Natto active substance, natto-flavored konjac jelly and preparation method of natto active substance and natto-flavored konjac jelly

Abstract

The invention discloses a natto active substance, natto-flavored konjac jelly and a preparation method thereof, and relates to the technical field of food processing. The preparation method of the natto active substance comprises the following steps: mixing mature natto and normal saline according to a volume ratio of (1-1.1): (2-2.2), extracting for 24-26 hours, centrifugally filtering the obtained extract liquid, and reserving supernate to obtain a crude extract liquid; and mixing the crude extract and an ammonium sulfate solution with the saturation degree of 30% according to the volume ratio of (28-32): (12-15), carrying out primary salting-out, then carrying out primary centrifugal filtration, adding an ammonium sulfate saturated solution into the supernatant obtained by the primary salting-out until the saturation degree is 70-72%, carrying out secondary salting-out, then carrying out secondary centrifugal filtration, and taking the precipitate, thereby obtaining the natto active substance. The preparation method is simple, the natto active substance is extracted from the mature natto through extraction and secondary salting-out, the extraction rate is high, the purity is high, the obtained natto active substance is applied to the jelly, the flavor of the jelly can be increased, and the digestibility of the jelly can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, and in particular to a natto active substance, a natto konjac jelly and a preparation method thereof. Background Art

[0002] In recent years, with the rapid development of the fast food industry, there are a wide variety of jelly products on the market. Jelly has attracted a large number of young consumers due to its rich taste and varied flavors. However, due to its processing characteristics, jelly is also difficult to digest, which has aroused the concern of consumers and does not meet the pursuit of healthy diet by contemporary consumers. Natto bacteria in natto can produce nattoin substances (such as nattokinase), which is an alkaline serine protease secreted by natto bacteria to the extracellular space after fermentation. The enzyme not only has obvious thrombolytic activity, but also can activate plasminogen in the body and increase the content of endogenous fibrinolytic enzymes, which can be used to produce health foods. Nattokinase is a protein with extremely small molecular weight. It has the characteristics of rapid action, long maintenance time, food source, good safety performance, etc. It has a small molecular weight and is a single-chain protein. It is easier to be digested and absorbed by the human body. It can be absorbed by the digestive tract and has an effect on fibrin. Nattokinase is a fibrinolytic enzyme that can directly act on fibrin and decompose it. Therefore, it is applied to the production of jelly technology, and the jelly made has a unique flavor and has a good market prospect, and can provide consumers with a healthier and more health-care consumption choice.

[0003] In addition, traditional jelly is made of water and sugar as the main raw materials, supplemented with thickeners and other food additives through processes such as sol, mixing, filling, sterilization, and cooling. Due to its high sterilization temperature, it basically does not undergo fermentation to extract active substances and apply them to the preparation process of jelly production. Summary of the invention

[0004] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a natto active substance, a natto-flavored konjac jelly and a preparation method thereof, which can stably extract the natto active substance contained in the raw material, and the natto active substance of the present invention is applied to the acidic konjac jelly without being easily denatured and inactivated, and its activity can be efficiently maintained during the production process, thereby improving the human body's digestion ability of konjac jelly.

[0005] The present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing a natto active substance, comprising the following steps:

[0007] S1. Mix the mature natto and physiological saline in a volume ratio of (1-1.1): (2-2.2) and extract for 24h-26h, centrifuge and filter the obtained extract, retain the supernatant, and obtain a crude extract;

[0008] S2. The crude extract and a 30% saturated ammonium sulfate solution are mixed in a volume ratio of (28-32): (12-15) to perform a salting out, and then centrifuge once. A saturated ammonium sulfate solution is added to the supernatant of the first salting out to a saturation of 70%-72%, and a second salting out is performed. Then, a second centrifuge is performed to obtain a precipitate to obtain a natto active substance.

[0009] Furthermore, the mass ratio of the supernatant to the saturated ammonium sulfate solution is (35-37): (46-48). Furthermore, the centrifugal speed is 7000-7200 r / min, and the time is 15-20 min.

[0010] Furthermore, the method for preparing the mature natto is as follows: washing the soybeans and then high-pressure steaming them at 121° C. for 40-45 minutes, cooling them to room temperature, adding 30-35 ml of natto bacteria powder for fermentation, and obtaining mature natto.

[0011] Secondly, the present invention also provides a natto active substance prepared by the above-mentioned preparation method of natto active substance.

[0012] In addition, the present invention also provides a natto konjac jelly comprising the natto active substance.

[0013] Finally, the present invention also provides a method for preparing the natto konjac jelly, which comprises the following steps:

[0014] (1) adding sodium alginate to the natto active substance of claim 3 for embedding to obtain a mixture, mixing and cross-linking the mixture with calcium lactate in a mass ratio of (1-1.1):(3-3.2) to obtain sodium alginate microspheres encapsulating the natto active substance;

[0015] (2) mixing the sodium alginate microspheres encapsulating the natto active substance and the chitosan solution in a mass ratio of (1-1.1):(2-2.2) to form chitosan-sodium alginate gel microspheres;

[0016] (3) Mixing 0.7-1.6 parts of a gelling agent, 5-15 parts of a sweetener and 0.1-0.4 parts of konjac flour by weight, adding 40.6-85.1 parts of water while stirring, stirring and heating to cook the ingredients, cooling the ingredients after cooking, and adding 4-10 parts of chitosan-sodium alginate gel microspheres to obtain natto konjac jelly.

[0017] Preferably, the mass ratio of the natto active substance to sodium alginate is (1-1.1):(3-3.3).

[0018] Preferably, the gelling agent comprises carrageenan and locust bean gum.

[0019] Preferably, the sweetener is white sugar.

[0020] Preferably, in step (3), the stirring speed is 115-120 r / min.

[0021] Preferably, the cooking material is cooled down after cooking, and 0-0.4 parts of essence are added for flavoring.

[0022] Preferably, 0.1-0.3 parts of acid and 5-15 parts of fruit juice may be added during the flavoring stage to further adjust the flavor of the jelly.

[0023] Preferably, the acid solution comprises citric acid and / or malic acid.

[0024] Preferably, the fruit juice is selected from one of apple juice, orange juice and grape juice.

[0025] The present invention has the following technical effects:

[0026] The preparation method of the natto active substance of the present invention is simple, and the leaching rate of the natto active substance is improved and the impurity protein therein is removed by leaching and secondary salting out of mature natto under certain conditions, thereby improving the purity of the natto active substance. The natto flavor konjac jelly prepared by the method can maintain the natto flavor, improve the taste, toughness and texture of the jelly, and maintain a good appearance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0028] Figure 1 This is the situation of the konjac jelly sample prepared by the natto active substance of Example 1 using the preparation method of the present invention after one month;

[0029] Figure 2 This is the situation of the konjac jelly sample obtained by using the preparation method of the present invention to prepare the natto active substance in Example 1 after 3 months;

[0030] Figure 3 This is the situation of the konjac jelly sample kept 6 months after the natto active substance in Example 1 was prepared by the preparation method of the present invention;

[0031] Figure 4 This is the situation of the konjac jelly sample prepared by the natto active substance of Example 1 using the preparation method of the present invention after 9 months;

[0032] Figure 5 This is the situation of the konjac jelly sample obtained by using the natto active substance of Example 1 using the preparation method of the present invention after being kept for 12 months; DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0035] In order to more fully understand the technical content of the present invention, the technical solution of the present invention is further introduced and illustrated in conjunction with specific embodiments below.

[0036] Specifically, in the following embodiments, the method for preparing mature natto comprises the following steps:

[0037] The soybeans were washed and high-pressure steamed at 121°C for 45 minutes, cooled to room temperature, and 35 ml of natto bacteria powder was added for fermentation to obtain mature natto.

[0038] Example 1

[0039] A method for preparing a natto active substance comprises the following steps:

[0040] S1. Mix the mature natto with physiological saline in a volume ratio of 1:2, stir lightly, and extract for 24 hours. Centrifuge the obtained extract at 7000 r / min for 20 minutes, discard the precipitate, and obtain a crude extract.

[0041] S2. Take 28 ml of the crude extract obtained by leaching, add 12 ml of ammonium sulfate solution while stirring, use 30% saturation ammonium sulfate solution to perform salting out once, after standing for 1 hour, centrifuge once at 7000 rpm for 10 minutes, discard the precipitate, and obtain the supernatant; take 36 ml of the supernatant, add 48 ml of saturated ammonium sulfate solution to 70% saturation, perform secondary salting out, after standing for 1 hour, centrifuge twice at 7000 rpm for 10 minutes, discard the supernatant, and obtain the natto active substance.

[0042] Example 2

[0043] A method for preparing a natto active substance comprises the following steps:

[0044] S1. Mix mature natto and physiological saline in a volume ratio of 1:2, stir lightly, and extract for 26 hours. Centrifuge the obtained extract at 7150 r / min for 18 minutes, discard the precipitate, and obtain a crude extract.

[0045] S2. Take 30 ml of the crude extract obtained by leaching, add 15 ml of ammonium sulfate solution while stirring, use 30% saturation ammonium sulfate solution to perform salting out once, after standing for 1 hour, centrifuge once at 7000 rpm for 10 minutes, discard the precipitate, and obtain the supernatant; take 36 ml of the supernatant, add 48 ml of saturated ammonium sulfate solution to 70% saturation, perform secondary salting out, after standing for 1 hour, centrifuge twice at 7000 rpm for 10 minutes, discard the supernatant, and obtain the natto active substance.

[0046] Example 3

[0047] A method for preparing a natto active substance comprises the following steps:

[0048] S1. Mix mature natto and physiological saline in a volume ratio of 1:2.2, stir lightly, and extract for 25 hours. Centrifuge the obtained extract at 7200 r / min for 15 minutes, discard the precipitate, and obtain a crude extract.

[0049] S2, take 28ml of the crude extract obtained by leaching, add 13ml of ammonium sulfate solution while stirring, use 30% saturation ammonium sulfate solution to perform salting out once, after standing for 1h, centrifuge once at a speed of 7000 rpm for 10 minutes, discard the precipitate, and obtain; supernatant; take 36ml of the supernatant and add 48ml of saturated ammonium sulfate solution to 70% saturation, perform secondary salting out, after standing for 1h, centrifuge twice at a speed of 7000 rpm for 10 minutes, discard the supernatant, and obtain natto active substances.

[0050] Example 4

[0051] A method for preparing a natto active substance comprises the following steps:

[0052] S1. Mix mature natto and physiological saline in a volume ratio of 1.1:2, stir lightly, and extract for 24 hours. Centrifuge the obtained extract at 7100 r / min for 15 minutes, discard the precipitate, and obtain a crude extract.

[0053] S2, take 30ml of the crude extract obtained by leaching, add 15ml of saturated ammonium sulfate solution while stirring, use 30% saturated ammonium sulfate solution to perform salting out once, after standing for 1h, centrifuge once at 7000 rpm for 10 minutes, discard the precipitate, and obtain; supernatant, take 36ml of the supernatant and add 48ml of saturated ammonium sulfate solution to 70% saturation, perform secondary salting out, after standing for 1h, centrifuge twice at 7000 rpm for 10 minutes, discard the supernatant, and obtain natto active substances.

[0054] Example 5

[0055] A method for preparing a natto active substance comprises the following steps:

[0056] S1. Mix mature natto and physiological saline in a volume ratio of 1:2, stir lightly, and extract for 26 hours. Centrifuge the obtained extract at 7200 r / min for 20 minutes, discard the precipitate, and obtain a crude extract.

[0057] S2, take 30ml of the crude extract obtained by leaching, add 14ml of ammonium sulfate solution while stirring, use 30% saturation ammonium sulfate solution to perform salting out once, after standing for 1h, centrifuge once at a speed of 7000 rpm for 10 minutes, discard the precipitate, and obtain; supernatant, take 36ml of the supernatant, add 48ml of saturated ammonium sulfate solution to 70% saturation, perform secondary salting out, after standing for 1h, centrifuge twice at a speed of 7000 rpm for 10 minutes, discard the supernatant, and obtain natto active substances.

[0058] In order to illustrate the technical effect of the present invention, comparative examples 1-5 are set on the basis of the above embodiments as follows:

[0059] Comparative Example 1

[0060] The difference between this comparative example and Example 1 is that the extraction time is 20 h.

[0061] Comparative Example 2

[0062] The difference between this comparative example and Example 2 is that the centrifugation time in step S1 is 10 min.

[0063] Comparative Example 3

[0064] The difference between this comparative example and Example 3 is that the centrifugal rotation speed in step S1 is 8000 r / min.

[0065] Comparative Example 4

[0066] The difference between this comparative example and Example 4 is that the ammonium sulfate solution with a saturation of 20% is used in the first salting out.

[0067] Comparative Example 5

[0068] The difference between this comparative example and Example 5 is that during the secondary salting out, a saturated ammonium sulfate solution is added to the supernatant to a saturation of 60%.

[0069] The crude extracts of Examples 1-3 and Comparative Examples 1-3 were diluted 50 times, and then the absorbance values ​​at 260nm and 280nm were tested by an ultraviolet spectrophotometer and the protein content was tested; the supernatant after the first salting out of Example 4 and Comparative Example 4 was diluted 50 times, and then the absorbance values ​​at 260nm and 280nm were tested by an ultraviolet spectrophotometer and the protein content was tested; the natto active substances obtained in Example 5 and Comparative Example 5 were dissolved in 2ml of 0.01mol / L phosphate buffer with a pH of 7.4-7.6, and 0.5ml was taken for each dilution 50 times, and then the absorbance values ​​at 260nm and 280nm were tested by an ultraviolet spectrophotometer and the protein content was tested. The results of the above tests are shown in Table 1 below:

[0070] Table 1 Absorbance and protein content test results

[0071]

[0072] As shown in Table 1, when the extraction time and centrifugal conditions in step S1 of the present invention are changed, the protein content in the crude extract is reduced to a certain extent compared with the embodiments of the present application, indicating that the method of the present invention can significantly improve the extraction rate of active substances such as nattokinase. When a salting out is performed using an ammonium sulfate solution with a lower saturation, the impurity protein after the salting out cannot be completely removed. When a saturated ammonium sulfate solution is added to make its saturation too low using a secondary salting out, the desired protein cannot be effectively precipitated.

[0073] To further illustrate the technical effect of the natto active substance of the present invention, the natto active substances of Examples 1-5 and Comparative Examples 1-5 were used to prepare natto-flavored konjac jelly under the same conditions, and the prepared natto-flavored konjac jelly was subjected to sensory evaluation in terms of color (20 points in total), flavor (20 points in total) and texture (10 points in total).

[0074] The preparation method of natto flavored konjac jelly is as follows:

[0075] (1) mixing and embedding natto active substances and sodium alginate in a mass ratio of 1:3 to obtain a mixture, and mixing and cross-linking the mixture with calcium lactate in a mass ratio of 1:3 to obtain sodium alginate microspheres encapsulating natto active substances;

[0076] (2) mixing the sodium alginate microspheres encapsulating the active substance of natto and the chitosan solution at a mass ratio of 1:2 to form chitosan-sodium alginate gel microspheres;

[0077] (3) According to the mass percentage, 1 part of carrageenan, 0.3 parts of konjac flour, 0.2 parts of locust bean gum and 10 parts of white sugar were mixed evenly, and then put into a cooking tank and stirred at a speed of 120r / min. 65 parts of water were added while stirring. After the water was completely added, the temperature was heated to 90°C and then stopped. The stirring paddle was kept on and kept warm for 3 minutes. When the temperature of the liquid dropped to 50°C, the speed was adjusted to 85r / min;

[0078] (4) Transfer the above liquid to a fragrance blending tank, add 0.3 parts of essence for fragrance blending, then add 6 parts of orange juice and 0.3 parts of citric acid, and store at 75°C for 30 minutes;

[0079] (5) The prepared liquid is cooled and mixed with 8 parts of chitosan-sodium alginate gel microspheres, and filled into a packaging container by a filling machine. After sealing, sterilizing, and cooling, a packaged natto-flavored konjac jelly is obtained.

[0080] The sensory evaluation results are shown in Table 2 below:

[0081] Table 2 Sensory evaluation table

[0082]

[0083]

[0084] As shown in Table 2, the natto active substances in different embodiments and comparative examples have different degrees of sensory effects on the jelly prepared therefrom. Further analysis combined with Table 1 shows that when the extraction time and centrifugation conditions in step S1 of the present invention are changed, the extracted natto active substances are less, resulting in less natto flavor substances in the jelly, and the purpose of preparing natto flavor konjac jelly is not achieved. When salting out is performed using an ammonium sulfate solution with a low saturation, the impurity protein after salting out cannot be completely removed, resulting in the target active substance nattokinase containing impurity protein and the purity of the natto flavor active substance in the jelly being low. At the same time, the jelly texture will be hard and lose the Q elasticity that the jelly should have, and the product taste is not harmonious.

[0085] Furthermore, in order to illustrate the effect of the preparation method of the natto-flavored konjac jelly of the present invention on the final product, the natto-flavored konjac jelly was prepared using the natto active substance prepared in Example 1 according to the above method.

[0086] Based on the above method, comparative examples 6-8 are set as follows:

[0087] Comparative Example 6

[0088] The difference between this comparative example and the above method is that the steps (1) and (2) are not included, and the chitosan-sodium alginate gel microspheres in step (5) are replaced by natto active substances.

[0089] Comparative Example 7

[0090] The difference between this comparative example and the above method is that step (2) is not included and calcium lactate is not used for cross-linking, that is, the mixture in step (1) is used to replace the chitosan-sodium alginate gel microspheres in step (5).

[0091] Comparative Example 8

[0092] The difference between this comparative example and the above method is that step (2) is not included, and the chitosan-sodium alginate gel microspheres in step (5) are replaced by sodium alginate microspheres encapsulating the natto active substance in step (1).

[0093] The natto-flavored konjac jelly prepared by the preparation method of the present invention in Example 1 and the jelly prepared in Comparative Examples 6-8 were diluted 10 times and then tested for absorbance at 260 nm and 280 nm using an ultraviolet spectrophotometer and their protein content. The test results are shown in Table 3 below:

[0094] Table 3 Test results of protein in jelly

[0095]

[0096] As shown in Table 3, since the active substance in natto is an alkaline protein, the protein is easily denatured and inactivated under high temperature and acidic conditions. If the substance is directly used in the production of konjac jelly, the active substance in natto is very likely to be inactivated and denatured during the entire production process, resulting in a significant reduction in the content of the active substance in the final product.

[0097] Finally, in order to illustrate the stability of the natto-flavored konjac jelly of the present invention, the natto-flavored konjac jelly prepared in Example 1 was subjected to a sample test, and the color, transparency and flavor changes of the liquid were observed after 1 month, 3 months, 6 months, 9 months and 12 months of sample retention. Figure 1-5 shown.

[0098] It can be seen from the figure that within 12 months, as the sample retention time increased, the color and transparency of the jelly liquid did not change significantly.

[0099] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for preparing natto active substances, characterized in that: The following steps are involved: S1. Mix the mature natto and physiological saline in a volume ratio of (1-1.1): (2-2.2) and extract for 24h-26h, centrifuge and filter the obtained extract, retain the supernatant, and obtain a crude extract; S2. The crude extract and a 30%-32% saturation ammonium sulfate solution are mixed in a volume ratio of (28-32): (12-15) to perform a salting out, and then centrifuge once. A saturated ammonium sulfate solution is added to the supernatant of the first salting out to a saturation of 70%-72%, and a second salting out is performed. Then, a second centrifuge is performed to obtain a precipitate to obtain a natto active substance.

2. The method for preparing the natto active substance according to claim 1, characterized in that: The mass ratio of the supernatant to the saturated ammonium sulfate solution is (35-37):(46-48).

3. The method for preparing the natto active substance according to claim 1, characterized in that: The centrifugal speed is 7000-7200 r / min, and the time is 15-20 min.

4. The method for preparing the natto active substance according to claim 1, characterized in that: The method for preparing the mature natto is as follows: washing soybeans, steaming them under high pressure at 121° C. for 40-45 minutes, cooling them to room temperature, adding 30-35 ml of natto bacteria powder for fermentation, and obtaining mature natto.

5. A natto active substance, characterized in that: The natto active substance is prepared by the method for preparing the natto active substance according to any one of claims 1 to 4.

6. A natto konjac jelly, characterized in that: The invention comprises the natto active substance as claimed in claim 5.

7. A method for preparing natto konjac jelly, characterized in that: The following steps are involved: (1) adding sodium alginate to the natto active substance of claim 5 for embedding to obtain a mixture, mixing and cross-linking the mixture with calcium lactate in a mass ratio of (1-1.1):(3-3.2) to obtain sodium alginate microspheres encapsulating the natto active substance; (2) mixing the sodium alginate microspheres encapsulating the natto active substance and the chitosan solution in a mass ratio of (1-1.1):(2-2.2) to form chitosan-sodium alginate gel microspheres; (3) Mixing 0.7-1.6 parts of a gelling agent, 5-15 parts of a sweetener and 0.1-0.4 parts of konjac flour by weight, adding 40.6-85.1 parts of water while stirring, stirring and heating to cook the ingredients, cooling the ingredients after cooking, and adding 4-10 parts of chitosan-sodium alginate gel microspheres to obtain natto konjac jelly.

8. The method for preparing natto konjac jelly according to claim 7, characterized in that: The mass ratio of the natto active substance to the sodium alginate is (1-1.1):(3-3.3).

9. The method for preparing natto konjac jelly according to claim 7, characterized in that: The gelling agent comprises carrageenan and locust bean gum.

10. The method for preparing natto konjac jelly according to claim 7, characterized in that: After the cooking is finished, the process also includes flavoring.

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