Preparation method for improving quality of rice noodles based on acetate starch

Abstract

The invention discloses a preparation method for improving the quality of rice noodles based on acetate starch, which comprises the following steps: A, extracting starch, and carrying out acetate modification treatment on the obtained starch; b, mixing rice starch with distilled water to obtain a starch suspension, adding boiling water into the obtained suspension, and stirring to obtain a starchy sauce paste; c, compounding the acetate starch obtained in the step A with rice starch, and uniformly mixing; d, kneading the cooked gordon euryale seed obtained in the step B and the compound starch obtained in the step C into smooth dough, covering the dough with a preservative film, and standing; e, extruding the dough obtained in the step D into rice noodles by using a noodle press, and cooking the obtained rice noodles in boiling water; and F, after fishing out, cooling in cold water, fishing out, wiping water on the surface, and freezing in a refrigerator. Compared with a traditional method for preparing the rice noodles, the method has the advantages that alum is not used, the quality deterioration of the fresh and wet rice noodles caused by freezing is improved by utilizing specific acetate starch, and the prepared rice noodles have good toughness, ductility, boiling fastness and cooking characteristics.

Description

Technical Field

[0001] The invention belongs to the technical field of fresh wet rice noodle processing, relates to a preparation method for improving the quality of rice noodles based on acetate starch, and in particular to a preparation method for alum-free frozen fresh wet rice noodles based on acetate starch. Background Art

[0002] Fresh wet rice noodles, a traditional staple food in southern China, have a rich culinary culture thanks to their unique processing characteristics and diverse cooking methods (boiling, stir-frying, deep-frying, and cold dressing). However, in industrialized production, persistent technical bottlenecks such as high breakage rates, high cooking losses, and low cooking yields have become key obstacles hindering industrial upgrading. To improve product texture, traditional processes commonly use the aluminum-containing additive alum (primarily potassium aluminum sulfate). However, studies have shown that its potential health risks cannot be ignored: aluminum ions are neurotoxic and can competitively inhibit intestinal absorption of essential minerals such as iron and calcium. Long-term intake may lead to decreased bone density and iron-deficiency anemia. Epidemiological studies have also suggested a positive correlation between alum and the incidence of Alzheimer's disease. Therefore, developing safe, economical, and functional alum alternatives has become an important research direction in rice noodle processing.

[0003] Current research on alternative technologies mainly focuses on three systems: hydrophilic colloids (konjac gum, locust bean gum, guar gum), proteins (egg white protein, wheat gluten protein) and inorganic salt compound systems. It is worth noting that although hydrophilic colloids such as konjac gum can effectively improve the tensile strength of fresh wet rice noodles, the cost of its raw materials is significantly higher than that of traditional processes; although wheat gluten protein can improve the gel network structure, it significantly affects the transparency of the final product; and although inorganic salts such as phosphates have controllable costs, they are not effective in reducing key indicators such as cooking loss rate, and it is still difficult to achieve the multi-dimensional quality improvement effect unique to alum. This efficacy-cost binary paradox poses a severe challenge to the development of new alternative formulas.

[0004] Furthermore, some fresh wet rice noodles are currently produced using a freezing process to maintain a high moisture content. This freezing process can lead to structural damage from ice crystals, freeze-thaw cycle degradation, moisture migration and frosting, and starch retrogradation. These factors collectively lead to increased breakage, deterioration in cooking properties, and decreased toughness, significantly impacting product quality stability and consumer experience. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a preparation method for improving the quality of rice noodles based on acetate starch, in particular, a preparation method for alum-free frozen fresh wet rice noodles based on acetate starch that still maintains good toughness, ductility, and cooking characteristics after freezing. In order to improve the quality of fresh wet rice noodles and reduce the quality deterioration caused by freezing, the present invention uses acetate starch as an auxiliary material to improve the quality of fresh wet rice noodles. It has the characteristics of significantly improving the quality of fresh wet rice noodles after freezing, and has significant advantages in actual production. Acetate starch can significantly improve the boiling resistance, transparency and ductility of fresh wet rice noodles, reduce the breakage rate, and avoid the problems of traditional fresh wet rice noodles that are easy to become mushy and sticky. In addition, acetate starch can replace alum (aluminum-containing additives) in traditional processes, completely avoiding the risk of aluminum residues, and meeting the needs of modern consumers for healthy food. In summary, acetate starch not only improves the quality and safety of fresh wet rice noodles, but also promotes the upgrading of production processes towards high efficiency and environmental protection, which is in line with the trend of health and sustainable development of the food industry.

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

[0007] The present invention provides a method for preparing alum-free frozen fresh wet rice noodles based on starch acetate, the method comprising the following steps:

[0008] A. Preparation of starch acetate: Acetylation of cereal starch;

[0009] B. Preparation of glutinous rice paste: rice starch is added to water to prepare a starch suspension, boiling water is added to the suspension, and stirring is performed to prepare glutinous rice paste;

[0010] C. Preparation of compound starch: Compounding and mixing the acetate starch obtained in step A with rice starch;

[0011] D. Preparation of dough: Knead the cooked starch obtained in step B and the compound starch obtained in step C into a smooth dough and let it stand;

[0012] E. Preparation of fresh wet rice noodles: Extrude the dough obtained in step D into rice noodles, and then remove them after steaming;

[0013] F. Cooling and freezing: Cool the fresh wet rice noodles obtained in step E in cold water, remove them from the rice noodles, drain them / wipe off the surface moisture, and then freeze them.

[0014] As an embodiment, the cereal starch is buckwheat starch, oat starch or a combination of two thereof.

[0015] In one embodiment, the grain starch is prepared by soaking grains in an alkaline solution overnight, washing to remove the alkaline solution, crushing and sieving, centrifuging to remove the supernatant and protein layer, and repeatedly washing with water until the starch suspension is neutral and free of protein residue; suspending the starch in ethanol, filtering, drying, and grinding and sieving. The resulting starch has a particle size of less than 10 μm, similar to that of rice starch.

[0016] As an embodiment, it also includes at least one of the following technical features:

[0017] S1, the alkali solution is 3-4g / L sodium hydroxide solution;

[0018] S2, crushed through 100-200 mesh sieve;

[0019] S3, filter and dry for 48 to 60 hours;

[0020] S4. After grinding, pass through 80-100 mesh sieve.

[0021] In one embodiment, the modifying agent used in the acetylation treatment is acetic anhydride, and the amount used is 3-5% by weight of the dry weight of the cereal starch. The acetyl content of the resulting acetate starch is less than 2.5%, which complies with the acetyl content of acetate starch specified in GB 29925-2013.

[0022] As an embodiment, the acetylation treatment comprises:

[0023] A1. Mix corn starch with deionized water to prepare a 40% starch emulsion. Adjust the pH of the system to 8.2-8.4 with 3% sodium hydroxide and stir for 10-20 minutes.

[0024] A2. Add acetic anhydride dropwise and react for 45 min-1 h. During the reaction, use (3%) sodium hydroxide to adjust the pH of the system to 8.0-8.4. After the reaction, use (0.5 mol / L) hydrochloric acid to adjust the pH to 6.5±0.1. Filter, wash, and dry to obtain acetate starch.

[0025] As an embodiment, in step A2, the drying temperature is 35-38° C., and the drying time is 40-56 h.

[0026] As an embodiment, in step B, the water temperature for preparing the starch suspension is 40-45° C., and the mass ratio of rice starch to water is 1:1-1:5; it can be 1:1-1:3, 1:3-1:5, etc.

[0027] As an embodiment, in step C, the amount of starch acetate added is 1% to 5% of the mass of rice starch.

[0028] As an embodiment, in step D, the mass ratio of cooked starch to compound starch is 4:5 to 6:5.

[0029] As an embodiment, in step D, the standing time is 3 to 5 minutes.

[0030] As an embodiment, in step E, the cooking time is 5 to 10 seconds.

[0031] As an embodiment, the cooling temperature in step F is 20-25° C., and the cooling time is 45-60 min.

[0032] As an embodiment, the freezing temperature in step F is -12 to -18°C, and the freezing time is 36 to 48 hours.

[0033] The starch acetate starch used in the present invention is oat starch and buckwheat starch. The particle size of these two starches is less than 10 μm, which is similar to that of rice starch. Therefore, the compounded starch can maintain a similar water absorption rate and expansion volume during the gelatinization process. The presence of acetyl groups further promotes the opening and dispersion of starch molecular chains. After gelatinization, the compounded starch with a similar expansion volume forms a uniform amorphous region with acetyl groups evenly distributed therein. During the cooling and regeneration process, the evenly dispersed starch molecular chains entangle with each other and are more likely to form a uniform and compact gel network structure. During the freezing process, the compact gel network structure in the fresh wet rice noodles slows down the formation and growth of ice crystals, thereby inhibiting the mechanical damage of ice crystals to the microstructure of the fresh wet rice noodles. This effect helps maintain the toughness of the fresh wet rice noodles and delays the hardening trend during frozen storage, thereby enhancing the toughness and ductility of the frozen fresh wet rice noodles, improving the tensile strength and stretching distance of the fresh wet rice noodles, and reducing the breakage rate of the fresh wet rice noodles. Furthermore, the uniform distribution of acetyl groups in frozen fresh wet rice noodles minimizes interactions between starch molecular chains, inhibiting further dehydration of the gel network structure in the thawed fresh wet rice noodles. This allows the thawed fresh wet rice noodles to retain a high moisture content and a compact gel network structure. This enhances the water retention capacity of the thawed fresh wet rice noodles during the cooking process, reduces the leaching of amylose, and thus increases the cooking yield of the fresh wet rice noodles and reduces their cooking loss rate. Therefore, the present invention can enhance the toughness, ductility, and cooking resistance of the frozen fresh wet rice noodles, reduce breakage, and thus improve the overall quality of the fresh wet rice noodles, making them smoother and more satisfying to consumers.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] (1) The present invention uses acetate oat / buckwheat starch as an additive, which can reduce product aging and quality deterioration caused by freezing, and effectively improve the toughness, ductility, boiling resistance, and cooking properties of fresh wet rice noodles after freezing, making fresh wet rice noodles more suitable for modern food processing needs, especially in the application scenarios of fast food, freezing and high-temperature cooking. It has obvious advantages.

[0036] (2) The method of the present invention has simple steps, is easy to implement, has high production efficiency and low operating cost. DETAILED DESCRIPTION

[0037] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0038] The following are the methods for measuring the starch particle size, tensile strength, cooking properties, and breaking rate of the examples and comparative examples, specifically:

[0039] Add an appropriate amount of starch to deionized water and vortex to mix well to prepare a 0.1% starch suspension. The refractive index of deionized water is set to 1.33, and the refractive index of the starch sample is set to 1.50. The particle size of the starch sample is measured using a laser particle size analyzer.

[0040] Adjust the texture analyzer to tensile mode. Use the A / SPR fixture. The parameters of the texture analyzer operating program are set as follows: the probe travel speed before, during, and after the test is 3mm / s, the stretching distance is 100mm, the trigger force is 5.0g (automatic mode), and the data collection frequency is 200pps. Before the test, take the fresh wet rice noodles out of the refrigerator and thaw them at room temperature. Steam the thawed rice noodles in boiling water for 5 minutes, remove them and wipe off excess water on the surface, seal them with plastic wrap, let them stand for 10 minutes, and wrap the two ends of the rice noodles around the A / SPR fixture for tensile measurement. Repeat each sample at least 10 times, select five groups of samples with larger tensile force, and record their maximum tensile force and the tensile distance (mm) when they break. The tensile strength calculation formula is as follows:

[0041] Tensile strength (g / mm 2 ) = maximum tensile strength (g) / cross-sectional area of ​​fresh wet rice noodles (mm 2 )

[0042] Compared to TPA, tensile texture more closely reflects the stress response of rice noodles during consumption, more accurately reflecting key quality indicators such as tensile strength, fracture distance, and toughness. It is particularly suitable for evaluating the chewing experience of rice noodles, such as their chewiness and durability. In contrast, TPA, which primarily simulates compression, struggles to fully capture the true textural characteristics of rice noodles during stretching and fracture. Therefore, the present invention uses tensile texture to evaluate the textural properties of rice noodles.

[0043] Weigh a certain weight (W1) of thawed fresh wet rice noodles (water content W), soak them in distilled water for 5 minutes, dry the surface moisture, and cook them in boiling water for 5 minutes. Then, cool the cooked rice noodles in distilled water, wipe off the excess surface moisture, and weigh them (W2). The weighed rice noodles are dried at 110°C to a constant weight, removed, cooled to room temperature in a drying dish, and weighed (W3). The cooking yield (CY) and cooking loss (CL) of rice noodles are calculated as follows:

[0044] CY(%)=W2 / W1×100

[0045] CL(%)=(W1-W3) / [W1ⅹ(1-W)]ⅹ100

[0046] Randomly select 100 fresh wet rice noodles without mechanical damage after thawing, place them in boiling water and cook for 25 minutes, and record the total number of rice noodles after cooking.

[0047] Broken strip rate = (total number - 100) / 100 x 100

[0048] Example 1

[0049] This embodiment relates to a method for improving the quality of fresh wet rice noodles under freezing conditions based on acetate buckwheat starch, and the steps are as follows:

[0050] Step 1: Soak 200g of buckwheat seeds in 1L of sodium hydroxide solution (4g / L) overnight, wash to remove the alkali solution, grind and crush, and pass through a 200-mesh sieve. Centrifuge to remove the supernatant and protein layer, and repeatedly wash with water until the starch suspension is neutral and no protein remains. Finally, suspend the starch in ethanol, filter, dry at 37°C for 48 hours, grind, and pass through a 100-mesh sieve to produce buckwheat starch.

[0051] Step 2: The buckwheat starch obtained in step 1 is mixed with deionized water to prepare a 40% starch milk, the pH of the system is adjusted to 8.4 using 3% sodium hydroxide, the mixture is stirred for 15 minutes, acetic anhydride (5% by weight of the dry weight of the starch) is added dropwise, and the reaction is carried out for 1 hour. During the reaction, the pH of the system is adjusted to 8.0-8.4 using 3% sodium hydroxide. After the reaction, the pH is adjusted to 6.5 using 0.5 mol / L hydrochloric acid, the mixture is filtered and washed, and dried in an oven at 37°C for 48 hours to obtain acetate buckwheat starch.

[0052] Step 3: Evenly mix the acetate starch obtained in step 2 with 75 g of rice starch, wherein the amount of acetate starch added is 1% of the mass of the rice starch.

[0053] Step 4: Weigh 15 g of rice starch and add 15 g of deionized water (water temperature is 40° C.) to prepare a starch suspension, add 45 g of boiling water, and stir to prepare a glutinous rice starch.

[0054] Step 5: Knead the starch obtained in step 4 and the starch obtained in step 3 into a smooth dough (wherein the mass ratio of cooked starch to compound starch is 1:1), cover with plastic wrap, and let stand at room temperature for 5 minutes.

[0055] Step 6: Use a noodle press to squeeze the dough obtained in step 5 into rice noodles with a diameter of 3 mm. Steam the obtained rice noodles in boiling water for 5 seconds, then remove them, cool them in cold water for 1 hour, remove them, wipe off the surface moisture, and freeze them in a refrigerator at -18°C for 48 hours.

[0056] Step 7: Determine the cooking characteristics, tensile strength, tensile distance when breaking, and breakage rate of the thawed fresh wet rice noodles.

[0057] Implementation effect: The median particle size of buckwheat starch was measured to be 4.48μm, and the median particle size of rice starch was 5.79μm. The particle sizes of the two starches were similar, both less than 10μm, and they both belong to small-particle starch.

[0058] The tensile strength of the rice flour prepared in this embodiment is 15.44 g / mm 2 The tensile distance when breaking occurred was 27.86 mm, the cooking yield was 207.4%, the cooking loss rate was 13.3%, and the broken strip rate was 8.8%.

[0059] Example 2

[0060] This embodiment relates to a method for improving the quality of fresh wet rice noodles under freezing conditions based on acetate buckwheat starch, and the steps are as follows:

[0061] Step 1: Soak 200g of buckwheat seeds in 1L of sodium hydroxide solution (4g / L) overnight, wash to remove the alkali solution, grind and crush, and pass through a 200-mesh sieve. Centrifuge to remove the supernatant and protein layer, and repeatedly wash with water until the starch suspension is neutral and no protein remains. Finally, suspend the starch in ethanol, filter, dry at 37°C for 48 hours, grind, and pass through a 100-mesh sieve to produce buckwheat starch.

[0062] Step 2: The oat starch obtained in step 1 is mixed with deionized water to prepare a 40% starch milk, the pH of the system is adjusted to 8.4 using 3% sodium hydroxide, the mixture is stirred for 15 minutes, acetic anhydride (5% by weight of the dry weight of the starch) is added dropwise, and the mixture is reacted for one hour. During the reaction, the pH of the system is adjusted to 8.0-8.4 using 3% sodium hydroxide. After the reaction, the pH is adjusted to 6.5 using 0.5 mol / L hydrochloric acid. The mixture is filtered and washed, and dried in an oven at 37°C for 48 hours to obtain acetate buckwheat starch.

[0063] Step 3: Evenly mix the acetate starch obtained in step 2 with 75 g of rice starch, wherein the amount of acetate starch added is 3% of the mass of the rice starch.

[0064] Step 4: Weigh 15 g of rice starch and add 15 g of deionized water (water temperature is 40° C.) to prepare a starch suspension, add 45 g of boiling water, and stir to prepare a glutinous rice starch.

[0065] Step 5: Knead the starch obtained in step 4 and the starch obtained in step 3 into a smooth dough (wherein the mass ratio of cooked starch to compound starch is 1:1), cover with plastic wrap, and let stand at room temperature for 5 minutes.

[0066] Step 6: Use a noodle press to squeeze the dough obtained in step 5 into rice noodles with a diameter of 3 mm. Steam the obtained rice noodles in boiling water for 5 seconds, then remove them, cool them in cold water for 1 hour, remove them, wipe off the surface moisture, and freeze them in a refrigerator at -18°C for 48 hours.

[0067] Step 7: Determine the cooking characteristics, tensile strength, tensile distance when breaking, and breakage rate of the thawed rice noodles.

[0068] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 16.30g / mm 2 The tensile distance when breaking occurred was 26.37 mm, the cooking yield was 198.2%, the cooking loss rate was 11.0%, and the broken strip rate was 3.8%.

[0069] Example 3

[0070] This embodiment relates to a method for improving the quality of fresh wet rice noodles under freezing conditions based on acetate buckwheat starch, and the steps are as follows:

[0071] Step 1: Soak 200g of buckwheat seeds in 1L of sodium hydroxide solution (4g / L) overnight, wash to remove the alkali solution, grind and crush, and pass through a 200-mesh sieve. Centrifuge to remove the supernatant and protein layer, and repeatedly wash with water until the starch suspension is neutral and no protein remains. Finally, suspend the starch in ethanol, filter, dry at 37°C for 48 hours, grind, and pass through a 100-mesh sieve to produce buckwheat starch.

[0072] Step 2: The buckwheat starch obtained in step 1 is mixed with deionized water to prepare a 40% starch milk, the pH of the system is adjusted to 8.4 using 3% sodium hydroxide, the mixture is stirred for 15 minutes, acetic anhydride (5% by weight of the dry weight of the starch) is added dropwise, and the mixture is reacted for one hour. During the reaction, the pH of the system is adjusted to 8.0-8.4 using 3% sodium hydroxide. After the reaction, the pH is adjusted to 6.5 using 0.5 mol / L hydrochloric acid. The mixture is filtered and washed, and dried in an oven at 37°C for 48 hours to obtain acetate buckwheat starch.

[0073] Step 3: Evenly mix the acetate starch obtained in step 2 with 75 g of rice starch, wherein the amount of acetate starch added is 5% of the mass of the rice starch.

[0074] Step 4: Weigh 15 g of rice starch and add 15 g of deionized water (water temperature is 40° C.) to prepare a starch suspension, add 45 g of boiling water, and stir to prepare a glutinous rice starch.

[0075] Step 5: Knead the starch obtained in step 4 and the starch obtained in step 3 into a smooth dough (wherein the mass ratio of cooked starch to compound starch is 1:1), cover with plastic wrap, and let stand at room temperature for 5 minutes.

[0076] Step 6: Use a noodle press to squeeze the dough obtained in step 5 into rice noodles with a diameter of 3 mm. Steam the obtained rice noodles in boiling water for 5 seconds, then remove them, cool them in cold water for 1 hour, remove them, wipe off the surface moisture, and freeze them in a refrigerator at -18°C for 48 hours.

[0077] Step 7: Determine the cooking characteristics, tensile strength, tensile distance when breaking, and breakage rate of the thawed rice noodles.

[0078] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 15.97 g / mm 2 The tensile distance when breaking occurred was 27.54 mm, the cooking yield was 202.5%, the cooking loss rate was 12.0%, and the broken strip rate was 7.5%.

[0079] Example 4

[0080] This embodiment relates to a method for improving the quality of fresh wet rice noodles under freezing conditions based on acetate oat starch. The method is the same as that in Example 1, except that the starch in step 1 is replaced with oat starch.

[0081] Implementation effect: The median particle size of oat starch was measured to be 7.71μm, and the median particle size of rice starch was 5.79μm. The particle sizes of the two starches were similar, both less than 10μm, and they both belong to small-particle starch.

[0082] The tensile strength of the fresh wet rice noodles prepared in this embodiment is 14.37 g / mm 2The tensile distance when breaking occurred was 25.40 mm, the cooking yield was 210.0%, the cooking loss rate was 7.90%, and the broken strip rate was 10.0%.

[0083] Example 5

[0084] This embodiment relates to a method for improving the quality of fresh wet rice noodles under freezing conditions based on acetate oat starch. The method is the same as that in Example 2, except that the starch in step 1 is replaced with oat starch.

[0085] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 17.39g / mm 2 The tensile distance when breaking occurred was 24.81 mm, the cooking yield was 191.5%, the cooking loss rate was 8.90%, and the broken strip rate was 1.3%.

[0086] Example 6

[0087] This embodiment relates to a method for improving the quality of fresh wet rice noodles under freezing conditions based on acetate oat starch. The method is the same as that in Example 3, except that the starch in step 1 is replaced with oat starch.

[0088] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 14.48g / mm 2 The tensile distance when breaking occurred was 27.34 mm, the cooking yield was 195.4%, the cooking loss rate was 9.40%, and the broken strip rate was 6.3%.

[0089] Example 7

[0090] This embodiment relates to a method for improving the quality of fresh wet rice noodles under freezing conditions based on acetate buckwheat starch. The method is the same as that in Example 1, except that the freezing time in step 6 is changed to 120 hours.

[0091] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 13.56g / mm 2 The tensile distance when breaking occurred was 24.16 mm, the cooking yield was 192.6%, the cooking loss rate was 14.1%, and the broken strip rate was 13.5%.

[0092] Example 8

[0093] This embodiment relates to a method for improving the quality of fresh wet rice noodles under freezing conditions based on acetate buckwheat starch. The method is the same as that in Example 2, except that the freezing time in step 6 is changed to 120 hours.

[0094] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 15.17g / mm 2The tensile distance when breaking occurred was 25.39 mm, the cooking yield was 193.9%, the cooking loss rate was 14.0%, and the broken strip rate was 10.8%.

[0095] Example 9

[0096] This embodiment relates to a method for improving the quality of fresh wet rice noodles under freezing conditions based on acetate buckwheat starch. The method is the same as that in Example 3, except that the freezing time in step 6 is changed to 120 hours.

[0097] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 14.37g / mm 2 The tensile distance when breaking occurred was 24.74 mm, the cooking yield was 190.5%, the cooking loss rate was 16.0%, and the broken strip rate was 10.5%.

[0098] Example 10

[0099] This embodiment relates to a method for improving the quality of fresh wet rice noodles under freezing conditions based on acetate oat starch. The method is the same as that in Example 4, except that the freezing time in step 6 is changed to 120 hours.

[0100] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 13.77g / mm 2 The tensile distance when breaking occurred was 23.44 mm, the cooking yield was 191.7.0%, the cooking loss rate was 9.90%, and the broken strip rate was 14.0%.

[0101] Example 11

[0102] This embodiment relates to a method for improving the quality of fresh wet rice noodles under freezing conditions based on acetate oat starch. The method is the same as that in Example 5, except that the freezing time in step 6 is changed to 120 hours.

[0103] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 11.79g / mm 2 The tensile distance when breaking occurred was 21.97 mm, the cooking yield was 189.8%, the cooking loss rate was 10.40%, and the broken strip rate was 12.3%.

[0104] Example 12

[0105] This embodiment relates to a method for improving the quality of fresh wet rice noodles under freezing conditions based on acetate oat starch. The method is the same as that in Example 6, except that the freezing time in step 6 is changed to 120 hours.

[0106] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 12.89g / mm 2The tensile distance when breaking occurred was 22.19 mm, the cooking yield was 191.1%, the cooking loss rate was 9.97%, and the broken strip rate was 11.7%.

[0107] Example 13

[0108] This embodiment relates to a method for improving the quality of fresh wet rice noodles under room temperature conditions based on acetate buckwheat starch. The method is the same as that in Example 1, except that the frozen storage for 48 hours in step 6 is replaced with room temperature storage for 48 hours.

[0109] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 12.77g / mm 2 The tensile distance when breaking occurred was 20.16 mm, the cooking yield was 191.4%, the cooking loss rate was 15.7%, and the broken strip rate was 16.8%.

[0110] Example 14

[0111] This embodiment relates to a method for improving the quality of fresh wet rice noodles under room temperature conditions based on acetate buckwheat starch. The method is the same as that in Example 2, except that the frozen storage for 48 hours in step 6 is replaced with room temperature storage for 48 hours.

[0112] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 12.51g / mm 2 The tensile distance when breaking occurred was 20.47 mm, the cooking yield was 189.2%, the cooking loss rate was 15.0%, and the broken strip rate was 16.0%.

[0113] Example 15

[0114] This embodiment relates to a method for improving the quality of fresh wet rice noodles under room temperature conditions based on acetate buckwheat starch. The method is the same as that in Example 3, except that the frozen storage for 48 hours in step 6 is replaced with room temperature storage for 48 hours.

[0115] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 13.17g / mm 2 The tensile distance when breaking occurred was 21.44 mm, the cooking yield was 192.5%, the cooking loss rate was 12.0%, and the broken strip rate was 15.5%.

[0116] Example 16

[0117] This embodiment relates to a method for improving the quality of fresh wet rice noodles under room temperature conditions based on acetate oat starch. The method is the same as that in Example 4, except that the frozen storage for 48 hours in step 6 is replaced with room temperature storage for 48 hours.

[0118] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 12.19g / mm 2 The tensile distance when breaking occurred was 21.06 mm, the cooking yield was 193.4%, the cooking loss rate was 12.7%, and the broken strip rate was 13.8%.

[0119] Example 17

[0120] This embodiment relates to a method for improving the quality of fresh wet rice noodles under room temperature conditions based on acetate oat starch. The method is the same as that in Example 5, except that the frozen storage for 48 hours in step 6 is changed to room temperature storage for 48 hours.

[0121] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 12.37g / mm 2 The tensile distance when breaking occurred was 20.97 mm, the cooking yield was 191.2%, the cooking loss rate was 13.5%, and the broken strip rate was 15.5%.

[0122] Example 18

[0123] This embodiment relates to a method for improving the quality of fresh wet rice noodles under room temperature conditions based on acetate oat starch. The method is the same as Example 6, except that the frozen storage for 48 hours in step 6 is changed to room temperature storage for 48 hours.

[0124] Implementation effect: The tensile strength of the fresh wet rice noodles prepared in this embodiment is 13.29g / mm 2 The tensile distance when breaking occurred was 21.67 mm, the cooking yield was 194.5%, the cooking loss rate was 11.3%, and the broken strip rate was 15.8%.

[0125] Comparative Example 1

[0126] This comparative example relates to a method for producing fresh wet rice noodles under freezing conditions without using any additives, that is, only using rice starch for production.

[0127] Step 1: Weigh 15 g of rice starch and add 15 g of deionized water to prepare a starch suspension, add 45 g of boiling water, and stir to prepare a glutinous rice starch.

[0128] Step 2: Mix the paste obtained in step 1 with 82.5g of rice starch, knead into a smooth dough, cover with plastic wrap, and let stand at room temperature for 5 minutes.

[0129] Step 3: Use a noodle press to extrude the dough obtained in step 3 into rice noodles with a diameter of 3 mm. Steam the obtained rice noodles in boiling water for 5 seconds, remove them, cool them in cold water for 1 hour, remove them, wipe off the surface moisture, and freeze them in a refrigerator at -18°C for 48 hours.

[0130] Step 4: Determine the cooking characteristics, tensile strength, tensile distance when breaking, and breakage rate of the thawed rice noodles.

[0131] Implementation effect: the tensile strength of the rice flour prepared by this comparative example is 11.68 g / mm 2 The tensile distance when breaking occurred was 16.44 mm, the cooking yield was 180.6%, the cooking loss rate was 24.8%, and the broken strip rate was 20.0%.

[0132] Comparative Example 2

[0133] This comparative example relates to a method for producing fresh wet rice noodles under frozen conditions without using any additives. The method is similar to comparative example 1, except that the frozen storage time in step 3 is changed to 120 h.

[0134] Implementation effect: the tensile strength of the rice flour prepared by this comparative example is 9.59 g / mm 2 The tensile distance when breaking occurred was 13.94 mm, the cooking yield was 177.9%, the cooking loss rate was 26.1%, and the broken strip rate was 30.0%.

[0135] Comparative Example 3

[0136] This comparative example relates to a method for producing fresh wet rice noodles at room temperature without using any additives. The method is similar to comparative example 1, except that the frozen storage for 48 hours in step 3 is replaced by storage at room temperature for 48 hours.

[0137] Implementation effect: the tensile strength of the rice flour prepared by this comparative example is 9.24 g / mm 2 The tensile distance when breaking occurred was 12.32 mm, the cooking yield was 173.1%, the cooking loss was 28.3%, and the breaking rate was 32.0%.

[0138] Comparative Example 4

[0139] This comparative example relates to a method based on traditional production of fresh wet rice noodles under frozen conditions, i.e. using alum as an additive to improve the quality of fresh wet rice noodles after frozen storage.

[0140] Step 1: Weigh 15 g of rice starch and add 15 g of deionized water (water temperature is 40° C.) to prepare a starch suspension, add 45 g of boiling water, and stir to prepare a glutinous rice starch.

[0141] Step 2: Mix 300 mg of alum and 75 g of rice starch.

[0142] Step 3: Mix the rice starch and alum blend obtained in step 2 with the glutinous rice paste obtained in step 1 in a mass ratio of 1:1, knead into a smooth dough, cover with plastic wrap, and let stand at room temperature for 5 minutes.

[0143] Step 4: Use a noodle press to squeeze the dough obtained in step 3 into rice noodles with a diameter of 3 mm. Steam the obtained rice noodles in boiling water for 5 seconds, then remove them, cool them in cold water for 1 hour, remove them, wipe off the surface moisture, and freeze them in a refrigerator at -18°C for 48 hours.

[0144] Step 5: Determine the cooking characteristics, tensile strength, tensile distance when breaking, and breakage rate of the thawed rice noodles.

[0145] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 16.06 g / mm 2 The tensile distance when breaking occurred was 26.25 mm, the cooking yield was 191.1%, the cooking loss rate was 8.50%, and the broken strip rate was 11.3%.

[0146] Comparative Example 5

[0147] This comparative example relates to a method for producing fresh wet rice noodles under traditional freezing conditions. The method is similar to comparative example 4, except that the freezing storage time in step 4 is changed to 120 h.

[0148] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 15.35g / mm 2 The tensile distance when breaking occurred was 25.39 mm, the cooking yield was 189.8%, the cooking loss rate was 13.7%, and the broken strip rate was 16.3%.

[0149] Comparative Example 6

[0150] This comparative example relates to a method based on fresh wet rice noodles under traditional room temperature conditions. The method is similar to comparative example 3, except that the frozen storage for 48 hours in step 4 is changed to room temperature storage for 48 hours.

[0151] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 12.32 g / mm 2 The tensile distance when breaking occurred was 21.52 mm, the cooking yield was 189.6%, the cooking loss rate was 15.8%, and the broken strip rate was 17.5%.

[0152] Comparative Example 7

[0153] This comparative example relates to a method for improving the quality of fresh wet rice noodles under freezing conditions based on acetate corn starch.

[0154] Step 1: corn starch is mixed with deionized water to prepare a 40% starch milk, 3% sodium hydroxide is used to adjust the pH of the system to 8.4, the mixture is stirred for 15 minutes, 5% acetic anhydride by weight of the dry starch basis is added dropwise, and the mixture is reacted for one hour. During the reaction, 3% sodium hydroxide is used to adjust the pH of the system to 8.0-8.4. After the reaction, 0.5 mol / L hydrochloric acid is used to adjust the pH to 6.5. The mixture is filtered and washed, and dried in an oven at 37°C for 48 hours to obtain acetate corn starch.

[0155] Step 2: Evenly mix the acetate starch obtained in step 1 with 75 g of rice starch, wherein the amount of acetate starch added is 1% of the mass of the rice starch.

[0156] Step 3: Weigh 15 g of rice starch and add 15 g of deionized water (water temperature is 40° C.) to prepare a starch suspension, add 45 g of boiling water, and stir to prepare a glutinous rice starch.

[0157] Step 4: Knead the glutinous rice paste obtained in step 2 and the starch obtained in step 3 into a smooth dough (wherein the mass ratio of cooked glutinous rice paste to compound starch is 1:1), cover with plastic wrap, and let stand at room temperature for 5 minutes.

[0158] Step 5: Use a noodle press to extrude the dough obtained in step 5 into rice noodles with a diameter of 3 mm. Steam the obtained rice noodles in boiling water for 5 seconds, remove them, cool them in cold water for 1 hour, remove them, wipe off the surface moisture, and freeze them in a refrigerator at -18°C for 48 hours.

[0159] Step 6: Determine the cooking characteristics, tensile strength, tensile distance when breaking, and breakage rate of the thawed rice noodles.

[0160] Implementation effect: The measured median particle size of corn starch is 14.95 μm, which is larger than 10 μm and has a large difference from the median particle size of rice starch (5.79 μm).

[0161] The tensile strength of the rice flour prepared in this comparative example is 13.43 g / mm 2 The tensile distance when breaking occurred was 17.83 mm, the cooking yield was 190.4%, the cooking loss rate was 13.5%, and the broken strip rate was 15.0%.

[0162] Comparative Example 8

[0163] This comparative example relates to a method for improving the quality of fresh wet rice noodles under frozen conditions using acetate corn starch. The method is the same as that of comparative example 7, except that the amount of acetate corn starch added in step 2 is changed to 3% of the rice starch.

[0164] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 13.72g / mm 2The tensile distance when breaking occurred was 20.25 mm, the cooking yield was 194.7%, the cooking loss rate was 14.4%, and the broken strip rate was 10.0%.

[0165] Comparative Example 9

[0166] This comparative example relates to a method for improving the quality of fresh wet rice noodles under frozen conditions based on acetate corn starch. The method is the same as that of comparative example 7, except that the amount of acetate corn starch added in step 2 is changed to 5% of the rice starch.

[0167] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 13.94 g / mm 2 The tensile distance when breaking occurred was 21.68 mm, the cooking yield was 193.1%, the cooking loss rate was 14.2%, and the broken strip rate was 12.5%.

[0168] Comparative Example 10

[0169] This comparative example relates to a method for improving the quality of fresh wet rice noodles under frozen conditions based on corn starch acetate. The method is the same as that of comparative example 7, except that the frozen storage time in step 5 is changed to 120 hours.

[0170] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 9.83g / mm 2 The tensile distance when breaking occurred was 14.13 mm, the cooking yield was 179.4%, the cooking loss rate was 25.5%, and the broken strip rate was 27.0%.

[0171] Comparative Example 11

[0172] This comparative example relates to a method for improving the quality of fresh wet rice noodles under frozen conditions based on acetate corn starch. The method is the same as that of comparative example 8, except that the frozen storage time in step 5 is changed to 120 hours.

[0173] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 9.75g / mm 2 The tensile distance when breaking occurred was 14.25 mm, the cooking yield was 180.1%, the cooking loss rate was 24.7%, and the broken strip rate was 25.0%.

[0174] Comparative Example 12

[0175] This comparative example relates to a method for improving the quality of fresh wet rice noodles under frozen conditions based on acetate corn starch. The method is the same as that of comparative example 9, except that the frozen storage time in step 5 is changed to 120 hours.

[0176] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 10.04g / mm 2The tensile distance when breaking occurred was 14.68 mm, the cooking yield was 179.3%, the cooking loss rate was 24.2%, and the broken strip rate was 26.5%.

[0177] Comparative Example 13

[0178] This comparative example relates to a method for improving the quality of fresh wet rice noodles under freezing conditions based on acetate tapioca starch. The method is the same as that of comparative example 7, except that the starch in step 1 is replaced with tapioca starch.

[0179] Implementation effect: The median particle size of cassava starch was measured to be 15.79 μm, which is larger than 10 μm and has a large difference from the median particle size of rice starch (5.79 μm).

[0180] The tensile strength of the rice flour prepared in this comparative example is 13.12 g / mm 2 The tensile distance when breaking occurred was 17.52 mm, the cooking yield was 192.6%, the cooking loss rate was 14.9%, and the broken strip rate was 14.5%.

[0181] Comparative Example 14

[0182] This comparative example relates to a method for improving the quality of rice noodles by freezing fresh rice noodles using acetate tapioca starch. The method is the same as that of comparative example 8, except that the starch in step 1 is replaced with tapioca starch.

[0183] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 13.66 g / mm 2 The tensile distance when breaking occurred was 23.25 mm, the cooking yield was 195.7%, the cooking loss rate was 13.4%, and the broken strip rate was 12.5%.

[0184] Comparative Example 15

[0185] This comparative example relates to a method for improving the quality of fresh wet rice noodles under freezing conditions based on acetate tapioca starch. The method is the same as that of comparative example 9, except that the starch in step 1 is replaced with tapioca starch.

[0186] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 12.73 g / mm 2 The tensile distance when breaking occurred was 21.83 mm, the cooking yield was 194.4%, the cooking loss rate was 14.5%, and the broken strip rate was 15.0%.

[0187] Comparative Example 16

[0188] This comparative example relates to a method for improving the quality of fresh wet rice noodles under frozen conditions based on acetate tapioca starch. The method is the same as that of comparative example 13, except that the frozen storage time in step 5 is changed to 120 hours.

[0189] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 9.77g / mm 2 The tensile distance when breaking occurred was 14.59 mm, the cooking yield was 180.9%, the cooking loss rate was 25.7%, and the broken strip rate was 22.5%.

[0190] Comparative Example 17

[0191] This comparative example relates to a method for improving the quality of fresh wet rice noodles under frozen conditions based on acetate tapioca starch. The method is the same as that of comparative example 14, except that the frozen storage time in step 5 is changed to 120 hours.

[0192] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 9.88g / mm 2 The tensile distance when breaking occurred was 14.57 mm, the cooking yield was 179.3%, the cooking loss rate was 24.9%, and the broken strip rate was 25.5%.

[0193] Comparative Example 18

[0194] This comparative example relates to a method for improving the quality of fresh wet rice noodles under frozen conditions based on acetate tapioca starch. The method is the same as that of comparative example 15, except that the frozen storage time in step 5 is changed to 120 hours.

[0195] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 10.13 g / mm 2 The tensile distance when breaking occurred was 14.87 mm, the cooking yield was 180.3%, the cooking loss rate was 25.1%, and the broken strip rate was 27.0%.

[0196] By comparison, it can be seen that using acetate oats and buckwheat starch with smaller particle size is easier to form a stable gel network structure than using acetate corn and cassava starch with larger particle size to produce fresh wet rice noodles, which enhances the ability of fresh wet rice noodles to resist ice crystal damage during frozen storage. Therefore, this quality difference becomes greater as the freezing time increases.

[0197] Comparative Example 19

[0198] This comparative example relates to a method for improving the quality of fresh wet rice noodles at room temperature using acetate corn starch. The method is the same as that of comparative example 7, except that the 48-hour frozen storage in step 5 is replaced with 48-hour room temperature storage.

[0199] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 9.71g / mm 2The tensile distance when breaking occurred was 15.93 mm, the cooking yield was 181.4%, the cooking loss rate was 22.5%, and the broken strip rate was 21.0%.

[0200] Comparative Example 20

[0201] This comparative example relates to a method for improving the quality of fresh wet rice noodles at room temperature using acetate corn starch. The method is the same as that of comparative example 8, except that the 48-hour frozen storage in step 5 is replaced with 48-hour room temperature storage.

[0202] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 9.47g / mm 2 The tensile distance when breaking occurred was 15.25 mm, the cooking yield was 185.7%, the cooking loss rate was 17.4%, and the broken strip rate was 18.0%.

[0203] Comparative Example 21

[0204] This comparative example relates to a method for improving the quality of fresh wet rice noodles at room temperature using acetate corn starch. The method is the same as that of comparative example 9, except that the 48-hour frozen storage in step 5 is replaced with 48-hour room temperature storage.

[0205] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 9.69g / mm 2 The tensile distance when breaking occurred was 13.71 mm, the cooking yield was 179.1%, the cooking loss rate was 18.2%, and the broken strip rate was 17.5%.

[0206] Comparative Example 22

[0207] This comparative example relates to a method for improving the quality of fresh wet rice noodles at room temperature using acetate tapioca starch. The method is the same as that of comparative example 13, except that the 48-hour frozen storage in step 5 is replaced with 48-hour room temperature storage.

[0208] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 11.92g / mm 2 The tensile distance when breaking occurred was 15.79 mm, the cooking yield was 181.9%, the cooking loss rate was 23.1%, and the broken strip rate was 19%.

[0209] Comparative Example 23

[0210] This comparative example relates to a method for improving the quality of fresh wet rice noodles at room temperature using acetate tapioca starch. The method is the same as that of comparative example 14, except that the 48-hour frozen storage in step 5 is replaced with 48-hour room temperature storage.

[0211] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 11.71 g / mm2 The tensile distance when breaking occurred was 16.41 mm, the cooking yield was 186.7%, the cooking loss rate was 15.9%, and the broken strip rate was 17.5%.

[0212] Comparative Example 24

[0213] This comparative example relates to a method for improving the quality of fresh wet rice noodles at room temperature based on acetate tapioca starch. The method is the same as that of comparative example 15, except that the 48-hour frozen storage in step 5 is replaced with 48-hour room temperature storage.

[0214] Implementation effect: The tensile strength of the rice flour prepared in this comparative example is 9.53g / mm 2 The tensile distance when breaking occurred was 13.57 mm, the cooking yield was 177.4%, the cooking loss rate was 16.5%, and the broken strip rate was 18%.

[0215] Comparative Example 25

[0216] This comparative example relates to a method for improving the quality of fresh wet rice noodles under freezing conditions by compounding starch acetate, distarch phosphate, and acetylated distarch phosphate. The starch acetate, distarch phosphate, and acetylated distarch phosphate are all modified from cassava starch. The method is identical to that of Comparative Example 4, differing only in that the alum in step 2 is replaced with a compounded improver of starch acetate, distarch phosphate, and acetylated distarch phosphate, in a ratio of 1:1:2. The compounded improver is added in an amount of 10% of the mass of the rice starch.

[0217] Implementation effect: The tensile strength of the rice noodles prepared in this comparative example is 14.12 g / mm 2 The tensile distance when breaking occurred was 21.41 mm, the cooking yield was 197.7%, the cooking loss rate was 16.4%, and the broken strip rate was 15%.

[0218] Table 1 Tensile strength, tensile distance, cooking characteristics and breaking rate of fresh wet rice noodles stored at -18℃ for 48h

[0219]

[0220]

[0221] Different letters in the same column indicate significant differences (p<0.05).

[0222] Table 2 Tensile strength, tensile distance, cooking characteristics and breaking rate of fresh wet rice noodles stored at -18℃ for 120h

[0223]

[0224]

[0225] Different letters in the same column indicate significant differences (p<0.05).

[0226] Table 3 Tensile strength, tensile distance, cooking characteristics and breaking rate of fresh wet rice noodles stored at room temperature for 48 h

[0227]

[0228] Different letters in the same column indicate significant differences (p<0.05).

[0229] It can be seen from Table 1 that compared with Comparative Example 1, the tensile strength and cooking yield of all embodiments are significantly improved, and the cooking loss rate and broken rate are significantly reduced. Among them, the tensile distance of Examples 1, 2, 3, and 6 is significantly greater than that of Comparative Example 1. This shows that the quality of frozen fresh wet rice noodles can be significantly improved by adding acetate starch to produce fresh wet rice noodles. Compared with Comparative Example 2, each embodiment has different degrees of improvement or optimization in terms of tensile strength, cooking yield, cooking loss rate and broken rate. The tensile strength of Comparative Example 4 is (16.06±0.10g / mm 2 ), the tensile distance is (26.25±0.24mm), the cooking rate is (191.1±1.40%), the cooking loss rate is (8.50±0.42%), the broken rate is (11.3±0.02%), and the tensile strength of Example 5 is (17.39±0.54g / mm 2 ) is significantly better than Comparative Example 2, showing stronger mechanical properties; Example 4 has a significant improvement in cooking yield (210.0±0.77%), while the cooking loss rate (7.90±0.37%) is also slightly lower than Comparative Example 4, showing better cooking properties; Example 2 has a better tensile strength (16.63±0.47g / mm 2) and cooking yield (198.2±0.64%) are better than those of Comparative Example 2. At the same time, the cooking loss rate (11.0±0.27%) is slightly higher, but still within an acceptable range, and the overall performance is relatively balanced. In general, Example 4 and Example 5 significantly exceed Comparative Example 2 in cooking performance and tensile strength, respectively, while Example 2 performs well in comprehensive performance, providing a better alternative to Comparative Example 2. This shows that acetate starch can replace alum to produce fresh wet rice noodles that still maintain good quality after freezing. Compared with Comparative Examples 7, 8, 9, 13, 14, and 15, the tensile strength and cooking yield of all examples are significantly improved, and the cooking yield and broken rice rate are significantly reduced. This shows that using starch with a particle size similar to that of rice starch for acetylation and using the obtained acetate starch to assist in the production of fresh wet rice noodles can obtain fresh wet rice noodles with better quality. All the examples, compared with Comparative Example 25, have significant advantages in tensile strength, tensile distance, cooking characteristics, and broken rate, indicating that the composite improver used to improve the quality of fresh wet rice noodles at room temperature is not as effective as the one using acetate starch similar to rice starch particle size under the conditions of frozen storage. As shown in Table 2, the quality of fresh wet rice noodles without the addition of improver deteriorates seriously after 120h of frozen storage, while Examples 7-12 using acetate starch similar to rice starch particle size as improver can still maintain good quality, and have significant advantages compared with Comparative Examples 10-12 and Comparative Examples 16-18 using acetate corn starch and acetate tapioca starch as improvers, indicating that the fresh wet rice noodles produced using acetate starch similar to rice starch particle size still have good quality after a period of frozen storage. As shown in Table 3, the quality of unfrozen fresh wet rice noodles decreased significantly after 48 hours of storage at room temperature. However, fresh wet rice noodles produced with acetate starch, which has a particle size similar to that of rice starch, still had significant advantages over fresh wet rice noodles produced with acetate corn starch and acetate cassava starch. In summary, fresh wet rice noodles produced with acetate starch, which has a particle size similar to that of rice starch, have obvious advantages over other improvers and are more adaptable to long-term storage in low-temperature freezing.

[0230] The acetate starch used in the present invention is composed of oat starch and buckwheat starch, both of which have a particle size of less than 10 μm, which is similar to the particle size of rice starch, so that the composite system has a consistent water absorption rate and expansion behavior during the gelatinization process. The introduction of acetyl groups promotes the unzipping and dispersion of starch molecular chains, so that a uniform amorphous structure is formed after gelatinization, and the acetyl groups are evenly distributed in the system. During the cooling and regeneration process, the dispersed starch chains are easily entangled to form a dense and uniform gel network structure; and during the freezing process, this structure effectively inhibits the formation and growth of ice crystals, reducing their damage to the microstructure of rice noodles, thereby enhancing the toughness and ductility of fresh wet rice noodles after freezing, slowing down the hardening trend, and reducing the breakage rate. In addition, the presence of acetyl groups weakens the interaction between starch chains during the thawing process, reduces the dehydration phenomenon of the gel structure, and enables the fresh wet rice noodles after thawing to still maintain a high water content and dense structure, thereby improving the water retention capacity during the cooking process, reducing the leaching of amylose, and thus improving the cooking yield and reducing the cooking loss. In summary, this technology significantly improves the toughness, ductility and cooking resistance of frozen fresh wet rice noodles, effectively improving its taste and overall quality, and better meeting consumer demand.

[0231] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and that persons skilled in the art may make various changes or modifications within the scope of the claims without affecting the essence of the present invention. The embodiments of the present invention and the features of the embodiments may be combined in any manner unless there is a conflict.

Claims

1. A method for preparing alum-free frozen fresh wet rice noodles based on acetate starch, characterized in that: The method comprises the following steps: A. Preparation of starch acetate: Acetylation of cereal starch; B. Preparation of glutinous rice paste: rice starch is added to water to prepare a starch suspension, boiling water is added to the suspension, and stirring is performed to prepare glutinous rice paste; C. Preparation of compound starch: Compounding and mixing the acetate starch obtained in step A with rice starch; D. Preparation of dough: Knead the cooked starch obtained in step B and the compound starch obtained in step C into a smooth dough and let it stand; E. Preparation of fresh wet rice noodles: Extrude the dough obtained in step D into rice noodles, and then remove them after steaming; F. Cooling and freezing: Cool the fresh wet rice noodles obtained in step E in cold water, remove them from the rice noodles, drain them / wipe off the surface moisture, and freeze them.

2. The preparation method according to claim 1, characterized in that The cereal starch is buckwheat starch, oat starch or a combination of the two.

3. The preparation method according to claim 2, characterized in that The cereal starch is prepared by soaking cereals in alkali solution overnight, washing to remove the alkali solution, crushing and sieving, centrifuging to remove the supernatant and protein layer, and repeatedly washing with water until the starch suspension is neutral and no protein residue is left; suspending the starch in ethanol, filtering, drying, and grinding and sieving.

4. The preparation method according to claim 3, characterized in that Include at least one of the following technical features: S1, the alkali solution is 3-4g / L sodium hydroxide solution; S2, crushed through 100-200 mesh sieve; S3, filter and dry for 48 to 60 hours; S4. After grinding, pass through 80-100 mesh sieve.

5. The preparation method according to claim 1, characterized in that The modification agent used in the acetylation treatment is acetic anhydride, and the amount used is 3-5% of the mass fraction of the dry basis of the cereal starch.

6. The preparation method according to claim 5, characterized in that The acetylation treatment comprises: A1. Mix corn starch with deionized water to make a 40% starch emulsion. Adjust the pH of the system to 8.2-8.4 with sodium hydroxide and stir for 10-20 minutes. A2. Add acetic anhydride dropwise and react for 45 min-1 h. During the reaction, use sodium hydroxide to adjust the pH of the system to 8.0-8.

4. After the reaction, use hydrochloric acid to adjust the pH to 6.5±0.

1. Filter, wash, and dry to obtain acetate starch.

7. The preparation method according to claim 1, characterized in that In step B, the water temperature for preparing the starch suspension is 40-45° C., and the mass ratio of rice starch to water is 1:1-1:

5.

8. The preparation method according to claim 1, characterized in that In step C, the added amount of starch acetate is 1% to 5% of the mass of rice starch.

9. The preparation method according to claim 1, characterized in that In step D, the mass ratio of cooked starch to compound starch is 4:5 to 6:

5.

10. The preparation method according to claim 1, characterized in that In step F, the cooling temperature is 20-25° C., and the cooling time is 45-60 minutes; the freezing temperature is -12--18° C., and the freezing time is 36-48 hours.

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