Preparation method of extruded instant rice

Abstract

The application discloses a preparation method of extruded instant rice, and belongs to the technical field of instant food processing. The method comprises the following steps: 1) selecting raw material rice, 2) crushing and sieving, 3) mixing materials, 4) extruding, aging, cutting and granulating, 5) fluidized bed drying, 6) high-speed circulating hot air puffing, and 7) cooling and packaging. The product produced according to the application is white, has no any spot and impurity adhesion, has no any peculiar smell, the rice grains are complete, the internal part has no spot, the finished product can be eaten after being soaked in water with a temperature higher than 90 DEG C for 5 minutes, the rice grains have a certain chewiness (moderate hardness, viscosity and elasticity) after being rehydrated, and have the aroma of rice.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of instant food processing, in particular to a preparation method of extruded instant rice porridge. BACKGROUND

[0002] Rice porridge is usually made by directly brewing or slightly cooking rice with water or soup, and has a taste between rice and porridge, with a certain chewiness, smoothness and not soft. Making rice porridge requires cooking rice in advance, and rice is not convenient to store and is prone to mold. It is not convenient to eat rice porridge.

[0003] Currently, commercially available instant rice porridge cannot meet the needs of instant rice porridge. For example, self-heating instant rice takes too long to brew, and needs to be heated by a self-heating bag for about 15 minutes before use. CN109907234A discloses a preparation method of nutritional self-heating rice, which is made of rice, dispersing agent and natural color auxiliary material, through the steps of material mixing, extrusion curing, microwave drying, fluidized bed air cooling and packaging. It takes 10-20 minutes to brew when eating. After rehydration, the fast-brewing instant rice is soft and not rice but porridge. Therefore, there is a need for a fast-brewing instant rice porridge product similar to instant noodles, which can be quickly brewed and eaten (3-5 minutes) and has good taste. SUMMARY

[0004] In view of the problems existing in the prior art, the present application provides a preparation method of extruded instant rice porridge, which uses rice powder as the main raw material and adds a small amount of wheat flour. By controlling the double screw extrusion process parameters and combining fluidized bed drying and high-speed circulating hot air puffing, instant rice porridge with certain chewiness (moderate hardness, viscosity and elasticity) can be obtained. The product can meet the dual requirements of convenience and taste of rice porridge, and the preparation process is simple, efficient and waste-free.

[0005] The preparation method of the extruded instant rice porridge of the present application comprises the following steps:

[0006] (1) Selecting raw materials: selecting one or more than two of japonica rice, indica rice and glutinous rice;

[0007] (2) Crushing and sieving: crushing the raw material rice in step (1) in a crusher and sieving through an 80-mesh sieve to obtain rice powder;

[0008] (3) Mixing materials: adding emulsifier and wheat flour to the rice powder obtained in step (2) and mixing uniformly with a stirrer to form a mixture;

[0009] (4) extrusion ripening, cutting and granulating: the mixture prepared in step (3) is fed into a double screw extruder, in which the mixture is conveyed to an extrusion die by an extrusion screw, and is formed by the extrusion screw and the extrusion die, and is cut into rice grains by a cutting knife at the end of the extrusion die of the double screw extruder;

[0010] (5) drying: the extruded rice grains in step (4) are dried in a fluidized bed;

[0011] (6) puffing: the dried rice grains in step (5) are puffed in a hot air circulating oven;

[0012] (7) cooling and packaging: the puffed rice grains in step (6) are fully cooled and then packaged.

[0013] The emulsifier in step (3) can be one or more of monoglyceride, lecithin and sucrose ester, and the amount is 0.3-0.5% of the mass of the rice powder.

[0014] The amount of the wheat powder in step (3) is 5-10% of the total mass of the rice powder.

[0015] The conditions of the extrusion ripening, cutting and granulating in step (4) are as follows: the liquid feeding speed of the feeding end of the double screw extruder is 2.5-4.9 kg / h, the screw rotation speed is 170-190 r / min, and the feeding speed is 10-14 kg / h; the temperatures of the five zones of the sleeve of the double screw extruder are set to be 50-70℃, 115-135℃, 120-140℃, 50-70℃ and 40-60℃, respectively, and the rotation speed of the cutting knife is 1800-2200 r / min.

[0016] The drying conditions in step (5) are as follows: the drying is carried out in a fluidized bed at 40-60℃, and the water content of the rice grains is reduced to 20-25% after drying.

[0017] The puffing conditions in step (6) are as follows: the puffing temperature is 130-160℃, the puffing time is 30-60 s, the air speed is 1100-2100 r / min, and the water content of the rice grains is less than 10% after puffing.

[0018] Compared with the existing preparation process of instant rice, the present application has the following obvious advantages:

[0019] ① A small amount of wheat powder is added, which can prevent the rice grains from being mushy during rehydration, improve the elasticity and chewiness of the rice grains, and will not affect the flavor of rice;

[0020] ② The extruded rice grains are dried to a certain water content in a fluidized bed, and then are puffed in a hot air circulating oven, and the puffing degree of the rice grains can be controlled by precisely controlling the puffing temperature and the air speed, so that the brewing time is shortened while the chewiness of the rice grains is maintained;

[0021] ③The whole process can realize continuous production;

[0022] ④The product does not need to use a self-heating bag to heat, and only needs to be brewed with hot water for a few minutes to be edible, has small volume and is convenient to carry.

[0023] ⑤The application solves the problems of long rehydration time of the current self-heating instant rice, inconvenient carrying of the self-heating bag and no chewiness after rehydration of the fast-brewing instant rice. The instant rice is brewed with boiling water for only 5 min, the rice grains have chewiness (moderate hardness, viscosity and elasticity) after rehydration, and have rice aroma. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a flow chart of the method of the application.

[0025] Figure 2 It is a photo of extruded rice. DETAILED DESCRIPTION

[0026] The application will be specifically described below in combination with the drawings and examples.

[0027] Test method of bulk density:

[0028] A measuring cylinder with a range of 100 mL is filled with a certain amount of water (the volume of water filled should be such that the total volume after adding the sample does not exceed the maximum scale of the measuring cylinder), and the volume V1 is read. A certain mass of sample is taken at random, and the mass m is weighed, and it is put into the measuring cylinder to immerse, and the total volume V2 at this time is immediately read (to prevent the sample from absorbing water, resulting in too large error). Therefore, the volume of the sample is V3 = V2-V1. Each sample is measured for 3 times, and the average value is taken as the volume of the sample. The bulk density of the sample is calculated by the following formula (I):

[0029]

[0030] Test method of texture properties:

[0031] After the prepared sample is rehydrated and drained, it is cooled by forced ventilation for 20 min, and then naturally cooled at room temperature for 100 min. 8.0 g of the sample is weighed, put into the metal ring provided with the instrument, and then the sample-loaded ring is placed under the compression platen to compress the sample to be tested, attention should be paid to avoid sample overflow, and then the sample is put into the matching stainless steel pad, and then put into the fixed position of the instrument to be clamped. The instrument measures the change of force in the process of sample compression and rebound by a sensor, and the hardness, viscosity and elasticity of the sample are represented by numerical values. Each sample is measured for 3 times, and the average value is taken.

[0032] Example 1

[0033] Take 5 kg of japonica rice, put into the crusher, crush, pass through 80 mesh sieve, add 15 g of monoglyceride and 250 g of wheat flour, mix evenly, the mixture is sent to the solid feeder at a speed of 10 kg / h, then sent to the twin-screw extruder, the temperature of each temperature zone is adjusted to 50, 115, 120, 50, 40℃ respectively, the screw speed is 170 r / min, the liquid feeding speed is 2.5 kg / h. The cooked material is cut under the condition that the shear cutter speed is 1800 r / min, transported to the fluidized bed at 40℃ for drying, after drying, the moisture content of the rice is 20%, then placed in a hot air circulating oven, set the temperature to 130℃, the air speed to 2100 r / min, puffing for 50 s, after cooling, the instant rice product is obtained. According to the above method, the product bulk density is 421 g / L, the hardness after rehydration is 1.43 kgf, the viscosity is 0.10 kgf, and the elasticity is 0.68 kgf.

[0034] Example 2

[0035] Take 5 kg of indica rice, put into the crusher, crush, pass through 80 mesh sieve, add 20 g of lecithin and 400 g of wheat flour, mix evenly, the mixture is sent to the solid feeder at a speed of 12 kg / h, then sent to the twin-screw extruder, the temperature of each temperature zone is adjusted to 60, 125, 130, 60, 50℃ respectively, the screw speed is 180 r / min, the liquid feeding speed is 3.6 kg / h. The cooked material is cut under the condition that the shear cutter speed is 2000 r / min, transported to the fluidized bed at 50℃ for drying, after drying, the moisture content of the rice is 22%, then placed in a hot air circulating oven, set the temperature to 140℃, the air speed to 1800 r / min, puffing for 40 s, after cooling, the instant rice product is obtained. According to the above method, the product bulk density is 390 g / L, the hardness after rehydration is 1.22 kgf, the viscosity is 0.06 kgf, and the elasticity is 0.65 kgf.

[0036] Example 3

[0037] Take 5 kg of japonica rice, put into the crusher, crush, pass through 80 mesh sieve, add 25 g of monoglyceride and 500 g of wheat flour, mix evenly, the mixture is sent to the solid feeder at a speed of 14 kg / h, then sent to the double screw extruder, the temperature of each temperature zone is adjusted to 70, 135, 140, 70, 60℃ respectively, the screw speed is 190 r / min, the liquid feeding speed is 4.9 kg / h. The cooked material is cut under the condition that the shear cutter speed is 2200 r / min, and then transported to the 60℃ fluidized bed for drying. After drying, the moisture content of the rice is 25%, then placed in a hot air circulating oven with a temperature of 160℃ and a wind speed of 1100 r / min, and expanded for 30 s. After cooling, the instant rice product is obtained. The product bulk density is 448 g / L, the hardness after rehydration is 1.62 kgf, the viscosity is 0.13 kgf, and the elasticity is 0.73 kgf.

[0038] Example 4

[0039] Take 5 kg of japonica rice, put into the crusher, crush, pass through 80 mesh sieve, add 20 g of monoglyceride and 400 g of wheat flour, mix evenly, the mixture is sent to the solid feeder at a speed of 12 kg / h, then sent to the double screw extruder, the temperature of each temperature zone is adjusted to 60, 125, 130, 60, 50℃ respectively, the screw speed is 180 r / min, the liquid feeding speed is 4.2 kg / h. The cooked material is cut under the condition that the shear cutter speed is 2000 r / min, and then transported to the 50℃ fluidized bed for drying. After drying, the moisture content of the rice is 24%, then placed in a hot air circulating oven with a temperature of 130℃ and a wind speed of 1500 r / min, and expanded for 60 s. After cooling, the instant rice product is obtained. The product bulk density is 463 g / L, the hardness after rehydration is 1.79 kgf, the viscosity is 0.15 kgf, and the elasticity is 0.70 kgf.

[0040] Comparative Example 1 without emulsifier

[0041] 5 kg of japonica rice was weighed and ground in a grinder, then passed through an 80-mesh sieve. 400 g of wheat flour was added and mixed thoroughly. The mixture was fed into a solid feeder at a rate of 12 kg / h, and then into a twin-screw extruder. The temperatures of each zone were adjusted to 60, 125, 130, 60, and 50°C, respectively, with a screw speed of 180 r / min and a liquid feed rate of 4.2 kg / h. The cooked material was cut under a shear blade speed of 2000 r / min and then conveyed to a 50°C fluidized bed for drying. After drying, the moisture content of the rice grains was 24%. The rice was then placed in a hot air circulating oven at 130°C and a wind speed of 1500 r / min for 60 seconds to puff. After cooling, the ready-to-eat rice porridge product was obtained. In the above experiment, omitting the emulsifier addition step resulted in a highly viscous extrudate after extrusion and cooking, leading to severe clumping of the rice grains cut by the shear blade and a low product yield.

[0042] Comparative Example 2 (without wheat flour)

[0043] 5 kg of japonica rice was weighed and ground in a grinder, then passed through an 80-mesh sieve. 20 g of monoglyceride was added and mixed thoroughly. The mixture was fed into a solid feeder at a rate of 12 kg / h, and then into a twin-screw extruder. The temperatures of each zone were adjusted to 60, 125, 130, 60, and 50°C, respectively, with a screw speed of 180 r / min and a liquid feed rate of 4.2 kg / h. The cooked material was cut under a shear blade speed of 2000 r / min and then conveyed to a 50°C fluidized bed for drying. After drying, the moisture content of the rice grains was 24%. The rice was then placed in a hot air circulating oven at 130°C and 1500 r / min for 60 seconds to puff. After cooling, the ready-to-eat rice porridge product was obtained. In the above experiment, omitting the step of adding wheat flour, the resulting product, after rehydration, had a porridge-like consistency and a soft, tender texture.

[0044] Comparative Example 3

[0045] 5 kg of japonica rice was weighed and ground in a grinder, then passed through an 80-mesh sieve. 20 g of monoglyceride and 400 g of wheat flour were added and mixed thoroughly. The mixture was fed into a solid feeder at a rate of 12 kg / h, and then into a twin-screw extruder. The temperatures of each zone were adjusted to 60, 125, 130, 60, and 50°C, respectively, with a screw speed of 180 r / min and a liquid feed rate of 4.2 kg / h. The cooked material was cut under a shear blade speed of 2000 r / min and then conveyed to a 50°C fluidized bed for drying. After drying, the moisture content of the rice grains was 24%. The rice was then placed in an electrically heated forced-air drying oven at 130°C for 60 seconds to puff. After cooling, the ready-to-eat rice porridge product was obtained. In the above experiment, replacing the hot air circulating oven puffing method with a forced-air drying oven resulted in rice grains that were easily scorched and uneven in color, indicating poor puffing effect.

[0046] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for preparing extruded instant rice porridge, characterized in that, Includes the following steps: (1) Raw material selection: Select one or more of the following: japonica rice, indica rice, and glutinous rice; (2) Crushing and sieving: The rice selected in step (1) is crushed to obtain rice flour; (3) Material mixing: Add emulsifier and wheat flour to the rice flour obtained in step (2) and stir evenly; the emulsifier is one or more of monoglycerides, lecithin, and sucrose esters; the amount of emulsifier is 0.3~0.5% of the mass of rice flour; the amount of wheat flour is 5%, 8% or 10% of the total mass of rice flour; (4) Extrusion, ripening, cutting and granulation: The mixture obtained in step (3) is fed into a twin-screw extruder. The mixture is conveyed to the extrusion die by the extrusion screw. It is extruded and shaped under the action of the extrusion screw and the extrusion die. It is then cut into rice-grain shape by the shearing blade at the end of the extrusion die of the twin-screw extruder. The conditions for extrusion, ripening and cutting granulation are: liquid feeding speed at the feed end of the twin-screw extruder is 2.5~4.9 kg / h, screw speed is 170~190 r / min, solid feeding speed is 10~14 kg / h, and shearing blade speed is 1800~2200 r / min. The temperature settings of the five zones of the twin-screw extruder sleeve are 50~70℃, 115~135℃, 120~140℃, 50~70℃, and 40~60℃, respectively. (5) Drying: The rice grains extruded in step (4) are dried in a fluidized bed; the drying conditions are 40~60℃ in the fluidized bed, and the moisture content of the rice grains is reduced to 20~25% after drying. (6) Puffing: The dried rice grains from step (5) are puffed in a hot air circulating oven; the puffing temperature is 130~160℃, the puffing time is 30~60s, the wind speed is 1100~2100r / min, and the moisture content of the puffed rice grains is less than 10%; (7) Cooling and packaging: After the rice grains puffed in step (6) are fully cooled, they are packaged.

2. The extruded instant rice porridge prepared according to claim 1.

3. The method of using the extruded instant rice porridge as described in claim 2, characterized in that, Use boiling water to brew.

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