Fresh and wet rice noodles with high resistant starch, preparation method of fresh and wet rice noodles and fresh and wet rice noodle product

Abstract

The preparation method of the high-resistance starch fresh and wet rice noodles comprises the following steps: uniformly mixing mixed raw materials with water according to a certain proportion for later use; s2, pouring the materials which are uniformly mixed in the step S1 into a single-screw extruder, and performing gelatinization and extrusion to form the rice noodles; standing and aging for 10 to 14 hours under the condition of 30 to 40 DEG C; performing secondary cooking and curing on the rice noodles subjected to standing and aging at the humidity of 99% and the temperature of 60-65 DEG C, wherein the steam treatment time is 4-6 hours; performing rehydration treatment on the rice noodles subjected to secondary cooking and curing; carrying out acid leaching treatment on the rehydrated rice noodles; and sub-packaging the rice noodles subjected to acid leaching treatment, and cooling after thermal sterilization. The invention relates to high-resistance starch fresh and wet rice noodles. The invention further provides a fresh and wet rice noodle product.

Description

Technical Field

[0001] The invention relates to the technical field of rice noodle processing, in particular to high-resistant starch fresh wet rice noodles and a preparation method thereof, and fresh wet rice noodle products. Background Art

[0002] As a traditional food in my country, rice noodles have a long history of more than 2,300 years. They are diverse in variety and are loved by consumers for their freshness and deliciousness. They have huge demand and have become the second largest rice product in the world. Rice noodles can usually be divided into dry rice noodles and fresh wet rice noodles according to their water content. Fresh wet rice noodles overcome the shortcomings of dry rice noodles such as poor rehydration and poor taste, and have unique advantages. However, eating fresh wet rice noodles will cause a rapid increase in blood sugar levels in the human body, and are not suitable for diabetic patients. Summary of the invention

[0003] In order to solve the technical problems existing in the above-mentioned technology, it is necessary to provide a method for preparing fresh wet rice noodles with high-resistant starch.

[0004] A method for preparing fresh wet rice noodles with high resistant starch comprises the following steps:

[0005] S1: Mix the mixed raw materials and water in a certain proportion and set aside;

[0006] S2: pouring the uniformly mixed materials in step S1 into a single screw extruder, gelatinizing and extruding to form rice noodles;

[0007] S3: Aging at 30-40℃ for 10-14h;

[0008] S4: steaming and cooking the aged rice noodles for a second time at a humidity of 99% and a temperature of 60-65° C., wherein the steam treatment time is 4-6 hours;

[0009] S5: rehydrating the twice-cooked rice noodles;

[0010] S6: performing acid leaching on the rehydrated rice noodles;

[0011] S7: Pack the rice noodles after acid immersion, sterilize them by heat and then cool them.

[0012] Preferably, in step S5, the rehydration treatment is to place the rice noodles in a water bath of 80-90° C. hot water for 7-8 minutes.

[0013] Preferably, in step S6, the acid leaching is performed by placing the rice noodles in a lactic acid bath for 2 to 3 minutes.

[0014] Preferably, in step S7, the heat sterilization is performed by placing the rice noodles in a water bath at 80 to 90°C hot water for 25 to 35 minutes.

[0015] Preferably, in step S1, the mixed raw materials include indica rice flour, milk protein and tea polyphenols.

[0016] Preferably, the mass ratio of indica rice flour, milk protein and tea polyphenols is 1:0-0.1:0-0.0002.

[0017] Preferably, the ratio of the mixed raw material to water is 5:1.

[0018] It is also necessary to provide a high-resistant starch fresh wet rice noodle.

[0019] A high-resistant starch fresh wet rice noodle is prepared by adopting the high-resistant starch fresh wet rice noodle preparation method described above.

[0020] It is also necessary to provide a kind of fresh wet rice noodle product.

[0021] A fresh wet rice noodle product comprises the above-mentioned high-resistant starch nutritious rice noodles and a seasoning adjuvant used in combination with the fresh wet rice noodles.

[0022] Compared with the prior art, the high-resistant starch fresh wet rice noodles and the preparation method and fresh wet rice noodle products provided by the present invention select indica rice flour, milk protein and tea polyphenols as raw materials for combination, screen out the ideal addition ratio, and prepare them in combination with a specific method. The texture and cooking quality of the rice noodles provided by the present invention are improved (hardness is above 1000g, chewiness is above 500g, tensile strain is above 150%, and breaking rate is below 20%). At the same time, the addition of the improver can effectively reduce the estimated GI value (eGI) of the rice noodles and reduce the sugar production capacity of the rice noodles. The addition of tea polyphenols has a more significant effect on reducing the GI value. The addition of the improver changes the rice noodles from a high glycemic index food to a medium glycemic index food. It meets the nutritional and health needs of consumers and meets the requirements of consumers for low-fat, satiety foods. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0024] Figure 1 This is a diagram showing the cooking characteristics of rice noodles with different improvers.

[0025] Figure 2 The texture characteristics of rice noodles with different improvers.

[0026] Figure 3 This is the shear curve of rice noodles with different improvers.

[0027] Figure 4 XRD patterns of rice noodles with different improvers.

[0028] Figure 5 This is a diagram showing the digestion characteristics of rice noodles with different improvers.

[0029] Figure 6 The hydrolysis curves of rice noodles with different improvers.

[0030] Figure 7 Scanning electron micrographs of rice noodles with different improvers. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Comparative Example 1:

[0033] S1: Mix indica rice flour and corn starch in a mass ratio of 10:1 in advance to form a mixed raw material, and then mix the mixed raw material with water in a ratio of 5:1 for a second time and set aside;

[0034] S2: pouring the uniformly mixed materials in step S1 into a single screw extruder, gelatinizing and extruding at 170° C. to form rice noodles;

[0035] S3: aging at 30-40°C for 10-14h; preferably at 35°C and for 12h;

[0036] S4: steaming and cooking the aged rice noodles for a second time at a humidity of 99% and a temperature of 60-65° C., wherein the steam treatment time is 4-6 hours, preferably 5 hours;

[0037] S5: placing the twice-cooked rice noodles in a water bath of 80-90° C. hot water for 7-8 minutes for rehydration treatment; the preferred temperature is 85° C.;

[0038] S6: placing the rehydrated rice noodles in a lactic acid bath for 2 to 3 minutes for acid leaching;

[0039] S7: The rice noodles after acid immersion are packaged, sterilized by heat and then cooled to obtain fresh wet rice noodles; the sample is marked as Control. Thermal sterilization is to place the rice noodles in a water bath at 80-90°C hot water for 25-35 minutes, preferably at 85°C.

[0040] Embodiment 1:

[0041] S1: Mix the mixed powder (indica rice flour and corn starch) and tea polyphenols in a mass ratio of 10:0.002 in advance to form a mixed raw material, and then mix the mixed raw material with water in a ratio of 5:1 for a second time and set aside;

[0042] S2: pouring the uniformly mixed materials in step S1 into a single screw extruder, gelatinizing and extruding at 170° C. to form rice noodles;

[0043] S3: aging at 30-40°C for 10-14h; preferably at 35°C and for 12h;

[0044] S4: steaming and cooking the aged rice noodles for a second time at a humidity of 99% and a temperature of 60-65° C., wherein the steam treatment time is 4-6 hours, preferably 5 hours;

[0045] S5: placing the twice-cooked rice noodles in a water bath of 80-90° C. hot water for 7-8 minutes for rehydration treatment; the preferred temperature is 85° C.;

[0046] S6: placing the rehydrated rice noodles in a lactic acid bath for 2 to 3 minutes for acid leaching;

[0047] S7: Pack the rice noodles after acid immersion, sterilize them by heat and then cool them to obtain fresh wet rice noodles; the sample is marked as TP0.02. Thermal sterilization is to place the rice noodles in a water bath of 80-90°C hot water for 25-35 minutes, preferably at 85°C.

[0048] Embodiment 2:

[0049] S1: Mix the mixed powder (rice flour and corn starch) and whey protein isolate in a mass ratio of 10:1 in advance to form a mixed raw material, and then mix the mixed raw material with water in a ratio of 5:1 for a second time and set aside;

[0050] S2: pouring the uniformly mixed materials in step S1 into a single screw extruder, gelatinizing and extruding at 170° C. to form rice noodles;

[0051] S3: aging at 30-40°C for 10-14h; preferably at 35°C and for 12h;

[0052] S4: steaming and cooking the aged rice noodles for a second time at a humidity of 99% and a temperature of 60-65° C., wherein the steam treatment time is 4-6 hours, preferably 5 hours;

[0053] S5: placing the twice-cooked rice noodles in a water bath of 80-90° C. hot water for 7-8 minutes for rehydration treatment; the preferred temperature is 85° C.;

[0054] S6: placing the rehydrated rice noodles in a lactic acid bath for 2 to 3 minutes for acid leaching;

[0055] S7: The rice noodles after acid immersion are packaged, and then cooled after heat sterilization to obtain fresh wet rice noodles; the sample is marked as WPI10. Heat sterilization is to place the rice noodles in a water bath of 80-90°C hot water for 25-35 minutes, preferably at 85°C.

[0056] Embodiment 3:

[0057] S1: Mix the mixed powder (indica rice flour and corn starch) and sodium caseinate in a mass ratio of 10:1 in advance to form a mixed raw material, and then mix the mixed raw material with water in a ratio of 5:1 for a second time and set aside;

[0058] S2: pouring the uniformly mixed materials in step S1 into a single screw extruder, gelatinizing and extruding at 170° C. to form rice noodles;

[0059] S3: aging at 30-40°C for 10-14h; preferably at 35°C and for 12h;

[0060] S4: steaming and cooking the aged rice noodles for a second time at a humidity of 99% and a temperature of 60-65° C., wherein the steam treatment time is 4-6 hours, preferably 5 hours;

[0061] S5: placing the twice-cooked rice noodles in a water bath of 80-90° C. hot water for 7-8 minutes for rehydration treatment; the preferred temperature is 85° C.;

[0062] S6: placing the rehydrated rice noodles in a lactic acid bath for 2 to 3 minutes for acid leaching;

[0063] S7: Pack the rice noodles after acid immersion, sterilize them by heat and then cool them to obtain fresh wet rice noodles; the sample is marked as NaCas10. Thermal sterilization is to place the rice noodles in a water bath at 80-90°C hot water for 25-35 minutes, preferably at 85°C.

[0064] Embodiment 4:

[0065] S1: Mix the mixed powder (rice flour and corn starch) with a mass ratio of 10:1:0.002, whey protein isolate and tea polyphenols in advance to form a mixed raw material, and then mix the mixed raw material with water in a ratio of 5:1 for a second time and set aside;

[0066] S2: pouring the uniformly mixed materials in step S1 into a single screw extruder, gelatinizing and extruding at 170° C. to form rice noodles;

[0067] S3: aging at 30-40°C for 10-14h; preferably at 35°C and for 12h;

[0068] S4: steaming and cooking the aged rice noodles for a second time at a humidity of 99% and a temperature of 60-65° C., wherein the steam treatment time is 4-6 hours, preferably 5 hours;

[0069] S5: placing the twice-cooked rice noodles in a water bath of 80-90° C. hot water for 7-8 minutes for rehydration treatment; the preferred temperature is 85° C.;

[0070] S6: placing the rehydrated rice noodles in a lactic acid bath for 2 to 3 minutes for acid leaching;

[0071] S7: Pack the rice noodles after acid immersion, sterilize them by heat and then cool them to obtain fresh wet rice noodles; the sample is marked as WPI10-TP0.02. Thermal sterilization is to place the rice noodles in a water bath of 80-90°C hot water for 25-35 minutes, preferably at 85°C.

[0072] Embodiment 5:

[0073] S1: Mix the mixed powder (indica rice flour and corn starch) with a mass ratio of 10:1:0.002, sodium caseinate and tea polyphenols in advance to form a mixed raw material, and then mix the mixed raw material with water in a ratio of 5:1 for a second time and set aside;

[0074] S2: pouring the uniformly mixed materials in step S1 into a single screw extruder, gelatinizing and extruding at 170° C. to form rice noodles;

[0075] S3: aging at 30-40°C for 10-14h; preferably at 35°C and for 12h;

[0076] S4: steaming and cooking the aged rice noodles for a second time at a humidity of 99% and a temperature of 60-65° C., wherein the steam treatment time is 4-6 hours, preferably 5 hours;

[0077] S5: placing the twice-cooked rice noodles in a water bath of 80-90° C. hot water for 7-8 minutes for rehydration treatment; the preferred temperature is 85° C.;

[0078] S6: placing the rehydrated rice noodles in a lactic acid bath for 2 to 3 minutes for acid leaching;

[0079] S7: Pack the rice noodles after acid immersion, sterilize them by heat and then cool them to obtain fresh wet rice noodles; the sample is labeled as NaCas10-TP0.02. Thermal sterilization is to place the rice noodles in a water bath at 80-90°C hot water for 25-35 minutes, preferably at 85°C.

[0080] In the above-mentioned embodiments 1-5, fresh wet rice noodles and a seasoning adjuvant for use with the fresh wet rice noodles can also be used in combination to obtain fresh wet rice noodle products.

[0081] The rice noodles prepared by this method were evaluated for quality and various indicators.

[0082] 1. Effects of different improvers on the cooking quality of rice noodles

[0083] Experimental methods

[0084] (1) Optimal cooking time: Measure 500 mL of tap water into a small aluminum pot (20 cm in diameter), boil it on an electric stove, randomly select 20 rice noodle samples and place them in the aluminum pot. After about 1 min of cooking, take out a rice noodle and squeeze it with a glass sheet to observe whether there is a white core. Repeat this action every 5 seconds until the white core of the rice noodle disappears. Measure 3 times.

[0085] (2) Rice noodle rehydration rate test: Weigh a certain mass of rice noodles (M1, g) with a balance and place them in an aluminum pot. Cook them for a corresponding time according to the optimal cooking time. Take out the rice noodles and soak them in cold water for 1 min. Place them on filter paper and drain for 5 min to remove the surface moisture of the rice noodles. Weigh them (mass M2, g) and calculate their rehydration rate.

[0086]

[0087] (3) Cooking loss rate: Weigh a certain mass of rice noodles (M1, g) on ​​a balance and place it in a beaker (M0, g). Cook it in an electric stove until the optimal rehydration time. After most of the water has evaporated, place the beaker in an oven and bake it to a constant weight (M3, g). Calculate the cooking loss rate.

[0088]

[0089] Where: W is the moisture content of rice noodles

[0090] (4) Breakage rate: Take 50 fresh wet rice noodles with a length of 15 cm, put them into boiling water, cook the rice noodles according to the optimal steaming time, pick up the fresh wet rice noodles that are not broken with chopsticks, and calculate the breakage rate according to the following formula. Repeat the measurement three times.

[0091]

[0092] Experimental Results

[0093] according to Figure 1The results showed that the addition of improvers can effectively reduce the cooking loss and breakage rate of rice noodles and shorten the rehydration time. This is because milk protein has excellent emulsification, stability and thickening properties, which can improve the water absorption capacity of rice noodles and accelerate the penetration of water molecules into protein and starch particles. Therefore, the rehydration time of rice noodles shows a decreasing trend, making the cooking loss rate and breakage rate show the same trend. The cooking quality of rice noodles with WPI10 added is better than that with NaCas10, and the rice noodles with tea polyphenols added are better than those with milk protein alone. Among them, the rehydration time of rice noodles with the addition of WPI10-TP0.02 improver is the shortest, and the cooking loss rate and breakage rate are the lowest.

[0094] 2. Effects of different improvers on rice noodle color

[0095] 1. Experimental method: grind the rice noodles through a grinder, pass through a 100-mesh sieve, and then measure with a colorimeter. * Represents brightness, a * represents the red and green values, b * Represents the yellow-blue value.

[0096] 2. Experimental results: As shown in Table 1, with the addition of improvers, the brightness of rice noodles decreased and the yellowness value increased, but the overall color change was acceptable. The increase in yellowness value was partly due to the color of the improver itself, and partly due to the addition of improvers causing the rice noodles to undergo Maillard reaction during high-temperature extrusion, resulting in browning, which in turn turned the rice noodles yellow.

[0097] Table 1: Chroma of rice noodles with different improvers

[0098]

[0099] Note: Different letters in the same column indicate significant differences between values ​​(P < 0.05).

[0100] 3. Effects of different improvers on the texture characteristics of rice noodles

[0101] 1. Experimental method: The texture characteristics of rehydrated rice noodles with different improvers were studied using a texture analyzer (TA). All samples were measured at the optimal cooking time, and all experiments were completed within 15 minutes after the rice noodles were rehydrated.

[0102] (1) Texture profile analysis (TPA) experimental parameter settings: probe P / 36R, pre-test speed: 2.00 mm / sec, test speed: 1.00 mm / sec, post-test speed: 1.00 mm / sec, target mode: strain: 50.00%, time: 3.00 sec, trigger force: 5.00 g. During the measurement, 6 rice noodles were placed on the stage at equal intervals, perpendicular to the test blade and parallel to the side of the stage. Repeat 3 times and take the average value. The measured indicators include hardness, viscosity, elasticity, cohesion, adhesiveness, chewiness and recovery properties (Table 2).

[0103] (2) Tensile properties: probe A / SPR, test speed: 2.00 mm / sec, post-test speed: 10.00 mm / sec, distance: 80.000 mm. Repeat the test 3 times and take the average value.

[0104] (3) Shear characteristics: The test parameters of shear characteristics are set as pre-test speed 2 mm / s, test speed 0.17 mm / s, post-test speed 2 mm / s, trigger force 15 g, and deformation degree 80%. Each time, rice noodle samples (3 to 5 strips) of uniform thickness are selected for testing, and the average value is calculated after at least 3 measurements.

[0105] Table 2: Texture parameter definition table

[0106]

[0107] 2. Experimental results: Texture is the most important quality of rice noodles. High hardness and high elasticity are both ideal quality characteristics of rice noodles. Figure 2 It can be seen that the hardness, chewiness and elasticity of rice noodles with a certain proportion of improvers are higher than those without improvers. This can be explained by the reduced rehydration time, which will allow fewer water molecules to penetrate, thereby improving the overall support, hardness and tensile strength. The hardness and chewiness of rice noodles are the greatest when the improver is WPI10-TP0.02, and the hardness of rice noodles increases from 557.59±61.78g to 1346.52±51.66g, an increase of 141.49% compared with the control group. Overall, the addition of WPI and tea polyphenols has a more obvious improvement on the texture characteristics of rice noodles.

[0108] The results of shear and tensile tests on rehydrated rice noodle samples using a texture analyzer are shown in Figure 3 As shown in Table 3. The addition of 10% NaCas did not significantly improve the quality of rice noodles, but when 10% WPI and 0.02% tea polyphenols were added, the chewing hardness of rice noodles increased from the initial 80.48±8.61g to 429.70±51.46g, and the chewing hardness of rice noodles reached the maximum. Toughness, as shown by the slope of the shear curve, was Figure 3), was used to characterize the edible quality of the samples. The illustration shows that the toughness of the rehydrated rice noodles was improved after adding the improver, among which WPI10-TP0.02 was the best additive. Under this condition, the tensile strain, chewing hardness and toughness increased from 122.76%, 80.48g and 6.30g / s to 303.67%, 429.70g and 11.82g / s, respectively, which were 147.37%, 433.92% and 87.62% higher than the control group, respectively. WPI is a protein with excellent gelling properties, which helps to increase the tensile strain of rice noodles.

[0109] Table 3: Shear and tensile properties of rice noodles with different improvers

[0110]

[0111] Note: Different letters in the same column indicate significant differences between values ​​(P < 0.05)

[0112] 4. X-ray diffraction pattern analysis of rice noodles with different improvers

[0113] Experimental method: Fresh wet rice noodles stored at 4°C for 15 days were freeze-dried for 48 hours and then ground to powder and passed through a 200-mesh sieve. Scanning speed 1 μm / min, scanning step 0.02 μm, scanning range 5-40 μm (2θ), current 40 mA, voltage 40 kV, Cu-Kα radiation (K=1.54). Relative crystallinity (RC) was calculated as follows:

[0114]

[0115] Among them A c and A a are the peak areas of the crystalline phase and the amorphous phase, respectively.

[0116] 2. Experimental results: Fresh rice noodles will produce obvious retrogradation during storage, so the crystallinity and crystal form of the rice noodles were measured. Figure 4 The characteristic peaks and relative crystallinity of rice noodles with different improvers are shown. Single-screw extruded rice noodles have a typical B-type crystal structure with three characteristic diffraction peaks at 17°, 20° and 23°. The characteristic peak at 17° is more obvious, which is caused by the recrystallization of amylopectin during the recovery process after gelatinization. The addition of improvers did not change the crystal form of rice noodles, but the relative crystallinity decreased from 32.80% to 22.57%, indicating that amylopectin was rearranged. In particular, the intensity of the 17° characteristic peak gradually decreased, indicating that the addition of improvers inhibited the long-term recovery behavior of rice starch by inhibiting the rearrangement of amylopectin. The reduction in the content of the crystalline region means the increase in the content of the amorphous region, which is conducive to the penetration of water molecules, thereby accelerating the rehydration process.

[0117] 5. Analysis of digestive characteristics and estimated GI values ​​of rice noodles with different improvers

[0118] 1. Experimental method: (1) Digestion characteristics: refer to the method of Englyst and make slight modifications. Take 0.5g of cooked rice noodles and place them in a 250ml conical flask and add 5 glass beads, add 15mL of 0.5mol / L pH=5.2 acetic acid buffer solution and 10mL of mixed enzyme solution containing saccharifying enzyme (15U / mL) and α-amylase (290U / mL). Place the conical flask in a water bath at 37℃ and shake at a speed of 130rpm to perform enzymatic hydrolysis and start timing. Accurately draw 1mL of enzymatic hydrolyzate at 0, 20, and 120min time periods, place in a centrifuge tube, add 4mL of anhydrous ethanol to inactivate, centrifuge at 4000rpm for 10min, use a glucose determination kit, and use an enzyme reader to determine the absorbance of the supernatant at 505nm, and calculate the content of fast-digestible starch, slow-digestible starch, and resistant starch according to the following formula.

[0119]

[0120] Where: G 20 :Glucose content in digestive juice at 20min (mg)

[0121] F G :Free glucose content in digestive juice (mg)

[0122] G 120 : Glucose content in digestive juice at 120 minutes (mg)

[0123] TS: Total starch content (mg)

[0124] (2) Estimated GI value:

[0125] ①Sample preparation: Same as experimental method ①

[0126] ② Oral chewing simulation: refer to the method of Gawlik-Dziki et al. and make appropriate adjustments. Take 1g of the treated sample in a conical flask, add 10mL of pH 6.5 phosphate buffer solution containing salivary amylase, tap gently with a mortar for 15s, add 5 glass beads, and shake in a 37℃ water bath for 10min.

[0127] ③ Gastric digestion simulation: adjust the pH to 1.2 with 5 M HCl, then add 10 mL of 0.03 M NaCl solution (pH = 1.2) containing pepsin, and shake in a 37°C water bath for 30 min.

[0128] ④ Intestinal digestion simulation: Use 1M NaOH to adjust the pH to 7.0, add 10mL of intestinal fluid (add 0.05g of pancreatic enzyme, 0.3g of porcine bile salt, and 0.3g of saccharifying enzyme to 100mL of phosphate buffer solution), 5mL of 120mM NaCl solution and 5mL of 120mM KCl, and shake in a 37℃ water bath for 180min. Accurately aspirate 1mL of sample at 10, 20, 30, 45, 60, 90, 120, 150, and 180min respectively, and put it into a centrifuge tube containing 4mL of anhydrous ethanol, and centrifuge at 5000rpm for 10min.

[0129] ⑤ Glucose determination: Take the supernatant after centrifugation and use a glucose determination kit to measure the absorbance at 505nm to calculate the glucose content in different time periods.

[0130] ⑥Calculation method: Calculate the hydrolysis rate of starch according to the amount of glucose released, draw a curve of the change of starch hydrolysis rate over time, and calculate the digestion curve of all rice noodle samples according to equation C t =C ∞ (1-e -kt ) was used for first-order kinetic fitting, and origin software was used for model fitting and mapping, and the hydrolysis equilibrium constant k was calculated.

[0131] The area under the digestion curve (AUC) was calculated by the following formula:

[0132]

[0133] Where: C t : Starch hydrolysis rate at time t; C ∞ : Final starch hydrolysis rate; t f : total digestion reaction time (180 min); t0: digestion start time (0 min); k: kinetic constant

[0134] The hydrolysis index (HI) is calculated by the following formula:

[0135]

[0136] Choose white bread as a reference and calculate the GI of rice noodles using the following formula:

[0137] GI=0.862HI+8.198

[0138] Glycemic load (GL) is the product of a food's GI and total carbohydrate intake.

[0139] 2. Experimental results: From the digestion characteristics diagram ( Figure 5) It can be seen that compared with the control rice noodles, the addition of the improver gradually reduced the content of fast-digestible starch in the rice noodles, while the content of slowly digestible starch and resistant starch increased accordingly. The RDS content of the rice noodles decreased from the initial 63.34% to 55.19%, the SDS content increased from the initial 20.22% to 22.43%, and the RS content increased from the initial 16.44% to 22.48%. The increase in RS content was greater than that of SDS, which may be due to the fact that polyphenols are mainly involved in the formation of starch single helices.

[0140] From the hydrolysis curve ( Figure 6 ) and Table 4 show that the addition of improvers can effectively reduce the estimated GI value (eGI) of rice noodles and reduce the sugar production capacity of rice noodles, and the addition of tea polyphenols has a more significant effect in reducing the GI value.

[0141] Due to the reduction of total starch content, the available carbohydrate content in rice noodles is reduced and the protein content is increased, resulting in a decrease in fast-digestible starch and glycemic index. In addition, studies have shown that exogenously added protein can form a physical barrier or interact with starch through non-covalent bonds (such as hydrogen bonds and hydrophobic interactions) and covalent bonds, inhibiting amylase activity and effectively reducing the digestibility of starch.

[0142] Table 4: Rice noodle digestion model parameters, estimated glycemic index and glycemic load

[0143]

[0144] Note: Different letters in the same column indicate significant differences between values ​​(P < 0.05).

[0145] 6. SEM analysis of rice noodles with different improvers

[0146] 1. Experimental method: Drain the surface moisture of rice noodles cooked for the best cooking time, freeze them at -80℃ for 8-10 hours, and then freeze-dry them in a freeze dryer for 72 hours. Observe the network structure of rice noodles by scanning electron microscope. The test voltage is 8kV and the current is 8μA.

[0147] 2. Experimental results: Figure 7 It can be seen from the scanning electron microscope image that the addition of WPI10-TP0.02 improver significantly changed the internal morphology of the rice noodles. The network structure inside the rice noodles became denser, the pores became smaller, and it had a more compact and dense network structure, which increased the gel strength inside the rice noodles.

[0148] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0149] What is disclosed above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for preparing fresh wet rice noodles with high resistant starch, characterized in that: The following steps are included: S1: Mix the mixed raw materials and water in a certain proportion and set aside; S2: pouring the uniformly mixed materials in step S1 into a single screw extruder, gelatinizing and extruding to form rice noodles; S3: Aging at 30-40℃ for 10-14h; S4: steaming and cooking the aged rice noodles for a second time at a humidity of 99% and a temperature of 60-65° C., wherein the steam treatment time is 4-6 hours; S5: rehydrating the twice-cooked rice noodles; S6: performing acid leaching on the rehydrated rice noodles; S7: Pack the rice noodles after acid immersion, sterilize them by heat and then cool them.

2. The method for preparing fresh wet rice noodles with high resistant starch according to claim 1, characterized in that: In step S5, the rehydration treatment is to place the rice noodles in a water bath of 80-90° C. hot water for 7-8 minutes.

3. The method for preparing fresh wet rice noodles with high resistance starch according to claim 1, characterized in that: In step S6, the acid leaching is to place the rice noodles in a lactic acid bath for 2 to 3 minutes.

4. The method for preparing fresh wet rice noodles with high resistance starch according to claim 1, characterized in that: In step S7, thermal sterilization is performed by placing the rice noodles in a water bath at 80 to 90°C hot water for 25 to 35 minutes.

5. The method for preparing fresh wet rice noodles with high resistance starch according to claim 1, characterized in that: In step S1, the mixed raw materials include indica rice flour, milk protein, and tea polyphenols.

6. The method for preparing fresh wet rice noodles with high resistance starch according to claim 5, characterized in that: The mass ratio of indica rice flour, milk protein and tea polyphenols is 1:0~0.1:0~0.0002.

7. The method for preparing fresh wet rice noodles with high resistance starch according to claim 1, characterized in that: The ratio of mixed raw materials to water is 5:

1.

8. A high-resistant starch fresh wet rice noodle, characterized by: The high-resistant starch fresh wet rice noodles are prepared by the preparation method of high-resistant starch fresh wet rice noodles according to any one of claims 1 to 7.

9. A fresh wet rice noodle product, characterized in that: The invention comprises the fresh wet rice noodles with high resistance starch as claimed in claim 8, and a seasoning adjuvant used in combination with the fresh wet rice noodles.

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