Infant rice flour with good digestion performance and preparation method thereof

Abstract

The invention discloses infant rice flour with good digestive performance and a preparation method thereof. The invention provides a production process flow system for crushing rice starch grains into powder through a soaking and rubbing method and a method for preparing prefabricated powder by using the production process flow system. The production process flow is systematically integrated and fully combined with the quality standard and related attributes of the rice products, meets the characteristics of raw material properties, molecular structures and the like, determines the technical index requirements of the product industrial production process flow and the crushing and milling production related equipment, productivity and the like, and can solve the problem of quality stability of fine crushing and milling of the rice products. The grain size of the grains can reach 99.8% or above through a 100-mesh sieve, and meanwhile, the breakage rate of the granular starch is stabilized to be less than 5% or below. Compared with common infant rice flour, the infant rice flour further prepared from the rice flour prepared through the method is better in hydrolysis performance, easier to digest and absorb, less in amino acid loss and higher in nutritional value compared with common rice flour sold in the market.

Description

Technical Field

[0001] The invention relates to infant rice flour with good digestibility and a preparation method thereof, and belongs to the technical field of food processing. Background Art

[0002] Rice is rich in nutrients such as starch, protein, minerals, and vitamins. Rice protein is non-allergenic, and rice starch is easily digested after cooking. Therefore, rice cereal is very suitable as a baby food. As a baby's first complementary food, baby rice cereal not only provides nutrition but also helps promote the transition from liquid to solid foods. Baby rice cereal is usually dissolved in water before feeding, so it must have good solubility and digestibility.

[0003] However, existing infant rice cereals have several issues. For example, large particles lead to uneven gelatinization rates, and high rates of starch granule breakage result in high viscosity and poor palatability. These issues further contribute to infants' dislike of the cereal or poor digestion and absorption. Therefore, if process improvements could be made to produce rice cereals with a dense texture, uniform particle size, lower starch damage rate, and improved digestibility, it would be beneficial to promote the industrial development of infant rice cereals.

[0004] Furthermore, common infant rice cereal production processes currently face the following technical bottlenecks and industrial challenges: Dry milling (such as claw / hammer milling) results in densely packed starch crystallite bundles due to the raw material's lack of water absorption, leading to high starch breakage rates (typically >15%) during processing, which can easily cause material adhesion and substandard product quality. While semi-dry milling reduces breakage rates to 8-12% through moderate wetting, it is still limited by the adaptability of the molecular cluster crystallization properties, resulting in poor powder texture stability and high production costs. Wet refining (including soaking, coarse grinding, and fine grinding) uses stone or diamond grinding equipment, achieving a 100-mesh pass rate of over 92%, but carries the risk of high energy consumption, high wastewater discharge, and the risk of residual impurities from the stone mill. Extrusion and puffing, which uses high temperature and high pressure to gelatinize and degrade starch, improves solubility (by 30% in dispersion), but excessive protein degradation results in a lack of elasticity, and a gelatinization degree >90% inhibits infant chewing ability. The existing technology has not yet achieved the optimal solution for industrialization in terms of texture control, production cost and industrial continuity. It is urgent to develop a new process system that takes into account low breakage rate, zero wastewater discharge, low energy consumption and chewing-promoting function. Summary of the Invention

[0005] In order to solve the deficiencies of the prior art, the present invention provides a rice starch grain pulverizing and flour making process by a "wet rubbing method", and determines the product preparation process flow according to the properties of the raw materials and molecular structure.

[0006] The present invention is achieved through the following technical solutions:

[0007] A first object of the present invention is to provide a method for preparing infant rice cereal with good digestibility, comprising the steps of:

[0008] S1, washing the rice, adding water, inoculating Lactobacillus plantarum and Saccharomyces cerevisiae, adding calcium lactate, and draining the water after natural fermentation;

[0009] S2, performing gradient centrifugal dehydration on the fermented rice grains using a filter centrifuge;

[0010] S3, the dehydrated rice grains are squeezed and rubbed using a two-roller machine;

[0011] S4, the rice powder after squeezing and rubbing is added into the air flow superfine grinding machine for superfine grinding;

[0012] S5, the rice flour after ultrafine grinding is dried to obtain the rice flour with low grain breakage rate, and a nutrition enhancer is added, mixed and packed, and sterilized to obtain infant rice flour after the packing.

[0013] In one embodiment of the present invention, the amount of water added in step S1 is 1 to 2 times the amount of rice.

[0014] In one embodiment of the present invention, the inoculation amount of cerevisiae yeast and lactic acid bacteria in step S1 is 1% to 10%, wherein the ratio of Lactobacillus plantarum to cerevisiae yeast is 1 to 3:1.

[0015] In one embodiment of the present invention, the amount of calcium lactate added in step S1 is 0.1% to 0.5% of the total weight.

[0016] In one embodiment of the present invention, the natural fermentation conditions in step S1 are 28° C. to 32° C. and the natural fermentation is 10 h to 30 h.

[0017] In one embodiment of the present invention, in step S1, the water is drained for 5 to 25 minutes after fermentation.

[0018] In one embodiment of the present invention, the gradient centrifugation in step S2 is first centrifuged at 500 rpm to 1000 rpm for 2 min to 6 min, and then centrifuged at 1000 rpm to 1500 rpm for 2 min to 5 min.

[0019] In one embodiment of the present invention, in step S3, when the two-roller machine squeezes and rubs, the angle between the rollers is 3° to 7°, the rotation speed of the first-level roller is set to 40rpm to 700rpm, and the rotation speed of the second-level roller is set to 400rpm to 1200rpm.

[0020] In one embodiment of the present invention, in step S3, during the squeezing and kneading process of the two-roller machine, a cold air flow is provided between the primary roller and the secondary roller to reduce the temperature. Furthermore, the cold air flow is 10°C to 20°C and the wind speed is 1m / s to 3m / s.

[0021] In one embodiment of the present invention, in step S4, the parameters of ultrafine grinding are air flow pressure: 0.6MPa-1.0MPa, classifying wheel speed 2000rpm-3000rpm, and feed rate 40kg / h-60kg / h.

[0022] In one embodiment of the present invention, in step S5, the drying is performed using a hot air flow drying device, the drying temperature is 50° C. to 70° C., and the drying time is 1 hour to 5 hours.

[0023] In one embodiment of the present invention, the nutritional supplement includes vitamins and minerals.

[0024] In one embodiment of the present invention, the nutritional enhancers are added according to the following contents: ferrous sulfate 6mg / 100g~14mg / 100g, vitamin C 6mg / 100g~14mg / 100g, vitamin B1 12μg / 100g~16μg / 100g, vitamin B2 14~18μg / 100g, niacin (vitamin B3) 96μg / 100g~120μg / 100g, and calcium gluconate 300mg / 100g~500mg / 100g.

[0025] In one embodiment of the present invention, sterilization is performed by low-pressure sterilization at 121° C. for 20 to 40 minutes.

[0026] The second object of the present invention is to provide infant rice cereal prepared by the method.

[0027] Beneficial effects of the present invention:

[0028] The present invention provides a rice starch grain milling process system using a "wet rubbing method" and a method for preparing pre-made flour. This integrated production process system fully integrates the quality standards and related properties of rice products, meets the characteristics of raw materials and molecular structure, and determines the technical indicators of the product industrial production process and related equipment and production capacity for milling and milling production. It can solve the quality stability of rice products during fine milling and milling. The grain size of the rice starch grains reaches a 100-mesh screening rate of over 99.8%, and the granular starch breakage rate is stabilized at less than 5%. The rice flour prepared using the present method is further prepared into infant rice flour, which has better hydrolysis performance than ordinary infant rice flour, is easier to digest and absorb, has less amino acid loss, and has higher nutritional value than ordinary rice flour available on the market. This is mainly because the low breakage rate maintains the natural structure of the starch granules, reduces nutrient loss and protein denaturation during processing, and the finer and more uniform particle size significantly improves the dispersibility and enzyme accessibility of the rice flour, promoting the full hydrolysis of starch and protein. This improves the digestion and absorption efficiency of infant rice cereal, reduces the loss of amino acids and other nutrients, and gives the product a higher nutritional utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The digestibility of rice cereal for infants and young children;

[0030] Figure 2 is the hydrolysis rate of infant rice flour;

[0031] Figure 3 It is the emulsification index of infant rice cereal. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with specific examples. These implementation cases are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, after reading the content taught by the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims appended hereto.

[0033] Source of raw materials

[0034] The rice used in this application is Northeastern japonica rice, purchased from COFCO Group, with a moisture content of 12% to 14% and an amylose content of 18% to 25%; Lactobacillus plantarum and Saccharomyces cerevisiae were purchased from Shaanxi Baichuan Biotechnology.

[0035] Test method:

[0036] 1. Rice flour starch damage rate:

[0037] Amperemetry: Instrument: Chopin SDmatic analyzer (with 35°C constant temperature reaction system, 1200 rpm stirrer), 1 / 10,000 balance. Detailed steps are as follows: Weigh 1g sample and add 50mL buffer. Mix with 1mL of 0.01mol / L iodine solution at 35°C for 10 minutes. Add 8mL of 0.2% sulfuric acid to terminate the reaction. The instrument automatically detects the current change and calculates the damaged starch value. Key parameters: temperature 35°C ± 0.5°C, stirring speed 1200 rpm ± 5 rpm, reaction time 10min ± 0.5min.

[0038] 2. Water absorption: Accurately weigh 1 g of rice flour, add 100 g of deionized water, and mix well using a magnetic stirrer; pour 15 mL of rice paste into 50 mL centrifuge tubes, freeze them in a -180°C freezer for 24 h, take them out, thaw them to room temperature, and centrifuge them at 5000 rpm for 20 min. Filter out excess water, weigh the centrifuge tubes and the sediment, and calculate the water absorption rate (R) according to the following formula.

[0039] R=[(m1—m2) / (m1—m0)]×100%

[0040] Where m0 is the mass of the centrifuge tube / g; m1 is the total mass of the centrifuge tube and sample after thawing / g; m2 is the total mass of the centrifuge tube and sediment after centrifugation / g.

[0041] 3. The mensuration of rice flour viscosity: the rice flour sample is sieved through a 0.42 mm sieve and measured for moisture according to GB / T 5497. 3.00 g of sample is weighed subsequently and 25 mL of distilled water is added to an RVA sample cartridge for pre-dispersion. The sample is then pre-sheared at 50° C. for 10 seconds at 960 rpm and then heated to 95° C. (6° C. / min at 160 rpm) at 95° C. for 10 seconds. The viscosity is then recorded using a curve analysis tool.

[0042] 4. Rice flour whiteness test method:

[0043] Zero and calibrate the whiteness meter, assemble the whiteboard components, load the rice flour samples respectively, scrape them flat, press the cover, and place the prepared flat plate in the calibrated whiteness meter to test the whiteness of the sample.

[0044] 5. Density of rice flour:

[0045] The density of rice noodles refers to the ratio of the mass of rice noodles per unit volume to its theoretical maximum density, which reflects the packing density and internal porosity of rice noodles. It is measured using a tap density meter. 10 g of rice noodles sample is weighed and placed in a dry graduated cylinder. The parameters of the tap density meter are set to an amplitude of 3 mm and a frequency of 250 times / min. The volume (V1) is recorded after 500 consecutive taps.

[0046] Calculate volume density: ρ = 10 / V1

[0047] 6. In vitro simulated digestion experiment

[0048] The simulated gastric fluid for infants was prepared as follows: 0.25 g of pepsin, 2.0 g of sodium chloride, and 0.7 mL of hydrochloric acid solution (5 mol / L) were mixed evenly, and the volume was made up to 100 mL with distilled water. The pH of the solution was adjusted to 1.5.

[0049] The preparation of simulated intestinal fluid for infants and young children is as follows: 0.68 g of potassium dihydrogen phosphate is fully dissolved in 5 ml of distilled water, and 19 ml of sodium hydroxide solution (0.2 mol / L), 40 ml of distilled water and 0.04 g of trypsin are added in sequence. After mixing evenly, the volume is made up to 100 ml with distilled water, and the pH of the solution is adjusted to 7.51.

[0050] Add 5g of infant rice cereal to 100mL of distilled water to create an infant rice cereal solution. Add 100mL of simulated gastric fluid to the rice protein solution and oscillate in a 379°C constant temperature water bath for 120 minutes at a frequency of 50 to 200 rpm. Adjust the pH of the digestion product to 7 with 1mol / L NaOH solution, and then perform a simulated intestinal digestion test. Add an equal volume of simulated intestinal fluid to the above solution and place in a 37°C water bath for 90 minutes at the same oscillation frequency. After the reaction is complete, immediately place the beaker on a 100°C heating platform and boil for 10 minutes to inactivate the enzyme. Transfer the cooled enzymatic hydrolyzate to a centrifuge tube and centrifuge at 10,000 rpm for 10 minutes. Remove the supernatant and filter through a membrane to obtain the digestion product, which is then refrigerated and stored at 4°C.

[0051] a. Determination of digestibility

[0052] The above digestion products were rotary evaporated and vacuum freeze-dried, then weighed and the digestibility (PDT) was calculated according to formula ①.

[0053]

[0054] Where: P0 is the protein content in the sample, mg; P1 is the remaining protein content after digestion in simulated gastrointestinal fluid, mg.

[0055] b. Determination of degree of hydrolysis

[0056] Place 5 mL of infant rice cereal digestion solution in a small beaker, add 60 mL of distilled water, and mix thoroughly. Titrate to a pH of 8.2 with 0.1 mol / L standard sodium hydroxide solution. Measure the pH by adding 20 mL of neutralized formaldehyde solution (prepare just before use by adding 3 mL of 0.5% phenolphthalein indicator to 50 mL of formaldehyde solution and then adding 0.1 mol / L sodium hydroxide solution dropwise until a slight reddish color appears). Record the volume of 0.1 mol / L standard sodium hydroxide solution consumed when titrating to a pH of 9.2. Calculate the degree of hydrolysis (DH) according to equations ② and ③.

[0057]

[0058] Where: h is the number of millimoles of peptide bonds cleaved per gram of rice protein after hydrolysis, mmol / g; h tot is the number of millimoles of peptide bonds per gram of rice protein, mmol / g; rice protein h tot =8.40.

[0059]

[0060] Where: B is the volume of 0.1 mol / L standard sodium hydroxide solution, m; M is the concentration of sodium hydroxide, mol / L; 1 / α is the correction factor; M p is the protein content in the substrate, g.

[0061] c. Emulsification index (EI) determination

[0062] The digestive fluid of infant rice cereal was placed in a sealed, transparent sample bottle and stored at 4°C. The height of the emulsion layer (H) and the total height of the digestive fluid (H) were measured regularly on the 1st, 7th, and 15th day. The emulsification index was calculated according to formula (8).

[0063]

[0064] Where: H is the height of the emulsion layer, cm; H0 is the total height, cm.

[0065] 7. Determination of amino acid content:

[0066] The infant rice cereal digest was pre-frozen in a -50°C ultra-low temperature freezer for 4 hours and then dried in a freeze dryer at -20°C for 20 hours. The freeze-dried infant rice cereal digest was then hydrolyzed with 6N HCl in a hydrolysis tube, purged with nitrogen, and treated at 110°C for 24 hours before column analysis. Amino acid content was determined using an automated amino acid analyzer.

[0067] In this application, the inventors utilize the properties of rice raw materials and the microporous structure of the ridges in starch crystals. The pores and holes from the core cavity inside the starch granules to the surface of the granules provide channels for water and enzymes. By adding plant lactobacillus and brewer's yeast for mixed fermentation and adding calcium lactate, the inventors ferment the rice with microorganisms. While the grain starch granules fully absorb water and soften, the natural polysaccharide polycrystalline system composed of alternating amorphous layers and crystalline layers of the cell structure of the caryopsis starch granules is more fully untied, creating process conditions for subsequent crushing and fine grinding processes. After fermentation and dissociation, the starch granules are ultrafinely ground through optimized mechanical treatment to obtain high-purity free starch. Its solubility and processing adaptability are significantly improved, while reducing production energy consumption and meeting the quality requirements of infant food for high solubility and low allergenicity.

[0068] In the present application, the inventors use a centrifuge to remove some of the free water on the surface of the grain and between the pores of the particles, which helps to reduce the risk of adhesion or flaking on the roller surface of the "roller equipment" and reduces the water content during the drying process. In actual operation, the rice after soaking and swelling has a relatively loose structure, and centrifugation is very easy to clog the filter, resulting in inability to operate continuously and it is difficult to reduce the moisture content to about 30%. After a lot of experimental exploration, the inventors used the step-by-step centrifugation method of the present invention to achieve centrifugation of wet rice, successfully reducing the moisture content of rice to about 30%, and the equipment has low energy consumption and can be operated continuously. Compared with drying and dehydration, the operation time is greatly shortened and the energy consumption is greatly reduced.

[0069] In contrast, if drying is used for dehydration, although theoretically the moisture content can be reduced to 30%, there are the following problems: high energy consumption: hot air drying requires a long time (2-3 hours) to maintain a temperature of 60-80°C, and the energy consumption is 3-5 times that of centrifugal dehydration; risk of material denaturation: high temperature may cause gelatinization on the surface of starch granules, forming a hard shell layer, affecting the subsequent crushing effect; low efficiency: the drying process requires intermittent operation, which cannot achieve continuous production, and the moisture control accuracy is poor (±5%). Therefore, the present invention not only avoids the defects of the drying process, but also greatly improves production efficiency and product quality, providing an ideal moisture control solution for subsequent crushing and fine grinding.

[0070] In the present application, because the rice caryopsis grain aggregate has a “clustered” branching structure of ring lines, it is basically composed of linear starch chains alternating crystalline and amorphous thin layers, and there are annular fine lines unit cells with gaps and their structures. After microbial treatment and water absorption expansion, its dense structure is evacuated and disintegrated along the pore annular fine lines. Then, by adjusting the gap between the rollers, the caryopsis grains are subjected to extrusion, rubbing and tearing stress, and disintegrated and broken into grains of different sizes (30 mesh 0.60mm-60 mesh 0.25mm). This operation is very consistent with the pathway structural mechanism of caryopsis grain formation; it is beneficial to reduce breakage when separating starch granules, and it also avoids the number of collisions between the rotor and stator placed in the inner cavity of the airflow superfine grinder after the caryopsis grains are disintegrated and broken, which helps to greatly reduce the degree of starch damage during airflow superfine grinding. In addition, it is also beneficial to reduce the energy consumption of the airflow mill operating power.

[0071] The technical solutions of the present invention are described in detail below with reference to specific embodiments. In the following embodiments, unless otherwise specified, the reagents, materials and equipment used can be purchased from commercial sources, or prepared by conventional methods, or are commonly used in the industry.

[0072] Example 1:

[0073] The preparation steps of infant rice flour of the present invention are as follows:

[0074] (1) After washing the raw rice, add 1.5 times the weight of rice water, inoculate Lactobacillus plantarum: Saccharomyces cerevisiae in a ratio of 3:1 according to an inoculum amount of 5% of the total weight, and add 0.3% of the total weight of calcium lactate. Ferment at 30°C for 16 hours. At this time, the moisture content of the rice grains is measured to be about 70%;

[0075] (2) The fermented rice grains were dehydrated using a filter centrifuge, first centrifuged at 800 rpm for 3 minutes to remove surface water, and then centrifuged at 1200 rpm for 4 minutes. After centrifugation, the moisture content of the rice grains was measured to be about 30%;

[0076] (3) The rice grains after centrifugation were squeezed and rubbed using a two-roller machine, wherein the speed of the first roller was set to 400 rpm, the speed of the second roller was set to 1000 rpm, the gap between the rollers was 0.5 mm, the deflection angle of the two roller axes was 3°, the cold air speed was 2 m / s, and the temperature was 20°C;

[0077] (4) adding the rice powder after squeezing and rubbing into an air flow superfine grinder for superfine grinding, wherein the parameters of the air flow superfine grinder are set to a grinding pressure of 0.7 MPa and a classifying wheel speed of 2500 rpm;

[0078] (5) The ultrafinely ground rice flour was dried using a hot air flow drying device at a drying temperature of 65° C. for 15 min. The rice flour with a water content of about 30% was dried to below 14%. A nutritional supplement (ferrous sulfate 10 mg / 100 g, vitamin C 10 mg / 100 g, vitamin B1 14 μg / 100 g, vitamin B2 16 μg / 100 g, niacin (vitamin B3) 100 μg / 100 g, calcium gluconate 400 mg / 100 g) was added and then packed for storage.

[0079] (6) Sterilize the bagged infant rice cereal at 121°C under low pressure for 30 min.

[0080] Example 2:

[0081] The specific steps of making infant rice cereal are as follows:

[0082] (1) After washing the raw rice, add 1.8 times the weight of the rice into water, inoculate Lactobacillus plantarum: Saccharomyces cerevisiae in a ratio of 3:1 according to an inoculum amount of 5% of the total weight, and add 0.3% of the total weight of calcium lactate. Ferment at 30°C for 20 hours. At this time, the moisture content of the rice grains is measured to be about 70%;

[0083] (2) The fermented rice grains were dehydrated using a filter centrifuge, first centrifuged at 900 rpm for 3 min to remove surface water, and then centrifuged at 1500 rpm for 3 min. After centrifugation, the moisture content of the rice grains was measured to be about 28%;

[0084] (3) The rice grains after centrifugation were squeezed and rubbed using a two-roller machine, wherein the speed of the first roller was set to 300 rpm, the speed of the second roller was set to 1100 rpm, the gap between the rollers was 0.3 mm, the deflection angle of the two roller axes was 5°, the cold air speed was 2 m / s, and the temperature was 20°C;

[0085] (4) adding the rice powder after squeezing and rubbing into an air flow superfine grinder for superfine grinding, wherein the parameters of the air flow superfine grinder are set to a grinding pressure of 0.8 MPa and a classifying wheel speed of 3000 rpm;

[0086] (5) The ultrafinely ground rice flour was dried using a hot air flow drying device at a drying temperature of 65° C. for 15 min. The rice flour with a water content of about 30% was dried to below 14%. A nutritional supplement (ferrous sulfate 10 mg / 100 g, vitamin C 10 mg / 100 g, vitamin B1 14 μg / 100 g, vitamin B2 16 μg / 100 g, niacin (vitamin B3) 100 μg / 100 g, calcium gluconate 400 mg / 100 g) was added and then packed for storage.

[0087] (6) Sterilize the bagged infant rice cereal at 121°C under low pressure for 30 min.

[0088] Example 3:

[0089] The specific steps of making infant rice cereal are as follows:

[0090] (1) After washing the raw rice, add water twice the weight of the rice, inoculate Lactobacillus plantarum: Saccharomyces cerevisiae in a ratio of 3:1 according to an inoculum size of 5% of the total weight, and add 0.3% of calcium lactate to the total weight. Ferment at 30°C for 12 hours. At this time, the water content of the rice grains is measured to be about 70%;

[0091] (2) The fermented rice grains were dehydrated using a filter centrifuge, first centrifuged at 600 rpm for 5 min to remove surface water, and then centrifuged at 1000 rpm for 5 min. After centrifugation, the moisture content of the rice grains was measured to be about 35%;

[0092] (3) The rice grains after centrifugation were squeezed and rubbed using a two-roller machine, wherein the speed of the first roller was set to 400 rpm, the speed of the second roller was set to 1200 rpm, the gap between the rollers was 0.3 mm, the cold air speed was 2 m / s, and the temperature was 20°C;

[0093] (4) adding the rice powder after squeezing and rubbing into an air flow superfine grinder for superfine grinding, wherein the parameters of the air flow superfine grinder are set to a grinding pressure of 0.6 MPa and a classifying wheel speed of 2000 rpm;

[0094] (5) The ultrafinely ground rice flour was dried using a hot air flow drying device at a drying temperature of 65° C. for 15 min. The rice flour with a water content of about 30% was dried to below 14%. A nutritional supplement (ferrous sulfate 10 mg / 100 g, vitamin C 10 mg / 100 g, vitamin B1 14 μg / 100 g, vitamin B2 16 μg / 100 g, niacin (vitamin B3) 100 μg / 100 g, calcium gluconate 400 mg / 100 g) was added and then packed for storage.

[0095] (6) Sterilize the bagged infant rice cereal at 121°C under low pressure for 30 min.

[0096] Comparative Example 1:

[0097] The step (1) of Example 1, "adding 0.3% of the total weight of calcium lactate" was omitted, and the other steps and parameters were consistent with those of Example 1.

[0098] Comparative Example 2:

[0099] The amount of calcium lactate in step (1) of Example 1 was adjusted to 1.0%, and the other steps and parameters were consistent with Example 1.

[0100] Comparative Example 3:

[0101] The step (1) of Example 1 "inoculating Lactobacillus plantarum to Saccharomyces cerevisiae at a ratio of 3:1 at an inoculation amount of 5% of the total weight" was omitted, and the other steps and parameters were consistent with Example 1.

[0102] Comparative Example 4:

[0103] The roller grinding step (3) of Example 1 was removed, and ultrafine grinding was directly performed after centrifugal dehydration. The other steps and parameters were consistent with Example 1.

[0104] Comparative Example 5:

[0105] The parameters of the airflow superfine pulverizer in step (4) of Example 1 were set to 1.0 MPa and the classifying wheel speed to 5000 rpm. The other steps and parameters were consistent with those in Example 1.

[0106] Comparative Example 6:

[0107] The rice was crushed by a grinder to obtain coarse rice powder, and then crushed by a ball mill for 10 minutes to obtain traditional rice flour.

[0108] Result test example:

[0109] The rice flour prepared in Examples 1 to 3 and Comparative Examples 1 to 6 before adding the nutritional enhancer was subjected to performance testing. The results are shown in Table 1:

[0110] Table 1 Rice flour performance test results

[0111]

[0112]

[0113] The starch damage rate in the examples was 4.0% to 4.5%, significantly lower than that in the comparative examples. The 100-mesh sieving rate, water absorption, viscosity, whiteness, and density in the examples were all significantly improved. This indicates that the rice noodles in the examples have a good texture and strong uniformity, which positively impacts product quality in subsequent processing.

[0114] The digestibility test of the infant rice cereals prepared in Examples 1 to 3 and Comparative Examples 1 to 6 was further conducted. The results are as follows: Figures 1 to 3As shown: (1) The digestibility of infant rice flour in Examples 1 to 3 is significantly enhanced compared with that in Comparative Examples 1 to 6. The digestibility of Example 1 is the highest (mean 91.5%), and Comparative Example 4 (mean 72.1%) has the largest decrease (decreased by 19.4%), confirming the key role of physical crushing in enzymatic hydrolysis; Comparative Examples 2 and 3 have significantly decreased, highlighting the biochemical synergistic effect of calcium ions and microbial fermentation. Precise control of process parameters is the core of improving the nutritional utilization of infant rice flour. It shows that the infant rice flour prepared by this method is easier to digest than ordinary infant rice flour.

[0115] (2) Example 1 has the highest hydrolysis rate (average value of 86.8%). Its core advantage lies in the synergistic effect of 5% inoculation fermentation and 0.3% calcium lactate, combined with roller mill squeezing. Comparative Example 4 (average value of 68.1%) has the largest decrease (down 18.7%), which confirms the criticality of physical crushing to enzyme contact; Comparative Example 2 (down 16.0%) and Comparative Example 3 (down 14.2%) have decreased significantly, indicating the biochemical regulation of calcium ion concentration and microbial fermentation on hydrolysis efficiency. It shows that the infant rice flour prepared by this method is easier to hydrolyze than ordinary infant rice flour.

[0116] (3) Example 1 has the best emulsification stability (average EI of 88.2% after 15 days, and a decay rate of only 0.33% / day). The core mechanism is the synergistic stabilization effect of the calcium bridge of emulsified polysaccharides produced by microbial fermentation and 0.3% calcium lactate, combined with the amplified interfacial adsorption area by roller milling. Comparative Example 4 (EI decreased by 25.0% after 15 days) and Comparative Example 3 (decreased by 15.7%) showed significant deterioration, confirming that the synergy between physical structure destruction and biochemical emulsification is the key to delaying phase separation. The decay rate of ordinary infant rice cereal increased by 2 to 3 times, highlighting the superiority of this method in preparing infant rice cereal.

[0117] The amino acid content of the infant rice cereals prepared in Examples 1 to 3 and Comparative Examples 1 to 6 was determined. The results are shown in Table 2:

[0118] Table 2 Amino acid content of infant rice flour

[0119]

[0120]

[0121] Note: Different lowercase letters in the same row indicate significant differences (P<0.05)

[0122] The results showed that Example 1 had the highest total amino acid content (42.3±1.42 mg / g), and microbial fermentation and 0.3% calcium lactate synergistically promoted protein hydrolysis, combined with roller milling to destroy the protein-starch wrapping structure. Comparative Example 2 glutamic acid decreased by 43%, due to carboxyl-Ca 2+Precipitation; Comparative Example 4: Lysine decreased by 19% due to enzyme contact hindrance; Comparative Example 3: Methionine decreased by 18% due to phytic acid's inhibition of chelation of sulfur-containing amino acids. The infant rice cereal prepared using this method exhibits less amino acid loss and possesses greater nutritional value than commercially available ordinary rice cereal.

[0123] The embodiments provided above are not intended to limit the scope of the present invention, nor are the steps described to limit their execution order. Any obvious improvements to the present invention made by those skilled in the art in combination with existing common knowledge shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing infant rice flour with good digestibility, characterized in that: The following steps are involved: S1, washing the rice, adding water, inoculating Lactobacillus plantarum and Saccharomyces cerevisiae, adding calcium lactate, and draining the water after natural fermentation; S2, performing gradient centrifugal dehydration on the fermented rice grains using a filter centrifuge; S3, the dehydrated rice grains are squeezed and rubbed using a two-roller machine; S4, the rice powder after squeezing and rubbing is added into the air flow superfine grinding machine for superfine grinding; S5, the rice flour after ultrafine grinding is dried to obtain the rice flour with low grain breakage rate, add a nutrition enhancer, mix well and pack in bags, and sterilize after packing to obtain infant rice flour.

2. The method according to claim 1, characterized in that In step S1, the inoculation amount of brewer's yeast and lactic acid bacteria is 1% to 10%, wherein the ratio of Lactobacillus plantarum to brewer's yeast is 1 to 3:

1.

3. The method according to claim 1, characterized in that The amount of calcium lactate added in step S1 is 0.1% to 0.5%.

4. The method according to claim 1, wherein In step S2, the gradient centrifugation is first performed at 500 rpm to 1000 rpm for 2 min to 6 min, and then at 1000 rpm to 1500 rpm for 2 min to 5 min.

5. The method according to claim 1, wherein In step S3, when the two-roller machine is squeezing and rubbing, the angle between the rollers is 3° to 7°, the rotation speed of the first-level roller is set to 40rpm to 700rpm, and the rotation speed of the second-level roller is set to 400rpm to 1200rpm.

6. The method according to claim 1, characterized in that In step S3, when the two-roller machine is squeezing and kneading, a cold air flow is set between the first roller and the second roller to reduce the temperature.

7. The method according to claim 1, characterized in that In step S4, the parameters of ultrafine grinding are air flow pressure: 0.6MPa~1.0MPa, classification wheel speed 2000rpm~3000rpm, feed rate 40kg / h~60kg / h, and discharge particle size D50=48μm~150μm.

8. The method according to claim 1, characterized in that In step S5, the drying is performed using a hot air flow drying device, the drying temperature is 50° C. to 70° C., and the drying time is 1 hour to 5 hours.

9. The method according to claim 1, characterized in that Nutritional supplements include vitamins and minerals.

10. Infant rice cereal prepared by the method according to any one of claims 1 to 9.

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