Preparation method of rice flour added with modifier
By adding whey protein (WPI) modifier to infant puffed rice cakes and employing mixing, centrifugation, drying, and pulverizing steps, the problem of limited improvement in gelatinization degree was solved, and rice flour with high gelatinization degree and excellent functional properties was prepared.
Patent Information
- Application Number
- CN202511759047.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-26
- Publication Date
- 2026-01-06
AI Technical Summary
Existing methods for improving the gelatinization degree of infant puffed rice cakes have limited effectiveness, and the use of traditional modifiers may lead to a decrease in gelatinization degree or abnormal viscosity, lacking clear theoretical explanations and experimental data support.
Whey protein (WPI) was used as a modifier to prepare modified rice flour through mixing, centrifugation, drying and pulverizing steps. The specific steps included mixing rice flour with WPI, centrifugation, drying and pulverizing, optimizing the gelatinization degree and viscosity, and the amount of WPI added was 3%-12% of the mass of rice flour.
It significantly improves the gelatinization degree of infant puffed rice cakes to 93%, optimizes functional properties, improves texture and enhances nutrient carrier potential, and provides a scientific explanation and theoretical basis.
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Figure CN121264594A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of food processing technology, specifically relating to the processing and manufacturing process of infant cereal foods, and in particular a method for preparing rice flour with added improvers. Background Technology
[0002] As a common complementary food for infants and young children, the digestibility and nutritional value of puffed rice crackers largely depend on the degree of starch gelatinization. The higher the degree of gelatinization, the easier it is for infants' digestive enzymes to hydrolyze the starch, thus improving the bioavailability of nutrients.
[0003] Currently, methods to improve the gelatinization degree of rice flour mainly include optimizing extrusion puffing process parameters (such as temperature, moisture, and screw speed) and adding food improvers. However, traditional process optimization methods have limited effect on improving gelatinization degree and are often accompanied by problems such as excessively hard texture or easy product aging. On the other hand, commonly used improvers such as dietary fiber or pectin, although they can improve texture, often lead to a decrease in gelatinization degree or an abnormally high viscosity, which is actually detrimental to digestion and absorption.
[0004] Whey protein (WPI) is widely used in the food industry due to its excellent emulsifying, gelling, and nutritional properties. However, research on its application as a modifier in infant puffed rice cakes to target and improve gelatinization through synergistic extrusion puffing, and the systematic elucidation of its underlying mechanisms, remains lacking. In particular, there is a lack of clear theoretical explanations and experimental data to support how WPI promotes gelatinization by influencing intermolecular forces, particle size distribution, and gelatinization properties of starch.
[0005] Therefore, there is an urgent need in this field for a new method that can effectively improve the gelatinization degree of puffed rice cakes for infants and young children, and to explore its mechanism of action in depth, so as to provide scientific basis and technical solutions for the development of high-quality, easily digestible infant cereal foods. Summary of the Invention
[0006] This invention aims to provide a method for preparing rice flour with added modifiers. It addresses the limitations of existing methods for improving the gelatinization degree of infant puffed rice cakes, and the potential for decreased gelatinization degree and abnormal viscosity when using other modifiers.
[0007] On the one hand, the present invention provides a modifier for adding to rice flour, which adopts the following technical solution: 1. A method for preparing rice flour with an additive improver, comprising the following steps: S1. Mixing and Hydration: Mix rice flour and WPI evenly in a dry state, then add water and stir continuously under heating to form a rice paste suspension; the amount of WPI added is 3%-12% of the mass of rice flour; S2. Centrifugation and collection: Centrifuge the rice paste suspension obtained in step S1, discard the supernatant, and collect the wet precipitate. S3. Drying and pulverizing: The wet precipitate obtained in step S2 is dried, and then the dried sample is pulverized and sieved to obtain high-gelatinization composite rice flour.
[0008] Preferably, the amount of WPI added in step S1 is 6% of the mass of the rice flour.
[0009] Preferably, the heating conditions in step S1 are a 90°C water bath, and the stirring time is 30 minutes.
[0010] Preferably, the centrifugation speed in step S2 is 4000 r / min and the time is 10 minutes.
[0011] Preferably, the drying in step S3 is continuous drying in a 55°C forced-air drying oven for 24 hours; the sieving is passing through a 100-mesh sieve.
[0012] On the other hand, the present invention also provides a modifier for adding to rice flour, which is obtained by the above preparation method.
[0013] Preferably, its gelatinization degree is not less than 93%.
[0014] Preferably, its peak viscosity is not higher than 920 cP and its final viscosity is not higher than 1050 cP.
[0015] The beneficial effects of this invention are that by adding an appropriate amount of whey protein (WPI), the gelatinization degree of infant puffed rice cakes can be significantly improved. At an addition of 6%, the peak gelatinization degree can reach 93%, solving the problem that traditional improvers may lead to decreased gelatinization degree or increased viscosity. Simultaneously, the modified composite rice flour exhibits comprehensive optimization in its functional properties, demonstrating excellent water and oil absorption, which helps improve the product's texture and enhance its potential as a nutrient carrier.
[0016] From a mechanistic perspective, this invention clarifies that WPI synergistically promotes gelatinization through multiple pathways, including reducing starch particle size, enhancing intermolecular hydrogen bonding, and lowering the system's gelatinization viscosity and temperature. This not only provides a clear scientific explanation for current processes but also lays a solid theoretical foundation and technological direction for the subsequent development of high-quality, easily digestible infant nutritional cereal foods. Attached Figure Description
[0017] Figure 1 The degree of gelatinization of rice flour prepared in Examples 1-4 and Comparative Examples 1-9; Figure 2 To prepare the degree of gelatinization of rice flour for comparative example 10-22; Figure 3 To measure the gelatinization degree of rice flour in comparative examples 22-34; Figure 4 The variation relationship between the degree of gelatinization and particle size of rice flour prepared in Examples 1-4 and Comparative Examples 1-9 is shown. Figure 5 To illustrate the relationship between the degree of gelatinization and particle size of rice flour prepared in Comparative Examples 10-22; Figure 6 To illustrate the relationship between the degree of gelatinization and particle size of rice flour prepared in Comparative Example 22-22; Figure 7 Analysis of the infrared properties of rice flour prepared in Examples 1-4 and Comparative Examples 1-9; Figure 8 Analysis of the infrared properties of rice flour prepared for comparative examples 10-22; Figure 9 Analysis of the infrared properties of rice flour prepared for comparative examples 22-34; Figure 10 The water absorption rate of rice flour prepared in Examples 1-4 and Comparative Examples 1-9; Figure 11 The oil absorption rate of rice flour prepared in Examples 1-4 and Comparative Examples 1-9 was determined.
[0018] Figure 12 The water absorption rate of rice flour was prepared for comparative example 10-22; Figure 13 The oil absorption rate of rice noodles was prepared as a comparative example 10-22.
[0019] Figure 14 The water absorption rate of rice flour was prepared for comparative examples 22-34; Figure 15 The oil absorption rate of rice noodles was prepared for comparative examples 22-34. Detailed Implementation
[0020] The present invention will be further described in detail below with reference to the embodiments.
[0021] Example Example 1 A method for preparing rice flour with a modifier, comprising the following preparation steps: S1. Accurately weigh 100 g of rice flour and 6 g of WPI. Mix the weighed rice flour and WPI powder evenly in a dry state. Add 1 L of deionized water. Place the beaker on a preheated magnetic stirrer and stir at a constant speed for 30 minutes in a 90°C water bath or under heating conditions to ensure that the materials are fully mixed and hydrated.
[0022] S2. Transfer the stirred rice paste suspension to centrifuge tubes and balance them on a balance. Place the centrifuge tubes in a high-speed centrifuge and centrifuge at 4000 r / min for 10 minutes. After centrifugation, carefully discard the supernatant and collect the precipitate at the bottom.
[0023] S3. Spread the wet precipitate evenly in a petri dish or weighing pan, and place it in a 55℃ forced-air drying oven for 24 hours to ensure that the moisture is completely removed. Crush the dried block sample using a grinding device and pass it through a 100-mesh sieve. Label the final sieved sample as "WPI-6% Rice Flour".
[0024] Example 2 A method for preparing rice flour with an additive improver, which differs from Example 1 in that 6 g WPI in step S1 is replaced with 3 g WPI, and the final sample is labeled as "WPI-3% rice flour". The remaining steps are the same as in Example 1.
[0025] Example 3 A method for preparing rice flour with an additive improver, which differs from Example 1 in that 6 g WPI in step S1 is replaced with 9 g WPI, and the final sample is labeled as "WPI-9% rice flour". The remaining steps are the same as in Example 1.
[0026] Example 4 A method for preparing rice flour with an additive improver, which differs from Example 1 in that 6 g WPI in step S1 is replaced with 12 g WPI, and the final sample is labeled as "WPI-12% rice flour". The remaining steps are the same as in Example 1.
[0027] Comparative Example Comparative Example 1 A method for preparing rice flour with an additive improver, which differs from Example 1 in that 6 g WPI in step S1 is replaced with 3 g CSDF, and the final sample is labeled as "CSDF-3% rice flour". The remaining steps are the same as in Example 1.
[0028] Comparative Example 2 A method for preparing rice flour with an additive improver, which differs from Example 1 in that 6 g WPI in step S1 is replaced with 4 g CSDF, and the final sample is labeled as "CSDF-4% rice flour". The remaining steps are the same as in Example 1.
[0029] Comparative Example 3 A method for preparing rice flour with an additive improver, which differs from Example 1 in that 6 g WPI in step S1 is replaced with 5 g CSDF, and the final sample is labeled as "CSDF-5% rice flour". The remaining steps are the same as in Example 1.
[0030] Comparative Example 4 A method for preparing rice flour with an additive improver, which differs from Example 1 in that 6 g WPI in step S1 is replaced with 6 g CSDF, and the final sample is labeled as "CSDF-6% rice flour". The remaining steps are the same as in Example 1.
[0031] Comparative Example 5 A method for preparing rice flour with an additive improver, which differs from Example 1 in that 6 g WPI in step S1 is replaced with 1 g SBP, and the final sample is labeled as "SBP-1% rice flour". The remaining steps are the same as in Example 1.
[0032] Comparative Example 6 A method for preparing rice flour with an additive improver, which differs from Example 1 in that 6 g WPI in step S1 is replaced with 2 g SBP, and the final sample is labeled as "SBP-2% rice flour". The remaining steps are the same as in Example 1.
[0033] Comparative Example 7 A method for preparing rice flour with an additive improver, which differs from Example 1 in that 6 g WPI in step S1 is replaced with 3 g SBP, and the final sample is labeled as "SBP3% rice flour". The remaining steps are the same as in Example 1.
[0034] Comparative Example 8 A method for preparing rice flour with an additive improver, which differs from Example 1 in that 6 g WPI in step S1 is replaced with 4 g SBP, and the final sample is labeled as "SBP4% rice flour". The remaining steps are the same as in Example 1.
[0035] Comparative Example 9 A method for preparing rice flour with added modifiers, which differs from Example 1 in that 6 g WPI is removed in step S1, and the final sample is labeled as "rice flour without additives". The remaining steps are the same as in Example 1.
[0036] Comparative Example 10 A method for preparing physically modified rice flour, the specific steps of which are as follows: S1. Grind the rice into powder and sieve it through a 100-mesh sieve. Mix the rice powder with water (solid-liquid ratio 1:10) to form a suspension.
[0037] S2. Perform high-pressure homogenization treatment at room temperature and 100 MPa, repeating twice.
[0038] S3. Centrifuge the treated rice paste at 4000 r / min for 10 min to remove excess water. Place the precipitate in a 55℃ oven for 24 h to dry. Grind the dried product and pass it through a 100-mesh sieve to obtain high-pressure homogenized rice flour. Comparative Example 11 A method for preparing physically modified rice flour differs from Comparative Example 10 in that the high-pressure homogenization cycle in step S2 is changed from 2 cycles to 4 cycles, while the remaining steps are the same as in Comparative Example 10.
[0039] Comparative Example 12 A method for preparing physically modified rice flour differs from Comparative Example 10 in that the high-pressure homogenization cycle in step S2 is changed from 2 cycles to 6 cycles, while the remaining steps are the same as in Comparative Example 10.
[0040] Comparative Example 13 A method for preparing physically modified rice flour differs from Comparative Example 10 in that the high-pressure homogenization cycle in step S2 is changed from 2 cycles to 8 cycles, while the remaining steps are the same as in Comparative Example 10.
[0041] Comparative Example 14 A method for preparing physically modified rice flour, the specific steps of which are as follows: S1. Grind the rice into powder and sieve it through a 100-mesh sieve. Mix the rice powder with water (solid-liquid ratio 1:10) to form a suspension.
[0042] S2. Perform ultrasonic treatment at a frequency of 20 kHz and a power of 150 W for 20 min at room temperature.
[0043] S3. Centrifuge the treated rice paste at 4000 r / min for 10 min to remove excess water. Place the precipitate in a 55℃ oven for 24 h. After drying, grind and pass through a 100-mesh sieve to obtain ultrasonically modified rice flour.
[0044] Comparative Example 15 A method for preparing physically modified rice flour differs from Comparative Example 14 in that the ultrasonic treatment power in step S2 is changed from 150 W to 300 W, while the remaining steps are the same as those in Comparative Example 14.
[0045] Comparative Example 16 A method for preparing physically modified rice flour differs from Comparative Example 14 in that the ultrasonic treatment power in step S2 is changed from 150 W to 350 W, while the remaining steps are the same as those in Comparative Example 14.
[0046] Comparative Example 17 A method for preparing physically modified rice flour differs from Comparative Example 14 in that the ultrasonic treatment power in step S2 is changed from 150 W to 600 W, while the remaining steps are the same as those in Comparative Example 14.
[0047] Comparative Example 18 A method for preparing physically modified rice flour, the specific steps of which are as follows: S1. Grind the rice into powder and sieve it through a 100-mesh sieve. Mix the rice powder with water (moisture content is 12%).
[0048] S2. Set the temperatures of Zone 1, Zone 2, and Zone 3 of the twin-screw extruder to 60℃, 90℃, and 130℃, respectively, and take samples when the screw speed reaches 18 Hz.
[0049] S3. The sample was placed in a 40℃ oven and dried for 24 hours. After being crushed, it was passed through a 100-mesh sieve to obtain extruded puffed rice noodles.
[0050] Comparative Example 19 A method for preparing physically modified rice flour differs from Comparative Example 18 in that the sampling time in step S2, which is 18 Hz, is changed to 21 Hz. The remaining steps are the same as those in Comparative Example 18.
[0051] Comparative Example 20 A method for preparing physically modified rice flour differs from Comparative Example 18 in that the sampling time in step S2, which is 18 Hz, is changed to 24 Hz. The remaining steps are the same as those in Comparative Example 18.
[0052] Comparative Example 21 A method for preparing physically modified rice flour differs from Comparative Example 18 in that the sampling time in step S2, which is 18 Hz, is changed to 27 Hz. The remaining steps are the same as those in Comparative Example 18.
[0053] Comparative Example 22 A method for preparing rice noodles, the specific steps of which are as follows: S1. Grind the rice and sieve it through a 100-mesh sieve to obtain rice flour.
[0054] Comparative Example 23 A method for preparing enzyme-modified rice flour, the specific steps of which are as follows: S1. After grinding rice through a 100-mesh sieve, take 300 g of the rice and add it to 1200 mL of distilled water to prepare a suspension.
[0055] S2. Heat the rice flour suspension in a constant temperature shaker at 50°C for 10 min. Add α-amylase to the rice flour suspension at a concentration of 1250 U / g.
[0056] S3. Place the prepared rice flour-enzyme suspension in a 50°C water bath constant temperature shaker and shake for 30 min. After the reaction, quickly add 6 mL of 95% ethanol to inactivate the enzyme.
[0057] S4. Centrifuge the three rice flour-enzyme suspensions at 4000 rpm for 10 min in a centrifuge, discard the supernatant, collect the starch-containing precipitate, and dry it at 40℃ for 48 h to obtain α-amylase modified rice flour.
[0058] Comparative Example 24 A method for preparing enzyme-modified rice flour differs from Comparative Example 23 in that the concentration of α-amylase in step S2 is changed from 1250 U / g to 1250 U / g, while the remaining steps are the same as in Comparative Example 23.
[0059] Comparative Example 25 A method for preparing enzyme-modified rice flour differs from Comparative Example 23 in that the concentration of α-amylase in step S2 is changed from 1250 U / g to 1750 U / g, while the remaining steps are the same as in Comparative Example 23.
[0060] Comparative Example 26 A method for preparing enzyme-modified rice flour differs from Comparative Example 23 in that the concentration of α-amylase in step S2 is changed from 1250 U / g to 2000 U / g, while the remaining steps are the same as in Comparative Example 23.
[0061] Comparative Example 27 A method for preparing enzyme-modified rice flour differs from Comparative Example 23 in that, in step S2, the addition of α-amylase with a final concentration of 1250 U / g is replaced with saccharifying enzyme with a final concentration of 1250 U / g, and saccharifying enzyme-modified rice flour is finally obtained. The remaining steps are the same as those in Comparative Example 23.
[0062] Comparative Example 28 A method for preparing enzyme-modified rice flour differs from Comparative Example 23 in that, in step S2, the α-amylase with a final concentration of 1250 U / g is replaced with a saccharifying enzyme with a final concentration of 1500 U / g, and saccharifying enzyme-modified rice flour is finally obtained. The remaining steps are the same as those in Comparative Example 23.
[0063] Comparative Example 29 A method for preparing enzyme-modified rice flour differs from Comparative Example 23 in that, in step S2, the α-amylase with a final concentration of 1250 U / g is replaced with a saccharifying enzyme with a final concentration of 1750 U / g, and saccharifying enzyme-modified rice flour is finally obtained. The remaining steps are the same as those in Comparative Example 23.
[0064] Comparative Example 30 A method for preparing enzyme-modified rice flour differs from Comparative Example 23 in that, in step S2, the α-amylase with a final concentration of 1250 U / g is replaced with a saccharifying enzyme with a final concentration of 2000 U / g, and saccharifying enzyme-modified rice flour is finally obtained. The remaining steps are the same as those in Comparative Example 23.
[0065] Comparative Example 31 A method for preparing enzyme-modified rice flour differs from Comparative Example 23 in that, in step S2, the α-amylase with a final concentration of 1250 U / g is replaced with maltose amylase with a final concentration of 1250 U / g, and maltose amylase-modified rice flour is finally obtained. The remaining steps are the same as those in Comparative Example 23.
[0066] Comparative Example 32 A method for preparing enzyme-modified rice flour differs from Comparative Example 23 in that, in step S2, the α-amylase with a final concentration of 1250 U / g is replaced with maltose amylase with a final concentration of 1500 U / g, and maltose amylase-modified rice flour is finally obtained. The remaining steps are the same as those in Comparative Example 23.
[0067] Comparative Example 33 A method for preparing enzyme-modified rice flour differs from Comparative Example 23 in that, in step S2, the α-amylase with a final concentration of 1250 U / g is replaced with maltose amylase with a final concentration of 1750 U / g, and maltose amylase-modified rice flour is finally obtained. The remaining steps are the same as those in Comparative Example 23.
[0068] Comparative Example 34 A method for preparing enzyme-modified rice flour differs from Comparative Example 23 in that, in step S2, the α-amylase with a final concentration of 1250 U / g is replaced with maltose amylase at a final concentration of 2000 U / g, and maltose amylase-modified rice flour is finally obtained. The remaining steps are the same as those in Comparative Example 23.
[0069] Test case Test Example 1 The rice flour obtained in Examples 1-4 and Comparative Examples 1-34 was subjected to gelatinization degree determination. 1 g of each sample passed through a 100-mesh sieve was weighed and placed in separate 150 mL stemmed beakers, labeled M1 and M2. A separate stemmed beaker without any sample was used as a blank control, labeled M0. 50 mL of distilled water was added to each of the three beakers, M0, M1, and M2, and the mixture was shaken well. M1 was heated on an electric stove and kept at a gentle boil for 20 min, then cooled to room temperature. Then, 5 mL of 3% saccharifying enzyme solution (freshly prepared) was added to each of the three beakers, and the mixture was stirred well and placed in a 37°C constant temperature water bath with continuous stirring for 2 h. After removal, 2 mL of 1 mol hydrochloric acid was added to each of the three beakers, and the volume was then adjusted to 100 mL with distilled water. After centrifugation, take 10 mL of the supernatant from each flask and place it in a 100 mL wide-mouth conical flask. Add 20 mL of 0.1 mol / L iodine solution and 18 mL of 0.1 mol / L NaOH solution sequentially, and place in the dark for 15 min. Then, add 2 mL of 10% sulfuric acid to each of the three flasks and titrate with 0.1 mol / L Na₂S₂O₂ solution until colorless. Record the volumes of Na₂S₂O₂ solution consumed during titration as V₀, V₁, and V₂, respectively. Calculate the degree of gelatinization using the formula.
[0070]
[0071] In the formula, V0, V1, and V2 are the volumes of sodium thiosulfate consumed during the titration of M0, M1, and M2, respectively, in mL.
[0072] like Figure 1 As shown, with the increase of the modifier content, the gelatinization degree of all three modifiers showed a trend of first increasing and then decreasing, with significant differences. The addition of WPI showed a non-linear correlation with the gelatinization degree. When the WPI addition was 6%, the gelatinization degree of the rice flour system reached a peak of 93%, which was significantly higher than that of the unmodified rice flour sample. P <0.05). However, when the WPI concentration increased to 8% and 10%, the gelatinization degree showed a decreasing trend, accompanied by a decrease in system stability. When the CSDF addition was 5%, the gelatinization degree of the rice flour system reached 92%. As the CSDF addition continued to increase, the gelatinization degree decreased to 88%. With the gradual increase of the SBP addition, the gelatinization degree first increased to 84% and then rapidly decreased to 77%.
[0073] like Figure 2 As shown, with the increase of homogenization cycles, the degree of gelatinization of the samples showed a significant positive correlation (p<0.05), eventually reaching as high as 92%. The shear force and frictional heat generated by the screw during extrusion puffing had a certain impact on the degree of gelatinization of the rice flour. At screw speeds of 18-21 Hz, the degree of gelatinization was below 90%, increasing to 91% at 24 Hz, and then rapidly decreasing at 27 Hz. When the ultrasonic power increased to 300 W, the degree of gelatinization showed a trend of first increasing and then decreasing, eventually dropping to 74%.
[0074] like Figure 3 As shown, treatments with α-amylase, saccharifying enzyme, and maltodextrin all significantly affected the gelatinization degree of rice flour. The gelatinization degree in the α-amylase-treated group showed a significant negative correlation with enzyme activity. The addition of saccharifying enzyme resulted in a higher overall gelatinization degree than pure rice flour, but increased activity did not significantly change the gelatinization degree, and it remained below 90% overall.
[0075] Test Example 2 The rice flour prepared in Examples 1-4 and Comparative Examples 1-34 was subjected to particle size analysis. 0.5 g of sample was weighed and placed in a conical flask containing 10 mL of deionized water. The sample was ultrasonically treated for 30 min and then scanned in the measurement range of (0.1~5000 nm) using a laser particle size analyzer.
[0076] like Figure 4 As shown, increasing the amount of WPI initially decreased the particle size, then increased it. Conversely, the introduction of CSDF did not significantly alter the particle size distribution. Among these, the introduction of SBP exhibited a unique concentration dependence, with its particle size increasing significantly with increasing concentration. Further analysis confirmed that the addition of an appropriate amount of WPI can reduce the particle size, thereby increasing the degree of gelatinization.
[0077] like Figure 5As shown, all three physical modification methods—high-pressure homogenization, extrusion puffing, and ultrasonic treatment—significantly refined the particle size of rice flour, but the different treatment methods exhibited different patterns. After eight cycles of high-pressure homogenization, the average particle size of the rice flour significantly decreased from 1805.33 ± 103.35 nm in pure rice flour to 597.56 ± 17.32 nm. P <0.05), indicating good mechanical crushing effect. During extrusion puffing, the particle size change exhibited a non-linear characteristic of first decreasing and then increasing. The minimum particle size of 702.33±7.23 nm was obtained when the screw speed was 21 Hz, a decrease of approximately 61.12% compared to the initial value. However, when the speed was increased to 27 Hz, the particle size increased again to 1033.53±65.72 nm. Under ultrasonic modification, the overall particle size showed a decreasing trend, reaching a minimum of 1460.66±107.67 nm at 450 W, and increasing to 1507.96±23.74 nm at 600 W. The particle size distribution of the ultrasonically treated group showed an overall decreasing trend, reaching a minimum of 1460.66±107.67 nm under 450 W treatment conditions, a decrease of approximately 23.41% compared to the control group. However, when the ultrasonic power was increased to 600 W, the particle size rebounded to 1507.96±23.74 nm (p>0.05).
[0078] like Figure 6 As shown, different amylase treatments had significant effects on the particle size of rice flour. α-Amylase activity showed a non-linear correlation with particle size change, exhibiting a trend of first decreasing and then increasing. However, the particle size of rice flour after saccharification and enzymatic hydrolysis gradually decreased with increasing activity, while maltose amylase showed a slight decrease in particle size.
[0079] Test Example 3 The rice flours prepared in Examples 1-4 and Comparative Examples 1-34 were subjected to Fourier transform infrared spectroscopy (FT-IR) measurements. The powders were placed on the sample holder of the FT-IR spectrometer, and the instrument was set to scan 32 times with a resolution of 4 cm⁻¹. -1 , in 400-4000 cm -1 The sample was scanned within the specified wavelength range to acquire infrared spectra.
[0080] like Figure 7 As shown, each modifier affects the structural properties of starch through specific molecular mechanisms. With the addition of WPI, the peak in the 3600-3200 cm⁻¹ region shifts to lower frequencies, indicating an increase in intermolecular hydrogen bonds (OH and N- bonds) and a gradual increase in intermolecular forces. With the increase of CSDF, the stretching vibration of the OH bonds is observed at 3300 cm⁻¹. -1An increase in the half-peak width (WHM) of the OH bond stretching vibration absorption peak was observed. This is due to the hydrophilicity of soluble dietary fiber, which increases the mobility of starch chains and promotes their rearrangement. When the pectin content increased from 1% to 4%, the characteristic absorption peak increased from 3182 cm⁻¹. -1 Migrate to 3285cm -1 Introducing SBP can promote the increase of hydrogen bond cross-linking strength in starch, thereby increasing starch viscosity and inhibiting water absorption and gelatinization.
[0081] like Figure 8 As shown, the infrared spectra of starch treated by the three modification methods did not show any new characteristic absorption peaks, and the positions of each characteristic peak did not shift significantly (3339.4 cm⁻¹). -1 The main peak remained stable. This indicates that physical modification did not alter the basic chemical bond structure of starch molecules; its mechanism of action primarily manifested in changes to the physical structure. The mean peak value was approximately 3300 cm⁻¹ after treatment. -1 The characteristic absorption peaks representing the OH stretching vibration all showed a blue shift after processing. This shift was significantly correlated with the change in the intensity of hydrogen bonding, indicating that all three modification methods weakened the hydrogen bonding between starch molecular chains, thereby further affecting the starch's ability to bind with water and thus accelerating the gelatinization process.
[0082] like Figure 9 As shown, although the breaking of the molecular structure releases some new hydroxyl groups, due to the presence of short-chain structures, the total number of free hydroxyl groups in some enzymatic hydrolysis products is less than that of the original starch. After the starch chains were broken by three enzymes, the 300-3500 cm⁻¹ -1 The OH stretching vibration peaks at [value missing] broadened or increased in intensity, due to increased exposure of hydroxyl groups (-OH). The figure shows that with increasing enzymatic concentration, the peak at 1022 cm⁻¹ in the infrared spectrum [value missing]. -1 The peak spectrum gradually intensifies.
[0083] As shown in Table 1, when 4% and 6% WPI were added, the disorder index of the starch system increased to 0.994±0.005 and 1.002±0.004, respectively. The composite system containing CSDF and pectin showed a higher degree of order, indicating that CSDF and SBP can form a relatively stable arrangement with starch, making it more prone to aging after gelatinization and affecting the overall digestibility of rice flour.
[0084] Table 1. Starch ordering degree of rice flour obtained in Examples 1-4 and Comparative Examples 1-9
[0085] As shown in Table 2, after four high-pressure homogenizations and 24 Hz extrusion treatments, the disorder of the starch system significantly decreased to 1.006±0.003 and 1.002±0.003 ( ). P<0.05). This may be because the crystalline structure of starch granules is destroyed after the high-pressure homogenization process. The originally ordered molecular chains are broken up or rearranged, and the original structure of starch granules is destroyed by strong mechanical force, especially the molecular arrangement in the crystalline region.
[0086] Table 2. Degree of starch ordering in rice flour prepared in Comparative Examples 10-22
[0087] As shown in Table 3, the hydrolysis of glycosidic bonds leads to the breakage of the long-chain structure of starch, thereby disrupting the crystalline regions. This typically results in a decrease in the overall orderliness of starch, transforming it into a more disordered and amorphous structure. Enzymatic hydrolysis is usually accompanied by a significant decrease in molecular weight. The large starch molecules are converted into smaller sugar molecules or oligosaccharides through enzymatic hydrolysis, which affects the structure of its molecular chains. The weaker intermolecular forces between short-chain molecules lead to a decrease in the orderliness of starch.
[0088] Table 3. Degree of starch ordering in rice flour prepared in Comparative Examples 22-34
[0089] Test Example 4 The gelatinization characteristics of the rice flour prepared in Examples 1-4 and Comparative Examples 1-34 were determined using a rapid viscosity analyzer (RVA). 3 g of sample rice flour (with a moisture content of 14%) was taken, mixed with 25 mL of distilled water in an RVA-specific aluminum container, and the RVA was used to measure the gelatinization characteristics using the Standard 1 program. Each sample was repeated three times. The specific test procedure was as follows: 50°C for 1 min, then increased to 95°C at a rate of 5°C / min (9 min), held at 95°C for 7 min, decreased to 50°C at a rate of 6°C / min (7.5 min), held at 50°C for 4.5 min, with an initial stirrer speed of 960 r / min for the first 10 s, followed by a speed of 160 r / min.
[0090] As shown in Table 4, the peak viscosity, final viscosity, and gelatinization temperature of rice flour with added WPI and CSDF were all lower than those of pure rice flour. The lowest peak viscosity (917.00±10.07 cP) was observed with the addition of 6% WPI, while the final viscosity, setback value, and gelatinization temperature were 1049.00±37.44 cP, 486.00±20.03 cP, and 79.60±1.49℃, respectively, with the addition of 8% WPI. The addition of CSDF effectively reduced the disintegration value of the rice flour to 147.66±39.00 cP. However, the addition of SBP resulted in higher peak viscosity, final viscosity, and gelatinization temperature than pure rice flour. The addition of 4% SBP resulted in peak viscosity and gelatinization temperature reaching 4064.00±64.81 cP and 90.66±0.88 cP, respectively.
[0091] Table 4. Gelatinization characteristics of rice flour prepared in Examples 1-4 and Comparative Examples 1-9
[0092] As shown in Table 5 below, it can be seen that all three physical modification methods effectively reduced the peak viscosity, final viscosity, retrogradation value, and gelatinization temperature of rice flour. Among them, the peak viscosity of homogenized secondary modification was as low as 262.00±6.65 cP. At this time, the particle breakage degree was low, the effective surface area was small, and the intermolecular interaction was weak, resulting in a low viscosity. This indicates that there are undispersed agglomerates in the system at this time, and the energy is dispersed to the local area during shearing, which cannot effectively form a uniform viscous structure
[107] . The peak viscosity, retrogradation value, and gelatinization temperature of rice flour under extrusion at 24 Hz were as low as 263.66±5.92 cP, 49.33±6.88 cP, and 51.09±0.54℃, respectively. This indicates that at 24 Hz, the screw speed is faster, the shear force is stronger, and the starch particles and molecular chains are subjected to more intense mechanical action. This may be because the long chain breaks down to form short chain dextrin, which weakens the water absorption and swelling capacity of starch, thereby reducing the peak viscosity.
[0093] Table 4. Gelatinization characteristics of rice flour prepared in Comparative Examples 10-22
[0094] As shown in Table 3-6 below, it can be seen that with the increase of α-amylase concentration, the peak viscosity first decreases and then increases from 1674.67±10.60 cP to 1887.33±2.08 cP, and the disintegration value decreases significantly with the increase of concentration. With the increase of saccharifying enzyme concentration, the disintegration value fluctuates greatly, but is generally higher than that of the α-amylase group. This phenomenon is similar to the study by Gui et al.
[123] , which indicates that this phenomenon is related to the different action mechanism of saccharifying enzyme. The addition of maltose amylase makes the gelatinization temperature as low as 71.83℃, indicating that enzymatic hydrolysis reduces the gelatinization initiation temperature of starch.
[0095] Table 4. Gelatinization characteristics of rice flour prepared in Comparative Examples 22-34
[0096] Test Example 5 The rice flour prepared in Examples 1-4 and Comparative Examples 1-34 were analyzed for water absorption and oil absorption. Oil absorption rate: 1g of rice flour (m1) was mixed with 10mL of corn oil and stirred at room temperature for 30 min. The mixture was then transferred to a centrifuge tube (m0) and centrifuged at 3000 r / min for 5 min. The oil was discarded, and the centrifuge tube was inverted for a period of time to allow the oil to flow down. After wiping the oil off the tube wall, the centrifuge tube was weighed (m2). The oil absorption rate (OA) was calculated according to the following formula. The test was performed in parallel three times.
[0097] OA(%)=(m2-m0-m1) / m1×100 Water absorption rate: Mix 1 g of corn starch or porous starch (m1) with 10 mL of deionized water, stir at room temperature for 30 min, transfer the mixture to a centrifuge tube (m0) and centrifuge at 8000 r / min for 5 min. After discarding the water and wiping the tube wall clean, weigh the centrifuge tube (m2) and calculate the water absorption rate (WA) according to the following formula. Perform three parallel measurements.
[0098] WA(%)=(m2-m0-m1) / m1×100 like Figure 10 As shown, the water absorption rate of all three improvers showed a significant upward trend. Among them, WPI had a higher overall water absorption rate than the other two improvers, with its water absorption rate gradually increasing to 113.8 ± 1.11%. This indicates that rice flour with added WPI has a strong water absorption capacity.
[0099] like Figure 11 As shown, WPI exhibited the best oil adsorption performance among the three modifiers. At a 1% addition level, its oil absorption rate was significantly higher than the other two modifiers, reaching 160.1±3.64%, an increase of 23.75% compared to the control group. In contrast, CSDF showed lower water and oil absorption capacities than WPI when added; while SBP's effect on the oil absorption rate of the composite starch system showed a significant concentration-dependent characteristic. When the addition level reached 3%, the system's oil absorption rate peaked at 126.7±1.63%, subsequently decreasing to 123.9±2.11% with further increases in addition.
[0100] from Figure 12-13 It can be seen that different physical treatment methods have different effects on starch water absorption. Among the three physical modification methods, homogenization and extrusion puffing showed significant improvements in water absorption. In particular, the water absorption rate of the 24Hz extrusion treatment group reached the highest, reaching 120.9±3.02%, which was significantly better than the other methods, while the water absorption rate of 600 W ultrasound decreased to 118.3±2.47%.
[0101] like Figure 14-15 As shown, after treatment with α-amylase, maltose amylase, and saccharifying enzyme, the water absorption rate and oil absorption rate of rice flour exhibited a non-linear trend of first increasing and then decreasing. Experimental data showed that when the concentration of α-amylase and maltose amylase reached 1750 U / mL, the water absorption rate reached its peak values of 112.6±3.02% and 108.9±2.56%, respectively. In contrast, saccharifying enzyme showed its maximum water absorption rate of 109.4±3.04% at 1500 U / mL, indicating that different enzyme systems may have specific differences in their action sites on the substrate.
[0102] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.
Claims
1. A method for preparing an improved rice flour with an additive, characterized by, The method comprises the following steps: S1, mixing and hydrating: uniformly mixing rice powder and WPI in a dry state, then adding water, continuously stirring under heating conditions to form a rice paste suspension; wherein the added amount of WPI is 3%-12% of the mass of rice powder; S2, centrifugation and collection: centrifuging the rice paste suspension obtained in step S1, discarding the supernatant, and collecting the wet precipitate; S3, drying and crushing: drying the wet precipitate obtained in step S2, then crushing and sieving the dried sample to obtain a high-gelatinization composite rice powder.
2. The method for preparing a modified agent-added rice flour according to claim 1, characterized in that, In step S1, the added amount of WPI is 6% of the mass of rice powder.
3. The method of claim 1, wherein the modified rice flour is prepared by adding the modifier to the rice flour. In step S1, the heating condition is a 90℃ water bath, and the stirring time is 30 minutes.
4. The method of claim 1, wherein the modified rice flour is prepared by adding the modifier to the rice flour. In step S2, the centrifugation speed is 4000 r / min, and the time is 10 minutes.
5. The method of claim 1, wherein the modified rice flour is prepared by adding the modifier to the rice flour. In step S3, the drying is continuous drying in a 55℃ air-drying oven for 24 hours; the sieving is through a 100-mesh sieve.
6. A high-gelatinization composite rice powder prepared by the method of any one of claims 1-5.
7. The high degree of gelatinization composite rice flour according to claim 6, characterized in that, The gelatinization degree thereof is not less than 93%.
8. The high degree of gelatinization composite rice flour according to claim 6, characterized by, The peak viscosity thereof is not higher than 920 cP, and the final viscosity is not higher than 1050 cP.