A preparation method and application of konjac micro-powder

Abstract

The present invention discloses a preparation method and application of konjac fine powder, which relates to the technical field of food processing. The preparation method of the konjac fine powder comprises the following steps: S1. Ultrafine pulverization treatment: The crude konjac powder is subjected to ultrafine pulverization treatment to obtain konjac powder with a particle size D50 lower than 15.0 μm; S2. Electric pulse treatment: The konjac powder after the ultrafine pulverization treatment in S1 is placed in a pulsed electric field processor for the treatment of strengthening the tissue shrinkage elasticity of the konjac fine powder to obtain konjac fine powder; the parameters of the pulsed electric field processor are: electric field strength 10 - 20 kV / cm, pulse width 5 - 50 μs, pulse frequency 100 - 800 Hz, flow rate 100 - 200 g / min, and pulsed electric field treatment time 10 - 30 min. The konjac fine powder prepared by the preparation method of the present invention has good homogeneity, fluidity and warm water solubility, and the tissue shrinkage elasticity is increased by 30%, and the flavor, taste and nutritional value can be effectively preserved; the konjac jelly prepared by using the konjac fine powder of the present invention has good gelatinous texture, is not prone to water separation and has a relatively long shelf life.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing, and in particular to a preparation method and application of konjac micro-powder. Background Art

[0002] Konjac, also known as Amorphophallus konjac, has the characteristics of low calories, low protein, and high dietary fiber, and is an ideal raw material for weight loss foods. At the same time, konjac powder is rich in glucomannan. Glucomannan is a high-molecular plant polysaccharide, belonging to soluble hemicellulose, and is rich in hydroxyl groups (-OH). Moreover, konjac powder has strong water absorption and swelling properties, emulsifying properties, thickening properties, and gelling properties, etc., is less affected by acids and salts, and has good stability. When it is used in the processing of jelly foods, it can improve the physical properties of jelly, endow the food with a smooth taste, and increase the gel property of jelly. To meet the characteristics of clear and translucent jelly, the quality requirements for raw materials are very high. Generally, konjac jelly is produced by mixing deionized water, high-concentration fruit juice solution and konjac powder and then filtering.

[0003] At present, the konjac powder on the market is mainly crude konjac powder and desulfurized konjac refined powder. The crude konjac powder has large particle size and many impurities; the desulfurized konjac refined powder is obtained by soaking the crude konjac powder in alcohol, then pressing and filtering to dehydrate, high-pressure backwashing, grinding, soaking in alcohol again, pressing and filtering to dehydrate for the second time, vacuum drying and other processes to remove fibers, starch, impurities, SO2, etc. However, the current desulfurized konjac refined powder has problems such as low glucomannan content and poor taste, and is not suitable for the production and technical requirements of high-tenacity extruded konjac jelly. Konjac jelly products made from crude konjac powder or desulfurized konjac refined powder have problems such as difficult filtering process and low efficiency. The products prepared have quality problems such as low glucomannan content, soft taste, easy water separation, etc. At the same time, the content of nutritional substances such as dietary fiber is low, and the product shelf life is only about 6 months, which cannot meet the needs of consumers and is not conducive to product promotion. 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 preparation method and application of konjac micro-powder. The konjac micro-powder prepared by the present invention is used in the process of preparing konjac jelly, which is simple, and the prepared jelly has a high glucomannan content, good taste, is not easy to separate water, and has a long shelf life.

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

[0006] In the first aspect, the present invention provides a method for preparing konjac micro-powder, including the following steps:

[0007] S1. Ultrafine pulverization treatment; the crude konjac powder is subjected to ultrafine pulverization treatment to obtain konjac powder with a particle size D50 lower than 15.0 μm;

[0008] S2. Electric pulse treatment: The konjac powder after ultrafine grinding in S1 is placed in a pulsed electric field processor for strengthening the tissue shrinkage elasticity of the konjac micro-powder to obtain konjac micro-powder.

[0009] The parameters of the pulsed electric field processor are as follows: electric field strength 10 - 20 kV / cm, pulse width 5 - 50 μs, pulse frequency 100 - 800 Hz, flow rate 100 - 200 g / min, and pulsed electric field treatment time 10 - 30 min.

[0010] Furthermore, the ultrafine grinding treatment in step S1 is carried out in an ultrafine grinder; the power of the ultrafine grinder is 22 - 45 KW / h.

[0011] Furthermore, the ultrafine grinding treatment can break some glycosidic bonds of the glucomannan main chain through high-speed shear force, degrade to generate monosaccharides, and at the same time, some sugar chains are broken, resulting in a decrease in molecular weight, a loose structure, and the exposure of more active groups such as hydroxyl groups, effectively improving the interfacial activity of konjac powder, promoting the dissolution of active ingredients, increasing the antioxidant activity, enhancing the homogeneity, fluidity and warm water solubility of konjac powder, and preserving the flavor, taste and nutritional value of konjac powder.

[0012] Furthermore, the tissue shrinkage elasticity (gel strength) of the konjac jelly prepared from the konjac micro-powder after electric pulse treatment within the parameter range of this application can be enhanced by 25% - 35%.

[0013] In the second aspect, the present invention provides a konjac micro-powder prepared by the above method.

[0014] Furthermore, applying the above konjac micro-powder to jelly products can solve problems such as difficult filtration in jelly production, loss of nutrients, easy water separation, short shelf life, etc., and at the same time greatly improve the elastic and tough texture of jelly.

[0015] In the third aspect, the present invention provides a modified composite colloid solution, which is composed of the following components in mass percentage:

[0016] The konjac micro-powder as described in the second aspect: 15 - 20%;

[0017] Resistant dextrin: 1 - 2%;

[0018] Locust bean gum: 0.1 - 1%;

[0019] Pullulanase: 0.1 - 0.5%;

[0020] The balance is process water.

[0021] In the fourth aspect, the present invention provides a preparation method of the modified composite colloid solution described in the third aspect, including the following steps:

[0022] 1) Mixed gum preparation: Put konjac micro - powder, process water, resistant dextrin and locust bean gum into a boiling tank and mix evenly. Heat up to 45 - 60 °C and use a five - hole hemispherical turbine powder tank stirring head to stir for 10 - 30 minutes to obtain a composite colloid solution with konjac powder as the main body.

[0023] 2) Enzymatic modification: Add pullulanase to the composite colloid solution, keep warm and stir for 2 - 4 hours to obtain a modified composite colloid solution.

[0024] Furthermore, using pullulanase for enzymatic modification can reduce the content of galactose in konjac powder and locust bean, reduce the molecular weight and viscosity of konjac powder, but does not change the main structure of the main chain of konjac powder, the configuration of glucomannan glycosidic bonds and rheological properties. The prepared composite colloid solution can form a rhombic network structure after cooling, has a strong yield stress, and can maintain a high elastic modulus within a higher pressure range.

[0025] In the fifth aspect, the present invention provides a konjac jelly, which is composed of the following components in mass percentage: 5 - 15% of the modified composite colloid as described in the third aspect, 20 - 30% of fruit juice, 10 - 20% of syrup, 0.1 - 0.5% of citric acid, 0.1 - 0.5% of calcium lactate, 0.05 - 0.2% of potassium chloride, 0.05 - 0.2% of sodium citrate, 0.01 - 0.05% of potassium sorbate, 0.01 - 0.1% of edible essence, and the balance is process water.

[0026] In the sixth aspect, the present invention provides a preparation method of the konjac jelly as described in the fifth aspect, including the following steps:

[0027] (1) Jelly liquid preparation: Heat the modified composite colloid to above 70 °C, add process water, fruit juice, syrup, citric acid, calcium lactate, potassium chloride, sodium citrate, potassium sorbate and edible essence, heat up to 96 ± 2 °C, and stir for 10 - 15 minutes until fully uniform to obtain jelly liquid.

[0028] (2) Homogenization treatment: Treat the jelly liquid with a two - stage homogenization process to make a semi - finished jelly liquid, and store it in a constant - temperature (37 °C ± 1 °C) stirring tank for later use.

[0029] (3) Filtration: Filter the semi - finished jelly liquid after homogenization through a candle filter with a pore size of 200 meshes to effectively remove foreign matters and impurities in the liquid. Place the filtered liquid in a temporary storage tank for later use and keep it warm at a temperature above 70 °C.

[0030] (4) Filling: Place the filtered liquid at the filling machine, filter it twice, the filter bag is configured with 60 meshes, and automatically fill the filtered liquid to obtain a semi - finished konjac jelly.

[0031] (5) Sterilization; The semi-finished konjac jelly after filling must be pasteurized within 10 minutes, with a sterilization temperature of 85.5 ± 1.5 °C and a sterilization time of 8 ± 0.5 minutes;

[0032] (6) Packaging; The semi-finished konjac jelly after sterilization is cooled, dried and other processes to obtain konjac jelly, which is packaged and stored in the warehouse for finished product inspection.

[0033] Furthermore, the pressure of the first stage of the two-stage homogenization process is 18 - 22 MPa, and the pressure of the second stage is 3 - 5 MPa.

[0034] The present invention has the following technical effects:

[0035] 1. The konjac micro-powder prepared by the present invention has good homogeneity, fluidity and warm water solubility, and the flavor, taste and nutritional value can be effectively preserved;

[0036] 2. The tissue shrinkage elasticity (gel strength) of the konjac micro-powder prepared by the present invention is enhanced by 25 - 35%;

[0037] 3. The konjac jelly prepared by using the konjac micro-powder of the present invention has good gel texture, is not easy to exude water and has a long shelf life. Description of the Drawings

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0039] Figure 1 Process flow chart of konjac jelly preparation;

[0040] Figure 2 For Example 1, comparison chart of the gum mass before heating in the cooking vat for Comparative Example 1 and 2;

[0041] Figure 2 a) Gum mass situation of Example 1 before heating in the cooking vat;

[0042] Figure 2 b) Gum mass situation of Comparative Example 1 before heating in the cooking vat;

[0043] Figure 2 c) Gum mass situation of Comparative Example 2 before heating in the cooking vat;

[0044] Figure 3 For Example 1, comparison chart of the gum mass after heat preservation in the cooking vat for Comparative Example 1 and 2;

[0045] Figure 3a) The situation of the rubber pellets after heat preservation in the cooking vat for Example 1;

[0046] Figure 3 b) The situation of the rubber pellets after heat preservation in the cooking vat for Comparative Example 1;

[0047] Figure 3 c) The situation of the rubber pellets after heat preservation in the cooking vat for Comparative Example 2;

[0048] Figure 4 Comparison diagram of the rubber pellets at the bottom of the cooking vat after discharging for Example 1, Comparative Example 1 and Comparative Example 2;

[0049] Figure 4 a) The situation of the rubber pellets at the bottom of the cooking vat after discharging for Example 1;

[0050] Figure 4 b) The situation of the rubber pellets at the bottom of the cooking vat after discharging for Comparative Example 1;

[0051] Figure 4 c) The situation of the rubber pellets at the bottom of the cooking vat after discharging for Comparative Example 2;

[0052] Figure 5 Comparison diagram of the rubber pellets after secondary filtration by the filter bag for Example 1, Comparative Example 1 and Comparative Example 2;

[0053] Figure 5 a) The situation of the rubber pellets after secondary filtration by the filter bag for Example 1;

[0054] Figure 5 b) The situation of the rubber pellets after secondary filtration by the filter bag for Comparative Example 1;

[0055] Figure 5 c) The situation of the rubber pellets after secondary filtration by the filter bag for Comparative Example 2;

[0056] Figure 6 Comparison diagram of the rubber pellets after filtration of the composite colloid solution prepared in Example 1 and Comparative Example 3;

[0057] Figure 6 a) The situation of the rubber pellets after filtration of the composite colloid solution prepared in Example 1;

[0058] Figure 6 b) The situation of the rubber pellets after filtration of the composite colloid solution prepared in Comparative Example 3;

[0059] Figure 7 Comparison diagram of the konjac jelly prepared in Example 1 and Comparative Example 4; The konjac jelly prepared in Comparative Example 4 is on the left; The konjac jelly prepared in Example 1 is on the right;

[0060] Figure 8Comparison of the water separation of the konjac jelly prepared in Example 1 and Comparative Example 1 after 6 months of sample retention; on the left is the water separation of the konjac jelly prepared in Example 1 after 6 months of sample retention; on the right is the water separation of the konjac jelly prepared in Comparative Example 1 after 6 months of sample retention;

[0061] Figure 9 Comparison of the situation of the konjac jelly prepared in Example 1 and Comparative Example 1 after 12 months of sample retention;

[0062] Figure 9 a) shows the situation of the konjac jelly prepared in Example 1 after 12 months of sample retention;

[0063] Figure 9 b) shows the situation of the konjac jelly prepared in Comparative Example 1 after 12 months of sample retention; Detailed implementation manners

[0064] Next, in combination with the embodiments of the present invention, the technical solutions of the present invention will be clearly and completely described. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0065] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their combinations.

[0066] To more fully understand the technical content of the present invention, the technical solutions of the present invention will be further introduced and described below in combination with specific embodiments.

[0067] The present invention provides a method for preparing konjac jelly, comprising the following steps:

[0068] S1. Ultrafine pulverization treatment; the crude konjac powder is subjected to ultrafine pulverization treatment to obtain konjac powder with a particle size D50 lower than 15.0 μm;

[0069] S2. Electro-pulse treatment; the konjac powder after the ultrafine pulverization treatment in S1 is placed in a pulsed electric field processor for the treatment of strengthening the tissue shrinkage elasticity of the konjac micro-powder to obtain konjac micro-powder;

[0070] The parameters of the pulsed electric field processor are: electric field strength 10 - 20 kV / cm, pulse width 5 - 50 μs, pulse frequency 100 - 800 Hz, flow rate 100 - 200 g / min, and pulsed electric field treatment time 10 - 30 min.

[0071] S3. Mixed gum preparation: Put 15 - 20% konjac micro - powder, 1 - 2% resistant dextrin, 0.1 - 1% locust bean gum, 0.1 - 0.5% pullulanase, and the balance process water into the cooking cylinder according to mass fraction, mix evenly, heat up to 45 - 60 °C, and stir with a five - hole hemispherical turbine powder cylinder stirring head for 10 - 30 minutes to obtain a composite colloid solution;

[0072] S4. Enzymatic modification: Add pullulanase to the composite colloid solution, keep warm and stir - react for 2 - 4 hours to obtain a modified composite colloid solution;

[0073] S5. Jelly liquid preparation: Heat the modified composite colloid solution with a mass fraction of 5 - 15% to above 70 °C, add 20 - 30% fruit juice, 10 - 20% syrup, 0.1 - 0.5% citric acid, 0.1 - 0.5% calcium lactate, 0.05 - 0.2% potassium chloride, 0.05 - 0.2% sodium citrate, 0.01 - 0.05% potassium sorbate, 0.01 - 0.1% edible essence according to mass fraction, and the balance process water, heat up to 96 °C, and stir for 10 - 15 minutes until fully uniform to obtain a jelly liquid;

[0074] S6. Homogenization treatment: Treat the jelly liquid with a two - stage homogenization process. The pressure of the first stage is 18 - 22 MPa, and the pressure of the second stage is 3 - 5 MPa to make a semi - finished jelly liquid;

[0075] S7. Filtration: Filter the semi - finished jelly liquid after homogenization through a candle - type filter with a 200 - mesh aperture to ensure that foreign matters and impurities in the liquid can be effectively removed. The filtered liquid is placed in a storage tank and kept warm at a temperature above 70 °C;

[0076] S8. Filling: Place the filtered liquid at the filling machine, filter it twice. The filter bag is configured with 60 meshes, and the filtered liquid is automatically filled to obtain a semi - finished konjac jelly;

[0077] S9. Sterilization: The semi - finished konjac jelly after filling must be subjected to pasteurization within 10 minutes. The sterilization temperature is 85.5 ± 1.5 °C, and the sterilization time is 8 ± 0.5 minutes;

[0078] S10. Packaging: The semi - finished konjac jelly after sterilization is cooled, dried and other processes to obtain konjac jelly, which is packaged and stored in the warehouse for finished product inspection.

[0079] (I) Examples and comparative examples:

[0080] Example 1

[0081] A preparation method of konjac jelly, comprising the following steps:

[0082] S1. Ultrafine grinding treatment: Coarse konjac powder is subjected to ultrafine grinding treatment to obtain konjac powder with a D50 particle size below 15.0 μm.

[0083] S2. Electro-pulse treatment: The konjac powder after the ultrafine grinding treatment in S1 is placed in a pulsed electric field processor for tissue shrinkage elasticity strengthening treatment of konjac micro-powder to obtain konjac micro-powder.

[0084] The parameters of the pulsed electric field processor are as follows: electric field strength 15 kV / cm, pulse width 30 μs, pulse frequency 600 Hz, flow rate 150 g / min, and pulsed electric field treatment time 20 min.

[0085] S3. Mixing and gum preparation: 18% konjac micro-powder, 80% process water, 1.5% resistant dextrin, and 0.5% locust bean gum are put into a cooking cylinder according to mass fraction, mixed evenly, heated to 45 °C, and stirred with a five-hole hemispherical turbine powder cylinder stirring head for 30 minutes to obtain a composite colloid solution.

[0086] S4. Enzymatic modification: Pullulanase is added to the composite colloid solution, and the mixture is kept warm and stirred for reaction for 3 hours to obtain a modified composite colloid solution.

[0087] S5. Jelly liquid preparation: The modified composite colloid solution with a mass fraction of 10% is heated to 85 °C, and 48.3% process water, 25% fruit juice, 16% syrup, 0.2% citric acid, 0.2% calcium lactate, 0.1% potassium chloride, 0.1% sodium citrate, 0.05% potassium sorbate, and 0.05% edible essence are added according to mass fraction. Then it is heated to 96 °C and stirred for 10 minutes until fully uniform to obtain a jelly liquid.

[0088] S6. Homogenization treatment: The jelly liquid is treated by a two-stage homogenization process. The pressure in the first stage is 20 MPa, and the pressure in the second stage is 4 MPa to make a semi-finished jelly liquid.

[0089] S7. Filtration: The semi-finished jelly liquid after homogenization treatment is filtered through a candle filter with a 200-mesh aperture to ensure that foreign matters and impurities in the liquid can be effectively removed. The filtered liquid is placed in a storage tank and kept warm at a temperature of 85 °C for standby.

[0090] S8. Filling: The filtered liquid is placed at a filling machine, filtered twice, the filter bag is configured with 60 meshes, and the filtered liquid is automatically filled to obtain a semi-finished konjac jelly.

[0091] S9. Sterilization: The semi-finished konjac jelly after filling must be subjected to pasteurization within 10 minutes. The sterilization temperature is 85.5 ± 1.5 °C, and the sterilization time is 8 ± 0.5 min.

[0092] S10. Packaging; The semi-finished konjac jelly after sterilization is cooled, dried and other processes to obtain konjac jelly, which is packaged and stored in the warehouse for finished product inspection.

[0093] Example 2

[0094] A preparation method of konjac jelly includes the following steps:

[0095] S1. Ultrafine grinding treatment; The crude konjac powder is subjected to ultrafine grinding treatment to obtain konjac powder with a particle size D50 below 15.0 μm.

[0096] S2. Electro-pulse treatment; The konjac powder after the S1 ultrafine grinding treatment is placed in a pulsed electric field processor for tissue shrinkage and elasticity strengthening treatment of konjac micro-powder to obtain konjac micro-powder.

[0097] The parameters of the pulsed electric field processor are: electric field strength 10 kV / cm, pulse width 5 μs, pulse frequency 800 Hz, flow rate 100 g / min, and pulsed electric field treatment time 30 min.

[0098] S3. Mixing and gelling; Mix 15% konjac micro-powder, 82.9% process water, 1% resistant dextrin and 0.1% locust bean gum evenly by mass fraction, heat up to 50 °C, and stir for 20 minutes to obtain a composite colloid solution.

[0099] S4. Enzymatic modification; Add pullulanase to the composite colloid solution, keep warm and stir for 2 hours to obtain a modified composite colloid solution.

[0100] S5. Jelly liquid preparation; Heat the modified composite colloid solution with a mass fraction of 8% to 70 °C, add 53.88% process water, 20% fruit juice, 20% syrup, 0.5% citric acid, 0.5% calcium lactate, 0.05% potassium chloride, 0.05% sodium citrate, 0.01% potassium sorbate and 0.01% edible essence by mass fraction, heat up to 95 °C, and stir for 15 minutes until fully uniform to obtain jelly liquid.

[0101] S6. Homogenization treatment; The jelly liquid is treated by a two-stage homogenization process, with the first stage pressure of 18 MPa and the second stage pressure of 3 MPa to make semi-finished jelly liquid.

[0102] S7. Filtration; The semi-finished jelly liquid after homogenization treatment is filtered through a candle filter with a pore size of 200 meshes to ensure that foreign matters and impurities in the liquid can be effectively removed. The filtered liquid is placed in a temporary storage tank and kept warm at a temperature of 70 °C.

[0103] S8. Filling; Place the filtered liquid at the filling machine, filter it twice, with the filter bag configured as 60 meshes, and automatically fill the filtered liquid to obtain semi-finished konjac jelly.

[0104] S9, Sterilization; The semi-finished konjac jelly after filling must be pasteurized within 10 minutes, with a sterilization temperature of 85.5 ± 1.5 °C and a sterilization time of 8 ± 0.5 minutes;

[0105] S10, Packaging; The semi-finished konjac jelly after sterilization is cooled, dried and other processes to obtain konjac jelly, which is packaged and stored in the warehouse for finished product inspection.

[0106] Based on Example 1, Comparative Example 1 and Comparative Example 2 are set. The difference between Comparative Example 1 and Example 1 is only that the konjac micro-powder used is commercially available konjac refined powder; the difference between Comparative Example 2 and Example 1 is only that enzymatic modification is not carried out. The technical solutions of Comparative Example 1 and Comparative Example 2 are as follows:

[0107] Comparative Example 1

[0108] A preparation method of konjac jelly, comprising the following steps:

[0109] S1, Mixing and making glue; Mix 18% commercially available desulfurized konjac refined powder, 80% process water, 1.5% resistant dextrin and 0.5% locust bean gum evenly by mass fraction, heat up to 45 °C, and stir for 30 minutes to obtain a composite colloid solution;

[0110] S2, Enzymatic modification; Add pullulanase to the composite colloid solution, keep warm and stir for 3 hours to obtain a modified composite colloid solution;

[0111] S3, Jelly liquid preparation; Heat the modified composite colloid solution with a mass fraction of 10% to 85 °C, add 48.3% process water, 25% fruit juice, 16% syrup, 0.2% citric acid, 0.2% calcium lactate, 0.1% potassium chloride, 0.1% sodium citrate, 0.05% potassium sorbate and 0.05% edible essence by mass fraction, heat up to 96 °C, and stir for 10 minutes until fully uniform to obtain jelly liquid;

[0112] S4, Homogenization treatment; Treat the jelly liquid with a two-stage homogenization process, with the first stage pressure of 20 MPa and the second stage pressure of 4 MPa to make semi-finished jelly liquid;

[0113] S5, Filtration; Filter the semi-finished jelly liquid after homogenization through a candle filter with a pore size of 200 meshes to ensure that foreign matters and impurities in the liquid can be effectively removed. The filtered liquid is placed in a storage tank and kept at a temperature of 85 °C for use;

[0114] S6, Filling; Place the filtered liquid at the filling machine, filter it twice, the filter bag is configured with 60 meshes, and the filtered liquid is automatically filled to obtain semi-finished konjac jelly;

[0115] S7, Sterilization; The semi-finished konjac jelly after filling must be pasteurized within 10 minutes, with a sterilization temperature of 85.5 ± 1.5 °C and a sterilization time of 8 ± 0.5 minutes;

[0116] S8, Packaging; The semi-finished konjac jelly after sterilization is cooled, dried and other processes to obtain konjac jelly, which is packaged and stored in the warehouse for finished product inspection.

[0117] Comparative Example 2

[0118] A method for preparing konjac jelly, comprising the following steps:

[0119] S1, Ultrafine grinding treatment; The crude konjac powder is subjected to ultrafine grinding treatment to obtain konjac powder with a particle size D50 below 15.0 μm;

[0120] S2, Electro-pulse treatment; The konjac powder after S1 ultrafine grinding treatment is placed in a pulsed electric field processor for tissue shrinkage and elasticity strengthening treatment of konjac micro-powder to obtain konjac micro-powder;

[0121] The parameters of the pulsed electric field processor are: electric field strength 15 kV / cm, pulse width 30 μs, pulse frequency 600 Hz, flow rate 150 g / min, and pulsed electric field treatment time 20 min.

[0122] S3, Mixing and gum preparation; 18% konjac micro-powder, 80% process water, 1.5% resistant dextrin and 0.5% locust bean gum are mixed evenly by mass fraction, heated to 45 °C, and stirred for 30 minutes to obtain a composite colloid solution;

[0123] S4, Jelly liquid preparation; The modified composite colloid solution with a mass fraction of 10% is heated to 85 °C, and 48.3% process water, 25% fruit juice, 16% syrup, 0.2% citric acid, 0.2% calcium lactate, 0.1% potassium chloride, 0.1% sodium citrate, 0.05% potassium sorbate and 0.05% edible essence are added by mass fraction, heated to 96 °C, and stirred for 10 minutes until fully uniform to obtain jelly liquid;

[0124] S5, Homogenization treatment; The jelly liquid is treated by a two-stage homogenization process, with the first stage pressure of 20 MPa and the second stage pressure of 4 MPa to make semi-finished jelly liquid;

[0125] S6, Filtration; The semi-finished jelly liquid after homogenization treatment is filtered through a candle filter with a pore size of 200 mesh to ensure that foreign matters and impurities in the liquid can be effectively removed. The filtered liquid is placed in a storage tank and kept at a temperature of 85 °C for use;

[0126] S7, Filling; The filtered liquid is placed at the filling machine, and after secondary filtration, the filter bag is configured with 60 mesh, and the filtered liquid is automatically filled to obtain semi-finished konjac jelly;

[0127] S8, Sterilization; The semi-finished konjac jelly after filling must be pasteurized within 10 minutes, with a sterilization temperature of 85.5 ± 1.5 °C and a sterilization time of 8 ± 0.5 minutes.

[0128] S9, Packaging; The semi-finished konjac jelly after sterilization is cooled, dried and other processes to obtain konjac jelly, which is packaged and stored in the warehouse for finished product inspection.

[0129] For Example 1, Comparative Examples 1 and 2, the rubber masses before the temperature rise of the cooking cylinder, the rubber masses after the cooking cylinder is kept warm, the rubber masses at the bottom of the cooking cylinder after the discharge of the cooking cylinder are confirmed, and the rubber masses after the secondary filtration of the filter bag are photographed and observed. The results are as Figure 2-5 , shown in Table 1:

[0130] Table 1 Observation results of the rubber masses before the temperature rise of the cooking cylinder, the rubber masses after the cooking cylinder is kept warm, the rubber masses at the bottom of the main material cylinder after the discharge of the main material cylinder, and the rubber masses after the secondary filtration of the filter bag in Example 1, Comparative Examples 1 and 2

[0131]

[0132] As shown in Table 1, the amount of rubber mass in the technical solution of the present invention is significantly less than that of Comparative Examples 1-2. The rubber masses in the liquid cannot be dispersed and dissolved again in the subsequent processes and do not play their due roles. More rubber masses will result in poor gel feeling and reduced elasticity of the prepared konjac jelly.

[0133] (2) To further verify the influence of the ultrafine pulverization step in the preparation method of the present invention on the performance of the prepared konjac micro-powder, Comparative Example 3 is set on the basis of Example 1. The difference between Comparative Example 3 and Example 1 is only that ultrafine pulverization treatment is not adopted, and the other steps are the same as those in Example 1.

[0134] Comparative Example 3

[0135] A preparation method of konjac jelly, comprising the following steps:

[0136] S1, Electro-pulse treatment; Coarse konjac powder with a particle size D50 of 125 μm is placed in a pulsed electric field processor for konjac micro-powder tissue shrinkage elasticity strengthening treatment to obtain konjac micro-powder;

[0137] The parameters of the pulsed electric field processor are: electric field strength 15 kV / cm, pulse width 30 μs, pulse frequency 600 Hz, flow rate 150 g / min, and pulsed electric field treatment time 20 min.

[0138] S2, Mixing and making glue; 18% konjac micro-powder, 80% process water, 1.5% resistant dextrin and 0.5% locust bean gum are put into the cooking cylinder according to mass fraction and mixed evenly, heated to 45 °C, and stirred with a five-hole hemispherical turbine powder cylinder stirring head for 30 minutes to obtain a composite colloid solution;

[0139] S3. Enzymatic modification: Pullulanase is added to the composite colloid solution, and the mixture is kept warm and stirred for 3 hours to obtain a modified composite colloid solution.

[0140] S4. Preparation of jelly liquid: The modified composite colloid solution with a mass fraction of 10% is heated to 85°C, and 48.3% process water, 25% fruit juice, 16% syrup, 0.2% citric acid, 0.2% calcium lactate, 0.1% potassium chloride, 0.1% sodium citrate, 0.05% potassium sorbate and 0.05% edible essence are added according to the mass fraction. Then it is heated to 96°C and stirred for 10 minutes until fully uniform to obtain the jelly liquid.

[0141] S5. Homogenization treatment: The jelly liquid is treated by a two-stage homogenization process. The pressure in the first stage is 20 MPa, and the pressure in the second stage is 4 MPa to obtain a semi-finished jelly liquid.

[0142] S6. Filtration: The semi-finished jelly liquid after homogenization treatment is filtered through a candle filter with a pore size of 200 meshes to effectively remove foreign matters and impurities in the liquid. The filtered liquid is placed in a storage tank and kept warm at a temperature of 85°C.

[0143] S7. Filling: The filtered liquid is placed at the filling machine, and after secondary filtration (the filter bag is configured with 60 meshes), the filtered liquid is automatically filled to obtain a semi-finished konjac jelly.

[0144] S8. Sterilization: The semi-finished konjac jelly after filling must be subjected to pasteurization within 10 minutes. The sterilization temperature is 85.5 ± 1.5°C, and the sterilization time is 8 ± 0.5 minutes.

[0145] S9. Packaging: The semi-finished konjac jelly after sterilization is cooled, dried and other processes to obtain konjac jelly, which is packaged and stored in the warehouse for finished product inspection.

[0146] The composite colloid solutions prepared in Example 1 and Comparative Example 3 are filtered, and their micelle conditions are observed as shown in Table 2. Figure 6 as shown.

[0147] Table 2 Micelle conditions of the composite colloid solutions prepared in Example 1 and Comparative Example 3 after filtration

[0148]

[0149]

[0150] (3) To further verify the effect of electro-pulse treatment on the preparation of konjac micro-powder, Comparative Example 4 is set on the basis of Example 1. The difference between Comparative Example 4 and Example 1 is only that electro-pulse treatment is not used, and the remaining steps are the same as those in Example 1.

[0151] Comparative Example 4

[0152] A method for preparing konjac jelly, comprising the following steps:

[0153] S1. Ultrafine grinding treatment: Coarse konjac powder is subjected to ultrafine grinding treatment to obtain konjac micro-powder with a particle size D50 below 15.0 μm;

[0154] S2. Mixing and gum preparation: 18% konjac micro-powder, 80% process water, 1.5% resistant dextrin and 0.5% locust bean gum are placed in a cooking tank according to mass fraction, mixed evenly, heated to 45 °C, and stirred with a five-hole hemispherical turbine powder cylinder stirring head for 30 minutes to obtain a composite colloid solution;

[0155] S3. Enzymatic modification: Pullulanase is added to the composite colloid solution, and the mixture is kept warm and stirred for reaction for 3 hours to obtain a modified composite colloid solution;

[0156] S4. Jelly liquid preparation: The modified composite colloid solution with a mass fraction of 10% is heated to 85 °C, and 48.3% process water, 25% fruit juice, 16% syrup, 0.2% citric acid, 0.2% calcium lactate, 0.1% potassium chloride, 0.1% sodium citrate, 0.05% potassium sorbate and 0.05% edible essence are added according to mass fraction, heated to 96 °C, and stirred for 10 minutes until fully uniform to obtain jelly liquid;

[0157] S5. Homogenization treatment: The jelly liquid is treated by a two-stage homogenization process, with the first-stage pressure being 20 MPa and the second-stage pressure being 4 MPa to produce semi-finished jelly liquid;

[0158] S6. Filtration: The semi-finished jelly liquid after homogenization treatment is filtered through a candle filter with a pore size of 200 mesh to ensure that foreign matters and impurities in the liquid can be effectively removed. The filtered liquid is placed in a storage tank and kept warm at a temperature of 85 °C;

[0159] S7. Filling: The filtered liquid is placed at a filling machine, filtered twice, the filter bag is configured with 60 mesh, and the filtered liquid is automatically filled to produce semi-finished konjac jelly;

[0160] S8. Sterilization: The semi-finished konjac jelly after filling must be subjected to pasteurization within 10 minutes, with a sterilization temperature of 85.5 ± 1.5 °C and a sterilization time of 8 ± 0.5 minutes;

[0161] S9. Packaging: The semi-finished konjac jelly after sterilization is cooled, dried and other processes to obtain konjac jelly, which is packaged and stored in the warehouse for finished product inspection.

[0162] Take the konjac jelly prepared in Example 1 and Comparative Example 4 as Figure 7 shown, and test its gel strength and melting point as shown in Table 3.

[0163] Table 3 Gel strength and melting point of konjac jelly prepared in Example 1 and Comparative Example 4

[0164] <![CDATA[Gel strength (g / cm 2 )]]> Melting point (°C) Example 1 268.7 64.3 Comparative Example 4 189.2 58.2

[0165] As shown in Table 3, the gel strength of Comparative Example 4 is significantly lower than that of Example 1. Figure 7 The gelatinous feeling of the konjac jelly of Comparative Example 4 is obviously not as good as that of the konjac jelly of Example 1.

[0166] (III) The amount of water precipitated is the weight ratio of water precipitated from the jelly gel system. When consumers open the package for consumption, the liquid will flow out. It is a key indicator for measuring the stability of the jelly gel. To further illustrate the water precipitate and storage time of the konjac jelly prepared by the present invention, the konjac jelly of Example 1 and Comparative Example 1 was tested for its water precipitate after 6 months and 12 months, and the situation after 12 months was analyzed. The water precipitate of the konjac jelly of Example 1 and Comparative Example 1 after 6 months is shown in the figure. Figure 8 As shown, the water separation amount of the konjac jelly samples of Example 1 and Comparative Example 1 after 6 months and 12 months is shown in Table 4 below:

[0167] Table 4 Water separation of konjac jelly samples of Example 1 and Comparative Example 1 after 6 and 12 months

[0168]

[0169] The konjac jelly samples of Example 1 and Comparative Example 1 were kept for 12 months. Figure 9 As shown, by comparison, the konjac jelly of the embodiment has a springy and tough taste, normal color, no peculiar smell, and slight liquid precipitation after being kept for 12 months, which meets the requirements of product quality standards; while the konjac jelly of comparative example 1 has a soft and rotten taste after being kept for 12 months, has no elasticity of jelly gel application, has serious water precipitation, turbid liquid, and slight peculiar smell, and the product is no longer suitable for consumption. It can be seen that the preparation method of the present invention can effectively prolong the shelf life of konjac jelly.

[0170] 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 preparation method of a modified composite colloid solution, characterized in that, It includes the following steps: 1) Mixed glue preparation: Mix konjac micro-powder, process water, resistant dextrin and locust bean gum evenly, heat up to 45 - 60 °C, and stir for 15 - 30 minutes to obtain a composite colloid solution; 2) Enzymatic modification: Add pullulanase to the composite colloid solution, keep it warm and stir at 50 - 60 °C for 2 - 4 hours to obtain a modified composite colloid solution; The raw materials of the modified composite colloid solution are composed of the following components by mass percentage: konjac micro-powder 15 - 20%, resistant dextrin 1 - 2%, locust bean gum 0.1 - 1%, pullulanase 0.1 - 0.5%, and the balance is process water; The konjac micro-powder is prepared by the following preparation method: S1. Ultrafine grinding treatment: Ultrafinely grind the crude konjac powder to obtain konjac powder with a particle size D50 below 15.0 μm; S2. Electric pulse treatment: Place the konjac powder after the ultrafine grinding treatment in S1 into a pulsed electric field processor for the tissue shrinkage elasticity strengthening treatment of konjac micro-powder to obtain konjac micro-powder; The parameters of the pulsed electric field processor are: electric field strength 10 - 20 kV / cm, pulse width 5 - 50 μs, pulse frequency 100 - 800 Hz, flow rate 100 - 200 g / min, and pulsed electric field treatment time 10 - 30 min.

2. A modified composite colloid solution, characterized in that, It is prepared by the preparation method of the modified composite colloid solution described in Claim 1.

3. A konjac jelly, characterized in that, It is composed of the following components by mass percentage: modified composite colloid solution 8 - 15%, fruit juice 20 - 30%, syrup 10 - 20%, citric acid 0.1 - 0.5%, calcium lactate 0.1 - 0.5%, potassium chloride 0.05 - 0.15%, potassium sorbate 0.01 - 0.05%, sodium citrate 0.05 - 0.15%, edible essence 0.01 - 0.1%, and the balance is process water; the modified composite colloid solution is the modified composite colloid solution described in Claim 2.

4. The preparation method of the konjac jelly according to claim 3, characterized in that, It includes the following steps: (1) Jelly material liquid preparation: Heat the modified composite colloid solution to above 70 °C, add process water, fruit juice, syrup, citric acid, calcium lactate, potassium chloride, sodium citrate, potassium sorbate and edible essence, heat to 96 ± 2 °C, and stir for 10 - 15 minutes until fully uniform to obtain a jelly material liquid; (2) Homogenization treatment: Treat the jelly material liquid by a two-stage homogenization process to make a semi-finished jelly material liquid; (3) Filtration: Filter the semi-finished jelly material liquid after homogenization treatment through a 200-mesh aperture, keep it warm at a temperature above 70 °C, conduct secondary filtration of the filtered semi-finished jelly material liquid through a 60-mesh aperture, sterilize the semi-finished jelly material liquid after secondary filtration, and then cool and gel to obtain konjac jelly.

5. The preparation method of the konjac jelly according to claim 4, characterized in that, The pressure of the first stage of the two-stage homogenization process is 18 - 22 MPa, and the pressure of the second stage is 3 - 5 MPa.

6. The preparation method of the konjac jelly according to claim 5, characterized in that, The sterilization includes sterilizing the semi-finished jelly material liquid after secondary filtration within 10 minutes; the temperature of the sterilization is 84 - 87 °C, and the time is 7.5 - 8.5 minutes.

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