Biological preservation method for prolonging shelf life of fresh and wet soda noodles and method for inhibiting starch retrogradation of fresh and wet soda noodles

Abstract

The invention discloses a biological preservation method for prolonging the shelf life of fresh and wet soda noodles and a method for inhibiting starch retrogradation of the fresh and wet soda noodles, and belongs to the technical field of food processing. The method comprises the following steps: S1, disinfection: sterilizing and disinfecting a noodle making environment to ensure that the noodle making environment is clean and tidy; s2, burdening: respectively dissolving epsilon-polylysine hydrochloride and dietary alkali in water, fully and uniformly stirring to prepare dough kneading water, and uniformly mixing sucrose ester with flour; s3, dough kneading: slowly pouring dough kneading water containing epsilon-polylysine hydrochloride into the flour containing sucrose ester for multiple times, and kneading the dough by using a dough kneading machine until the dough is in a loose flocculent shape; and S4, noodle making: making the dough into noodles. Growth and reproduction of microorganisms can be inhibited, the starch retrogradation phenomenon in the fresh and wet sodium carbonate storage process is inhibited, and the shelf life of the fresh and wet sodium carbonate is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, in particular to a biological preservation method for prolonging the shelf life of fresh wet alkaline noodles and inhibiting the retrogradation of starch thereof. Background Art

[0002] The production process of fresh wet alkaline noodles does not involve drying, frying, freezing and other processes, resulting in less nutritional loss. The original flavor of the alkaline noodles is retained to the greatest extent, and the reprocessing time is short. It is convenient and quick to eat, which meets the pursuit of natural taste of food by contemporary people in the fast-paced life.

[0003] However, due to the high moisture content and rich nutrients of fresh alkaline noodles, they are easily affected by microorganisms during storage and become spoiled, which shortens the shelf life of noodles and becomes a bottleneck for large-scale production. At the same time, fresh alkaline noodles are pre-cooked, and starch is easily retrograded during storage, affecting the taste and edible quality of noodles. Summary of the invention

[0004] In view of this, it is necessary to provide a biological preservation method for extending the shelf life of fresh wet alkaline noodles and inhibiting the starch retrogradation thereof, so as to solve the problem that the existing fresh wet alkaline noodles are prone to deterioration and starch retrogradation during storage.

[0005] The present invention provides a biological preservation method for extending the shelf life of fresh wet alkaline noodles and inhibiting starch retrogradation thereof, comprising the following steps:

[0006] S1: Disinfection: Sterilize and disinfect the noodle making environment to ensure that it is clean and tidy;

[0007] S2: Ingredients: dissolve ε-polylysine hydrochloride and edible alkali in water respectively, stir well to make dough water, and mix sucrose ester and flour evenly;

[0008] S3: Kneading dough: slowly pour the kneading water containing ε-polylysine hydrochloride into the flour containing sucrose ester several times, and knead the dough with a dough mixer until the dough is loose and flocculent;

[0009] S4: Noodle making: making the dough into noodles.

[0010] Furthermore, step S4 also includes the following sub-steps:

[0011] S41: Proofing: Compound-calender the dough for one or two times, and place the rolled dough at a suitable temperature for a set time to ensure that the gluten and starch in the dough are fully hydrated;

[0012] S42: calendering: calendering and cutting the noodle floss into strips, so that the calendering times and calendering ratio are consistent each time the sample is prepared, and finally round noodles are prepared;

[0013] S43: Pre-cooking: Spread the cut noodles evenly and pre-cook them in boiling water for 45 seconds;

[0014] S44: Frying: Take out the pre-cooked noodles, add cooking oil, stir evenly while cooling with cold air, and cool for 10 minutes.

[0015] Furthermore, the method further comprises the following steps:

[0016] S5: Storage: Place the fresh wet alkaline noodles that have been cooled and soaked with oil into a heat-sealed bag, seal it and store it for later use.

[0017] Furthermore, the contents of the above raw materials in parts by weight are: 65-75 parts of flour, 18-25 parts of purified water, 0.2-0.6 parts of edible alkali, 0.01-0.02 parts of ε-polylysine hydrochloride, 0.15-0.25 parts of sucrose ester, and 5-9 parts of edible oil.

[0018] Furthermore, the contents of the above raw materials in parts by weight are: 71.500 parts of flour, 22.900 parts of purified water, 0.430 parts of edible alkali, 0.0140 parts of ε-polylysine hydrochloride, 0.210 parts of sucrose ester, and 7.000 parts of edible oil based on the total mass of the noodles.

[0019] Furthermore, in step S1, all items used for making noodles are sterilized with alcohol and ultraviolet light before use.

[0020] Furthermore, in step S41, the calendered dough needs to be left to rise at 25±1°C for 15 minutes.

[0021] Furthermore, in step S42, the diameter of the round noodle is 1.5 mm and the length is 150 mm.

[0022] Furthermore, in step S5, the fresh wet alkaline noodles are stored in a 4°C refrigerator.

[0023] Furthermore, the method further comprises the following steps:

[0024] S6: Preparation: Take out the fresh wet alkaline noodles from the refrigerator, put them into a special strainer for cooking noodles, blanch them in boiling water for 5 seconds, and shake them up and down to ensure that the noodles are heated evenly.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention provides a method for prolonging the shelf life of fresh wet alkaline noodles by biological preservation and inhibiting starch retrogradation. The method utilizes the biological preservative ε-polylysine hydrochloride for preservation and freshness preservation. The method has certain safety and does not affect the original flavor of the fresh wet alkaline noodles. The method can also inhibit the growth and reproduction of microorganisms and prolong the shelf life of the fresh wet alkaline noodles.

[0027] (2) The present invention provides a method for prolonging the shelf life of fresh wet alkaline noodles and inhibiting starch retrogradation, using sucrose ester to inhibit starch retrogradation during storage of fresh wet alkaline noodles, effectively slowing down the increase in hardness and rough taste caused by starch retrogradation, thereby improving the edible quality of noodles. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0029] Figure 1 It is a diagram of the method steps of the present invention;

[0030] Figure 2 is a method step diagram of step S4 in the present invention;

[0031] Figure 3 It is the sensory scoring results and storage appearance of ordinary wet alkaline noodles;

[0032] Figure 4 It is the sensory evaluation results and storage appearance pictures of fresh wet alkaline noodles containing ε-polylysine hydrochloride;

[0033] Figure 5 It is a schematic diagram of the change in chromaticity of ordinary wet alkaline noodles and fresh wet alkaline noodles containing ε-polylysine hydrochloride during storage;

[0034] Figure 6 It is a schematic diagram of the change of pH value of ordinary wet alkaline noodles and fresh wet alkaline noodles containing ε-polylysine hydrochloride during storage;

[0035] Figure 7 It is a schematic diagram of the change of water content of ordinary wet alkaline noodles and fresh wet alkaline noodles containing ε-polylysine hydrochloride during storage;

[0036] Figure 8 It is a schematic diagram of the water distribution state of ordinary wet alkaline noodles and fresh wet alkaline noodles containing sucrose ester during storage;

[0037] Fig. 9 It is the thermodynamic curve of ordinary wet alkaline noodles and fresh wet alkaline noodles containing sucrose ester during storage;

[0038] Fig.10 It is a schematic diagram of the changes in the crystallization characteristics of ordinary wet alkaline noodles and fresh wet alkaline noodles containing sucrose ester during storage;

[0039] Fig.11 It is a schematic diagram of the microstructure of ordinary wet alkaline noodles and fresh wet alkaline noodles containing sucrose ester during storage. DETAILED DESCRIPTION

[0040] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0041] Example 1

[0042] In this embodiment, the method provided by the present invention is used to prepare fresh wet alkaline noodles with a long shelf life. The mass of flour is 100g as a standard, and the amount of raw materials used is: 100g flour, 32g purified water, 0.6g edible alkali, 0.02g ε-polylysine hydrochloride, and 7g edible oil.

[0043] The specific method is as follows:

[0044] Step 1: Use ultraviolet sterilization and alcohol disinfection to ensure that the noodle making environment is clean and tidy;

[0045] Step 2: Dissolve ε-polylysine hydrochloride and edible alkali in water respectively, and stir well to make dough water;

[0046] Step 3: Slowly pour the dough water into the flour three times, and use a dough mixer to knead the dough for 10 minutes until the dough is loose and flocculent;

[0047] Step 4: Roll the dough once or twice to make it easier to rise;

[0048] Step 5: Place the rolled dough in a temperature of 25±1℃ to rise for 15 minutes to ensure that the gluten and starch in the dough are fully hydrated;

[0049] Step 6: Roll out and cut the noodles into strips, so that the rolling times and rolling ratio are consistent each time, and finally obtain round noodles with a diameter of about 1.5 mm and a length of about 15 cm;

[0050] Step 7: Spread the cut noodles evenly and pre-cook them in boiling water for 45 seconds;

[0051] Step 8: Take out the pre-cooked noodles, add 5% edible oil (based on the total weight of the noodles), stir evenly while cooling with cold air, and cool for 10 minutes;

[0052] Step 9: Place the fresh wet alkaline noodles that have been cooled and soaked in oil into a heat-sealed bag, seal it and store it in a refrigerator at 4°C for later use;

[0053] Step 10: Put the fresh wet alkaline noodles into a special strainer for cooking noodles, blanch them in boiling water for 5 seconds, and shake them up and down to ensure that the noodles are heated evenly.

[0054] Example 2

[0055] This embodiment adopts the same process steps as in Example 1, taking 100g of flour as a standard, wherein the raw materials used are: 100g of flour, 32g of purified water, 0.6g of edible alkali, and 7g of edible oil. However, unlike Example 1, Example 2 is used as a comparative example, and no ε-polylysine hydrochloride is added to obtain ordinary wet alkaline noodles.

[0056] Example 3

[0057] This example is the measurement results of the number of microorganisms in the alkaline noodles prepared in Example 1 and Example 2 during the storage process.

[0058] Table 1 Changes in the number of microorganisms in ordinary wet alkaline noodles during storage

[0059]

[0060] Note: “<1” means 10 -1 No microorganisms were detected in the culture medium.

[0061] Table 2 Changes in the number of microorganisms in fresh wet alkaline noodles containing ε-polylysine hydrochloride during storage

[0062]

[0063] Note: “<1” means 10 -1 No microorganisms were detected in the culture medium.

[0064] The test results show that with the extension of storage time, the total number of colonies and the number of molds and yeasts show an upward trend. It can be seen from Table 1 that the ordinary wet alkaline noodles have exceeded the limit standard at the 7th day, while the number of microorganisms at the 6th day of storage is within the limit standard. Compared with Example 2, it can be seen from Table 2 that ε-polylysine hydrochloride has a significant antibacterial effect, and the number of microorganisms at the 7th day is significantly lower than that of the blank group, and the number of microorganisms after storage for 11 days does not exceed the limit standard.

[0065] Example 4

[0066] This example is used to evaluate the sensory quality of the fresh wet alkaline noodles prepared in Example 1 and record its storage appearance picture.

[0067] The sensory evaluation panel for alkaline noodles consists of 10 people who have received professional sensory evaluation training. The scoring criteria used for sensory evaluation are as follows:

[0068] Table 3 Sensory scoring standards for fresh wet alkaline noodles

[0069]

[0070] Note: The total score is 100 points, and a score below 50 is considered a failure.

[0071] See also Figure 3 , the picture shows the sensory evaluation results and storage appearance of ordinary wet alkaline noodles.

[0072] See also Figure 4 The picture shows the sensory evaluation results and storage appearance of fresh wet alkaline noodles containing ε-polylysine hydrochloride

[0073] The test results showed that the fresh wet alkaline noodles had visible plaques on the 7th day, and sensory evaluation could no longer be performed. However, the sensory score after 6 days of storage was within the acceptable range. It was comprehensively determined that the shelf life of the fresh wet alkaline noodles at 4°C was 6 days. The addition of ε-polylysine hydrochloride had little effect on the sensory quality of the fresh wet alkaline noodles, and the sensory score decreased slowly in the early stage of storage. Deterioration occurred in the later stage of storage. On the 11th day, the total number of microorganisms did not exceed the limit standard, and no mold spots appeared, but the noodles had an odor, and the sensory score was lower than the overall acceptability (50 points). It was comprehensively determined that the addition of ε-polylysine hydrochloride extended the shelf life of the fresh wet alkaline noodles to 10 days.

[0074] Example 5

[0075] See also Figure 5 This example tests the change in chromaticity during storage of the wet alkaline noodles prepared in Example 1 and Example 2. In the figure, the column with hatching is the result of fresh wet alkaline noodles containing ε-polylysine hydrochloride, and the blank column is ordinary wet alkaline noodles.

[0076] The test results show that during the storage at 4°C, the L*, a*, and b* values ​​of the ordinary wet alkaline noodles in Example 2 all have a downward trend, and the decline is relatively slow in the later stage. In addition to the occurrence of browning, the large-scale reproduction of microorganisms will also secrete pigments or metabolites, thereby affecting the color of the noodles. Compared with Example 2, in Example 1, the chromaticity value change trend of the fresh wet alkaline noodles containing ε-polylysine hydrochloride is the same, but the rate of decrease is slow, indicating that the use of biological preservatives inhibits the growth activity of microorganisms and can reduce the rate of color deterioration of noodles during storage.

[0077] Example 6

[0078] See also Figure 6 This example tests the change in pH value during the storage of wet alkaline noodles prepared in Example 1 and Example 2. The blank in the figure represents the measurement result of ordinary wet alkaline noodles.

[0079] The test results show that in Example 2, the pH value of ordinary wet alkaline noodles generally shows a downward trend. In the early stage of storage, the pH value of fresh wet alkaline noodles decreases slightly, but as the storage time increases, the pH value decreases rapidly due to the accelerated growth rate and large-scale reproduction of microorganisms. Compared with the control group of Example 2, in Example 1, the addition of ε-polylysine hydrochloride significantly slows down the downward trend of the pH value of fresh wet alkaline noodles, and the reduction rate of pH value when reaching the shelf life is 2.58%, which is much lower than the decrease of the blank group (4.29%).

[0080] Example 7

[0081] See also Figure 7 This example tests the change in moisture content during storage of fresh wet alkaline noodles prepared in Example 1 and Example 2. In the figure, the column with hatching is the result of fresh wet alkaline noodles containing ε-polylysine hydrochloride, and the blank column is ordinary wet alkaline noodles.

[0082] The test results show that the moisture content of ordinary wet alkaline noodles is generally decreasing, and ε-polylysine hydrochloride can slow down the loss rate of moisture content during the storage of fresh wet alkaline noodles. The moisture content of ordinary wet alkaline noodles decreased by 2.79% on the 6th day. Under the same storage time, the addition of ε-polylysine salt reduced the moisture content of noodles by only 1.63%, indicating that it inhibited the growth and reproduction of microorganisms, thereby reducing the loss of moisture in noodles.

[0083] Example 8

[0084] This example tests the changes in the cooking characteristics of the wet alkaline noodles prepared in Example 1 and Example 2 during storage, and the blank is the result of Example 2. The test results are as follows:

[0085] Table 4 Changes in cooking characteristics of fresh wet alkaline noodles during storage

[0086]

[0087] Note: “Blank” means the spoilage sample was not tested.

[0088] The test results show that with the increase of storage time, the cooking water absorption rate of ordinary wet alkaline noodles decreases, and the loss rate increases. The growth and reproduction of a large number of microorganisms utilize the starch and protein inside the noodles and destroy the gluten network structure, resulting in a decrease in noodle quality. In the table, the cooking loss rate of the blank group of ordinary wet alkaline noodles at the end of the shelf life is 20.81% higher than that at 0d. However, the loss rate of ε-polylysine hydrochloride at the end of the shelf life only increased by 12.63%. It can be seen that it inhibits the growth activity of microorganisms, reduces the damage to the internal structure of noodles, and further reduces the increase in the cooking loss rate of fresh wet alkaline noodles.

[0089] Example 9

[0090] This example tests the changes in texture characteristics of wet alkaline noodles prepared in Example 1 and Example 2 during storage, and the blank is the result of Example 2. The test results are as follows:

[0091] Table 5 Changes in texture characteristics of fresh wet alkaline noodles during storage

[0092]

[0093] Note: “Blank” means the spoilage sample was not tested.

[0094] The test results show that the hardness and cohesion of ordinary wet alkaline noodles increase first and then decrease with the extension of storage time. Among them, the hardness of noodles containing ε-polylysine hydrochloride does not decrease in the later stage, but the growth trend decreases. The texture characteristics of the sample containing ε-polylysine hydrochloride are slightly better than those of the blank group in the same period, indicating that it inhibits the growth and reproduction of microorganisms, thereby delaying the decomposition of starch and protein and improving the texture quality of noodles.

[0095] Example 10

[0096] This example tests the changes in sensory quality during the storage of wet alkaline noodles prepared in Examples 1 and 2, with the blank being the result of Example 2. The scoring criteria used for the sensory evaluation are the same as those in Table 3.

[0097] The test results are shown in the following table:

[0098] Table 6 Changes in sensory quality of fresh wet alkaline noodles during storage

[0099]

[0100]

[0101] Note: “Blank” means the spoilage sample was not tested.

[0102] The test results show that the appearance, color and taste of the freshly prepared ordinary wet alkaline noodles are good, indicating that the addition of ε-polylysine hydrochloride does not affect the initial sensory quality of the noodles. As the storage time increases, the scores of indicators such as color, taste and flavor of the cooked noodles show a downward trend, which is mainly affected by the consumption of starch and protein in the noodles by microorganisms, further leading to a decline in sensory quality. Among them, ε-polylysine hydrochloride has a good effect on maintaining odor and taste, delaying the decline in sensory quality, which is related to its good inhibitory effect on microorganisms.

[0103] Embodiment 11

[0104] This embodiment adopts the method provided by the present invention to prepare fresh wet alkaline noodles with a long shelf life and suppressed starch retrogradation, which is different from Example 1 in that sucrose ester is added to the flour. The mass of flour is 100g as a standard, and the amount of raw materials used is: 100g flour, 32g purified water, 0.6g edible alkali, 0.02g ε-polylysine hydrochloride, 0.3g sucrose ester, and 7g edible oil.

[0105] The specific method is as follows:

[0106] Step 1: Use ultraviolet sterilization and alcohol disinfection to ensure that the noodle making environment is clean and tidy;

[0107] Step 2: dissolving ε-polylysine hydrochloride and edible alkali in water respectively, stirring well to make dough water, and mixing sucrose ester and flour evenly;

[0108] Step 3: Slowly pour the dough water into the flour three times, and use a dough mixer to knead the dough for 10 minutes until the dough is loose and flocculent;

[0109] Step 4: Roll the dough once or twice to make it easier to rise;

[0110] Step 5: Place the rolled dough in a temperature of 25±1℃ to rise for 15 minutes to ensure that the gluten and starch in the dough are fully hydrated;

[0111] Step 6: Roll out and cut the noodles into strips, so that the rolling times and rolling ratio are consistent each time, and finally obtain round noodles with a diameter of about 1.5 mm and a length of about 15 cm;

[0112] Step 7: Spread the cut noodles evenly and pre-cook them in boiling water for 45 seconds;

[0113] Step 8: Take out the pre-cooked noodles, add 5% edible oil (based on the total weight of the noodles), stir evenly while cooling with cold air, and cool for 10 minutes;

[0114] Step 9: Place the fresh wet alkaline noodles that have been cooled and soaked in oil into a heat-sealed bag, seal it and store it in a refrigerator at 4°C for later use;

[0115] Step 10: Put the fresh wet alkaline noodles into a special strainer for cooking noodles, blanch them in boiling water for 5 seconds, and shake them up and down to ensure that the noodles are heated evenly.

[0116] Example 12

[0117] This example tests the texture characteristics of the wet alkaline noodles prepared in Example 2 and Example 11 during storage. The test results are shown in the following table:

[0118] Table 7 Texture characteristics of fresh wet alkaline noodles during storage

[0119]

[0120] The test results show that the hardness, shear stress and work done of fresh wet alkali noodles increase with the extension of storage time, while the elasticity, breaking force and breaking distance show a downward trend. The texture characteristics of fresh wet alkali noodles are significantly improved with the addition of sucrose esters. After 10 days of storage, the hardness growth rate of fresh wet alkali noodles containing sucrose esters is 13.55%, which is significantly lower than 52.80% of ordinary wet alkali noodles. It significantly delays the increase of hardness of fresh wet alkali noodles and maintains good elasticity, which is related to its delayed starch recovery.

[0121] Embodiment 13

[0122] This example is used to evaluate the sensory quality of the wet alkaline noodles prepared in Example 2 and Example 2 during storage. The sensory evaluation panel is the same as that in Example 3, and the scoring criteria used for the sensory evaluation are as follows:

[0123] Table 8 Sensory scoring standards for fresh wet alkaline noodles

[0124]

[0125] The sensory evaluation results are shown in the following table:

[0126] Table 9 Sensory evaluation results during storage of fresh wet alkaline noodles

[0127]

[0128] Table 10 Moisture distribution during storage of fresh wet alkaline noodles

[0129]

[0130] The test results show that the addition of sucrose esters has no significant effect on the color of fresh wet alkaline noodles, but improves the taste such as elasticity, hardness and smoothness. As the storage time increases, the elasticity of the noodles begins to decrease, the hardness increases, and a powdery feeling with an unsmooth taste appears. The fresh wet alkaline noodles undergo retrogradation, resulting in a decline in edible quality. The addition of sucrose esters delays the decline in sensory quality, has a good improvement effect on the hardness and smoothness of the noodles, and the total sensory score is significantly higher than that of the blank group, delaying the occurrence of starch retrogradation in fresh wet alkaline noodles.

[0131] Embodiment 14

[0132] See also Figure 8 This example tests the moisture distribution of wet alkaline noodles prepared in Example 2 and Example 11 during storage. The test results show that:

[0133] After adding sucrose ester, the T2 relaxation time of fresh wet alkaline noodles is shorter than that of the control group in Example 2, indicating that its addition can inhibit water mobility and enhance the water holding capacity of noodles. It can be found from the figure that P22>P21>P23, indicating that the water content of T22 is dominant, the water content that is not easy to flow in the noodles is the highest, and the free water content is the lowest. With the extension of storage time, the water content proportions P22 and P23 show an increasing trend, while P21 gradually decreases, indicating that the bound water in the noodles migrates to the water that is not easy to flow and the free water. After storage for 10 days, the sample containing sucrose ester reduces the proportion of free water compared to the ordinary wet alkaline noodle control group, further indicating that sucrose ester increases the binding of water to the system, adjusts the water distribution state of fresh wet alkaline noodles, and delays the recovery rate.

[0134] Embodiment 15

[0135] This example tests the thermodynamic properties of the wet alkaline noodles prepared in Example 2 and Example 11 during storage. The test results are as follows: Fig. 9 And Table 11:

[0136] Table 11 Changes in thermodynamic parameters during storage of fresh wet alkaline noodles

[0137]

[0138] The test results show that, see Fig. 9 , an endothermic peak appeared in DSC, indicating that the noodles had undergone retrogradation. The endothermic peak appeared at about 50°C, which was related to the melting of the amylopectin crystal peak, indicating that the long-term retrogradation of starch caused by amylopectin recrystallization was the dominant factor in the retrogradation of fresh wet alkaline noodles. After being placed under refrigerated conditions at 4°C, the area of ​​the endothermic peak increased with the increase in storage days, and the thermal enthalpy value increased, indicating that the degree of retrogradation of noodles deepened. As shown in Table 11, the addition of sucrose ester reduced the retrogradation enthalpy value of fresh wet alkaline noodles and reduced the area of ​​the endothermic peak, indicating that it can effectively inhibit the recrystallization of starch during the refrigeration process, thereby delaying the process of starch retrogradation in noodles.

[0139] Example 16

[0140] See also Fig.10 This example tests the crystallization characteristics of wet alkali noodles prepared in Example 2 and Example 11 during storage. The test results show that compared with the ordinary wet alkali noodles prepared in Example 2, no new crystals are generated in the composite system, indicating that the addition of sucrose ester has no effect on the type of starch crystallization. As can be seen from the figure, the crystallization spectrum at 0d is mainly distributed near 20°, which is a V-type crystallization peak. After being stored at 4°C for 10d, it can be found that the fresh wet alkali noodles have obvious crystallization peaks at 17° and 20°, showing B+V-type crystallization. Compared with the peak intensity near 17° at 0d, it is a B-type crystallization peak, which is mainly caused by starch recrystallization. This result verifies that starch retrogradation has occurred in the fresh wet alkali noodles.

[0141] As time goes by, the crystallinity of starch increases. The relative crystallinity of the control group increases from 2.39% to 3.83%. The diffraction peak intensity near 17° in the sucrose ester sample is weaker and the crystallinity is smaller. The crystallinity after storage for 10 days is 2.97%, indicating that it can inhibit the recrystallization of starch and delay the regeneration of fresh wet alkaline noodles.

[0142] Embodiment 17

[0143] See also Fig.11 In this example, the microstructure of wet alkaline noodles prepared in Example 2 and Example 11 was tested. The test results showed that since the fresh wet alkaline noodles were subjected to the oil mixing and oil infiltration cooling process, the internal structure of the noodle samples at 0d was wrapped in oil and presented a smooth surface. Holes appeared in the network structure of the blank sample, which may be caused by the short-term regeneration of the fresh wet alkaline noodles during the oil mixing and cooling process, resulting in the crystallization of amylose; while the noodle structure of sucrose ester was relatively compact, which was speculated to be due to the combination of sucrose ester and amylose, thereby inhibiting the occurrence of short-term regeneration. After refrigeration for 10d, the internal network structure of the noodles became incomplete, which may be caused by refrigeration and starch recrystallization. Compared with the ordinary wet alkaline noodles in Example 2, the fresh wet alkaline noodles containing sucrose ester had a more continuous structure and fewer holes, indicating that its addition effectively inhibited the degree of starch crystallization and delayed starch regeneration.

[0144] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed in the present invention should be covered by the present invention.

Claims

1. A biological preservation method for extending the shelf life of fresh wet alkaline noodles and inhibiting starch retrogradation, characterized in that: The following steps are involved: S1: Disinfection: Sterilize and disinfect the noodle making environment to ensure that the noodle making environment is clean and tidy; S2: Ingredients: dissolve ε-polylysine hydrochloride and edible alkali in water respectively, stir well to make dough water, and mix sucrose ester and flour evenly; S3: Kneading dough: slowly pour the kneading water containing ε-polylysine hydrochloride into the flour containing sucrose ester several times, and knead the dough with a dough mixer until the dough is loose and flocculent; S4: Noodle making: making the dough into noodles.

2. A biological preservation method for extending the shelf life of fresh wet alkaline noodles and inhibiting starch retrogradation according to claim 1, characterized in that: The S4 step also includes the following sub-steps: S41: Proofing: Compound-calender the dough for one or two times, and place the rolled dough at a suitable temperature for a set time to ensure that the gluten and starch in the dough are fully hydrated; S42: calendering: calendering and cutting the noodle floss into strips, so that the calendering times and calendering ratio are consistent each time the sample is prepared, and finally round noodles are prepared; S43: Pre-cooking: Spread the cut noodles evenly and pre-cook them in boiling water for 45 seconds; S44: Frying: Take out the pre-cooked noodles, add cooking oil, stir evenly while cooling with cold air, and cool for 10 minutes.

3. A biological preservation method for extending the shelf life of fresh wet alkaline noodles and inhibiting starch retrogradation according to claim 2, characterized in that: The following steps are also included: S5: Storage: Place the fresh wet alkaline noodles that have been cooled and soaked with oil into a heat-sealed bag, seal it and store it for later use.

4. A biological preservation method for extending the shelf life of fresh wet alkaline noodles and inhibiting starch retrogradation according to claim 2 or 3, characterized in that: The contents of the above raw materials in parts by weight are: 65-75 parts of flour, 18-25 parts of purified water, 0.2-0.6 parts of edible alkali, 0.01-0.02 parts of ε-polylysine hydrochloride, 0.15-0.25 parts of sucrose ester, and 5-9 parts of edible oil.

5. A biological preservation method for extending the shelf life of fresh wet alkaline noodles and inhibiting starch retrogradation according to claim 4, characterized in that: The contents of the above raw materials in parts by weight are: 71.500 parts of flour, 22.900 parts of purified water, 0.430 parts of edible alkali, 0.0140 parts of ε-polylysine hydrochloride, 0.210 parts of sucrose ester, and 7.000 parts of edible oil based on the total weight of the noodles.

6. The method for prolonging the shelf life of fresh wet alkaline noodles and inhibiting starch retrogradation according to claim 1, characterized in that: In step S1, all items used for noodle making are disinfected with alcohol and sterilized with ultraviolet light before use.

7. The method for prolonging the shelf life of fresh wet alkaline noodles and inhibiting starch retrogradation according to claim 1, characterized in that: In step S41, the calendered dough needs to be left to rise at 25±1°C for 15 minutes.

8. The method for prolonging the shelf life of fresh wet alkaline noodles and inhibiting starch retrogradation according to claim 1, characterized in that: In step S42, the diameter of the round noodle is 1.5 mm and the length is 150 mm.

9. The method for prolonging the shelf life of fresh wet alkaline noodles and inhibiting starch retrogradation according to claim 3, characterized in that: In step S5, the fresh wet alkaline noodles are stored in a 4°C refrigerator.

10. A biological preservation method for extending the shelf life of fresh wet alkaline noodles and inhibiting starch retrogradation according to claim 9, characterized in that: The following steps are also included: S6: Preparation: Take out the fresh wet alkaline noodles from the refrigerator, put them into a special strainer for cooking noodles, blanch them in boiling water for 5 seconds, and shake them up and down to ensure that the noodles are heated evenly.

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