A method for improving the embryo retention rate and quality of germinated rice

Abstract

This invention relates to a method for improving the germ retention rate and quality of germinated rice. Specifically, this invention provides a method for processing dried paddy rice, comprising the steps of: heat-treating the dried paddy rice with superheated steam, and then drying it; wherein the pressure of the superheated steam is ≥2 kg / cm². 2 The temperature of the superheated steam is ≥120℃, and the heat treatment time is less than 90 seconds. The germ rice prepared using the method described herein exhibits improved germ retention rate, reduced broken rice rate, improved oil oxidative stability, and extended shelf life. It also reduces the unhealthy sodium content while increasing the beneficial potassium, iron, and copper content.

Description

Technical Field

[0001] This invention relates to a method for improving the embryo retention rate and quality of germinated rice. Background Technology

[0002] Germinated rice is a type of rice that retains the germ. It requires a high degree of milling precision (2%-7% bran retention) while maintaining a germ retention rate of over 80%. The germ accounts for approximately 3% of the rice's weight, but its nutritional value is about 60%-80% higher than that of ordinary polished rice, especially in B vitamins and unsaturated fatty acids. Therefore, the germ retention rate is a crucial indicator for evaluating germinated rice products. Germinated rice processing typically uses a high-mesh specialized sand roller rice milling machine (this experiment used a Satake 60-mesh germ rice milling machine) to perform multi-stage light milling on brown rice obtained from hulling, thus removing the rice grains and seed coat while retaining as much germ as possible. In contrast, regular rice processing generally uses a low-mesh sand roller rice milling machine (30 or 36 mesh) combined with an iron roller rice milling machine to mill brown rice. Subsequent polishing processes are usually added to make the rice grains more translucent. The final product has a bran retention rate of less than 2% and a very low germ retention rate, generally below 10%. The challenge in processing germ rice lies in balancing the preservation of the germ with the processing precision, especially for long-grain germ rice. Because of its long and thin grains, when the processing precision is increased, the germ retention rate of the product will decrease and the broken rice rate will increase.

[0003] Short-term treatment of long-grain and round-grain dried paddy raw materials with superheated steam has shown that, while achieving the same processing precision, it can significantly improve the germ retention rate of germ rice and reduce the broken rice rate. Furthermore, it improves the oil oxidation stability of the product, extends shelf life, and increases the content of some trace elements. Currently, most methods on the market identify suitable varieties for processing into germ rice through rice variety screening, but no method has been found to improve the germ retention rate of varieties with low germ retention without significantly affecting the product's appearance and quality. Patent CN 114698771 A discloses that "parboiled rice, due to soaking, steaming, and then drying processes, has good grain toughness and a high germ retention rate during the milling stage." This method applies to parboiled rice and does not specify the achievable germ retention rate of the final product. More importantly, the soaking and steaming process is time-consuming, which has a significant negative impact on the product's appearance (color, uniformity, etc.), resulting in uneven brownish-yellow grains and unclear color differences between the germ and endosperm, making it unsuitable for germ rice products. Summary of the Invention

[0004] The present invention aims to propose a processing technology for rice that uses superheated steam for short-term treatment to improve the germ retention rate and quality of germ rice, while achieving the same processing precision.

[0005] The first aspect of this invention provides a method for processing dried rice, the method comprising: heat-treating the dried rice with superheated steam, and then drying it, wherein the pressure of the superheated steam is greater than or equal to 2 kg / cm². 2The temperature of the superheated steam is greater than or equal to 120°C, and the heat treatment time is less than 90 seconds.

[0006] A second aspect of the present invention provides a method for preparing germinated rice, the method comprising: heat-treating dried paddy rice with superheated steam, drying the paddy rice, and then hulling and milling the paddy rice to obtain germinated rice, wherein the pressure of the superheated steam is greater than or equal to 2 kg / cm². 2 The temperature of the superheated steam is greater than or equal to 120°C, and the heat treatment time is less than 90 seconds.

[0007] In one or more embodiments, the pressure of the superheated steam is 2–30 kg / cm². 2 2~25kg / cm 2 5~25kg / cm 2 2~10kg / cm 2 Or 2-5 kg / cm 2 .

[0008] In one or more embodiments, the temperature of the superheated steam is 120–234°C, 120–220°C, 152–220°C, 120–180°C, or 120–152°C.

[0009] In one or more embodiments, the heat treatment time is less than 90 seconds, preferably less than or equal to 80 seconds, for example 10-80 seconds, 10-20 seconds, 20-40 seconds, 50-60 seconds, or 40-80 seconds.

[0010] In one or more embodiments, the heat treatment is performed in a closed environment.

[0011] In one or more embodiments, the moisture content of the dried rice is 12-15%.

[0012] In one or more embodiments, the drying temperature is less than 80°C.

[0013] In one or more embodiments, the drying temperature is 40–60°C, for example 40–50°C or 50–60°C.

[0014] In one or more embodiments, the method further includes the step of cooling the rice grains after heat treatment with the superheated steam before performing the drying process.

[0015] In one or more embodiments, the rice is cooled to 4°C.

[0016] In one or more embodiments, the cooling rate is greater than or equal to 4°C / min.

[0017] In one or more embodiments, the cooling rate is 5–12 °C / min.

[0018] In one or more embodiments, the cooling rate is 5 to 8 °C / min.

[0019] In one or more embodiments, the cooling rate is 10–12 °C / min.

[0020] In one or more embodiments, the cooling time is from 2 minutes to 3 hours.

[0021] In one or more embodiments, the cooling time is 15-30 minutes or 20-30 minutes.

[0022] The third aspect of the present invention provides germ rice or rice products containing germ rice, wherein the method for preparing the germ rice includes the steps of the method described in any embodiment of the first to second aspects herein.

[0023] In one or more embodiments, the germ rice or rice products include cooked rice, rice balls, sushi, rice noodles, rice cakes, rice bread, rice milk beverages, rice steamed buns, rice tofu, and rice sheets.

[0024] The fourth aspect of the present invention provides the use of superheated steam treatment in the preparation of germ rice or rice products containing germ rice.

[0025] In one or more embodiments, optionally, after treating the dried rice with superheated steam, a drying step is also included.

[0026] In one or more embodiments, the rice is dried to its initial moisture content before being subjected to superheated steam treatment.

[0027] In one or more embodiments, the pressure of the superheated steam is greater than or equal to 2 kg / cm². 2 In one or more embodiments, the pressure of the superheated steam is 2–30 kg / cm². 2 .

[0028] In one or more embodiments, the pressure of the superheated steam is 2–25 kg / cm². 2 .

[0029] In one or more embodiments, the pressure of the superheated steam is 5–25 kg / cm². 2 .

[0030] In one or more embodiments, the pressure of the superheated steam is 2–10 kg / cm². 2 .

[0031] In one or more embodiments, the pressure of the superheated steam is 2–5 kg / cm². 2 .

[0032] In one or more embodiments, the temperature of the superheated steam is greater than or equal to 120°C.

[0033] In one or more embodiments, the temperature of the superheated steam is 120–234°C.

[0034] In one or more embodiments, the temperature of the superheated steam is 120–220°C.

[0035] In one or more embodiments, the temperature of the superheated steam is 152–220°C.

[0036] In one or more embodiments, the temperature of the superheated steam is 120–180°C.

[0037] In one or more embodiments, the temperature of the superheated steam is 120–152°C.

[0038] In one or more embodiments, the application includes increasing the germ retention rate of germ rice, and / or reducing the broken rice rate, and / or improving the oxidative stability of germ rice, and / or extending the shelf life of germ rice, and / or reducing the sodium content of germ rice, and / or increasing the content of one or more elements among potassium, iron and copper, wherein the heat treatment time is less than 90 seconds and the drying temperature is less than 80°C. Attached Figure Description

[0039] Figure 1 The rice obtained in Comparative Example 1.

[0040] Figure 2 The rice obtained in Example 1.

[0041] Figure 3 The rice obtained in Comparative Example 2. Detailed Implementation

[0042] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0043] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0044] In this document, the terms “contains,” “includes,” “containing,” and similar terms encompass the meanings of “basically composed of” and “composed of.” For example, when this document discloses “A contains B and C,” “A is basically composed of B and C” and “A is composed of B and C” should be considered as having been disclosed in this document.

[0045] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0046] Unless otherwise specified, percentages refer to mass percentages and proportions refer to mass ratios in this article.

[0047] In this article, the sum of the percentages of all components in the composition is 100%.

[0048] In this article, "dryness" refers to the actual degree of dryness of steam. For example, if steam contains 5% water, its dryness is 95%, or its dryness is 0.95.

[0049] In this article, "superheated steam" refers to steam obtained by further heating dry steam or saturated steam, resulting in an increase in temperature, specific volume, and temperature exceeding the saturation temperature at the corresponding pressure. The dryness fraction of superheated steam is 0.

[0050] In this article, tempering refers to a buffering process (e.g., a gradient buffering process) that allows rice to adapt to sudden changes in drying temperature, ensuring a more uniform exchange of temperature and humidity within the rice grains, thereby reducing the impact of sudden environmental changes on the physicochemical properties and quality of the rice. In the tempering process described in this article, the tempering temperature is lower than the drying temperature.

[0051] In this article, balance refers to the uneven distribution of moisture in the grains after drying, and allowing the grains to stand for a period of time to allow the internal moisture to redistribute evenly.

[0052] In this article, "rice" refers to rice that has not had its husk removed.

[0053] In this article, "brown rice" refers to rice grains after the protective husk (rice husk) has been removed, including the bran layer, endosperm, and germ. The definition of brown rice in this article is based on GB / T 18810-2002 Brown Rice, which states that brown rice is a processed product of paddy rice after hulling, mainly composed of the bran, germ, and endosperm.

[0054] In this article, "rice" is also called white rice or refined white rice, which refers to rice that has been processed to remove the bran layer. Usually, the germ retention rate of rice is less than 10%, and the bran retention rate is less than 2%.

[0055] In this article, "germ rice" refers to rice that retains the germ portion, requiring a processing precision that reaches the appropriate milling level (with a bran retention rate of 2%-7%) while maintaining a germ retention rate of over 80%.

[0056] In this article, the rice variety can be any variety well known in the field, including but not limited to Daohuaxiang No. 2, Deyu 317, Nongjing 306, Yexiang Youlis, Xinfeng No. 6, Jihong No. 6 rice, super rice, Suijing 18, Longjing 31, Jihong 6, Yanfeng 47, Songjing 16, Longdun 1614, Longyang 16, Songjing 29, Zhongkefa 5, Zhongkefa 804, Tianlong 619, etc.; Daohuaxiang No. 2 or Jihong No. 6 are preferred.

[0057] In this document, when describing embodiments or examples, it should be understood that it is not intended to limit the invention to those embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein are covered within the scope defined by the claims.

[0058] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0059] Directly drying paddy rice does not significantly extend shelf life or improve rice quality, such as increasing mineral content. However, the inventors have discovered that short-term superheated steam treatment of paddy rice can improve the germ retention rate and quality of germinated rice. Germinated rice prepared using this process exhibits increased germ retention, reduced broken rice rate, improved oil oxidation stability, extended shelf life, reduced unhealthy sodium content, and increased beneficial potassium, iron, and copper content. This invention thus completes the present invention.

[0060] Germinated rice and its preparation method

[0061] This invention first provides a method for processing dried rice, which includes the steps of heat-treating the dried rice with superheated steam and then drying the rice, wherein the pressure of the superheated steam is ≥2 kg / cm². 2 The temperature of the superheated steam is ≥120°C, and the heat treatment time is less than 90 seconds, preferably less than or equal to 80 seconds. In some embodiments, the heat treatment is carried out in a closed environment.

[0062] In this article, "superheated steam" refers to steam whose temperature is higher than the saturated steam temperature at a certain pressure. For example, at 1 atmosphere (approximately 1 MPa = 10 kg / cm²), superheated steam... 2At this temperature, water boils at 100℃, while superheated steam can reach temperatures of 120℃, 150℃, 200℃, or even higher. The temperature of superheated steam generally varies depending on the pressure, which ranges from 2 to 5 kg / cm². 2 The temperature of superheated steam is typically 120–152℃, and the pressure is 15–25 kg / cm². 2 The temperature of superheated steam is typically 200–220℃, and the pressure is 30–40 kg / cm³. 2 The temperature of superheated steam is typically 234–250℃, and the pressure is 80–100 kg / cm³. 2 The temperature of superheated steam is typically 295–311℃, and the pressure is 100–220 kg / cm³. 2 The temperature of superheated steam is typically 311–375°C.

[0063] In the method described herein, dried rice grains are placed in a sealed container, and superheated steam is introduced. Superheated steam typically has extremely strong penetrating power, and stirring is generally unnecessary during the treatment process. The amount of rice grains can be selected based on the size of the sealed container, ensuring that each grain is steam-treated. The temperature and pressure of the superheated steam can be selected based on the available steam supply equipment, such as a Sodick superheated steam generator from Japan. In an exemplary embodiment, the pressure of the superheated steam in the method of this invention is greater than or equal to 2 kg / cm². 2 For example, 2-30 kg / cm 2 2~25kg / cm 2 5~25kg / cm 2 2~10kg / cm 2 Or 2-5 kg / cm 2 The temperature should be greater than or equal to 120℃, for example, 120~234℃, 120~220℃, 152~220℃, 120~180℃, or 120~152℃. The superheated steam heat treatment time should be as short as possible, usually 10~80 seconds, for example, 10~20 seconds, 20~40 seconds, 50~60 seconds, or 40~80 seconds.

[0064] After steam treatment, a drying step is required to prevent the rice from becoming damp and moldy. Typically, the drying temperature is below 80℃, and can be 40–60℃, for example, 40–50℃ or 50–60℃. In the method described in this article, there is no particular limitation on the drying time for germ rice; drying to the initial moisture content before steam treatment is sufficient. The moisture content of the dried rice is generally 12–15% or 14–15%, usually less than or equal to 14.5%. After soaking for 3–5 hours, the moisture content of the dried rice usually increases to 40–50%.

[0065] After drying, conventional hulling and milling steps can be used to separate the dried paddy husks (hulls) from the brown rice, and mill the brown rice to obtain germinated rice. The method of this invention does not have particular limitations on the hulling and milling steps; conventional hulling and milling machines, such as the Satake rice hulling machine and Satake rice milling machine from Japan, can be used. Typically, abrasive rollers are used for milling to obtain germinated rice. The mesh size, rotation speed, and milling time of the abrasive rollers can be selected according to actual conditions, such as the type of rice milling machine and / or the variety of rice. For example, the mesh size of the abrasive rollers can be 30, 36, or 60, preferably 60. The rotation speed of the abrasive rollers can be 800–900 r / min, for example, 850–900 r / min. The milling time can also be selected according to the required processing precision of the germinated rice, and can be 10–20 min or 8–10 min.

[0066] In some embodiments, the method further includes a step of cooling the dried rice after heat treatment with superheated steam before proceeding with the drying process. In a preferred embodiment, the cooling rate is greater than or equal to 4°C / min, and the specific cooling time is selected based on the amount of rice, ranging from 2 minutes to 3 hours. Generally, cooling the rice to 4°C is sufficient. Conventional cooling methods can be used, such as liquid nitrogen rapid cooling, with a cooling rate of 5–12°C / min, 5–8°C / min, or 10–12°C / min, and a cooling time of 2–3 minutes. Alternatively, the dried rice can be directly placed in a 0–4°C cold storage, with a cooling time of 1–5 hours or 2–3 hours, preferably 15–30 minutes or 20–30 minutes.

[0067] Therefore, in some embodiments, this document also provides a method for preparing germinated rice, the method comprising: heat-treating paddy rice with superheated steam, drying the paddy rice, and then hulling and milling it to obtain germinated rice. The heat treatment and drying steps are as described in any embodiment of this document. In some embodiments, this document also provides a method for improving the germ retention rate of germinated rice, reducing the broken rice rate of germinated rice, improving the oxidative stability of germinated rice, and / or extending the shelf life of germinated rice. The heat treatment and drying steps are as described in any embodiment of this document.

[0068] The germ rice prepared using the method described in this paper has an increased germ retention rate, a decreased broken rice rate, improved oil oxidation stability, and an extended shelf life. It also has a lower sodium content, which is detrimental to health, and a higher content of beneficial potassium, iron, and copper.

[0069] The present invention also provides germ rice having one or more of the following characteristics: whiteness of 35-40%, preferably 35-38%; bran retention of 5.5-6.5%, preferably 5.9-6.5% or 5.9-6.3%; germ retention rate of 90-97%, preferably 92-95% or 93-97%; oxidative stability of 12-13.5h, preferably 12.3-12.7h or 12.4-12.7h; sodium content of less than or equal to 6.00 mg / kg, preferably less than or equal to 7.90 mg / kg or preferably less than or equal to 5.50 mg / kg; potassium content of greater than or equal to 1350 mg / kg, preferably greater than or equal to 1420 mg / kg, preferably greater than or equal to 1500 mg / kg or 1600 mg / kg; iron content of greater than or equal to 7.30 mg / kg or greater than or equal to 7.50 mg / kg; and copper content of greater than or equal to 1.85 mg / kg or greater than or equal to 1.90 mg / kg.

[0070] In some embodiments, the germ rice described herein contains 5.00–5.50 mg / kg of sodium, preferably 5.03–2.34 mg / kg, 5.02–5.34 mg / kg, or 6.20–6.40 mg / kg. In some embodiments, the germ rice described herein contains 1350–1450 mg / kg, 1520–1650 mg / kg, or 1550–1600 mg / kg of potassium. In some embodiments, the germ rice described herein contains 7.30–7.50 mg / kg, 7.40–7.80 mg / kg, or 7.50–7.60 mg / kg of iron. In some embodiments, the germ rice described herein contains 1.85–1.93 mg / kg or 1.88–1.90 mg / kg of copper.

[0071] In some embodiments, the germ rice of the present invention is prepared by the method described in any of the embodiments herein.

[0072] Rice products containing germ rice and their applications

[0073] The present invention also provides germ rice or rice products containing germ rice as described in any embodiment herein, including cooked rice obtained by cooking germ rice or rice products, or food containing rice, such as rice balls, sushi, rice noodles, rice cakes, rice bread, rice milk beverages, rice steamed buns, rice tofu, and rice sheets.

[0074] In some embodiments, this document also provides a method for preparing germinated rice or rice products containing said germinated rice, the method comprising the steps of the method for preparing germinated rice as described in any embodiment herein.

[0075] This invention also provides the application of the method described in any embodiment herein in the preparation of germinated rice or rice products containing such germinated rice, the application including increasing the germ retention rate of the germinated rice, and / or reducing the broken rice rate, and / or improving the oxidative stability of the germinated rice, and / or extending the shelf life of the germinated rice, and / or reducing the sodium content of the germinated rice, and / or increasing the content of one or more elements selected from potassium, iron, and copper.

[0076] The present invention will be further described below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and are not intended to limit the scope of the invention. Unless otherwise stated, the methods and reagents used in the embodiments are conventional methods and reagents in the art.

[0077] Testing indicators:

[0078] (1) Embryo retention rate: According to the standard GB / T 42227-2022 Embryo Retention Rice, about 10g of whole rice grains are taken and half-embryo grains, flat-embryo grains and full-embryo grains are picked out and summed to obtain the embryo retention grains, and then the embryo retention rate is calculated.

[0079] (2) Processing precision: According to the characterization of husk retention in "GB / T 1354-2018 Rice", the specific testing method is in accordance with "GB / T 5502-2018 Grain and Oil Inspection Rice Processing Precision Inspection".

[0080] (3) Broken rice rate: The broken rice rate is calculated according to GB / T 1354-2018 Rice.

[0081] (4) Whiteness: The whiteness was measured using the Satake MM1D rice whiteness meter from Japan.

[0082] (5) Oxidative stability: The oxidative stability of germ rice depends on the oil in it. Therefore, the oxidative stability of the product is characterized by the oxidation induction time using the OXITEST oil oxidation analyzer. 20g of sample was ground into powder using a small steel mill and then reacted with pure oxygen at 5 bar and 100℃ to obtain the product oxidation induction time.

[0083] (6) Mineral content: The content of each mineral element was determined according to GB 5009.268—2016 Determination of multiple elements in food.

[0084] (7) Rice moisture: The moisture content shall be determined in accordance with the "GB 5009.3-2016 National Food Safety Standard - Determination of Moisture in Food".

[0085] Unless otherwise specified, the initial moisture content of the dry rice samples of long-grain Daohuaxiang and short-grain Jihong 6 in the examples and comparative examples in this article is 14%-15%. Daohuaxiang 2 rice was sourced from Yihai Wuchang Factory, and Jihong 6 rice was sourced from Yihai Baicheng Factory.

[0086] Experimental equipment:

[0087] (1) Sample preparation equipment: Japanese Sodick superheated steam generator, electric thermostatic drying oven DHG-9240A, Satake rice huller THU35C, Satake germ rice maker TM05C.

[0088] (2) Testing equipment: Beijing Dongfu Rice Appearance Quality Analyzer, Satake Rice Whiteness Analyzer MM1D, Oil Oxidation Analyzer OXITEST, Inductively Coupled Plasma Mass Spectrometer (ICP-MS).

[0089] Example 1

[0090] 3kg / cm² in an enclosed space 2 Under pressure, 50g of dried rice (long-grain rice) was heat-treated with superheated steam at 140℃ for 20 and 40 seconds respectively, and then dried in an oven at 50℃ with hot air until the initial moisture content of the rice was reduced. The rice husks were removed using a rice huller, and the rice was then milled in a Satake 60-mesh sand roller mill at 855r / min for 14 minutes to obtain germ rice.

[0091] 3kg / cm² in an enclosed space 2 Under pressure, 50g of Jihong No. 6 (short-grain rice) dry paddy was heat-treated with superheated steam at 140℃ for 20 and 40 seconds respectively, and then dried in an oven at 50℃ with hot air until the initial moisture content of the paddy was reduced. The husks were removed using a rice huller, and the rice was milled in a Satake 60-mesh sand roller mill at 855r / min for 14 minutes to obtain germ rice.

[0092] Example 2

[0093] 2kg / cm² in an enclosed space 2 Under pressure, 100g of Jihong No. 6 (short-grain rice) dry paddy was heat-treated with superheated steam at 120℃ for 80 seconds, and then dried in an oven at 60℃ with hot air until the initial moisture content of the paddy was reduced. The husks were removed using a rice huller, and the rice was milled in a Satake 60-mesh sand roller mill at 855r / min for 14min to obtain germ rice.

[0094] Example 3

[0095] 5kg / cm² in a closed space 2 Under pressure, 100g of Jihong No. 6 (short-grain rice) dry paddy was heat-treated with superheated steam at 150℃ for 10 seconds, and then dried in an oven at 40℃ with hot air until the initial moisture content of the paddy was reduced. The husks were removed using a rice huller, and the rice was milled in a Satake 60-mesh sand roller mill at 855r / min for 14min to obtain germ rice.

[0096] Example 4

[0097] 3kg / cm² in an enclosed space 2Under pressure, 100g of Daohuaxiang and Jihong No. 6 rice were heat-treated with superheated steam at 140℃ for 20 seconds, then rapidly cooled in a 4℃ cold storage for 2 hours, and finally dried in a 50℃ hot air oven to their initial moisture content. The rice husks were removed using a rice huller, and the rice was then milled in a Satake 60-mesh sand roller mill at 855r / min for 14 minutes to obtain germ rice.

[0098] Example 5

[0099] 3kg / cm² in an enclosed space 2 Under pressure, 100g of Jihong No. 6 rice was heat-treated with superheated steam at 140℃ for 20 seconds, then rapidly cooled to 4℃ with liquid nitrogen for 2 minutes (temperature drop rate approximately 12℃ / min), and then dried in an oven at 50℃ with hot air until the initial moisture content of the rice was reduced. The rice husks were removed using a rice huller, and the rice was then milled for 14 minutes at 855 rpm using a Satake 60-mesh sand roller rice milling machine to obtain germ rice.

[0100] Comparative Example 1

[0101] The raw materials are Daohuaxiang and Jihong No. 6 dry rice, which are directly hulled and milled into germ rice without any processing. The rice husks are removed using a rice huller, and the rice is milled for 14 minutes at 855 r / min using a Satake 60 mesh sand roller mill to obtain germ rice.

[0102] Comparative Example 2

[0103] 2kg / cm² in an enclosed space 2 Under pressure, 300g of Daohuaxiang and Jihong No. 6 rice were heat-treated with superheated steam at 120℃ for 90 seconds, and then dried with hot air in an oven at 60℃ until the initial moisture content of the rice was reduced. The rice husks were removed using a rice huller, and the rice was milled in a Satake 60-mesh sand roller mill at 855r / min for 14 minutes to obtain germ rice.

[0104] Comparative Example 3

[0105] 1kg / cm² in a closed space 2 Under pressure, 300g of Daohuaxiang and Jihong No. 6 rice were heat-treated with superheated steam at 100℃ for 80 seconds, and then dried with hot air in an oven at 60℃ until the initial moisture content of the rice was reduced. The rice husks were removed using a rice huller, and the rice was then milled in a Satake 60-mesh sand roller mill at 855r / min for 14 minutes to obtain germ rice.

[0106] Comparative Example 4

[0107] 3kg / cm² in an enclosed space 2Under pressure, 300g of dried rice varieties of Daohuaxiang (long-grain rice) and Jihong No. 6 (short-grain rice) were heat-treated with superheated steam at 140℃ for 20 seconds, and then dried in an oven at 80℃ with hot air until the initial moisture content of the rice was reduced. The rice husks were removed using a rice huller, and the rice was then milled in a Satake 60-mesh sand roller mill at 855r / min for 14min to obtain germ rice.

[0108] Comparative Example 5

[0109] Soak 300g of Jihong No. 6 rice in clean water for 10 minutes, then soak it in 45℃ warm water for 4 hours (increasing the moisture content to about 40-50%), and then press it under high pressure (about 2kg / cm). 2 Steam at 120-125℃ for 10 minutes in a steaming pot, then dry with hot air at 55-60℃ for 1 hour, temper for 3 hours, and then dry with hot air at 40℃ until the moisture content is about 14%. Remove the rice husks with a rice huller, and then grind the rice with a Satake 60-mesh sand roller mill at 855 r / min for 14 minutes to obtain germ rice.

[0110] Comparative Example 6

[0111] After soaking 300g of Jihong No. 6 rice at room temperature for 2 hours, it was then subjected to a process at 3kg / cm². 2 Under pressure, the rice was heat-treated with superheated steam at 140°C for 20, 40, and 60 seconds respectively, and then dried with hot air at 50°C in an oven until the initial moisture content of the rice was reduced. The rice husks were removed using a rice huller, and the rice was then milled in a Satake 60-mesh sand roller mill at 855 r / min for 14 minutes to obtain germ rice.

[0112] Comparative Example 7

[0113] 300g of Daohuaxiang and Jihong No. 6 rice (moisture content 14.8%) were stirred separately at 35℃ for 40 minutes. The rice husks were removed using a rice huller, and the rice was milled for 14 minutes at 855r / min using a Satake 60-mesh sand roller rice miller to obtain germ rice.

[0114] Comparative Example 8

[0115] 300g of Daohuaxiang brown rice and Jihong No. 6 brown rice were separated without soaking and cooked at 3kg / cm². 2 Under pressure, the rice was heat-treated with superheated steam at 140°C for 20 seconds, and then dried in an oven at 50°C with hot air until the initial moisture content of the brown rice was reduced. Germinated rice was obtained by milling the rice using a Satake 60-mesh abrasive roller mill at 855 rpm for 14 minutes.

[0116] 300g of Daohuaxiang brown rice and Jihong No. 6 brown rice were soaked separately at room temperature for 2 hours, and then... (The sentence is incomplete and ends abruptly.) 2Under pressure, the rice was treated with superheated steam at 140°C for 20 seconds, and then dried in an oven at 50°C with hot air until the initial moisture content of the brown rice was reduced. Germinated rice was obtained by milling the rice using a Satake 60-mesh abrasive roller mill at 855 rpm for 14 minutes.

[0117] The parameters of the germ rice in each embodiment and comparative example were tested, and the results are as follows:

[0118] Table 1 Rice Variety 1 – Jihong No. 6 (Short Grain Rice)

[0119]

[0120]

[0121] *Note: The short-grain rice sample in Comparative Example 3 became severely dark in color after prolonged soaking and cooking. The endosperm could not be stained with eosin Y-methylene blue staining solution in GB / T 5502-2018 Grain and Oil Inspection: Rice Processing Precision Inspection. Therefore, the husk retention data could not be obtained through image acquisition.

[0122] Table 2 Rice Type 2 – Daohuaxiang (Long Grain Rice)

[0123]

[0124] As shown in the table above, the pressure should not be less than 2 kg / cm². 2 Although short-term treatment with superheated steam at a temperature not lower than 120℃ (as shown in the table above, 10-80 seconds) had some impact on the whiteness of the dried rice, the difference in appearance between the sample and the untreated sample (Comparative Example 1) was not significant to the naked eye. The rice grains remained relatively white (whiteness measured by a whiteness meter in Example 1 > 35%), and the overall appearance was acceptable according to sensory evaluation (e.g., ...). Figure 2 When the processing time exceeds 80 seconds (as in Comparative Example 2), the rice grains appear yellowish (whiteness measured by a whiteness meter <35%), and the overall appearance is unacceptable according to sensory evaluation. For short-time heat treatment of wet rice, a whiteness of only 20 seconds is acceptable (approximately 35%). Using the soaking, cooking, and drying process described in patent CN 114698771 A (Comparative Example 5), the whiteness is only 17.8%, and the color is brownish-yellow (as in Comparative Example 5). Figure 3 The endosperm color is similar to the germ color, making identification difficult and preventing accurate calculation of the embryo retention rate using national standard methods. When using materials with a density below 2 kg / cm²... 2Treating dried rice with superheated steam at temperatures below 120℃ (as in Comparative Example 3) did not significantly improve the germ retention rate or oil oxidation stability. Treating rice at even lower temperatures (Comparative Example 7) had no noticeable effect on germ retention rate or oil oxidation stability. Furthermore, excessively high drying temperatures led to an increase in the broken rice rate of the final product (Comparative Example 4). Therefore, after superheated steam treatment, rice should be dried with hot air at a temperature not exceeding 60℃. The broken rice rate of dried rice did not change significantly after superheated steam treatment because the broken rice rate of short-grain rice is already extremely low without treatment; however, the broken rice rate of wet rice increased significantly after treatment. If brown rice is used as raw material and treated with hot steam, the rice grains, without the protection of the husk, gel and stick together when heated, making them difficult to separate. This results in difficult subsequent drying, with the rice clumping together and poor quality.

[0125] It is evident that for short-grain rice like Jihong No. 6, under the same processing precision (characterized by bran retention), short-time hot steam treatment improves the germ retention rate, enhances oil oxidation stability, and increases the content of beneficial minerals. Furthermore, heat treatment of rice has a certain impact on the whiteness of the final product; as the treatment time increases, the whiteness continuously decreases, and for the same treatment time, the whiteness of wet rice is lower than that of dry rice.

[0126] For long-grain rice like Daohuaxiang, under the same processing precision (characterized by bran retention), short-term hot steam treatment significantly increases the germ retention rate, reduces the broken rice rate, and improves oil oxidation stability. Similarly, soaking paddy rice followed by heat treatment leads to decreased whiteness and increased broken rice rate, while excessively long treatment times cause the rice grains to turn yellow. Low-temperature treatment of paddy rice has no visible effect on indicators such as germ retention rate and oil oxidation stability. Therefore, this patent uses short-term superheated steam treatment of dry paddy rice, which improves the germ retention rate while ensuring the appearance quality of the final germ rice product.

[0127] In summary, to ensure the appearance quality of germ rice, it is not recommended to use a soaking process, and the heat treatment time should not be too long.

Claims

1. A method for processing dried rice, characterized in that, The method includes the steps of: heat-treating dried rice with superheated steam, followed by drying; wherein the pressure of the superheated steam is ≥2 kg / cm². 2 The temperature of the superheated steam is ≥120℃, and the heat treatment time is less than 90 seconds.

2. A method for preparing germinated rice, characterized in that, The method includes the steps of: heat-treating dried paddy rice with superheated steam, drying the paddy rice, and then hulling and milling it to obtain germinated rice; wherein the pressure of the superheated steam is greater than or equal to 2 kg / cm². 2 The temperature of the superheated steam is greater than or equal to 120°C, and the heat treatment time is less than 90 seconds.

3. The method as described in claim 1 or 2, characterized in that, The pressure of the superheated steam is 2–30 kg / cm². 2 2~25kg / cm 2 5~25kg / cm 2 2~10kg / cm 2 Or 2-5 kg / cm 2 , and / or The temperature of the superheated steam is 120–234°C, 120–220°C, 152–220°C, 120–180°C, or 120–152°C, and / or The heat treatment time is less than 90 seconds, preferably less than or equal to 80 seconds, for example 10-80 seconds, 10-20 seconds, 20-40 seconds, 50-60 seconds, 40-80 seconds, and / or The heat treatment is carried out in a closed environment.

4. The method according to any one of claims 1-3, characterized in that, The moisture content of the dried rice is 12-15%, and / or The drying temperature is less than 80°C, preferably 40-60°C, for example 40-50°C or 50-60°C.

5. The method according to any one of claims 1-4, characterized in that, The method also includes the steps of cooling the rice grains after heat treatment with the superheated steam before proceeding with the drying process. Preferably, the rice is cooled to 4°C.

6. The method as described in claim 5, characterized in that, The cooling rate is greater than or equal to 4°C / min, preferably 5–12°C / min, 5–8°C / min, or 10–12°C / min, and / or The cooling time is from 2 minutes to 3 hours, preferably 15 to 30 minutes or 20 to 30 minutes.

7. A type of germinated rice or a rice product containing said germinated rice, characterized in that, The method for preparing germinated rice includes the steps of the method as described in any one of claims 1-6.

8. The germ rice or rice product containing the germ rice as described in claim 7, characterized in that, The germ rice or rice products include cooked rice, rice balls, sushi, rice noodles, rice cakes, rice bread, rice milk beverages, rice steamed buns, rice tofu, and rice sheets.

9. Application of superheated steam treatment in the preparation of germ rice or rice products containing germ rice. Optionally, after superheated steam treatment, a drying step is further included, preferably drying to the initial moisture content of the dried rice before superheated steam treatment. Preferably, the pressure of the superheated steam is greater than or equal to 2 kg / cm². 2 For example, 2-30 kg / cm 2 2~25kg / cm 2 5~25kg / cm 2 2~10kg / cm 2 Or 2-5 kg / cm 2 , Preferably, the temperature of the superheated steam is greater than or equal to 120°C, for example, 120–234°C, 120–220°C, 152–220°C, 120–180°C, or 120–152°C.

10. The application as described in claim 9, characterized in that, The applications include increasing the germ retention rate of germ rice, and / or reducing the broken rice rate, and / or improving the oxidative stability of germ rice, and / or extending the shelf life of germ rice, and / or reducing the sodium content of germ rice, and / or increasing the content of one or more elements among potassium, iron and copper.

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