Low-viscosity cassava recombinant rice and preparation method thereof

Abstract

The invention discloses low-viscosity cassava recombinant rice and a preparation method thereof, and belongs to the technical field of food processing. The method comprises the following steps: taking whole cassava flour as a main raw material, mixing with monoglyceride, humidifying, and carrying out extrusion forming to obtain a rice grain matrix; then, an O / W emulsion coating solution prepared from sodium alginate, glycerin, water, edible oil and an emulsifier is adopted to conduct primary spraying on the rice grain matrix, then a calcium salt solution is adopted to conduct secondary spraying, cross-linking curing, and air drying is conducted to obtain a finished product. Edible oil drops are wrapped through a sodium alginate-calcium ion cross-linking technology, a compact hydrophobic gel film is constructed on the surfaces of rice grains, moisture permeation is effectively blocked in the cooking process, the cooking adhesive force of the cassava recombined rice subjected to coating treatment is reduced by 95.7%, the technical problems that the cassava recombined rice is extremely high in viscosity and prone to being bonded into blocks are solved, and the quality of the cassava recombined rice is improved. The obtained product is clear in particle and appropriate in taste after being cooked, and a new way is provided for efficient staple food utilization of cassava.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of food processing technology, and in particular to a low-viscosity cassava restructured rice with a sodium alginate emulsion coating on the surface and a preparation method thereof. BACKGROUND

[0002] The restructured rice technology significantly improves the economic value of raw materials (cost reduction of 30-40%) by integrating low-cost grain resources (such as broken rice, indica rice, and aged grain), and relies on moisture control (≤12%) and extrusion sterilization process to extend the shelf life to 24 months, meeting the strategic reserve demand. At the same time, the technology realizes precise nutrition fortification: basic nutrients such as minerals (iron, zinc), vitamin B family, or functional ingredients such as cassava dietary fiber, resistant starch (>20%), and plant protein can be added to customize the health needs of diabetic and obese populations. Moreover, the raw material inclusiveness also supports the integration of diverse components such as coarse grains and insect proteins, to promote the innovation of staple foods through industrial production, with the triple social values of resource-efficient utilization, nutrition upgrading, and emergency protection.

[0003] Cassava, also known as manioc or manihot, is a perennial shrub and is commonly known as one of the three major potato crops in the world, along with sweet potato and potato. Cassava is widely cultivated due to its strong environmental adaptability, simple technology, few pests and diseases, and long growth cycle, which makes it easy to manage. Currently, the processing of cassava mainly focuses on industrial development and utilization, such as the production of starch, alcohol, and citric acid. In terms of edible use, the processing degree of cassava is low, and it is mainly consumed directly. This status limits the large-scale application of cassava in the food industry, preventing it from fully realizing its edible value.

[0004] Cassava flour can well maintain its nutrition and flavor, and can be widely used in the food industry as a raw material for food processing. However, due to its high viscosity, it is prone to sticking, and therefore must be blended with other high-priced grains to reduce its viscosity. For example, patent document CN107874110A discloses a cassava rice, in which the mass fraction of cassava starch in the raw materials is only 1-30 parts, blended with early indica rice flour, glutinous rice, millet, and Thai fragrant rice. As the proportion of cassava increases, the viscosity of the restructured rice also increases, so the proportion of cassava in the cassava restructured rice generally does not exceed 30%. In a strict sense, it is not suitable to be called cassava restructured rice.

[0005] In addition, physical methods (such as heat treatment and shear treatment), chemical modification methods (such as oxidation treatment, acid treatment, and enzyme treatment) can be used to reduce the viscosity of starch. For example, patent document CN103554281A discloses a method of first preparing esterified starch by reacting cassava starch with an esterifying agent in the presence of a catalyst, and then preparing low-viscosity cassava composite modified starch by irradiation. However, chemical modification introduces non-edible chemical reagents, which is not conducive to application in the field of food processing.

[0006] Therefore, it is a technical problem for those skilled in the art to develop a cassava restructured rice which meets the food safety requirements and takes cassava powder as the main raw material (≥95%). SUMMARY

[0007] The present application aims to provide a cassava instant rice which takes cassava powder as the main raw material (≥95%), and has good taste, clear particles and low viscosity after cooking.

[0008] To achieve the above-mentioned purpose, the present application adopts the following technical solutions: The present application provides a preparation method of low-viscosity cassava restructured rice, comprising the following steps: (1) mixing cassava powder and monoglyceride at a mass ratio of 95-99:1-5, adding water and stirring to obtain a mixture, and controlling the water content at 28-40%; after gelatinization of the mixture, cutting and granulating to obtain a rice particle matrix; (2) heating and mixing sodium alginate, glycerol and water to obtain an aqueous phase, heating and mixing edible oil and emulsifier to obtain an oil phase, adding the oil phase to the aqueous phase to emulsify and obtain an emulsion coating liquid; the mass ratio of sodium alginate, glycerol, edible oil, emulsifier and water is 0.25-1.5:0.25-1.0:10-30:0.5-1.5:60-89; (3) dissolving calcium salt in water to obtain a calcium salt solution with a concentration of 10-20 g / L; (4) uniformly spraying the emulsion coating liquid on the surface of the rice particle matrix, then uniformly spraying the calcium salt solution, and then air-drying at a temperature of 30-70°C to obtain the low-viscosity cassava restructured rice.

[0009] In the present application, the cassava powder is derived from edible cassava tubers and has been processed to remove toxicity by peeling, etc.

[0010] In the present application, the O / W emulsion coating of sodium alginate-edible oil and the calcium ion cross-linking solidification technology are applied to the surface treatment of cassava restructured rice, and at the same time, the edible oil droplet molecules are locked on the surface of the restructured rice to construct a strong hydrophobic protective film, which fundamentally physically blocks the contact between water and starch during cooking, effectively blocks the penetration of water, reduces the cooking adhesion, and realizes the preparation of restructured rice with cassava powder as the only main food raw material. The above method discards the previous technical path of compounding other cereals such as rice and millet or using chemically modified starch, and breaks through the traditional cognition that the viscosity cannot be controlled when the cassava content exceeds 30%.

[0011] Specifically, in step (1), the cassava powder is mixed with monoglyceride, humidified, and extruded by a double screw to obtain a rice particle matrix.

[0012] A small amount of monoglyceride can improve the texture and taste of rice while playing a role in auxiliary dispersion and lubrication during extrusion, thus making the extruded rice surface smoother.

[0013] The mixture is controlled at a water content of 28-40% to obtain rice with a compact and uniform structure and a smooth surface. It is found that a too low water content during extrusion can result in a too low starch gelatinization degree, and the product can have problems such as internal raw starch, die blockage, and easy breakage during cutting. A too high water content can result in a too high steam pressure due to the rapid evaporation of excessive water during extrusion, thus leading to excessive puffing of the rice, the generation of large cavities, and the production of rice like puffed food rather than compact rice structure.

[0014] Preferably, the cassava powder and the monoglyceride are mixed at a mass ratio of 97-99:1-3, and the mixture is controlled at a water content of 30-40%.

[0015] In the present application, the rice matrix is prepared by extrusion molding. Specifically, the mixed material is fed into the feeding slot of the extruder, and the material passes through the following zones in sequence: Zone 1, mixing and preheating: water absorption and softening to form uniform material; Zone 2, extrusion and conveying: compression and preheating to accumulate energy; Zone 3, pre-gelatinization: expansion of material particles and melting of crystals to start gelatinization; Zone 4, gelatinization and shearing: complete gelatinization and shearing degradation of the material to form a homogeneous melt; and Zone 5, high-pressure melting: the internal structure of the high-pressure melted rice begins to form. Finally, the material is extruded from the furnace, passes through the die, and is cut into shape by a high-speed rotating (about 1000 rpm) cutter.

[0016] Preferably, the feeding speed is 30-40 kg / h, the temperature in Zone 1 is 40-60°C, the temperature in Zone 2 is 50-70°C, the temperature in Zone 3 is 70-90°C, the temperature in Zone 4 is 75-95°C, the temperature in Zone 5 is 60-80°C, and the pressure is 4-7 MPa. The cutting speed is always maintained at 1000 rpm to ensure consistent cutting and molding. The cassava restructured rice prepared by the present application has an ellipsoidal shape with a size of (5.0 ± 0.2) mm x (3.0 ± 0.2) mm and an aspect ratio of about 1.67. The equivalent volume diameter is about 3.56 mm.

[0017] More preferably, the feeding speed is 30 kg / h, the temperature in Zone 1 is 50°C, the temperature in Zone 2 is 60°C, the temperature in Zone 3 is 80°C, the temperature in Zone 4 is 90°C, the temperature in Zone 5 is 65°C, and the pressure is 5.6 MPa.

[0018] In step (2), an O / W emulsion coating solution is prepared using sodium alginate, glycerol, water, edible oil, and an emulsifier. Sodium alginate provides a polysaccharide skeleton structure, which encapsulates the edible oil to form a hydrophobic coating on the surface of the rice matrix, and glycerol acts as a plasticizer for the film.

[0019] Preferably, the preparation method of the emulsion coating liquid includes: adding sodium alginate to water at 50-60°C, stirring continuously until completely dissolved, then adding glycerol and stirring evenly to obtain an aqueous phase; mixing edible oil and emulsifier, stirring at 50-60°C to dissolve the emulsifier in the edible oil to obtain an oil phase; and adding the oil phase to the aqueous phase for emulsification to obtain the emulsion coating liquid.

[0020] The emulsification method includes: slowly adding the oil phase to the aqueous phase under high-speed stirring for 3-5 minutes until a uniform, stable, milky white oil-in-water (O / W) emulsion is formed.

[0021] As a preferred embodiment, the mass ratio of sodium alginate, glycerin, edible oil, emulsifier, and water is 0.25-1.0:0.25-0.75:20-30:0.5-1.5:67-79.

[0022] More preferably, the mass ratio of sodium alginate, glycerin, edible oil, emulsifier, and water is 1.0:0.5:20:1.0:77.5.

[0023] Preferably, the edible oil is coconut oil, palm oil, butter, olive oil, rapeseed oil, peanut oil, soybean oil, corn oil, or sunflower oil.

[0024] More preferably, the edible oil is coconut oil.

[0025] Preferably, the emulsifier is monoglyceride, sucrose fatty acid, soybean lecithin, Tween or Span.

[0026] More preferably, the emulsifier is a monoglyceride.

[0027] In step (3), the calcium salt is dissolved in water to prepare a calcium salt solution. Preferably, the calcium salt is calcium lactate, calcium chloride, or calcium gluconate. More preferably, the calcium salt is calcium lactate.

[0028] In step (4), the emulsion coating liquid is first evenly sprayed onto the surface of the rice grain substrate, and then the calcium salt solution is evenly sprayed. The sodium alginate in the emulsion coating liquid combines with the calcium salt and can form a strong "egg box" structure gel through ionic cross-linking reaction. This thermally irreversible gel can effectively reduce the penetration of water into the rice grain at room temperature and maintain its structural integrity during the high-temperature cooking process at 95℃, thereby significantly inhibiting the excessive swelling and dissolution of starch in the rice grain, fundamentally reducing the viscosity of the product and improving its edible quality.

[0029] Preferably, the rice grain matrix is ​​spread flat on a fluidized bed, and after the first spraying with an emulsion coating liquid, it is cross-linked and cured by a second spraying with a calcium salt solution. Then, it is air-dried in a fluidized bed to obtain the finished product. The amount of emulsion coating liquid and calcium salt solution used per 100g of rice grain matrix is ​​2-3mL. The air-drying conditions are: temperature: 30-70°C, wind speed: 1.5-3.0m / s, and air-drying and cooling to a moisture content of 10-15%.

[0030] More preferably, the air-drying conditions are: temperature: 50°C, wind speed: 2.5m / s, and after air-drying and cooling to a moisture content of 12%, low-viscosity cassava reconstituted rice is obtained.

[0031] All raw materials involved in this invention (cassava, sodium alginate, calcium salt, edible oil, etc.) are common, safe, and readily available food-grade materials; the equipment involved (twin-screw extruder, fluidized bed, spray system, etc.) are all general equipment in the food industry, with clear process flow, well-defined parameters, and easy to implement and promote in this field.

[0032] This invention also provides low-viscosity cassava recombinant rice prepared by the above-described method. The low-viscosity cassava recombinant rice provided by this invention solves the high viscosity problem caused by high cassava content. After steaming or cooking, it has a good texture and distinct grains, opening up a new path for the high-value utilization of cassava as a staple food, resulting in significant economic benefits. The product is gluten-free, high in dietary fiber, and aligns with current health food consumption trends, demonstrating outstanding social benefits.

[0033] The beneficial effects of this invention are as follows: (1) To address the problem of high viscosity and easy adhesion of cassava flour, this invention proposes a novel physical coating modification approach. By using sodium alginate-calcium ion crosslinking technology to encapsulate edible oil droplets, a dense hydrophobic gel film is constructed on the surface of the rice grain matrix. This film can effectively block water penetration during steaming and cooking, reducing the adhesion of the coated cassava reconstituted rice by 95.7%. This method solves the technical problem of extremely high viscosity and easy adhesion of cassava reconstituted rice, transforming it from a state of "unable to be directly steamed and cooked" into a new type of staple food product that can be steamed, has distinct grains after steaming, a suitable taste, and low viscosity. This provides a new way for the efficient utilization of cassava as a staple food.

[0034] (2) This invention uses sodium alginate as a coating material for reconstituted cassava rice. Its safety has been fully recognized by the Chinese National Food Safety Standard for the Use of Food Additives (GB 2760-2024), allowing its appropriate use in various foods as needed for production. When combined with equally safe calcium salt food additives, it forms a thermally irreversible gel film on the surface of the rice grains. This system not only has significant technical effects and excellent stability, but its safety as a food additive has also been proven over time, fully complying with Chinese and international regulations and standards. It is an ideal solution to the problem of high viscosity when cooking reconstituted rice.

[0035] (3) The method and process provided by the present invention are consistent and easy to integrate into existing reconstituted rice production lines, and have the potential for large-scale industrial production. Attached Figure Description

[0036] Fig. 1 The images shown are of the finished rice products prepared in Examples 5-9 of this invention before cooking, where A, E, and E correspond to the finished products prepared in Examples 5-9, respectively.

[0037] Fig. 2 The images show the appearance of the finished rice prepared in Examples 5-9 of this invention after steaming, where A, E, and E correspond to the finished products prepared in Examples 5-9, respectively. Detailed Implementation

[0038] The present invention will be further described below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Any modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and essence of the invention are within the scope of the invention.

[0039] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0040] Cassava flour (the factory uses mechanical crushing, pressure filtration, dehydration, and drying processes to achieve rapid detoxification; the product is cassava flour) was purchased from Danzhou Dacheng Cassava Agricultural and Sideline Food Processing Factory. Monoglycerides (CAS No.: 123-94-4) and sodium alginate were purchased from Henan Anrui Biotechnology Co., Ltd.

[0041] Twin-screw extruder, model: FMHE22-32 (Hunan Fumac Food Engineering Technology Co., Ltd.).

[0042] Example 1 This embodiment provides a method for preparing low-viscosity cassava recombinant rice, the specific steps of which are as follows: S1. Cassava flour and monoglycerides are mixed in a mass ratio of 98:2 and fed into the feed trough of a twin-screw extruder. The moisture content is adjusted to 35% (by calculation and adjustment based on the feeding speed and water inlet speed). The material passes through the mixing and preheating zone 1, the extrusion and conveying zone 2, the pregelatinization zone 3, the gelatinization and shearing zone 4, and the high-pressure melting zone 5 before being extruded into the furnace. It is then cut into shape by a die and a cutting machine to obtain rice grain matrix.

[0043] The process employs twin-screw extrusion and granulation under the following conditions: feeding speed 30 kg / h, zone 1 temperature 50°C, zone 2 temperature 60°C, zone 3 temperature 80°C, zone 4 temperature 90°C, zone 5 temperature 65°C, and pressure 5.6 MPa. The material passes through an extrusion die, and the cutting speed is maintained at 1000 rpm to ensure consistent cutting and forming.

[0044] S2. Slowly add sodium alginate to distilled water at 50-60°C with high-speed stirring (approximately 300 rpm) until completely dissolved to obtain a sodium alginate solution. Then add glycerol to the sodium alginate solution and stir until homogeneous to obtain the aqueous phase. Mix coconut oil and monoglycerides, gently heat (50-60°C) and stir to completely dissolve the monoglycerides in the coconut oil to obtain the oil phase. Place the aqueous phase in a beaker, turn on the homogenizer, and slowly add the oil phase to the aqueous phase for 3-5 minutes until a uniform, stable, milky white oil-in-water (O / W) emulsion is formed to obtain the emulsion coating liquid.

[0045] The mass ratio of sodium alginate, glycerin, coconut oil, monoglyceride, and distilled water is 1.0:0.5:20.0:1.0:77.5. Pour into a spray bottle and set aside.

[0046] S3. Add calcium lactate to distilled water and stir until completely dissolved to obtain a calcium lactate solution with a concentration of 20 g / L. Pour the solution into a spray bottle for later use.

[0047] S4. Spread the rice grain matrix evenly on a fluidized bed, spray the emulsion coating liquid evenly on the rice grain matrix, and then immediately spray the calcium salt solution evenly (about 2 mL for every 100g of rice grain matrix). After passing through the fluidized bed, the temperature is 50°C and the air speed is 2.5m / s. After air drying and cooling to a moisture content of 15%, low-viscosity cassava reconstituted rice is obtained.

[0048] Example 2 This embodiment provides a method for preparing low-viscosity cassava recombinant rice, the specific steps of which are as follows: S1. Cassava flour and monoglycerides are mixed in a ratio of 98:2 and fed into the feed trough of a twin-screw extruder. The moisture content is adjusted to 40% (by calculating and adjusting the feeding speed and water inlet speed). The material passes through the mixing and preheating zone 1, the extrusion and conveying zone 2, the pregelatinization zone 3, the gelatinization and shearing zone 4, and the high-pressure melting zone 5 before being extruded into the furnace. It is then cut into shape by a die and a cutting machine to obtain rice grain matrix.

[0049] The process employs twin-screw extrusion and granulation under the following conditions: feeding speed 30 kg / h, zone 1 temperature 50°C, zone 2 temperature 60°C, zone 3 temperature 80°C, zone 4 temperature 90°C, zone 5 temperature 65°C, and pressure 5.6 MPa. The material passes through an extrusion die, and the cutting speed is maintained at 1000 rpm to ensure consistent cutting and forming.

[0050] S2. Slowly add sodium alginate to distilled water at 50-60°C under high-speed stirring (about 300 rpm) until completely dissolved to obtain a sodium alginate solution. Then add glycerol to the sodium alginate solution and stir evenly to obtain an aqueous phase. Mix coconut oil and monoglyceride, gently heat (50-60°C) and stir to completely dissolve the monoglyceride in the coconut oil to obtain an oil phase. Place the aqueous phase in a beaker, turn on the homogenizer, and slowly add the oil phase to the aqueous phase for 3-5 minutes until a uniform, stable, milky white oil-in-water (O / W) emulsion is formed to obtain an emulsion coating liquid.

[0051] The mass ratio of sodium alginate, glycerin, coconut oil, monoglyceride, and distilled water is 0.25:0.25:20.0:0.5:79.0. Pour into a spray bottle and set aside.

[0052] S3. Add calcium lactate to distilled water and stir until completely dissolved to obtain a calcium lactate solution with a concentration of 20 g / L. Pour the solution into a spray bottle for later use.

[0053] S4. Spread the rice grain matrix evenly on a fluidized bed, spray the emulsion coating liquid evenly on the rice grain matrix (about 2 mL per 100g of rice grain matrix), and then spray the calcium salt solution evenly (about 2 mL per 100g of rice grain matrix). Pass it through the fluidized bed at a temperature of 50°C and an air velocity of 2.5m / s. After air drying and cooling to a moisture content of 12%, low-viscosity cassava reconstituted rice is obtained.

[0054] Example 3 This embodiment provides a method for preparing low-viscosity cassava recombinant rice, the specific steps of which are as follows: S1. Cassava flour and monoglycerides are mixed in a ratio of 97:3 and fed into the feed trough of a twin-screw extruder. The moisture content is adjusted to 30% (by calculating and adjusting the feeding speed and water inlet speed). The material passes through the mixing and preheating zone 1, the extrusion and conveying zone 2, the pregelatinization zone 3, the gelatinization and shearing zone 4, and the high-pressure melting zone 5 before being extruded into the furnace. It is then cut into shape by a die and a cutting machine to obtain rice grain matrix.

[0055] The process employs twin-screw extrusion and granulation under the following conditions: feeding speed 30 kg / h, zone 1 temperature 50°C, zone 2 temperature 60°C, zone 3 temperature 80°C, zone 4 temperature 90°C, zone 5 temperature 65°C, and pressure 5.6 MPa. The material passes through an extrusion die, and the cutting speed is maintained at 1000 rpm to ensure consistent cutting and forming.

[0056] S2. Slowly add sodium alginate to distilled water at 50-60°C under high-speed stirring (about 300 rpm) until completely dissolved to obtain a sodium alginate solution. Then add glycerol to the sodium alginate solution and stir evenly to obtain an aqueous phase. Mix coconut oil and monoglyceride, gently heat (50-60°C) and stir to completely dissolve the monoglyceride in the coconut oil to obtain an oil phase. Place the aqueous phase in a beaker, turn on the homogenizer, and slowly add the oil phase to the aqueous phase for 3-5 minutes until a uniform, stable, milky white oil-in-water (O / W) emulsion is formed to obtain an emulsion coating liquid.

[0057] The mass ratio of sodium alginate, glycerin, coconut oil, monoglyceride, and distilled water is 0.75:0.75:30.0:1.5:67.0. Pour into a spray bottle and set aside.

[0058] S3. Add calcium lactate to distilled water and stir until completely dissolved to obtain a calcium lactate solution with a concentration of 20 g / L. Pour the solution into a spray bottle for later use.

[0059] S4. Spread the rice grain matrix evenly on a fluidized bed, spray the emulsion coating liquid evenly on the rice grain matrix (about 2 mL per 100g of rice grain matrix), and then spray the calcium salt solution evenly (about 2 mL per 100g of rice grain matrix). Pass it through the fluidized bed at a temperature of 50°C and an air velocity of 2.5m / s. After air drying and cooling to a moisture content of 12%, low-viscosity cassava reconstituted rice is obtained.

[0060] Example 4 This embodiment provides a method for preparing low-viscosity cassava recombinant rice, the specific steps of which are as follows: S1. Cassava flour and monoglycerides are mixed in a ratio of 99:1 and fed into the feed trough of a twin-screw extruder. The moisture content is adjusted to 36% (by calculation and adjustment based on the feeding speed and water inlet speed). The material passes through the mixing and preheating zone 1, the extrusion and conveying zone 2, the pregelatinization zone 3, the gelatinization and shearing zone 4, and the high-pressure melting zone 5 before being extruded into the furnace. It is then cut into shape by a die and a cutting machine to obtain rice grain matrix.

[0061] The process employs twin-screw extrusion and granulation under the following conditions: feeding speed 30 kg / h, zone 1 temperature 50°C, zone 2 temperature 60°C, zone 3 temperature 80°C, zone 4 temperature 90°C, zone 5 temperature 65°C, and pressure 5.6 MPa. The material passes through an extrusion die, and the cutting speed is maintained at 1000 rpm to ensure consistent cutting and forming.

[0062] S2. Slowly add sodium alginate to distilled water at 50-60°C with high-speed stirring (about 300 rpm) until completely dissolved to obtain a sodium alginate solution. Then add glycerol to the sodium alginate solution and stir evenly to obtain an aqueous phase. Mix coconut oil and monoglyceride, gently heat (50-60°C) and stir to completely dissolve the monoglyceride in the coconut oil to obtain an oil phase. Place distilled water in a beaker, turn on the homogenizer, and slowly add the oil phase to the aqueous phase for 3-5 minutes until an oil-in-water (O / W) emulsion is formed to obtain an emulsion coating liquid.

[0063] The mass ratio of sodium alginate, glycerin, coconut oil, monoglyceride, and distilled water is 1.0:0.5:30.0:1.0:67.5. Pour into a spray bottle and set aside.

[0064] S3. Add calcium lactate to distilled water and stir until completely dissolved to obtain a calcium lactate solution with a concentration of 20 g / L. Pour the solution into a spray bottle for later use.

[0065] S4. Spread the rice grain matrix evenly on a fluidized bed, spray the emulsion coating liquid evenly on the rice grain matrix (about 2 mL per 100g of rice grain matrix), and then spray the calcium salt solution evenly (about 2 mL per 100g of rice grain matrix). Pass it through the fluidized bed at a temperature of 50°C and an air velocity of 2.5m / s. After air drying and cooling to a moisture content of 12%, low-viscosity cassava reconstituted rice is obtained.

[0066] Example 5 This embodiment provides a method for preparing low-viscosity cassava recombinant rice, the specific steps of which are as follows: S1. Cassava flour and monoglycerides are mixed in a ratio of 99:1 and fed into the feed trough of a twin-screw extruder. The moisture content is adjusted to 38% (by calculation and adjustment based on the feeding speed and water inlet speed). The material passes through the mixing and preheating zone 1, the extrusion and conveying zone 2, the pregelatinization zone 3, the gelatinization and shearing zone 4, and the high-pressure melting zone 5 before being extruded into the furnace. It is then cut into shape by a die and a cutting machine to obtain rice grain matrix.

[0067] The process employs twin-screw extrusion and granulation under the following conditions: feeding speed 30 kg / h, zone 1 temperature 50°C, zone 2 temperature 60°C, zone 3 temperature 80°C, zone 4 temperature 90°C, zone 5 temperature 65°C, and pressure 5.6 MPa. The material passes through an extrusion die, and the cutting speed is maintained at 1000 rpm to ensure consistent cutting and forming.

[0068] S2. Slowly add sodium alginate to distilled water at 50-60°C under high-speed stirring (about 300 rpm) until completely dissolved to obtain a sodium alginate solution. Then add glycerol to the sodium alginate solution and stir evenly to obtain an aqueous phase. Mix coconut oil and monoglyceride, gently heat (50-60°C) and stir to completely dissolve the monoglyceride in the coconut oil to obtain an oil phase. Place the aqueous phase in a beaker, turn on the homogenizer, and slowly add the oil phase to the aqueous phase for 3-5 minutes until a uniform, stable, milky white oil-in-water (O / W) emulsion is formed to obtain an emulsion coating liquid.

[0069] The mass ratio of sodium alginate, glycerin, coconut oil, monoglyceride, and distilled water is 1.0:0.5:20.0:1.0:77.5. Pour into a spray bottle and set aside.

[0070] S3. Add calcium lactate to distilled water and stir until completely dissolved to obtain a calcium lactate solution with a concentration of 20 g / L. Pour the solution into a spray bottle for later use.

[0071] S4. Spread the rice grain matrix evenly on a fluidized bed, spray the emulsion coating liquid evenly on the rice grain matrix (about 2 mL per 100g of rice grain matrix), and then spray the calcium salt solution evenly (about 2 mL per 100g of rice grain matrix). Pass it through the fluidized bed at a temperature of 50°C and an air velocity of 2.5m / s. After air drying and cooling to a moisture content of 12%, low-viscosity cassava reconstituted rice is obtained.

[0072] Example 6 The other operating steps are the same as in Example 5, except that the concentration of the calcium lactate solution is changed to 10 g / L.

[0073] Example 7 The other operating steps are the same as in Example 5, except that the cooking oil is changed to peanut oil.

[0074] Example 8 The other operating steps are the same as in Example 5, except that sodium alginate and glycerin are not added, and the mass ratio of coconut oil, monoglyceride and distilled water is 20.0:1.0:79.0.

[0075] Example 9 The other operating steps are the same as in Example 5, except that no edible oil and emulsifier are added, and the mass ratio of sodium alginate, glycerin and distilled water is 1.0:0.5:98.5.

[0076] Test Example 1 This test example compares the finished rice produced in Examples 5-9 of the present invention in terms of appearance and structure before and after cooking.

[0077] Steaming method: Place cassava-reconstituted rice and water in a steamer in a 1:1 ratio and steam for 8 minutes.

[0078] See attached document for detailed results. Figs. 1-2 As shown, Group A is the finished rice of Example 5, Group B is the finished rice of Example 6, Group C is the finished rice of Example 7, Group D is the finished rice of Example 8, and Group E is the finished rice of Example 9.

[0079] from Figs. 1-2 As can be seen, Group A's finished rice is the best in terms of both appearance (fullness) and grain edge distinctness, with larger and more uniform grains. Groups B through E have more blurred edges compared to Group A. Group D's finished rice contains white substances (presumably coconut oil that floated to the surface during cooking), while Group E exhibits a flat, sheet-like surface with significant adhesion. Therefore, the selection of edible oil and the proper proportions of each component are crucial.

[0080] Test Example 2 The cassava recombinant rice prepared in Examples 1-9 of this invention was cooked using the cooking method of Test Example 1, cooled to room temperature, and compared using a texture analyzer.

[0081] Detection method: To simulate the human chewing process, the compression count was set to 2 times. The probe was P / 36, the pre-test velocity was 1 mm / s, the test velocity was 2 mm / s, the post-test velocity was 1 mm / s, the compression force was 50%, the trigger force was 5g, and the time interval was 5s.

[0082] The specific results are shown in the table below: Table 1. Texture characteristics of cassava-reconstituted rice

[0083] As shown in Table 1 above, the adhesion of the coated cassava reconstituted rice during cooking decreased by 95.7%. To reduce the viscosity of the cassava reconstituted rice, the distribution of each component needs to be controlled within a suitable range. Compared with Examples 1-5, Examples 6-9 showed a significant decrease in hardness and a significant increase in viscosity, especially Examples 8 and 9. This indicates that sodium alginate and edible oil in the emulsion coating are both indispensable, and the concentration of calcium lactate solution and the choice of edible oil have a significant impact on the performance of the cassava reconstituted rice.

[0084] Test Example 3 Sensory evaluation was conducted on the cooked cassava-reconstituted rice from the above embodiments. The sensory evaluation criteria in Table 2 were revised based on the national standard GB / T 15682-2008 "Grain and Oil Inspection: Cooking and Eating Quality of Paddy Rice". Following GB / T10220, ten evaluators of different genders and ages, with sensitive senses, were selected to conduct a double-blind sensory evaluation. Table 3 shows the average evaluation scores.

[0085] Table 2. Sensory rating criteria

[0086] Table 3. Sensory evaluation scores

[0087] As can be seen from Table 3 above, the total scores of Examples 6-9 are all lower than those of Examples 1-5. Example 9 has the lowest score of 55, indicating that edible oil plays the most crucial role in reducing the weight of the reconstituted cassava rice. Examples 7 and 8 scored only 67 and 65 points respectively, suggesting that the choice of edible oil and the presence of sodium alginate are very important. Example 6 scored 78 points, which, although relatively close to the scores of Examples 1-5, still demonstrates the importance of the calcium lactate solution concentration. The reconstituted cassava rice prepared by this invention exhibits excellent quality in all aspects, receives high praise, and is suitable for widespread promotion and market expansion.

[0088] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing low-viscosity cassava reconstituted rice, characterized in that, Includes the following steps: (1) Cassava flour and monoglycerides are mixed at a mass ratio of 95-99:1-5, and water is added and stirred to obtain a mixture with a moisture content of 28-40%. After the mixture is gelatinized, it is cut and granulated to obtain a rice grain matrix. (2) Sodium alginate, glycerol, and water are heated and mixed to obtain an aqueous phase, and edible oil and emulsifier are heated and mixed to obtain an oil phase. The oil phase is added to the aqueous phase and emulsified to obtain an emulsion coating liquid; the mass ratio of sodium alginate, glycerol, edible oil, emulsifier, and water is 0.25-1.5:0.25-1.0:10-30:0.5-1.5:60-89; (3) Dissolve the calcium salt in water to prepare a calcium salt solution with a concentration of 10-20 g / L; (4) After the emulsion coating liquid is evenly sprayed onto the surface of the rice grain matrix, the calcium salt solution is then evenly sprayed, and then air-dried at a temperature of 30-70°C to obtain the low viscosity cassava recombinant rice.

2. The preparation method according to claim 1, characterized in that, In step (1), cassava flour and monoglycerides are mixed at a mass ratio of 97-99:1-3; the moisture content of the mixture is controlled at 30-40%.

3. The preparation method according to claim 1 or 2, characterized in that, In step (1), the mixed materials are fed into the feed trough of the extruder. The materials pass through the mixing and preheating zone 1, the extrusion and conveying zone 2, the pregelatinization zone 3, the gelatinization and shearing zone 4, and the high-pressure melting zone 5, and are then cut into shape. The feeding speed is 30-40 kg / h, the temperature of zone 1 is 40-60°C, the temperature of zone 2 is 50-70°C, the temperature of zone 3 is 70-90°C, the temperature of zone 4 is 75-90°C, the temperature of zone 5 is 60-80°C, and the pressure is 4-7 MPa.

4. The preparation method according to claim 1, characterized in that, In step (2), the preparation method of the emulsion coating liquid includes: adding sodium alginate to water at 50-60°C, stirring continuously until completely dissolved, then adding glycerol and stirring evenly to obtain an aqueous phase; mixing edible oil and emulsifier, stirring at 50-60°C to dissolve the emulsifier in the edible oil to obtain an oil phase; and adding the oil phase to the aqueous phase to emulsify and obtain the emulsion coating liquid.

5. The preparation method according to claim 1 or 4, characterized in that, The mass ratio of sodium alginate, glycerin, edible oil, emulsifier, and water is 1.0:0.5:20:1.0:77.

5.

6. The preparation method according to claim 1, characterized in that, The edible oil is coconut oil, palm oil, butter, olive oil, rapeseed oil, peanut oil, soybean oil, corn oil, or sunflower seed oil; the emulsifier is monoglyceride, sucrose fatty acid, soybean lecithin, Tween, or Span.

7. The preparation method according to claim 1, characterized in that, In step (3), the calcium salt is calcium lactate, calcium chloride, or calcium gluconate.

8. The preparation method according to claim 1, characterized in that, In step (4), the rice grain matrix is ​​spread flat on a fluidized bed, and after the first spraying with emulsion coating liquid, it is cross-linked and cured by a second spraying with calcium salt solution. Then, it is air-dried in a fluidized bed to obtain the finished product. The amount of emulsion coating liquid and calcium salt solution used for each 100g of rice grain matrix is ​​2-3mL. The air-drying conditions are: temperature: 30-70°C, wind speed: 1.5-3.0m / s, and air-drying and cooling to a moisture content of 10-15%.

9. The preparation method according to claim 8, characterized in that, The air-drying conditions are: temperature: 50°C, wind speed: 2.5m / s, and air-drying and cooling to a moisture content of 12% to obtain low-viscosity cassava reconstituted rice.

10. Low-viscosity cassava recombinant rice prepared by the preparation method according to any one of claims 1-9.

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