A method for improving the taste of rice by high-temperature soaking

Abstract

The present application belongs to the field of rice processing and cooking technology, and particularly relates to a method for improving rice taste by high-temperature soaking, which comprises the following steps: washing rice, soaking the washed rice, and high-temperature soaking, wherein hot water with an initial temperature of 60-80 DEG C is added to the washed rice, and the rice is naturally soaked at room temperature for 20-40 min; removing the rice water extract, adding water with the same mass as the rice water extract to the high-temperature soaked rice; and then performing conventional steaming and braising. The method can improve the taste quality of rice.

Description

Technical Field

[0001] This invention belongs to the field of rice processing and cooking technology, specifically relating to a method for improving the taste and quality of rice based on high-temperature soaking pretreatment. Background Technology

[0002] Rice is a staple food for Chinese residents, and its taste and quality are key indicators determining its commercial value and consumer acceptance. These core dimensions encompass the aroma, texture, elasticity, flavor, and appearance of the cooked rice. Soaking is an essential pre-treatment step before cooking. Proper soaking promotes water absorption and expansion of the rice grains, softens the internal starch structure, and directly affects the final gelatinization and taste of the cooked rice.

[0003] Currently, most home cooking and industrial rice soaking processes use room temperature or low temperature soaking, generally using room temperature water (15℃~25℃) for rinsing and soaking. However, the applicant discovered that this method has the following drawback: at room temperature or low temperature, the thermal movement of water molecules is slow, and water penetration is often limited to the surface of the rice grains. The endosperm core area is not sufficiently hydrated, resulting in incomplete local starch gelatinization and a poorer taste of the cooked rice.

[0004] Traditional methods generally retain the rice water extract for direct steaming, but the applicant found that this method has the following drawbacks: especially under high temperature soaking conditions, a large number of branched / linear starches, proteins and soluble sugar fragments in the water extract will act as "binders" to fill the gaps between rice grains, resulting in rice that is too sticky and lacks elasticity; although the problem is alleviated when soaking at room temperature, it will still affect the taste of the rice.

[0005] To address these issues, while existing technologies have attempted to control water temperature through heating for soaking, these methods often rely on constant-temperature equipment to maintain a specific high-temperature environment, significantly increasing energy consumption and equipment costs. This makes them difficult to promote in everyday household cooking or in large-scale production where complex temperature control equipment is lacking.

[0006] Therefore, how to overcome the limitations of existing technologies and develop a rice pretreatment method that does not require complex constant temperature equipment, is easy to operate, has low cost, and can significantly improve the overall taste score of rice is a technical problem that urgently needs to be solved in the current rice processing and cooking field.

[0007] Invention CN107788346A, entitled "A Method for Effectively Improving the Taste of Rice," discloses the following steps: (1) Harvesting and drying the rice to a moisture content of 14%–15%, and controlling the rice milling rate to 88%–92%; (2) Washing and draining the milled rice, then adding purified water at a water-to-rice weight ratio of 1.2:1; (3) Adding sugar to a rice cooker at a rice-to-sugar weight ratio of 100:1, stirring and soaking for 30–40 minutes; (4) Steaming the soaked rice in a rice cooker for 45–50 minutes, then simmering it for 15 minutes using the residual heat; (5) Opening the lid and turning the steamed rice while maintaining the integrity of the rice grains. This method adds an appropriate amount of sugar during rice soaking, ensuring that the sugar dissolves and penetrates evenly into the rice with the water, thus solving the problem of poor rice taste. The shortcomings of this solution are: First, it relies on the addition of exogenous substances, increasing the cost and difficulty of quality control of raw materials. Second, its equipment adaptability is limited: it relies on a rice cooker to complete the soaking and cooking processes, which has a high equipment threshold and is difficult to directly adapt to ordinary household rice cookers and other common cooking scenarios, thus lacking universality.

[0008] The invention CN119733586A, entitled "A Method for Optimizing the Taste of High-Quality Rice," discloses that the method includes post-harvest processing of rice, hulling, ultrasonic-assisted milling, storage and preservation, and three-stage cooking. It utilizes a grain hulling and milling machine to hull the rice. During the hulling process, magnetization pretreatment weakens the bond between the rice husk and the grain. In subsequent friction hulling, the hulling roller can more easily peel off the husk, reducing mechanical energy loss and time wastage caused by repeated friction or excessive compression, thereby improving overall hulling efficiency. Compared to traditional hulling methods, it further reduces the surface roughness of the rice, enhancing subsequent taste quality. Magnetization treatment alters the internal structure of the rice to some extent, helping to maintain the integrity of the grains and reduce breakage during subsequent processing. Simultaneously, electrostatic adsorption separation and precise air separation effectively remove impurities from the rice. The shortcomings of this solution are as follows: First, it requires significant equipment investment and has high implementation costs: Covering the entire process from post-harvest processing, magnetized hulling, ultrasonic grinding, to three-stage cooking, the solution requires multiple specialized pieces of equipment, resulting in high hardware and maintenance costs and hindering low-cost promotion. Second, its application scenarios are limited, and its universality is poor: the entire process can only be implemented in specialized settings such as rice processing enterprises and large-scale canteens; ordinary households cannot operate it independently, making it difficult to cover the needs of all application scenarios.

[0009] Invention CN111631344A, entitled "A Method for Improving Rice Quality," discloses a method that uses river sand of a specific fineness as an intermediate carrier and employs microwave treatment to penetrate an ethanol-water solution into the interior of newly harvested rice. This promotes the migration of some lipids and proteins from the bran layer into the rice grain, which not only enhances the cell wall strength and intercellular adhesion of starch endosperm cells, reducing the softness of cooked rice, but also avoids grain cracking caused by direct microwave treatment, thus reducing processing losses. However, this method has several drawbacks: First, the process is complex and poses safety and quality control risks: It requires river sand as a carrier combined with microwave treatment and the use of an ethanol-water solution for penetration, making the process cumbersome, difficult to control in terms of quality, and posing a flammable safety hazard, with low operational convenience. Second, its applicability is narrow: the treatment must be completed at the rice processing stage, relying on specialized microwave equipment, and only optimizes the problem of softness in newly harvested rice after cooking. It offers only a single dimension of improvement to the overall taste and quality of rice, resulting in limited overall enhancement. Summary of the Invention

[0010] The problem to be solved by the present invention is to provide a method for improving the taste of rice by soaking at high temperature.

[0011] To address the aforementioned technical problems, this invention provides a method for enhancing the flavor of rice through high-temperature soaking, comprising washing the rice, pre-treating the washed rice by soaking, and then steaming and cooking the rice. The pre-treating by soaking includes the following steps: S1. High-temperature immersion: Add hot water with an initial temperature of 60℃~80℃ to the rinsed rice and let it soak naturally at room temperature for 20~40 minutes (while the water temperature is naturally decreasing) to obtain rice water extract and rice soaked at high temperature. The optimal soaking time is 30 minutes; S2. Remove rice water extract: Remove the rice water extract and add water of the same mass as the rice water extract to the rice that has been soaked at high temperature; Then the product obtained in step S2 is steamed and cooked (conventional steaming and cooking).

[0012] That is, rice that has had its water extract removed and has been replenished with an equal amount of water is then subjected to conventional heating and steaming. After steaming, the rice is then cooked in a conventional simmering process and allowed to cool naturally, resulting in rice with an improved flavor.

[0013] As an improvement to the method of enhancing the flavor of rice through high-temperature soaking according to the present invention, step S1 is as follows: Add hot water with an initial temperature of 60℃~80℃ to the washed rice according to the mass ratio of rice to hot water = 1: (1.2±0.1).

[0014] As a further improvement to the method of improving the taste of rice by high-temperature soaking according to the present invention: the initial temperature of the hot water is 70°C and the soaking time is 30 min.

[0015] As a further improvement to the method of improving the taste of rice by high-temperature soaking in this invention, the washing process is as follows: the rice is washed with water (to remove impurities from the surface of the rice), and the washing is performed 1 to 3 times. Each time the rice is washed, water is added to the rice according to the mass ratio of rice to water = 1: (3 ± 0.5).

[0016] The method for enhancing the flavor of rice through high-temperature soaking according to the present invention has the following technical advantages: 1. This invention promotes the appropriate water absorption, swelling, and pregelatinization of rice starch granules by soaking at a high temperature of 60℃~80℃, laying a good foundation for the formation of gel network during the subsequent cooking process; 2. This invention can significantly reduce the content of leached branched / linear starch, protein and soluble sugar in rice by removing rice water extract, thereby improving the problem of rice stickiness and stickiness, and enhancing the elasticity and taste of rice. 3. The technology of this invention is simple to operate, has no equipment threshold, and can be completed by controlling the initial temperature of water addition and allowing the room temperature to cool down naturally. It is suitable for applications in all scenarios such as homes, canteens, and processing enterprises, and conforms to the principle of economic rationality.

[0017] In summary, the method of the present invention based on high-temperature soaking pretreatment to improve the taste quality can solve the technical problems existing in the prior art, such as incomplete starch gelatinization due to low soaking temperature, sticky texture of rice due to retention of rice water extract during cooking, and reliance on constant temperature equipment for high-temperature soaking. Detailed Implementation

[0018] The room temperature in this invention generally refers to 10~30℃.

[0019] Example 1: A method for enhancing the flavor of rice through high-temperature soaking, comprising the following steps: 1) Washing stage: Accurately weigh 40 g of rice as a sample, put it into an aluminum lunch box, add 120 g of water to wash the rice, stir gently and pour out the rice water, then add 120 g of water and wash it again once. That is, it is washed twice, and each time it is washed, the mass ratio of rice to water is 1:3.

[0020] 2) High-temperature immersion stage: According to the rice-to-water mass ratio of 1:1.2 (w / w), add 48g of hot water with an initial temperature of 60℃~80℃ (see Table 2 for specific water temperatures) to the aluminum box, and let it cool naturally at room temperature for 30 minutes to obtain rice water extract and rice soaked at high temperature.

[0021] 3) Stage of removing rice water extract: After the soaking process is completed, all the rice water extract in the aluminum box is removed, and room temperature water of the same mass as the rice water extract is added back to the rice.

[0022] 4) Steaming and cooking stage: After covering the aluminum container, place it in the rice cooker and steam the rice for 40 minutes. Then turn off the steaming program and let the rice simmer for another 20 minutes without opening the lid. After simmering, remove the aluminum container and let it cool naturally at room temperature for 10 minutes.

[0023] Subsequently, the aluminum box containing the rice was placed in a constant temperature environment of 25°C for later use to prevent the rice from cooling too much and causing starch retrogradation, which would affect the subsequent taste test.

[0024] Sensory Evaluation Verification of Taste Quality: To verify the taste quality of the rice prepared in this embodiment, the following evaluation method was adopted: A professional sensory evaluation team strictly followed the methods specified in the national standard GB / T 15682-2008 "Sensory Evaluation Method for Cooking and Eating Quality of Rice" to conduct sensory evaluation and scoring of rice samples placed in a constant temperature environment of 25℃. The verification results show that compared with the traditional cooking method of soaking at room temperature without removing the water leachate, the rice prepared using the method of this embodiment has a higher overall sensory evaluation score by 2.8 to 5.0 points, and the taste quality improvement effect is significant.

[0025] Experiment 1: A comparative experiment was conducted using the traditional room temperature soaking method and the high-temperature soaking method of the present invention to enhance the taste of rice (Example 1). In this experiment, the four rice samples to be tested were numbered KDML 105 (Thai fragrant rice), ZZY (Zhongzheyou No. 8), LG 31 (Longjing 31), and YG (Japanese Koshihikari).

[0026] Among them, KDML 105, ZZY indica rice, LG 31, and YG are japonica rice.

[0027] Method 1: Room temperature soaking method, conducted according to the experimental steps of GB / T 15682-2008 Sensory Evaluation Method for Cooked and Edible Rice. Specifically, the difference from Example 1 is that in step 2), the 60℃~80℃ hot water is replaced with room temperature clean water, while the water volume remains unchanged, and step 3 is omitted; otherwise, it is the same as Example 1.

[0028] Method 2: The method of improving the taste of rice by high-temperature soaking according to the present invention (Example 1).

[0029] A professional sensory evaluation team conducted a comprehensive sensory evaluation of the rice cooked using the two methods described above (out of 100 points; scoring criteria are shown in Table 1). The average value of the results is shown in Table 2.

[0030] Table 1. Sensory Evaluation Scoring Rules and Record Sheet for Rice

[0031] Table 2. Comparison of overall taste scores of different rice varieties under two soaking methods

[0032] As shown in Table 2, the high-temperature soaking method combined with water change (Method 2) of this invention significantly improved the sensory scores of the four different types of rice compared to traditional soaking (Method 1), with improvements ranging from 2.8 to 5.0 points, due to the high temperature promoting the leaching of redundant soluble substances. Particularly under soaking conditions at 70℃, the overall taste scores of all rice varieties reached their highest levels. This demonstrates that the method of this invention has excellent versatility and significant quality improvement effects on different types of rice.

[0033] Comparative Example 1-1, compared to Example 1, the following changes were made: The initial water temperature for soaking in step 2) was changed from 60℃~80℃ to 30℃, while the soaking time remained unchanged at 30 min. The rest was the same as in Example 1.

[0034] Comparative Examples 1-2, compared to Example 1, are modified as follows: The initial water temperature for soaking in step 2) was changed from 60℃~80℃ to 50℃, while the soaking time remained unchanged at 30 min. The rest was the same as in Example 1.

[0035] Comparative Examples 1-3, compared to Example 1, are modified as follows: The initial water temperature for soaking in step 2) was changed from 60℃~80℃ to 100℃, while the soaking time remained unchanged at 30min. The rest was the same as in Example 1.

[0036] The sensory evaluation results of Comparative Examples 1-1, 1-2, and 1-3, and their comparison with those of Example 1 (70°C of Method 2), are shown in Table 3.

[0037] Table 3. Comparison of the effects of initial water temperature changes on the overall taste score of rice.

[0038] As shown in Table 3, when the initial temperature was only 30℃ (Comparative Example 1-1) and 50℃ (Comparative Example 1-2), the rice grains failed to achieve sufficient hydration due to the low temperature, resulting in incomplete local starch gelatinization and a significantly lower sensory score than in Example 1 (70℃). When the initial temperature reached 100℃ (Comparative Example 1-3), the excessively high water temperature caused excessive gelatinization of the starch on the rice surface, leading to a similar significant decrease in the score. This demonstrates that changing the temperature range of 60℃~80℃ specified in this invention is not feasible in the comparative experiments. Therefore, limiting the initial temperature to 60℃~80℃ is reasonable and crucial in this invention.

[0039] Comparative Example 2: The step of "after the soaking process, completely remove the rice water extract from the aluminum box and replenish the rice with room temperature water of the same mass as the removed water extract" in Example 1 was changed to: not removing the rice water extract, but retaining the rice water extract for direct steaming. The remaining steps were completely the same as in Example 1.

[0040] A professional sensory evaluation team conducted a comprehensive sensory evaluation of the rice cooked using the two methods (out of 100 points), and the average score was taken. See Table 4 for the results.

[0041] Table 4. Comparison of the effects of removing water extract on the overall taste score of rice.

[0042] In this comparative experiment, the overall sensory scores of samples KDML 105, ZZY, LG 31, and YG showed a significant decrease compared to Example 1, with all differences being negative. This indicates that although the high temperature of 60℃~80℃ promotes the leaching of rice water extract, if the rice water extract is not removed, these substances will re-adhere to the surface of the rice grains during the cooking process, leading to a decline in the taste quality. Therefore, the step of "removing rice water extract" in this invention is reasonable and important.

[0043] Comparative Example 3: The amount of hot water used in Example 1 was changed from 48g to 56g or 64g. That is, for indica rice, the amount of water added was 1.6 times the weight of the rice, and for japonica rice, the amount of water added was 1.4 times the weight of the rice. Hot water was added to the aluminum box, and the rest was the same as in Example 1.

[0044] A professional sensory evaluation team conducted a comprehensive sensory evaluation of the rice cooked using the two methods (out of 100 points), and the average value of the results is shown in Table 5.

[0045] Table 5. Comparison of the effects of changes in water addition on the overall taste score of rice

[0046] In this comparative experiment, the overall sensory scores of samples KDML 105, ZZY, LG 31, and YG also showed a significant decrease compared to Example 1, with all differences being negative. When the amount of hot water used for soaking was changed from 48g to 56g or 64g (i.e., the amount of water added to indica rice was 1.6 times the mass of the rice, and the amount of water added to japonica rice was 1.4 times the mass of the rice), the rice grains underwent overhydration, and the endosperm starch swelled excessively. After cooking, the rice became soft and mushy, with increased stickiness and decreased elasticity. The degree of deterioration in the texture of indica rice was more significant than that of japonica rice, ultimately leading to an overall decline in the taste quality. Therefore, the step of "soaking rice in water at a mass ratio of rice to hot water of 1: (1.2 ± 0.1)" in this invention is reasonable and important.

[0047] Finally, it should be noted that the above examples are merely some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for enhancing the flavor of rice through high-temperature soaking, comprising washing the rice, pre-treating the washed rice by soaking, and then steaming and cooking the rice, characterized in that: The soaking pretreatment includes the following steps: S1. High-temperature immersion: Add hot water with an initial temperature of 60℃~80℃ to the rinsed rice and let it soak naturally at room temperature for 20~40 minutes to obtain rice water extract and rice soaked at high temperature. S2. Remove rice water extract: Remove the rice water extract and add water of the same mass as the rice water extract to the rice that has been soaked at high temperature. Then, the product obtained in step S2 is steamed and cooked into rice.

2. The method for enhancing the flavor of rice through high-temperature soaking according to claim 1, characterized in that, Step S1 is as follows: Add hot water with an initial temperature of 60℃~80℃ to the washed rice according to the mass ratio of rice to hot water = 1: (1.2±0.1).

3. The method for enhancing the flavor of rice through high-temperature soaking according to claim 2, characterized in that: The initial temperature of the hot water is 70℃, and the soaking time is 30 minutes.

4. A method for enhancing the flavor of rice through high-temperature soaking according to any one of claims 1 to 3, characterized in that... The washing process is as follows: Wash the rice with water 1 to 3 times. Each time you wash the rice, add water at a mass ratio of rice to water of 1:(3±0.5).

Images