Method for high efficiency embedding of lycopene by soybean lipophilin

Abstract

A method for efficiently encapsulating lycopene using soybean lipoprotein belongs to the field of food processing and functional ingredient encapsulation technology. The preparation method includes: extracting soybean lipoprotein from soybean raw materials; pretreating the obtained protein using ultrasound-assisted pH shifting technology; mixing the protein solution with anionic polysaccharides; preparing a complex through a thermally induced Maillard reaction; using the complex solution as the aqueous phase; and subjecting it to high-speed shearing and ultrasonic treatment with an oil phase containing dissolved lycopene to obtain a lycopene-loaded Pickering emulsion. This invention significantly improves the stability of Pickering emulsions by constructing modified protein-anionic polysaccharide composite emulsion particles, achieving efficient encapsulation and protection of lycopene, thus solving the problems of easy degradation, poor water solubility, and low bioavailability of lycopene.

Description

Technical Field

[0001] This invention belongs to the field of food processing and functional ingredient encapsulation technology, and relates to a method for preparing Pickering emulsion by modifying soybean lipophilic protein-polysaccharide Maillard complex using ultrasound-assisted pH shifting, and its application in the efficient encapsulation of lycopene. Background Technology

[0002] Lycopene is a fat-soluble carotenoid and a lipophilic isoprene compound. Due to its physiological functions such as immunomodulation, antioxidation (e.g., quenching singlet oxygen and scavenging superoxide free radicals), and prevention of various chronic diseases (e.g., cardiovascular diseases, eye diseases, and neurodegenerative diseases), it shows broad application prospects in functional foods, pharmaceuticals, and cosmetics. However, the presence of multiple unsaturated double bonds in its molecular structure makes it highly susceptible to oxidative degradation under light, oxygen, acidic conditions, or high temperatures. Furthermore, its extremely low water solubility not only hinders its effective dispersion and application in food matrices but also reduces its stability in the gastrointestinal tract after oral administration, leading to significant degradation and consequently affecting its bioavailability. To overcome these challenges, developing efficient delivery systems has become a key strategy for improving the solubility, stability, and ultimate bioavailability of lycopene.

[0003] Emulsions are effective carriers for encapsulating and delivering lipophilic bioactive substances. However, traditional emulsions are prone to Ostwald ripening, leading to droplet aggregation and phase separation, thus affecting their long-term stability. In contrast, Pickering emulsions stabilized by solid particles have attracted much attention in recent years due to their superior stability, controlled release characteristics, and enhanced protection of active ingredients. Among various emulsion stabilizers, proteins are widely used due to their natural origin and food-grade safety. Soy lipophilic protein, one of the main components of soy protein isolate (approximately 31%), contains oil-body-related proteins and phospholipids, giving it abundant hydrophobic domains and excellent oil-water interfacial activity, making it a potential candidate for encapsulating hydrophobic nutrients. However, the large number of hydrophobic domains also results in poor water solubility, which greatly limits its practical application. Furthermore, Pickering emulsions stabilized by single protein particles are still prone to instability near the isoelectric point pH or under high ionic strength conditions, thus limiting the efficiency of lycopene delivery. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a Pickering emulsion for efficient lycopene encapsulation and its preparation method. The method involves modifying and pretreating the protein to improve its solubility, and then further preparing a complex with anionic polysaccharides via a Maillard reaction. This constructs a high-performance Pickering emulsion that can efficiently load and protect lycopene, thus solving the problems of lycopene's easy oxidative degradation, poor water solubility, low bioavailability, and insufficient stability of existing single-protein emulsions.

[0005] The steps of this method are as follows: Step 1: After grinding and sieving soybeans, defatting with n-hexane to obtain defatted soybean meal. The defatted soybean meal was dry-heat treated at 70 ℃ for 2 h until the nitrogen solubility index reached 75%. The dry-heat treated defatted soybean meal was dissolved in deionized water, and the pH was adjusted to 8.0. After stirring at 25 ℃ for 1 h, it was centrifuged at 8000 rpm for 30 min. After centrifugation, the supernatant was taken and 10 mM Na2SO3 was added to adjust the pH to 5.8. It was centrifuged at 8000 rpm for 30 min to obtain the final supernatant. The pH of the final supernatant was adjusted to 5.0, and after heating, 50 mmol / L NaCl was added and the pH was adjusted to 5.5. It was then centrifuged at 8000 rpm for 30 min. The precipitate was taken and freeze-dried to obtain soybean lipophilic protein. Step 2: Dissolve the soybean lipoprotein obtained in Step 1 in deionized water and stir until the protein is completely dissolved. The concentration of the protein solution is 10 mg / ml. Perform pH shift treatment at pH 12.0 and then perform ultrasonic treatment using an ultrasonic device to adjust the pH of the ultrasonically treated solution back to 7.0 to obtain the pretreated soybean lipoprotein solution. Step 3: Mix the pretreated soybean lipophilic protein solution obtained in Step 2 with the anionic polysaccharide solution, heat at 80~90 ℃ for 1~3 h to carry out the Maillard reaction, and cool after the reaction is completed to obtain a protein-polysaccharide Maillard complex solution. The anionic polysaccharide is one of sodium alginate, gum arabic or xanthan gum. Step 4: The complex solution obtained in Step 3 is used as the aqueous phase and mixed with the oil phase containing lycopene at a volume ratio of 8~10:1. After high-speed shearing and ultrasonic treatment, a highly efficient lycopene-encapsulating Pickering emulsion is obtained.

[0006] The ultrasonic treatment described in steps two and four uses a power of 200-300 W and is performed in a pulse mode.

[0007] The optimal anionic polysaccharide selected in step three is sodium alginate, and the mass ratio of soybean lipophilic protein to anionic polysaccharide is 3~6:1.

[0008] The present invention discloses the following technical effects: 1. This invention effectively improves the solubility of soybean lipophilic proteins through ultrasound-assisted pH shifting technology, laying the foundation for the subsequent formation of stable Maillard complexes; 2. The protein-polysaccharide complex constructed by Maillard reaction in this invention, as the emulsifying particles of Pickering emulsion, significantly improves emulsification and stability. 3. This invention successfully solves the bottleneck problems of lycopene being easily degraded and oxidized, having poor water solubility and low bioavailability. The final Pickering emulsion has an encapsulation efficiency of up to 93.48% for lycopene and makes its bioaccessibility reach 78.93% after simulated gastrointestinal digestion. Attached Figure Description

[0009] Figure 1 The process flow diagram of this invention.

[0010] Figure 2 Comparison of solubility of soybean lipophilic protein after ultrasonic-assisted pH shifting treatment.

[0011] Figure 3 Comparison of emulsifying activity and stability of Pickering emulsions prepared from different polysaccharide-protein complexes.

[0012] Figure 4 Storage stability diagram of Pickering emulsions prepared from different polysaccharide-protein complexes.

[0013] Figure 5 Confocal laser microscope images of Pickering emulsions prepared from different polysaccharide-protein complexes.

[0014] Figure 6 Images of Pickering emulsions prepared from different polysaccharide-protein complexes.

[0015] Figure 7 Encapsulation efficiency of Pickering emulsion loaded with lycopene.

[0016] Figure 8 Average particle size versus zeta potential of lycopene-loaded Pickering emulsion after simulated gastrointestinal digestion.

[0017] Figure 9 Bioavailability diagram of lycopene in Pickering emulsion loaded with lycopene. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, this study combines the appendix... Figure 1The present invention will be further described in detail below. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0019] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0020] Example 1 Step 1: After grinding and sieving soybeans, defatting with n-hexane to obtain defatted soybean meal. The defatted soybean meal was dry-heat treated at 70 ℃ for 2 h until the nitrogen solubility index reached 75%. The dry-heat treated defatted soybean meal was dissolved in deionized water, and the pH was adjusted to 8.0. After stirring at 25 ℃ for 1 h, it was centrifuged at 8000 rpm for 30 min. After centrifugation, the supernatant was taken and 10 mM Na2SO3 was added to adjust the pH to 5.8. It was centrifuged at 8000 rpm for 30 min to obtain the final supernatant. The pH of the final supernatant was adjusted to 5.0, and after heating, 50 mmol / L NaCl was added and the pH was adjusted to 5.5. It was then centrifuged at 8000 rpm for 30 min. The precipitate was taken and freeze-dried to obtain soybean lipophilic protein. Step 2: Dissolve the soybean lipoprotein obtained in Step 1 in deionized water (10 mg / ml), stir until the protein is completely dissolved, adjust the pH to 12.0 using 1 M NaOH, and then perform ultrasonic treatment using an ultrasonic device (240 W, 20 min, pulse cycle of 4 s on and 2 s off). Finally, adjust the pH back to 7.0 to obtain the pretreated soybean lipoprotein solution. Step 3: Mix the soybean lipophilic protein solution obtained in Step 2 with sodium alginate (soybean lipophilic protein: sugar = 4:1, w / w), stir and heat the mixture in an 85°C water bath for 2 h, and cool after the reaction is complete to obtain a protein-polysaccharide Maillard complex solution. Step 4: The complex solution obtained in Step 3 is used as the aqueous phase and mixed with the oil phase at a volume ratio of 9:1. After high-speed shearing at 10,000 rpm for 2 min, it is ultrasonically treated with an ultrasonic device (240 W, 5 min, pulse period of 4 s on and 2 s off) to obtain Pickering emulsion. Step 5: The protein-sodium alginate complex solution is used as the aqueous phase and mixed with the oil phase containing lycopene at a volume ratio of 9:1. After high-speed shearing at 10,000 rpm for 2 min, ultrasonic treatment is performed using an ultrasonic device (240W, 5 min, pulse cycle of 4 s on and 2 s off) to obtain the Pickering emulsion containing lycopene.

[0021] Example 2 Step 1: After grinding and sieving soybeans, defatting with n-hexane to obtain defatted soybean meal. The defatted soybean meal was dry-heat treated at 70 ℃ for 2 h until the nitrogen solubility index reached 75%. The dry-heat treated defatted soybean meal was dissolved in deionized water, and the pH was adjusted to 8.0. After stirring at 25 ℃ for 1 h, it was centrifuged at 8000 rpm for 30 min. After centrifugation, the supernatant was taken and 10 mM Na2SO3 was added to adjust the pH to 5.8. It was centrifuged at 8000 rpm for 30 min to obtain the final supernatant. The pH of the final supernatant was adjusted to 5.0, and after heating, 50 mmol / L NaCl was added and the pH was adjusted to 5.5. It was then centrifuged at 8000 rpm for 30 min. The precipitate was taken and freeze-dried to obtain soybean lipophilic protein. Step 2: Dissolve the soybean lipoprotein obtained in Step 1 in deionized water (10 mg / ml), stir until the protein is completely dissolved, adjust the pH to 12.0 using 1 M NaOH, and then perform ultrasonic treatment using an ultrasonic device (240 W, 20 min, pulse cycle of 4 s on and 2 s off). Finally, adjust the pH back to 7.0 to obtain the pretreated soybean lipoprotein solution. Step 3: Mix the soybean lipophilic protein solution obtained in Step 2 with gum arabic (soybean lipophilic protein: sugar = 4:1, w / w), stir and heat the mixture in an 85°C water bath for 2 h, and cool after the reaction is complete to obtain a protein-polysaccharide Maillard complex solution. Step 4: The complex solution obtained in Step 3 is used as the aqueous phase and mixed with the oil phase at a volume ratio of 9:1. After high-speed shearing at 10,000 rpm for 2 min, it is ultrasonically treated with an ultrasonic device (240 W, 5 min, pulse period of 4 s on and 2 s off) to obtain Pickering emulsion. Step 5: The protein-sodium alginate complex solution is used as the aqueous phase and mixed with the oil phase containing lycopene at a volume ratio of 9:1. After high-speed shearing at 10,000 rpm for 2 min, ultrasonic treatment is performed using an ultrasonic device (240W, 5 min, pulse cycle of 4 s on and 2 s off) to obtain the Pickering emulsion containing lycopene.

[0022] Example 3 Step 1: After grinding and sieving soybeans, defatting with n-hexane to obtain defatted soybean meal. The defatted soybean meal was dry-heat treated at 70 ℃ for 2 h until the nitrogen solubility index reached 75%. The dry-heat treated defatted soybean meal was dissolved in deionized water, and the pH was adjusted to 8.0. After stirring at 25 ℃ for 1 h, it was centrifuged at 8000 rpm for 30 min. After centrifugation, the supernatant was taken and 10 mM Na2SO3 was added to adjust the pH to 5.8. It was centrifuged at 8000 rpm for 30 min to obtain the final supernatant. The pH of the final supernatant was adjusted to 5.0, and after heating, 50 mmol / L NaCl was added and the pH was adjusted to 5.5. It was then centrifuged at 8000 rpm for 30 min. The precipitate was taken and freeze-dried to obtain soybean lipophilic protein. Step 2: Dissolve the soybean lipoprotein obtained in Step 1 in deionized water (10 mg / ml), stir until the protein is completely dissolved, adjust the pH to 12.0 using 1 M NaOH, and then perform ultrasonic treatment using an ultrasonic device (240 W, 20 min, pulse cycle of 4 s on and 2 s off). Finally, adjust the pH back to 7.0 to obtain the pretreated soybean lipoprotein solution. Step 3: Mix the soybean lipophilic protein solution obtained in Step 2 with xanthan gum (soybean lipophilic protein: sugar = 4:1, w / w), stir and heat the mixture in an 85°C water bath for 2 h, and cool after the reaction is complete to obtain a protein-polysaccharide Maillard complex solution. Step 4: The complex solution obtained in Step 3 is used as the aqueous phase and mixed with the oil phase at a volume ratio of 9:1. After high-speed shearing at 10,000 rpm for 2 min, it is ultrasonically treated with an ultrasonic device (240 W, 5 min, pulse period of 4 s on and 2 s off) to obtain Pickering emulsion. Step 5: The protein-sodium alginate complex solution is used as the aqueous phase and mixed with the oil phase containing lycopene at a volume ratio of 9:1. After high-speed shearing at 10,000 rpm for 2 min, ultrasonic treatment is performed using an ultrasonic device (240W, 5 min, pulse cycle of 4 s on and 2 s off) to obtain the Pickering emulsion containing lycopene.

[0023] Example 4 Step 1: After grinding and sieving soybeans, defatting with n-hexane to obtain defatted soybean meal. The defatted soybean meal was dry-heat treated at 70 ℃ for 2 h until the nitrogen solubility index reached 75%. The dry-heat treated defatted soybean meal was dissolved in deionized water, and the pH was adjusted to 8.0. After stirring at 25 ℃ for 1 h, it was centrifuged at 8000 rpm for 30 min. After centrifugation, the supernatant was taken and 10 mM Na2SO3 was added to adjust the pH to 5.8. It was centrifuged at 8000 rpm for 30 min to obtain the final supernatant. The pH of the final supernatant was adjusted to 5.0, and after heating, 50 mmol / L NaCl was added and the pH was adjusted to 5.5. It was then centrifuged at 8000 rpm for 30 min. The precipitate was taken and freeze-dried to obtain soybean lipophilic protein. Step 2: Dissolve the soybean lipoprotein obtained in Step 1 in deionized water (10 mg / ml), stir until the protein is completely dissolved, adjust the pH to 12.0 using 1 M NaOH, and then perform ultrasonic treatment using an ultrasonic device (240 W, 20 min, pulse cycle of 4 s on and 2 s off). Finally, adjust the pH back to 7.0 to obtain the pretreated soybean lipoprotein solution. Step 3: The soybean lipophilic protein solution obtained in Step 2 is stirred and heated in a water bath at 85°C for 2 hours. After the reaction is completed, it is cooled to obtain a protein-polysaccharide Maillard complex solution. Step 4: The complex solution obtained in Step 3 is used as the aqueous phase and mixed with the oil phase at a volume ratio of 9:1. After high-speed shearing at 10,000 rpm for 2 min, it is ultrasonically treated with an ultrasonic device (240 W, 5 min, pulse period of 4 s on and 2 s off) to obtain Pickering emulsion. Step 5: The protein-sodium alginate complex solution is used as the aqueous phase and mixed with the oil phase containing lycopene at a volume ratio of 9:1. After high-speed shearing at 10,000 rpm for 2 min, ultrasonic treatment is performed using an ultrasonic device (240W, 5 min, pulse cycle of 4 s on and 2 s off) to obtain the Pickering emulsion containing lycopene.

[0024] Comparative example: Step 1: After grinding and sieving soybeans, defatting with n-hexane to obtain defatted soybean meal. The defatted soybean meal was dry-heat treated at 70 ℃ for 2 h until the nitrogen solubility index reached 75%. The dry-heat treated defatted soybean meal was dissolved in deionized water, and the pH was adjusted to 8.0. After stirring at 25 ℃ for 1 h, it was centrifuged at 8000 rpm for 30 min. After centrifugation, the supernatant was taken and 10 mM Na2SO3 was added to adjust the pH to 5.8. It was centrifuged at 8000 rpm for 30 min to obtain the final supernatant. The pH of the final supernatant was adjusted to 5.0, and after heating, 50 mmol / L NaCl was added and the pH was adjusted to 5.5. It was then centrifuged at 8000 rpm for 30 min. The precipitate was taken and freeze-dried to obtain soybean lipophilic protein. Step 2: Dissolve the soybean lipoprotein obtained in Step 1 in deionized water (10 mg / ml), stir until the protein is completely dissolved, adjust the pH to 12.0 using 1 M NaOH, and then perform ultrasonic treatment using an ultrasonic device (240 W, 20 min, pulse cycle of 4 s on and 2 s off). Finally, adjust the pH back to 7.0 to obtain the pretreated soybean lipoprotein solution. Step 3: The complex solution obtained in Step 2 is used as the aqueous phase and mixed with the oil phase at a volume ratio of 9:1. After high-speed shearing at 10,000 rpm for 2 min, it is ultrasonically treated with an ultrasonic device (240 W, 20 min, pulse period of 4 s on and 2 s off) to obtain Pickering emulsion. Step 4: The protein-sodium alginate complex solution is used as the aqueous phase and mixed with the oil phase containing lycopene at a volume ratio of 9:1. After high-speed shearing at 10,000 rpm for 2 min, ultrasonic treatment is performed using an ultrasonic device (240W, 5 min, pulse cycle of 4 s on and 2 s off) to obtain the Pickering emulsion containing lycopene.

[0025] Figure 2 The study investigated the change in solubility of soybean lipoprotein after ultrasound-assisted pH shift pretreatment. Compared with ultrasound or pH shift treatment alone, the combined ultrasound-assisted pH shift treatment resulted in the maximum solubility of soybean lipoprotein (92%). This significant improvement was mainly due to the synergistic effect of the two treatments: during pH shift, the structure of soybean lipoprotein unfolds, exposing internal polar groups and increasing its flexibility, thereby improving its interaction with water molecules; at the same time, the ultrasound cavitation effect generates a large number of cavitation bubbles, increasing the local temperature and pressure in the surrounding collapsed bubble region, which can further induce conformational changes in the protein and cause buried hydrophilic amino acid residues to be exposed on the molecular surface. These factors combined to promote the improvement in solubility.

[0026] Figure 3This study presents a comparison of the emulsifying activity and stability of Pickering emulsions prepared from different polysaccharide-protein complexes. Compared to soybean lipophilic protein treated with ultrasound-assisted pH shifting, the sample without added polysaccharides but subjected to heat treatment showed significantly reduced emulsifying activity and stability. Among the glycosylated complexes, the sample with added sodium alginate exhibited the best emulsifying activity. This is attributed to the introduction of more hydroxyl groups by sodium alginate, enhancing the hydrophilicity of the complex and thus increasing the effective concentration of protein in the aqueous phase and its interfacial diffusion capacity. In contrast, the emulsifying activity of the glycosylated complex with added xanthan gum was even lower than that of the pure protein sample. This is mainly due to the high solution viscosity caused by the unique molecular structure of xanthan gum, which restricts the diffusion of protein molecules to the oil-water interface, thereby reducing its emulsifying activity. The emulsifying stability of all glycosylated complexes was significantly improved compared to the control group. Among them, the sodium alginate sample showed excellent stability. In addition, the sample with added gum arabic showed better stability than xanthan gum. This may be because the highly branched structure of gum arabic creates a stronger steric hindrance effect on the oil droplet surface, effectively inhibiting droplet aggregation.

[0027] Figure 4 This study reflects the change in emulsion index of different samples stored at room temperature for 14 days. This index is a key parameter for assessing the long-term stability of emulsions on a macroscopic scale. The emulsion index of all emulsions stabilized by glycosylated complexes was significantly lower than that of the unglycosylated control group, indicating stronger resistance to phase separation and higher stability. This is mainly attributed to the enhanced macroscopic stability of the emulsion due to the covalent bonds formed between the protein and polysaccharide. The sample with added xanthan gum had the lowest emulsion index, exhibiting excellent anti-emulsion performance. The anti-emulsion ability of an emulsion is generally influenced by the density difference between the dispersed and continuous phases, droplet size, and the rheological properties of the system. The excellent performance of the xanthan gum-stabilized emulsion is due to the formation of a dense three-dimensional network structure within the continuous phase, which significantly increases the viscosity of the system, thereby effectively inhibiting droplet migration, flocculation, and aggregation. Compared with other samples with added polysaccharides, the sample with added gum arabic had the highest emulsion index. This may be due to the low negative charge density of gum arabic itself, resulting in weaker electrostatic repulsion, making droplets more prone to migration and aggregation, thus facilitating emulsion.

[0028] Figure 5Confocal laser microscopy images of stable Pickering emulsions from different samples are shown. Red fluorescence is used to label the oil phase, while green fluorescence labels the proteins. The images clearly show that red oil droplets are located inside the emulsion, and green-labeled proteins form an interfacial layer at the droplet boundaries, confirming the formation of a typical oil-in-water (O / W) emulsion system. The heated samples exhibit larger and more unevenly distributed droplets, which can be attributed to protein aggregation caused by heat treatment, leading to increased droplet size. After the addition of polysaccharides, the droplet distribution becomes more uniform, and the droplets transform from irregular shapes to smaller spherical shapes. In the glycosylated samples with added sodium alginate, the droplets are uniformly dispersed and significantly smaller than those in the systems with added xanthan gum and gum arabic. In the samples with added xanthan gum, slight aggregation and cross-linking of oil droplets and proteins are further observed, attributed to dissipative flocculation caused by xanthan gum, resulting in a gel-like network structure between the droplets.

[0029] Figure 6 Macroscopic images of the successfully constructed Pickering emulsions are shown. As shown, all emulsions exhibit a uniform milky white color with no visible layering or phase separation, indicating good physical stability. The Pickering emulsions prepared using sodium alginate demonstrate excellent emulsifying properties, making them suitable candidates for lycopene delivery systems in this study.

[0030] Figure 7 The encapsulation efficiency, average particle size, and zeta potential of the Pickering emulsion loaded with lycopene are presented. The emulsion stabilized by the sodium alginate-protein complex exhibits the best encapsulation performance, with an encapsulation efficiency of 93.49%, significantly better than the system using only pure protein. Simultaneously, the complex has a smaller average particle size and a higher absolute value of the zeta potential than the pure protein system, indicating that the introduction of sodium alginate enhances the electrostatic repulsion between droplets, effectively inhibiting droplet aggregation and thus improving the physical stability of the emulsion. This structural advantage facilitates a more uniform distribution of lycopene in the system, ultimately achieving higher encapsulation efficiency.

[0031] Figure 8The graph shows the changes in average particle size and zeta potential of Pickering emulsions loaded with lycopene after simulated gastrointestinal digestion. During the simulated gastric digestion stage, the average particle size of all emulsions significantly increased. This increase can be attributed to the low pH and high ionic strength environment of gastric juice weakening the electrostatic repulsion between droplets, thus promoting flocculation and aggregation. Simultaneously, the hydrolytic action of pepsin on interfacial proteins weakens their anti-agglomeration ability, further exacerbating droplet aggregation. Notably, the particle size of the sodium alginate complex emulsion was smaller than that of the single-protein Pickering emulsion. Upon entering the intestinal digestion stage, compared to the gastric digestion stage, the average particle size of all samples significantly decreased. This decrease was mainly due to the action of pancreatic lipase and protease, which further hydrolyzed lipid and protein components, leading to droplet breakage and enhanced dispersibility. Regarding zeta potential, the negative charge of all emulsions decreased during the gastric stage, which is related to the protonation of groups such as carboxyl groups under strong acid conditions. Once in the intestines, all post-digested emulsions exhibit a higher negative charge compared to the gastric stage. This charge is caused by concentrated negatively charged anionic substances (such as undigested protein aggregates and lipid droplets, micelles, or vesicles) on the surface of the digested material, as well as negatively charged substances (such as peptides or free fatty acids).

[0032] Figure 9 The diagram shows the bioavailability of lycopene in Pickering emulsions loaded with lycopene. After simulated digestion, the emulsion stabilized with a sodium alginate-protein complex exhibited the highest bioavailability, reaching 78.93%. During digestion, lycopene is released from the oil phase of the emulsion and subsequently encapsulated in a mixture of micelles formed by bile salts and lipid digestion products, thus being absorbed and utilized. The presence of polysaccharides in the emulsion forms a thick protein-polysaccharide interfacial layer at the oil-water interface, helping to protect lycopene from degradation in the gastrointestinal environment.

Claims

1. A method for efficiently encapsulating lycopene using soybean lipophilic protein, characterized in that, The steps of this method are as follows: Step 1: After grinding and sieving soybeans, defatting with n-hexane to obtain defatted soybean meal. The defatted soybean meal was dry-heat treated at 70 ℃ for 2 h until the nitrogen solubility index reached 75%. The dry-heat treated defatted soybean meal was dissolved in deionized water, and the pH was adjusted to 8.

0. After stirring at 25 ℃ for 1 h, it was centrifuged at 8000 rpm for 30 min. After centrifugation, the supernatant was taken and 10 mM Na2SO3 was added to adjust the pH to 5.

8. It was centrifuged at 8000 rpm for 30 min to obtain the final supernatant. The pH of the final supernatant was adjusted to 5.0, and after heating, 50 mmol / L NaCl was added and the pH was adjusted to 5.

5. It was then centrifuged at 8000 rpm for 30 min. The precipitate was taken and freeze-dried to obtain soybean lipophilic protein. Step 2: Dissolve the soybean lipoprotein obtained in Step 1 in deionized water and stir until the protein is completely dissolved. The concentration of the protein solution is 10 mg / ml. Perform pH shift treatment at pH 12.0 and then perform ultrasonic treatment using an ultrasonic device to adjust the pH of the ultrasonically treated solution back to 7.0 to obtain the pretreated soybean lipoprotein solution. Step 3: Mix the pretreated soybean lipophilic protein solution obtained in Step 2 with the anionic polysaccharide solution, heat at 80~90 ℃ for 1~3 h to carry out the Maillard reaction, and cool after the reaction is completed to obtain a protein-polysaccharide Maillard complex solution. The anionic polysaccharide is one of sodium alginate, gum arabic or xanthan gum. Step 4: The complex solution obtained in Step 3 is used as the aqueous phase and mixed with the oil phase containing lycopene at a volume ratio of 8~10:

1. After high-speed shearing and ultrasonic treatment, a highly efficient lycopene-encapsulating Pickering emulsion is obtained.

2. The method for efficiently encapsulating lycopene using soybean lipophilic protein according to claim 1, characterized in that, The ultrasonic treatment described in steps two and four uses a power of 200-300 W and is performed in a pulse mode.

3. The method for efficiently encapsulating lycopene using soybean lipophilic protein according to claim 1, characterized in that, The optimal anionic polysaccharide selected in step three is sodium alginate, and the mass ratio of soybean lipophilic protein to anionic polysaccharide is 3~6:1.

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