutinous rice and the packaging, comprises:

and putting the broken glutinous rice material into liquid nitrogen to soak for 30-100 s.

6. The method for preparing glutinous rice flour by freeze-drying and pulverization according to claim 5, wherein the step of immersing the pulverized material of glutinous rice in liquid nitrogen for 30 to 100 seconds comprises:

the volume ratio of the mass of the broken glutinous rice material to the liquid nitrogen is (2-3): 5.

7. the method for preparing glutinous rice flour by freeze-pulverization according to claim 1, wherein the step of pre-freezing the pulverized glutinous rice material, then micronizing it in a frozen state to obtain a pulverized glutinous rice material, and packaging:

the particle size of the glutinous rice crushed material is 300-400 meshes.

8. The method for preparing glutinous rice flour by freeze-pulverization according to claim 1, wherein the step of subjecting the pulverized glutinous rice material to pre-freezing treatment and then to ultra-fine pulverization in a frozen state to obtain the pulverized glutinous rice material and packaging, the ultra-fine pulverization step comprises:

and grinding the broken glutinous rice materials for 15-60 min by a hammer mill in a frozen state.

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 method for preparing glutinous rice flour by freezing and crushing.

Background

Glutinous rice is mainly used for making traditional special flavor food, along with the development of modern society and the improvement of the living standard of people, the requirements of people on the flavor, the quality and the variety of the food are continuously increased, the glutinous rice is also applied to processing the glutinous rice flour from the simplification of the traditional food preparation, the application range of the glutinous rice flour is continuously expanded, and particularly, the appearance and the popularization of the quick-frozen food of the modern glutinous rice flour and the conversion and utilization of the modern biotechnology on starch ensure that the demand of the glutinous rice flour is continuously increased. At present, the glutinous rice flour processing industry in China is still in a growth stage, the scale of processing enterprises is small, the processing enterprises are dispersed, the automation degree is not high, the added value of products is low, and the deep processing is insufficient.

The processing of the glutinous rice flour is developed from the ancient folk traditional manual stone grinding method to the present, and mainly comprises dry grinding, semi-dry grinding and wet water grinding, and the quality of the glutinous rice flour is influenced to a certain extent by the difference of the processing methods. Numerous studies have shown that cakes made with rice flour prepared by different processing methods have significant differences in texture, volume and appearance. The research on the method for milling the glutinous rice flour is less, the technological process of the whole processing process is not scientifically analyzed and reasonably planned, and theoretical guidance is lacked, which is an important reason that the technical level of the glutinous rice flour processing industry in China is laggard and the glutinous rice flour milling method is in disordered development.

In the crushing of dry rice, the amount of damaged starch produced from rice increases with the processing time. Damage to starch results in greater water absorption, lower initial gelatinization temperature, and lower gelatinization enthalpy. In the process of crushing the dry rice, the temperature of the materials is increased, the flour is easy to deform, the content of damaged starch is high, the fineness is not uniform, and the mouthfeel, the color, the nutrition and the like are not ideal, but the protein content of the glutinous rice flour crushed by the dry rice is high, the energy consumption is low, no wastewater is generated, and the cost is relatively low. The semi-dry method crushing is also called post-washing dry grinding, and the difference from dry rice crushing is that rice washing is carried out before half-method crushing, impurities and dust in the rice are washed away, meanwhile, the rice is guaranteed to be fully absorbed with moisture, the rice is crisp and easy to crush, 2-3 times of rice washing is generally needed, excess moisture is drained after the rice washing for crushing, water is not added during crushing, when the moisture content of milled rice is high, drying is carried out before screening, and after the required granularity is reached, a finished product is measured and packaged.

The quality of glutinous rice flour processed by the semidry method is better than that of dry milled powder, starch particles of the glutinous rice are moderately swelled and loosened in the moistening process, the glutinous rice flour is easier to crush compared with the dry milled powder, the crushed particle size is smaller, the amount of damaged starch is lower than that of the dry milled powder, but the water-soluble components in the rice grains are reduced. The food processing quality of the water milled powder is also superior to that of the dry milled powder. Comprehensive evaluation shows that the water milling powder has fine granularity, less damaged starch, fine and smooth powder quality, softness and tenderness, but the water milling process needs more equipment, has long process, high water consumption and power consumption and can cause loss of nutrient components in the glutinous rice powder.

Disclosure of Invention

The invention mainly aims to provide a method for preparing glutinous rice flour by freezing and crushing, aiming at improving the comprehensive quality of the glutinous rice flour.

In order to achieve the above objects, the present invention provides a method for preparing glutinous rice flour by freeze-pulverization, comprising the steps of:

removing impurities from the glutinous rice, cleaning, and draining to obtain cleaned glutinous rice;

soaking the washed sticky rice in water, draining and crushing to obtain a sticky rice crushed material;

pre-freezing the crushed glutinous rice materials, then carrying out superfine crushing in a frozen state to obtain crushed glutinous rice materials, and packaging;

and recovering the packaged glutinous rice crushed material to room temperature to obtain glutinous rice flour.

Optionally, the step of removing impurities from the sticky rice, cleaning the sticky rice, and draining the sticky rice to obtain the cleaned sticky rice comprises:

the method comprises the steps of screening the glutinous rice, removing small-particle impurities, adding the glutinous rice into clear water, stirring, standing for 8-10 min, removing suspended impurities, fishing out the glutinous rice, washing, and draining to obtain the washed glutinous rice.

Optionally, after soaking the washed glutinous rice in water, draining and crushing the glutinous rice to obtain a crushed glutinous rice material, the step of:

the soaking time is 2-3 h; and/or the presence of a gas in the gas,

the particle size of the broken glutinous rice material is 20-60 meshes.

Optionally, the step of pre-freezing the crushed glutinous rice materials, then carrying out superfine crushing in a frozen state to obtain crushed glutinous rice materials and packaging:

the freezing temperature of the pre-freezing treatment is-190 to-200 ℃, and the freezing time is 30 to 100 s.

Optionally, in the step of pre-freezing the broken glutinous rice materials, then performing ultra-micro crushing in a frozen state to obtain broken glutinous rice materials and packaging, the pre-freezing step includes:

and putting the broken glutinous rice material into liquid nitrogen to soak for 30-100 s.

Optionally, the step of soaking the broken glutinous rice materials in liquid nitrogen for 30-100 s comprises the following steps:

the volume ratio of the mass of the broken glutinous rice material to the liquid nitrogen is (2-3): 5.

optionally, the step of pre-freezing the crushed glutinous rice materials, then carrying out superfine crushing in a frozen state to obtain crushed glutinous rice materials and packaging:

the particle size of the glutinous rice crushed material is 300-400 meshes.

Optionally, the crushed glutinous rice material is pre-frozen and then subjected to superfine crushing in a frozen state to obtain crushed glutinous rice. In the step of feeding and packaging, the step of micronizing comprises:

and grinding the broken glutinous rice materials for 15-60 min by a hammer mill in a frozen state.

According to the technical scheme provided by the invention, the glutinous rice crushed materials are pre-frozen and then crushed in a frozen state, so that the average grain size and the amount of damaged starch of the glutinous rice flour are reduced, the utilization rate of raw materials is high, the characteristics of the external color, fragrance, taste and the like of the glutinous rice are kept, the molecular structure, the components and the activity of the original nutrient substances can be furthest preserved, the absorption of a human body on the nutrient components and trace elements in the glutinous rice flour is favorably improved, meanwhile, the grain size of the glutinous rice flour obtained by superfine crushing is small and is uniformly distributed, the specific surface area of the glutinous rice flour is greatly increased, the water absorption, the solubility, the freeze-thaw stability and the like of the glutinous rice flour are improved, and the comprehensive quality of the glutinous rice flour is improved.

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 showing one embodiment of the method for preparing glutinous rice flour by freeze-pulverization according to the present invention;

FIG. 2 shows the results of particle size distribution tests of glutinous rice flour prepared by different pulverization methods;

fig. 3 is a test result of whiteness and damaged starch content of the glutinous rice flour prepared by different pulverization methods.

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.

In the traditional glutinous rice flour production mode, the damage degree of the crushing mode to the glutinous rice flour is large, the content of damaged starch is obviously increased, functional substances such as phenols and the like and protein are seriously damaged due to heating, the appearance and the smell of the glutinous rice flour are greatly influenced, the color and the luster of the glutinous rice flour become dark, the natural glutinous fragrance of the cooked glutinous rice becomes light, and the taste is obviously deteriorated. Meanwhile, the water absorption, water retention and dispersibility of the glutinous rice flour are reduced. In addition, the traditional crushing mode produces glutinous rice flour with poor fineness, low freeze-thaw stability and uneven particle size distribution, so that the added value of the product is reduced, and the problem of cracking of the dough skin often occurs when the glutinous rice flour is used as a raw material to produce quick-frozen food. Therefore, most of the glutinous rice flour is not suitable for being produced as special flour for quick-frozen food, and the development of the glutinous rice flour industry is restricted.

In view of the above, the present invention provides a method for preparing glutinous rice flour by freeze-crushing, which improves the overall quality of glutinous rice flour, and fig. 1 shows an embodiment of the method for preparing glutinous rice flour by freeze-crushing according to the present invention. Referring to fig. 1, in this embodiment, the method for preparing glutinous rice flour by freeze-pulverization includes the following steps:

s10, removing impurities from the sticky rice, cleaning, and draining to obtain cleaned sticky rice;

firstly, sieving glutinous rice by a 5-10-mesh sieve, removing small particle impurities mixed in the glutinous rice, collecting the glutinous rice on the sieve, then adding the glutinous rice into a water tank filled with clear water, stirring, standing for 8-10 min, then removing suspended impurities on the water surface, then fishing out the glutinous rice from the water tank, placing the glutinous rice into a cleaning basket, flushing with clear water, and draining until no water drops, thus obtaining the cleaned glutinous rice.

Step S20, soaking the washed sticky rice in water, draining and crushing to obtain a broken sticky rice material;

and after impurity removal and cleaning are completed, soaking the glutinous rice in water until the volume of the glutinous rice expands, wherein the soaking time can be set to 2-3 hours, draining the glutinous rice until no water drops after soaking, and then crushing the glutinous rice by a crusher to obtain a crushed glutinous rice material. Wherein, when carrying out a large amount of man-hour to sticky rice, can accomplish the back at cleaning work, carry sticky rice in the soaking pool that is equipped with the clear water with burying scraper conveyor, the filter plate can be installed to the soaking pool bottom, finishes soaking after, passes through the filter plate drains sticky rice.

In step S20, only a simple crushing treatment of the glutinous rice is required, and the glutinous rice is not required to be crushed to reduce the amount of starch damage, specifically, the grain size of the obtained crushed glutinous rice is only required to be 20 to 60 mesh.

Step S30, pre-freezing the broken glutinous rice materials, then carrying out superfine grinding in a frozen state to obtain broken glutinous rice materials and packaging;

in the embodiment, the freezing temperature of the pre-freezing treatment is-190 to-200 ℃, and the freezing time is 30 to 100 seconds. The pre-freezing treatment can be realized by freezing equipment, and in consideration of energy conservation and simplicity and convenience of the method, the pre-freezing treatment is preferably performed by a liquid nitrogen soaking mode, and the specific operation mode can be as follows: and putting the broken glutinous rice material into liquid nitrogen to soak for 30-100 s.

Further, when the pre-freezing treatment is carried out through liquid nitrogen, the volume ratio of the mass of the broken glutinous rice material to the liquid nitrogen is (2-3): 5, so, both can the broken material of glutinous rice soaks in liquid nitrogen completely to carry out the prefreezing with whole glutinous rice crushed aggregates simultaneously and handle, the refrigeration effect preferred can avoid the liquid nitrogen use amount excessive and lead to unnecessary extravagant again.

And after pre-freezing the crushed glutinous rice materials, carrying out superfine grinding on the crushed glutinous rice materials when the crushed glutinous rice materials are in a frozen state, so as to obtain the crushed glutinous rice materials with the particle size of 300-400 meshes. Or the crushed glutinous rice materials subjected to pre-freezing treatment can be subjected to superfine crushing in a low-temperature environment of not higher than-50 to-70 ℃. Further, the superfine grinding can be realized by grinding for 15-60 min through a hammer mill. The hammer mill is adopted to carry out superfine grinding on the frozen glutinous rice crushed material, the average grain diameter and the amount of damaged starch of the glutinous rice flour can be obviously reduced, the yield of frozen grinding is higher than that of dry grinding under the condition of using the same mill, the utilization rate of raw materials is improved, the power consumption and the generation of waste water are reduced compared with a water grinding method, and the frozen superfine grinding process can be used as a good choice for replacing the traditional dry grinding method or wet grinding method.

And step S40, recovering the packaged glutinous rice crushed material to room temperature to obtain glutinous rice powder.

And after the micronization is finished, immediately packaging the obtained glutinous rice crushed material and standing until the temperature is recovered to room temperature, wherein the glutinous rice crushed material is balanced and rewarming in the process, so that the glutinous rice flour is prepared. This balanced rewarming process can go on in the former feed bin of glutinous rice, also, the glutinous rice crushed aggregates that obtains with super little grinding encapsulates the back immediately, shifts to the broken material of glutinous rice and stores the storehouse and stews to recovering the room temperature, and at this in-process, the endothermic effect of glutinous rice crushed aggregates can store the broken material of glutinous rice in the storehouse and carry out the precooling to the broken material of glutinous rice, is favorable to practicing thrift the processing technology cost.

According to the technical scheme provided by the invention, the glutinous rice crushed materials are pre-frozen and then crushed in a frozen state, so that the average particle size and the amount of damaged starch of the glutinous rice flour are reduced, the utilization rate of raw materials is high, the characteristics of the external color, fragrance, taste and the like of the glutinous rice are kept, the molecular structure, components and activity of original nutrient substances can be furthest preserved, the absorption of a human body on the nutrient components and trace elements in the glutinous rice flour is favorably improved, meanwhile, the glutinous rice flour obtained through superfine crushing has small particle size and uniform distribution, the specific surface area of the glutinous rice flour is increased to a great extent, and the water absorption, the solubility, the freeze-thaw stability and the like of the glutinous rice flour are improved; in addition, compared with a water milling method, the preparation method of the glutinous rice flour provided by the invention reduces the power consumption, reduces the generation of wastewater, and is more energy-saving and environment-friendly.

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.