Crisp noodle compound powder and application thereof in preparation of low-digestibility crisp noodles

Abstract

The invention provides compound flour of crisp noodles and application of the compound flour in preparation of low-digestibility crisp noodles, and belongs to the technical field of crisp noodles. The compound flour of the crisp noodles provided by the invention is prepared from 70%-90% of wheat flour and 10%-30% of a potato starch-rice peptide compound, the potato starch-rice peptide compound comprises the following raw materials: rice peptide and potato starch in a mass ratio of (1.5-2): 10. The potato starch-rice peptide compound is used as a raw material to partially replace wheat flour for compounding, so that the pasty viscosity of the compound flour for the crisp noodles is remarkably reduced, and the texture characteristics of dough and the crisp noodles are changed. After the potato starch-rice peptide compound is added, the content of RDS is reduced to 41.21% from 86.26%, the content of SDS is increased to 13.18% from 8.32%, and the content of RS is increased to 47.01% from 5.42%; the eGI (enhanced gradient index) value is reduced to 59.12 from 108.09.

Description

Technical Field

[0001] This invention belongs to the field of crispy noodle technology, specifically relating to a crispy noodle compound powder and its application in the preparation of low-digestibility crispy noodles. Background Technology

[0002] Instant noodles are convenient, ready-to-eat foods made primarily from wheat flour and other grains, processed through dough preparation, rolling or extrusion molding, steaming, and frying / drying. Crispy noodles are a type of instant noodle, popular among consumers for their crispy texture, convenience, and reasonable price. However, most crispy noodles on the market are high in glycemic index (GI). Long-term consumption of high-GI foods may lead to obesity, type 2 diabetes, and cardiovascular diseases. Therefore, low-GI foods are gaining importance due to their ability to effectively control post-meal blood sugar spikes. Currently, with the emphasis on high-quality and low-sugar healthy eating, it is crucial to control energy intake to maintain ideal weight while also considering nutritional health benefits. Consuming low-digestibility starch-based foods can maintain stable blood sugar levels and help reduce the risk of type 2 diabetes, obesity, coronary heart disease, hypertension, and other chronic diseases. Therefore, there is an urgent need to develop low-GI, low-digestibility crispy noodles with good slow or resistant digestion.

[0003] Most commercially available instant noodles are deep-fried. Because starch combines with oil to form starch-lipid complexes, deep-fried instant noodles are less digestible than non-deep-fried ones. Non-deep-fried instant noodles, as a new and healthier product, represent another goal of the healthy transformation of instant noodles by reducing oil content. With rising living standards and health awareness, more and more people are choosing non-deep-fried instant noodles. Therefore, developing a non-deep-fried, low-digestibility instant noodle that caters to new consumer preferences has significant research value and market potential. Summary of the Invention

[0004] In view of this, one of the objectives of the present invention is to provide a dry noodle compound powder with low GI and low digestibility.

[0005] The second objective of this invention is to provide a non-fried crispy noodle with low GI and low digestibility.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a dry crispy noodle compound powder, which is composed of the following raw materials in the following mass percentages: 70% to 90% wheat flour, 10% to 30% potato starch-rice peptide complex; the raw materials of the potato starch-rice peptide complex include rice peptide and potato starch, and the dry basis mass ratio of the rice peptide and potato starch is 1.5 to 2:10.

[0008] Preferably, the preparation method of the potato starch-rice peptide complex includes the following steps: mixing rice peptides and potato starch, adding water to the mixture until the moisture content is 30% to 40%, sealing and placing at room temperature, then drying, pulverizing and sieving, and reacting at 95℃ to 105℃ for 17h to 19h to obtain the potato starch-rice peptide complex.

[0009] Preferably, the time for sealing at room temperature is 3.5 to 4.5 hours.

[0010] Preferably, the drying temperature is 35℃~45℃, and the drying time is 11h~13h.

[0011] Preferably, the sieve mesh size is 100 mesh.

[0012] The present invention also provides the application of the above-mentioned dry noodle compound powder in the preparation of low-GI and / or low-digestibility foods.

[0013] The present invention also provides a low-GI and / or low-digestibility crispy noodle, made from the above-mentioned crispy noodle compound powder.

[0014] The present invention also provides a method for preparing the above-mentioned crispy noodles, comprising the following steps: mixing the crispy noodle compound powder with water and kneading it into a dough, shaping the dough into noodles, and baking them to obtain crispy noodles.

[0015] Preferably, the baking temperature is 170℃~190℃, and the baking time is 25min~35min.

[0016] The beneficial effects of this invention are:

[0017] This invention uses potato starch-rice peptide complex as a raw material to partially replace wheat flour in the compounding process, which can significantly reduce the paste viscosity of the instant noodle compound powder and change the textural properties of the dough and instant noodles. After adding potato starch-rice peptide complex, the content of RDS (rapidly digestible starch) decreased from 86.26% to 41.21%, while the contents of SDS (slowly digestible starch) and RS (resistant starch) increased from 8.32% to 13.18% and from 5.42% to 47.01%, respectively; the eGI (predicted glycemic index) value decreased from 108.09 to 59.12.

[0018] The dry noodle compound powder provided by this invention offers a new option for the raw material source of developing personalized, nutritious, and healthy low-digestibility, low-GI baked foods. Attached Figure Description

[0019] Figure 1 Viscosity curves of potato starch and rice peptide complexes with different contents;

[0020] Figure 2 X-ray diffraction patterns of potato starch complexes with different amounts of rice peptides;

[0021] Figure 3 Gelatinization curves of H-RPT-20 mixed with wheat flour in different proportions;

[0022] Figure 4 Hydrolysis rate curves of H-RPT-20 on crispy noodles with different substitution ratios. Detailed Implementation

[0023] This invention provides a dry crispy noodle compound powder, which is composed of the following raw materials in the following mass percentages: 70% to 90% wheat flour, 10% to 30% potato starch-rice peptide complex; the raw materials of the potato starch-rice peptide complex include rice peptide and potato starch, and the dry basis mass ratio of the rice peptide and potato starch is 1.5 to 2:10.

[0024] This invention does not specifically limit the sources of wheat flour, potato starch, and rice peptides. In this invention, the mass percentage of wheat flour in the dry noodle compound powder can be selected from 70%, 75%, 80%, 85%, and 90%, and the mass percentage of the potato starch-rice peptide complex in the dry noodle compound powder can be selected from 30%, 25%, 20%, 15%, and 10%. In this invention, the potato starch-rice peptide complex is made from rice peptides and potato starch, and the mass ratio of rice peptides and potato starch, on a dry basis, can be selected from 1.5:10, 1.6:10, 1.7:10, 1.8:10, 1.9:10, and 2:10.

[0025] In this invention, the preferred method for preparing the potato starch-rice peptide complex includes the following steps: mixing rice peptides and potato starch, adding water until the moisture content of the mixture is 30% to 40%, sealing and placing at room temperature, then drying, pulverizing and sieving, and reacting at 95°C to 105°C for 17 to 19 hours to obtain the potato starch-rice peptide complex.

[0026] In this invention, the moisture content of the mixture is preferably 32%–38%, more preferably 34%–36%; the time for sealing and placing at room temperature is preferably 3.5h–4.5h, more preferably 3.8h–4.2h. In this invention, the drying temperature is preferably 35℃–45℃, more preferably 38℃–42℃; the drying time is preferably 11h–13h, more preferably 11.5h–12.5h. This invention does not have a specific limitation on the pulverization method; conventional pulverization methods in the art can be used. In this invention, the mesh size of the sieve is preferably 100 mesh. In this invention, after pulverization and sieving, a high-temperature reaction is carried out. The temperature of the high-temperature reaction is preferably 96℃–102℃, more preferably 98℃–100℃, and the time of the high-temperature reaction is preferably 17.5h–18.5h, more preferably 17.9h–18.2h.

[0027] This invention also provides the application of the above-mentioned crispy noodle compound powder in the preparation of low-GI and / or low-digestibility foods. In this invention, the food preferably includes baked goods, and the baked goods preferably include crispy noodles.

[0028] The present invention also provides a low-GI and / or low-digestibility crispy noodle, made from the above-mentioned crispy noodle compound powder.

[0029] The present invention also provides a method for preparing the above-mentioned crispy noodles, comprising the following steps: mixing the crispy noodle compound powder with water and kneading it into a dough, shaping the dough into noodles, and baking them to obtain crispy noodles.

[0030] This invention does not have a specific limitation on the ratio of the compound powder to water for crispy noodles, as long as it can be kneaded into a dough. In this invention, after kneading the dough, it is preferably first pressed into sheets, and then made into noodles. The noodles are preferably round noodles, and the diameter of the round noodles is preferably 2 mm. In this invention, the baking temperature is preferably 170℃~190℃, more preferably 175℃~185℃, and the baking time is preferably 25min~35min, more preferably 28min~32min.

[0031] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0032] Unless otherwise specified, the following embodiments are all conventional methods.

[0033] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0034] The rice peptides in the following examples are food grade and were purchased from Xi'an Lvruquan Biotechnology Co., Ltd.

[0035] Each experiment described below was performed in triplicate, and results are expressed as mean ± SD. Data processing, statistical analysis, and graphing were performed using Excel, SPSS 23, and Origin software. One-way ANOVA and Tukey's post-hoc test were used to determine differences between samples. Significant differences between two groups were indicated by different letters (P < 0.05).

[0036] Example 1

[0037] A type of dry noodle compound powder is composed of the following raw materials in the following mass percentages: 80% wheat flour and 20% potato starch-rice peptide complex; wherein the raw materials of the potato starch-rice peptide complex include rice peptide and potato starch, and the rice peptide and potato starch are in a dry basis mass ratio of 2:10.

[0038] The preparation method of the potato starch-rice peptide complex is as follows: rice peptides and potato starch are mixed evenly and placed in a transparent petri dish. Water is sprayed in to make the moisture content 35%. After stirring evenly, the mixture is covered with plastic wrap and equilibrated at room temperature for 4 hours. The equilibrated sample is then dried in a 40°C oven for 12 hours. Subsequently, the sample is pulverized and passed through a 100-mesh sieve, and then transferred to a reaction vessel. The mixture is reacted in a 100°C oven for 18 hours to obtain the potato starch-rice peptide complex (the potato starch-rice peptide complex is labeled as H-RPT-20).

[0039] Example 2

[0040] Rice peptides and potato starch were mixed at a dry weight ratio of 0:10 (labeled as H-RPT-0 or PS). control Potato starch-rice peptide complexes were prepared in ratios of 0.5:10 (labeled as H-RPT-5 or PS+5%), 1:10 (labeled as H-RPT-10 or PS+10%), 1.5:10 (labeled as H-RPT-15 or PS+15%), and 2:10 (labeled as H-RPT-20 or PS+20%), respectively. The specific preparation method of the potato starch-rice peptide complex was the same as in Example 1. Native potato starch was used as a blank control sample (labeled as PS or PS+20%). native The following tests were performed:

[0041] (1) The swelling degree of potato starch-rice peptide complexes in different groups was tested. The specific testing methods are as follows:

[0042] Weigh 0.2 g of sample (dry basis) into a 15 mL centrifuge tube, add deionized water to prepare a 10% (w / w) starch emulsion, and magnetically stir (500 r / min, 30 min) in a constant temperature water bath at 60℃, 70℃, 80℃, and 90℃ respectively. After centrifugation (4000 r / min, 15 min), discard the supernatant. The expansion degree of the sample is calculated according to the following formula:

[0043]

[0044] In the formula: m1 is the mass of the expanded sample (g); m2 is the dry basis mass of the sample (g).

[0045] The results are shown in Table 1. The swelling degree of all starch samples increased with increasing temperature. Compared with PS, the swelling degree of H-RPT-0 was significantly reduced. After adding RPT (rice peptide), the swelling degree of the PS-RPT complex decreased slightly, and the trend became more pronounced with increasing RPT addition.

[0046] Table 1. Expansion data of potato starch and rice peptide complexes with different contents

[0047]

[0048] Note: Different lowercase letters indicate significant differences within the same column (P<0.05). “ND” indicates that the starch granules have fully expanded.

[0049] (2) The thermodynamic properties of potato starch-rice peptide complexes in different groups were tested. The specific testing methods are as follows:

[0050] Differential scanning calorimetry (DSC) was used for determination. 3 mg of sample (dry basis) was weighed into an aluminum dish, and deionized water was added to prepare a 30% (w / w) sample emulsion. The aluminum dish was sealed and allowed to equilibrate at room temperature for 8 hours. An empty sealed aluminum dish was used as a reference. The sample was scanned within the range of 30–120 °C at a heating rate of 10 °C / min. The scanning results were analyzed using STARER software to obtain the thermodynamic characteristic parameters of the sample: initial gelatinization temperature (T0). o Peak gelatinization temperature (T) p ), final gelatinization temperature (T) c ) and enthalpy (ΔH).

[0051] The results are shown in Table 2. Compared with PS, H-RPT-0 showed increased To, Tp, and Tc, and decreased ΔH. During the preparation process, the addition of RPT delayed starch gelatinization. With increasing RPT concentration, the gelatinization temperature of PS initially increased and then decreased. When the RPT concentration increased from 0 to 10%, the gelatinization temperature of the starch continuously increased, but the gelatinization enthalpy decreased. Table 2 shows that the gelatinization temperature and enthalpy of PS do not always change in a gradient with increasing RPT concentration. When the RPT concentration was 5%–15%, the enthalpy decreased; when the concentration reached 20%, the enthalpy of the starch sample began to rise again. Therefore, the thermodynamic properties of the PS-RPT complex formed by adding different doses of RPT (5%–20%) to PS do not change according to the concentration of the added dose. This can be attributed to the fact that during the gelatinization process, RPT not only competes with starch for hydration, but may also have steric hindrance or starch-peptide interaction, which is greatly related to the concentration of RPT in the starch sample.

[0052] Table 2. Thermodynamic properties of potato starch complexes with different amounts of rice peptides

[0053] sample <![CDATA[T o (℃)]]> <![CDATA[T p (℃)]]> <![CDATA[T c (℃)]]> ΔH(J / g) PS <![CDATA[60.88±0.21 c ]]> <![CDATA[66.09±0.13 c ]]> <![CDATA[72.91±0.03 d ]]> <![CDATA[21.97±1.55 a ]]> H-RPT-0 <![CDATA[76.24±0.93 b ]]> <![CDATA[83.03±0.48 b ]]> <![CDATA[93.85±0.95 b ]]> <![CDATA[7.28±1.48 b ]]> H-RPT-5 <![CDATA[76.96±0.90 ab ]]> <![CDATA[84.06±0.24 b ]]> <![CDATA[91.18±0.40 c ]]> <![CDATA[9.09±1.95 b ]]> H-RPT-10 <![CDATA[76.36±0.90 ab ]]> <![CDATA[86.40±0.35 a ]]> <![CDATA[95.70±1.06 a ]]> <![CDATA[7.80±1.00 b ]]> H-RPT-15 <![CDATA[75.87±0.98 a ]]> <![CDATA[84.06±0.69 b ]]> <![CDATA[93.93±1.16 b ]]> <![CDATA[7.56±0.81 b <!-- 4 -->]]> H-RPT-20 <![CDATA[74.40±0.56 a ]]> <![CDATA[85.48±1.07 a ]]> <![CDATA[94.34±0.86 ab ]]> <![CDATA[8.13±0.60 b ]]>

[0054] Note: Different lowercase letters indicate significant differences within the same column (P<0.05).

[0055] (3) The gelatinization characteristics and viscosity features of the test samples were determined using a rheometer. A certain amount of sample (dry basis) was weighed into a measuring cup, and an appropriate amount of deionized water was added to prepare a 6% (w / w) sample emulsion. After thorough mixing, the emulsion was transferred into the measuring cup. The starch gelatinization mode was used for determination, with the following parameters: initial temperature 30℃, heating to 95℃ at a rate of 6℃ / min and holding for 5 min, cooling to 50℃ at a rate of 7.5℃ / min and holding for 5 min, and the viscosity versus temperature curve was recorded and saved.

[0056] The results are as follows Figure 1 As shown in Table 3, the corresponding viscosity characteristics are as follows. Table 3 shows that PS has a peak viscosity of 4300.09 cP, a disintegration value of 3171.86 cP, and a final viscosity of 1781 cP. Compared with PS, the paste viscosity of the sample prepared by the method of this invention is significantly reduced (P<0.05), including peak viscosity, valley viscosity, disintegration value, final viscosity, and recovery value.

[0057] Table 3. Viscosity characteristics of potato starch and rice peptide complexes with different contents

[0058]

[0059] Note: Different lowercase letters indicate significant differences within the same column (P<0.05).

[0060] (4) Microstructural characteristics of potato starch-rice peptide complex

[0061] 4.1 X-ray Diffraction (XRD)

[0062] Following the method of Lu et al. (2021), samples need to be equilibrated at 100% relative humidity for 24 hours before XRD diffraction. XRD diffraction parameters: monochromatic Cu-K. α X-ray diffraction (wavelength 0.1542 nm) was performed continuously for 10 seconds, with a scan start angle of 4°, an end angle of 35°, and a step size of 0.033°. After obtaining the X-ray diffraction pattern of the starch sample, the relative crystallinity of the starch sample was calculated using MDJjade 6.5 software.

[0063] 4.2 Small-angle X-ray scattering (SAXS)

[0064] A certain mass of potato starch-rice peptide complex was weighed and added to deionized water to prepare a 40% (w:w) starch emulsion. After equilibration at 4℃ for 12 h, the sample was analyzed using small-angle X-ray scattering. The starch sample was placed in a sample cell, and the test conditions were as follows: monochromatic Cu-Kα rays, wavelength 0.1542 nm, exposure time 5 min, voltage 50 kV, and current 0.6 mA. After the sample detection, the integral of the obtained two-dimensional signal was converted into a scattering vector q curve using Diffrac.SAXS software (Zhang et al., 2023).

[0065] 4.3 Fourier Transform Infrared Spectroscopy (FT-IR)

[0066] Starch samples were dried at 105℃ for 1 hour. Using the KBr pelleting method, the starch sample and KBr were thoroughly mixed, ground, and pelleted at a ratio of 1:100 (w:w). Fourier transform infrared spectroscopy was used to scan the starch samples. The test conditions were as follows: spectral range 4000–400 cm⁻¹. -1 The resolution is 4cm. -1 The infrared spectra were scanned 64 times. OMINIC software was used to perform baseline correction, normalization, and deconvolution on the obtained infrared spectra, and the full width at half maximum (FWHM) was set to 19 cm⁻¹. -1 The enhancement factor was 1.9. A length of 1042 cm was obtained. -1 1022cm -1 and 995cm -1 The intensity of the characteristic peak at that location.

[0067] X-ray diffraction patterns and relative crystallinity of potato starch complexes with different amounts of rice peptides are shown below. Figure 2 As shown. By Figure 2It is known that natural PS has a typical B-type crystalline structure. Compared with PS, the 5.5° peak of H-RPT-0 disappears in its X-ray diffraction pattern, the intensity of the peak centered at 22-24° decreases, and the broadening of the 17° peak increases. After preparation by the method of this invention, PS starch transforms from a type A crystalline structure to a type B crystalline structure. Furthermore, the diffraction peak intensity of starch slightly decreases after preparation by the method of this invention. The crystallinity of PS and H-RPT-0 are 21.5% and 19.2%, respectively. The decrease in H-RPT-0 crystallinity indicates that the preparation method of this invention disrupts the ordered structure of starch. However, as the amount of RPT added increases from 0 to 20%, the crystallinity increases from 19.2% to 22.4%. This may be related to the interaction between the RPT molecular side chains and starch molecules through electrostatic interactions. RPT promotes non-covalent interactions between starch molecular chains and between RPT and starch molecular chains, thereby forming a more compact structure and leading to increased crystallinity.

[0068] In the FT-IR spectrum of PS and the PS-RPT complex, R 1047 / R 1022 and R 1022 / R 995 The peak intensity ratios are shown in Table 4. As can be seen from Table 4, the R of PS... 1047 / 1022 and R 1022 / 995 The ratios were 0.972 and 1.006, respectively. After preparation using the method of this invention, the R... 1047 / 1022 The value increases to the range of 1.014–1.023, R 1022 / 995 The ratio decreased to the range of 0.947–0.970. This result indicates that the preparation method of the present invention improves the short-range ordered structure of starch. Furthermore, when the RPT addition amount is below 15%, R… 1047 / R 1022 As the ratio increases, R 1022 / R 995 The decrease in the ratio indicates that adding RPT during the preparation process can improve the short-range ordering of starch. However, when the RPT addition reaches 20%, R... 1047 / R 1022 and R 1022 / R 995 The peak intensity ratio did not change significantly. This is because an appropriate amount of RPT promotes non-covalent interactions between starch molecular chains and between RPT and starch molecular chains, thereby enhancing the short-range ordered structure of starch. However, when excessive RPT is added, it may affect the formation of starch crystallites.

[0069] Table 4. Short-range ordering and SAXS analysis parameters of potato starch-rice peptide complexes with different contents.

[0070] sample PS H-RPT-0 H-RPT-5 H-RPT-10 H-RPT-15 H-RPT-20 <![CDATA[R 1047 / 1022 ]]> <![CDATA[0.972±0.002 c ]]> <![CDATA[1.014±0.0003 b ]]> <![CDATA[1.017±0.0002 ab ]]> <![CDATA[1.020±0.0002 a ]]> <![CDATA[1.022±0.0004 a ]]> <![CDATA[1.019±0.0002 ab ]]> <![CDATA[R 1022 / 995 ]]> <![CDATA[1.006±0.004 a ]]> <![CDATA[0.970±0.003 b ]]> <![CDATA[0.964±0.004 b ]]> <![CDATA[0.953±0.004 c ]]> <![CDATA[0.949±0.004 c ]]> <![CDATA[0.949±0.002 c ]]> α <![CDATA[3.40±0.02 a ]]> <![CDATA[1.60±0.03 d ]]> <![CDATA[1.74±0.02 c ]]> <![CDATA[1.83±0.04 b ]]> <![CDATA[1.82±0.03 b ]]> <![CDATA[1.82±0.02 b ]]> d(nm) <![CDATA[9.59±0.00 c ]]> <![CDATA[29.96±0.10 a ]]> <![CDATA[28.78±0.18 ab ]]> <![CDATA[29.41±0.22 a ]]> <![CDATA[26.84±0.14 b ]]> <![CDATA[27.98±0.17 ab ]]> <![CDATA[D s ]]> 2.60±0.02 - - - - - <![CDATA[D m ]]> - <![CDATA[1.60±0.03 c ]]> <![CDATA[1.74±0.02 b ]]> <![CDATA[1.83±0.03 a ]]> <![CDATA[1.82±0.03 a ]]> <![CDATA[1.82±0.02 a ]]>

[0071] Note: Different lowercase letters indicate significant differences within the same column (P<0.05).

[0072] (5) In vitro digestibility of potato starch-rice peptide complex

[0073] Weigh 600 mg of sample (dry basis) into a 50 mL centrifuge tube, add 20 mL of sodium acetate buffer (0.1 mmol / L, pH 5.2), vortex thoroughly until homogeneous, and gelatinize at 100 °C for 30 min. Incubate the gelatinized sample in a 37 °C water bath. Add 5 mL of porcine trypsin (3 × 10⁻⁶ mg / mL) to each centrifuge tube containing the gelatinized sample. 3 The reaction was initiated after mixing the enzyme solution of USP and glucoamylase (40U). At 20 min and 120 min after the start of the simulated digestion experiment, 0.25 mL of the reaction solution was taken from each digestion tube and added to a centrifuge tube containing ethanol (66% v / v, 10 mL). The mixture was thoroughly mixed to stop the enzymatic digestion reaction. After centrifugation (3500 r / min, 10 min), 100 μL of the supernatant was transferred to a centrifuge tube containing 3 mL of GOPOD. The mixture was thoroughly mixed and then incubated in a water bath at 50 °C for 20 min for colorimetric reaction. The absorbance of the sample was measured at 510 nm using a UV spectrophotometer. Glucose standard was used as a standard control instead of the sample solution, and deionized water was used as a blank for zeroing. The glucose content in the reaction solution at 20 min and 120 min of digestion was calculated using the following formula:

[0074]

[0075] In the formula A t : The absorbance of the test solution; V t C: Total volume of the test solution (mL); A: Concentration of standard glucose (mg / mL); C: Total volume of the test solution (mL); C: Concentration of standard glucose (mg / mL); A ... s : Absorbance of standard glucose; W t : Sample weight (g); D: Dilution factor 40.

[0076] The contents of RDS, SDS, and RS in the sample can be calculated based on the glucose content, as shown in the following formulas:

[0077] RSD(%) = (G 20 -FG)×0.9 / TS

[0078] SDS(%) = (G 120 -G 20 )×0.9 / TS

[0079] RS(%) = [TS - (RDS + SDS)] / TS

[0080] In the formula G20 : Glucose content of starch sample at 20 min of digestion; G 120 : Glucose content of starch sample at 120 min of digestion; FG: Glucose content in sample before digestion; TS: Dry weight of starch (g).

[0081] Table 5 shows the in vitro digestibility of PS and potato starch-rice peptide complex under cooked and uncooked conditions. As shown in Table 5, under cooked conditions, the RDS content of PS was 97.78%, while the SDS and RS contents were 1.12% and 1.10%, respectively. Compared to PS, the RS content of H-RPT-0 decreased significantly. This result indicates that the preparation method of this invention significantly enhances the resistance to enzymatic hydrolysis of PS due to the increased crystallinity and short-range order, resulting in a denser structure. After adding RPT, the RDS content in samples H-RPT-5, H-RPT-10, H-RPT-15, and H-RPT-20 decreased significantly (P<0.05), while the RS and SDS contents increased significantly (P<0.05), and the trend became more pronounced with increasing RPT addition. Among them, H-RPT-20 showed the most significant decrease in digestibility (P<0.05), with the RDS content decreasing to 70.38% and the RS content increasing to 22.99%. This result indicates that the combined effect of the preparation method and RPT can effectively improve the digestibility of starch, and the digestibility becomes more pronounced with the increase of RPT addition.

[0082] Compared to cooked PS and PS-RPT complexes, the digestibility of uncooked starch samples was significantly reduced, as shown in Table 5. This is because cooking completely gelatinizes the starch, destroying its granular and crystalline structure, leading to increased digestibility. However, regardless of whether the starch was cooked or uncooked, the SDS and RS contents in the starch samples steadily increased with the increase of the RPT ratio.

[0083] Table 5. In vitro digestibility of potato starch and rice peptide complexes with different contents

[0084]

[0085] Note: Different lowercase letters indicate significant differences within the same column (P<0.05).

[0086] Example 3

[0087] The difference from Example 1 lies in the different mass percentages of wheat flour and potato starch-rice peptide complex. Specifically, the composition is: 60% wheat flour and 40% potato starch-rice peptide complex (labeled FH-40%); 70% wheat flour and 30% potato starch-rice peptide complex (labeled FH-30%); 50% wheat flour and 50% potato starch-rice peptide complex (labeled FH-50%); and 90% wheat flour and 10% potato starch-rice peptide complex (labeled FH-10%). All other components are the same as in Example 1. Different groups of crispy noodle compound powders were obtained, and each group is labeled as shown above. The group in Example 1 is labeled as FH-20%. 100% wheat flour (i.e., without potato starch-rice peptide complex, all wheat flour) is labeled FH-0%.

[0088] The following tests were conducted on different groups of dry noodle compound powders:

[0089] (1) The gelatinization characteristics and viscosity characteristics of different groups of dry crispy noodle compound powder samples were detected by rheometer, and the specific method was the same as in Example 2.

[0090] The results are as follows Figure 3 As shown in Table 6, the gelatinization curves of H-RPT-20 (representing a 2:10 mass ratio of rice peptides to potato starch in the potato starch-rice peptide complex on a dry basis) blended with wheat flour are as follows: Figure 3 As shown in Table 6, the corresponding viscosity characteristics are as follows. Table 6 shows that compared to pure wheat flour (FH-0%), the peak viscosity, valley viscosity, disintegration value, final viscosity, and retrogradation value of the compound flour significantly decreased after adding H-RPT-20 (P<0.05). With the increase of the H-RPT-20 substitution ratio, the overall viscosity of the sample gradually decreased. Peak viscosity can be used to reflect the water-holding capacity of starch during particle expansion. As the H-RPT-20 substitution ratio increased from 10% to 50%, the peak viscosity of the mixed flour decreased from 88.62 cP to 24.12 cP, indicating that the water-holding capacity of wheat flour weakened with the increase of the H-RPT-20 substitution ratio. The disintegration value decreased from 6.48 cP to 0.84 cP, indicating that H-RPT-20 can improve the high-temperature resistance and shear strength of pure wheat flour. Compared to FH-0%, the addition of H-RPT-20 significantly reduced the retrogradation value of the compound flour. The gelatinization temperature of the compound powder increased significantly with the increase of shiitake mushroom powder, indicating that the thermal stability of the mixed powder improved.

[0091] Table 6. Gelatinization characteristics of H-RPT-20 mixed with wheat flour at different ratios.

[0092]

[0093]

[0094] Note: Different lowercase letters indicate significant differences within the same column (P<0.05).

[0095] (2) Texture characteristics of different groups of dry noodle compound dough

[0096] Add 2% salt to the compound flour. Add water and knead the dough by hand for 5 minutes. After resting for 20 minutes, knead the dough a second time until the surface is smooth. Shape the prepared dough into cylindrical dough balls with a diameter of 2 cm and a height of 1.5 cm using a mold. Measure the textural properties of the dough using a texture analyzer. Specific operating mode: TPA mode, test probe P / 50, compression interval 5s. Pre-test velocity 1mm / s, in-test velocity 1mm / s, post-test velocity 5mm / s, displacement 10mm, trigger force 5g. Perform 5 parallel tests for each sample.

[0097] The effects of different replacement ratios of H-RPT-20 on the texture of wheat dough are shown in Table 7. Table 7 shows that pure wheat flour dough had the lowest hardness and chewiness, and the highest resilience, cohesion, and elasticity. When the proportion of wheat flour replaced by H-RPT-20 was 10%–50%, the hardness and chewiness of the dough increased significantly with increasing H-RPT-20 replacement ratio (P<0.05), with hardness increasing from 200.80g to 604.60g and chewiness from 106.72 to 221.33. The changes were more significant when the replacement ratio exceeded 30% (P<0.05). However, the elasticity, cohesion, and resilience of the wheat dough decreased after the addition of H-RPT-20. The adhesiveness reached its maximum value of 240.75 when the H-RPT-20 replacement ratio was 30%. When the substitution ratio exceeds 30%, the dough's adhesiveness decreases. This is likely because the increased H-RPT-20 content leads to a significant increase in the water absorption of the mixed powder, resulting in less water available for gluten formation. Therefore, when the H-RPT-20 substitution ratio does not exceed 30%, it has little impact on the dough's textural properties and is suitable for making crispy noodles.

[0098] Table 7 Effect of H-RPT-20 substitution ratio on the textural properties of wheat dough

[0099] sample Hardness / g responsive cohesion elasticity chewing Adhesion FH-0% <![CDATA[165.72±24.53 d ]]> <![CDATA[17.12±1.16 a ]]> <![CDATA[0.64±0.06 a ]]> <![CDATA[84.74±3.60 a ]]> <![CDATA[90.13±17.60 d ]]> <![CDATA[102.23±19.97 d ]]> FH-10% <![CDATA[200.80±21.89 d ]]> <![CDATA[16.97±1.17 a ]]> <![CDATA[0.63±0.06 a ]]> <![CDATA[84.15±3.79 a ]]> <![CDATA[106.72±13.83 d ]]> <![CDATA[129.05±15.78 c ]]> FH-20% <![CDATA[333.21±17.01 c ]]> <![CDATA[15.87±1.23 a ]]> <![CDATA[0.62±0.06 a ]]> <![CDATA[84.07±2.35 a ]]> <![CDATA[172.60±16.65 c ]]> <![CDATA[148.19±6.62 c ]]> FH-30% <![CDATA[475.63±14.99 b ]]> <![CDATA[16.99±0.72 a ]]> <![CDATA[0.51±0.02 b ]]> <![CDATA[82.39±2.69 a ]]> <![CDATA[198.10±10.67 ab ]]> <![CDATA[240.75±15.15 a ]]> FH-40% <![CDATA[604.60±40.37 a ]]> <![CDATA[12.75±2.70 b ]]> <![CDATA[0.45±0.12 b ]]> <![CDATA[81.93±5.42 a ]]> <![CDATA[221.33±10.51 a ]]> <![CDATA[210.26±19.96 b ]]> FH-50% <![CDATA[592.87±42.78 a ]]> <![CDATA[13.69±0.88 b ]]> <![CDATA[0.38±0.06 c ]]> <![CDATA[80.61±7.36 a ]]> <![CDATA[181.49±12.55 bc ]]> <![CDATA[205.07±15.06 b ]]>

[0100] Note: Different lowercase letters indicate significant differences within the same column (P<0.05).

[0101] Example 4

[0102] A low-GI and / or low-digestibility crispy noodle, made from the crispy noodle compound powder obtained in Example 1, is prepared by the following method:

[0103] Add 2% salt and water to the dry noodle compound powder obtained in Example 1, knead the dough by hand for 5 minutes, let it rest for 20 minutes, and then knead the dough a second time until the surface of the dough is smooth. Then place the kneaded dough in a noodle press, attach the noodle press to the main unit, and prepare the noodles into 2.0mm round noodles. Then put them in an air fryer and bake at 180℃ for 30 minutes. After natural cooling, the dry noodles are obtained.

[0104] Example 5

[0105] The difference from Example 4 is that the crispy noodle compound powders marked FH-30% and FH-10% obtained in Example 3 and marked FH-20% obtained in Example 1 were used respectively (the markings of the crispy noodles are the same as those of the compound powders), and the specific preparation method is the same as in Example 4. The crispy noodles made from 100% wheat flour (i.e., without compounded potato starch-rice peptide complex, all wheat flour) were marked as FH-0%.

[0106] Different groups of instant noodles were tested as follows:

[0107] (1) Texture characteristics of crispy noodles

[0108] Following the method of Saha et al. (2011) with appropriate modifications, the hardness and brittleness of the crispy noodles were determined using a three-point bending mode on a texture analyzer. The test conditions were as follows: probe DPH / 3PB, test speed 0.5 mm / s, initial force 10 N, return distance 30 mm, and the peak force (N) and the average distance at break (mm) were recorded.

[0109] The results are shown in Table 8. The hardness, toughness, and brittleness of FH-0% were 445.03 g, 3.56 mm, and 67.37 g·sec, respectively. Compared with crispy noodles made from pure wheat flour, the hardness, toughness, and brittleness of the crispy noodles decreased significantly when some wheat flour was replaced with H-RPT-20. However, increasing the replacement ratio from 10% to 30% had no significant effect on these properties. This may be because the addition of H-RPT-20 weakens the gluten network structure in the crispy noodles, reducing the binding force of the gluten network on the starch. Simultaneously, the relative starch content increases. During baking, the internal structure of high-starch-content noodles breaks down, leading to a loose dough and reduced hardness. Furthermore, the hydrophilic groups on RPT (rice peptide) molecules can bind water through hydrogen bonds, exhibiting good water absorption and retention properties. This increases the moisture content in the crispy noodles, making the internal structure softer and thus reducing the hardness. Therefore, the addition of H-RPT-20 can improve the textural properties of crispy noodles.

[0110] Table 8. Effect of H-RPT-20 substitution ratio on the textural properties of dry noodles

[0111] sample Hardness / g Toughness / mm Brittleness / g.sec FH-0% <![CDATA[445.03±60.79 a ]]> <![CDATA[3.56±1.29 a ]]> <![CDATA[67.37±7.63 a ]]> FH-10% <![CDATA[248.92±18.36 b ]]> <![CDATA[2.73±0.65 a ]]> <![CDATA[55.55±9.65 ab ]]> FH-20% <![CDATA[244.81±31.24 b ]]> <![CDATA[2.65±0.49 a ]]> <![CDATA[51.11±7.46 b ]]> FH-30% <![CDATA[225.35±2.08 b ]]> <![CDATA[2.62±0.23 a ]]> <![CDATA[46.77±6.15 b ]]>

[0112] Note: Different lowercase letters indicate significant differences within the same column (P<0.05).

[0113] (2) Determination of the digestibility and postprandial glycemic index of crispy noodles

[0114] 2.1 The digestibility assay method is the same as step (5) in Example 2.

[0115] Table 9 shows the in vitro digestibility data of crispy noodles prepared by mixing H-RPT-20 with wheat flour at different substitution ratios. The RDS content of crispy noodles made from pure wheat flour was 86.26%, and the SDS and RS contents were 8.32% and 5.42%, respectively. After adding H-RPT-20, the RDS content decreased from 86.26% to 41.21%, while the SDS and RS contents increased from 8.32% to 13.18% and 5.42% to 47.01%, respectively. The addition of H-RPT-20 significantly decreased the RDS content and significantly increased the RS content in the crispy noodles. With increasing H-RPT-20 addition, the SDS and RS contents in the crispy noodles increased accordingly. Therefore, compared with FH-0%, FH-10%, FH-20%, and FH-30% have higher SDS and RS content because their raw materials contain H-RPT-20 components that have undergone wet heat treatment and contain rice peptides.

[0116] Table 9. In vitro digestibility of crispy noodles prepared with different substitution ratios of H-RPT-20

[0117] sample RDS (%) SDS (%) RS (%) FH-0% <![CDATA[86.26±0.29 a ]]> <![CDATA[8.32±0.57 a ]]> <![CDATA[5.42±0.29 d ]]> FH-10% <![CDATA[74.85±1.73 b ]]> <![CDATA[13.18±2.72 b ]]> <![CDATA[11.97±2.86 c ]]> FH-20% <![CDATA[60.59±2.30 c ]]> <![CDATA[11.52±3.76 b ]]> <![CDATA[27.60±3.11 b ]]> FH-30% <![CDATA[41.21±1.16 d ]]> <![CDATA[11.78±1.35 b ]]> <![CDATA[47.01±0.93 a ]]>

[0118] Note: Different lowercase letters indicate significant differences within the same column (P<0.05).

[0119] 2.2 Postprandial glycemic index measurement

[0120] The glucose content generated in the sample at 20, 40, 60, 90, and 120 min was determined using the same method as step (5) in Example 2. A graph showing the relationship between starch hydrolysis rate and time was plotted, and a first-order kinetic fit was performed. The fitting equation is shown in equation C = C. ∞ (1-e -kt ).

[0121] Based on data obtained during in vitro hydrolysis, parameter C was determined for each starch and each formulation. ∞ The area under the hydrolysis curve (AUC) is calculated using the formula k. And the hydrolysis index (HI), see formula

[0122] In the above formula, C represents the sample hydrolysis rate at time t; C ∞ : Sample hydrolysis rate at equilibrium; k: Digestion kinetic constant.

[0123] Refer to GONI et al. ( The expected postprandial glycemic index (eGI) was calculated using the method described in 1997, as shown in the formula eGI = 39.71 + 0.549 HI.

[0124] Hydrolysis rate curves and eGI values ​​of dry noodles prepared by mixing H-RPT-20 with wheat flour at different substitution ratios are shown below. Figure 4 And as shown in Table 10. From Figure 4 It can be seen that the hydrolysis rate of all samples gradually increases and eventually stabilizes with increasing hydrolysis time. The amount of H-RPT-20 added has a significant impact on the hydrolysis rate of the crispy noodles, decreasing with increasing H-RPT-20 substitution ratio, and the time required for the hydrolysis rate to reach a constant value is shorter. When the addition amount is 0%, the starch is almost completely hydrolyzed in the first 20 minutes; when the addition amount is 10%, the time to reach a constant value is 90 minutes. When the addition amount is 20% and 30%, the time to reach a constant value is 60 minutes, and the hydrolysis rate decreases to 57.3% when the addition amount of H-RPT-20 is 20%.

[0125] Table 10 shows the indicators of crispy noodles made from pure wheat flour and those with different substitution ratios of H-RPT-20. With increasing H-RPT-20 addition, the AUG, HI, and eGI values ​​of the crispy noodles decreased, indicating that the addition of H-RPT-20 effectively reduced the eGI value of the crispy noodles. The crispy noodles made from pure wheat flour had the highest eGI at 108.09, followed by FH-10% and FH-20%, with eGIs of 100.65 and 81.14 respectively. The crispy noodle sample made from FH-30% had the lowest eGI value at 59.12, indicating significantly reduced digestibility. This is because the molecular structure of H-RPT-20 is destroyed by wet heat treatment, resulting in ordered branched clusters formed by molecular chain rearrangement. Furthermore, RPT interacts with starch molecules, promoting molecular rearrangement and aggregation, thereby improving resistance to enzymatic hydrolysis. The partial substitution of H-RPT-20 increased the RDS content in the mixed powder, thereby reducing the rate of amylase hydrolysis of the crispy noodles and slowing down the rate of glucose production after digestion in the human body. Among them, FH-30% had the slowest hydrolysis rate and the lowest eGI value. The FH-30% sample had the lowest RDS content and the highest SDS and RS content.

[0126] Table 10 H-RPT-20 Substitution Ratio for Crispy Noodles: Index Values

[0127] sample AUC HI eGI FH-0% <![CDATA[11588.58±20.25 a ]]> <![CDATA[115.89±0.20 a ]]> <![CDATA[108.09±0.17 a ]]> FH-10% <![CDATA[10725.06±256.30 b ]]> <![CDATA[107.25±2.56 b ]]> <![CDATA[100.65±2.21 b ]]> FH-20% <![CDATA[8461.64±257.17 c ]]> <![CDATA[84.62±2.57 c ]]> <![CDATA[81.14±2.22 c ]]> FH-30% <![CDATA[5907.53±54.27 d ]]> <![CDATA[59.08±0.54 d ]]> <![CDATA[59.12±0.47 d ]]>

[0128] Note: Different lowercase letters indicate significant differences within the same column (P<0.05).

[0129] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A composite powder for crisp noodles, characterized in that: The invention is composed of the following raw materials in percentage by mass: 70% to 90% of wheat flour and 10% to 30% of a potato starch-rice peptide complex; the raw materials of the potato starch-rice peptide complex include rice peptide and potato starch, and the dry basis mass ratio of the rice peptide to the potato starch is 1.5 to 2:

10.

2. The instant noodle compound powder according to claim 1, characterized in that The preparation method of the potato starch-rice peptide complex comprises the following steps: mixing rice peptide and potato starch, adding water until the moisture content of the mixture is 30% to 40%, sealing and placing at room temperature, then drying, crushing and sieving, and reacting at 95° C. to 105° C. for 17 h to 19 h to obtain the potato starch-rice peptide complex.

3. The instant noodle compound powder according to claim 2, characterized in that: The sealed storage time at room temperature is 3.5 to 4.5 hours.

4. The instant noodle compound powder according to claim 2, characterized in that: The drying temperature is 35° C. to 45° C., and the drying time is 11 h to 13 h.

5. The instant noodle compound powder according to claim 2, characterized in that: The mesh number of the sieving is 100 meshes.

6. Use of the compound powder of crisp noodles according to any one of claims 1 to 5 in the preparation of low GI and / or low digestibility foods.

7. A low GI and / or low digestibility crispy noodle, characterized in that: The instant noodle is prepared from the composite powder of any one of claims 1 to 5.

8. The method for preparing the crisp noodles according to claim 7, characterized in that: The method comprises the following steps: mixing the compound powder of the crisp noodles with water and kneading into dough, making the dough into noodles, and baking to obtain the crisp noodles.

9. The preparation method according to claim 8, characterized in that: The baking temperature is 170° C. to 190° C., and the baking time is 25 min to 35 min.

Images