CN117179322A - Method for preparing dietary fiber by utilizing sea buckthorn pomace solid state fermentation - Google Patents

Abstract

The invention discloses a method for preparing dietary fiber by solid-state fermentation of sea buckthorn pomace. The method includes the following steps: processing sea buckthorn pomace into sea buckthorn pomace pulp; adding cellulase, pectinase, and xylanase to the sea buckthorn pomace pulp. Carbohydrase and β-glucanase are used for ultrasonic enzymatic hydrolysis; the enzymatically hydrolyzed sea buckthorn pomace slurry is used as a substrate, and fermentation bacteria are inoculated for fermentation treatment; the fermented sea buckthorn pomace slurry is dried, ground, and then added with distilled water for ultrasound Extract, filter it under reduced pressure after extraction, collect the filter residue and filtrate; concentrate the filtrate, and then add 95% ethanol for ultrasonic treatment to obtain water-soluble sea buckthorn pomace dietary fiber; add the above filter residue to distilled water, and then place it in a 110°C water bath for 1 hour After filtering, water-insoluble sea buckthorn pomace dietary fiber is obtained. This method prepares high-quality seabuckthorn pomace dietary fiber by modifying the dietary fiber of seabuckthorn pomace, turns waste into treasure, and realizes the comprehensive utilization of by-products of seabuckthorn pomace.

Description

A method for preparing dietary fiber by solid-state fermentation of sea buckthorn pomace

Technical field

The invention relates to the technical field of sea buckthorn processing, and specifically relates to a method for preparing dietary fiber by solid-state fermentation of sea buckthorn pomace.

Background technique

Hippophae rhamnoides L., also known as vinegar willow, yellow acid thorn, acid thorn willow, etc., is a wild plant of the genus Seabuckthorn in the family Elaeaceae. Seabuckthorn is rich in bioactive substances such as polyphenols, flavonoids, organic acids, and vitamins, and has physiological effects such as enhancing immunity, eliminating fatigue, and protecting the digestive system. Seabuckthorn has both medicinal and edible properties, and the development of seabuckthorn resources is increasing day by day. At present, technological research on sea buckthorn products focuses on the technological development of sea buckthorn fruit powder, pulp, and fruit oil products. However, there is insufficient research on the development and utilization of processing by-products such as pomace and fruit leaves, making it impossible to achieve comprehensive utilization of sea buckthorn resources.

The ingredients in the pomace of sea buckthorn were analyzed and found to contain more than 50% dietary fiber, which is higher than that of ordinary fruits and is an ideal source of dietary fiber. Dietary fiber (DF) has the effect of preventing and treating coronary heart disease, colon cancer, obesity, diabetes and other diseases. It is one of the main ingredients of many low-calorie and low-cholesterol health foods. Dietary fiber can be divided into soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) based on different solubility. Among them, the content of soluble dietary fiber is an important indicator for measuring the physiological activity of dietary fiber. Therefore, increasing the content of soluble dietary fiber in dietary fiber is of great significance to improving the quality of its products.

Contents of the invention

In order to solve the above problems, the present invention provides a method for preparing dietary fiber by solid-state fermentation of sea buckthorn pomace. By modifying the dietary fiber of sea buckthorn pomace, high-quality sea buckthorn pomace dietary fiber is prepared, turning waste into treasure, and realizing sea buckthorn pomace dietary fiber. Comprehensive utilization of pomace by-products.

The embodiment of the present invention proposes a method for preparing dietary fiber by solid-state fermentation of sea buckthorn pomace, which includes the following steps:

(1) After pre-processing the sea buckthorn pomace, add distilled water and mix according to the material to liquid mass ratio of 1:20, adjust the pH to 4.0, and obtain the sea buckthorn pomace slurry;

(2) Add 1.0% cellulase, 1.0% pectinase, 0.2% xylanase and 0.2% β-glucanase by mass fraction to the sea buckthorn pomace slurry, and perform ultrasonic enzymatic hydrolysis for 30 minutes to 1 hour. The temperature is 55℃, the ultrasonic power is 250W, the enzyme is inactivated at high temperature, and then cooled to room temperature;

(3) Use the sea buckthorn pulp after enzymatic hydrolysis in step (2) as a substrate, inoculate fermentation bacteria for fermentation treatment, the fermentation temperature is 37°C, the pH is 4.5, and the fermentation time is 20 hours;

(4) Dry and grind the sea buckthorn pulp after fermentation in step (3), then add distilled water according to the material-to-liquid mass ratio of 1:20, and conduct ultrasonic extraction for 30 minutes at a temperature of 70°C with an ultrasonic power of 250W. Then filter it under reduced pressure to collect the filter residue and filtrate;

(5) Concentrate the filtrate in step (4), and then add 95% ethanol of 1:10 to the concentrated liquid in a volume ratio. After ultrasonic for 2 hours, let it stand for 8 hours. The ultrasonic power is 250W. Discard the supernatant and prepare The concentrated precipitate is obtained and vacuum freeze-dried to prepare water-soluble sea buckthorn pomace dietary fiber;

(6) Add distilled water to the filter residue in step (4) according to the material-to-liquid mass ratio of 1:20. After mixing, adjust the pH to 4.0, then place it in a 110°C water bath for 1 hour and then filter. The filter residue is vacuum freeze-dried to obtain water-insoluble water. Sea buckthorn pomace dietary fiber.

According to an embodiment of the present invention, there is a method for preparing dietary fiber by solid-state fermentation of sea buckthorn pomace. This method uses a combination of enzymatic hydrolysis and solid-state fermentation to modify the dietary fiber of sea buckthorn pomace to prepare high-quality sea buckthorn pomace dietary fiber. Waste is turned into treasure, realizing the comprehensive utilization of by-products of sea buckthorn pomace. The preparation process is simple, and no toxic and harmful substances are produced during the processing. It can not only retain the biological activity of the dietary fiber of sea buckthorn pomace to the maximum extent, but also have high security.

Optionally, the fermentation bacteria are 1:1 Streptococcus thermophilus and Lactobacillus bulgaricus.

Optionally, the inoculum amount of the fermentation bacteria is 3.5% of the mass fraction of sea buckthorn pomace slurry.

Alternatively, the cellulase enzyme activity is 40,000 U/g, the pectinase activity is 80,000 U/g, the xylanase activity is 40,000 U/g, and the β-glucanase activity is 10,000 U/g.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of the drawings

Figure 1 is a comparison chart of SDF and IDF contents according to the embodiments of the present invention and comparative examples;

Figure 2 is a comparative chart of antioxidant activity according to the embodiments of the present invention and comparative examples.

Detailed ways

The technical solutions of the present invention are illustrated below through specific examples. It should be understood that the mention of one or more method steps in the present invention does not exclude the existence of other method steps before and after the combination step or that other method steps can be inserted between these explicitly mentioned steps; it should also be understood that these The examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. Moreover, unless otherwise stated, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of each method step or limit the scope of the present invention. Changes or adjustments in their relative relationships are not intended to limit the scope of the present invention. If there is no substantial change in the technical content, it shall also be deemed to be within the practicable scope of the present invention.

In order to better understand the above technical solutions, exemplary embodiments of the present invention are described in more detail below. While exemplary embodiments of the present invention are shown, it is to be understood that the invention may be embodied in various forms and is not limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a thorough understanding of the invention, and to fully convey the scope of the invention to those skilled in the art.

The test materials used in this invention are all common commercial products and can be purchased in the market.

The present invention will be described below with reference to specific embodiments. It should be noted that these embodiments are only illustrative and do not limit the present invention in any way.

Example 1

(1) Raw material pretreatment: dry, crush and pass the impurity-removed pomace through an 80-mesh sieve. Mix the pomace and distilled water according to the material-to-liquid mass ratio of 1:20, adjust the pH to 4.0, and prepare the sea buckthorn pomace slurry for later use.

(2) Ultrasonic enzymatic hydrolysis: Add 1.0% cellulase, 1.0% pectinase, 0.2% xylanase, and 0.2% β-glucanase according to the mass fraction of the sea buckthorn pomace pulp prepared in step (1). , enzymatic hydrolysis in an ultrasound-assisted environment, the enzymatic hydrolysis reaction time is 1 hour, the enzymatic hydrolysis temperature is 55°C, and the ultrasonic power is 250W; the enzyme is inactivated at high temperature and cooled to room temperature. Among them, the cellulase enzyme activity is 40000U/g, the pectinase activity is 80000U/g, the xylanase activity is 40000U/g, and the β-glucanase activity is 10000U/g.

(3) Solid-state fermentation: Use the sea buckthorn pulp after enzymatic hydrolysis in step (2) as the substrate, and inoculate 1:1 Streptococcus thermophilus and Lactobacillus bulgaricus. The total inoculation amount is 3.5% of the mass fraction of the sea buckthorn pulp. The fermentation temperature is 37°C, the pH is 4.5, and the fermentation time is 20 hours.

(4) Extract dietary fiber: Dry the sea buckthorn pomace slurry after fermentation in step (3) at 55°C and then grind it, then add distilled water according to the material to liquid mass ratio of 1:20, and use ultrasonic power in a temperature environment of 70°C. 250W, ultrasonic extraction for 30 minutes. After extraction, filter it under reduced pressure and collect the filter residue and filtrate for later use.

(5) Preparation of water-soluble sea buckthorn pomace dietary fiber: Concentrate the filtrate of step (4) by rotary distillation, and then add 95% ethanol of 1:10 to the concentrated liquid in a volume ratio, and use an ultrasonic power of 250W , after ultrasonic for 2 hours, let it stand for 8 hours, discard the supernatant, and obtain a concentrated precipitate, which is then vacuum freeze-dried to obtain water-soluble sea buckthorn pomace dietary fiber.

(6) Preparation of water-insoluble sea buckthorn pomace dietary fiber: Add the filter residue prepared in step (4) to distilled water at a material-to-liquid mass ratio of 1:20, mix evenly, adjust the pH to 4.0, and then place it in a 110°C water bath for 1 hour. Filter, and vacuum freeze-dry the filter residue to prepare water-insoluble sea buckthorn pomace dietary fiber.

Example 2

(1) Raw material pretreatment: dry, crush and pass the impurity-removed pomace through an 80-mesh sieve. Mix the pomace and distilled water according to the material-to-liquid mass ratio of 1:20, adjust the pH to 4.0, and prepare the sea buckthorn pomace slurry for later use.

(2) Ultrasonic enzymatic hydrolysis: Add 1.0% cellulase, 1.0% pectinase, 0.2% xylanase, and 0.2% β-glucanase according to the mass fraction of the sea buckthorn pomace pulp prepared in step (1). , enzymatic hydrolysis in an ultrasound-assisted environment, the enzymatic hydrolysis reaction time is 1 hour, the enzymatic hydrolysis temperature is 55°C, and the ultrasonic power is 250W; the enzyme is inactivated at high temperature and cooled to room temperature. Among them, the cellulase enzyme activity is 40000U/g, the pectinase activity is 80000U/g, the xylanase activity is 40000U/g, and the β-glucanase activity is 10000U/g.

(3) Solid-state fermentation: Use the enzymatically hydrolyzed seabuckthorn pomace slurry in step (2) as the substrate, inoculate yeast, and set the mass fraction of seabuckthorn pomace slurry to 3.5%. The fermentation temperature is 37°C, the pH is 4.5, and the fermentation time is 20 hours. .

(4) Extract dietary fiber: Dry the sea buckthorn pomace slurry after fermentation in step (3) at 55°C and then grind it, then add distilled water according to the material to liquid mass ratio of 1:20, and use ultrasonic power in a temperature environment of 70°C. 250W, ultrasonic extraction for 30 minutes. After extraction, filter it under reduced pressure and collect the filter residue and filtrate for later use.

(5) Preparation of water-soluble sea buckthorn pomace dietary fiber: Concentrate the filtrate of step (4) by rotary distillation, and then add 95% ethanol of 1:10 to the concentrated liquid in a volume ratio, and use an ultrasonic power of 250W , after ultrasonic for 2 hours, let it stand for 8 hours, discard the supernatant, and obtain a concentrated precipitate, which is then vacuum freeze-dried to obtain water-soluble sea buckthorn pomace dietary fiber.

(6) Preparation of water-insoluble sea buckthorn pomace dietary fiber: Add the filter residue prepared in step (4) to distilled water at a material-to-liquid mass ratio of 1:20, mix evenly, adjust the pH to 4.0, and then place it in a 110°C water bath for 1 hour. Filter, and vacuum freeze-dry the filter residue to prepare water-insoluble sea buckthorn pomace dietary fiber.

Comparative ratio

(1) Raw material pretreatment: dry, crush and pass the impurity-removed pomace through an 80-mesh sieve. Mix the pomace and distilled water according to the material-to-liquid mass ratio of 1:20, adjust the pH to 4.0, and prepare the sea buckthorn pomace slurry for later use.

(2) Ultrasonic enzymatic hydrolysis: Add 1.0% cellulase, 1.0% pectinase, 0.2% xylanase, and 0.2% β-glucanase according to the mass fraction of the sea buckthorn pomace pulp prepared in step (1). , enzymatic hydrolysis in an ultrasound-assisted environment, the enzymatic hydrolysis reaction time is 1 hour, the enzymatic hydrolysis temperature is 55°C, and the ultrasonic power is 250W; the enzyme is inactivated at high temperature and cooled to room temperature. Among them, the cellulase enzyme activity is 40000U/g, the pectinase activity is 80000U/g, the xylanase activity is 40000U/g, and the β-glucanase activity is 10000U/g.

(3) Extract dietary fiber: filter the sea buckthorn pomace pulp after ultrasonic enzymatic hydrolysis in step (2) through vacuum filtration, collect the filter residue and filtrate, and set aside.

(4) Preparation of water-soluble sea buckthorn pomace dietary fiber: Concentrate the filtrate of step (3) by rotary distillation, and then add 95% ethanol of 1:10 to the concentrated liquid in a volume ratio, and use an ultrasonic power of 250W , after ultrasonic for 2 hours, let it stand for 8 hours, discard the supernatant, and obtain a concentrated precipitate, which is then vacuum freeze-dried to obtain water-soluble sea buckthorn pomace dietary fiber.

(5) Preparation of water-insoluble sea buckthorn pomace dietary fiber: Add the filter residue prepared in step (3) to distilled water at a material-to-liquid mass ratio of 1:20, mix evenly, adjust the pH to 4.0, and then place it in a 110°C water bath for 1 hour. Filter, and vacuum freeze-dry the filter residue to prepare water-insoluble sea buckthorn pomace dietary fiber.

Test example

Conduct performance tests on the products obtained in Example 1, Example 2, and Comparative Examples.

The results are shown in Figure 1. Comparing the Examples and Comparative Examples, it can be seen that the combination of ultrasonic enzymatic hydrolysis and solid-state fermentation can increase the soluble dietary fiber content of sea buckthorn pomace, and during solid-state fermentation, it can be seen from Comparing Example 1 and Example 2 that, Fermentation treatment using Streptococcus thermophilus and Lactobacillus bulgaricus can further increase the soluble dietary fiber content of sea buckthorn pomace.

The dietary fiber obtained in Example 1, Example 2 and Comparative Example was subjected to a DPPH free radical scavenging experiment, an ABTS free radical scavenging experiment, and a hydroxyl radical scavenging experiment.

(1) DPPH free radical scavenging experiment: Mix sample solutions of different concentrations with an equal volume of 0.2 mmol/L DPPH ethanol solution, react in the dark at room temperature for 30 minutes, measure the absorbance value ( _Sample A) at a wavelength of 517 nm, and replace DPPH with an equal amount of ethanol. The ethanol solution was used to measure the corresponding absorbance value (A _blank ), and an equal amount of distilled water was used instead of the sample solution to measure the corresponding absorbance value (A _control ). The DPPH free radical scavenging rate was calculated using the following formula:

Clearance rate (%) = [1-(A _sample -A _blank )/A _control ]×100;

(2) ABTS free radical scavenging experiment: Mix 5mL 7mmol/L ABTS solution and 88mL 40mmol/L potassium persulfate solution, store in the dark at room temperature for 12 hours, dilute with ethanol to an absorbance value of 0.7±0.02 at 734nm, and prepare ABTS reagent. Mix 0.4 mL sample solutions of different concentrations with 3.6 mL ABTS reagent, react at room temperature for 6 minutes in the dark, and measure the absorbance value at a wavelength of 734 nm ( _sample B). Use an equal amount of ethanol instead of the ABTS reagent to measure the corresponding absorbance value ( _blank B). An equal amount of distilled water was used instead of the sample solution to measure the corresponding absorbance value (B _control ) and calculate the ABTS free radical scavenging rate. The formula is as follows:

Clearance rate (%) = [1-(B _sample -B _blank )/B _control ]×100;

(3) Hydroxy radical scavenging experiment: Add 0.5 mL 9mmol/L ferrous sulfate solution, 1 mL 9mmol/L salicylic acid ethanol solution, 1 mL 4.4mmol/L hydrogen peroxide and 2 m L to 1 mL sample solutions of different concentrations. L distilled water, mix well and react in a 37°C water bath for 30 minutes. Measure the absorbance value at a wavelength of 510 nm (C _sample ). Use an equal amount of ethanol instead of the salicylic acid ethanol solution to measure the corresponding absorbance value (C _blank ). An equal amount of distilled water replaces the sample solution. Measure the corresponding absorbance value (C _control ) and calculate the hydroxyl radical scavenging rate. The formula is as follows:

Clearance rate (%) = [1-(C _sample -C _blank )/C _control ]×100;

The results are shown in Figure 2. The lowest IC ₅₀ of DPPH, ABTS and -OH free radical scavenging abilities of sea buckthorn pomace water-soluble dietary fiber and sea buckthorn pomace water-insoluble dietary fiber are 82.00 μg/mL, 438.97 μg/mL and 333.03 μg respectively. /mL.

According to embodiments of the present invention, by modifying sea buckthorn pomace dietary fiber, a method of preparing high-quality sea buckthorn pomace dietary fiber turns waste into treasure and realizes comprehensive utilization of by-products of sea buckthorn pomace. The invention has the advantages that the preparation process is simple, and no toxic or harmful substances are produced during the processing. It can not only retain the biological activity of the prepared sea buckthorn pomace dietary fiber to the maximum extent, but also has high safety.

In the description of this specification, reference to the terms "one embodiment," "some embodiments," "an example," "specific examples," or "some examples" or the like means that specific features are described in connection with the embodiment or example. , structures, materials or features are included in at least one embodiment or example of the invention. In this specification, schematic expressions of the above terms should not be understood as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may join and combine the different embodiments or examples described in this specification.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above-mentioned embodiments are illustrative and should not be construed as limitations of the present invention. Those of ordinary skill in the art can make modifications to the above-mentioned embodiments within the scope of the present invention. The embodiments are subject to changes, modifications, substitutions and variations.

Claims (4)

1. The method for preparing the dietary fiber by utilizing the solid state fermentation of the sea buckthorn pomace is characterized by comprising the following steps of:

(1) Pretreating sea-buckthorn pomace, adding distilled water according to the mass ratio of 1:20, uniformly mixing, and regulating the pH value to 4.0 to obtain sea-buckthorn pomace slurry;

(2) Adding 1.0% of cellulase, 1.0% of pectase, 0.2% of xylanase and 0.2% of beta-glucanase into the sea buckthorn fruit residue pulp, carrying out ultrasonic enzymolysis for 30 min-1 h at the enzymolysis temperature of 55 ℃ and ultrasonic power of 250W, inactivating enzyme at high temperature, and cooling to room temperature;

(3) Taking the sea buckthorn pomace slurry obtained after the enzymolysis in the step (2) as a substrate, inoculating zymophyte for fermentation treatment, wherein the fermentation temperature is 37 ℃, the pH is 4.5, and the fermentation time is 20 hours;

(4) Drying and grinding the sea buckthorn fruit residue pulp fermented in the step (3), adding distilled water into the sea buckthorn fruit residue pulp according to the mass ratio of the material to the liquid of 1:20, performing ultrasonic extraction for 30min at the ultrasonic power of 250W in the temperature environment of 70 ℃, and filtering the sea buckthorn fruit residue pulp under reduced pressure after extraction, and collecting filter residues and filtrate;

(5) Concentrating the filtrate in the step (4), adding 95% ethanol into the prepared concentrated solution according to the volume ratio of 1:10, standing for 8 hours after ultrasonic treatment for 2 hours, removing supernatant fluid with ultrasonic power of 250W to prepare concentrated precipitate, and performing vacuum freeze drying to prepare the water-soluble sea buckthorn fruit residue dietary fiber;

(6) Adding distilled water into the filter residue obtained in the step (4) according to the mass ratio of the feed liquid of 1:20, uniformly mixing, adjusting the pH value to 4.0, placing in a water bath at 110 ℃ for 1h, filtering, and vacuum freeze-drying the filter residue to obtain the water-insoluble sea buckthorn fruit residue dietary fiber.

2. The method of claim 1, wherein the fermentation broth is 1:1 streptococcus thermophilus and lactobacillus bulgaricus.

3. The method of claim 1, wherein the fermentation broth is inoculated in an amount of 3.5% by mass of the seabuckthorn pomace.

4. The method of claim 1, wherein the cellulase enzyme activity is 40000U/g, the pectinase enzyme activity is 80000U/g, the xylanase enzyme activity is 40000U/g, and the β -glucanase enzyme activity is 10000U/g.