Modified acorn starch loaded with plant essential oil and method for prolonging shelf life of cooked wheaten food

Abstract

The invention discloses a method for prolonging the shelf life of cooked wheaten food at normal temperature. The method comprises the following steps: S1, preparing OSA modified acorn starch; s2, carrying out enzymolysis on the OSA modified acorn starch; s3, preparing a plant essential oil emulsion; s4, loading the plant essential oil emulsion on the acorn starch; and S5, preparing the antibacterial bag. Holes are formed in the surfaces and interiors of the starch particles. The pores enable the starch particles to become loose and porous, and the specific surface area is increased, so that the physicochemical properties and functional characteristics of the starch are changed. The formation of the porous starch not only improves the adsorption performance of the starch, but also enhances the solubility and expansibility of the starch. Due to the porous structure, water molecules can more easily permeate into starch particles, dissolution and expansion of starch are promoted, essential oil can more easily enter the starch, and the loading rate of the essential oil is increased. And in a dry environment, the essential oil can also be slowly released from the porous starch structure.

Description

Technical Field

[0001] The invention relates to the technical field of food preservation, and in particular to a method for prolonging the shelf life of pasta at room temperature. Background Art

[0002] The common preservation method for pasta is low temperature refrigeration or freezing. Although it can extend the shelf life of pasta to a certain extent, the preservation methods of low temperature freezing and refrigeration make the taste of pasta worse and need to be heated before eating. Therefore, the key point of room temperature preservation of pasta is to develop a preservation technology that can extend the shelf life of pasta at room temperature and reduce the impact on the flavor of pasta. Summary of the invention

[0003] In view of the shortcomings of the existing technology in solving the preservation problem, the present invention provides a method for extending the shelf life of pasta at room temperature, a method for modifying acorn starch by a chemical method combined with an enzymatic method to load a plant essential oil antibacterial emulsion and make a portable fresh-keeping package that can be directly used for pasta preservation, which has high safety, good antibacterial effect and low cost.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is: A method for extending the shelf life of pasta, comprising the following steps: S1 preparation of OSA-modified acorn starch; S2 enzymatically hydrolyzed OSA-modified acorn starch; S3 prepares plant essential oil emulsion; S4 acorn starch loaded with plant essential oil emulsion; Preparation of S5 antibacterial package.

[0005] Furthermore, OSA-modified acorn starch is prepared by mixing acorn starch with water to form a starch aqueous solution, then homogenizing to achieve a uniform and stable state, adjusting the pH to alkaline, adding OSA solution, and adjusting the pH of the solution to neutral or weakly acidic after the reaction is completed, then washing, drying, sieving, sealing and storing in a drying dish.

[0006] Further, neutral or weakly acidic is pH 5-6.8; Further, the alkalinity is 8-11.5; Furthermore, the reaction temperature is 20-60°C; and the reaction time is 1-10h.

[0007] Furthermore, enzymatic hydrolysis of OSA-modified acorn starch: water is added to the modified acorn starch after OSA esterification to prepare a starch suspension, thereby preparing a uniform and stable starch solution; then an enzyme solution prepared from glucoamylase, α-amylase and pullulanase is added to perform enzymatic hydrolysis; after the enzymatic hydrolysis is completed, the precipitate is separated from the supernatant, and the precipitate is washed, dried and sieved to obtain enzymatically modified acorn porous starch.

[0008] Furthermore, the ratio of the enzyme solution prepared by glucoamylase, α-amylase and pullulanase is (1-8):(0.6-5):(0.5-4), preferably 2:1.5:1.

[0009] Furthermore, the enzymolysis temperature is 40-50°C, and the enzymolysis time is 6-18h; preferably, the enzymolysis temperature is 45°C, and the enzymolysis time is 12h.

[0010] Furthermore, the plant essential oil emulsion is prepared by selecting plant raw materials, using edible ethanol as a solvent, adding an emulsifier, and then performing ultrasonic emulsification to prepare a uniform and stable essential oil emulsion.

[0011] Furthermore, the plant raw material is preferably a combination of one or more of oregano, cinnamon, and thyme; further, a combination of oregano, cinnamon, and thyme; further, oregano: cinnamon: thyme = 1.5:1.2:1.

[0012] Furthermore, a mixed plant essential oil emulsion is prepared by mixing the enzymatically hydrolyzed OSA-modified acorn starch and the plant essential oil emulsion.

[0013] Preferably, centrifugal mixing is performed; specifically, centrifugation is performed in a centrifuge, and the centrifugation operation is repeated several times to allow the essential oil to be fully filled into the modified porous starch, and the excess plant essential oil emulsion is filtered and removed, and the mixture is dried in an oven and placed in a sealed bag for later use. This also helps the essential oil to enter the starch more easily, thereby increasing the loading rate of the essential oil. In a dry environment, the essential oil can also be slowly released from the porous starch structure.

[0014] Furthermore, the production of antibacterial packages: acorn starch loaded with plant essential oil emulsion is made into a small antibacterial package using food-grade non-woven packaging materials and placed in pasta packaging. Plant essential oils can be slowly released from starch to achieve a better antibacterial effect, directly contacting the sealed packaging of pasta. Essential oils containing antibacterial ingredients are slowly released in the packaging, which can directly extend the shelf life of pasta at room temperature, achieving the effect of keeping pasta fresh at room temperature.

[0015] Furthermore, the pasta is preferably steamed bread.

[0016] The present invention provides an enzymatic OSA-modified acorn starch loaded with a plant essential oil emulsion, and the preparation method comprises: S1 preparation of OSA-modified acorn starch; S2 enzymatically hydrolyzed OSA-modified acorn starch; S3 prepares plant essential oil emulsion; S4 acorn starch loaded with plant essential oil emulsion.

[0017] Furthermore, OSA-modified acorn starch is prepared by mixing acorn starch with water to form a starch aqueous solution, then homogenizing to achieve a uniform and stable state, adjusting the pH to alkaline, adding OSA solution, and adjusting the pH of the solution to neutral or weakly acidic after the reaction is completed, then washing, drying, sieving, sealing and storing in a drying dish.

[0018] Further, neutral or weakly acidic is pH 5-6.8; Further, the alkalinity is 8-11.5; Furthermore, the reaction temperature is 20-60°C; and the reaction time is 1-10h.

[0019] Furthermore, enzymatic hydrolysis of OSA-modified acorn starch: water is added to the modified acorn starch after OSA esterification to prepare a starch suspension, thereby preparing a uniform and stable starch solution; then an enzyme solution prepared from glucoamylase, α-amylase and pullulanase is added to perform enzymatic hydrolysis; after the enzymatic hydrolysis is completed, the precipitate is separated from the supernatant, and the precipitate is washed, dried and sieved to obtain enzymatically modified acorn porous starch.

[0020] Furthermore, the ratio of the enzyme solution prepared by glucoamylase, α-amylase and pullulanase is (1-8):(0.6-5):(0.5-4), preferably 2:1.5:1.

[0021] Furthermore, the enzymolysis temperature is 40-50°C, and the enzymolysis time is 6-18h; preferably, the enzymolysis temperature is 45°C, and the enzymolysis time is 12h.

[0022] Furthermore, the plant essential oil emulsion is prepared by selecting plant raw materials, using edible ethanol as a solvent, adding an emulsifier, and then performing ultrasonic emulsification to prepare a uniform and stable essential oil emulsion.

[0023] Furthermore, the plant raw material is preferably a combination of one or more of oregano, cinnamon, and thyme; further, a combination of oregano, cinnamon, and thyme; further, oregano: cinnamon: thyme = 1.5:1.2:1.

[0024] Furthermore, a mixed plant essential oil emulsion is prepared by mixing the enzymatically hydrolyzed OSA-modified acorn starch and the plant essential oil emulsion.

[0025] Preferably, centrifugal mixing is performed; specifically, centrifugation is performed in a centrifuge, and the centrifugation operation is repeated several times to allow the essential oil to be fully filled into the modified porous starch, and the excess plant essential oil emulsion is filtered and removed, and the mixture is dried in an oven and placed in a sealed bag for later use. This also helps the essential oil to enter the starch more easily, thereby increasing the loading rate of the essential oil. In a dry environment, the essential oil can also be slowly released from the porous starch structure.

[0026] Furthermore, the ratio of acorn starch to distilled water is 30% to 40%, the speed of the homogenizer is in the range of 2500 to 5000 RPM, the temperature is in the range of 50 to 60°C, the pressure is in the range of 6 to 8 MPa, and the homogenization time is 10 to 15 min. The reaction temperature of the esterification reaction is 45~50℃, and the reaction time is 3~5h. After the reaction is completed, the pH of the solution is adjusted to 6.5 with HCL, and then washed three times with anhydrous ethanol and distilled water respectively, dried in an oven at 110℃ for 2h, passed through a 100-mesh sieve, and sealed and stored in a drying dish.

[0027] The beneficial effects of the present invention are as follows: the present invention first esterifies acorn starch with OSA, and when octenyl succinic anhydride and starch undergo an esterification reaction, the anhydride ring is opened, one end of which is combined with the carboxyl group of the starch molecule by an ester bond, and the other end produces a carboxylic acid. This reaction increases the hydrophilic and hydrophobic groups of the starch molecule, so that the modified starch has amphiphilic properties. The esterification reaction may reduce the thermal stability of starch, which is manifested as a decrease in the initial temperature of thermal degradation. This may be due to the introduction of OSA changing the internal structure of the starch molecule, making it more susceptible to degradation at high temperatures. Since OSA-modified starch has amphiphilic properties, its emulsification ability and emulsification stability are usually improved. Then the acorn starch esterified with OSA is conducive to the next step of modification with a composite enzyme solution, and then enzymatically hydrolyzed by three enzyme solutions. The composite enzyme solution acts on the non-crystalline region of the starch granules, decomposes the starch molecules into smaller fragments through hydrolysis, and forms holes on the surface and inside of the starch granules. These holes make the starch granules loose and porous, increase the specific surface area, and thus change the physical and chemical properties and functional properties of the starch. The formation of porous starch not only improves the adsorption performance of starch, but also enhances its solubility and swelling power. The porous structure makes it easier for water molecules to penetrate into the starch granules, promotes the dissolution and swelling of starch, makes it easier for essential oils to enter the starch, and increases the loading rate of essential oils. In a dry environment, essential oils can also be slowly released from the porous starch structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the product picture of Example 1 after being left for 15 days; Figure 2 This is the product picture of comparative example 1 after being placed for 15 days; Figure 3 This is the product picture of comparative example 2 after being placed for 15 days; Figure 4 This is the product picture of comparative example 3 after being placed for 15 days; Figure 5 This is the product picture of comparative example 4 after being placed for 15 days; Figure 6 Place 15 days of product images for blank reconciliation group. DETAILED DESCRIPTION

[0029] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments, and the contents mentioned in the implementation modes are not intended to limit the present invention. Example 1

[0030] A method for extending the shelf life of pasta at room temperature comprises the following steps: S1 preparation of OSA-modified acorn starch; S2 enzymatically hydrolyzed OSA-modified acorn starch; S3 prepares plant essential oil emulsion; S4 acorn starch loaded with plant essential oil emulsion; Preparation of S5 antibacterial package.

[0031] Acorn starch and distilled water are mixed in a certain ratio to form a starch emulsion, which is then homogenized in a homogenizer to a relatively uniform and stable state. The homogenized acorn starch aqueous solution is stirred in a magnetic stirrer, and then the OSA ethanol solution is slowly added to the solution to complete the esterification reaction. Enzymatic hydrolysis of OSA-modified acorn starch: Add 3 times the volume of deionized water to the acorn starch that has completed the esterification reaction to prepare a starch suspension, and add the mixed enzyme solution under stirring with a magnetic stirrer to complete the enzymatic hydrolysis process.

[0032] Preparation of mixed plant essential oil emulsion: the types of plant essential oil emulsions used include oregano, cinnamon, and thyme. Edible ethanol is used as a solvent, an emulsifier is added, and then ultrasonic emulsification is performed to prepare a uniform and stable essential oil emulsion.

[0033] Acorn starch loaded with plant essential oil emulsion: acorn starch and mixed plant essential oil emulsion are centrifuged in a centrifuge, and the centrifugation operation is repeated three times to allow the essential oil to be fully filled into the modified porous starch, and the excess plant essential oil emulsion is filtered and removed, and the mixture is dried in an oven and placed in a sealed bag for later use.

[0034] Preparation of antibacterial bags: Acorn starch loaded with plant essential oil emulsion is made into small-volume antibacterial bags using food-grade non-woven packaging materials and directly placed in pasta packaging. The plant essential oil can be slowly released from the starch to achieve a better antibacterial effect. It is in direct contact with the sealed packaging of pasta. The essential oil containing antibacterial ingredients is slowly released in the packaging, which can directly extend the shelf life of pasta at room temperature and achieve the effect of keeping pasta fresh at room temperature.

[0035] The ratio of acorn starch to distilled water was 30%, the speed of the homogenizer was in the range of 4000 RPM, the temperature was in the range of 60°C, the pressure was in the range of 8 MPa, and the homogenization time was 10 min.

[0036] The reaction temperature of the esterification reaction is 50°C, and the reaction time is 3h. After the reaction is completed, the pH of the solution is adjusted to 6.5 with HCL, and then washed three times with anhydrous ethanol and distilled water respectively, dried in an oven at 110°C for 2h, passed through a 100-mesh sieve, and sealed and stored in a drying dish.

[0037] The enzymes used in the mixed enzyme solution are mainly glucoamylase, α-amylase and pullulanase. The three are mixed in a certain proportion. The ratio used in this experiment is 2:1.5:1. The solution is transferred to a constant temperature shaker at 45°C for enzymolysis for 12 hours. The reaction is then stopped with 1 mol / L NaOH solution. The supernatant and the precipitate are separated. The precipitate is washed three times with anhydrous ethanol and distilled water respectively, then dried, passed through a 200-mesh sieve, and sealed for storage.

[0038] The compounding ratio of the three plant essential oils is 1.5:1.2:1, and an emulsifier prepared by mixing Tween 80 and Tween-20 is added in a ratio of 1:2. The power used for ultrasound is 100 W, the time is 20 minutes, and the mixture is emulsified at a high speed of 8000 r / min for 180 s.

[0039] Essential oil emulsion of about 3 times the volume of starch was added to the centrifuge tube, and the parameters of the centrifuge were set to centrifuge at 3000 r / min for 15 minutes to obtain modified acorn starch loaded with plant essential oil emulsion.

[0040] The volume of the antibacterial package is changed according to the packaging volume of the pasta. Several general packaging volumes are provided, namely 4×4 CM, the packaging volume of fresh-keeping pasta is 15×10 CM, and 6×6 CM, the packaging volume of fresh-keeping pasta is 25×15 CM.

[0041] Comparative Example 1 The same as Example 1, except that chitosan is used instead of acorn starch.

[0042] Comparative Example 2 Same as Example 1, except that no OSA modification was performed.

[0043] Comparative Example 3 The same as Example 1, except that no enzymatic hydrolysis operation was performed.

[0044] Comparative Example 4 The same as Example 1, except that the acorn starch-loaded plant essential oil emulsion is ground and mixed, and the essential oil is added during the grinding to fuse the essential oil and starch together.

[0045] Using Example 1 and Comparative Examples 1-4 as examples, (1) record the number of days when the essential oil cannot be smelled from the acorn starch loaded with the plant essential oil emulsion, repeat the test 10 times in parallel, and take the average value. (2) 4×4 CM antibacterial package, the packaging volume of the steamed buns that can be kept fresh is 15×10 CM, place the packaged steamed buns at room temperature (25°C), and record the number of days when mold spots appear on the steamed buns. Repeat the test 10 times in parallel, and take the average value (the control group is the one without the antibacterial package). Take photos on the 15th day.

[0046] Table 1 From Table 1, and Figure 1-6 It can be seen that the acorn starch after OSA esterification is conducive to the next step of modification with a complex enzyme solution. The formation of porous starch not only improves the adsorption performance of starch, but also enhances its solubility and swelling power. The porous structure makes it easier for water molecules to penetrate into the starch granules, promotes the dissolution and swelling of starch, makes it easier for essential oils to enter the starch, and increases the loading rate of essential oils. In a dry environment, essential oils can also be slowly released from the porous starch structure, which increases the storage time of steamed bread at room temperature.

[0047] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as herein.

[0048] It should be understood that the detailed description of the technical solutions of the present invention by means of the preferred embodiments is illustrative rather than restrictive. A person skilled in the art may modify the technical solutions described in the embodiments, or replace some of the technical features by equivalents, based on reading the specification of the present invention; and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for extending the shelf life of pasta, characterized in that: The following steps are involved: S1 preparation of OSA-modified acorn starch; S2 enzymatically hydrolyzed OSA-modified acorn starch; S3 prepares plant essential oil emulsion; S4 acorn starch loaded with plant essential oil emulsion; Preparation of S5 antibacterial package.

2. The method according to claim 1, characterized in that Preparation of OSA-modified acorn starch: acorn starch and water are mixed to form a starch aqueous solution, which is then homogenized to achieve a uniform and stable state, the pH is adjusted to alkaline, OSA solution is added, and after the reaction is completed, the pH of the solution is adjusted to neutral or weakly acidic, and then washed, dried, sieved, sealed, and stored in a drying dish.

3. The method according to claim 1, characterized in that Enzymatic hydrolysis of OSA-modified acorn starch: The modified acorn starch after OSA esterification is added with water to prepare a starch suspension, and then a uniform and stable starch solution is prepared. Then, an enzyme solution prepared by glucoamylase, α-amylase and pullulanase is added to perform enzymatic hydrolysis. After the enzymatic hydrolysis is completed, the precipitate is separated from the supernatant, and the precipitate is washed, dried and sieved to obtain enzymatically modified acorn porous starch.

4. The method according to claim 3, characterized in that The enzyme solution prepared by glucoamylase, α-amylase and pullulanase has a ratio of (1-8): (0.6-5): (0.5-4), preferably 2:1.5:1; and / or The enzymolysis temperature is 40-50°C, and the enzymolysis time is 6-18h; preferably, the enzymolysis temperature is 45°C, and the enzymolysis time is 12h.

5. The method according to claim 1, characterized in that Preparation of plant essential oil emulsion: selecting plant raw materials, using edible ethanol as solvent, adding emulsifier, and then performing ultrasonic emulsification to prepare a uniform and stable essential oil emulsion; Furthermore, the plant raw material is preferably a combination of one or more of oregano, cinnamon, and thyme; further, a combination of oregano, cinnamon, and thyme; further, oregano: cinnamon: thyme = 1.5:1.2:

1.

6. The method according to claim 1, characterized in that Preparation of mixed plant essential oil emulsion: Enzymatically hydrolyzed OSA-modified acorn starch and plant essential oil emulsion are centrifugally mixed.

7. The method according to claim 6, characterized in that Centrifuge in a centrifuge and repeat the centrifugation operation several times to allow the essential oil to be fully filled into the modified porous starch.

8. The method according to claim 1, characterized in that Preparation of antibacterial package: acorn starch loaded with plant essential oil emulsion is made into a small antibacterial package with food-grade non-woven packaging material and placed in the pasta packaging. Plant essential oil can be slowly released from the starch to achieve a good antibacterial effect, directly in contact with the sealed packaging of pasta, and the essential oil containing antibacterial ingredients is slowly released in the packaging, which can directly extend the shelf life of pasta at room temperature and achieve the effect of keeping pasta fresh at room temperature.

9. The method according to claim 1, characterized in that The pasta is preferably steamed bread.

10. An enzymatic OSA-modified acorn starch loaded with plant essential oil emulsion, characterized in that: The preparation method comprises: S1 preparation of OSA-modified acorn starch; S2 enzymatically hydrolyzed OSA-modified acorn starch; S3 prepares plant essential oil emulsion; S4 acorn starch loaded with plant essential oil emulsion.

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