A mixed-grain rice flour for infant and a preparation method thereof

Abstract

The present application relates to the field of food technology, and more particularly to a kind of mixed grain rice powder suitable for infant and its preparation method.The mixed grain rice powder is prepared by the preparation method.The preparation method comprises: mixing mixed grain and rice according to mass ratio 3:7, obtaining mixture;the mixture is subjected to warm weak acid soaking treatment, obtaining first processing material;the first processing material is vacuum packaged and subjected to ultra-high pressure cold treatment, obtaining second processing material;the second processing material is unpacked, first subjected to low-temperature drying treatment, then crushed, sieved, finally, the sieved material is added with nutrient fortifier, obtaining third processing material;the third processing material is sequentially subjected to maturation forming treatment and post-treatment, obtaining mixed grain rice powder suitable for infant.The present application can prepare mixed grain rice powder with high phytic acid degradation rate, high digestibility, long shelf life, pure flavor and high retention rate of heat-sensitive nutrients.

Description

Technical Field

[0001] This invention relates to the field of food technology, and in particular to a mixed grain rice flour suitable for infants and young children and its preparation method. Background Technology

[0002] Whole grains (such as oats, brown rice, and buckwheat) are rich in dietary fiber, minerals, and unsaturated fatty acids. However, their processing characteristics present three major bottlenecks: 1) Phytic acid is the main anti-nutritional factor in whole grains. Its high content not only combines with minerals to form insoluble complexes, reducing bioavailability, but also easily forms "phytic acid-starch / protein" complexes, which severely inhibits amylase hydrolysis; 2) The starch structure of whole grains is dense, and the content of rapidly digestible starch (RDS) is low, which reduces the digestibility and absorption rate of special populations such as infants and young children; 3) The high activity of lipases makes them prone to catalyzing the hydrolysis and oxidation of fats after wetting or crushing, resulting in a rancid taste in the product and severely shortening its shelf life.

[0003] Existing methods for removing phytic acid include traditional soaking / germination, microbial fermentation, and extrusion / heat treatment. Traditional soaking / germination requires prolonged soaking of grains at room temperature without strict control over temperature and pH, which fails to effectively stimulate endogenous phytase in the grains, resulting in a degradation rate of less than 50% for phytic acid. Furthermore, this method requires prolonged soaking at room temperature, which is not only inefficient but also prone to microbial proliferation, posing food safety risks. Microbial fermentation is difficult to standardize, has a long fermentation cycle, and produces a strong sour or fermented odor that masks the natural aroma of the grains, making it unsuitable for the high flavor requirements of infant rice cereal. Extrusion / heat treatment has limited phytic acid removal rates (<20%) and easily damages heat-sensitive nutrients (e.g., while high-temperature enzyme inactivation can deactivate lipase, it leads to vitamin B1 loss).

[0004] Existing methods for reducing lipase activity include high-temperature heat treatment and chemical antioxidant methods. While high-temperature heat treatment can effectively inactivate lipase, it also severely damages heat-sensitive nutrients in grains (such as vitamin B1, vitamin E, and glutathione). Furthermore, high temperatures cause the loss of volatile aroma compounds, resulting in a "burnt" or "cooked" taste, eliminating the natural aroma of the grains. Chemical antioxidant methods require chemical additives, which can only delay oxidation and cannot address the root cause of lipase activity problems. In addition, with consumers' increasing emphasis on "clean labels" for food (especially infant formula), the use of chemical additives is strictly limited.

[0005] Therefore, it is necessary to provide a whole grain rice cereal suitable for infants and young children and its preparation method to solve the problems of existing whole grain rice cereals, such as residual anti-nutritional factors, low digestibility, fat oxidation and rancidity, and short shelf life. Summary of the Invention

[0006] The purpose of this invention is to provide a mixed grain rice flour suitable for infants and young children, and its preparation method. The specific technical solution is as follows: In a first aspect, the present invention provides a method for preparing mixed grain rice flour suitable for infants and young children, comprising: Step S1: Mix the mixed grains and rice at a mass ratio of 3:7 to obtain a mixture; subject the mixture to a warm, weak acid soaking treatment to obtain a first treated material. The warm, weak acid soaking treatment uses a soaking solution with a pH of 5-6, a soaking temperature of 40-60℃, and a soaking time of 6-12 hours. Step S2: After vacuum packaging the first processed material, it is subjected to ultra-high pressure cold treatment to obtain the second processed material; The ultra-high pressure cold treatment uses a treatment pressure of 400~600MPa, a treatment time of 10~20min, and a treatment temperature of room temperature. Step S3: After unpacking the second processed material from the vacuum packaging, it is first dried at low temperature, then crushed and sieved, and finally, a nutrient fortifier is added to the sieved material to obtain the third processed material. Step S4: After the third processed material is subjected to a cooking and molding process and a post-processing process, a mixed grain rice flour suitable for infants and young children is obtained.

[0007] Optionally, the grains include at least one of millet, oats, brown rice, and buckwheat.

[0008] Optionally, the soaking solution used in the warm weak acid soaking treatment includes water and food-grade organic acid; the pH value of the soaking solution is adjusted to 5-6 using the food-grade organic acid.

[0009] Optionally, the food-grade organic acid includes lactic acid.

[0010] Optionally, the ratio of the mixture to the soaking solution is 1:2.5.

[0011] Optionally, the low-temperature drying process uses a drying temperature of 50℃~60℃, drying until the moisture content is <12%.

[0012] Optionally, the amount of the nutritional fortifier added shall be in accordance with the GB 10769-2025 National Food Safety Standard for Infant Cereal-Based Complementary Foods.

[0013] Optionally, the curing and molding process uses a curing temperature of 110~130℃ and a curing time of 15~25s.

[0014] Optionally, the post-processing includes sequentially crushing, cooling, and nitrogen-filling packaging the material after the curing and molding process.

[0015] In a second aspect, the present invention provides a mixed grain rice flour suitable for infants and young children, which adopts the aforementioned method for preparing mixed grain rice flour suitable for infants and young children.

[0016] The application of the technical solution of the present invention has at least the following beneficial effects: This invention provides a method for preparing mixed grain rice flour suitable for infants and young children, which can produce mixed grain rice flour with high phytic acid degradation rate, high digestibility, long shelf life, pure flavor, and high retention rate of heat-sensitive nutrients. Specifically: Regarding high phytic acid degradation rates, this invention employs a parameter-controllable warm, weakly acidic soaking treatment. This method provides a slightly acidic, temperature-appropriate environment highly compatible with the catalytic activity of endogenous phytase, promoting pre-swelling and structural dissociation of the cell walls and tightly packed protein-phytic acid-starch complexes in grains. This significantly improves substrate accessibility, thereby fully leveraging the catalytic activity of endogenous phytases and ultimately achieving a phytic acid degradation rate of over 95%. The efficient degradation of phytic acid can significantly improve the bioavailability of minerals such as calcium, iron, and zinc.

[0017] Regarding high digestibility, this invention employs ultra-high pressure cold treatment with the required parameters, which can destroy the intramolecular and intermolecular hydrogen bond network of starch molecules, promote the disintegration of the starch double helix structure, induce non-thermal physical gelatinization and porosification of starch granules, and thereby destroy their crystalline regions, significantly increasing the content of rapidly digestible starch (RDS) by 35% to 50%, greatly improving starch digestibility, and is especially suitable for infants, the elderly and other people with weak digestive functions.

[0018] Regarding extending shelf life, this invention employs ultra-high pressure cold treatment with the required parameters. This treatment disrupts non-covalent bonds such as hydrogen bonds within lipases, causing irreversible denaturation of their three-dimensional structure and deformation of the active center, thus inactivating the lipase. Simultaneously, the high-pressure treatment directly damages the cell membrane integrity of spoilage microorganisms and physically inactivates key intracellular metabolic enzymes, leading to cell lysis and death, thereby exerting a significant cold sterilization effect. This treatment eliminates lipid oxidation and microbial spoilage at the source, achieving long-term preservation without the risk of lipid oxidation and rancidity.

[0019] In terms of pure flavor and high retention rate of heat-sensitive nutrients, the present invention uses ultra-high pressure cold treatment with the required parameters to destroy the spatial structure of lipase at room temperature, thereby deactivating the lipase. In other words, lipase deactivation can be achieved without high-temperature heat treatment, perfectly preserving the natural flavor of whole grains and the heat-sensitive nutrients (such as vitamin B1, vitamin E, and glutathione) in whole grains.

[0020] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The present invention will now be described in further detail with reference to specific embodiments. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1: A method for preparing mixed grain rice cereal suitable for infants and young children, comprising: Step S1: Mix the mixed grains (specifically oats) and rice at a mass ratio of 3:7 to obtain a mixture; subject the mixture to a warm, weak acid soaking treatment to obtain a first treated material. The warm, weak acid soaking treatment uses a soaking solution with a pH of 5.5, a soaking temperature of 50°C, and a soaking time of 10 hours; the ratio of the mixed material to the soaking solution is 1:2.5; the soaking solution used is water and food-grade organic acid; the pH of the soaking solution is adjusted to 5.5 using the food-grade organic acid; the food-grade organic acid is lactic acid. Step S2: After vacuum packaging the first processed material (using a polyethylene bag), it is subjected to ultra-high pressure cold treatment to obtain the second processed material; The ultra-high pressure cold treatment uses a treatment pressure of 500 MPa, a treatment time of 15 min, and a treatment temperature of room temperature (specifically 25°C). Step S3: After unpacking the second processed material from the vacuum packaging, it is first dried at low temperature, then crushed and passed through an 80-mesh sieve, and then nutrient fortifiers such as vegetable oil, vitamins and minerals are added. The amount of nutrient fortifiers added is based on the basic nutrient indicators in 4.3 and the optional nutrient indicators in 4.4 of GB10769-2025 "National Food Safety Standard for Infant Cereal Complementary Foods" to obtain the third processed material. The low-temperature drying process uses a drying temperature of 60℃ to dry to a moisture content of <10%. Step S4: After the third processed material is subjected to a cooking and molding process and a post-processing process, a mixed grain rice flour suitable for infants and young children is obtained. The curing and molding process is completed in a roller dryer, with a curing temperature of 110~130℃ (specifically 120℃) and a curing time of 15~25s (specifically 20s).

[0023] The post-processing includes sequentially crushing, cooling, and nitrogen-filling packaging of the material after the curing and molding process.

[0024] Comparative Example 1: Unlike Example 1, the soaking temperature used in the warm weak acid soaking treatment was changed from 50°C to 25°C.

[0025] Comparative Example 2: Unlike Example 1, the warm weak acid soaking treatment was omitted, and the ultra-high pressure cold treatment was replaced with a high-temperature roasting enzyme inactivation treatment. The high-temperature roasting enzyme inactivation treatment used a roasting temperature of 150°C and a roasting time of 20 minutes.

[0026] Comparative Example 3: Unlike Example 1, the warm weak acid immersion treatment and the ultra-high pressure cold treatment are omitted.

[0027] Samples of mixed grain rice flour prepared in Example 1 and Comparative Examples 1-3 were taken and tested for phytic acid degradation rate, lipase residual activity, vitamin B1 retention rate, rapidly digestible starch (RDS) content and sensory flavor. The test results are shown in Table 1.

[0028] Phytic acid degradation rate test method: (1) Reagent preparation ① Wade colorimetric reagent: Weigh 0.15 g of ferric chloride hexahydrate (AR) and 1.5 g of sulfosalicylic acid (AR); first dissolve the ferric chloride hexahydrate in a small amount of deionized water, then add the sulfosalicylic acid and mix well. Transfer to a 500 mL volumetric flask and dilute to volume with deionized water. Store the reagent in the dark and refrigerate, and prepare immediately before use.

[0029] ② Phytic acid extract: 0.62 mol / L hydrochloric acid solution (prepared by diluting concentrated hydrochloric acid); for samples with high starch and high protein content, the solution can be adjusted to 0.5 mol / L hydrochloric acid solution.

[0030] (2) Sample extraction The sample to be tested was pulverized and passed through a 60-mesh sieve. 5.0 g of the sieved sample was accurately weighed and placed in a 50 mL capped centrifuge tube. Extraction solution was added at a material-to-liquid ratio of 1:10 (g:mL). Extraction was carried out at 25 ℃ on a shaker at 200 r / min for 3 h.

[0031] After extraction, centrifuge at 4000 r / min (approximately 2500×g) at room temperature for 10 min and collect the supernatant; set up 3 parallel experiments for each group.

[0032] (3) Sample purification AG1-X8 strong basic anion exchange resin (resin bed volume 10 mL) was used. The resin was activated, washed with water and equilibrated to a suitable pH before use.

[0033] Take the supernatant and feed it onto the column at a flow rate of 1-2 mL / min, keeping the liquid level above the resin layer throughout the process, and strictly prohibiting the column from drying out. First, rinse with 50 mL of 0.1 mol / L NaCl solution to remove impurities, then elute with 50 mL of 0.7 mol / L NaCl solution to remove phytic acid. Collect all the eluent and make up to 100 mL to obtain the purified phytic acid solution.

[0034] Note: For samples with simple matrix, the column chromatography step can be omitted. The crude extract can be diluted with deionized water and then directly measured.

[0035] (4) Color development and absorbance measurement Take 3.0 mL of phytic acid purification solution (or diluted crude extract), add 1.0 mL of Wade reagent, mix thoroughly, and let stand at room temperature in the dark for 10 min.

[0036] Using 3.0 mL deionized water + 1.0 mL Wade reagent as a blank reference, the absorbance was measured at a wavelength of 500 nm. The phytic acid content (mg / g) in the sample was calculated using the sodium phytate standard curve and the phytic acid-sodium phytate conversion factor.

[0037] (5) Calculation of phytic acid degradation rate Phytic acid degradation rate (%) = (C 初始 -C 处理后 ) / C 初始 ×100%; In the formula: C 初始 The phytic acid content of the sample before degradation treatment is expressed in mg / g; C 处理后 The remaining phytic acid content after the sample degradation treatment is shown in mg / g.

[0038] Methods for testing residual lipase activity: The determination of residual lipase activity was carried out in accordance with GB / T 5523-2008 "Grain and Oil Inspection - Determination of Lipase Activity in Grains and Oilseeds".

[0039] Methods for testing the content of rapidly digestible starch (RDS): The determination of rapidly digestible starch (RDS) content was performed in accordance with NY / T 3911-2021 "Determination of rapidly digestible starch, slow-digestible starch and resistant starch in cereals and their products by in vitro digestion method".

[0040] Sensory flavor testing methods (i.e., professional blind taste testing): (1) Establishment of the evaluation team Select 10-15 personnel with professional training in food sensory evaluation, with a balanced male-to-female ratio, no smoking or alcohol consumption, and sensitive senses of smell and taste. All evaluations will be conducted in a standard, odor-free sensory evaluation room, using independent blind testing to eliminate subjective bias.

[0041] (2) Sample preparation and mixing (simulating real-life consumption scenarios) Accurately weigh 25.0g of each of the mixed grain rice flour samples prepared in Example 1 and Comparative Examples 1-3 into a clean container, add 100mL of warm water at a temperature of 50-60℃, and stir at a uniform speed in the same direction for 1-2 minutes while adding water, so that the rice flour fully absorbs water and gelatinizes into a uniform paste. After standing and cooling to 37-40℃ (the suitable feeding temperature for infants and young children), immediately distribute to the evaluators for tasting and evaluation.

[0042] (3) Sensory evaluation criteria (out of 100 points) See the attached table. The evaluators scored the food based on four dimensions: aroma and flavor, taste and texture, solubility and consistency, and color. Flavor and taste had the highest weighting to highlight the edible characteristics of infant food.

[0043] Sensory rating criteria in the appendix

[0044] (4) Data processing All evaluation forms were collected, and after removing the highest and lowest scores, the arithmetic mean of the scores for each indicator and the total score was calculated. Higher scores indicate better sensory quality of the sample, making it more acceptable to infants and young children, and a more significant effect of processing technology on improving sensory quality.

[0045] Table 1 Test Results

[0046] From the data in Table 1, we know that: Compared to Comparative Example 1, the mixed grain rice flour prepared in Example 1 significantly improved the phytic acid degradation rate. This indicates that the warm, weakly acidic soaking treatment, using an appropriate soaking temperature, can significantly increase the activity of endogenous phytase in the mixed grains, thereby significantly improving the phytic acid degradation rate. Furthermore, in terms of lipase residual activity, the mixed grain rice flour prepared in Example 1 was significantly lower than that in Comparative Example 1. This is because, compared to the 25°C room temperature soaking in Comparative Example 1, the 50°C warm soaking in Example 1 significantly pre-swelled and softened the dense mixed grain matrix, promoting the opening of the microstructure and thus promoting starch decomposition. This facilitated the complete inactivation of lipase by ultra-high pressure cold treatment. In contrast, the mixed grain matrix soaked at room temperature in Comparative Example 1 was relatively rigid, forming a physical buffer against ultra-high pressure cold treatment, thereby limiting the decomposition of the starch crystallization zone and protecting some lipase from high pressure damage. Therefore, Comparative Example 1 exhibited higher lipase residual activity.

[0047] Compared to Comparative Example 2, the mixed grain rice flour prepared in Example 1 significantly improved the phytic acid degradation rate and vitamin B1 retention rate, and also had a rich and fragrant oat flavor. This indicates that the warm, weakly acidic soaking treatment with the required parameters in Example 1 can significantly increase the activity of endogenous phytase in the mixed grains, thereby significantly improving the phytic acid degradation rate; the ultra-high pressure cold treatment with the required parameters can destroy the spatial structure of lipase at room temperature, thus inactivating the lipase, meaning that lipase inactivation can be achieved without the high-temperature treatment in Comparative Example 2, perfectly preserving the natural flavor of the mixed grains and the retention rate of the heat-sensitive nutrient vitamin B1. In contrast, the high-temperature roasting enzyme inactivation treatment used in Comparative Example 2 not only reduced the retention rate of the heat-sensitive nutrient vitamin B1, but also caused the mixed grain rice flour to have a burnt taste; furthermore, the high-temperature roasting enzyme inactivation treatment used in Comparative Example 2 significantly reduced phytase activity, thereby significantly reducing its phytic acid degradation rate.

[0048] Compared to Comparative Example 3, the mixed grain rice flour prepared in Example 1 significantly improved the phytic acid degradation rate, achieving zero residual lipase activity, and possessed a rich and fragrant oat flavor. This indicates that the warm, weakly acidic soaking treatment with the required parameters in Example 1 can significantly increase the endogenous phytase activity in the mixed grains, thereby significantly improving the phytic acid degradation rate; the ultra-high pressure cold treatment with the required parameters can destroy the spatial structure of lipase at room temperature, causing lipase inactivation and achieving zero residual lipase activity, thus avoiding the rancid taste produced by lipase degradation of fat. In other words, the mixed grain rice flour prepared in Example 1 can retain a rich and fragrant oat flavor. In contrast, Comparative Example 3 omitted the warm, weakly acidic soaking treatment, resulting in a significant decrease in the phytic acid degradation rate; Comparative Example 3 also omitted the ultra-high pressure cold treatment, resulting in a significant increase in residual lipase activity; furthermore, the mixed grain rice flour prepared in Comparative Example 3 maintained a similar vitamin B1 retention rate as in Example 1 because Comparative Example 3 did not use ultra-high pressure treatment, but only underwent a short period of conventional drum cooking, without being subjected to the high-temperature, long-term baking as in Comparative Example 2. The ultra-high pressure cold treatment used in Example 1 is a non-thermal processing technology, which also avoids excessive thermal degradation of heat-sensitive vitamin B1. Therefore, both methods effectively reduce the destructive effect of heat on vitamin B1, exhibiting similar retention levels. Compared to Example 1, the mixed grain rice flour prepared in Comparative Example 3 contains a significantly increased content of rapidly digestible starch (RDS). This is because Comparative Example 3, without ultra-high pressure cold treatment, experienced excessive gelatinization and molecular chain breakage of its dense starch under the high temperature of the drum, resulting in almost complete conversion of the starch into rapidly digestible starch. In contrast, the ultra-high pressure cold treatment used in Example 1, under normal temperature conditions, promotes moderate hydrogen bond rearrangement (i.e., aging) of some gelatinized starch molecular chains through the physical extrusion of high pressure, forming a certain amount of slowly digestible starch (SDS). Therefore, the RDS content of the sample in Example 1 is lower than that in Comparative Example 3. This starch composition characteristic gives the product a more stable energy release characteristic, which is more conducive to healthy absorption by the gastrointestinal tract of infants and young children.

[0049] The above description is only a preferred embodiment of the present invention and does not limit the scope of the present invention. All equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the protection scope of the present invention.

Claims

1. A method for preparing mixed grain rice flour suitable for infants and young children, characterized in that, include: Step S1: Mix the mixed grains and rice at a mass ratio of 3:7 to obtain a mixture; subject the mixture to a warm, weak acid soaking treatment to obtain a first treated material. The warm, weak acid soaking treatment uses a soaking solution with a pH of 5-6, a soaking temperature of 40-60℃, and a soaking time of 6-12 hours. Step S2: After vacuum packaging the first processed material, it is subjected to ultra-high pressure cold treatment to obtain the second processed material; The ultra-high pressure cold treatment uses a treatment pressure of 400~600MPa, a treatment time of 10~20min, and a treatment temperature of room temperature. Step S3: After unpacking the second processed material from the vacuum packaging, it is first dried at low temperature, then crushed and sieved, and finally, a nutrient fortifier is added to the sieved material to obtain the third processed material. Step S4: After the third processed material is subjected to a cooking and molding process and a post-processing process, a mixed grain rice flour suitable for infants and young children is obtained.

2. The method for preparing mixed grain rice flour suitable for infants and young children as described in claim 1, characterized in that, The coarse grains include at least one of millet, oats, brown rice, and buckwheat.

3. The method for preparing mixed grain rice flour suitable for infants and young children as described in claim 1, characterized in that, The soaking solution used in the warm weak acid soaking treatment includes water and food-grade organic acid; the pH value of the soaking solution is adjusted to 5-6 using the food-grade organic acid.

4. The method for preparing mixed grain rice flour suitable for infants and young children as described in claim 3, characterized in that, The food-grade organic acids include lactic acid.

5. The method for preparing mixed grain rice flour suitable for infants and young children as described in claim 1, characterized in that, The ratio of the mixture to the soaking solution is 1:2.

5.

6. The method for preparing mixed grain rice flour suitable for infants and young children as described in claim 1, characterized in that, The low-temperature drying process uses a drying temperature of 50℃~60℃, drying until the moisture content is <12%.

7. The method for preparing mixed grain rice flour suitable for infants and young children as described in claim 1, characterized in that, The amount of the nutritional fortifier added is in accordance with GB 10769-2025, the national food safety standard for infant cereal-based complementary foods.

8. The method for preparing mixed grain rice flour suitable for infants and young children as described in claim 1, characterized in that, The curing and molding process uses a curing temperature of 110~130℃ and a curing time of 15~25s.

9. The method for preparing mixed grain rice flour suitable for infants and young children as described in claim 1, characterized in that, The post-processing includes sequentially crushing, cooling, and nitrogen-filling packaging of the material after the curing and molding process.

10. A mixed grain rice cereal suitable for infants and young children, characterized in that, The method for preparing mixed grain rice flour suitable for infants and young children as described in any one of claims 1 to 9 is adopted.

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