A stable oil-in-water emulsion utilizing by-product soybean hulls
The oil-in-water emulsion was prepared by high-pressure homogenization of soybean seed coat, which solved the problems of poor biocompatibility and environmental pollution of inorganic particles and achieved the preparation of stable emulsion and food application.
Patent Information
- Application Number
- CN202210568213.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Priority Date
- 2022-03-23
- Filing Date
- 2022-05-24
- Publication Date
- 2025-10-21
- Estimated Expiration
- 2042-05-24
AI Technical Summary
In the prior art, when preparing Pickering emulsion, inorganic particles are used as stabilizers, which has the problem of poor biocompatibility, and the cellulose extraction process requires alkaline or acidic conditions, causing environmental pollution.
Soybean seed coat, a by-product of soybean oil processing, is used as a stabilizer. An oil-in-water emulsion is prepared through high-pressure homogenization treatment, avoiding the use of chemical reagents and forming a stabilizer that works together with insoluble dietary fiber and protein.
The preparation process is environmentally friendly and pollution-free, and a stable oil-in-water emulsion is obtained. The emulsion has good storage stability and can be used in the food field to improve the nutritional value of food.
Smart Images
Figure CN116831268B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of sustainable utilization of natural materials and oil-in-water emulsions, and particularly relates to an oil-in-water emulsion stabilized by utilizing by-product soybean seed coat. Background Art
[0002] In recent years, Pickering emulsions stabilized by solid particles have received widespread attention from researchers. Compared with emulsions stabilized by traditional surfactants, Pickering emulsions have long-term stability and can replace emulsions stabilized by chemical surfactants in applications such as food, cosmetics, and pharmaceuticals. The solid particles that stabilize Pickering emulsions mainly include inorganic particles (silicon dioxide) and biogenic natural substances (polysaccharides, proteins). However, inorganic particles have poor biocompatibility, which limits the application of Pickering emulsions in other fields such as food. Biogenic natural particles have good biocompatibility and biodegradability, and there is a great trend to develop new Pickering particles based on bio-based particles.
[0003] The development of new Pickering particles from food processing waste and byproducts is of great interest to many researchers. Currently, many researchers have extracted cellulose from food waste materials such as ginkgo nut shells, sweet potato residue, pineapple peel residue, and soybean dregs to produce Pickering particles with excellent emulsifying properties. This not only improves environmental benefits but also increases their added value. However, the extraction of these celluloses typically requires alkaline or acidic conditions, which inevitably generates large amounts of wastewater, causing environmental pollution or increasing wastewater treatment costs. Summary of the Invention
[0004] The present invention aims to provide an oil-in-water emulsion. The oil-in-water emulsion uses a suspension prepared by high-pressure homogenization of soybean seed hulls, a by-product of soybean oil processing, as a stabilizer. The stabilizer can be prepared only by high-pressure homogenization. The preparation process does not use chemical reagents for purification or purification, does not generate wastewater or other pollutants, is environmentally friendly, and has emulsification functionality.
[0005] The technical solution adopted by the present invention is:
[0006] The invention discloses an oil-in-water emulsion stabilized by using soybean husk as a by-product. The soybean husk is crushed and sieved to obtain soybean husk powder, which is then dispersed in deionized water and subjected to high-pressure homogenization to obtain a soybean husk suspension. The soybean husk suspension is mixed with an oil phase and subjected to high-speed shear dispersion and high-pressure homogenization to obtain a stable oil-in-water emulsion.
[0007] The soybean seed coat mainly contains dietary fiber and protein; the content of dietary fiber is 75% to 88%, insoluble dietary fiber accounts for 85% to 95% of the total dietary fiber; and the content of protein is 8% to 12%.
[0008] The mass volume ratio of the soybean hull powder and deionized water is 0.5:100 to 2:100 g / mL, preferably 1.5:100 to 2:100 g / mL, and most preferably 2:100 g / mL.
[0009] The oil phase is edible oil such as soybean oil, corn oil, rapeseed oil, etc.
[0010] The volume ratio of the oil phase to the soybean hull suspension is 5:95 to 45:55, preferably 25:75 to 35:65, and optimally 35:65.
[0011] Another object of the present invention is to provide a method for preparing an oil-in-water emulsion stabilized by using soybean seed hulls as a by-product, comprising the following steps:
[0012] Step (1), soybean husks are crushed and sieved to obtain soybean husk powder;
[0013] Step (2), dispersing the soybean husk powder into deionized water and performing high-pressure homogenization to prepare a soybean husk suspension;
[0014] Step (3): mixing the soybean seed coat suspension with the oil phase, and subjecting the mixture to high-speed shearing and high-pressure homogenization to obtain an oil-in-water emulsion.
[0015] In step (1), the soybean seed coat is crushed by a cyclone mill.
[0016] Considering that larger particles are likely to clog the high-pressure homogenizer during high-pressure homogenization, the soybean seed coats are crushed and then passed through a 200-mesh sieve.
[0017] In step (2), the homogenization pressure of the high-pressure homogenization treatment is 55 MPa to 65 MPa, preferably 60 MPa, and the number of cycles is 25 to 55 times, preferably 40 to 55 times.
[0018] In step (3), the high-speed shearing speed is 10,000 to 15,000 rpm, and the time is 1 to 3 minutes.
[0019] The homogenization pressure of the high-pressure homogenization is 40-50 MPa, and the cycle time is 3-5 minutes.
[0020] Beneficial effects of the present invention:
[0021] The present invention adopts soybean seed coat, a by-product of soybean oil production, and mechanically and physically modifies and micronizes it through high-pressure homogenization to obtain a soybean seed coat suspension. No chemical reagents are used in the preparation process, which is green and safe; and no waste gas or wastewater is generated, which is environmentally friendly and sustainable.
[0022] The present invention uses a soybean husk suspension and soybean oil to prepare an oil-in-water emulsion. The combined action of insoluble dietary fiber and protein enables the soybean husk suspension to form a stable oil-in-water emulsion. The stable oil-in-water emulsion of the soybean husk suspension exhibits no oil phase precipitation and no emulsion droplet aggregation after storage for at least one month, exhibiting excellent storage stability and suitable for use in the food industry. Furthermore, soybean husks are rich in dietary fiber and trace amounts of functional substances, which can enhance the nutritional value of food.
[0023] The present invention provides a potential value-added application for soybean seed coat. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 The microstructure of soybean seed coat prepared by different high-pressure homogenization cycles.
[0025] Figure 2 Particle size distribution of soybean seed coat suspensions prepared by different high-pressure homogenization cycles
[0026] Figure 3 Rheological properties of soybean seed coat suspensions prepared by different high-pressure homogenization cycles
[0027] Figure 4 Rheological properties of soybean seed hull suspensions prepared at different solid contents.
[0028] Figure 5 Macroscopic images of oil-in-water emulsions stabilized by soybean seed hull suspensions prepared at different solid contents.
[0029] Figure 6 Macroscopic images of stabilized oil-in-water emulsions of soybean seed coat suspensions prepared by different numbers of high-pressure homogenization cycles.
[0030] Figure 7 Macroscopic images of oil-in-water emulsions with different oil phase contents.
[0031] Figure 8 Optical microscopy images of oil-in-water emulsions stabilized by soybean seed coat suspensions prepared with different solid contents and stored for different times.
[0032] Figure 9 Optical microscopy images of oil-in-water emulsions stabilized by soybean seed coat suspensions prepared by different high-pressure homogenization cycles and stored for different times.
[0033] Figure 10 These are optical microscope images of oil-in-water emulsions with different oil phase contents stored for different times.
[0034] Figure 11This is a laser scanning confocal microscope image of an oil-in-water emulsion stabilized by a soybean seed coat suspension; the insoluble dietary fiber is stained with calcofluor white, appearing blue, and the oil phase is stained with Nile red, appearing red.
[0035] Figure 12 Laser scanning confocal microscopy image of an oil-in-water emulsion stabilized by a soybean seed coat suspension; the oil phase was stained with Nile red, and the protein was stained with Nile blue. DETAILED DESCRIPTION
[0036] The technical solution of the present invention is further described in detail below with reference to specific embodiments, but is not intended to limit the present invention.
[0037] The components and contents of the soybean seed coat used in the examples are shown in Table 1.
[0038] Table 1: Components and contents in soybean seed coat (mass fraction, %)
[0039]
[0040] Example 1
[0041] Effects of high-pressure homogenization cycles on the microstructure and rheological properties of soybean seed coat
[0042] Soybean husks were dried, pulverized using a cyclone mill, and passed through a 200-mesh sieve to obtain soybean husk powder. Five portions of soybean husk powder (1.5 g each) were weighed and dispersed into 100 mL of deionized water. The mixture was thoroughly mixed and homogenized using a high-pressure homogenizer at a pressure of 60 MPa for 10, 25, 40, and 55 cycles (denoted as HPH-10, HPH-25, HPH-40, and HPH-55, respectively) to prepare soybean husk suspensions of different morphologies.
[0043] The micromorphology of soybean seed coat suspension and soybean seed coat powder was observed by scanning electron microscopy. The soybean seed coat suspension with different treatments was diluted 100 times with deionized water, 10 μL was aspirated and deposited on the surface of mica sheet, dried naturally, and the surface was sprayed with gold to make it conductive, and observed by scanning electron microscopy. The results are shown in Figure 1 It can be seen that the soybean seed coat particles without homogenization treatment are mainly block-shaped and rod-shaped, with regular and uneven shapes; the soybean seed coat suspension prepared by 10 high-pressure homogenization cycles has larger particles, lower degree of fibrosis, and mostly flaky structures. The subsequent emulsion aqueous phase stratification is more serious; with the increase of the number of high-pressure homogenization cycles, the shape of the soybean seed coat after treatment changes from dense block to open fiber, and with the increase of the number of homogenization cycles, the degree of fibrosis increases and becomes entangled with each other.
[0044] The particle size distribution of homogenized soybean seed coat suspension and soybean seed coat powder was measured by laser particle size analyzer. Figure 2 It can be seen that after high-pressure homogenization, the average particle size of soybean seed coats decreases and the particle size distribution becomes wider. The smaller the particle size, the more stable the emulsion. This may be because the fiber morphology of soybean seed coat particles after high-pressure homogenization is uneven and easily entangled to form aggregates.
[0045] The suspension without high-pressure homogenization had particle sedimentation and the apparent viscosity could not be measured. Figure 3 The rheological properties of soybean seed coat suspensions show that after high-pressure homogenization treatment, the apparent viscosity of soybean seed coat suspensions with different forms increases with the increase in the number of high-pressure homogenization cycles.
[0046] Effects of different solid contents on the rheological properties of soybean seed coat suspensions
[0047] Soybean husks were dried, pulverized using a cyclone mill, and passed through a 200-mesh sieve to obtain soybean husk powder. Soybean husk powder (0.5, 1, 1.5, and 2 g, respectively) was dispersed in 100 mL of deionized water (corresponding to 0.5%, 1%, 1.5%, and 2% w / v, respectively). The mixture was thoroughly mixed and passed through a high-pressure homogenizer at 60 MPa for 40 cycles to prepare soybean husk suspensions with varying solid contents.
[0048] Figure 4 Figure 3 shows the rheological properties of soybean seed hull suspensions at different solid contents. It can be seen that after high-pressure homogenization, the apparent viscosity of the soybean seed hull suspension increases with the increase of solid content.
[0049] Example 2 Preparation of oil-in-water emulsion using soybean hull suspension
[0050] The soybean husk suspension prepared in Example 1 according to different solid contents (0.5, 1, 1.5, and 2 g of soybean husk powder were weighed and dispersed into 100 mL of deionized water, mixed thoroughly, and passed through a high-pressure homogenizer at a homogenization pressure of 60 MPa for 40 cycles) was mixed with soybean oil in a volume ratio of 85:15, and high-speed shearing was performed at a speed of 12000 rpm for 2 minutes, and then a high-pressure homogenizer was used to treat at 50 MPa for 5 minutes to obtain a water-in-oil emulsion stabilized by the soybean husk suspension. The effect of solid content on emulsion stability was explored. The results are shown in FIG. Figure 5The soybean husk suspensions obtained by high-pressure homogenization can stabilize oil-in-water emulsions, without oil phase precipitation, and with varying degrees of water phase sinking. The oil-in-water emulsions prepared from soybean husk suspensions with solid contents of 0.5 w / v, 1% w / v, 1.5% w / v, and 2% w / v have emulsification indices of 37.1%, 22.8%, 14.2%, and 10%, respectively. It can be seen that the oil-in-water emulsions prepared from soybean husk suspensions with solid contents of 1.5-2% w / v are relatively stable. In particular, the oil-in-water emulsion prepared using a soybean husk suspension with a solid content of 2% w / v as a stabilizer is the most stable, with the lower water layer having the lowest height, and no droplet aggregation is observed during storage.
[0051] The soybean husk suspension prepared in Example 1 according to the number of high-pressure homogenization cycles (1.5 g of soybean husk was dispersed in 100 mL of deionized water, thoroughly mixed, and homogenized using a high-pressure homogenizer at a homogenization pressure of 60 MPa for 10, 25, 40, and 55 cycles, respectively) was mixed with soybean oil in a volume ratio of 85:15, and high-speed shearing was performed at a speed of 12000 rpm for 2 minutes, and then a high-pressure homogenizer was used at 50 MPa for 5 minutes to obtain a stable oil-in-water emulsion of the soybean husk suspension. The results are shown in FIG. Figure 6 It can be seen that the soybean husk suspensions obtained through high-pressure homogenization can stabilize oil-in-water emulsions, with no oil phase precipitation and varying degrees of water phase sinking. The soybean husk suspensions obtained after 10, 25, 40, and 55 cycles stabilized the oil-in-water emulsions, with emulsification indices of 20%, 17.1%, 14.2%, and 14.2%, respectively. This indicates that the oil-in-water emulsions prepared using soybean husk suspensions obtained after 40 to 55 high-pressure homogenization cycles as stabilizers were relatively stable. A comprehensive analysis of emulsion stability and the low energy consumption required during the treatment process shows that the soybean husk suspension obtained after 40 high-pressure homogenization cycles was most effective in stabilizing the oil-in-water emulsion.
[0052] 1.5 g of soybean seed coat was dispersed in 100 mL of deionized water, mixed thoroughly, and homogenized with a high-pressure homogenizer at a homogenization pressure of 60 MPa for 40 cycles to obtain a soybean seed coat suspension; the soybean seed coat suspension and soybean oil were mixed in volume ratios of 95:5, 85:15, 75:25, 65:35, and 55:45 (i.e., oil phase content of 5 v%, 15 v%, 25 v%, 35 v%, and 45 v%), respectively, and sheared at a speed of 12000 rpm for 2 minutes, and then treated with a high-pressure homogenizer at 50 MPa for 5 minutes to obtain a stable oil-in-water emulsion of the soybean seed coat suspension. The results are shown in FIG. Figure 7It can be seen that different oil phase contents can form oil-in-water emulsions. The emulsification indices of the oil-in-water emulsions prepared at oil phase contents of 5%, 15%, 25%, 35%, and 45% are 14.6%, 14.2%, 9.7%, 7.8%, and 9.7%, respectively. Among them, the degree of emulsion stratification is the smallest when the oil phase content is 35% by volume.
[0053] Figure 8 、 Figure 9 、 Figure 10 Optical micrographs of the aforementioned oil-in-water emulsions stabilized with the soybean husk suspensions show that the oil-in-water emulsions stabilized with higher solids contents (1.5% w / v and 2% w / v) and higher degrees of fiberization (40 and 55 high-pressure homogenization cycles) exhibit smaller and more uniform droplets. When a soybean husk suspension with a solids content of 1.5% w / v was used as a stabilizer to prepare the oil-in-water emulsions, the droplet size increased from approximately 10 μm to 20-50 μm with increasing oil phase content, and uniformity decreased. When the oil phase content was between 25% and 35% by volume, creaming was minimized, and the droplets of the oil-in-water emulsions maintained good uniformity. Furthermore, all oil-in-water emulsions showed no significant change in droplet size after storage at 4°C for one month in a refrigerator, demonstrating that the oil-in-water emulsions stabilized with the soybean husk suspensions possessed excellent anti-agglomeration stability.
[0054] 1.5 g of soybean seed coat was dispersed in 100 mL of deionized water, mixed thoroughly, and homogenized using a high-pressure homogenizer at a homogenization pressure of 60 MPa for 40 cycles to obtain a soybean seed coat suspension; the soybean seed coat suspension and soybean oil were mixed in a volume ratio of 65:35, respectively, and high-speed sheared at a speed of 12000 rpm for 2 minutes, and then treated using a high-pressure homogenizer at 50 MPa for 5 minutes to obtain a stable oil-in-water emulsion of the soybean seed coat suspension. Figure 11 、 Figure 12 This is a laser scanning confocal microscope image of the water-in-oil emulsion. Figure 11 In the experiment, dietary fiber was stained with calcium fluorescent white, showing blue, and the oil phase was stained with Nile red, showing red; the results showed that soybean dietary fiber was mainly dispersed in the continuous phase, and the fiber network formed by mutual entanglement effectively hindered the coalescence of oil droplets. In order to further understand the mechanism of oil droplet stabilization, Figure 12 In this study, Nile red and Nile blue were used to stain the oil phase and proteins, respectively, resulting in green and red staining. The results indicate that proteins adhere to the surface of the oil droplets, forming an interfacial film. The proteins may be free proteins or protein-containing soybean seed coat cellulose polysaccharides. The combined effects of insoluble dietary fiber in the continuous phase and proteins in the interfacial film enable the soybean seed coat suspension treated with high-pressure homogenization to form a stable oil-in-water emulsion.
[0055] The above embodiments are provided to further illustrate the present invention, but should not be construed as limiting the scope of the present invention. Those skilled in the art will appreciate that equivalent modifications or substitutions may be made to some or all of the technical solutions. Therefore, various changes and modifications may be made without departing from the spirit and scope of the present invention, and the scope of protection shall be determined by the claims.
Claims
1. An oil-in-water emulsion stabilized by using soybean seed hull as a by-product, characterized by: The method uses soybean husks as raw materials, crushes and sieves them to obtain soybean husk powder, disperses the soybean husk powder in deionized water, and obtains soybean husk suspension by high-pressure homogenization. The soybean husk suspension is mixed with an oil phase, and a stable oil-in-water emulsion is obtained by high-speed shear dispersion and high-pressure homogenization. The soybean seed coat mainly contains dietary fiber and protein; the dietary fiber content is 75% to 88%, insoluble dietary fiber accounts for 85% to 95% of the total dietary fiber; the protein content is 8% to 12%; The mass volume ratio of the soybean hull powder and deionized water is 1.5:100 to 2:100 g / mL; when the soybean hull suspension is prepared by high-pressure homogenization, the homogenization pressure of the high-pressure homogenization is 55 MPa to 65 MPa, and the number of cycles is 25 to 55 times; The volume ratio of the oil phase to the soybean hull suspension is 25:75 to 45:
55.
2. The oil-in-water emulsion stabilized by soybean hulls according to claim 1, characterized in that: The volume ratio of the oil phase to the soybean hull suspension is 25:75 to 35:
65.
3. The oil-in-water emulsion stabilized by soybean hulls according to claim 2, characterized in that: The mass volume ratio of the soybean hull powder and deionized water is 2:100 g / mL; the volume ratio of the oil phase and the soybean hull suspension is 35:
65.
4. The oil-in-water emulsion stabilized by soybean hulls according to claim 1, characterized in that: The oil phase is soybean oil, corn oil or rapeseed oil.
5. A method for preparing an oil-in-water emulsion stabilized by using soybean husk as a by-product according to claim 1, characterized in that: The following steps are involved: Step (1), soybean husks are crushed and sieved to obtain soybean husk powder; Step (2), dispersing the soybean hull powder into deionized water and performing high-pressure homogenization to obtain a soybean hull suspension; the homogenization pressure of the high-pressure homogenization is 55 MPa to 65 MPa, and the number of cycles is 25 to 55 times; Step (3): mixing the soybean seed coat suspension with the oil phase, and subjecting the mixture to high-speed shearing and high-pressure homogenization to obtain an oil-in-water emulsion.
6. The method for preparing an oil-in-water emulsion stabilized by using soybean hulls as a by-product according to claim 5, characterized in that: In step (1), the soybean husks are crushed and then passed through a 200-mesh sieve.
7. The method for preparing an oil-in-water emulsion stabilized by using soybean husk as a by-product according to claim 5, characterized in that: In step (2), the number of cycles of the high-pressure homogenization treatment is 40 to 55 times.
8. The method for preparing an oil-in-water emulsion stabilized by using soybean husk as a by-product according to claim 5, characterized in that: In step (3), the high-speed shearing speed is 10,000 to 15,000 rpm, and the time is 1 to 3 minutes.
9. The method for preparing an oil-in-water emulsion stabilized by using soybean husk as a by-product according to claim 5, characterized in that: In step (3), the homogenization pressure of the high-pressure homogenization is 40-50 MPa, and the cycle time is 3-5 minutes.