NZ754367B2 - Dietary fiber and preparation method thereof - Google Patents

Abstract

The present invention provides a dietary fiber and a preparation method thereof, and the preparation method comprises the following steps: 1) mixing mulberry pomace with water, then pulping to obtain a pomace puree; 2) adding medium components to the pomace puree, then inoculating a compound strain for fermentation, and ending the fermentation when pH of a fermentation liquid is 4-5, to obtain a fermented puree; 3) subjecting the fermented puree to an alcohol precipitation treatment, filtering and drying a precipitate, to obtain the dietary fiber; where the compound strain comprises Lactobacillus plantarum, Monascus, and Bacillus subtilis. The preparation method performs a mixed fermentation to mulberry pomace by choosing a compound strain, thereby not only improving the total content of the dietary fiber in a product, but also improving the content of a soluble dietary fiber in the product. The present invention also relates to the Lactobacillus plantarum strain having a deposit number of GDMCC No. 60614. for fermentation, and ending the fermentation when pH of a fermentation liquid is 4-5, to obtain a fermented puree; 3) subjecting the fermented puree to an alcohol precipitation treatment, filtering and drying a precipitate, to obtain the dietary fiber; where the compound strain comprises Lactobacillus plantarum, Monascus, and Bacillus subtilis. The preparation method performs a mixed fermentation to mulberry pomace by choosing a compound strain, thereby not only improving the total content of the dietary fiber in a product, but also improving the content of a soluble dietary fiber in the product. The present invention also relates to the Lactobacillus plantarum strain having a deposit number of GDMCC No. 60614.

Description

DIETARY FIBER AND PREPARATION METHOD THEREOF TECHNICAL FIELD This application claims ty from Chinese patent application 201910229585.7, filed 25 March 2019, the entire content of which is incorporated by reference.

[0002] The present invention relates to a dietary fiber and, in particular, to a y fiber and a preparation method thereof, and belongs to the field of agricultural by-product deep processing.

BACKGROUND Dietary fiber refers to a carbohydrate polymer that cannot be digested and absorbed in the small intestine and has a degree of polymerization of not less than 10. It mainly includes pectin, lignin, ose and hemicellulose, and is known as the “seventh largest nutrient”. According to the difference in solubility, it may be d into two types: solubledietary fiber (SDF) and insoluble dietary fiber (IDF), both of which have different physiological structures and healthcare ons in a human body, and physiological functions of the solubledietary fiber is superior to that of the insoluble dietary fiber. At present, by-products such as scraps and wastes in food processing are the main raw materials for ing the dietary fiber. As there are a lot of impurities such as water, protein, fat, starch and ash in these raw materials, and the proportion of solubledietary fiber with physiological ons contained therein is low, it is a general concern in the industry to e purity and yield of dietary fiber in the current process technology by removing impurities and interference ents when preparing dietary fiber, and there are also a lot of reports about the research and the improvement of the relevant extraction process. On the other hand, quality and physiological functions of the dietary fiber in raw materials are improved by effective means, especially increasing the content of SDF while increasing the total yield of dietary fiber so as to improve physiological functions of the dietary fiber.

Mulberry is also known as sorosis. It has been confirmed from modern researches that mulberry fruits are rich in active protein, vitamin, amino acid, carotene, mineral, resveratrol, anthocyanin and other ingredients. Its nutrition is 5-6 times of apples and 4 times of grapes, and the dietary fiber thereof is above average compared to r foods. At the present stage, the extraction of dietary fiber in mulberry pomace is performed by acid extraction or alkali extraction, which may not only result in a low t of total of dietary fiber in a extract due to a low extraction rate, but also result in a certain negative effect on ry pomace raw materials and performances of dietary fiber due to acid and alkali conditions. It is an object of the present ion to go some way to overcome these problems and/or to at least e the public with a useful .

SUMMARY [0004a] In a first aspect the present invention provides a method for preparing a dietary fiber, comprising the following steps: 1) mixing mulberry pomace with water, then pulping to obtain a pomace puree; 2) adding medium components to the pomace puree, then inoculating a compound strain for fermentation, and ending the fermentation when pH of a fermentation liquid is 4-5, to obtain a fermented puree; 3) subjecting the fermented puree to an alcohol precipitation treatment, filtering and drying a precipitate, to obtain the dietary fiber; n the compound strain comprises Lactobacillus plantarum, Monascus, and Bacillus subtilis. [0004b] In a second aspect the present invention provides a y fiber obtained by the preparation method according to the first aspect, wherein the content of soluble dietary fiber is not less than 86%. [0004c] In a third aspect the present invention es acillus plantarum, wherein the acillus plantarum has a deposit number of GDMCC No. 60614.

Also described is a method for preparing a dietary fiber, a mixed fermentation is performed by choosing a compound strain, a product obtained thereby not only has an increased content of total dietary fiber, but also has an sed content of the e y fiber.

Also described is a dietary fiber with an increased content and an improved quality of the soluble y fiber.

The invention provides a method for preparing a dietary fiber, including the following steps:

[0008] 1) mixing mulberry pomace with water, then pulping to obtain a pomace puree; 2) adding medium components to the pomace puree, then inoculating a compound strain for fermentation, and ending the fermentation when pH of a fermentation liquid is 4-5, to obtain a fermented puree; 3) ting the fermented puree to an alcohol precipitation treatment, filtering and drying a precipitate, to obtain the dietary fiber; wherein the compound strain comprisesLactobacillus rum, Monascus, and us subtilis.

The mulberry pomace treated by the present invention is a by-product from ry fruit processing, mainly is pomace produced from brewing or juicing production with mulberry fruit raw materials, and a high-quality dietary fiber product may be obtained through the above mixed fermentation.

According to technical solutions of the present invention, before sending the mulberry pomace to the fermentation process, in addition to necessary atments, such as impurity removal, pulverization, and the like, the mulberry pomace is further pulped into a pomace puree with water to facilitate the fermentation process. For example, the mulberry pomace is first subjected to impurity removal and then broken into a particle size of 20 to 35 μm, which makes powder particles micronized, and porosity and specific surface area increased, and thereby significantly improving physicochemical properties of the dietary fiber. Further, water in an amount of 2 to 5 times of the pomace is added for pulping, in a specific embodiment, a mass ratio of added water to mulberry pomace raw materials is about 3:1 during the pulping.

In a system for mixed fermentation of a pulped pomace puree, it needs to contain necessary nutrients, which may be satisfied by adding medium ents including carbon source, en source, inorganic salt, trace element, etc. The persons of ry skill in the art may select le media components ing to natures and compositions of a fermentation ate, as well as the needs of strains or a complex strain used. Specifically, the carbon source may be selected from sucrose, white granulated sugar, glucose, maltose, etc. The nitrogen source may be derived from peptone, beef extract, ammonium chloride, milk powder, ammonium nitrate, potassium nitrate, etc. The inorganic salt may be at least one of magnesium sulfate, manganese sulfate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, etc. In a particular embodiment described herein, the medium components include skimmed milk powder and white granulated sugar, where the mass of the skimmed milk powder is 15-20% of the mass of the pomace puree, and the mass of the white granulated sugar is 10-15% of the mass of the pomace puree. In a specific operation, the skimmed milk powder and the white granulated sugar are added to the pomace puree, and after being evenly stirred, inoculation of strain and fermentation may be carried out.

In preparation s described herein, the compound strain is a compound of Lactobacillus plantarum, Monascus, and Bacillus subtilis. The ation of the three strains provides high-quality y fiber products needed.

[0016] TheLactobacillus plantarum produces a lot of organic acids during fermentation, the organic acids make glycosidic bonds of celluloses in mulberry fruit break by providing protons, thereby producing new reducing ends, so that macromolecule polymerization degree of dietary fibers in the mulberry pomace is decreasing, some fiber materials are degraded and converted, and some will be converted into non-digestible soluble polysaccharides, thereby increasing the content of the solubledietary fiber. However, the inventor of the t application found from ches that using a compound strain agent formed by introduction of theMonascus and Bacillus subtilis and r in combination with the Lactobacillus plantarum for fermentation of the above mulberry pomace puree may greatly improve the content and physiological functions of the dietary fiber. From the mechanism, it shall be that the compound strain agent promotes the fermentation of substrate and at the same time promotes the ion of various cellulase, amylase, protease, and the like, y achieving an increased content and promoted swelling performance of the dietary fiber.

Same as conventional fermentation processes, a process described herein for preparing the dietary fiber using the above-mentioned strains also includes the operations of strain activation, seed solution preparation, inoculation of the seed solution into a tation medium for enting the fermentation, where the Lactobacillus plantarum, Monascus, and Bacillus subtilis used are cial products, and ications of the strains can be selected according to the performance and vigor that required by the fermentation.

[0018] Activation of the above three kinds of strains and preparation the seed solutions thereof can be performed according to conventional methods.

In one embodiment, seed solutions ofLactobacillus plantarum, us, and Bacillus subtilis may be mixed in a volume ratio of (1-2): (1-1.5): (1-1.5). A mixed seed solution is inoculated into a puree containing medium components to achieve a larger improvement of dietary fiber content and logical functions.

Further, when the volume ratio of the seed solutions ofLactobacillus plantarum, Monascus, and Bacillus subtilis is 1:1:1, the three strains work istically to the greatest extent, so that content and physiological functions of the dietary fiber are significantly improved.

[0021] In addition, the quality of the dietary fiber may be optimized by controlling an inoculum amount. When the inoculum amount is 5-10% (v/v), that is, the volume of a mixed seed solution is 5-10% of the volume of a fermentation substrate containing medium components, which may shorten the breeding time and reduce ility of ial growth at a low cost, and quickly obtain a high-quality fermented puree.

[0022] The present invention does not ly limit the fermentation conditions, as long as they are le for the above compound strain to product the dietary fiber, the fermentation s will produce acids, and when the fermentation liquid is become weak acidic, it is considered that the fermentation is completed, that is, when pH of the fermentation liquid detected is 4-5, terminate the fermentation. Controlling pH in above range is to ensure quality of the dietary fiber (total dietary fiber content and solubledietary fiber content), and to facilitate compatibility of the dietary fiber with other ingredients, so that a product has a wider applicability.

In a specific embodiment of the present invention, a ature for fermentation in step 2) may be controlled as 30-40 °C, and a time for fermentation may be controlled as 30-36 h. Using the compound strain to ferment the pomace puree under these condition is conducive to obtain a better y product.

Further, before the inoculation and fermentation, the prepared pomace puree may be ized as needed. Sterilization may be ed by means of water bath heating in the technical solutions of the ion. For example, heat sterilization is proceeded in a water bath at 90 ° C for 15 min.

After the fermentation is completed, the fermented puree needs to be further treated, which includes an alcohol itation treatment and a subsequent drying ent.

Specifically, the fermented puree is filtered, and filter residues are rinsed with water, for example, rinsing with running water for 1-3 times, and a filtrate is collected, and the filtrate includes solubledietary fiber and insoluble dietary fiber. By adding ethanol to the filtrate, the edietary fiber therein may be precipitated, and a precipitate is collected by solid-liquid separation (for e a fugation operation), rinsed repeatedly with absolute ethanol until l, then dried, and the dietary fiber of the present invention is obtained. During the alcohol precipitation, ethanol is added to the filtrate at a volume ratio of ethanol to filtrate (3-4):1, and standing for precipitation. Generally, a standing time may be controlled as 2-5 hours, thereby ensuring the m precipitation of the edietary fiber.

A drying method described herein may be freeze drying or spray drying.

Where, a precipitation, which is rinsed with absolute ethanol until neutral, may be directly subjected to the freeze drying. In a specific operation, the precipitate may be pre-freezed in a -80 °C ultra-low temperature refrigerator for 12 h, then transferred to a lyophilizer, and continuously dried for 48 hours under the following conditions: a vacuum degree of 0.12 mbar, a cold trap temperature of -50 °C, and a baffle plate heating temperature of 20 °C, thus a soluble dietary fiber of the present invention is obtained.

When the spray drying is selected for drying treatment, in order to optimize morphology of the dietary fiber, a precipitation, which is rinsed with absolute ethanol until neutral, may be subjected to homogenization, then spray drying. Specifically, a neutral precipitate is added with 80-90 °C of water, and a homogenization treatment is performed after the mixture is evenly stirred. The amount of water added may be controlled such that the mass ratio of the water to the precipitate is (1-2):1. According to needs, there may be two-stage nization, that is, a first-stage homogenization with a temperature of 60-70 °C, a pressure of 15-25 Mpa, and then the pressure is increased for a second-stage homogenization, and the second-stage homogenization has a temperature of 60-70 °C, a pressure of 30-40Mpa. Specifically, after the first-stage homogenization is carried out for 2-3 times, then performing the second-stage homogenization for 2-3 times. Subsequently, without affecting logical functions of the dietary fiber, a working pump speed of a spray tower is set as 300-325r/h, an inlet air temperature is set as 200-250°C, and an outlet air temperature is set as 80-100°C, so as to dry a nized liquid, and a drying nt may be added during a drying process to ze the drying effect. Based on the quality of the homogenized liquid, the drying adjuvant includes 15-20% of maltodextrin, 5%-10% ofgum arabic, 0.5-1% of β-cyclodextrin.

As mentioned above, the Lactobacillus plantarum plays an important role in degradation and transformation of oses in the mulberry pomace, and h synergy with the Monascus and Bacillus subtilis, the content and quality of the dietary fiber prepared are improved, which include significantly improving water holding capacity, swelling power, oil g capacity and adsorption of NO2- and Cd2+ of the dietary fiber.

In a specific embodiment described herein, a strain obacillus plantarum isolated and purified from ry pomace is used: the mulberry pomace, after being ultramicroporwderized to a le size of 20-35 μm, is added with water at 35 °C (a mass ratio of mulberry fruit to water is 1:3) and soaked for 16 hours, filtered, and the ry pomace was mixed with water and pulped for 2-3 times (a mass ratio of the water to the mulberry pomace is 1.5:1 in each pulping), filtered, and a filtrate is subjected to a constant temperature fermentation at 35 °C, after about 5 hours, the filtrate is obviously divided into upper, middle and lower layers.

The middle layer of the filtrate is sampled, and streaking culture is performed in a MRS solid medium at a culture temperature of 25 °C. After bacterial colonies are grown, an ndent colony is selected, where a sample is picked with an inoculation , placed on a glass slide, stained with a toluidine blue dye solution, and observed under a microscope whether there is a colony with a morphology of Lactobacillus plantarum. If there is, reproduction is expanded and re-identified, which was repeated for about 4 times, to obtain a cell purebreed similar to Lactobacillus plantarum. ce determination, analysis, and phylogenetic tree g of 16 S rDNA and pheS are carried out on the above-mentioned similar Lactobacillus plantarum, sequencing s go through BLAST for homologous sequence search using GenBank database, then go through MEGA5.0 software for homology analysis, similarity calculations are repeated for 1000 times, a phylogenetic tree based on confidence is structured, and y the strain is identified asLactobacillus plantarum. The acillus plantarum obtained by the above method has a deposit number of GDMCC No. 60614. Phenotypic characteristics of the acillus plantarum (GDMCC No. 60614) described herein are: a strain with round ends and straight bars, Gram-positive, non-spore, facultative anaerobic, surface colony diameter of about 3mm, convex, round, smooth surface, fine, white, occasionally light yellow or dark yellow.

Using the acillus plantarum (GDMCC No. 60614) provided by the present ion, compared with similar strains, such as a commercially availableLactobacillus plantarum (model: YS-JZ0468), not only increases y fiber content, promotes physiological functions in a fermentation product, but also s inoculation amount needed, shows a significant advantage in production efficiency and cost.

The present invention also provides a dietary fiber obtained by the above preparation method, wherein the content of soluble dietary fiber is not less than 86%.

Compared with a dietary fiber obtained from mulberry pomace by an acid extraction method, the dietary fiber of the present invention increases the water holding capacity, the expansion force and the oil holding power by 35.65%, 72.35%, , respectively, and increases the adsorption capacity on NO2- by 6.3%, the adsorption capacity on Cd2+ by 7.53%, which contributes to discharge of excess water, oil and harmful substances from human body. In addition, the dietary fiber also has a significant effect on the ion of high blood glucose and hyperlipidemia.

TheLactobacillus plantarum used in ments of the present invention has been deposited in the Guangdong Microbial Culture Center (abbreviated as GDMCC) on March 19, 2019, and its address is Provincial Microbiologic Institute at 5th floor, ng 59, No. 100, Xianlie Middle Road, Guangzhou, a deposit number is GDMCC No. 60614.

[0038] The present invention provides a method for preparing a dietary fiber using a compound strain through a mixed fermentation process, which may not only utilize pomace obtained after the processing of mulberry fruit, increase added values of mulberry fruit products, but also, compared with the current conventional used y fiber preparation technologies, may significantly increase the total content of the dietary fiber and the content of solubledietary fiber, improve physiological functions of the dietary fiber, and enhance edibleness and medical value of the dietary fiber.

DESCRIPTION OF EMBODIMENTS To make the objectives, technical solutions, and ages of embodiments of the present ion clearer, the ing clearly and comprehensively describes the technical solutions in embodiments of the present invention with reference to the accompanying drawings in embodiments of the present invention. Apparently, the bed embodiments are merely a part rather than all embodiments of the present ion. All other embodiments obtained by persons of ordinary skill in the art based on embodiments of the present invention without creative effort shall fall within the tion scope of the t invention.

[0040] Example 1 Lactobacillus plantarum used in this example was the Lactobacillus plantarum with GDMCC No. 60614, andMonascus (model: CS-J0150) and Bacillus subtilis (model: 70-0) were commercially available.

Where,

[0043] The Lactobacillus plantarum (GDMCC No. 60614) was activated and a seed solution thereof was prepared as follows: A frozen-preserved strain was thawed, ed at 37 °C after being coated, a single colony was picked and placed into a MRS broth medium, the activation was performed twice at 37 °C, and then added with a MRS broth and 10 wt% of mulberry pomace aqueous on (a volume ratio of the broth and the 10wt% of mulberry pomace aqueous solution is 1:1; the 10wt% of mulberry pomace aqueous solution is a mixture of mulberry pomace and water, the content of mulberry pomace therein is 10%), the activation was performed twice at 37 °C; finally added with the MRS broth and the 10wt% of mulberry pomace aqueous solution (a volume ratio of the MRS broth and the 10wt% of ry pomace aqueous on is 1:9), and shaking cultured at 150r/min at about 37°C for 16-20h, to obtain a seed solution of the Lactobacillus plantarum (GDMCC No.60614) with a spore number of 108 / m

[0045] The Monascus was activated and a seed solution thereof was prepared as follows: theMonascus strain was inoculated on a slant malt AGAR medium (newly prepared), and stood for activation in a constant temperature incubator at 30-35 °C for 7-14 days. uently, an appropriate amount of sterile water was added to the fresh strain slope, and spores in the slope were scraped off with a spore shovel, a strain suspension was prepared, which was inoculated to a seed culture flask with glass beads, and cultured in a shaker at 150 r/min at 30° C for 4-5 days, and a viable count was 107 CFU/mL.

Where, the composition of a seed medium: 6% of glycerol, 2.5% of beef extract, 1% of peptone, 1% of sodium nitrate, 2.5% of glucose, 0.1% of magnesium sulfate.

TheBacillus subtilis was activated and a seed solution thereof was prepared as follows: a Bacillus subtilis was inoculated into a fermentation medium, transferred from -70 °C to -20 °C, activated at 4 °C, and placed in a incubator at 37 °C and ed for 24 hours after plate streaking. Subsequently, 1-2 rings of Bacillus subtilis were taken from the plate and ated into a 30 mL seed , and shaking cultured at 180 r/min at 37 °C for 12 h, and the viable count was 107 CFU/mL.

[0048] Where, a fermentation medium was formulated using 15.0 g/L of starch, 20.0 g/L of soybean meal, 1.0 g/L of ium dihydrogen phosphate, 0.5 g/L of um hydrogen phosphate, 0.5 g/L of calcium carbonate, 0.5 g/L of magnesium sulfate, 0.2 g/L of manganese sulfate.

A seed medium was formulated using 10.0 g/L of starch, 5.0 g/L of yeast t, 0.5 g/L of disodium hydrogen phosphate, 0.5 g/L of magnesium sulfate, and pH of 7.0. Before the medium was used, it needed to be sterilized at 121 °C , 0.1 Mpa for 20 min.

A preparation method of a dietary fiber of this embodiment includes the following steps: 1) mixing mulberry pomace with water, lling a mass ratio of ries to the water as 1:3, crushing and pulping using a crusher to obtain a pomace puree; the mulberry pomace of the present embodiment was a by-product after juice production, which had a le size of 20 ~ 35μm; 2) adding skimmed milk powder and white ated sugar to the pomace puree, where a mass of the skimmed milk powder is 18% of the mass of the pomace puree, and a mass of the white granulated sugar is 12% of the mass of the pomace puree. After being evenly stirred, the pomace puree containing the skimmed milk powder and white granulated sugar was heated and sterilized in a water bath with a water bath temperature of 90 °C and a sterilization time of 15 min; 3) mixing activated seed solutions ofLactobacillus plantarum, Monascus and Bacillus subtilis (1:1:1) to obtain a seed solution of the compound strain, and inoculating the seed solution of the compound strain in the pomace puree in the step 2) for fermentation, where an inoculation amount was 10% (v/v); a tation temperature was about 35 °C, and when pH of fermentation liquid was 4-5, terminate the fermentation, and the fermentation cycle is 25 h;

[0055] 4) filtering the fermented puree, rinsing filter residues with running water for 3 times, merging of tes, standing for precipitation using anhydrous ethanol with a volume of 3 times of the filtrate for 4 hours, then centrifuging to obtain a precipitate, and repeatedly rinsing the precipitate with ous ethanol until neutral; In the process, a mass fraction of a total dietary fiber in the te was detected according to the determination of dietary fiber in food GB 5009.88-2014, the result was shown in Table 1; 5) adding 80-90 °C of water to the above itate with a mass ratio of the water to the precipitate of 1:1, after evenly stirring, performing a first-stage homogenization, twice, at 60 °C and 20 Mpa, then raising temperature and pressure to perform a second-stage homogenization, three times, at 65 °C and 35 Mpa; 6) spray-dring a homogenized product, controlling a rotation speed of a drying pump to be 300 r/h, with an inlet air temperature of 250 °C and an outlet air temperature of 100 °C, to obtain a dietary fiber 1# of the present example.

According to the determination of dietary fiber in food GB 5009.88-2014, components and biological functions of the dietary fiber 1# were ed, the s were shown in Table 2 and Table 3.

Example 2 Lactobacillus plantarum in this example was a commercially available strain (model: YS-JZ0468), except that theLactobacillus plantarum and its activation manner are different from the Example 1, the other conditions are all same to that of e 1, and a dietary fiber 2# of this example was obtained.

The mass content of a total dietary fiber in a filtrate before alcohol precipitation in the present example was detected according to the detection method in Example 1, and the result was shown in Table 1;

[0063] According to the detection method in Example 1, components and biological functions of the dietary fiber 2# were detected, the results were shown in Table 2 and Table 3.

The Lactobacillus plantarum was activated and a seed solution thereof was prepared as follows: A MRS broth medium was prepared and sterilized at 120 °C for 20 min. A strain held on a slope at 4 °C was picked up and inoculated into 25 mL of the sterilized MRS broth medium and cultured in an incubator at 37 °C for 12 h to activate the . A activated strain suspension was taken and inoculated into a test tube containing 10 mL of the MRS broth medium with 1% inoculum amount (v/v), values of OD580nm were measured every 2 h from the start of inoculation (taking three test tubes every time for parallel experiments), and 1 mL of the strain suspension was taken up for each test tube, gradiently diluted, then inoculated into a MRS AGAR plate e dish, cultured in the incubator at 37 °C for 12 h, with a viable count of 108 .

Example 3 In the ation method of the present embodiment, the volume ratio of activated seed ons ofLactobacillus plantarum, us and us subtilis is 2:1.5:1.5, and the rest ions are all same to that of Example 1, a dietary fiber 3# of the present example was obtained.

The mass content of a total dietary fiber in a filtrate before l precipitation in the present Example was detected according to the detection method in Example 1, and the result was shown in Table 1; ing to the ion method in Example 1, components and biological ons of the dietary fiber 3# were detected, the results were shown in Table 2 and Table 3.

Control example A ation method of a dietary fiber in the control example includes the ing steps: Mulberry pomace was crushed and passed through a 40 mesh sieve for use. 20 g of the mulberry pomace was accurately weighed, a pH value was adjusted with hydrochloric acid to 1 and a ratio of material to liquid was 1:20, extracted with hot water for 8h, then subjected to suction filtration, filter residue was insoluble dietary fiber; a filtrate was collected, added with 4 times volume of ethanol, kept warm at 60 °C for 1 h, subjected to suction filtration again, a precipitate was a solubledietary fiber, and a sample was obtained through drying.

The mass content of a total dietary fiber in a filtrate before alcohol precipitation in the present example was detected according to the detection method in e 1, and the result was shown in Table 1; According to the detection method in Example 1, ents and biological functions of the prepared dietary fiber in the control example were detected, the results were shown in Table 2 and Table 3.

Table 1 Total dietary fiber mass content in the filtrates of Examples 1-3 and Control example Control Example 1 e 2 Example 3 example Total dietary fiber wt% 85.69 80.13 83.12 70.56 It could be seen from Table 1 that the preparation methods of the present invention significantly increases total dietary fiber content in fermentation products.

Table 2 ents list of dietary fiber1-3# and control dietary fiber soluble dietary soluble y fiber accounts water wt% protein wt% ash wt% fiber % for pomace wt% 1# 4.70 5.02 2.11 88.17 14.36 2# 4.71 5.49 2.86 86.94 12.62 3# 4.73 5.08 2.32 87.87 13.35 Control 4.71 6.98 7.56 80.75 3.25 It could be seen from Table 2 that compared with the method of control example, the preparation methods of the present invention obtains more soluble dietary fiber from mulberry pomace, and significantly increases the content of the soluble y fiber in the fermentation products.

Table 3 Physiological function data list of dietary fiber 1-3# and control dietary fiber water holding expansion force/ oil holding NO-2 adsorption Cd2+ adsorption capacity/（g/g） （ml/g） capacity/（g/g） amount/（μg/g） amount /（mg/g） 1# 4.23 3.89 2.58 340.26 9.56 2# 4.12 2.50 1.96 326.52 9.16 3# 4.19 3.05 2.13 337.58 9.08 Control 3.11 1.85 1.73 309.56 8.89

[0077] It could be seen from Table 3 that the dietary fiber obtained by the preparation methods of the present invention has greatly improved physiological functions compared with the dietary fiber of the control example.

Test Example 1 Evaluation of hypoglycemic function 1. mental animals

[0080] Healthy BALB/c mice, weight of 16-20 g, average of 18 g, 4-6 weeks old, were sed from the Experimental Animal Center of i Medical University. The healthy mice free accessed to food, had sufficient fresh ng water, and were kept in a room with lled light and temperature, where temperature is controlled at 21 ± 2 °C and light is provided from 8:00 to 20: 00. All animal experiments were d out in accordance with Laboratory animal welfare and trial guidelines issued by NIH. 2. Treatment process Ten mice were randomly selected as a normal control group, and the mice in the normal control group were fed with basal feed of normal growth period; the remaining mice were fed with high-sugar feed, the composition of which was 1.5% of cholesterol, 10% of lard, 5% of sucrose, 0.25% of sodium cholate, 83.25% of basal feed. After 30 days, 80 mice were selected from the mice fed with high-sugar feed, and were randomly divided into 8 groups: model group, control group, se group A, medium-dose group A, high-dose group A, low-dose group B, medium dose group B, high dose group B.

Administrating a test substance to the control group, the low-dose group A, the middle-dose group A, the high-dose group A, the low-dose group B, the middle-dose group B, and the high-dose group B, and the test substance was administered by oral gavage, each of mice was subjected to intragastric gavage at 0.15 mL/10 g once every morning, during which the mice were free access to water and food, the test substances for mice in each group were shown in Table 4. ation was performed at the edge of cages every day and it shall pay attention to the timely replacement of animal padding. During this period, mice in the normal control group were continued to be fed with the basal feed, and mice in the model group were continued to be fed with high-sugar feed.

[0084] Whole bloods of mice in the nine groups were collected in 1.5 mL of centrifuge tubes by an eyeball method on the day of 0th, 7th, 14th after the administration, respectively, after standing for incubation in an incubator at 37 °C for 30 min, centrifuging at 3500 r/min at a low-temperature for 10 min, and supernatants were sera. The sera were ed into clean centrifuge tubes for the detection of blood glucose content. The test s were shown in Table 5.

Data of mice in each group in Table 5 were expressed as mean ± standard deviation. Results were statistically analyzed using a Statistical is software SPSS21.0, and statistically processed using ANOVA test and Duncan test.

Table 4 Test nce design for mice in each group in Test Example 1  group administration category dosage Dietary fiber the of control l group 20mg/kg/bw low-dose group A dietary fiber1# 2mg/kg/bw middle-dose group A dietary fiber1# 20mg/kg/bw high-dose group A dietary fiber1# 200 mg/kg/bw low-dose group B dietary fiber2# 2mg/kg/bw middle-dose group B dietary fiber2# g/bw high-dose group B dietary fiber2# 200 mg/kg/bw Table 5 Results of blood glucose test of mice in each group group 0th day 7th day 14th day normal l group 5.42±0.61 5.46±0.70 5.34±0.62 model group 11.60±3.17 3.60 14.10±3.19 control group 11.36±1.35 9.31±1.23 9.12±2.12 low-dose group A 11.12±1.98 9.13±1.51 8.90±1.74 middle-dose group A 11.24±2.31 8.52±1.24 8.42±3.96* high-dose group A 11.14±1.58 .33* 5.89±1.74** low-dose group B 11.24±1.62 9.88±1.23 1.33 middle-dose group B 11.34±2.01 .12 10.37±2.77 high-dose group B 11.23±1.45 8.98±0.95 9.07±1.23* * indicated that there was a significant difference between the treated group and the model group (p<0.05), and ** indicated there was an extremely significant difference between the treated group and the model group (p<0.01).

It could be seen from Table 5: 1. Compared with the dietary fiber in the control example, the dietary fiber obtained by the preparation method of the present invention effectively reduces blood glucose content;

[0089] 2. On the 14th day after of administration, compared with the model group, in the low-dose group A, the middle-dose group A, and the ose group A, blood glucose decreased by 36.9%, 40.28%, and 58.22%, respectively; in the low-dose group B, the -dose group B, and the high-dose group B, blood glucose sed by 8.79%, , and , respectively, which thus ted that the dietary fiber obtained by the preparation method of the present invention had a icant regulation and improvement effect on glucose metabolism in diabetic mice, and was dose-dependent.

Test Example 2 Evaluation of hypolipidemic on 1. Experimental rats Healthy adult male Wistar rats, weight of 150-200 g, average of 173.5 g, 7-8 weeks old, were purchased from the Experimental Animal Center of Guangxi Medical University. The y rats free accessed to food, had sufficient fresh drinking water, and were kept in a room with controlled light and temperature, where temperature is controlled at 16-20 °C and light is ed from 8:00 to 20: 00. All animal experiments were carried out in ance with Laboratory animal welfare and trial guidelines issued by NIH. 2. Treatment process

[0094] Eight rats were randomly selected as a normal control group, and the rats in the normal control group were fed with basal feed of normal growth period; the remaining rats were fed with high-fat feed, the composition of which was basal feed 60%, lard 12%, milk powder 6%, egg 5%, fried peanut 5%, sugar 10%, salt 1%, sesame oil 1%. After 14 days, 64 rats were selected from the rats fed with high-fat feed, and were randomly divided into 8 groups: model group, control group, low-dose group A, medium-dose group A, high-dose group A, low-dose group B, medium dose group B, high dose group B.

Rats in each group, after being fasted for about 12 hours, were anesthetized with 1% of sodium barbiturate solution, and about 3 mL of blood was taken from the abdominal aorta for detection of total cholesterol (TC), triglyceride (TG), and low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C), and the results were shown in Table 6 below.

Subsequently, administrating a test substance to the control group, the low-dose group A, the middle-dose group A, the high-dose group A, the low-dose group B, the middle-dose group B, and the high-dose group B, and the rats were subjected to intragastric gavage with a dose of 0.15 mL/10 g once a day, and were continuously administrated for 28 days, during which the rats were free access to water and food. The test substances for rats in each group were shown in Table 7. Observation was performed at the edge of cages every day and it shall pay attention to the timely replacement of animal padding. And animal body weight was weighed once a week before and after the administration, as shown in Table 8 (Table 8, the weight in the normal control group and the model group after administration refers to the weight of rates in the normal control group fed with basal feed and the weight of rates in the model group fed with at feed after 28 days). During this , rats in the normal control group were continued to be fed with the basal feed, and the rats in the model group were continued to be fed with high-fat feed.

After 28 days, rats in each group, after being fasted for about 12 hours, were anesthetized with 1% of sodium barbiturate solution, and about 3 mL of blood was taken from the abdominal aorta for detection of total cholesterol (TC), triglyceride (TG), and low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C), and the results were shown in Table 9 below.

Data of rats in each group in Tables 6, 8 and 9 were expressed as mean ± rd deviation. Results were statistically analyzed using a Statistical analysis software SPSS21.0, and statistically processed using ANOVA test and Duncan test.

Table 6 Blood lipid test results of rats in each group before administration TC(mmol/L) TG(mmol/L) mmol/L) LDL-C(mmol/L) normal control group .21 1.60±0.16 1.44±0.08 0.17±0.05 model group 4.32±0.22 2.68±0.36 1.64±0.06 0.31±0.03 control group 4.21±0.12 2.34±0.16 1.65±0.03 .01 low-dose group A 4.33±0.41 2.51±0.33 1.59±0.12 0.27±0.02 middle-dose group A 4.11±0.32 2.76±0.67 .1 0.32±0.07 high-dose group A 4.15±0.34 2.81±0.89 1.62±0.09 0.33±0.04 low-dose group B 4.21±0.43 2.59±0.43 1.68±0.09 0.29±0.02 middle-dose group B .36 2.54±0.62 .08 0.28±0.05 high-dose group B 4.19±0.23 2.53±0.55 1.66±0.05 0.31±0.04 Table 7 Test substance design for mice in each group in Test Example 2 administration category dosage Dietary fiber of the control control group 20mg/kg/bw example low-dose group A dietary fiber 1# 2mg/kg/bw middle-dose group A dietary fiber 1# 20mg/kg/bw ose group A y fiber 1# 200 mg/kg/bw se group B y fiber2# 2mg/kg/bw middle-dose group B dietary fiber 2# 20mg/kg/bw high-dose group B dietary fiber 2# 200 mg/kg/bw Table 8 Weight determination results of rats in each group before and after stration before after administration administration normal control group 181.42±8.9 186.75±5.4 model group 255.43±11.2 270.43±8.7 control group 254.11±10.5 243.5±9.5 low-dose group A 255.85±5.6 223.25±7.3 middle-dose group A 256.45±9.5 201.11±10.4* high-dose group A 254.69±6.9 189.56±11.5** low-dose group B 255.78±10.2 ±10.2 middle-dose group B 255.13±6.3 211.45±8.9 high-dose group B 253.12±5.8 193.56±7.5* * indicated that there was a significant ence n the treated group and the model group (p<0.05), and ** indicated there was an extremely significant difference between the treated group and the model group (p<0.01).

It could be seen from Table 8 that compared with the model group, the rats in the low-dose group A, the medium-dose group A, and the high-dose group A had a weight decrease of 17.45%, 25.63%, and 29.90%, respectively, the rats in the low-dose group B, the medium-dose group B, and the high-dose group B had a weight decrease of 9.24%, 21.81%, and 28.42%, respectively, which thus indicated that the dietary fiber obtained by the preparation method of the present invention had a significant regulation and improvement effect on obesity, and was dose-dependent.

Table 9 Blood lipid test results of rats in each group after administration TC(mmol/L) TG(mmol/L) HDL-C(mmol/L) LDL-C(mmol/L) normal control group 2.60±0.21 1.60±0.16 1.44±0.08 0.17±0.05 model group 4.32±0.22 2.68±0.36 1.64±0.06 0.31±0.03 control group 4.11±0.18 2.55±0.12 1.59±0.06 0.28±0.05 low-dose group A 3.85±0.12 2.29±0.17 1.57±0.09 0.26±0.03 middle-dose group A 3.71±0.22 2.15±0.24* 1.56±0.11 0.24±0.02 high-dose group A 3.43±0.15* 2.09±0.25** .05* 0.19±0.01* se group B 3.93±0.14 2.52±0.18 1.59±0.07 0.28±0.01 middle-dose group B .11 2.23±0.24 1.58±0.09 0.26±0.02 high-dose group B 3.56±0.14* 2.19±0.31* 1.53±0.06 0.23±0.04 * ted that there was a significant difference between the treatment group and the model group (p<0.05), and ** indicated there was an extremely significant ence between the treatment group and the model group (p<0.01).

It could be seen from Table 9:

[00103] 1. Compared with the dietary fiber in the control example, the dietary fiber obtained by the preparation method of the invention had a on of significantly reducing triglyceride in hyperlipidemia rats; ] 2. Compared with the model group, rats in the low-dose group A, the -dose group A, and the high-dose group A had a total triglyceride decrease of 8.76%, 22.1%, and 25.62%, respectively; rats in the low-dose group B, the medium-dose group B, and the high-dose group B had a total triglyceride decrease of 2.7%, 12.2%, and 13.44%, respectively, which thus indicated that the y fiber ed by the preparation method of the present invention had a significant tion and improvement effect on blood lipid metabolism, and was dose-dependent.

[00105] It should be noted that the foregoing embodiments are merely intended for bing the technical ons of the present invention other than limiting the present invention. Although the present invention is described in detail with reference to the foregoing embodiments, persons of ry skill in the art should understand that they may still make modifications to the technical ons described in the foregoing embodiments or make lent substitutions to some or all technical features thereof, and these modifications or substitutions do not make the nature of the corresponding technical solution departs from the scope of the technical solution of each embodiment of the present ion.

The term “comprising” as used in this specification and claims means “consisting at least in part of”. When reting statements in this specification, and claims which include the term “comprising”, it is to be understood that other features that are additional to the features prefaced by this term in each statement or claim may also be present. Related terms such as “comprise” and “comprised” are to be interpreted in similar manner.

In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of ing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

] In the description in this specification reference may be made to subject matter that is not within the scope of the claims of the current application. That subject matter should be y identifiable by a person skilled in the art and may assist in putting into practice the invention as defined in the claims of this application.

Claims (13)

1. A method for preparing a dietary fiber, sing the ing steps: 1) mixing ry pomace with water, then pulping to obtain a pomace puree; 2) adding medium components to the pomace puree, then inoculating a compound strain 5 for fermentation, and ending the fermentation when pH of a fermentation liquid is 4-5, to obtain a fermented puree; 3) subjecting the fermented puree to an alcohol precipitation treatment, filtering and drying a precipitate, to obtain the dietary fiber; wherein the compound strain comprises Lactobacillus plantarum, Monascus, and 10 Bacillus subtilis.

2. The method for preparing the dietary fiber ing to claim 1, wherein a volume ratio of seed solutions of theLactobacillus plantarum, Monascus, and Bacillus subtilis is (1-2): (1-1.5): (1-1.5) during inoculation.

3. The method for preparing the dietary fiber according to claim 2, wherein the volume 15 ratio of the seed solutions of the Lactobacillus plantarum, Monascus, and Bacillus is is 1:1:1 during inoculation.

4. The method for producing the dietary fiber according to claim 2 or 3, wherein in the fermentation, an inoculation amount of a seed solution of the compound strain is 5-10%.

5. The method for preparing the dietary fiber according to any one of claims 2 to 4, 20 wherein a temperature for the fermentation is 30-40 °C and a time for the fermentation is 30-36 h.

6. The method for producing the dietary fiber ing to any one of claims 1 to 5, wherein the Lactobacillus plantarum is isolated from mulberry fruit.

7. The method of preparing the dietary fiber according to claim 6, wherein the 25 acillus plantarum has a deposit number of GDMCC No. 60614.

8. The method of ing the dietary fiber ing to claim 1, wherein the alcohol precipitation treatment comprises: filtering the fermented puree, adding ethanol to a filtrate, and standing for 2-5 h; wherein a volume ratio of the ethanol to the filtrate is (3-4):1.

9. A dietary fiber ed by the preparation method according to any one of claims 1-8, wherein the content of soluble dietary fiber is not less than 86%. 5

10. Lactobacillus plantarum, n the acillus plantarum has a deposit number of GDMCC No. 60614.

11. A method as claimed in any one of claims 1 to 8 substantially as herein described and with reference to any example thereof.

12. A dietary fiber as d in claim 9 substantially as herein described and with 10 reference to any example thereof.

13. Lactobacillus plantarum as claimed in claim 10 substantially as herein described and with reference to any example thereof.