Fermented citrus pomace insoluble dietary fiber functional emulsion, preparation method and application thereof

Abstract

The application discloses a kind of fermented citrus dreg insoluble dietary fiber functional emulsion and preparation method and application.The application utilizes composite probiotic fermentation to be combined with composite enzyme processing, obtains modified citrus dreg insoluble dietary fiber, then with protein forms insoluble dietary fiber-protein covalent complex, is treated by ultrasonic and high speed shearing to obtain nutritional emulsion.Compared with prior art emulsion preparation method, the application utilizes fermentation to improve insoluble dietary fiber monosaccharide content, so that it is easy to occur Maillard reaction with protein to form stable covalent complex, and the nutritional ingredient delivery system droplet prepared by using the same as emulsifier is small, and environmental tolerance is strong, solve the problems such as poor emulsion stability, easy to aggregate, low encapsulation efficiency, improve the bioavailability of nutritional ingredients, and enhance the antioxidant activity of emulsion.The fermented citrus dreg insoluble dietary fiber functional emulsion obtained by the foregoing preparation method is a good biological delivery carrier, and can be applied in food, cosmetics and pharmaceuticals and other fields.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of food science and technology, and particularly relates to a fermented citrus peel residue insoluble dietary fiber functional emulsion as well as a preparation method and application thereof. BACKGROUND

[0002] China is the main origin of citrus, and its yield and planting area rank first in the world. Citrus contains rich nutrients, so it is often processed into various citrus products such as juice, cans, fruit wine, etc. However, a variety of by-products are produced during the processing of citrus, of which the yield of citrus peel residue is the most. Due to the lack of reasonable and effective treatment methods, a large amount of citrus peel residue is randomly discarded, causing serious resource waste and environmental pollution problems. Citrus peel residue is rich in flavonoids, polysaccharides, alkaloids and other active ingredients, and has antibacterial, anti-inflammatory, antitumor and other pharmacological effects. Among them, insoluble dietary fiber is the main component of citrus peel residue, and research has found that it has the effects of promoting gastrointestinal peristalsis, reducing blood sugar, regulating lipid metabolism, preventing cardiovascular and cerebrovascular diseases, etc., and has deep processing and development prospects.

[0003] Pickering emulsion is a special emulsion prepared by using solid particles with amphiphilic properties as emulsifiers. It has good biocompatibility, high stability, potential environmental stimulus responsiveness, and can realize the targeted delivery of target components, and has great application potential in the fields of food, cosmetics, drugs, etc. The widely used solid emulsifiers mainly include inorganic particles such as titanium dioxide, silicon dioxide, graphene oxide, etc., but they have the disadvantages of high cost and food safety risks, etc. Therefore, the development of food-grade solid emulsifiers (polysaccharides, proteins, etc.) from natural biopolymers has gradually become a hot spot. Insoluble dietary fiber is a polysaccharide composed of cellulose, hemicellulose and lignin, which can improve the stability of the emulsion by enhancing the interfacial adsorption and the interaction between particles, preventing droplet collision and coalescence. Therefore, it is extremely feasible to develop food-grade solid emulsifiers from insoluble dietary fiber resources such as citrus peel residue and other pomace.

[0004] Compared with other types of insoluble dietary fiber, citrus peel insoluble dietary fiber has higher total cellulose content, stronger oil and water holding capacity and adsorption performance, but the structure of citrus peel insoluble dietary fiber is firm and flat, and the hydrophilicity is high, so the emulsion prepared directly as an emulsifier has poor stability and low loading rate, and therefore it is necessary to appropriately treat the insoluble dietary fiber to change its physicochemical properties and improve the emulsifying capacity. At present, a variety of modification methods of insoluble dietary fiber have been developed, such as ball milling, ultrasonic treatment, acid and alkali treatment, cooking and enzymolysis, but these methods or equipment require high requirements, high energy consumption and high cost, or are easy to cause environmental pollution, resulting in limited application. Microbial fermentation is a modern biological modification method with mild conditions and green safety, and the hydrolytic enzymes secreted by microorganisms can effectively destroy the fiber structure of insoluble dietary fiber, so that the inside becomes loose and the surface becomes more porous, which not only improves the adsorption performance and emulsifying capacity of insoluble dietary fiber, but also improves the cholesterol, glucose and cholate adsorption capacity, and the nutritional value is significantly enhanced. However, there is no report on the fermentation modification strategy of citrus peel residue insoluble dietary fiber, and further development is needed.

[0005] In addition, it is found that the emulsion prepared by a single type of solid emulsifier has poor environmental tolerance, and the use of complex solid emulsifiers formed by the interaction between different solid particles (such as electrostatic adsorption, van der Waals force, covalent bonding, etc.) is expected to be an effective way to solve this problem. The Maillard reaction can occur between the amino group of protein and the carbonyl group of reducing sugar, and the protein and polysaccharide can be covalently combined to form a stable complex, but the surface of citrus peel residue insoluble dietary fiber contains very little reducing sugar, and the combination efficiency of protein and insoluble dietary fiber is poor, so how to improve the reducing sugar content on the surface of citrus peel residue insoluble dietary fiber becomes the key to solving the problem.

[0006] In summary, there are still many problems to be explored in the development of emulsion using citrus peel residue insoluble dietary fiber. Therefore, it is urgent to develop a new method for preparing citrus peel residue insoluble dietary fiber emulsion to improve the performance and nutritional value of the emulsion, realize the high-value conversion of citrus peel residue, and promote its popularization and application in the fields of food, cosmetics and medicine. SUMMARY

[0007] The primary purpose of the present application is to overcome the shortcomings and deficiencies of the prior art, and to provide a preparation method of functional emulsion of fermented citrus peel residue insoluble dietary fiber.

[0008] Another purpose of the present application is to provide a functional emulsion of fermented citrus peel residue insoluble dietary fiber obtained by the above preparation method.

[0009] Still another purpose of the present application is to provide the application of the above functional emulsion of fermented citrus peel residue insoluble dietary fiber.

[0010] The application is achieved by the technical scheme that a preparation method of a functional emulsion of fermented citrus pomace insoluble dietary fiber, comprising the following steps:

[0011] (1) soaking and cleaning the citrus pomace, drying, sterilizing, and obtaining a solid-state fermentation medium;

[0012] (2) adding a compound probiotic bacterial solution to the solid-state fermentation medium obtained in step (1), and performing solid-state fermentation, and then drying to obtain fermented citrus pomace;

[0013] (3) adding the fermented citrus pomace obtained in step (2) to a compound enzyme solution, adjusting the pH to obtain an enzyme hydrolysis system, and performing enzyme hydrolysis, and then centrifuging the enzyme hydrolysis solution, collecting and drying the precipitate to obtain fermented citrus pomace insoluble dietary fiber;

[0014] (4) mixing the fermented citrus pomace insoluble dietary fiber obtained in step (3) with a protein solution, adjusting the pH, and heating to obtain a fermented citrus pomace insoluble dietary fiber-protein complex;

[0015] (5) mixing the fermented citrus pomace insoluble dietary fiber-protein complex obtained in step (4) with an oil phase, ultrasonic emulsification to obtain a primary emulsion; and mixing the primary emulsion with a chitosan solution, shear emulsification to obtain a fermented citrus pomace insoluble dietary fiber functional emulsion.

[0016] The citrus pomace in step (1) is pomace separated after extracting functional components from fresh citrus peels or any year's dried citrus peels with water or an organic solvent.

[0017] The organic solvent is preferably ethanol.

[0018] The cleaning method in step (1) is to immerse in tap water or purified water at room temperature to 60 DEG C, air bubbling bath for 10-20 min, and then continue to rinse for 1-10 min under air bubbling bath; preferably, immerse in tap water or purified water at room temperature to 40 DEG C, air bubbling bath for 15 min, and then continue to rinse for 5-15 min under air bubbling bath.

[0019] The drying condition in step (1) is to dry at 40-60 DEG C to constant weight.

[0020] The sterilization condition in step (1) is preferably sterilized at 115-121 DEG C for 15-20 min.

[0021] The compound probiotic liquid mentioned in step (2) is obtained by combining Monascus purpureus seed liquid, Lactobacillus plantarum seed liquid, Bacillus amyloliquefaciens seed liquid and Bacillus subtilis seed liquid; preferably, it is composed of Monascus purpureus seed liquid, Lactobacillus plantarum seed liquid, Bacillus amyloliquefaciens seed liquid and Bacillus subtilis seed liquid in a volume ratio of 1-4:1-2:1-3:1-3; more preferably, it is combined in a volume ratio of 1-3:1-2:1-2:3; most preferably, it is combined in a volume ratio of 2:1:1:2.

[0022] The preferred concentration of the Monascus purpureus seed solution is 3 × 10⁻⁶. 7 ~3×10 10 CFU / mL; more preferably 3×10 9 CFU / mL.

[0023] The preferred Monascus ruber strain is Monascus ruber WQ15, with accession number CGMCC No. 10910, which was deposited on July 2, 2015, at the China General Microbiological Culture Collection Center located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing. This strain has been disclosed in Chinese invention patent “CN201510449543.6 - A Monascus ruber strain producing high levels of extracellular yellow pigment and its breeding method and application”.

[0024] The preferred concentration of the *Lactobacillus plantarum* seed solution is 1 × 10⁻⁶. 7 ~1×10 10 / mL; more preferably 1×10 9 CFU / mL.

[0025] The preferred Lactobacillus plantarum is Lactobacillus plantarum CGMCC1.3919.

[0026] The preferred concentration of the Bacillus amyloliquefaciens seed solution is 1×10⁻⁶. 7 ~1×10 10 / mL; more preferably 1×10 9 CFU / mL.

[0027] The preferred Bacillus amyloliquefaciens is Bacillus amyloliquefaciens CGMCC 1.398.

[0028] The preferred concentration of the Bacillus subtilis seed solution is 2 × 10⁻⁶. 7 ~2×10 10 / mL; more preferably 2×10 9 CFU / mL.

[0029] The Bacillus subtilis is preferably Bacillus subtilis CGMCC 1.837.

[0030] The Monascus seed liquid is prepared by the following steps: inoculating Monascus spores into liquid seed culture medium A, culturing at 26-30°C and 120-200 rpm for 20-24 hours to obtain the Monascus seed liquid; preferably by the following steps: inoculating Monascus spores into liquid seed culture medium A, culturing at 28°C and 150 rpm for 24 hours to obtain the Monascus seed liquid.

[0031] The liquid seed culture medium A is composed of 3 g / L of yeast extract, 20 g / L of glucose, 10 g / L of peptone, 0.5 g / L of potassium chloride, 0.01 g / L of ferrous sulfate and 4 g / L of potassium dihydrogen phosphate, and the solvent is water.

[0032] The Lactobacillus plantarum seed liquid is prepared by the following steps: inoculating Lactobacillus plantarum into sterilized liquid seed culture medium B, culturing at 33-37°C and 120-200 rpm for 18-24 hours to obtain the Lactobacillus plantarum seed liquid; preferably by the following steps: inoculating Lactobacillus plantarum into sterilized liquid seed culture medium B, culturing at 35°C and 150 rpm for 24 hours to obtain the Lactobacillus plantarum seed liquid.

[0033] The liquid seed culture medium B is MRS broth medium.

[0034] The Bacillus amyloliquefaciens seed liquid is prepared by the following steps: inoculating Bacillus amyloliquefaciens into sterilized liquid seed culture medium C, culturing at 28-32°C and 150-200 rpm for 18-24 hours to obtain the Bacillus amyloliquefaciens; preferably by the following steps: inoculating Bacillus amyloliquefaciens into sterilized liquid seed culture medium C, culturing at 30°C and 180 rpm for 20 hours to obtain the Bacillus amyloliquefaciens.

[0035] The liquid seed culture medium C is LB medium.

[0036] The Bacillus subtilis seed liquid is prepared by the following steps: inoculating Bacillus subtilis into sterilized liquid seed culture medium C, culturing at 28-32°C and 150-200 rpm for 18-24 hours to obtain the Bacillus subtilis seed liquid; preferably by the following steps: inoculating Bacillus subtilis into sterilized liquid seed culture medium C, culturing at 30°C and 180 rpm for 20 hours to obtain the Bacillus subtilis seed liquid.

[0037] The concentration of the seed liquid can be adjusted by adjusting the inoculation amount, adjusting the culture time, or adding and removing the medium in the final seed liquid.

[0038] The volume (mL) of the inoculation amount of the complex probiotic bacteria liquid in step (2) is 40% to 60% of the mass (g) of the solid-state fermentation medium; more preferably 50%.

[0039] The conditions of the solid-state fermentation in step (2) are preferably 25 to 35°C and 60 to 80% humidity for 5 to 10 days; more preferably 30°C and 70% humidity for 8 days.

[0040] The drying method in step (2) is at least one of drying at 40 to 60°C, drying below 60°C under vacuum or dehumidification, and freeze-drying.

[0041] The drying degree in step (2) is drying until a constant weight.

[0042] The complex enzyme in step (3) is composed of α-amylase, starch glucosidase, and neutral protease; preferably composed of α-amylase, starch glucosidase, and neutral protease in a mass ratio of 1 to 5: 1 to 2: 1 to 4; more preferably compounded in a mass ratio of 1 to 2: 1 to 2: 1 to 2; most preferably compounded in a mass ratio of 1: 1: 2.

[0043] The α-amylase has an enzyme activity of 4 x 10 4 U / g of α-amylase.

[0044] The starch glucosidase has an enzyme activity of 1 x 10 5 U / g of starch glucosidase.

[0045] The neutral protease has an enzyme activity of 1 x 10 5 U / g of neutral protease.

[0046] The concentration of the complex enzyme solution in step (3) is preferably 0.01% to 0.05% (w / v); more preferably 0.03% (w / v).

[0047] The added mass of the complex enzyme in step (3) is preferably calculated as 0.1% to 0.5% (w / w) of the mass of the citrus peel residue; more preferably calculated as 0.2% to 0.3% (w / w) of the mass of the citrus peel residue.

[0048] The pH in step (3) is preferably 6.0 to 7.0.

[0049] The pH adjusting agent in step (3) is preferably at least one of sodium bicarbonate and citric acid.

[0050] The enzymatic hydrolysis in step (3) is preferably carried out at 40-60°C for 90-150 min; more preferably, at 50-55°C for 100-120 min.

[0051] The centrifugation in step (3) is preferably carried out at 6000-8000 rpm for 5-10 min; more preferably, at 6000-8000 rpm for 5 min.

[0052] The drying in step (3) is at least one of drying at 40-60°C, vacuum or dehumidification drying below 60°C, and freeze drying.

[0053] The protein in step (4) is preferably at least one of soy protein isolate, pea protein isolate, whey protein isolate, and bovine serum albumin; more preferably, whey protein isolate.

[0054] The concentration of the protein solution in step (4) is preferably 1-5% (w / v); more preferably, 2-3% (w / v).

[0055] The amount of the protein solution in step (4) is preferably calculated according to the mass ratio of fermented citrus dreg insoluble dietary fiber: protein = 1-2: 2-5; more preferably, according to the mass ratio of fermented citrus dreg insoluble dietary fiber: protein = 1:2.

[0056] The mixing in step (4) is preferably carried out at 300-500 rpm for 1-3 h; more preferably, at 400 rpm for 2 h.

[0057] The pH in step (4) is preferably 8.0-9.0.

[0058] The pH adjusting agent in step (4) is preferably at least one of sodium bicarbonate and citric acid.

[0059] The heating in step (4) is preferably carried out at 80-95°C for 2-4 h; more preferably, at 90°C for 3 h.

[0060] The oil phase in step (5) is obtained by compounding edible oil, essential oil, and flavonoid ingredients; preferably, edible oil, essential oil, and flavonoid ingredients are compounded according to the mass ratio of 0-2: 0-2: 0-0.002, wherein, at most, only one ingredient is 0; more preferably, according to the mass ratio of 1: 1-2: 0-0.002; most preferably, according to the mass ratio of 1: 1: 0.002.

[0061] The edible oil is at least one of vegetable oil or animal oil; preferably at least one of soybean oil, peanut oil, rapeseed oil, lard, tallow and fish oil; more preferably soybean oil.

[0062] The essential oil is citrus fruit peel essential oil; preferably orange peel essential oil.

[0063] The flavonoid component is at least one of citrus fruit peel flavonoid components; preferably at least one of hesperidin, nobiletin and tangeritin.

[0064] The fermented citrus peel residue insoluble dietary fiber-protein complex in step (5) and the oil phase are preferably mixed at a volume ratio of 1:0.1-0.4; more preferably at a volume ratio of 1:0.3-0.4.

[0065] The ultrasonic emulsification conditions in step (5) are preferably ultrasonic power 50-120 W, ultrasonic time 10-30 min, and ultrasonic temperature 4℃-room temperature; more preferably ultrasonic power 100 W, ultrasonic time 15 min, and ultrasonic temperature 4℃.

[0066] The concentration of the chitosan solution in step (5) is preferably 0.1%-0.3% (w / v); more preferably 0.2% (w / v).

[0067] The solvent of the chitosan solution in step (5) is preferably 2%-5% (v / v) acetic acid solution; more preferably 2% (v / v) acetic acid solution.

[0068] The primary emulsion in step (5) and the chitosan solution are preferably mixed at a volume ratio of 1-5:1-2; more preferably at a volume ratio of 1-3:1.

[0069] The shearing conditions in step (5) are preferably rotation speed 10000-15000 rpm and emulsification time 30-90 s; more preferably rotation speed 12000 rpm and emulsification time 45 s.

[0070] The room temperature of the present application refers to 10-35℃; preferably 20-30℃; more preferably 24-26℃.

[0071] A fermented citrus peel residue insoluble dietary fiber functional emulsion is obtained by the above preparation method.

[0072] The above fermented citrus peel residue insoluble dietary fiber functional emulsion is applied in food, cosmetics and drugs.

[0073] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0074] (1) The present application scientifically utilizes Monascus, Lactobacillus plantarum, Bacillus amyloliquefaciens and Bacillus subtilis mixed fermentation to modify insoluble dietary fiber of citrus peel residue for the first time, and prepares functional emulsion, realizes high-value conversion of citrus peel residue, solves the problems of waste of citrus peel residue resources and serious environmental pollution, and enriches the deep processing technology of citrus peel residue.

[0075] (2) The stability, environmental tolerance and emulsifying ability of the complex formed by the fermentation modified insoluble dietary fiber of citrus peel residue and protein through Maillard reaction are significantly enhanced, and the emulsion prepared by the same has small droplets, no aggregation, long storage period, high loading rate of nutritional ingredients, excellent bioavailability and excellent antioxidant activity.

[0076] (3) Compared with the existing insoluble dietary fiber emulsion preparation method, the method proposed by the present application is simple, does not use organic reagents, and is green and efficient. The microorganisms used in the present application are all edible probiotic agents, and there is no food safety risk.

[0077] (4) The selection of microbial strains in the present application is scientific according to the composition of citrus peel residue and the purpose requirement. The citrus peel residue has a high concentration of organic acid and an overall acidic environment, which can inhibit microbial growth and reduce fermentation effect. The present application effectively modifies the insoluble dietary fiber of citrus peel residue by optimizing the strain combination, so that it is easy to react with the free amino groups on the surface of protein through Maillard reaction to form a stable insoluble dietary fiber-protein covalent complex. When used as an emulsifier, more protein on the surface and the stable structure enable the fermented insoluble dietary fiber-protein covalent complex of citrus peel residue to encapsulate more oil phase, improve the embedding efficiency of active ingredients, and enhance the storage stability and thermal stability of the emulsion. Further, the double emulsion is formed by wrapping chitosan on the outer layer of the primary emulsion, which enhances the tolerance of the emulsion to acidic environment, so that it will not be broken when passing through the stomach environment, and then successfully delivers the nutritional ingredients to the intestinal environment, improving the bioavailability of the nutritional ingredients. In addition, the fermentation modification exposes more hydroxyl groups on the surface of the insoluble dietary fiber, enhancing the antioxidant activity of the emulsion. In summary, the preparation method of the fermented insoluble dietary fiber functional emulsion of citrus peel residue proposed by the present application can effectively solve the problems of poor emulsion stability, easy aggregation, low encapsulation efficiency, poor bioavailability of nutritional ingredients and the like. BRIEF DESCRIPTION OF DRAWINGS

[0078] Figure 1 is the emulsification index (storage stability) result graph of the emulsion in different examples and comparative examples.

[0079] Figure 2 is the particle size result graph of the emulsion in different examples and comparative examples.

[0080] Figure 3is the graph of antioxidant activity results of emulsions in different examples and comparative examples; where A is ·O2 - radical scavenging activity, B is -OH radical scavenging activity. DETAILED DESCRIPTION

[0081] The application will be further described in conjunction with the examples and the accompanying drawings, but the embodiments of the application are not limited thereto.

[0082] The reagents and methods involved in the examples are all common reagents and methods in the art, unless otherwise specified, and any non-essential changes and substitutions made by those skilled in the art on the basis of the present application shall fall within the scope of the present application.

[0083] (1) Preparation of microbial seed liquid

[0084] Red Monascus (Monascus ruber) WQ 15 (preserved number CGMCC No. 10910) was inoculated into liquid medium A and cultured at 28°C with shaking at 150 rpm for 24 h to obtain a red Monascus seed liquid with a concentration of 3 x 10 9 CFU / mL. The formula of liquid medium A is: yeast extract 3 g / L, glucose 20 g / L, peptone 10 g / L, potassium chloride 0.5 g / L, ferrous sulfate 0.01 g / L, and potassium dihydrogen phosphate 4 g / L, and distilled water was added to 1 L.

[0085] Lactobacillus plantarum CGMCC 1.3919 (available from the China General Microbiological Culture Collection Center) was inoculated into liquid medium B and cultured at 35°C with shaking at 150 rpm for 24 h to obtain a Lactobacillus plantarum seed liquid with a concentration of 1 x 10 9 / mL. The formula of liquid medium B is MRS broth medium.

[0086] Bacillus amyloliquefaciens CGMCC 1.398 (available from the China General Microbiological Culture Collection Center) was inoculated into liquid medium C and cultured at 30°C with shaking at 180 rpm for 20 h to obtain a Bacillus amyloliquefaciens seed liquid with a concentration of 1 x 10 9 / mL. The formula of liquid medium C is LB medium.

[0087] Bacillus subtilis CGMCC 1.837 (available from China General Microbiological Culture Collection Center) was inoculated into liquid medium C and cultured at 30°C, 180 rpm for 20 h to obtain Bacillus subtilis seed liquid with a concentration of 2 x 10 9 / mL.

[0088] (2) Materials

[0089] The enzyme activity of alpha-amylase was 4 x 10 4 U / g (Shanghai Maikelin Biochemical Technology Co., Ltd.);

[0090] The enzyme activity of amyloglucosidase was 1 x 10 5 U / g (Shanghai Yuanye Biotechnology Co., Ltd.);

[0091] The enzyme activity of neutral protease was 1 x 10 5 U / g (Shanghai Maikelin Biochemical Technology Co., Ltd.).

[0092] Example 1

[0093] 10 g of citrus peel residue remaining after boiling water extraction for 30 min to extract active ingredients, immersed in tap water or pure water at 25-40 °C for 15 min in an air bubbling bath, then continue to rinse for 5 min in the air bubbling bath, and then dried at 50 °C to constant weight, to obtain citrus peel residue 1; sterilize the citrus peel residue 1 at 121 °C for 20 min to obtain a solid-state fermentation medium 1; mix red mold, lactobacillus plantarum, bacillus amyloliquefaciens and bacillus subtilis seed liquids in a ratio of 2:1:1:2 by volume to obtain a compound probiotic bacteria liquid 1; inoculate the compound probiotic bacteria liquid 1 into the solid-state fermentation medium 1 at an inoculation amount of 50% (v / w), mix well, and ferment at 30 °C and 70% humidity for 8 days, then take out and dry at 50 °C to obtain fermented citrus peel residue 1; prepare a compound enzyme 1 (obtained by mixing α-amylase, starch glucosidase and neutral protease in a mass ratio of 1:1:2) at a concentration of 0.03% (w / v), mix it with the fermented citrus peel residue 1, and the final addition amount of the compound enzyme 1 is 0.3% (w / w) of the mass of the fermented citrus peel residue 1, then adjust the pH to 7.0 with sodium bicarbonate solution, and enzymolysis at 50 °C for 100 min to obtain an enzymolysis product 1; centrifuge the enzymolysis product 1 at 8000 rpm for 5 min, collect the precipitate, and dry at 50 °C to obtain fermented citrus peel residue insoluble dietary fiber 1; prepare a whey protein isolate solution at a concentration of 2% (w / v), add fermented citrus peel residue insoluble dietary fiber 1 (the mass ratio of fermented citrus peel residue insoluble dietary fiber to whey protein isolate is 1:2), mix well under stirring at 400 rpm for 2 h, adjust the pH to 9.0 with sodium bicarbonate solution, and react at 90 °C for 3 h to obtain fermented citrus peel residue insoluble dietary fiber-protein complex 1; mix soybean oil, citrus peel essential oil and hesperidin in a mass ratio of 1:1:0.002 to obtain a compound oil phase 1; mix the fermented citrus peel residue insoluble dietary fiber-protein complex 1 and the compound oil phase 1 in a volume ratio of 1:0.3, ultrasonic at 100 W and 4 °C for 15 min to obtain a primary emulsion 1; prepare a chitosan solution (solvent is 2% (v / v) acetic acid solution) at a concentration of 0.2% (w / v) (chitosan is purchased from Shanghai Aladdin Bio-Chem Technology Co., Ltd., degree of deacetylation ≥95%, viscosity 100-200 mpa.s, same below), mix the primary emulsion and the chitosan solution in a volume ratio of 2:1, high-speed shear emulsify at 12000 rpm for 45 s to obtain fermented citrus peel residue insoluble dietary fiber functional emulsion 1.

[0094] Example 2

[0095] The 10-year-old dried orange peel residue 10g left after 70% (v / v) ethanol solution extraction at 60℃ for 30min, was immersed in tap water or purified water at 25-40℃ for 10min in an air-bubble bath, then washed for another 10min in the air-bubble bath, and then dried at 50℃ to constant weight to obtain dried orange peel residue 2; the dried orange peel residue 2 was sterilized at 121℃ for 20min to obtain solid-state fermentation medium 2; red yeast, lactobacillus plantarum, bacillus amyloliquefaciens and bacillus subtilis seed liquids were mixed in a ratio of 3:1:1:3 by volume to obtain a compound probiotic bacteria liquid 2; the compound probiotic bacteria liquid 2 was inoculated into the solid-state fermentation medium 2 at an inoculation amount of 40% (v / w), mixed well, and then fermented at 30℃ and 70% humidity for 10 days, and then dried at 50℃ to obtain fermented dried orange peel residue 2; a compound enzyme 2 (obtained by mixing α-amylase, amyloglucosidase and neutral protease in a mass ratio of 1:1:1) was prepared at a concentration of 0.04% (w / v), mixed with the fermented dried orange peel residue 2, and the final amount of the compound enzyme 2 added was 0.3% (w / w) of the mass of the dried orange peel residue, then the pH was adjusted to 7.0 with sodium bicarbonate solution, and then the mixture was enzymolyzed at 55℃ for 120min to obtain an enzymolyzed product 2; the enzymolyzed product 2 was centrifuged at 8000rpm for 5min, the precipitate was collected, and then dried at 50℃ to obtain fermented dried orange peel residue insoluble dietary fiber 2; a whey protein isolate solution was prepared at a concentration of 3% (w / v), and the fermented dried orange peel residue insoluble dietary fiber 2 (the mass ratio of the fermented dried orange peel residue insoluble dietary fiber to the protein was 1:2) was added, the mixture was stirred at 400rpm for 2h, the pH was adjusted to 9.0 with sodium bicarbonate solution, and then the mixture was reacted at 90℃ for 2.5h to obtain fermented dried orange peel residue insoluble dietary fiber-protein complex 2; a compound oil phase 2 was obtained by mixing lard, dried orange peel essential oil and hesperidin in a mass ratio of 1:2:0.002; the fermented dried orange peel residue insoluble dietary fiber-protein complex 2 and the compound oil phase 2 were mixed in a volume ratio of 1:0.3, and then ultrasonic treatment was performed at 100W and 4℃ for 20min to obtain a primary emulsion 2; a chitosan solution (solvent: 2% acetic acid solution) was prepared at a concentration of 0.1% (w / v), the primary emulsion and the chitosan solution were mixed in a volume ratio of 3:1, and then high-speed shearing emulsification was performed at 12000rpm for 60s to obtain fermented dried orange peel residue insoluble dietary fiber functional emulsion 2.

[0096] Example 3

[0097] The 70% (v / v) ethanol solution was selected to extract the 10 g of the 3-year-old dried citrus peel residue at 60°C for 30 min. The dried citrus peel residue 3 was immersed in tap water or purified water at 25-40°C for 15 min in an air-bubble bath, and then washed for another 5 min in the air-bubble bath. The dried citrus peel residue 3 was then dried at 50°C to a constant weight. The dried citrus peel residue 3 was sterilized at 121°C for 20 min to obtain the solid-state fermentation medium 3. The seed liquid of the Monascus, Lactobacillus plantarum, Bacillus amyloliquefaciens, and Bacillus subtilis was mixed at a volume ratio of 1:1:1:1 to obtain the compound probiotic bacteria liquid 3. The compound probiotic bacteria liquid 3 was inoculated into the solid-state fermentation medium 3 at an inoculation amount of 60% (v / w), and then mixed. The mixture was fermented at 28°C and a humidity of 70% for 10 days. The fermented dried citrus peel residue 3 was obtained by drying the mixture at 50°C. The compound enzyme 3 (obtained by mixing α-amylase, amyloglucosidase, and neutral protease at a mass ratio of 2:2:1) was prepared at a concentration of 0.05% (w / v), and then mixed with the fermented dried citrus peel residue 3. The final addition amount of the compound enzyme 3 was 0.3% (w / w) of the mass of the dried citrus peel residue. Then, the pH was adjusted to 7.0 by using a sodium bicarbonate solution, and the mixture was enzymolyzed at 55°C for 100 min to obtain the enzymolyzed product 3. The enzymolyzed product 3 was centrifuged at 8000 rpm for 5 min, and the precipitate was collected and dried at 50°C to obtain the fermented dried citrus peel residue insoluble dietary fiber 3. A whey protein isolate solution was prepared at a concentration of 5% (w / v), and then the fermented dried citrus peel residue insoluble dietary fiber 3 (the mass ratio of the fermented dried citrus peel residue insoluble dietary fiber to the protein was 1:1) was added. The mixture was stirred at 400 rpm for 2 h, and then the pH was adjusted to 9.0 by using a sodium bicarbonate solution. The mixture was reacted at 90°C for 3 h to obtain the fermented dried citrus peel residue insoluble dietary fiber-protein complex 3. The compound oil phase 2 was obtained by mixing soybean oil, dried citrus peel essential oil, and hesperidin at a mass ratio of 1:2:0. The fermented dried citrus peel residue insoluble dietary fiber-protein complex 3 and the compound oil phase 3 were mixed at a volume ratio of 1:0.3, and then ultrasonic treatment was performed on the mixture at 60W and 20°C for 30 min to obtain the primary emulsion 3. A chitosan solution (the solvent was 3% (v / v) acetic acid solution) was prepared at a concentration of 0.2% (w / v). The primary emulsion and the chitosan solution were mixed at a volume ratio of 2:1, and then high-speed shearing emulsification was performed on the mixture at 14000 rpm for 30 s to obtain the fermented dried citrus peel residue insoluble dietary fiber functional emulsion 3.

[0098] Example 4

[0099] The 10 g of 5-year-old dried tangerine peel residue left after boiling water extraction for 30 min was immersed in tap water or pure water at 25-40 °C for 20 min in an air bubbling bath, and then washed for another 10 min in the air bubbling bath, followed by drying at 50 °C until constant weight to obtain tangerine peel residue 4; the tangerine peel residue 4 was sterilized at 121 °C for 20 min to obtain a solid-state fermentation medium 4; the seed liquids of Monascus, Lactobacillus plantarum, Bacillus amyloliquefaciens and Bacillus subtilis were mixed in a ratio of 3:2:2:3 by volume to obtain a compound probiotic bacteria liquid 4; the compound probiotic bacteria liquid 4 was inoculated into the solid-state fermentation medium 4 at an inoculation amount of 60% (v / w), mixed uniformly, and then fermented at 30 °C and 70% humidity for 7 days, followed by drying at 50 °C to obtain fermented tangerine peel residue 4; a compound enzyme 4 (obtained by mixing α-amylase, amyloglucosidase and neutral protease in a mass ratio of 2:1:1) was prepared at a concentration of 0.03% (w / v), mixed with the tangerine peel residue 4, and the final addition amount of the compound enzyme 4 was 0.2% (w / w) of the mass of the tangerine peel residue, followed by adjusting the pH to 7.0 with sodium bicarbonate solution, and then enzymolysis at 50 °C for 120 min to obtain an enzymolysis product 4; the enzymolysis product 4 was centrifuged at 8000 rpm for 5 min, and the precipitate was collected and dried at 50 °C to obtain fermented tangerine peel residue insoluble dietary fiber 4; a whey protein isolate solution was prepared at a concentration of 3% (w / v), and the fermented tangerine peel residue insoluble dietary fiber 4 (the mass ratio of fermented tangerine peel residue insoluble dietary fiber to protein was 1:3) was added, mixed uniformly at 400 rpm for 2 h, and then the pH was adjusted to 9.0 with sodium bicarbonate solution, and then reacted at 90 °C for 3 h to obtain a fermented tangerine peel residue insoluble dietary fiber-protein complex 4; a compound oil phase 4 was obtained by mixing soybean oil, dried tangerine peel essential oil and hesperidin in a mass ratio of 1:0:0.002; the fermented tangerine peel residue insoluble dietary fiber-protein complex 4 and the compound oil phase 4 were mixed uniformly in a volume ratio of 1:0.4, and then ultrasonic treatment was performed at 120 W and 4 °C for 20 min to obtain a primary emulsion 4; a chitosan solution (solvent: 2% (v / v) acetic acid solution) was prepared at a concentration of 0.1% (w / v), and the primary emulsion and the chitosan solution were mixed uniformly in a volume ratio of 1:1, and then high-speed shearing emulsification was performed at 10000 rpm for 50 s to obtain a fermented tangerine peel residue insoluble dietary fiber functional emulsion 4.

[0100] Comparative Example 1

[0101] The same as Example 1, except that an equal amount of sterile water was used instead of the compound probiotic bacteria liquid.

[0102] The citrus peel residue 1 was obtained by the following steps: 10 g of citrus peel residue was left after boiling in water for 30 min to extract active ingredients, then the residue was immersed in tap water or purified water at 25-40℃ for 15 min in an air bubbling bath, and then washed for 5 min in the air bubbling bath, and then dried at 50℃ to constant weight. The citrus peel residue 1 was sterilized at 121℃ for 20 min to obtain a solid-state fermentation medium 1. The sterile water was added to the solid-state fermentation medium 1 at an inoculation amount of 50% (v / w), and then mixed uniformly, and then placed at 30℃ and 70% humidity for 8 days, and then dried at 50℃ to obtain the citrus peel residue 5. The complex enzyme 1 (obtained by mixing α-amylase, starch glucosidase and neutral protease at a mass ratio of 1:1:2) was prepared at a concentration of 0.03% (w / v), and then mixed with the citrus peel residue 5, and the final addition amount of the complex enzyme 1 was 0.3% (w / w) of the mass of the citrus peel residue, and then the pH was adjusted to 7.0 with sodium bicarbonate solution, and then the enzymolysis was carried out at 50℃ for 100 min to obtain the enzymolysis product 5. The enzymolysis product 5 was centrifuged at 8000 rpm for 5 min, and then the precipitate was collected and dried at 50℃ to obtain the citrus peel residue insoluble dietary fiber 1. The whey protein isolate solution was prepared at a concentration of 2% (w / v), and then the insoluble dietary fiber 1 (the mass ratio of insoluble dietary fiber and protein was 1:2) was added, and then mixed uniformly under stirring at 400 rpm for 2 h, and then the pH was adjusted to 9.0 with sodium bicarbonate solution, and then the reaction was carried out at 90℃ for 3 h to obtain the insoluble dietary fiber-protein complex 1. The complex oil phase 1 was obtained by mixing soybean oil, dried tangerine peel essential oil and hesperidin at a mass ratio of 1:1:0.002. The insoluble dietary fiber-protein complex and the complex oil phase 1 were mixed uniformly at a volume ratio of 1:0.3, and then ultrasonic treatment was carried out at 100 W and 4℃ for 15 min to obtain the primary emulsion 5. The chitosan solution (solvent: 2% acetic acid solution) was prepared at a concentration of 0.2%, and then the primary emulsion and the chitosan solution were mixed uniformly at a volume ratio of 2:1, and then high-speed shearing emulsification was carried out at 12000 rpm for 45 s to obtain the insoluble dietary fiber-protein emulsion 5.

[0103] Comparative Example 2

[0104] The same as Example 1, except that the same amount of sterile water was used instead of the complex probiotic bacterial solution, and no whey protein isolate solution was added.

[0105] The citrus peel residue 1 was obtained by the following steps: 10 g of citrus peel residue was left after boiling in water for 30 min to extract active ingredients, and then immersed in tap water or purified water at 25-40 °C for 15 min in an air bubbling bath, and then washed for 5 min in the air bubbling bath, and then dried at 50 °C to constant weight. The citrus peel residue 1 was sterilized at 121 °C for 20 min to obtain a solid-state fermentation medium 1. The sterile water was added to the solid-state fermentation medium 1 at an inoculation amount of 50% (v / w), and then mixed uniformly, and then placed at 30 °C and 70% humidity for 8 days, and then dried at 50 °C to obtain the citrus peel residue 5. The compound enzyme 1 (obtained by mixing α-amylase, starch glucosidase and neutral protease at a mass ratio of 1:1:2) was prepared at a concentration of 0.03% (w / v), and then mixed with the citrus peel residue 5, and then the final addition amount of the compound enzyme 1 was 0.3% (w / w) of the mass of the citrus peel residue, and then the pH was adjusted to 7.0 with sodium bicarbonate solution, and then the enzymolysis was carried out at 50 °C for 100 min to obtain the enzymolysis product 5. The precipitate was collected by centrifugation of the enzymolysis product 5 at 8000 rpm for 5 min, and then dried at 50 °C to obtain the citrus peel residue insoluble dietary fiber 1. The insoluble dietary fiber was prepared at a concentration of 1% (w / v) with water, and then mixed uniformly at 400 rpm for 2 h, and then the pH was adjusted to 9.0 with sodium bicarbonate solution, and then the reaction was carried out at 90 °C for 3 h to obtain the insoluble dietary fiber suspension 1. The compound oil phase 1 was obtained by mixing soybean oil, citrus peel essential oil and hesperidin at a mass ratio of 1:1:0.002. The insoluble dietary fiber suspension 1 and the compound oil phase 1 were mixed uniformly at a volume ratio of 1:0.3, and then ultrasonic treatment was carried out at 100 W and 4 °C for 15 min to obtain the primary emulsion 6. The chitosan solution (solvent: 2% (v / v) acetic acid solution) was prepared at a concentration of 0.2% (w / v), and then the primary emulsion and the chitosan solution were mixed uniformly at a volume ratio of 2:1, and then high-speed shearing emulsification was carried out at 12000 rpm for 45 s to obtain the insoluble dietary fiber-protein emulsion 6.

[0106] Comparative Example 3

[0107] The same as Example 1, except that Aspergillus niger and Lactobacillus rhamnosus were used instead of Monascus and Bacillus subtilis.

[0108] The citrus peel residue left after 10 g of citrus peel was extracted with boiling water for 30 min was immersed in tap water or pure water at 25-40℃ for 15 min in an air bubbling bath, then washed for another 5 min in the air bubbling bath, and then dried at 50℃ to constant weight to obtain citrus peel residue 1; the citrus peel residue 1 was sterilized at 121℃ for 20 min to obtain a solid-state fermentation medium 1; Aspergillus niger CGMCC 3.7206 (available from the China General Microbiological Culture Collection Center), Lactobacillus plantarum, Bacillus amyloliquefaciens and Lactobacillus rhamnosus CGMCC 1.2467 (available from the China General Microbiological Culture Collection Center) seed liquid were mixed in a ratio of 2:1:1:2 by volume to obtain a compound probiotic bacteria liquid 5; the compound probiotic bacteria liquid 5 was inoculated into the solid-state fermentation medium 1 at an inoculation amount of 50% (v / w), mixed well, and then fermented at 30℃ and 70% humidity for 8 days, followed by drying at 50℃ to obtain fermented citrus peel residue 6; a compound enzyme 1 (obtained by mixing α-amylase, amyloglucosidase and neutral protease in a mass ratio of 1:1:2) was prepared at a concentration of 0.03% (w / v), mixed with the fermented citrus peel residue 6, the final addition amount of the compound enzyme 1 was 0.3% (w / w) of the mass of the fermented citrus peel residue, then the pH was adjusted to 7.0 with sodium bicarbonate solution, and then the enzymolysis was carried out at 50℃ for 100 min to obtain an enzymolysis product 6; the enzymolysis product 6 was centrifuged at 8000 rpm for 5 min, the precipitate was collected and dried at 50℃ to obtain fermented citrus peel residue insoluble dietary fiber 5; a whey protein isolate solution was prepared at a concentration of 2% (w / v), fermented citrus peel residue insoluble dietary fiber 5 (mass ratio of fermented citrus peel residue insoluble dietary fiber to protein 1:2) was added, mixed well under stirring at 400 rpm for 2 h, the pH was adjusted to 9.0 with sodium bicarbonate solution, and then the reaction was carried out at 90℃ for 3 h to obtain fermented citrus peel residue insoluble dietary fiber-protein complex 5; soybean oil, citrus peel essential oil and hesperidin were mixed in a mass ratio of 1:1:0.002 to obtain a compound oil phase 1; the fermented citrus peel residue insoluble dietary fiber-protein complex 5 and the compound oil phase 1 were mixed in a volume ratio of 1:0.3, and then ultrasonic treatment was carried out at 100W and 4℃ for 15 min to obtain a primary emulsion 7; a chitosan solution (solvent: 2% (v / v) acetic acid solution) was prepared at a concentration of 0.2% (w / v), the primary emulsion and the chitosan solution were mixed in a volume ratio of 2:1, and then high-speed shearing emulsification was carried out at 12000 rpm for 45 s to obtain a fermented citrus peel residue insoluble dietary fiber functional emulsion 7.

[0109] Comparative Example 4

[0110] The same as in Example 1, except that only Monascus was used for solid-state fermentation.

[0111] After 10 g of citrus peel residue was extracted with boiling water for 30 min, the residue was immersed in tap water or pure water at 25-40 °C for 15 min in an air bubbling bath, then washed for 5 min in the air bubbling bath, and then dried at 50 °C to constant weight to obtain citrus peel residue 1. The citrus peel residue 1 was sterilized at 121 °C for 20 min to obtain a solid-state fermentation medium 1. Red koji mold seed liquid was inoculated into the solid-state fermentation medium 1 at an inoculation amount of 50% (v / w), mixed, and fermented at 30 °C and 70% humidity for 8 days, and then dried at 50 °C to obtain fermented citrus peel residue 7. Compound enzyme 1 (obtained by mixing α-amylase, amyloglucosidase, and neutral protease at a mass ratio of 1:1:2) was prepared at a concentration of 0.03% (w / v), mixed with the fermented citrus peel residue 7, and the final addition amount of the compound enzyme 1 was 0.3% (w / w) of the mass of the fermented citrus peel residue. Then, the pH was adjusted to 7.0 with sodium bicarbonate solution, and the enzymatic hydrolysis was performed at 50 °C for 100 min to obtain an enzymatic hydrolysate 7. The enzymatic hydrolysate 7 was centrifuged at 8000 rpm for 5 min, and the precipitate was collected and dried at 50 °C to obtain fermented citrus peel residue insoluble dietary fiber 6. Whey protein isolate solution was prepared at a concentration of 2%, and fermented citrus peel residue insoluble dietary fiber 6 (mass ratio of fermented citrus peel residue insoluble dietary fiber to protein 1:2) was added, mixed at 400 rpm for 2 h, and the pH was adjusted to 9.0 with sodium bicarbonate solution. The reaction was performed at 90 °C for 3 h to obtain fermented citrus peel residue insoluble dietary fiber-protein complex 6. Compound oil phase 1 was obtained by mixing soybean oil, dried tangerine peel essential oil, and hesperidin at a mass ratio of 1:1:0.002. Fermented citrus peel residue insoluble dietary fiber-protein complex 6 and compound oil phase 1 were mixed at a volume ratio of 1:0.3, ultrasonicated at 100 W and 4 °C for 15 min to obtain a primary emulsion 8. Chitosan solution (solvent: 2% (v / v) acetic acid solution) was prepared at a concentration of 0.2% (w / v), and the primary emulsion and the chitosan solution were mixed at a volume ratio of 2:1, and high-speed shearing emulsification was performed at 12000 rpm for 45 s to obtain fermented citrus peel residue insoluble dietary fiber functional emulsion 8.

[0112] Comparative Example 5

[0113] The same as in Example 1, except that pectinase (purchased from Shanghai Maikelin Biochemical Technology Co., Ltd., enzyme activity 1×10 5 U / g) and lipase (purchased from Shanghai Maikelin Biochemical Technology Co., Ltd., enzyme activity 1×10 5 U / g) were used instead of α-amylase and amyloglucosidase.

[0114] The citrus peel residue 1 was obtained by the following method: 10 g of citrus peel residue was left after boiling in water for 30 min to extract active ingredients, and then immersed in tap water or pure water at 25-40℃ for 15 min in an air bubbling bath, and then washed for 5 min in the air bubbling bath, and then dried at 50℃ to constant weight. The citrus peel residue 1 was sterilized at 121℃ for 20 min to obtain a solid-state fermentation medium 1. The seed liquid of Monascus, Lactobacillus plantarum, Bacillus amyloliquefaciens and Bacillus subtilis was mixed at a volume ratio of 2:1:1:2 to obtain a compound probiotic bacteria liquid 1. The compound probiotic bacteria liquid 1 was inoculated into the solid-state fermentation medium 1 at an inoculation amount of 50% (v / v), mixed uniformly, and then fermented at 30℃ and a humidity of 70% for 8 days, and then dried at 50℃ to obtain fermented citrus peel residue 1. A compound enzyme 5 (obtained by mixing pectinase, lipase and neutral protease at a mass ratio of 1:1:2) was prepared at a concentration of 0.03% (w / v), mixed with the fermented citrus peel residue 1, and the final addition amount of the compound enzyme 5 was 0.3% (w / w) of the mass of the citrus peel residue, and then the pH was adjusted to 7.0 with sodium bicarbonate solution, and then enzymolysis was performed at 50℃ for 100 min to obtain an enzymolysis product 8. The enzymolysis product 8 was centrifuged at 8000 rpm for 5 min, and the precipitate was collected and dried at 50℃ to obtain fermented citrus peel residue insoluble dietary fiber 7. A whey protein isolate solution was prepared at a concentration of 2% (w / v), and the fermented citrus peel residue insoluble dietary fiber 7 (the mass ratio of the fermented citrus peel residue insoluble dietary fiber to the protein was 1:2) was added, and then mixed uniformly under stirring at 400 rpm for 2 h, and then the pH was adjusted to 9.0 with sodium bicarbonate solution, and then reacted at 90℃ for 3 h to obtain a fermented citrus peel residue insoluble dietary fiber-protein complex 7. A compound oil phase 1 was obtained by mixing soybean oil, dried tangerine peel essential oil and hesperidin at a mass ratio of 1:1:0.002. The fermented citrus peel residue insoluble dietary fiber-protein complex 7 and the compound oil phase 1 were mixed at a volume ratio of 1:0.3, and then ultrasonic treatment was performed at 100W and 4℃ for 15 min to obtain a primary emulsion 9. A chitosan solution (solvent: 2% (v / v) acetic acid solution) was prepared at a concentration of 0.2% (w / v), and then the primary emulsion and the chitosan solution were mixed at a volume ratio of 2:1, and then high-speed shearing emulsification was performed at 12000 rpm for 45 s to obtain a fermented citrus peel residue insoluble dietary fiber functional emulsion 9.

[0115] Comparative Example 6

[0116] The same as Example 1, except that whey protein isolate was replaced by gelatin.

[0117] The citrus peel residue 1 was obtained by the following steps: 10 g of citrus peel residue was immersed in tap water or pure water at 25-40℃ for 15 min in an air bubbling bath, then washed for 5 min in the air bubbling bath, and then dried at 50℃ to constant weight. The citrus peel residue 1 was sterilized at 121℃ for 20 min to obtain a solid-state fermentation medium 1. The seed liquid of Monascus, Lactobacillus plantarum, Bacillus amyloliquefaciens and Bacillus subtilis was mixed at a volume ratio of 2:1:1:2 to obtain a compound probiotic bacteria liquid 1. The compound probiotic bacteria liquid 1 was inoculated into the solid-state fermentation medium 1 at an inoculation amount of 50% (v / w), mixed uniformly, and then fermented at 30℃ and a humidity of 70% for 8 days. Then, the fermented citrus peel residue 1 was obtained by drying at 50℃. The compound enzyme 1 (obtained by mixing α-amylase, amyloglucosidase and neutral protease at a mass ratio of 1:1:2) was prepared at a concentration of 0.03% (w / v), mixed with the fermented citrus peel residue 1, and the final addition amount of the compound enzyme 1 was 0.3% (w / w) of the mass of the citrus peel residue. Then, the pH was adjusted to 7.0 with a sodium bicarbonate solution, and the enzymolysis was performed at 50℃ for 100 min to obtain an enzymolysis product 1. The enzymolysis product 1 was centrifuged at 8000 rpm for 5 min, and the precipitate was collected and dried at 50℃ to obtain the fermented citrus peel residue insoluble dietary fiber 1. A gelatin solution was prepared at a concentration of 2% (w / v), and the fermented citrus peel residue insoluble dietary fiber 1 (the mass ratio of the fermented citrus peel residue insoluble dietary fiber and protein was 1:2) was added and mixed uniformly at 400 rpm for 2 h. The pH was adjusted to 9.0 with a sodium bicarbonate solution, and the reaction was performed at 90℃ for 3 h to obtain the fermented citrus peel residue insoluble dietary fiber-protein complex 8. The compound oil phase 1 was obtained by mixing soybean oil, dried tangerine peel essential oil and hesperidin at a mass ratio of 1:1:0.002. The fermented citrus peel residue insoluble dietary fiber-protein complex 8 and the compound oil phase 1 were mixed uniformly at a volume ratio of 1:0.3, and the primary emulsion 10 was obtained by ultrasonic treatment at 100W and 4℃ for 15 min. The chitosan solution (solvent: 2% (v / v) acetic acid solution) was prepared at a concentration of 0.2% (w / v), and the primary emulsion and the chitosan solution were mixed uniformly at a volume ratio of 2:1, and the fermented citrus peel residue insoluble dietary fiber functional emulsion 10 was obtained by high-speed shearing emulsification at 12000 rpm for 45 s.

[0118] Detection method

[0119] (1) Dietary fiber monosaccharide analysis

[0120] Each 5 mg of dried sample of citrus dreg insoluble dietary fiber prepared in Examples 1-4 and Comparative Examples 1, 3, 4, 5 was weighed, 5 mL of trifluoroacetic acid (2 mol / L, TFA) was added, and the mixture was sealed and hydrolyzed in an oil bath at 110°C for 3 hours. The TFA was removed by rotary evaporation. The hydrolyzate was added to 500 μL of 0.3 mol / L NaOH solution. Then, 500 μL of PMP methanol solution (0.5 mol / L) was added, and the mixture was reacted at 70°C for 1 hour. After cooling, 500 μL of hydrochloric acid solution (0.3 mol / L) was added, and 1 mL of dichloromethane was added to remove PMP. The supernatant was filtered through a 0.22 μm filter membrane for detection. The liquid chromatography detection conditions were as follows: C18 column (250 x 4.6 mm, 5 μm), column temperature: 30°C, mobile phase: 0.1 mol / L phosphate buffer (pH = 6.7) / acetonitrile (83:17, V:V), flow rate: 1 mL / min, detection wavelength: 245 nm, injection volume: 20 μL.

[0121] (2) Emulsion stability index

[0122] Each 8 mL of emulsion prepared in Examples 1-4 and Comparative Examples 1-6 was poured into a 10 mL glass serum bottle, sealed, and stored at room temperature for 30 days. The emulsion phase height H e and the total emulsion system height H t were measured on the 1st day, the 15th day, and the 30th day, respectively. The stability index CI (%) = H e / H t x 100%.

[0123] (3) Encapsulation efficiency

[0124] Each 200 μL of emulsion prepared in Examples 1-4 and Comparative Examples 1-6 was mixed with 800 μL of n-hexane, and the mixture was gently shaken. The content of free unencapsulated essential oil and flavonoid in the supernatant was measured and recorded as C fe and C ff , respectively. The emulsion and n-hexane mixture were subjected to ultrasonic demulsification at 300 W for 30 min. The total content of essential oil and flavonoids in the supernatant was measured and recorded as C te and C tf , respectively. The initial content of essential oil and flavonoids before encapsulation was recorded as C ie and C if , respectively. The essential oil encapsulation efficiency EE e (%) = (C te -C fe ) / C ie x 100%; the flavonoid encapsulation efficiency EE f (%) = (C tf -C ff ) / C if x 100%.

[0125] (4) Centrifugal stability

[0126] Each 200 μL of the emulsions prepared in Examples 1 to 4 and Comparative Examples 1 to 6 was mixed with 800 μL of n-hexane, and the content of free unencapsulated essential oil and flavonoid in the supernatant was measured, and recorded as C fe and C ff The emulsion and n-hexane mixture was centrifuged at 6000 rpm for 10 min, and the content of essential oil and flavonoid released by centrifugation in the supernatant was measured, and recorded as C ce and C cf The emulsion and n-hexane mixture was subjected to ultrasonic demulsification at 300 W for 30 min, and then the total content of essential oil and flavonoid in the supernatant was measured, and recorded as C te and C tf The essential oil centrifugal stability constant K e = (C te - (C ce - C fe )) / C te x 100%; and the flavonoid essential oil centrifugal stability constant K f = (C tf - (C cf - C ff )) / C tf x 100%.

[0127] (5) Particle size analysis

[0128] An appropriate amount of the emulsion prepared in Examples 1 to 4 and Comparative Examples 1 to 6 was diluted 500 times with water, and the particle size of the emulsion was measured using a laser particle size analyzer.

[0129] (6) Antioxidant activity analysis

[0130] · O2 - radical scavenging activity: 500 μL of each of the emulsions prepared in Examples 1 to 4 and Comparative Examples 1 to 6 was mixed with 2 mL of Tris hydrochloride buffer (pH 8.2), and allowed to stand at 37°C for 20 min. Then, 0.2 mL of pyrogallol solution was added, and allowed to react at 37°C for 5 min. Finally, 0.1 mL of hydrochloric acid solution was added to terminate the reaction, and the absorbance was measured at 325 nm.

[0131] · OH radical scavenging activity: 500 μL of each of the emulsions prepared in Examples 1 to 4 and Comparative Examples 1 to 6 was mixed with 500 μL of ferrous sulfate solution (9 mmol / L), 0.5 mL of salicylic acid ethanol solution (9 mmol / L), and 0.5 mL of hydrogen peroxide (8.8 mmol / L) in sequence, and allowed to react at 37°C for 30 min, and the absorbance was measured at 510 nm.

[0132] Trolox was used as a positive control, and the results were expressed as IC 50 values, representing the sample amount required to scavenge 50% of free radicals.

[0133] (7) Bioavailability

[0134] Each 15 mL of the emulsion prepared in Examples 1-4 and Comparative Examples 1-6 was mixed with 15 mL of simulated gastric juice (2000 U / mL pepsin, 2 mg / mL NaCl), and the pH was adjusted to 2.0, and shaken at 37°C for 120 min. 1.5 mL of simulated intestinal juice (10 mmol / L CaCl2and 150 mmol / L NaCl) and 3.5 mL of bile salts (20 mg / mL) were added to the 30 mL sample after gastric digestion, the pH was adjusted to 7.0, 2.5 mL of a mixed solution containing 100 U / mL trypsin and 2000 U / mL lipase was added, and the mixture was shaken at 37°C for 120 min. The contents of essential oils and flavonoids in the initial emulsion and in the digestion solution after intestinal digestion were measured and denoted as C 初始 and C 消化后 , respectively. The bioavailability (%) was calculated as (C 初始 -C 消化后 ) / C 初始 x 100%.

[0135] Results

[0136] Table 1 summarizes the composition and content of monosaccharides in different citrus peel residue insoluble dietary fiber samples. Compared with Comparative Example 1, the content of mannose in Examples 1-4 was increased by 45%-88%, the content of galacturonic acid was increased by 2.79-4.51 times, the content of glucose was increased by 21%-52%, and the content of other monosaccharides was almost unchanged, indicating that fermentation modification can increase the proportion of monosaccharides in citrus peel residue insoluble dietary fiber, which is beneficial for subsequent combination with proteins. In addition, fermentation with other microbial combinations (Comparative Example 3) or single bacteria (Comparative Example 4) reduced the proportion of monosaccharides in citrus peel residue insoluble dietary fiber, and the effect of other complex enzyme treatment after fermentation on the increase of monosaccharide content was also significantly lower than that of the examples, indicating that the technical effects of other treatment methods on improving the composition and content of monosaccharides in citrus peel residue insoluble dietary fiber are not as good as the method proposed in the present application.

[0137] Table 1 Composition and content of monosaccharides in citrus peel residue insoluble dietary fiber

[0138]

[0139]

[0140] Figure 1The results of the storage stability analysis of the emulsions are shown. The emulsions of Examples 1-4 did not show the phenomenon of stratified aggregation for 15 days before storage; the emulsion prepared with the unmodified citrus dreg insoluble dietary fiber-protein complex emulsifier began to aggregate after 15 days and showed the phenomenon of demulsification after 30 days; the emulsion prepared with only the citrus dreg insoluble dietary fiber as the emulsifier showed slight stratification after 1 day and the emulsification index was only 75.2% after 30 days. The results show that the fermentation modification treatment of the insoluble dietary fiber and the Maillard reaction between the insoluble dietary fiber and the protein can significantly improve the storage stability of the emulsion. In addition, the emulsions obtained by the treatment methods in Comparative Examples 3-6 had emulsification indexes of only 70.2%-76.8% after 30 days of storage, and the stability was significantly lower than that of the Examples.

[0141] Table 2 shows the encapsulation effect of the emulsions on the essential oil and hesperidin and the centrifugal stability constant of the emulsion. The encapsulation rate of the essential oil of the emulsions of Examples 1-4 was 88.9%-90.5%, and the encapsulation rate of the flavonoid component hesperidin was 84.1%-86.4%, which was significantly higher than that of Comparative Example 1 and Comparative Example 2, indicating that the emulsion prepared by the method of the application had good encapsulation effect on the active ingredients. In addition, the centrifugal stability constant of the emulsions of Examples 1-4 was significantly higher than that of Comparative Example 1 and Comparative Example 2, indicating that the emulsion prepared by the method of the application had good resistance to external environmental conditions. The active ingredient encapsulation rate and centrifugal stability constant of the emulsion obtained by the treatment method in Comparative Examples 3-6 were also lower than those of the Examples, indicating that the emulsion prepared by the method of the application had stronger encapsulation effect on the active ingredients.

[0142] Table 2 shows the encapsulation rate of the emulsion on the essential oil and hesperidin and the centrifugal stability constant

[0143]

[0144]

[0145] Figure 2 The particle size of the emulsion is shown. The particle size of the emulsion of Examples 1-4 was between 42.45-48.08 μm, which was significantly lower than that of Comparative Example 1 and Comparative Example 2, indicating that the fermentation modification treatment could reduce the droplets of the emulsion, and the emulsion was more delicate and had stronger flowability. The particle size of the emulsion in Comparative Examples 3-6 was between 58.6-74.6 μm, which was higher than that of the Examples, indicating that the droplets of the emulsion prepared by the method of the application were smaller.

[0146] Figure 3 The results of the antioxidant activity of the emulsion are shown. The ·O2 - radical scavenging activity IC 50 value and the -OH radical scavenging activity IC 50The values are significantly lower than those of the comparative examples 1-6, showing stronger antioxidant capacity, because the emulsion prepared by using the fermentation modified insoluble dietary fiber-protein complex as the emulsifier has smaller particle size and stronger dispersibility, which can promote the contact of the emulsion with free radicals and improve the ability of capturing free radicals.

[0147] Table 3 shows the bioavailability results of the active ingredients loaded in the emulsion. After the simulation of gastrointestinal digestion, the bioavailability of the citrus peel essential oil and the hesperidin of the emulsions of examples 1-4 are significantly higher than those of the comparative examples 1-6, because the fermentation modified insoluble dietary fiber-protein complex in the outer layer of the emulsion has a thicker interface layer and stronger stability, the irreversible adsorption at the oil-water interface and the chitosan layer in the outer layer of the emulsion prevent the reaction between the protease, lipase, pancreatic enzyme and the active ingredients during the digestion process, so that the emulsion can successfully deliver the active ingredients to the target site and play the efficacy.

[0148] Table 3 Bioavailability of the citrus peel essential oil and the flavonoid ingredients in the emulsion

[0149] Bioavailability of perillyl alcohol Bioavailability of hesperidin Example 1 56.24％ 60.24％ Example 2 51.26％ 58.64％ Example 3 52.64％ / Example 4 / 52.78％ Comparative Example 1 38.15％ 39.68％ Comparative Example 2 25.32％ 23.68％ Comparative Example 3 32.71％ 34.87％ Comparative Example 4 28.11％ 22.67％ Comparative Example 5 41.35％ 43.17％ Comparative Example 6 40.19％ 40.22％

[0150] In summary, the present application provides a preparation method of a fermentation citrus peel residue insoluble dietary fiber functional emulsion, which selects Monascus, Lactobacillus plantarum, Bacillus amyloliquefaciens and Bacillus subtilis as mixed fermentation probiotic strains, and improves the structure of the citrus peel residue insoluble dietary fiber through solid-state fermentation, increases the surface monosaccharide content, so that it is more prone to Maillard reaction with free amino groups of proteins to form a more stable insoluble dietary fiber-protein covalent complex; the emulsion droplets prepared by using the insoluble dietary fiber-protein covalent complex as the emulsifier are smaller, the active ingredient encapsulation rate is higher, the stability is stronger, and at the same time, the emulsion has higher free radical capturing capacity and exhibits good antioxidant activity; in addition, the thicker interface layer of the insoluble dietary fiber-protein covalent complex and the chitosan layer in the outer layer of the emulsion enhance the tolerance of the emulsion under acidic conditions, which can effectively protect the active ingredients from being degraded by the gastrointestinal tract, thereby improving the bioavailability of the active ingredients.

[0151] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods, which are all included in the protection scope of the present application.

Claims

1. A method for preparing a fermented citrus albedo insoluble dietary fiber functional emulsion, characterized by It comprises the following steps: (1) Soak and clean the citrus peel residue, dry, sterilize, and obtain a solid-state fermentation medium; (2) Add a compound probiotic bacteria liquid to the solid-state fermentation medium obtained in step (1), and perform solid-state fermentation, and then dry to obtain fermented citrus peel residue; (3) Add the fermented citrus peel residue obtained in step (2) to a compound enzyme solution, adjust the pH to obtain an enzyme hydrolysis system, and then perform enzyme hydrolysis, and then centrifuge the enzyme hydrolysis liquid, collect and dry the precipitate to obtain fermented citrus peel residue insoluble dietary fiber; (4) Mix the fermented citrus peel residue insoluble dietary fiber obtained in step (3) with a protein solution, adjust the pH, and heat to obtain a fermented citrus peel residue insoluble dietary fiber-protein complex; (5) Mix the fermented citrus peel residue insoluble dietary fiber-protein complex obtained in step (4) with an oil phase, ultrasonic emulsification to obtain a primary emulsion; then mix the primary emulsion with a chitosan solution, shear emulsification to obtain a fermented citrus peel residue insoluble dietary fiber functional emulsion; The compound probiotic bacteria liquid in step (2) is composed of Monascus seed liquid, Lactobacillus plantarum seed liquid, Bacillus amyloliquefaciens seed liquid, and Bacillus subtilis seed liquid in a volume ratio of 1-4:1-2:1-3:1-3; The concentration of the Monascus seed liquid is 3×10 7 ~ 3×10 10 CFU / mL. The concentration of the Lactobacillus plantarum seed liquid is 1 x 10 7 ~1 x 10 10 / mL. The concentration of the said Bacillus amyloliquefaciens seed liquid is 1 x 10 7 ~1 x 10 10 / mL. The concentration of the said Bacillus subtilis seed liquid is 2 x 10 7 ~ 2 x 10 10 / mL. The compound enzyme in step (3) is composed of alpha-amylase, starch glucosidase, and neutral protease in a mass ratio of 1-5:1-2:1-4; The α-amylase has an enzyme activity of 4 x 10 4 U / g of α-amylase; The starch glucosidase has an enzyme activity of 1 x 10 5 U / g of starch glucosidase; The neutral protease is a neutral protease having an enzyme activity of 1 x 10 5 U / g of neutral protease.

2. The preparation method of the fermented citrus peel residue insoluble dietary fiber functional emulsion according to claim 1, characterized in that: The cleaning method in step (1) is to immerse in tap water or pure water at room temperature to 60°C, air bubbling bath for 10-20 min, and then continue to rinse for 1-10 min under air bubbling bath; The drying condition in step (1) is to dry at 40-60°C until constant weight; The sterilization condition in step (1) is to sterilize at 115-121°C for 15-20 min; The drying method in step (2) is at least one of 40-60°C drying, vacuum or dehumidification drying below 60°C, and freeze drying; The drying degree in step (2) is to dry until constant weight; The centrifugation condition in step (3) is as follows: centrifuge at 6000-8000 rpm for 5-10 min; The drying method in step (3) is at least one of 40-60°C drying, vacuum or dehumidification drying below 60°C, and freeze drying; The mixing condition in step (4) is to stir at 300-500 rpm for 1-3 h.

3. The preparation method of the fermented citrus peel residue insoluble dietary fiber functional emulsion according to claim 1, characterized in that: The pH adjusting reagent in step (3) is at least one of sodium bicarbonate and citric acid; The protein in step (4) is at least one of soybean protein isolate, pea protein isolate, whey protein isolate, and bovine serum protein isolate; The pH adjusting reagent in step (4) is at least one of sodium bicarbonate and citric acid; The oil phase in step (5) is obtained by compounding edible oil, essential oil, and flavonoid components.

4. The preparation method of the fermented citrus dreg insoluble dietary fiber functional emulsion according to claim 3, characterized in that: the oil phase in step (5) is obtained by compounding edible oil, essential oil and flavonoid components in a mass ratio of 0-2:0-2:0-0.002, wherein, at most only one component is 0; the edible oil is at least one of plant oil or animal oil; the essential oil is citrus peel essential oil; the flavonoid component is at least one of citrus peel flavonoid components.

5. The preparation method of the fermented citrus dreg insoluble dietary fiber functional emulsion according to claim 4, characterized in that: Monascus ruber The red mold mentioned is Monascus purpureus (Monascus purpureus) Lactobacillus plantarum WQ15, with accession number CGMCC No. 10910, was deposited on July 2, 2015 at the China General Microbiological Culture Collection Center, located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing. The Lactobacillus plantarum is Lactobacillus plantarum (CGMCC 1.3919); and the Lactobacillus fermentum is Lactobacillus fermentum (CGMCC 1.3918). Bacillus amyloliquefaciens ) CGMCC The Bacillus amyloliquefaciens is Bacillus amyloliquefaciens (CGMCC 1.398). Bacillus subtilis ) CGMCC 1.398; The Bacillus subtilis is Bacillus subtilis (CGMCC 1.837). the edible oil is at least one of soybean oil, peanut oil, rapeseed oil, lard, tallow and fish oil; ) CGMCC 1.837; the essential oil is dried tangerine peel essential oil; the flavonoid component is at least one of hesperidin, nobiletin and tangeritin.

6. The preparation method of the fermented citrus dreg insoluble dietary fiber functional emulsion according to claim 1, characterized in that: the volume of the inoculation amount of the compound probiotic bacteria solution in step (2) is 40%-60% of the mass of the solid-state fermentation medium; the added mass w of the compound enzyme in step (3) is 0.1%-0.5% of the mass w of the citrus dregs; the amount of the protein solution in step (4) is calculated according to the mass ratio of fermented citrus dreg insoluble dietary fiber: protein = 1-2:2-5; the fermented citrus dreg insoluble dietary fiber-protein compound and the oil phase in step (5) are mixed in a volume ratio of 1:0.1-0.4; the primary emulsion and the chitosan solution in step (5) are mixed in a volume ratio of 1-5:1-2.

7. The preparation method of the fermented citrus dreg insoluble dietary fiber functional emulsion according to claim 1, characterized in that: the concentration of the compound enzyme solution in step (3) is 0.01%-0.05% (mass / volume); the pH in step (3) is 6.0-7.0; the concentration of the protein solution in step (4) is 1%-5% (mass / volume); the pH in step (4) is 8.0-9.0; the concentration of the chitosan solution in step (5) is 0.1%-0.3% (mass / volume).

8. The preparation method of the fermented citrus dreg insoluble dietary fiber functional emulsion according to claim 1, characterized in that: the solid-state fermentation conditions in step (2) are 25-35℃ and 60-80% humidity for 5-10 days; the enzymolysis conditions in step (3) are 40-60℃ for 90-150 min; the heating conditions in step (4) are 80-95℃ for 2-4 h; ​ The ultrasonic emulsification in step (5) is performed at an ultrasonic power of 50-120 W, an ultrasonic time of 10-30 min, and an ultrasonic temperature of 4°C to room temperature. The shearing in step (5) is performed at a rotation speed of 10,000-15,000 rpm and an emulsification time of 30-90 s.

9. A fermented citrus pulp insoluble dietary fiber functional emulsion, characterized by: The functional emulsion of the fermented citrus pomace insoluble dietary fiber according to claim 9 is used in food and cosmetics.

10. The fermented citrus pomace insoluble dietary fiber functional emulsion according to claim 9 is used in food and cosmetics.

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