Fresh and wet rice noodles and preparation method thereof

Abstract

The invention belongs to the technical field of food processing, and discloses fresh and wet rice noodles and a preparation method thereof.The preparation method specifically comprises the steps that rice milk, chitosan and edible organic acid are mixed and then heated and extruded to obtain rice noodles; soaking the rice noodles in an ozone-containing aqueous solution to obtain fresh wet rice noodles; the total dosage of the chitosan and the edible organic acid is 0.05-2wt% of the weight of the rice milk; according to the fresh and wet rice noodles disclosed by the invention, the chitosan and the edible organic acid are added in the preparation process, and the fresh and wet rice noodles are soaked in the ozone water, so that the quality of the fresh and wet rice noodles can be remarkably improved and the shelf life of the fresh and wet rice noodles can be remarkably prolonged by utilizing the synergistic effect among the chitosan, the edible organic acid and the ozone water; and the quality stability of the fresh and wet rice noodles in the shelf life is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing and discloses fresh wet rice noodles and a preparation method thereof. Background Art

[0002] Fresh wet rice noodles are made from rice through a process of soaking, steaming, and layering. They are widely favored by consumers for their smooth texture and nutritious nutrition. Fresh wet rice noodles generally have a moisture content above 50%. Sensory evaluations have shown that noodles with a moisture content of 60-63.5% score the highest. However, higher moisture content is associated with a shorter shelf life, a faster decline in sensory scores, and a higher increase in cooking loss, breakage rate, and acidity, as well as increased microbial growth. Texture analysis shows that higher moisture content reduces hardness, stickiness, and chewiness, resulting in a shelf life of less than 24 hours at room temperature, severely restricting their industrial production and distribution range.

[0003] Currently, the industry primarily utilizes the following preservation technologies: Chemical preservatives: Adding potassium sorbate, sodium benzoate, and other preservatives inhibits microbial growth, but chemical preservatives carry the risk of chemical residues and are inconsistent with the development trend of green food. High-temperature sterilization: Extending shelf life through high-temperature treatment, but prolonged high-temperature treatment of fresh wet rice noodles that have undergone secondary maturation can easily destroy the natural flavor and texture of the rice noodles. Modified atmosphere packaging: Using nitrogen / carbon dioxide to replace the atmosphere within the packaging has a certain inhibitory effect on aerobic bacteria, but has limited effectiveness against anaerobic spoilage bacteria. Low-temperature refrigeration: Using cold chain transportation to maintain a temperature of 4-8°C, however, this is energy-intensive and can easily lead to starch retrogradation and moisture migration. These measures merely improve the shelf life of rice noodles, but fail to address the problem of high moisture content in fresh wet rice noodles, which deteriorates in quality (texture and cooking properties) with extended storage.

[0004] Therefore, the technical problem solved by the present invention is: how to prepare a fresh wet rice noodle with good quality, long shelf life and stable quality during the shelf life. Summary of the Invention

[0005] The present invention aims to provide a method for preparing fresh wet rice noodles. During the preparation process, chitosan and an edible organic acid aqueous solution are added to raw materials, and ozone water soaking is performed. By utilizing the synergistic effect of chitosan, organic acid and ozone water, not only the quality of the fresh wet rice noodles can be significantly improved, but also the shelf life of the fresh wet rice noodles can be significantly extended, and the quality stability of the fresh wet rice noodles during the shelf life can be increased.

[0006] At the same time, the invention also provides fresh wet rice noodles obtained by the preparation method.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for preparing fresh wet rice noodles, characterized in that rice milk, chitosan, and an edible organic acid are mixed, heated, and extruded to obtain rice noodles; the rice noodles are soaked in an aqueous solution containing ozone to obtain the fresh wet rice noodles;

[0009] The amount of chitosan and edible organic acid used is equivalent to 0.05-2 wt% of the weight of rice milk.

[0010] In the present invention, chitosan and edible organic acid are added to the raw materials, and ozone water is soaked. The synergistic effect of chitosan, organic acid and ozone water is utilized to not only significantly improve the quality of the fresh wet rice noodles, but also significantly prolong the shelf life of the fresh wet rice noodles, and increase the quality stability of the fresh wet rice noodles during the shelf life. It is speculated that the possible mechanism is:

[0011] Chitosan (a positively charged cationic polysaccharide) forms a network structure with negatively charged starch molecules (especially the phosphate groups of amylopectin) or proteins (such as gluten) in rice flour through electrostatic interactions. This network fills the gaps left by starch gelatinization and reduces the disordered arrangement of starch granules. This physical crosslinking inhibits the rapid rearrangement of starch molecules during cooling (known as "retrogradation"), thereby improving the elasticity and water retention of rice flour (reducing the dryness and hardness caused by water loss). Furthermore, the hydroxyl and amino groups on the chitosan molecular chains form hydrogen bonds with water molecules, slowing water evaporation and maintaining the softness of the rice flour. Edible organic acids can slow the rapid aggregation of components such as alcohol-soluble proteins in rice flour, preventing a hard texture. They can also accelerate the water absorption and expansion of starch, forming a more uniform gelatinization structure and improving the softness and transparency of the rice flour. Ozone, on the other hand, creates a moderately hydrophilic microenvironment on the surface of the rice flour, balancing water retention and surface smoothness (preventing sticking).

[0012] In terms of antibacterial properties, the semipermeable membrane formed by chitosan on the surface of rice noodles can prevent the attachment and invasion of external microorganisms (such as mold spores). At the same time, its cationic properties can combine with the negatively charged phospholipids on the microbial cell membrane, destroying the membrane structure and causing the leakage of intracellular substances (antibacterial properties). At the same time, organic acids (such as lactic acid) can penetrate the microbial cell membrane and dissociate H + , causing a decrease in intracellular pH, inhibiting the activity of key enzymes (such as ATPase and respiratory chain enzymes), and blocking energy metabolism. The strong oxidizing properties of ozone water can directly damage microbial cell walls, membranes, and genetic material. It is highly effective in killing most microorganisms (including acid-resistant bacteria). Ozone water, chitosan membranes, and organic acids form a triple synergistic protective mechanism of "physical barrier + chemical inhibition + oxidative inactivation," effectively extending the shelf life of rice noodles.

[0013] Preferably, the edible organic acid is one or more combinations of lactic acid, citric acid, acetic acid and malic acid.

[0014] Preferably, the solids in the rice milk are mainly rice raw materials; the content of the rice raw materials is not less than 50wt% of the solid weight.

[0015] More preferably, the fixed material further contains starch raw materials;

[0016] The rice raw material is early indica rice;

[0017] The starch raw material is one or more combinations of wheat starch, potato starch and corn starch.

[0018] More preferably, the content of the rice raw material is 70-100 wt % of the solid weight.

[0019] Preferably, the chitosan is equivalent to 0.05-1.0 wt% of the total amount of rice milk; and the organic acid is equivalent to 0.01-0.5 wt% of the total amount of rice milk.

[0020] Preferably, the concentration of ozone in the ozone-containing aqueous solution is 0.2 to 0.4 mg / L; and the soaking time is 1 to 5 minutes.

[0021] Preferably, a heat sterilization operation is performed after soaking; the heat sterilization temperature is 90° C. and the time is 30 minutes.

[0022] Preferably, when preparing the rice milk, the amount of water used is 20 to 65 wt % of the total mass of the rice milk.

[0023] In addition, the invention also discloses fresh wet rice noodles, which are prepared by the method described above.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The fresh wet rice noodles of the present invention are prepared by adding chitosan and edible organic acid and soaking in ozone water. The synergistic effect of the chitosan, edible organic acid and ozone water is utilized to not only significantly improve the quality of the fresh wet rice noodles, but also significantly extend the shelf life of the fresh wet rice noodles and increase the quality stability of the fresh wet rice noodles during the shelf life. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a photo of the fresh rice noodles of Example 3;

[0027] Figure 2 This is a photo of the fresh rice noodles of Comparative Example 4. DETAILED DESCRIPTION

[0028] Below in conjunction with embodiments of the present invention, technical scheme of the present invention is clearly and completely described, it is obvious that described embodiment is only a part of embodiment of the present invention, rather than whole embodiment. Based on the embodiment in the present invention, every other embodiment obtained by those of ordinary skill in the art without making creative work premise all falls within the scope of protection of the present invention. Reagents used or instrument do not indicate manufacturer, all are conventional products that can be purchased by commercially available acquisition.

[0029] Part 1 Preparation of fresh wet rice noodles using early indica rice as raw material

[0030] Examples 1 to 5 and Comparative Examples 1 to 3;

[0031] The fresh wet rice noodles of the above-mentioned embodiment and comparative example are prepared with reference to the following method:

[0032] A method for preparing fresh wet rice noodles comprises the following steps:

[0033] Step 1: preparing rice milk, using early indica rice as a raw material, preparing rice milk; the weight ratio of water to early indica rice is 55:45;

[0034] Step 2: adding chitosan and organic acid to rice milk, stirring and dispersing them evenly to prepare compound rice milk;

[0035] Step 3: steaming and extruding the composite rice slurry to obtain rice flour; the steaming temperature is 100° C.;

[0036] Step 4: Soak the rice noodles in ozone water until the ozone water covers the surface of the rice noodles and soak for a period of time; then vacuum pack the rice noodles in a packaging bag (leaving some air), and after packaging, sterilize the rice noodles in a water bath at 90°C for 30 minutes.

[0037] Chitosan, organic acid, ozone concentration and immersion time can be referred to Table 1; the chitosan used in the present invention is acid-soluble chitosan (deacetylation degree ≥ 90%);

[0038] In Table 1, the units of chitosan and organic acid are wt%, based on the weight of rice milk as 100%.

[0039] Table 1 Formulation process

[0040]

[0041] Example 11

[0042] The process is substantially the same as in Example 2, except that the weight ratio of water to early indica rice is 65:35.

[0043] Example 12

[0044] The process is substantially the same as in Example 2, except that the weight ratio of water to early indica rice is 30:70.

[0045] Comparative Example 5

[0046] The method is substantially the same as Example 2, except that food-grade chitosan lactate is used instead of chitosan and lactic acid; the amount of food-grade chitosan lactate used is equivalent to 0.2 wt % of the weight of rice milk.

[0047] Performance Testing

[0048] The fresh wet rice noodles obtained by each embodiment and comparative example were tested according to the following method:

[0049] Shelf life: The expiration of the shelf life of fresh wet rice noodles is usually determined by excessive microorganisms (such as total colony count, coliform group, pathogenic bacteria) causing the product to become moldy, bulge, or have key quality deterioration (such as decreased viscosity, increased breakage rate, and the generation of odor).

[0050] Hardness and springiness were measured using a texture analyzer. Three 10 cm long, undamaged brown rice noodles were steamed in boiling water for 2.5 minutes, then dried with filter paper. The noodles were then laid parallel to each other on the texture analyzer's test surface. TPA was used for the measurement using the following parameters: probe P / 36R, speed before, during, and after the test at 2.00 mm / s, strain rate 75%, and trigger force 5.0 g. Hardness and springiness were measured with at least five replicates for each sample.

[0051] Rehydration time: Weigh 50g of dry rice flour and place it in 250mL of boiling water, keeping it at a slight boil;

[0052] Take a grain of rice noodle every 30 seconds and press the center lightly with your finger. If there is no hard core, the rehydration is complete.

[0053] The total time from start to complete rehydration was recorded;

[0054] Broken rice noodles: Pick 20 pieces of 15cm long brown rice noodles without mechanical damage, place them in a 500mL beaker and add 300mL boiling water, heat on an electric stove and keep it slightly boiling, cook for 2.5min and then use a sieve to remove the supercooled water for 30s, pick out the brown rice noodles with a length of ≥7.5cm and weigh them as m1, and weigh the brown rice noodles with a length of <7.5cm and weigh them as m2, and calculate the broken rice noodles rate according to the formula: Broken rice noodles rate = m2 / (m1+m2)×100%

[0055] Cooking loss: 50 g of dry rice flour was placed in 250 mL of distilled water and cooked in a boiling water bath for 10 minutes (adjust the time according to the product instructions). The cooking liquid was filtered, and the filtrate was collected and dried to constant weight (105°C oven). Calculation: Cooking loss (%) = (filtrate dry weight / initial weight of dry rice flour) × 100%.

[0056] Water absorption rate: Take 50g of dry rice noodles, cook according to the rehydration conditions, drain the surface water (within 10 seconds), and weigh;

[0057] Calculation of the results: Water absorption (%) = (weight after cooking - weight of dry rice noodles) / weight of dry rice noodles × 100%.

[0058] The test results are shown in Table 2;

[0059] The fresh wet rice noodles obtained in Example 2, Examples 7-10 and Comparative Examples 1-4 were stored for 15 days and then subjected to the above test again. The results are shown in Table 3.

[0060] Table 2 Fresh wet rice noodle test data

[0061]

[0062] Table 3 Fresh wet rice flour test data after storage for 15 days

[0063]

[0064]

[0065] Result analysis:

[0066] As can be seen from the data analysis of table 2, the fresh wet rice flour that the present invention makes, the shelf life reaches 6 months, and quality has been significantly improved, particularly embodiment 4, its hardness is 4095g, and elasticity is 99.1%, and the rehydration time only needs 2.8min, and the broken rate is 0.7%, and the boiling loss is 3.12%, and the water absorption rate is 36.7%; Draw by the data of embodiment 1-2 embodiment 7-10, no matter edible organic acid adopts lactic acid, citric acid, acetic acid or malic acid, it has good effect, and wherein the best effect is lactic acid.

[0067] Comparative Example 1 did not add edible organic acid to the rice noodle raw materials, Comparative Example 2 did not add chitosan to the rice noodle raw materials, the rice noodles of Comparative Example 3 were not soaked in ozone water during production, Comparative Example 4 was a blank control group, and Comparative Example 5 replaced the chitosan lactate solution with an equal mass of chitosan; the shelf life of the rice noodles of Comparative Examples 1 and 2 was 30 days, the shelf life of the rice noodles of Comparative Examples 3 and 5 was 60 days, and the shelf life of the blank control group of Comparative Example 4 was only 15 days, all of which were much less than 6 months of the embodiment; and in terms of quality, each performance was also much lower than that of Example 2.

[0068] Data analysis of Table 3 shows that after storing the fresh wet rice flour of Example 2, Examples 7-10 and Comparative Examples 1-5 for 15 days, the various performance changes of the fresh wet rice flour of Example 2 and Examples 7-10 are all minimal, particularly Example 2; while the hardness, rehydration time, broken rate, and cooking loss of the fresh wet rice flour of Comparative Examples 1-5 significantly increase, while elasticity and water absorption significantly decrease.

[0069] Figure 1 This is a photo of the fresh rice noodles of Example 3. Figure 2 This is a photo of the fresh rice noodles of Comparative Example 4.

[0070] In summary, the fresh wet rice noodles of the present invention are added with chitosan and edible organic acid during the preparation process, and are soaked in ozone water. The synergistic effect among chitosan, edible organic acid and ozone water is utilized, which not only can significantly improve the quality of the fresh wet rice noodles, but also can significantly extend the shelf life of the fresh wet rice noodles, and increase the quality stability of the fresh wet rice noodles during the shelf life.

[0071] Part 2 Preparation of fresh wet rice noodles using early indica rice as the main raw material

[0072] In rice noodle production, using other starch raw materials as one of the auxiliary starches is an important way to improve the taste of rice noodles. In this section, the effects of the additives and ozone soaking process of the present invention on the performance are further verified when using compound starch raw materials.

[0073] The preparation process, concentrations of chitosan, organic acid, and ozone solution, and the soaking operation are the same as those in Example 2;

[0074] The difference is that the compound starch raw materials are different, as shown in Table 4; the units in Table 4 are weight percentages;

[0075] Table 4: Recipe table;

[0076] Early Indica Rice corn starch potato starch wheat starch Example 11 70 30 0 0 Example 12 50 30 20 0 Example 13 60 0 20 20

[0077] The test method is the same as the first part;

[0078] The test results refer to Table 5;

[0079] Table 5 Test results

[0080]

[0081] As can be seen from the results in Table 5, the use of the additives and the ozone solution soaking process of the present invention are not affected by the type of raw materials, and can achieve good results in different types of rice noodles.

[0082] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A method for preparing fresh wet rice noodles, characterized in that, Rice milk, chitosan and edible organic acid are mixed, heated and extruded to obtain rice noodles; the rice noodles are soaked in an ozone-containing aqueous solution to obtain fresh wet rice noodles; The total amount of chitosan and edible organic acid is equivalent to 0.05-2 wt% of the weight of rice milk.

2. The preparation method according to claim 1, characterized in that The edible organic acid is one or more combinations of lactic acid, citric acid, acetic acid and malic acid.

3. The preparation method according to claim 1, characterized in that The solid matter in the rice milk is mainly composed of rice raw material; the content of the rice raw material is not less than 50wt% of the weight of the solid matter.

4. The preparation method according to claim 3, characterized in that The fixed material also contains starch raw materials; The rice raw material is early indica rice; The starch raw material is one or more combinations of rice starch, wheat starch, potato starch and corn starch.

5. The preparation method according to claim 3, characterized in that The content of the rice raw material is 70-100 wt% of the solid weight.

6. The preparation method according to claim 1, characterized in that The chitosan is equivalent to 0.05-1.0 wt% of the total amount of rice milk; and the organic acid is equivalent to 0.01-0.5 wt% of the total amount of rice milk.

7. The preparation method according to claim 1, characterized in that The concentration of ozone in the ozone-containing aqueous solution is 0.2-0.4 mg / L; and the soaking time is 1-5 minutes.

8. The preparation method according to claim 1, characterized in that After soaking, a heat sterilization operation is performed; the heat sterilization temperature is 90° C. and the time is 30 minutes.

9. The preparation method according to claim 1, characterized in that When the rice milk is prepared, the amount of water used is 20 to 65 wt % of the total weight of the rice milk.

10. A fresh wet rice noodle, characterized in that The method is prepared according to any one of claims 1 to 9.

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