Enzymolysis acquisition method of seaweed dietary fibers

Abstract

The invention relates to the technical field of seaweed dietary fibers, in particular to a seaweed dietary fiber enzymolysis obtaining method. The seaweed dietary fiber enzymolysis obtaining method comprises the following steps: uniformly mixing seaweed, cane sugar and iron powder, adding water, uniformly mixing and grinding, cooling, preserving heat, heating to room temperature, feeding into a steam explosion tank, introducing saturated steam, performing pressure-maintaining explosion, cooling to room temperature, adjusting the pH value of a system to 3-4, washing, and freeze-drying to obtain pretreated seaweed; adding the pretreated seaweed, phospholipid and cholesterol into water for ultrasonic dispersion, adjusting the pH value of a system to 7.1-7.35, adding a first compound enzyme for enzymolysis, adjusting the pH value of the system to 5.0-6.5, adding a second compound enzyme for enzymolysis, adding a third compound enzyme for enzymolysis, inactivating, and cooling to room temperature to obtain enzymolysis seaweed; centrifuging the enzymolysis seaweed to obtain precipitate and filtrate; washing the precipitate, and freeze-drying to obtain a prefabricated material; and carrying out alcohol precipitation on the filtrate for 5-15 hours by adopting an ethanol water solution, centrifuging, adding the prefabricated material, uniformly mixing, and drying.

Description

Technical Field

[0001] The invention relates to the technical field of seaweed dietary fiber, and in particular to a method for obtaining seaweed dietary fiber by enzymolysis. Background Art

[0002] Dietary fiber is a type of carbohydrate that cannot be digested and absorbed in the human upper digestive tract. It has the edible benefits of promoting intestinal motility, relieving constipation, preventing colon cancer, diabetes, obesity, and reducing cardiovascular diseases. Dietary fiber has more and more physiological functions in preventing obesity and intestinal diseases, regulating and stabilizing blood sugar levels, preventing cardiovascular diseases, scavenging oxygen free radicals, improving the body's immunity, and changing the composition of microbial communities in the intestinal system, and is receiving more and more attention.

[0003] Seaweed is a lower plant that grows in the ocean. As one of the important components of marine life, it not only contains rich nutrients such as protein, vitamins, minerals, but also contains rich dietary fiber. However, for a long time, only a small part of seaweed has been directly consumed.

[0004] To further comprehensively utilize my country's seaweed resources, improve the utilization rate of seaweed, and especially to deeply develop its value has become the current research focus. The most abundant content in seaweed is dietary fiber. At present, the development of dietary fiber functional products using seaweed fiber has become the research direction of comprehensive utilization of kelp. my country's seaweed processing is mainly crude processing, and at least 50% of the active ingredients of seaweed cannot be fully utilized and are used as waste.

[0005] The processing of dietary fiber is not only prone to environmental pollution and low yield, but also significantly reduces the water holding capacity of the obtained dietary fiber. The product does not have good biological activity, which affects its physiological function and needs to be solved urgently. Summary of the invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a method for obtaining seaweed dietary fiber by enzymatic hydrolysis.

[0007] A method for obtaining seaweed dietary fiber by enzymatic hydrolysis, comprising the following steps:

[0008] S1. Mix seaweed, sucrose and iron powder evenly, add water to a water content of 5-15%, mix and grind evenly, cool to -40--50°C, keep warm for 3-6h, raise the room temperature, send to a steam explosion tank, pass saturated steam, maintain the pressure in the tank at 0.8-1.1MPa, keep the pressure for 2-5min before explosion, cool to room temperature, adjust the pH value of the system to 3-4 with citric acid, perform ultrasound for 1-2h, the ultrasound frequency is 5-12kHz, wash with water until the pH value of the system is 6.5-6.8, and freeze-dry to obtain pretreated seaweed;

[0009] S2, adding the pretreated seaweed, phospholipids and cholesterol into water and ultrasonically dispersing for 10-20 minutes, adjusting the pH value of the system to 7.1-7.35, adding the first complex enzyme thereto, performing enzymolysis at 55-65°C for 1-2 hours, adjusting the pH value of the system to 5.0-6.5, adding the second complex enzyme, performing enzymolysis at 40-50°C for 2-6 hours, adding the third complex enzyme, performing enzymolysis at 40-50°C for 1-3 hours, inactivating, and cooling to room temperature to obtain enzymolyzed seaweed;

[0010] The first complex enzyme includes: papain and pectinase, the enzymatic activity of papain is 1000-4000U / g, and the enzymatic activity of pectinase is 8000-12000U / g;

[0011] The second complex enzyme includes: pepsin and xylanase, wherein the enzymatic activity of pepsin is 2000-3000 U / g, and the enzymatic activity of xylanase is 1500-2200 U / g;

[0012] The third complex enzyme includes: bacterial isoamylase and Aspergillus niger protease, wherein the enzyme activity of the bacterial isoamylase is 1000-1500 U / g, and the enzyme activity of the Aspergillus niger protease is 2000-5000 U / g;

[0013] S3, centrifuging the enzymatically hydrolyzed seaweed to obtain a precipitate and a filtrate; washing the precipitate, freeze-drying it to obtain a prefabricated material; using an ethanol aqueous solution to precipitate the filtrate for 5-15 hours, centrifuging it, adding the prefabricated material to mix evenly, and drying it.

[0014] Preferably, in S1, the mass ratio of seaweed, sucrose and iron powder is 50-100:1-5:1-10.

[0015] Preferably, in S1, the particle size of the iron powder is 50-100 μm.

[0016] Among them, seaweed and iron powder are compounded for temperature increase and decrease. Due to the good thermal conductivity of iron powder, the internal and external structures of seaweed can be quickly cooled down or heated to a specified temperature, thereby increasing the stability of subsequent dietary fiber extraction. In the subsequent steam explosion process, the iron powder reacts with high-temperature saturated steam to generate ferrous oxide, which is further combined with oxygen and accompanied by an expansion effect in conjunction with the explosion process, thereby causing the seaweed cell wall to be completely cleaved, thereby facilitating the subsequent enzymatic hydrolysis and effectively increasing the dietary fiber yield.

[0017] Preferably, in S1, after grinding, the temperature is lowered from room temperature to -40 to -50°C at a rate of 1-2°C / min.

[0018] Preferably, in S1, after the temperature is kept warm, the temperature is quickly raised to room temperature at a rate of 5-10°C / min.

[0019] Preferably, in S2, the mass ratio of the pretreated seaweed, phospholipid, cholesterol, the first complex enzyme, the second complex enzyme, and the third complex enzyme is 100:1-5:1-5:5-15:5-15:1-3.

[0020] Preferably, in S2, the ultrasonic dispersion frequency is 3-10 kHz.

[0021] Preferably, in S2, a sodium hydrogen phosphate-citric acid buffer solution with a pH value of 8.0 is used to adjust the pH value of the system to 7.1-7.35.

[0022] Preferably, in S2, the inactivation temperature is 90-96°C.

[0023] Preferably, in S3, the precipitate is washed with deionized water at a temperature of 70-80°C.

[0024] Preferably, in S3, the mass fraction of the ethanol aqueous solution is 92-95%.

[0025] Beneficial effects:

[0026] The present invention realizes the efficient utilization of seaweed resources to prepare dietary fiber. The obtained dietary fiber has high water holding capacity, can effectively inhibit the occurrence of constipation, and while promoting defecation, also has the effect of improving gastrointestinal flora and increasing the activity of dietary fiber.

[0027] The present invention utilizes seaweed and iron powder to increase or decrease the temperature. Since the iron powder has good thermal conductivity, it can promote the rapid cooling or heating of the internal and external structures of the seaweed to a specified temperature, thereby improving the stable yield of subsequent dietary fiber extraction. However, this can easily lead to the destruction of the seaweed fiber structure and affect its biological activity. Therefore, it is further combined with the effect of sucrose to effectively protect the seaweed dietary fiber from damage during the pretreatment process while ensuring the subsequent extraction effect of the dietary fiber, thereby maintaining the stability of the product's biological activity.

[0028] The present invention combines the pretreated seaweed with phospholipids and cholesterol by ultrasonic treatment to form a phospholipid bilayer, which has excellent stability in combination with cholesterol. By adjusting the pH of the system and combining it with the first composite enzyme, a high enzymatic stability can be maintained at a temperature of 55-65°C, and the enzymatic effect is excellent. Further second and third enzymatic hydrolysis can significantly improve the seaweed dietary fiber yield. Experiments have confirmed that after the first and second composite enzyme hydrolysis, the third composite enzyme has the most significant improvement in the water holding capacity of insoluble dietary fiber. Compared with the product that has not undergone the third enzymatic hydrolysis, its water holding capacity can be increased by up to 40.16%, and the effect is significant.

[0029] The invention has simple process, is easy to operate and control, is very suitable for industrial large-scale production, and brings economic benefits to the seaweed industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The figure is a comparison chart of the yield and swelling power of dietary fiber obtained in Example 5 and Comparative Examples 1-3.

[0031] Figure 2 This is a comparison chart of the water holding capacity of dietary fibers obtained in Example 5 and Comparative Examples 1-3.

[0032] Figure 3 It is a comparison chart of the changes in the number of probiotics per gram of wet feces of mice in the blank control group, constipation model group, Example 5 group and Comparative Example 1-3 groups.

[0033] Figure 4 It is a comparison chart of the number and weight of black stool particles excreted within 5 hours by mice in the blank control group, constipation model group, Example 5 group and Comparative Example 1-3 groups. DETAILED DESCRIPTION

[0034] The present invention will be further explained below in conjunction with specific embodiments.

[0035] Example 1

[0036] A method for obtaining seaweed dietary fiber by enzymatic hydrolysis, comprising the following steps:

[0037] S1. 5 kg of seaweed, 0.1 kg of sucrose and 0.1 kg of iron powder with an average particle size of 60 μm were mixed evenly, water was added to a water content of 5%, the mixture was mixed and ground evenly, the temperature was lowered from room temperature to -40°C at a rate of 1°C / min, the temperature was kept for 3 hours, the temperature was quickly raised to room temperature at a rate of 5°C / min, the mixture was sent to a steam explosion tank, saturated steam was introduced, the pressure in the tank was maintained at 0.8 MPa, the pressure was kept for 2 minutes and the mixture was exploded, the temperature was lowered to room temperature, citric acid was used to adjust the pH value of the system to 3-4, ultrasonic treatment was performed for 1 hour, the ultrasonic frequency was 8 kHz, the mixture was washed with water until the pH value of the system was 6.5-6.8, and freeze-dried to obtain the pretreated seaweed;

[0038] S2, adding 10kg of pretreated seaweed, 0.1kg of phospholipids, and 0.1kg of cholesterol to 20kg of water for ultrasonic dispersion for 10min, the ultrasonic frequency is 3kHz, using disodium hydrogen phosphate-citric acid buffer with pH=8.0 to adjust the pH value of the system to 7.1-7.35, adding 0.5kg of the first complex enzyme thereto, enzymolyzing at a temperature of 55°C for 1h, adjusting the pH value of the system to 5.0-6.5, adding 0.5kg of the second complex enzyme, enzymolyzing at a temperature of 40°C for 2h, adding 0.1kg of the third complex enzyme, enzymolyzing at a temperature of 40°C for 1h, inactivating at a temperature of 90°C, and cooling to room temperature to obtain enzymolyzed seaweed;

[0039] The first complex enzyme is composed of papain with an enzyme activity of 1000U / g and pectinase with an enzyme activity of 8000U / g; the second complex enzyme is composed of pepsin with an enzyme activity of 2000U / g and xylanase with an enzyme activity of 1500U / g; the third complex enzyme is composed of bacterial isoamylase with an enzyme activity of 1000U / g and Aspergillus niger protease with an enzyme activity of 2000U / g;

[0040] S3. Centrifuge the enzymatically hydrolyzed seaweed to obtain a precipitate and a filtrate, wash the precipitate three times with deionized water at 70°C, freeze-dry, and obtain a prefabricated material; precipitate the filtrate with 92% ethanol aqueous solution for 5 hours, centrifuge at 8000rpm for 5 minutes, add the prefabricated material, mix well, and dry at 40°C.

[0041] Example 2

[0042] A method for obtaining seaweed dietary fiber by enzymatic hydrolysis, comprising the following steps:

[0043] S1. 10 kg of seaweed, 0.5 kg of sucrose and 1 kg of iron powder with an average particle size of 90 μm were mixed evenly, water was added to a water content of 15%, the mixture was mixed and ground evenly, the temperature was lowered from room temperature to -50°C at a rate of 2°C / min, the temperature was kept for 6 hours, the temperature was quickly raised to room temperature at a rate of 10°C / min, the mixture was sent to a steam explosion tank, saturated steam was introduced, the pressure in the tank was maintained at 1.1 MPa, the pressure was kept for 5 minutes and the mixture was exploded, the temperature was lowered to room temperature, citric acid was used to adjust the pH value of the system to 3-4, ultrasonic treatment was performed for 2 hours, the ultrasonic frequency was 10 kHz, the mixture was washed with water until the pH value of the system was 6.5-6.8, and freeze-dried to obtain the pretreated seaweed;

[0044] S2, adding 10kg of pretreated seaweed, 0.5kg of phospholipids, and 0.5kg of cholesterol to 40kg of water for ultrasonic dispersion for 20min, the ultrasonic frequency is 10kHz, using disodium hydrogen phosphate-citric acid buffer with pH=8.0 to adjust the pH value of the system to 7.1-7.35, adding 1.5kg of the first complex enzyme thereto, enzymolyzing at a temperature of 65°C for 2h, adjusting the pH value of the system to 5.0-6.5, adding 1.5kg of the second complex enzyme, enzymolyzing at a temperature of 50°C for 6h, adding 0.3kg of the third complex enzyme, enzymolyzing at a temperature of 50°C for 3h, inactivating at a temperature of 96°C, and cooling to room temperature to obtain enzymolyzed seaweed;

[0045] The first complex enzyme is composed of papain with an enzyme activity of 4000U / g and pectinase with an enzyme activity of 12000U / g; the second complex enzyme is composed of pepsin with an enzyme activity of 3000U / g and xylanase with an enzyme activity of 2200U / g; the third complex enzyme is composed of bacterial isoamylase with an enzyme activity of 1500U / g and Aspergillus niger protease with an enzyme activity of 5000U / g;

[0046] S3. Centrifuge the enzymatically hydrolyzed seaweed to obtain a precipitate and a filtrate, wash the precipitate with deionized water at 80°C for 5 times, freeze-dry, and obtain a prefabricated material; precipitate the filtrate with 95% ethanol aqueous solution for 15 hours, centrifuge at 8000rpm for 5 minutes, add the prefabricated material, mix well, and dry at 40°C.

[0047] Example 3

[0048] A method for obtaining seaweed dietary fiber by enzymatic hydrolysis, comprising the following steps:

[0049] S1. 7 kg of seaweed, 0.4 kg of sucrose and 0.3 kg of iron powder with an average particle size of 80 μm were mixed evenly, water was added to a water content of 8%, the mixture was mixed and ground evenly, the temperature was lowered from room temperature to -42°C at a rate of 1.8°C / min, the temperature was kept for 5 hours, the temperature was quickly raised to room temperature at a rate of 7°C / min, the mixture was sent to a steam explosion tank, saturated steam was introduced, the pressure in the tank was maintained at 1 MPa, the pressure was kept for 3 minutes and the mixture was exploded, the temperature was lowered to room temperature, citric acid was used to adjust the pH value of the system to 3-4, ultrasonic treatment was performed for 1 hour, the ultrasonic frequency was 6kHz, the mixture was washed with water until the pH value of the system was 6.5-6.8, and freeze-dried to obtain the pretreated seaweed;

[0050] S2, adding 10kg of pretreated seaweed, 0.4kg of phospholipids, and 0.2kg of cholesterol to 34kg of water for ultrasonic dispersion for 12min, the ultrasonic frequency is 9kHz, using disodium hydrogen phosphate-citric acid buffer with pH=8.0 to adjust the pH value of the system to 7.1-7.35, adding 0.8kg of the first complex enzyme thereto, enzymolyzing at a temperature of 62°C for 80min, adjusting the pH value of the system to 5.0-6.5, adding 1.2kg of the second complex enzyme, enzymolyzing at a temperature of 43°C for 5h, adding 0.15kg of the third complex enzyme, enzymolyzing at a temperature of 48°C for 1.5h, inactivating at a temperature of 94°C, and cooling to room temperature to obtain enzymolyzed seaweed;

[0051] The first complex enzyme is composed of papain with an enzyme activity of 2000U / g and pectinase with an enzyme activity of 11000U / g; the second complex enzyme is composed of pepsin with an enzyme activity of 2200U / g and xylanase with an enzyme activity of 2000U / g; the third complex enzyme is composed of bacterial isoamylase with an enzyme activity of 1100U / g and Aspergillus niger protease with an enzyme activity of 4000U / g;

[0052] S3. Centrifuge the enzymatically hydrolyzed seaweed to obtain a precipitate and a filtrate, wash the precipitate with deionized water at 73°C for 4 times, freeze-dry, and obtain a prefabricated material; precipitate the filtrate with 94% ethanol aqueous solution for 8 hours, centrifuge at 8000 rpm for 5 minutes, add the prefabricated material, mix well, and dry at 40°C.

[0053] Example 4

[0054] A method for obtaining seaweed dietary fiber by enzymatic hydrolysis, comprising the following steps:

[0055] S1. 9 kg of seaweed, 0.2 kg of sucrose and 0.7 kg of iron powder with an average particle size of 70 μm were mixed evenly, water was added to a water content of 12%, the mixture was mixed and ground evenly, the temperature was lowered from room temperature to -48°C at a rate of 1.2°C / min, the temperature was kept for 4 hours, the temperature was quickly raised to room temperature at a rate of 9°C / min, the mixture was sent to a steam explosion tank, saturated steam was introduced, the pressure in the tank was maintained at 0.9 MPa, the pressure was kept for 4 minutes and the mixture was exploded, the temperature was lowered to room temperature, citric acid was used to adjust the pH value of the system to 3-4, ultrasonic treatment was performed for 2 hours, the ultrasonic frequency was 12 kHz, the mixture was washed with water until the pH value of the system was 6.5-6.8, and freeze-dried to obtain pretreated seaweed;

[0056] S2, adding 10kg of pretreated seaweed, 0.2kg of phospholipids, and 0.4kg of cholesterol to 26kg of water for ultrasonic dispersion for 18min, the ultrasonic frequency is 6kHz, using disodium hydrogen phosphate-citric acid buffer with pH=8.0 to adjust the pH value of the system to 7.1-7.35, adding 1.2kg of the first complex enzyme thereto, enzymolyzing at a temperature of 58°C for 100min, adjusting the pH value of the system to 5.0-6.5, adding 0.8kg of the second complex enzyme, enzymolyzing at a temperature of 47°C for 3h, adding 0.25kg of the third complex enzyme, enzymolyzing at a temperature of 42°C for 2.5h, inactivating at a temperature of 92°C, and cooling to room temperature to obtain enzymolyzed seaweed;

[0057] The first complex enzyme is composed of papain with an enzyme activity of 3000U / g and pectinase with an enzyme activity of 9000U / g; the second complex enzyme is composed of pepsin with an enzyme activity of 2800U / g and xylanase with an enzyme activity of 1700U / g; the third complex enzyme is composed of bacterial isoamylase with an enzyme activity of 1300U / g and Aspergillus niger protease with an enzyme activity of 3000U / g;

[0058] S3. Centrifuge the enzymatically hydrolyzed seaweed to obtain a precipitate and a filtrate, wash the precipitate with deionized water at 77°C for 4 times, freeze-dry, and obtain a prefabricated material; precipitate the filtrate with 93% ethanol aqueous solution for 12 h, centrifuge at 8000 rpm for 5 min, add the prefabricated material, mix well, and dry at 40°C.

[0059] Example 5

[0060] A method for obtaining seaweed dietary fiber by enzymatic hydrolysis, comprising the following steps:

[0061] S1. 8 kg of seaweed, 0.3 kg of sucrose and 0.5 kg of iron powder with an average particle size of 75 μm were mixed evenly, water was added to a water content of 10%, the mixture was mixed and ground evenly, the temperature was lowered from room temperature to -45°C at a rate of 1.5°C / min, the temperature was kept for 4.5 hours, the temperature was quickly raised to room temperature at a rate of 8°C / min, the mixture was sent to a steam explosion tank, saturated steam was introduced, the pressure in the tank was maintained at 0.95 MPa, the pressure was kept for 3.5 minutes and the mixture was exploded, the temperature was lowered to room temperature, citric acid was used to adjust the pH value of the system to 3-4, ultrasonic treatment was performed for 1 hour, the ultrasonic frequency was 10 kHz, the mixture was washed with water until the pH value of the system was 6.5-6.8, and freeze-dried to obtain the pretreated seaweed;

[0062] S2, adding 10kg of pretreated seaweed, 0.3kg of phospholipids, and 0.3kg of cholesterol to 30kg of water for ultrasonic dispersion for 15min, the ultrasonic frequency is 7.5kHz, using disodium hydrogen phosphate-citric acid buffer with pH=8.0 to adjust the pH value of the system to 7.1-7.35, adding 1kg of the first complex enzyme thereto, enzymolyzing at a temperature of 60°C for 90min, adjusting the pH value of the system to 5.0-6.5, adding 1kg of the second complex enzyme, enzymolyzing at a temperature of 45°C for 4h, adding 0.2kg of the third complex enzyme, enzymolyzing at a temperature of 45°C for 2h, inactivating at a temperature of 95°C, and cooling to room temperature to obtain enzymolyzed seaweed;

[0063] The first complex enzyme is composed of papain with an enzyme activity of 2500U / g and pectinase with an enzyme activity of 10000U / g; the second complex enzyme is composed of pepsin with an enzyme activity of 2500U / g and xylanase with an enzyme activity of 1800U / g; the third complex enzyme is composed of bacterial isoamylase with an enzyme activity of 1200U / g and Aspergillus niger protease with an enzyme activity of 3500U / g;

[0064] S3. Centrifuge the enzymatically hydrolyzed seaweed to obtain a precipitate and a filtrate, wash the precipitate four times with deionized water at 75°C, freeze-dry, and obtain a prefabricated material; precipitate the filtrate with 94% ethanol aqueous solution for 10 hours, centrifuge at 8000rpm for 5 minutes, add the prefabricated material, mix well, and dry at 40°C.

[0065] Comparative Example 1

[0066] A method for obtaining seaweed dietary fiber by enzymatic hydrolysis, comprising the following steps:

[0067] S1. 8 kg of seaweed and 0.5 kg of iron powder with an average particle size of 75 μm were mixed evenly, water was added to a water content of 10%, the mixture was mixed and ground evenly, the temperature was lowered from room temperature to -45°C at a rate of 1.5°C / min, the temperature was kept for 4.5 hours, the temperature was quickly raised to room temperature at a rate of 8°C / min, the mixture was sent to a steam explosion tank, saturated steam was introduced, the pressure in the tank was maintained at 0.95 MPa, the pressure was kept for 3.5 minutes and the mixture was exploded, the temperature was lowered to room temperature, citric acid was used to adjust the pH value of the system to 3-4, ultrasonic treatment was performed for 1 hour, the ultrasonic frequency was 10 kHz, the mixture was washed with water until the pH value of the system was 6.5-6.8, and freeze-dried to obtain the pretreated seaweed;

[0068] S2, adding 10kg of pretreated seaweed, 0.3kg of phospholipids, and 0.3kg of cholesterol to 30kg of water for ultrasonic dispersion for 15min, the ultrasonic frequency is 7.5kHz, using disodium hydrogen phosphate-citric acid buffer with pH=8.0 to adjust the pH value of the system to 7.1-7.35, adding 1kg of the first complex enzyme thereto, enzymolyzing at a temperature of 60°C for 90min, adjusting the pH value of the system to 5.0-6.5, adding 1kg of the second complex enzyme, enzymolyzing at a temperature of 45°C for 4h, adding 0.2kg of the third complex enzyme, enzymolyzing at a temperature of 45°C for 2h, inactivating at a temperature of 95°C, and cooling to room temperature to obtain enzymolyzed seaweed;

[0069] The first complex enzyme is composed of papain with an enzyme activity of 2500U / g and pectinase with an enzyme activity of 10000U / g; the second complex enzyme is composed of pepsin with an enzyme activity of 2500U / g and xylanase with an enzyme activity of 1800U / g; the third complex enzyme is composed of bacterial isoamylase with an enzyme activity of 1200U / g and Aspergillus niger protease with an enzyme activity of 3500U / g;

[0070] S3. Centrifuge the enzymatically hydrolyzed seaweed to obtain a precipitate and a filtrate, wash the precipitate four times with deionized water at 75°C, freeze-dry, and obtain a prefabricated material; precipitate the filtrate with 94% ethanol aqueous solution for 10 hours, centrifuge at 8000rpm for 5 minutes, add the prefabricated material, mix well, and dry at 40°C.

[0071] Comparative Example 2

[0072] A method for obtaining seaweed dietary fiber by enzymatic hydrolysis, comprising the following steps:

[0073] S1. 8 kg of seaweed, 0.3 kg of sucrose and 0.5 kg of iron powder with an average particle size of 75 μm were mixed evenly, water was added to a water content of 10%, the mixture was mixed and ground evenly, the temperature was lowered from room temperature to -45°C at a rate of 1.5°C / min, the temperature was kept for 4.5 hours, the temperature was quickly raised to room temperature at a rate of 8°C / min, the mixture was sent to a steam explosion tank, saturated steam was introduced, the pressure in the tank was maintained at 0.95 MPa, the pressure was kept for 3.5 minutes and the mixture was exploded, the temperature was lowered to room temperature, citric acid was used to adjust the pH value of the system to 3-4, ultrasonic treatment was performed for 1 hour, the ultrasonic frequency was 10 kHz, the mixture was washed with water until the pH value of the system was 6.5-6.8, and freeze-dried to obtain the pretreated seaweed;

[0074] S2, adding 10kg of pretreated seaweed to 30kg of water and ultrasonically dispersing for 15min, the ultrasonic frequency is 7.5kHz, using disodium hydrogen phosphate-citric acid buffer with pH=8.0 to adjust the pH value of the system to 7.1-7.35, adding 1kg of the first complex enzyme thereto, enzymolyzing at a temperature of 60°C for 90min, adjusting the pH value of the system to 5.0-6.5, adding 1kg of the second complex enzyme, 0.3kg of phospholipids, and 0.3kg of cholesterol to mix evenly, enzymolyzing at a temperature of 45°C for 4h, adding 0.2kg of the third complex enzyme, enzymolyzing at a temperature of 45°C for 2h, inactivating at a temperature of 95°C, and cooling to room temperature to obtain enzymolyzed seaweed;

[0075] The first complex enzyme is composed of papain with an enzyme activity of 2500U / g and pectinase with an enzyme activity of 10000U / g; the second complex enzyme is composed of pepsin with an enzyme activity of 2500U / g and xylanase with an enzyme activity of 1800U / g; the third complex enzyme is composed of bacterial isoamylase with an enzyme activity of 1200U / g and Aspergillus niger protease with an enzyme activity of 3500U / g;

[0076] S3. Centrifuge the enzymatically hydrolyzed seaweed to obtain a precipitate and a filtrate, wash the precipitate four times with deionized water at 75°C, freeze-dry, and obtain a prefabricated material; precipitate the filtrate with 94% ethanol aqueous solution for 10 hours, centrifuge at 8000rpm for 5 minutes, add the prefabricated material, mix well, and dry at 40°C.

[0077] Comparative Example 3

[0078] A method for obtaining seaweed dietary fiber by enzymatic hydrolysis, comprising the following steps:

[0079] S1. 8 kg of seaweed, 0.3 kg of sucrose and 0.5 kg of iron powder with an average particle size of 75 μm were mixed evenly, water was added to a water content of 10%, the mixture was mixed and ground evenly, the temperature was lowered from room temperature to -45°C at a rate of 1.5°C / min, the temperature was kept for 4.5 hours, the temperature was quickly raised to room temperature at a rate of 8°C / min, the mixture was sent to a steam explosion tank, saturated steam was introduced, the pressure in the tank was maintained at 0.95 MPa, the pressure was kept for 3.5 minutes and the mixture was exploded, the temperature was lowered to room temperature, citric acid was used to adjust the pH value of the system to 3-4, ultrasonic treatment was performed for 1 hour, the ultrasonic frequency was 10 kHz, the mixture was washed with water until the pH value of the system was 6.5-6.8, and freeze-dried to obtain the pretreated seaweed;

[0080] S2, adding 10kg of pretreated seaweed, 0.3kg of phospholipids, and 0.3kg of cholesterol to 30kg of water for ultrasonic dispersion for 15min, the ultrasonic frequency is 7.5kHz, using disodium hydrogen phosphate-citric acid buffer with pH=8.0 to adjust the pH value of the system to 7.1-7.35, adding 1kg of the first complex enzyme thereto, enzymolyzing at a temperature of 60°C for 90min, adjusting the pH value of the system to 5.0-6.5, adding 1.2kg of the second complex enzyme, enzymolyzing at a temperature of 45°C for 6h, inactivating at a temperature of 95°C, and cooling to room temperature to obtain enzymolyzed seaweed;

[0081] The first complex enzyme is composed of papain with an enzyme activity of 2500U / g and pectinase with an enzyme activity of 10000U / g; the second complex enzyme is composed of pepsin with an enzyme activity of 2500U / g and xylanase with an enzyme activity of 1800U / g;

[0082] S3. Centrifuge the enzymatically hydrolyzed seaweed to obtain a precipitate and a filtrate, wash the precipitate four times with deionized water at 75°C, freeze-dry, and obtain a prefabricated material; precipitate the filtrate with 94% ethanol aqueous solution for 10 hours, centrifuge at 8000rpm for 5 minutes, add the prefabricated material, mix well, and dry at 40°C.

[0083] The physicochemical properties of the seaweed dietary fibers obtained in Example 5 and Comparative Examples 1-3 were tested as follows:

[0084] (1) Determine the mass of seaweed dietary fiber obtained in each group and calculate the seaweed dietary fiber yield of each group.

[0085] Dietary fiber yield = total dietary fiber content of each group ÷ dry weight of seaweed × 100%

[0086] (2) Weigh 1.00 g of each group of seaweed dietary fiber powder into a measuring cylinder, read the milliliters of the fiber powder, and then estimate the expansion power of the seaweed dietary fiber. Add an appropriate amount of 20°C water and shake well. Place at 20°C for 24 hours and read the milliliters of the fiber material in the measuring cylinder after it absorbs water and expands.

[0087] Swelling power (mL / g) = (volume of seaweed dietary fiber after swelling with water - volume of dry seaweed dietary fiber powder) ÷ dry weight of sample × 100%

[0088] (3) Weigh 1.00 g of seaweed dietary fiber powder into a beaker, add an appropriate amount of 20°C water, shake well, and soak at 20°C for 1 hour. Pour the water-saturated fiber onto a filter paper funnel and filter. After the water has dripped dry, transfer all the fiber bound to water to a watch glass and weigh it.

[0089] Water holding capacity = (sample wet weight - sample dry weight) ÷ sample dry weight × 100%

[0090] like Figure 1 and Figure 2 As shown, the yield, swelling capacity, water holding capacity and soluble dietary fiber content of the seaweed dietary fiber obtained in Example 5 were the highest, which were better than those in Comparative Examples 1-3 (P < 0.05).

[0091] The seaweed dietary fibers obtained in Example 5 and Comparative Examples 1-3 were used to conduct a comparative test on mice, with healthy and clean grade Kunming mice (male, weighing 18-22 g) as the test subjects.

[0092] Prepare ink: weigh 100 g of gum arabic, add 800 mL of water, boil until the solution becomes transparent, add 50 g of powdered activated carbon, boil 3 times, add water to make up to 1000 mL after the solution cools, store in a refrigerator at 4°C, and shake well before use.

[0093] The mice were randomly divided into a blank control group, a constipation model group, an example 5 group, a comparative example 1 group, a comparative example 2 group, and a comparative example 3 group. Before the test, 0.1-0.4 g of feces of mice in each group was aseptically taken and weighed, and then each group was gavaged once a day, the blank control group and the constipation model group used 0.2 mL / 10 g BW of distilled water, the example 5 group used the seaweed dietary fiber obtained in example 5 to be gavaged at 0.4 g / kg BW, the comparative example 1 group used the seaweed dietary fiber obtained in comparative example 1 to be gavaged at 0.4 g / kg BW, the comparative example 2 group used the seaweed dietary fiber obtained in comparative example 2 to be gavaged at 0.4 g / kg BW, and the comparative example 3 group used the seaweed dietary fiber obtained in comparative example 3 to be gavaged at 0.4 g / kg BW.

[0094] After 14 days of intragastric administration, 0.1-0.4 g of feces from each group of mice were collected and weighed aseptically on the 14th day. The feces of mice were placed in a dry sterilized small test tube, and the sterilized diluent was added to dilute the feces 10 times in series. The appropriate dilution was selected and inoculated on each culture medium. After cultivation, the number of probiotics (Bifidobacterium, Lactobacillus) per gram of wet feces was calculated, and the logarithm was taken for statistical processing.

[0095] Then, mice in each group were fasted for 16 hours, with free access to water. The constipation model group, Example 5 group, and Comparative Example 1-3 groups were gavaged with 0.50 g / L compound diphenoxylate (10 mg / kg BW), while the blank control group was given water. After 30 minutes, the Example 5 group and Comparative Example 1-3 groups were gavaged with ink + corresponding dietary fiber, while the constipation model group and the blank control group were gavaged with ink only.

[0096] like Figure 3 As shown, after 7 days of intragastric administration, the probiotics (Bifidobacterium and Lactobacillus) in the intestines of mice in Example 5 and Comparative Examples 1-3 increased, and the probiotics in the intestines of mice in Example 5 increased the most, which was better than that in Comparative Examples 1-3 (P < 0.05).

[0097] like Figure 4 As shown, the number and weight of black stool particles excreted within 5 hours by mice in Example 5 and Comparative Example 1-3 groups were better than those in the constipation model group (P < 0.05), confirming that dietary fiber can effectively improve intestinal constipation; and the number and weight of black stool particles excreted within 5 hours by mice in Example 5 group were better than those in Comparative Example 1-3 groups (P < 0.05), and even exceeded those of the blank control group.

[0098] The applicant believes that this is because the present invention uses seaweed and iron powder to compound and raise and lower the temperature. Since the iron powder has a good thermal conductivity, it can promote the internal and external structures of the seaweed to quickly cool down or heat up to a specified temperature, thereby improving the stable yield of subsequent dietary fiber extraction. However, this can easily lead to the destruction of the seaweed fiber structure and affect its biological activity. Therefore, it is further combined with sucrose to effectively protect the seaweed dietary fiber from low temperature damage on the basis of ensuring the subsequent extraction effect of dietary fiber, and the product biological activity has extremely high stability. At the same time, the present invention will pre-treat seaweed with phospholipids and cholesterol by ultrasound, and the phospholipid bilayer formed has excellent stability in combination with cholesterol. By adjusting the system pH and compounding with the first composite enzyme, a high enzymatic stability can be maintained at a temperature of 55-65°C, and the enzymatic effect is excellent. Further enzymatic hydrolysis for the second and third times can significantly improve the seaweed dietary fiber yield. It has been confirmed by experiments that after the first and second composite enzyme hydrolysis, the third composite enzyme has the most significant improvement in the water holding capacity of insoluble dietary fiber. Compared with the product that has not undergone the third enzymatic hydrolysis, its water holding capacity has increased by more than 40.16%, and the effect is remarkable.

[0099] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for obtaining seaweed dietary fiber by enzymatic hydrolysis, characterized in that: The steps include: S1. Mix seaweed, sucrose and iron powder evenly, add water to a water content of 5-15%, mix and grind evenly, cool to -40--50°C, keep warm for 3-6h, raise the room temperature, send to a steam explosion tank, pass saturated steam, maintain the pressure in the tank at 0.8-1.1MPa, keep the pressure for 2-5min before explosion, cool to room temperature, adjust the pH value of the system to 3-4 with citric acid, perform ultrasound for 1-2h, the ultrasound frequency is 5-12kHz, wash with water until the pH value of the system is 6.5-6.8, and freeze-dry to obtain pretreated seaweed; S2, adding the pretreated seaweed, phospholipids and cholesterol into water and ultrasonically dispersing for 10-20 minutes, adjusting the pH value of the system to 7.1-7.35, adding the first complex enzyme thereto, performing enzymolysis at 55-65°C for 1-2 hours, adjusting the pH value of the system to 5.0-6.5, adding the second complex enzyme, performing enzymolysis at 40-50°C for 2-6 hours, adding the third complex enzyme, performing enzymolysis at 40-50°C for 1-3 hours, inactivating, and cooling to room temperature to obtain enzymolyzed seaweed; The first complex enzyme includes: papain and pectinase, the enzymatic activity of papain is 1000-4000U / g, and the enzymatic activity of pectinase is 8000-12000U / g; The second complex enzyme includes: pepsin and xylanase, wherein the enzymatic activity of pepsin is 2000-3000 U / g, and the enzymatic activity of xylanase is 1500-2200 U / g; The third complex enzyme includes: bacterial isoamylase and Aspergillus niger protease, wherein the enzyme activity of the bacterial isoamylase is 1000-1500 U / g, and the enzyme activity of the Aspergillus niger protease is 2000-5000 U / g; S3, centrifuging the enzymatically hydrolyzed seaweed to obtain a precipitate and a filtrate; washing the precipitate, freeze-drying it to obtain a prefabricated material; using an ethanol aqueous solution to precipitate the filtrate for 5-15 hours, centrifuging it, adding the prefabricated material to mix evenly, and drying it.

2. The method for obtaining seaweed dietary fiber by enzymatic hydrolysis according to claim 1, characterized in that: In S1, the mass ratio of seaweed, sucrose and iron powder is 50-100:1-5:1-10.

3. The method for obtaining seaweed dietary fiber by enzymatic hydrolysis according to claim 1, characterized in that: In S1, the particle size of the iron powder is 50-100 μm.

4. The method for obtaining seaweed dietary fiber by enzymatic hydrolysis according to claim 1, characterized in that: In S1, after keeping warm, the temperature is quickly raised to room temperature at a rate of 5-10°C / min.

5. The method for obtaining seaweed dietary fiber by enzymatic hydrolysis according to claim 1, characterized in that: In S2, the mass ratio of the pretreated seaweed, phospholipid, cholesterol, the first complex enzyme, the second complex enzyme, and the third complex enzyme is 100:1-5:1-5:5-15:5-15:1-3.

6. The method for obtaining seaweed dietary fiber by enzymatic hydrolysis according to claim 1, characterized in that: In S2, the ultrasonic dispersion frequency is 3-10 kHz.

7. The method for obtaining seaweed dietary fiber by enzymatic hydrolysis according to claim 1, characterized in that: In S2, disodium hydrogen phosphate-citric acid buffer with pH=8.0 is used to adjust the pH value of the system to 7.1-7.

35.

8. The method for obtaining seaweed dietary fiber by enzymatic hydrolysis according to claim 1, characterized in that: In S2, the inactivation temperature is 90-96°C.

9. The method for obtaining seaweed dietary fiber by enzymatic hydrolysis according to claim 1, characterized in that: In S3, the precipitate is washed with deionized water at a temperature of 70-80°C.

10. The method for obtaining seaweed dietary fiber by enzymatic hydrolysis according to claim 1, characterized in that: In S3, the mass fraction of the ethanol aqueous solution is 92-95%.

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