A processing method for preparing wholegrain rice by hulling grains

Abstract

The present invention discloses a processing method for preparing whole grain rice by hulling grains, and the processing method comprises the following steps: subjecting the hulled grains to steam explosion treatment in water vapor at a temperature of 130°C - 230°C and a pressure of 0.17 MPa - 2.70 MPa, with a pressure holding time of 10 s - 600 s, and then performing drying, separation and hulling operations to obtain complete hulls and complete whole grain rice. This method has good hulling effects on wheat, millet, broomcorn millet, sorghum, rice, highland barley, oats, coix seed, barley, buckwheat, quinoa or amaranth, and particularly has obvious improvement in hulling effects on pseudo-cereals such as tartary buckwheat, common buckwheat, hulled oats, etc. This method has a high whole rice rate, a high hulling rate, a small loss rate, a short processing cycle, complete separation of the husk, low energy consumption and high efficiency, and the prepared whole grain rice is rich in nutrition, has a good taste, a strong fragrance and a short gelatinization time.

Description

Technical Field

[0001] The present invention belongs to the field of grain processing. In particular, it relates to a processing method for preparing whole grain rice by hulling grains. Background Art

[0002] Grain hulling is an important link in the grain processing process. The speed and quality of hulling are directly related to the cost of hulling and the quality of the product. Due to factors such as the size, shape, hardness of the texture, and the tightness between the hull and the grain of the grain, the hulling devices and methods used are also different.

[0003] At present, the relatively mature hulling technologies are for wheat and paddy rice. Most of the hulling processing technologies for other grains are improved from those for wheat and paddy rice. Due to the different sizes, shapes, and properties of each grain raw material, they are not completely applicable, resulting in poor product quality. For many grains, because there is no suitable hulling device, the grains are unevenly stressed during the hulling process, resulting in phenomena such as low head rice rate, many broken grains, many cracked grains, and incomplete hulling occurring frequently. Sometimes, one-time hulling cannot be achieved, and multiple repeated hulling is often required. Even for relatively mature paddy rice hulling equipment, due to different paddy rice varieties, it is not easy to determine the hulling technical parameters, which leads to a decline in the quality of the hulled rice. Some grains, such as tartary buckwheat, have smaller achenes, oblong tops, blunt edges, and many ventral grooves. The kernels of tartary buckwheat are relatively brittle, the husks have high toughness, and the husks and kernels are closely attached, which makes its hulling characteristics different from other hulled grains. Traditional hulling methods and equipment cannot meet the requirements of tartary buckwheat hulling, and it is extremely easy to result in a low whole kernel rate, a relatively high kernel breakage rate, low product quality, and not meeting the requirements for granular food consumption. Fan Weiguo (Research on the Surface Hardening Technology of Tartary Buckwheat and Improvement Experiment of Its Huller [D]. Northwest A&F University, 2017) improved a non-thermal hulling method and huller for tartary buckwheat with dynamic pressure regulation and grinding, and the hulling rate can reach 84.44%, but the whole kernel rate is only 80.83%. Liu Yanhui et al. (Liu Yanhui, Du Wenliang, Wu Yingsi. Optimization of the Hulling Process and Main Parameters of Tartary Buckwheat [J]. Journal of Agricultural Mechanization Research, 2008(12):131 - 133) provided a steam wetting - sand table type and steam wetting - rubber type hulling method, but the whole and semi-kernel rate is only 37.6%. Some grains, such as oats, have concave inner glumes in the fruit, and the contact area of the hooked part between the inner and outer glumes is relatively large, making the hooking strength relatively large. Because the inner glume cannot be pressed into the rubber surface, the purpose of longitudinal rubbing and hulling cannot be achieved, and a rubber roll rice huller cannot be used for hulling. Generally, an impact hulling method is adopted, but during the impact process, oats are easy to break, increasing the cracked rice rate. The broken grains are easy to produce lipase and are prone to lipid oxidation reaction, causing the oats to become rancid. How to obtain a high whole kernel rate is one of the key technical problems in the hulling of such grains. In the current hulling technologies for tartary buckwheat and oats, in order to improve the whole kernel rate of hulling, processes such as soaking, steaming, drying, hulling, and drying of the raw materials are required. This kind of cooked hulling method is often used in the hulling of oats and tartary buckwheat, but this kind of cooked hulling method dissolves the water-soluble substances in the raw materials, causing a certain loss of nutrition. At the same time, the energy consumption and water consumption in cooked hulling production are relatively high, with an electricity consumption of about 20 kW·h / t and a water consumption of about 3 - 4 m 3 / t, which is time-consuming and laborious, with low production efficiency and high costs. During the hulling process, the quality of the grains changes. In addition, there are also some dynamic grinding hulling technologies. Through low-pressure milling, the outer husks at the ridges and cone tips of tartary buckwheat grains are ground and exposed to white, reducing the binding force between the three petals of the outer husk. Then, low-pressure kneading is applied to tartary buckwheat, causing the husk and kernel to peel off. The obtained tartary buckwheat kernels are complete, but the tartary buckwheat husks are incomplete, and its application is limited.

[0004] In view of the technical defects existing in the above-mentioned prior art, the present invention discloses a processing method for preparing whole grain rice by hulling grains. Summary of the Invention

[0005] An object of the present invention is to provide a processing method for preparing whole grain rice by hulling grains, which has a high whole rice rate, a high hulling rate, and a small loss rate; compared with the traditional hulling method, it has a short processing cycle, complete hull peeling, low energy consumption, and high efficiency.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a processing method for preparing whole grain rice by hulling grains, and the processing method includes the following steps:

[0008] Performing steam explosion treatment on the hulled grains in water vapor at a temperature of 130°C - 230°C and a pressure of 0.17 MPa - 2.70 MPa, and the pressure holding time is 10 s - 600 s;

[0009] Then, after drying and separation and hulling operations, complete husks and complete whole grain rice are obtained.

[0010] The steam explosion method adopted by the present invention can completely remove the wheat husks of grains under appropriate process parameters to obtain complete whole grain rice. This method has a short processing cycle, complete hull peeling, a high whole rice rate, a high hulling rate, a small loss rate, low energy consumption, and high efficiency, and the husks are complete with few broken husks, which does not affect secondary sales.

[0011] The grain hulling method of the present invention is applicable to various hulled grains, including but not limited to one or more of wheat, millet, broomcorn millet, sorghum, rice, highland barley, oats, coix seed, barley, buckwheat, quinoa, or amaranth.

[0012] According to the specific embodiments of the present invention, the above-mentioned hulled grains can be pre-cleaned, sorted, and screened before hulling to obtain clean raw materials with plump grains of the same size, and then put into subsequent operations.

[0013] Further, the buckwheat is tartary buckwheat or common buckwheat, and the oats are hulled oats.

[0014] The above-mentioned tartary buckwheat, common buckwheat, and hulled oats belong to the category of pseudocereals. Due to their special hull-kernel structure, traditional dehulling methods and equipment cannot meet the dehulling requirements, easily resulting in a low whole-kernel rate, a high rate of broken wheat kernels, a low product quality, and not meeting the requirements for grain consumption. The method of the present invention uses techniques such as internal and external pressure difference puffing, high-pressure steaming, high-temperature sterilization, and high-temperature enzyme inactivation to process hulled grains and pseudocereals, with a high whole-rice rate, a high dehulling rate, and a small loss rate. This method has a short processing cycle, complete hull peeling, low energy consumption, and high efficiency. The whole-grain rice obtained has rich nutrition, a good taste, a strong fragrance, and a small loss of bioactive ingredients.

[0015] Furthermore, it should be noted that the term "whole-grain rice" used in the present invention refers to the wheat kernels obtained by subjecting grains to steam explosion and ripening.

[0016] In the present invention, when processing grain dehulling by steam explosion technology, the processing conditions of the above-mentioned steam explosion (for example, the temperature, pressure, and pressure-holding time of water vapor, etc.) can be considered for single-factor or multi-factor level adjustment in actual applications. There is no absolute correlation between these processing conditions. For example, only the temperature of water vapor can be changed, or the temperature, pressure, and pressure-holding time of water vapor can be changed simultaneously.

[0017] According to a specific embodiment of the present invention, the temperature of the water vapor is 130°C - 230°C, for example, it can be 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, and any sub-range composed of them.

[0018] According to a specific embodiment of the present invention, the pressure of the water vapor is 0.17 MPa - 2.70 MPa, for example, it can be 0.17 MPa, 0.3 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.9 MPa, 1.0 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.45 MPa, 1.5 MPa, 1.6 MPa, 1.7 MPa, 1.9 MPa, 2.1 MPa, 2.3 MPa, 2.6 MPa, 2.7 MPa, and any sub-range composed of them.

[0019] According to a specific embodiment of the present invention, the pressure-holding time is 10 s - 600 s, for example, it can be 10 s, 30 s, 80 s, 90 s, 150 s, 200 s, 250 s, 300 s, 350 s, 450 s, 500 s, 600 s, and any sub-range composed of them.

[0020] The present invention can effectively hull grains by controlling the temperature of water vapor, the pressure of water vapor, and the pressure-holding time, with a high whole rice rate, a low broken rice rate, and a high hulling rate. During steam explosion, the explosion pressure is one of the key control factors. When the pressure is lower than 0.17 MPa, the pressure difference from the air is small and it cannot play the role of explosion; when the pressure is higher than 2.70 MPa, the surface of the raw material is prone to being pasted and the epidermis cracks, affecting the integrity of the particle appearance. The pressure-holding time is also one of the key control factors. When the pressure-holding time is less than 10 s, the steam pressure is not sufficient to improve the hardness of the surface layer of wheat kernels, which is prone to problems such as broken rice. And when the pressure is instantaneously released, the increased gap between the wheat husk and the wheat kernel is limited and the hulling rate is low. While when the pressure-holding time exceeds 600 s, the long-term high pressure is prone to cause the fragmentation of wheat kernels, which will also affect its integrity.

[0021] The technical solution provided by the present invention is particularly effective in hulling tartary buckwheat and oats. Placing the hulled tartary buckwheat and oats in a high-temperature and high-pressure environment, the raw materials after adjusting the moisture are cooked by superheated steam within a short time (10 s - 600 s), reducing the cooking time. After high-pressure steam steaming, the hardness of the surface layer of tartary buckwheat kernels can be greatly improved. When the pressure is instantaneously released, a large amount of gas between the wheat kernels and the wheat husk instantaneously expands, increasing the gap between the wheat husk and the wheat kernel, reducing the external force for separating the wheat kernel and the wheat husk, with a high whole rice rate, a low broken rice rate, and a high hulling rate. The traditional tartary buckwheat and oat hulling processes use the method of soaking - high-temperature steaming - drying - hulling. The high-temperature steaming takes a long time, generally 30 min - 90 min. After drying, hulling is carried out. When the moisture content after drying is low, hulling is easy but the whole rice rate is low. When the moisture content after drying is high, the whole rice rate is high but hulling is difficult and multiple hulling operations are required, increasing the operation time and cost.

[0022] Further, the processing method further includes soaking the hulled grains in water or a fiber softening solution, stirring evenly and then standing still to obtain a pretreated material. The water or the fiber softening solution is n times the mass of the grains, where 0 < n ≤ 3.

[0023] Further, the fiber softening solution includes but is not limited to one or more of cellulase, hemicellulase, xylanase, or β-glucanase.

[0024] Further, the standing still time is 0 h - 24 h.

[0025] The selection of the standing still time should not exceed 24 h because under higher moisture conditions, the surface of the grains is prone to mildew and food safety is challenged.

[0026] Further, the processing method further includes pre-drying the pretreated material. The pre-drying treatment conditions are a temperature of 4°C - 30°C and a time of 0 h - 4 h.

[0027] Further, after the pre-treatment material is pre-dried, the water content of the pre-treatment material is 4%-45%.

[0028] Further, the processing method further includes grading and packaging after drying.

[0029] Further, the drying includes drying, fluidized bed drying, microwave drying, infrared drying or pneumatic drying; preferably, the drying temperature is 20°C-100°C, and the drying time is 1-3 h.

[0030] Further, the separation includes but is not limited to winnowing, gravity separation or screening.

[0031] During drying, the humidity is controlled at 50%-85%. Multiple turnings can be carried out during drying to facilitate rapid water removal. After drying, the moisture content of the chaff and grains can be reduced to less than 18%. The dried grains are graded into 2-6 grades. A rubber roll huller is used to initially separate the wheat husks and wheat kernels. Further separation of the chaff and grains is achieved through winnowing, gravity separation or screening. Broken rice is screened out, and whole grains are retained. The wheat kernels can be further processed such as flavor enhancement and flaking, and then vacuum packaged.

[0032] The beneficial effects of the present invention are as follows:

[0033] The present invention discloses a processing method for preparing whole grain rice by grain hulling. This method can effectively hull grains such as wheat, millet, broomcorn millet, sorghum, rice, highland barley, oats, coix seed, barley, buckwheat, quinoa, and amaranth, obtaining complete chaff and complete whole grain rice, with a high whole rice rate, high hulling rate, and low loss rate. Compared with traditional hulling methods, it has a short processing cycle, complete separation of husk and kernel, low energy consumption, and high efficiency; especially, it has remarkable effects in hulling pseudo-cereals such as tartary buckwheat, common buckwheat, and hulled oats. The prepared pseudo-cereal chaff is complete, the whole hull rate of buckwheat is 85%-100%, with few broken hulls, which does not affect secondary sales. The prepared whole grain rice is rich in nutrition, with little loss of bioactive components, good taste, strong fragrance, and short gelatinization time, and can be cooked together with polished rice after being mixed in any proportion. Description of the Drawings

[0034] The following further describes in detail the specific embodiments of the present invention with reference to the drawings.

[0035] Figure 1 Showing the hulled tartary buckwheat whole grain rice in Example 1 (a is a mixture of tartary buckwheat husk and tartary buckwheat rice; b is tartary buckwheat whole grain rice; c is tartary buckwheat husk)

[0036] Figure 2 Showing the hulled common buckwheat whole grain rice in Example 2 (a is common buckwheat whole grain rice, b is common buckwheat husk)

[0037] Figure 3 Showing the dehulled hulless oat easy-cooking whole grain rice in Example 3

[0038] Figure 4 Showing the hulled proso millet instant whole grain rice after dehulling in Example 4 (a is the mixture of proso millet hulls and proso millet rice; b is the proso millet instant whole grain rice)

[0039] Figure 5 Showing the dehulled hulless oat easy-cooking whole grain rice in Example 5

[0040] Figure 6 Showing the tartary buckwheat without effective separation in Comparative Example 1

[0041] Figure 7 Showing the common buckwheat without effective separation in Comparative Example 2

[0042] Figure 8 Showing the tartary buckwheat without effective separation in Comparative Example 3 Detailed implementation manners

[0043] The present invention discloses a processing method for preparing whole grain rice by hulling grains. Those skilled in the art can draw on the content of this article and appropriately modify the process parameters to achieve it. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are all regarded as included in the present invention. The method and product of the present invention have been described through preferred embodiments, and those related can obviously make changes or appropriate alterations and combinations to the methods described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0044] To further understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0045] Unless otherwise specified, the reagents involved in the embodiments of the present invention are all commercially available products and can be obtained through commercial channels.

[0046] Example 1

[0047] The present invention provides a processing method for preparing tartary buckwheat whole grain rice by hulling tartary buckwheat, including the following steps:

[0048] 1) Cleaning: Removing impurities, color sorting, and grain sorting the hulled tartary buckwheat to obtain tartary buckwheat raw materials with uniform color and grain shape;

[0049] 2) Raw material pretreatment: Pour the cleaned tartary buckwheat raw materials into a container, wash them twice, soak them according to the mass ratio of tartary buckwheat raw materials: water = 1:1.5, stir evenly and then let stand for 2 h, and pre-dry at 30 °C for 1 h to obtain the pretreated materials;

[0050] 3) Steam explosion ripening: Place the pretreated materials in a steam explosion reactor, and perform steam explosion treatment with saturated water vapor at a temperature of 200 °C and a pressure of 1.45 MPa. The pressure holding time is 240 s to obtain the cooked tartary buckwheat after steam explosion.

[0051] 4) Drying and cooling: Dry the cooked tartary buckwheat in a hot air drying equipment for 1.5 h. The drying temperature is 50 °C and the humidity is 50%. During this period, turn it over several times and dry it until the moisture content is 16%. After drying, cool it to room temperature with air.

[0052] 5) Classification: Classify the dried cooked tartary buckwheat twice, and use a rubber roller huller to separate the tartary buckwheat husks and tartary buckwheat kernels respectively. Then perform air separation to separate the buckwheat husks and tartary buckwheat kernels to obtain whole grain tartary buckwheat rice and tartary buckwheat husks.

[0053] 6) Screening: Screen the whole grain tartary buckwheat rice to remove the tartary buckwheat husks and unhulled grains that cannot be completely separated.

[0054] 7) Packaging: Vacuum pack the whole grain tartary buckwheat rice and tartary buckwheat husks respectively.

[0055] The solution provided by the present invention shows good effects in tartary buckwheat hulling. The hulling rate of the obtained whole grain tartary buckwheat rice reaches 87.4%, the grain shape is complete, the broken rice rate is 3.2%, the whole kernel rate is 96.9%, the fragrance is strong, the taste is good, the obtained tartary buckwheat husks have a complete grain shape, are clean, have no broken rice, and the broken husk rate is 0.9%.

[0056] Example 2

[0057] The present invention provides a processing method for preparing sweet buckwheat whole grain rice by hulling sweet buckwheat, including the following steps:

[0058] 1) Cleaning: Remove impurities, color select, and size select the shelled sweet buckwheat raw materials to obtain sweet buckwheat raw materials with uniform color and grain shape.

[0059] 2) Raw material pretreatment: Pour the cleaned shelled sweet buckwheat into a container, wash it twice, soak it according to the mass ratio of shelled sweet buckwheat: water = 1:2.3, stir evenly and then let stand for 20 h, and pre-dry at 20 °C for 2 h to obtain the pretreated materials;

[0060] 3) Steam explosion and ripening: Place the pretreated material in a steam explosion reactor, and perform steam explosion treatment with saturated water vapor at a temperature of 160 °C and a pressure of 0.52 MPa. The pressure holding time is 180 s to obtain the ripened buckwheat after steam explosion.

[0061] 4) Drying and cooling: Dry the ripened buckwheat in a hot air drying equipment for 3 h at a drying temperature of 90 °C and a humidity of 50%. During this period, turn it over several times until the moisture content reaches 18%. After drying, cool it to room temperature by air cooling.

[0062] 5) Grading: Perform 4 times of grading on the dried ripened buckwheat, and use a rubber roll hulling machine to separate the buckwheat husk and buckwheat kernels respectively to obtain whole buckwheat grains and buckwheat husks.

[0063] 6) Screening: Screen the whole buckwheat grains to remove the broken grains.

[0064] 7) Aroma enhancement: Perform aroma enhancement treatment on the whole buckwheat grains with a roller baking machine for 30 min at a temperature of 137 °C until the moisture content is reduced to 5%, and then cool it to room temperature by air cooling.

[0065] 8) Packaging: Vacuum package the aroma-enhanced whole buckwheat grains and buckwheat husks respectively.

[0066] Mix 1 part by mass of the above-mentioned whole buckwheat grains with 1 - 3 parts of rice and then steam them. The obtained whole buckwheat rice has a strong aroma and is rich in nutrition.

[0067] The solution provided by the present invention shows good effects in buckwheat hulling. The hulling rate of the obtained whole buckwheat grains is 94.5%, the grain shape is complete, the broken rice rate is 1.8%, the whole kernel rate is 98.2%, the aroma is strong, the taste is good, the obtained buckwheat husks have a complete grain shape, are clean, without broken rice, and the broken husk rate is 0.7%.

[0068] Example 3

[0069] The present invention provides a processing method for preparing easy-cooking whole oat grains from hulled oats, including the following steps:

[0070] 1) Cleaning: Remove impurities and select grains from the raw hulled oat materials to obtain raw hulled oat materials with uniform grain shapes.

[0071] 2) Raw material pretreatment: Pour the cleaned raw hulled oat materials into a container, wash them once, soak them according to the mass ratio of hulled oats: water = 1:3, stir evenly and then let it stand for 5 h, and pre-dry them at 20 °C for 2 h to obtain the pretreated material;

[0072] 3) Steam explosion and ripening: Place the pretreated material in a steam explosion reactor, and conduct steam explosion treatment with saturated steam at a temperature of 180°C and a pressure of 0.90 MPa. The pressure holding time is 300 s to obtain the cooked hulled oats after steam explosion.

[0073] 4) Drying and cooling: Dry the cooked hulled oats in a hot air drying equipment for 3 h at a drying temperature of 100°C and a humidity of 40%. During this period, turn it over several times and dry until the moisture content is 13%. After drying, cool it to room temperature by air cooling.

[0074] 5) Grading: Conduct two - stage grading on the dried cooked hulled oats. Use a rubber roller huller to separate the hulled oats and the oat kernels respectively to obtain whole - grain hulled oats rice and hulled oats husks.

[0075] 6) Screening: Screen the whole - grain hulled oats rice to remove the broken grains.

[0076] 7) Aroma enhancement: Treat the whole - grain hulled oats rice with a roller baking machine for 15 min at a temperature of 150°C to reduce the moisture content to 5%, and then cool it to room temperature by air cooling to obtain the easy - to - cook whole - grain hulled oats rice.

[0077] 8) Flaking: Optionally, roll - press the easy - to - cook whole - grain hulled oats rice at a roll gap of 3 mm to form easy - to - cook whole - grain hulled oats flakes.

[0078] 8) Packaging: Vacuum - pack the hulled oats rice or the hulled oats flakes.

[0079] Add 1 part by mass of the above - mentioned hulled oats flakes to 3 parts by mass of boiling water and cook for 5 min. The obtained whole - grain oats porridge is rich in dietary fiber and β - glucan, has a strong fragrance, and is nutritious.

[0080] The solution provided by the present invention shows good results in the hulling of hulled oats. The hulling rate of the obtained whole - grain hulled oats rice reaches 85.5%, the grain shape is complete, the broken rice rate is 4.8%, the whole kernel rate is 95.2%, it has a strong fragrance, good taste, is clean, and has no broken rice.

[0081] Example 4

[0082] The present invention provides a processing method for preparing millet instant whole - grain rice by hulling millet, which includes the following steps:

[0083] 1) Cleaning: Conduct winnowing and impurity removal on the raw millet with husks to obtain clean raw millet.

[0084] 2) Raw material pretreatment: Pour the cleaned raw millet with husks into a container, soak it according to the mass ratio of raw millet with husks: water = 1:2.5, wash it twice, let it stand for 20 min, and then pre - dry it at 20°C for 2 h to obtain the pretreated material;

[0085] 3) Steam explosion and ripening: Place the pretreated material in a steam explosion reactor, and conduct steam explosion treatment with saturated steam at a temperature of 210 °C and a pressure of 1.81 MPa. The pressure holding time is 120 s to obtain the ripened proso millet after steam explosion.

[0086] 4) Drying and cooling: Dry the ripened proso millet after steam explosion in a hot air drying equipment for 2 h. The drying temperature is 110 °C and the humidity is 45%. During this period, turn it over several times and dry it until the moisture content is 8%. After drying, cool it to room temperature by air cooling.

[0087] 5) Hull separation: Combine winnowing and screening for the dried ripened proso millet to separate the proso millet hull and proso millet rice, and obtain the instant whole grain proso millet rice.

[0088] 6) Packaging: Package the instant whole grain proso millet rice. Preferably, package the instant whole grain proso millet rice by nitrogen filling.

[0089] Add 1 part by mass of the instant whole grain proso millet rice to 3 parts by mass of milk at 95 °C and brew for 3 - 5 min. The obtained instant whole grain proso millet rice soup is thick, has a strong fragrance, and a smooth taste.

[0090] The solution provided by the present invention shows good effects in the hulling of proso millet. The hulling rate of the obtained whole grain proso millet rice reaches 98%, the grain shape is complete, the broken rice rate is 1.2%, the whole kernel rate is 98.8%, it has a strong fragrance and a good taste. The obtained proso millet hull has a complete and clean grain shape and no broken rice.

[0091] Example 5

[0092] The present invention provides a processing method for preparing instant whole grain hulled oat rice from hulled oats, including the following steps:

[0093] 1) Cleaning: Remove impurities and select grains from the raw hulled oat materials to obtain hulled oat raw materials with uniform and consistent grain shapes.

[0094] 2) Steam explosion and ripening: Place the pretreated material in a steam explosion reactor, and conduct steam explosion treatment with saturated steam at a temperature of 200 °C and a pressure of 1.45 MPa. The pressure holding time is 500 s to obtain the ripened hulled oat after steam explosion.

[0095] 3) Cooling: Cool the ripened hulled oat to room temperature in an air cooling equipment.

[0096] 4) Grading: Conduct 2 - stage grading on the dried ripened hulled oat, and separately use a rubber roll rice huller to separate the hulled oat hull and hulled oat kernel to obtain the whole grain hulled oat rice and the hulled oat hull.

[0097] 5) Screening: Screen the whole grain hulled oat rice to remove the damaged grains.

[0098] 6) Aroma enhancement: The hulled oat whole grain rice is subjected to aroma enhancement treatment for 15 minutes using a roller baking machine at a temperature of 150 °C, and the moisture content is reduced to 5%, and then air-cooled to room temperature to obtain hulled oat easy-cooking whole grain rice.

[0099] 7) Packaging: The hulled oat rice or hulled oat flakes are vacuum-packed.

[0100] Add 1 part by mass of the above-mentioned hulled oat flakes to 2 parts by mass of white rice, and cook in an electric rice cooker according to the rice cooking mode. The obtained oat-white rice mixed rice has a soft and glutinous texture, a strong aroma, and is rich in nutrition.

[0101] The solution provided by the present invention has a good effect in hulling hulled oats. The obtained hulled oat whole grain rice has a relatively complete grain shape, a hulling rate of 89.9%, a broken rice rate of 15.5%, a whole kernel rate of 84.5%, a strong aroma, and a good taste.

[0102] Experimental Example 1

[0103] The lipase activity of the raw materials and the prepared whole grain rice in Examples 1 to 5 was tested. The test method was carried out in accordance with GB / T 5523-2008 Cereals and oils inspection - Determination of lipase activity in grains and oils. The obtained results are shown in Table 1.

[0104] Table 1 Comparison of lipase activity test data in Examples 1 to 5

[0105]

[0106]

[0107] It is not difficult to find through testing that the lipase activity of the whole grain rice prepared by the present invention is lower than that of the raw materials. After the grains in Examples 1 to 5 are hulled by the method provided by the present invention, the broken rice rate is lower, the whole rice rate is higher, less lipase is produced, and the original lipase activity is reduced, which inhibits the rancidity of the grains, extends the shelf life of the grains, and is beneficial for long-term storage.

[0108] Experimental Example 2

[0109] The gelatinization characteristics of the raw materials and the prepared whole grain rice in Examples 1 to 5 were tested. The test method was carried out in accordance with GB / T 24853-2010 Wheat, rye and their flours and starches - Determination of gelatinization characteristics - Rapid visco analyzer method. The obtained results are shown in Table 2.

[0110] Table 2 Comparison of gelatinization characteristics in Examples 1 to 5

[0111]

[0112] As can be seen from Table 2, the peak viscosity, minimum viscosity, final viscosity, retrogradation value, breakdown value, peak time, and gelatinization temperature of the whole grain rice are significantly lower than the corresponding values in the raw materials, indicating that the whole grain rice prepared by the method provided by the present invention can be cooked at a lower temperature in a shorter time, meeting the conditions for producing easily cookable or instant whole grain rice and effectively solving the technical problems of difficult cooking and storage of whole grain rice.

[0113] Comparative Example 1

[0114] Referring to the processing method for preparing whole grain rice by hulling tartary buckwheat in Example 1, only the steam explosion conditions were changed to a temperature of 200 °C, a pressure of 1.45 MPa, and a pressure holding time of 240 s, and other parameters were kept the same as in Example 1.

[0115] Under these steam explosion conditions, the temperature of the tartary buckwheat kernels was too high and gelatinization occurred, causing adhesion to the tartary buckwheat husks and unable to be effectively separated. The semi-kernel rate of the obtained tartary buckwheat rice was less than 50%, and the integrity rate of the tartary buckwheat husks was less than 40%.

[0116] Comparative Example 2

[0117] Referring to the processing method for preparing whole grain rice by hulling common buckwheat in Example 2, only the steam explosion conditions were changed to a temperature of 120 °C, a pressure of 0.10 MPa, and a pressure holding time of 60 s, and other parameters were kept the same as in Example 2.

[0118] Under these steam explosion conditions, the blasting pressure was small, the common buckwheat kernels adhered to the common buckwheat husks, and the common buckwheat kernels could not be effectively separated from the common buckwheat husks. The semi-kernel rate of the obtained common buckwheat rice was almost 0.

[0119] Comparative Example 3

[0120] Referring to the processing method for preparing whole grain rice by hulling tartary buckwheat in Example 1, only the steam explosion conditions were changed to a temperature of 120 °C, a pressure of 0.10 MPa, and a pressure holding time of 180 s, and other parameters were kept the same as in Example 1.

[0121] Under these steam explosion conditions, the blasting pressure was small, the tartary buckwheat kernels adhered to the tartary buckwheat husks, and the tartary buckwheat kernels could not be effectively separated from the tartary buckwheat husks. The obtained tartary buckwheat was broken rice without whole grains, and the tartary buckwheat husks were crushed without intact tartary buckwheat husks.

[0122] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation manners here. Any obvious changes or modifications derived from the technical solutions of the present invention still fall within the protection scope of the present invention.

Claims

1. A processing method for preparing whole grain rice by hulling grains, characterized in that, The processing method includes the following steps: 1) Cleaning: Removing impurities, color sorting, and grain sorting the hulled tartary buckwheat to obtain tartary buckwheat raw materials with uniform color and grain shape; 2) Raw material pretreatment: Pouring the cleaned tartary buckwheat raw materials into a container, washing twice, soaking according to the mass ratio of tartary buckwheat raw materials: water = 1:1.5, stirring evenly and then standing for 2h, pre-drying at 30°C for 1h to obtain the pretreated material; 3) Steam explosion ripening: Placing the pretreated material in a steam explosion reactor, performing steam explosion treatment with saturated steam at a temperature of 200°C and a pressure of 1.45MPa, with a pressure holding time of 240s, to obtain the steamed and exploded tartary buckwheat cooked material; 4) Drying and cooling: Drying the steamed and exploded tartary buckwheat cooked material in a hot air drying equipment for 1.5h, with a drying temperature of 50°C and a humidity of 50%, turning it over multiple times during the period, drying until the moisture content is 16%, and then cooling it to room temperature with air cooling; 5) Grading: Performing two-stage grading on the dried steamed and exploded tartary buckwheat cooked material, respectively using a rubber roll hulling machine to separate the tartary buckwheat husks and tartary buckwheat kernels, and then performing air separation to separate the buckwheat husks and tartary buckwheat kernels to obtain tartary buckwheat whole grain rice and tartary buckwheat husks; 6) Screening: Screening the tartary buckwheat whole grain rice to remove the incompletely separated tartary buckwheat husks and unhulled grains; 7) Packaging: Vacuum packaging the tartary buckwheat whole grain rice and tartary buckwheat husks separately.

2. A processing method for preparing whole grain rice by hulling grains, characterized in that, The processing method includes the following steps: 1) Cleaning: Removing impurities, color sorting, and grain sorting the hulled common buckwheat raw materials to obtain common buckwheat raw materials with uniform color and grain shape; 2) Raw material pretreatment: Pouring the cleaned hulled common buckwheat into a container, washing twice, soaking according to the mass ratio of hulled common buckwheat: water = 1:2.3, stirring evenly and then standing for 20h, pre-drying at 20°C for 2h to obtain the pretreated material; 3) Steam explosion ripening: Placing the pretreated material in a steam explosion reactor, performing steam explosion treatment with saturated steam at a temperature of 160°C and a pressure of 0.52MPa, with a pressure holding time of 180s, to obtain the steamed and exploded common buckwheat cooked material; 4) Drying and cooling: Drying the steamed and exploded common buckwheat cooked material in a hot air drying equipment for 3h, with a drying temperature of 90°C and a humidity of 50%, turning it over multiple times during the period, drying until the moisture content is 18%, and then cooling it to room temperature with air cooling; 5) Grading: Performing four-stage grading on the dried steamed and exploded common buckwheat cooked material, respectively using a rubber roll hulling machine to separate the common buckwheat husks and common buckwheat kernels to obtain common buckwheat whole grain rice and common buckwheat husks; 6) Screening: Screening the common buckwheat whole grain rice to screen out the broken grains; 7) Aroma enhancement: Performing aroma enhancement treatment on the common buckwheat whole grain rice with a roller baking machine for 30min, at a temperature of 137°C, reducing the moisture content to 5%, and cooling it to room temperature with air cooling; 8) Packaging: Vacuum packaging the aroma-enhanced common buckwheat whole grain rice and common buckwheat husks separately.

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