Preparation method and application of soybean protein isolate-tannic acid-hydrophobic liquid compound

Abstract

The invention discloses a preparation method and application of a soybean protein isolate-tannic acid hydrophobic liquid compound, and belongs to the technical field of protein-based carrier construction.A carrier is constructed only through soybean protein and tannic acid in an acid environment, and the carrier can be used for loading the hydrophobic liquid compound in the field of perfume and essence; the loaded hydrophobic liquid compound and tannic acid can be released in a water-based system at the same time, the degradation rate of the hydrophobic liquid compound in the water-based system is slowed down in a physical barrier and free radical scavenging synergistic mode in the system, and the loss of spices and essences in the preparation process is reduced to a great extent.

Description

Technical Field

[0001] The invention belongs to the technical field of protein-based carrier construction, and in particular relates to a preparation method of a soy protein isolate-tannic acid@hydrophobic liquid compound and an application thereof. Background Art

[0002] The reaction of proteins with tannic acid has been discussed for a long time. Tannic acid can be used to precipitate proteins in the food industry. Recently, complexes of proteins with tannic acid have been prepared in covalent or non-covalent forms, and they show strong antioxidant properties due to the special molecular structure of tannic acid. However, there are few reports on the formation of stable complexes of soy protein isolate-tannic acid complexes at pH 3.0.

[0003] In recent years, the development of microcapsules based on carrier technology in the field of flavors and fragrances has made great progress. However, most studies focus on the preparation of capsules loaded with flavors and fragrances based on polymer materials. For example, CN107159069A, CN106179142A and CN107083457A prepared microcapsules loaded with flavors through polyurethane technology, and these microcapsules are difficult to be applied in the food field. The paper Preparation of pickeringemulsions based on soy protein isolate-tannic acid for protecting aromacompounds and their application in beverages published by the research group of Shanghai University of Applied Technology in Food Chemistry constructed a Pickering emulsion loaded with aromatic substances based on soy protein isolate and tannic acid and applied it to the beverage field, showing good oxidative stability. However, the emulsion needs to be used in a water-based system, which limits its scope of application. Therefore, it is necessary and urgent to develop a nano-micro carrier that uses common raw materials in the food industry, has a simple and convenient preparation method, and has a pollution-free preparation process, and apply it to the embedding and delivery of flavors and fragrances. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a preparation method and application of soybean protein isolate-tannic acid@hydrophobic liquid compound.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention:

[0007] A method for preparing a soy protein isolate-tannic acid@hydrophobic liquid compound comprises the following steps:

[0008] 1) dispersing soy protein isolate in water and stirring to obtain a soy protein isolate dispersion;

[0009] 2) adjusting the pH of the soy protein isolate dispersion to acidic by using an acidity regulator, and stirring uniformly to obtain an acidified soy protein isolate dispersion;

[0010] 3) dispersing tannic acid in water, and adjusting the pH to acidic with an acidity regulator to obtain a tannic acid aqueous solution;

[0011] 4) pre-dispersing the acidified soy protein isolate dispersion with a hydrophobic liquid compound to be loaded to obtain an emulsion;

[0012] 5) mixing the emulsion of step 4) with the tannic acid aqueous solution of step 3), and ultrasonicating in an ice-water bath to obtain a soy protein isolate-tannic acid@hydrophobic liquid compound dispersion;

[0013] 6) washing, centrifuging, resuspending and freeze-drying the soy protein isolate-tannic acid@hydrophobic liquid compound dispersion to obtain the soy protein isolate-tannic acid@hydrophobic liquid compound.

[0014] Preferably, in step 1), after dispersing the soy protein isolate in water, the stirring time is not less than 2 hours to ensure that the soy protein isolate is evenly dispersed in the water.

[0015] Preferably, the concentration of the soy protein isolate dispersion is 30-60 mg / mL, more preferably 30-45 mg / mL.

[0016] Preferably, in step 2) and step 3), the acidity regulator is one of hydrochloric acid, citric acid, malic acid, tartaric acid and citric acid-sodium citrate solution.

[0017] Preferably, in step 2), the pH is adjusted to 2.0-4.3. The isoelectric point of soy protein isolate is about pH=4.3. When the acidity is lower than 2.0-4.3, the protein is positively charged and produces a suspension.

[0018] Preferably, in step 2), the stirring time is not less than 2 hours.

[0019] Preferably, in step 3), the pH is adjusted to 2.0-4.6. This pH can be adjusted to match the pH of the acidified soy protein isolate dispersion.

[0020] Preferably, in step 3), the concentration of the tannic acid aqueous solution is 0.001-100 mg / mL.

[0021] Preferably, in step 4), the pre-dispersion process includes: one or more combinations of standing, stirring, high-speed dispersion, ultrasound or homogenization, which are adjusted according to the characteristics of the hydrophobic liquid compound to be loaded. The pre-dispersion process is carried out at 0-5°C or room temperature (25±2°C) according to the characteristics of the hydrophobic liquid compound to be loaded.

[0022] Preferably, in step 4), the hydrophobic liquid compound may be a small molecule volatile compound monomer or mixture involved in the field of spices and flavors, may be a volatile compound obtained from natural plants by an extraction method, or may be a mixture of the above monomer or mixture and a solvent. It should be noted that the hydrophobic liquid compound involved in the field of spices and flavors may have a liquid state that is changed according to the temperature. Therefore, the state corresponding to the temperature is not specified in the present invention, that is, the hydrophobic compounds involved in the field of spices and flavors that present liquid at a reasonable temperature can all be used as the object to be loaded. The hydrophobic liquid compound includes terpenes, terpenoids, butyl lactones, lemon essential oil, rose essence or edible sweet orange essence, more preferably including limonene, camphene, linalool, geraniol, benzyl acetate, neryl acetate, eugenol, vanillin, ethyl maltol, menthol, lemon essential oil, rose extract, milk essence, coffee essence, black tea peanut essence or roast beef essence.

[0023] Preferably, the solvent comprises one or more mixtures of ethanol, propylene glycol, dipropylene glycol, butylene glycol, pentylene glycol, medium chain fatty acid glycerides and citric acid glycerides.

[0024] Preferably, the mixing ratio of the solvent and the hydrophobic liquid compound involved in the field of flavors and fragrances can be any ratio.

[0025] Preferably, in step 5), the volume ratio of the emulsion in step 4) to the tannic acid aqueous solution in step 3) is 1:(1-5), that is, the mass ratio of soy protein isolate to tannic acid in the system is 1:(0.00002-33.33).

[0026] In step 5), ultrasound in an ice-water bath can promote uniform dispersion of the system.

[0027] Preferably, in step 6), the drying method is not limited as long as the drying effect can be achieved. The drying method includes room temperature drying, forced air drying, freeze drying or vacuum freeze drying.

[0028] At present, only reports have found that under pH 3.0, the absolute value of the ζ-potential of the formed complex is high and > 0. Protein can form soluble-insoluble complexes with tannic acid under acidic conditions. These complexes are formed by hydrogen bonds, and phenolic hydroxyl groups exist as hydrogen bond donors in the system. Based on this, the present invention proposes a method for preparing soy protein isolate-tannic acid @ hydrophobic liquid compound and applies it to the field of flavors and fragrances, in order to obtain a possibility of preparing a flavor and fragrance carrier using only soy protein isolate and tannic acid in a green and sustainable process.

[0029] The second technical solution of the present invention:

[0030] The present invention also provides a soy protein isolate-tannic acid@hydrophobic liquid compound prepared according to the method.

[0031] The third technical solution of the present invention:

[0032] The present invention also provides application of the soybean protein isolate-tannic acid@hydrophobic liquid compound in the field of spices and flavors.

[0033] The soy protein isolate-tannic acid@hydrophobic liquid compound of the present invention has a very strong performance of inhibiting the growth of microorganisms when the hydrophobic liquid compound is not loaded, and has a good inhibitory effect on common spoilage microorganisms in food.

[0034] The soy protein isolate-tannic acid@hydrophobic liquid compound of the present invention has a coral-like microstructure, a micron-level scale, and a narrow particle size distribution.

[0035] Preferably, when the hydrophobic liquid compound is a terpene compound, a soy protein isolate-tannic acid carrier loaded with terpene compounds is prepared, and no visible agglomeration phenomenon occurs during a 30-day stability study, and the loss rate of caryophyllene is much lower than that of the β-cyclodextrin group used as a control.

[0036] Preferably, when the hydrophobic liquid compound is a terpene alcohol compound, the prepared soy protein isolate-tannic acid carrier loaded with the terpene alcohol compound has no visible agglomeration phenomenon in the 30-day stability test.

[0037] Preferably, when the hydrophobic liquid compound is a butyl lactone compound, the prepared soy protein isolate-tannic acid carrier loaded with the butyl lactone compound has no visible agglomeration phenomenon in the 30-day stability test.

[0038] Preferably, when the hydrophobic liquid compound is lemon essential oil, the prepared soy protein isolate-tannic acid carrier loaded with lemon essential oil has no visible agglomeration phenomenon in the 30-day stability test.

[0039] Preferably, when the hydrophobic liquid compound is rose essence, the prepared product is a soy protein isolate-tannic acid carrier loaded with rose essence, and no agglomeration phenomenon visible to the naked eye occurs during a 30-day stability test.

[0040] Preferably, when the hydrophobic liquid compound is edible sweet orange flavor, the prepared product is a soy protein isolate-tannic acid carrier loaded with edible sweet orange flavor, which is mixed with a sweetener, an acidity regulator and dextrin, and then dispersed in water. The system is uniform and stable, and the aroma conforms to the characteristic aroma of sweet orange, and no visible precipitation appears within 30 minutes.

[0041] Compared with the prior art, the present invention has the following advantages and technical effects:

[0042] 1. Currently known studies on the interaction between soy protein isolate and polyphenols mainly focus on the interaction under neutral or alkaline environments. The research on soy protein isolate and polyphenols under acidic environments is at a blank stage at home and abroad. The present invention discloses a composite with carrier function constructed by using protein and polyphenols under acidic environments, which can be used in the field of spices and flavors.

[0043] 2. Currently known processes for loading hydrophobic liquid compounds based on protein are mainly focused on compounding proteins with polysaccharides, and using complex coacervation to encapsulate hydrophobic liquid compounds by adjusting surface charge, thereby achieving the purpose of loading. However, such methods are complicated to operate, and the preparation process involves risky substances that are difficult to completely remove. The present invention discloses a carrier constructed using only soybean protein and tannic acid in an acidic environment, which has good application prospects in the field of flavors and fragrances.

[0044] 3. Currently, the only known technology for loading hydrophobic liquid compounds on a protein base is mainly achieved by spray drying. However, the field of flavors and fragrances mostly involves terpenes and their oxygen-containing derivatives, which are volatile and easy to oxidize and deteriorate. The soy protein isolate-tannic acid carrier disclosed in the present invention can be prepared at room temperature or low temperature, which greatly reduces the loss of flavors and fragrances during the preparation process.

[0045] 4. The soy protein isolate-tannic acid@hydrophobic liquid compound disclosed in the present invention can simultaneously release the loaded hydrophobic liquid compound and tannic acid in a water-based system, and slow down the degradation rate of the hydrophobic liquid compound in the water-based system in a synergistic manner of physical barrier and free radical scavenging in the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0047] Figure 1 It is a schematic diagram of the simulated structure of 11S soy protein isolate;

[0048] Figure 2 It is a schematic diagram of the simulated structure of 7S soy protein isolate;

[0049] Figure 3 This is a scanning electron microscope image of the soy protein isolate-tannic acid@limonene carrier material with a tannic acid concentration of 30 mg / mL in Example 1 at a size of 5 μm;

[0050] Figure 4 This is a scanning electron microscope image of the soy protein isolate-tannic acid@limonene carrier material with a tannic acid concentration of 30 mg / mL in Example 1 at a size of 1 μm. DETAILED DESCRIPTION

[0051] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0052] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0053] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0054] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0055] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0056] Unless otherwise specified, the room temperature in the present invention is 25±2°C.

[0057] All raw materials used in the embodiments of the present invention are purchased from the market. For example, soy protein was purchased from Shanghai Myrrel Biochemical Technology Co., Ltd.; tannic acid was purchased from Shanghai Myrrel Biochemical Technology Co., Ltd.; gallic acid was purchased from Shanghai Titan Technology Co., Ltd.; epigallocatechin gallate was purchased from Shanghai Myrrel Biochemical Technology Co., Ltd.; and tea polyphenols (purity ≥ 95%) were purchased from Shanghai Myrrel Biochemical Technology Co., Ltd.

[0058] In the present invention, the preparation method of the homemade alkali-soluble acid-precipitated purified soy protein isolate (whose main components are mixed soy protein isolate of 11S and 7S) is as follows: 3g of soy protein is dispersed in 100mL of deionized water, stirred until fully dispersed, and a soy protein dispersion is obtained. The pH of the soy protein dispersion is adjusted to 8.0 using a 1M sodium hydroxide solution, stirred continuously at room temperature, and centrifuged at a speed of 10000×g for 15min to obtain a supernatant (mixed soy protein isolate dispersion of 7s and 11s). Purification: Use 1M hydrochloric acid to adjust the pH of the supernatant to 4.5, stir for 2 hours, store at 4°C overnight, centrifuge at 6000×g for 15 minutes, wash with deionized water three times and disperse in deionized water; adjust the pH to 7.0 with 1M sodium hydroxide solution or 1M hydrochloric acid, dialyze with a 3500Da dialysis bag for at least 24 hours, replace the deionized water every 6 hours, and try to maintain weak microbial conditions during the experiment (this experiment was carried out in a clean bench). The soy protein isolate dispersion obtained by dialysis was freeze-dried to obtain the homemade alkali-soluble acid-precipitated purified soy protein isolate (the main component is a mixed soy protein isolate of 11S and 7S), which was placed in a dark and dry place for subsequent use.

[0059] The simulated structure diagram of 11S soy protein isolate is shown in Figure 1 , the simulated structure diagram of 7S soybean protein isolate is shown in Figure 2 .

[0060] The technical solution of the present invention is further illustrated by the following embodiments.

[0061] Example 1

[0062] A method for preparing a limonene-loaded soy protein isolate-tannic acid carrier dispersion:

[0063] 1) Dispersing the homemade soy protein isolate purified by alkali dissolution and acid precipitation in deionized water at 30 mg / mL, stirring at room temperature for 2 h, and refrigerating at 4° C. overnight to obtain a soy protein isolate dispersion;

[0064] 2) using 1 M hydrochloric acid to accurately adjust the pH of the soy protein isolate dispersion to 3.0, stirring at room temperature for 4 hours, and refrigerating at 4° C. overnight to obtain an acidified soy protein isolate dispersion;

[0065] 3) dispersing tannic acid in deionized water at a concentration of 30 mg / mL, using an ultrasonic water bath at 25° C. to assist dispersion, obtaining a tannic acid solution, and using 1 M hydrochloric acid to accurately adjust the pH of the tannic acid solution to 3.0 to obtain a tannic acid aqueous solution, which was stored away from light;

[0066] 4) mixing the acidified soy protein isolate dispersion in step 2) with limonene at a volume ratio of 95:5, high-speed shearing at 6000 rpm for 3 min, and then stirring at 300 rpm for 2 h to obtain a limonene emulsion stabilized by the acidified soy protein isolate dispersion;

[0067] 5) The limonene emulsion stabilized by the soy protein isolate dispersion acidified in step 4) is mixed with the tannic acid aqueous solution in step 3) in a volume ratio of 1:1, and the mixing process is carried out in an ultrasonic water bath equipped with an ice bag for 30 minutes to obtain a limonene-loaded soy protein isolate-tannic acid carrier dispersion, which is recorded as soy protein isolate-tannic acid@limonene.

[0068] Comparative Example 1

[0069] A method for preparing a limonene-loaded soy protein isolate-gallic acid carrier dispersion:

[0070] 1) Dispersing the homemade soy protein isolate purified by alkali dissolution and acid precipitation in deionized water at 30 mg / mL, stirring at room temperature for 2 h, and refrigerating at 4° C. overnight to obtain a soy protein isolate dispersion;

[0071] 2) using 1 M hydrochloric acid to accurately adjust the pH of the soy protein isolate dispersion to 3.0, stirring at room temperature for 4 hours, and refrigerating at 4° C. overnight to obtain an acidified soy protein isolate dispersion;

[0072] 3) dispersing gallic acid in deionized water at a concentration of 30 mg / mL to obtain a gallic acid solution, and accurately adjusting the pH of the gallic acid solution to 3.0 using 1 M hydrochloric acid to obtain a gallic acid aqueous solution, which was stored in the dark;

[0073] 4) mixing the acidified soy protein isolate dispersion in step 2) with limonene at a volume ratio of 95:5, high-speed shearing at 6000 rpm for 3 min, and then stirring at 300 rpm for 2 h to obtain a limonene emulsion stabilized by the acidified soy protein isolate dispersion;

[0074] 5) The limonene emulsion stabilized by the acidified soy protein isolate dispersion in step 4) is mixed with the gallic acid aqueous solution in step 3) in a volume ratio of 1:1, and the mixing process is carried out in an ultrasonic water bath equipped with an ice bag for 30 minutes to obtain a limonene-loaded soy protein isolate-gallic acid carrier dispersion, which is recorded as soy protein isolate-gallic acid@limonene.

[0075] Comparative Example 2

[0076] A method for preparing a limonene-loaded soy protein isolate-epigallocatechin gallate carrier dispersion:

[0077] 1) Dispersing the homemade soy protein isolate purified by alkali dissolution and acid precipitation in deionized water at 30 mg / mL, stirring at room temperature for 2 h, and refrigerating at 4° C. overnight to obtain a soy protein isolate dispersion;

[0078] 2) using 1 M hydrochloric acid to accurately adjust the pH of the soy protein isolate dispersion to 3.0, stirring at room temperature for 4 hours, and refrigerating at 4° C. overnight to obtain an acidified soy protein isolate dispersion;

[0079] 3) dispersing epigallocatechin gallate in deionized water at a concentration of 10 mg / mL, assisting dispersion by ultrasonic water bath at 25° C., and accurately adjusting the pH of the epigallocatechin gallate solution to 3.0 using 1 M hydrochloric acid to obtain an epigallocatechin gallate aqueous solution, which was stored in the dark;

[0080] 4) mixing the acidified soy protein isolate dispersion in step 2) with limonene at a volume ratio of 95:5, high-speed shearing at 6000 rpm for 3 min, and then stirring at 300 rpm for 2 h to obtain a limonene emulsion stabilized by the acidified soy protein isolate dispersion;

[0081] 5) The limonene emulsion stabilized by the soy protein isolate dispersion acidified in step 4) is mixed with the epigallocatechin gallate aqueous solution in step 3) in a volume ratio of 1:1, and the mixing process is carried out in an ultrasonic water bath equipped with an ice bag for 30 minutes to obtain a soy protein isolate-epigallocatechin gallate carrier dispersion loaded with limonene, which is recorded as soy protein isolate-epigallocatechin gallate@limonene.

[0082] Comparative Example 3

[0083] A method for preparing a limonene-loaded soy protein isolate-tea polyphenols carrier dispersion:

[0084] 1) Dispersing the homemade soy protein isolate purified by alkali dissolution and acid precipitation in deionized water at 30 mg / mL, stirring at room temperature for 2 h, and refrigerating at 4° C. overnight to obtain a soy protein isolate dispersion;

[0085] 2) using 1 M hydrochloric acid to accurately adjust the pH of the soy protein isolate dispersion to 3.0, stirring at room temperature for 4 hours, and refrigerating at 4° C. overnight to obtain an acidified soy protein isolate dispersion;

[0086] 3) Dispersing tea polyphenols (purity ≥ 95%) in deionized water at a concentration of 20 mg / mL, using an ultrasonic water bath to assist dispersion at 25° C. Using 1 M hydrochloric acid to accurately adjust the pH of the tea polyphenol solution to 3.0, a tea polyphenol aqueous solution was obtained, and stored in the dark;

[0087] 4) mixing the acidified soy protein isolate dispersion in step 2) with limonene at a volume ratio of 95:5, high-speed shearing at 6000 rpm for 3 min, and then stirring at 300 rpm for 2 h to obtain a limonene emulsion stabilized by the acidified soy protein isolate dispersion;

[0088] 5) The limonene emulsion stabilized by the acidified soy protein isolate dispersion in step 4) is mixed with the tea polyphenol aqueous solution in step 3) in a volume ratio of 1:1, and the mixing process is carried out in an ultrasonic water bath equipped with an ice bag for 30 minutes to obtain a limonene-loaded soy protein isolate-tea polyphenol carrier dispersion, recorded as soy protein isolate-tea polyphenol@limonene.

[0089] Experimental Example 1

[0090] This experimental example aims to compare the formation process of soy protein isolate-tannic acid @ limonene, soy protein isolate-gallic acid @ limonene, soy protein isolate-epigallocatechin gallate @ limonene and soy protein isolate-tea polyphenols @ limonene obtained in Example 1 and Comparative Examples 1-3.

[0091] The limonene-loaded carrier dispersions obtained in Example 1 and Comparative Examples 1-3 were centrifuged at 10,000×g for 15 min in a refrigerated centrifuge, and the volumes / masses of the upper cream layer, the middle layer, and the lower layer of sediment were compared. The state of the limonene-loaded carrier after centrifugation is shown in Table 1, and the sensory analysis of the lower layer of sediment is shown in Table 2.

[0092] Table 1 State of the carrier loaded with limonene after centrifugation in Example 1 and Comparative Examples 1-3

[0093]

[0094] According to the data in Table 1, in Example 1, where only tannic acid was added, almost no cream layer was visible on the upper layer, a light yellow clear liquid appeared in the middle layer, and a large amount of precipitation appeared in the lower layer. This means that tannic acid completely precipitated the acidified soy protein isolate emulsion loaded with limonene in the system. In contrast, in Comparative Examples 1-3, there was almost no precipitation or only a small amount of precipitation in soy protein isolate-gallic acid@limonene, soy protein isolate-epigallocatechin gallate@limonene, and soy protein isolate-tea polyphenols@limonene, indicating that the emulsion in the system was not completely precipitated.

[0095] Table 2 Sensory analysis of lower sediment of Example 1 and Comparative Examples 1-3

[0096]

[0097] According to the data in Table 2, only the lower precipitate obtained in Example 1 exhibits a strong citrus-like aroma and has the characteristic aroma of limonene. However, the soy protein isolate-gallic acid@limonene, soy protein isolate-epigallocatechin gallate@limonene and soy protein isolate-tea polyphenols@limonene in Comparative Examples 1-3 have almost no aroma or only a very light characteristic odor of limonene.

[0098] In summary, only the tannic acid in Example 1 has the ability to load the acidified soy protein isolate emulsion of limonene in the precipitation system, while the gallic acid, epigallocatechin gallate or tea polyphenols in Comparative Examples 1-3 have almost no or weaker ability to load the acidified soy protein isolate emulsion of limonene in the precipitation system. The reason may be that the special molecular structure of tannic acid and the characteristics of polyphenol hydroxyl groups play a crucial role in the process of participating in the assembly of soy protein isolate. Therefore, it can be considered that tannic acid has an irreplaceable important role in a variety of water-soluble phenolic acids. During the experiment, it was found that the water solubility of epigallocatechin gallate is weaker than that of gallic acid and tannic acid, and it is difficult to disperse in aqueous solution under high concentration conditions. The preparation requirements and difficulty of the carrier are increased by the ultrasonic cell disruptor, which affects the preparation of the carrier. During the experiment, it was also found that the comparative examples 2 and 3 with added epigallocatechin gallate and tea polyphenols were turbid emulsions in the middle layer after centrifugation. This may be because the addition of epigallocatechin gallate and tea polyphenols enhances the stability of the system, but this creates difficulties in the preparation of the carrier.

[0099] Experimental Example 2

[0100] The purpose of this experimental example is to compare the changes of soy protein isolate-tannic acid @ limonene, soy protein isolate-gallic acid @ limonene, soy protein isolate-epigallocatechin gallate @ limonene and soy protein isolate-tea polyphenols @ limonene obtained in Example 1 and Comparative Examples 1-3 during the freeze-drying process.

[0101] The limonene-loaded carrier dispersions obtained in Example 1 and Comparative Examples 1-3 were centrifuged, washed with deionized water, resuspended three times, and then freeze-dried. The aroma intensity of the four carriers was preliminarily evaluated. The sensory evaluation results are shown in Table 3.

[0102] Table 3 Sensory evaluation of Example 1 and Comparative Examples 1-3 after freeze drying

[0103] Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Odor intensity +++ - - +

[0104] Note: In Table 3, “-” indicates that the odor is almost inaudible, “+” indicates that there is a faint odor, “++” indicates that a citrus-like characteristic odor can be smelled, and “+++” indicates that a strong citrus-like characteristic odor can be strongly felt.

[0105] According to the results in Table 3, only the soy protein isolate-tannic acid @ limonene with tannic acid added still retains a strong characteristic citrus smell after freeze-drying, while the soy protein isolate-gallic acid @ limonene and soy protein isolate-epigallocatechin gallate @ limonene obtained in Comparative Examples 1 and 2 have almost no smell, and the soy protein isolate-tea polyphenols @ limonene obtained in Comparative Example 3 can only perceive a weak smell. This is the same as the result obtained in Experimental Example 1, and tannic acid has a significant effect on the formation of soy protein isolate-polyphenols @ hydrophobic liquid compounds.

[0106] Example 2

[0107] A method for preparing a limonene-loaded soy protein isolate-tannic acid carrier (soy protein isolate-tannic acid@limonene carrier):

[0108] 1) Dispersing the homemade soy protein isolate purified by alkali dissolution and acid precipitation in deionized water at 30 mg / mL, stirring at room temperature for 2 h, and refrigerating at 4° C. overnight to obtain a soy protein isolate dispersion;

[0109] 2) using 1 M hydrochloric acid to accurately adjust the pH of the soy protein isolate dispersion to 3.0, stirring at room temperature for 4 hours, and refrigerating at 4° C. overnight to obtain an acidified soy protein isolate dispersion;

[0110] 3) tannic acid was dispersed in deionized water at a concentration of 30 mg / mL, and an ultrasonic water bath was used to assist dispersion at 25° C. to obtain a tannic acid solution, and 1 M hydrochloric acid was used to accurately adjust the pH of the tannic acid solution to 3.0 to obtain a tannic acid aqueous solution (i.e., the concentration of the tannic acid aqueous solution in this embodiment is 30 mg / mL), which was stored away from light;

[0111] 4) mixing the acidified soy protein isolate dispersion in step 2) with limonene at a volume ratio of 95:5, high-speed shearing at 6000 rpm for 3 min, and then stirring at 300 rpm for 2 h to obtain a limonene emulsion stabilized by the acidified soy protein isolate dispersion;

[0112] 5) mixing the limonene emulsion stabilized by the soy protein isolate dispersion acidified in step 4) with the tannic acid aqueous solution in step 3) in a volume ratio of 1:1, the mixing process is carried out in an ultrasonic water bath equipped with an ice bag, and the mixing time is 30 minutes, to obtain a soy protein isolate-tannic acid carrier dispersion loaded with limonene;

[0113] 6) The limonene-loaded soy protein isolate-tannic acid carrier dispersion was centrifuged (6000 rpm), washed (the centrifuged precipitate was washed with a citric acid-sodium citrate buffer solution of pH=3.0) and resuspended, repeated three times (i.e., the process of centrifugation, washing and resuspending was repeated three times), and then frozen at -18°C for 24 hours, and then frozen in a freeze dryer for 48 hours to obtain a limonene-loaded soy protein isolate-tannic acid carrier with good dispersibility, recorded as soy protein isolate-tannic acid@limonene carrier.

[0114] Example 3

[0115] A preparation method of a soy protein isolate-tannic acid@limonene carrier:

[0116] Same as Example 2, except that the concentration of the tannic acid aqueous solution in step 3) is 60 mg / mL.

[0117] Comparative Example 4

[0118] A preparation method of a soy protein isolate-tannic acid@limonene carrier:

[0119] Same as Example 2, except that the concentration of the tannic acid aqueous solution in step 3) is 15 mg / mL.

[0120] Comparative Example 5

[0121] A preparation method of a soy protein isolate-tannic acid@limonene carrier:

[0122] Same as Example 2, except that the concentration of the tannic acid aqueous solution in step 3) is 7.5 mg / mL.

[0123] Comparative Example 6

[0124] A preparation method of a soy protein isolate-tannic acid@limonene carrier:

[0125] Same as Example 2, except that the concentration of the tannic acid aqueous solution in step 3) is 3.75 mg / mL.

[0126] Comparative Example 7

[0127] A preparation method of a soy protein isolate-tannic acid@limonene carrier:

[0128] Same as Example 2, except that the concentration of the tannic acid aqueous solution in step 3) is 1.875 mg / mL.

[0129] Comparative Example 8

[0130] A method for preparing a soy protein isolate-limonene carrier:

[0131] The same as Example 2, except that no tannic acid aqueous solution is added, and the mixture is directly freeze-dried without centrifugation, washing and resuspension.

[0132] Experimental Example 3

[0133] This experimental example aims to compare the encapsulation efficiency and loading rate of the carriers obtained in Examples 2-3 and Comparative Examples 4-8, so as to determine the encapsulation effect of different composites (i.e., carriers prepared from tannic acid aqueous solutions of different concentrations) on limonene.

[0134] 10 mL of cyclohexane was added to 1 g of the dried carriers of Examples 2-3 and Comparative Examples 4-8, and limonene was extracted from the carriers using an ultrasonic cell disruptor equipped with a Φ3, 1 / 8', 250 μm micro-head and measured. Subsequently, the absorbance of the extract was recorded at 236 nm using an ultraviolet spectrophotometer to determine the content of limonene, and the loading rate was converted according to the formula. The encapsulation efficiency and loading rate were calculated as follows:

[0135] Encapsulation efficiency (%) = (m0-C0×V0) / m0×100%

[0136] Load factor (%) = load factor × m2 / m0 × 100%

[0137] Wherein, m0 is the mass of limonene added (g), m2 is the mass of the obtained sample (g), C0 is the measured limonene concentration (g / mL), and V0 is the volume of cyclohexane added (10 mL).

[0138] The results are shown in Table 4.

[0139] Table 4 Encapsulation efficiency and loading rate of carriers of Examples 2-3 and Comparative Examples 4-8

[0140] Example 2 Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Encapsulation rate / % 40.38±1.28 56.21±2.51 5.53±0.28 7.49±0.36 1.23±0.04 0.78±0.06 nd Load rate / % 45.60±1.63 44.95±2.31 9.80±0.52 9.84±0.92 5.36±0.40 3.90±0.33 nd

[0141] Note: In Table 4, nd means not measured.

[0142] As shown in Table 4, the encapsulation efficiency and loading rate of the soy protein isolate-tannic acid @ limonene carrier obtained in Examples 2 and 3 are significantly higher than those in Comparative Examples 4-8. The scanning electron microscopy image of the soy protein isolate-tannic acid @ limonene carrier material with a tannic acid concentration of 30 mg / mL in Example 1 at a size of 5 μm is shown in Table 4. Figure 3 The scanning electron microscopy image of the soy protein isolate-tannic acid@limonene carrier material with a tannic acid concentration of 30 mg / mL in Example 1 at a size of 1 μm is shown in FIG. Figure 4 , combined with Figure 3 and Figure 4 Microstructure It can be considered that the coral-like microstructure has a crucial influence on the encapsulation of limonene. It can be considered that the complex with a concentration of 30 mg / mL or more of tannic acid has a good encapsulation rate and loading rate. Compared with the currently common cyclodextrin method and complex coacervation method, the carriers of Examples 2 and 3 of the present invention have extremely high encapsulation rates and loading rates.

[0143] Example 4

[0144] A method for preparing a camphene-loaded soy protein isolate-tannic acid carrier:

[0145] Step 1) to step 3) are the same as in Example 2;

[0146] 4) the acidified soy protein isolate dispersion of step 2) is mixed with amphene with a volume ratio of 90:10, with 6000rpm rotating speed high speed shearing 3min, then with 300rpm rotating speed stirring 2h, obtain the stable amphene emulsion of acidified soy protein isolate dispersion;

[0147] 5) the amphene emulsion of the acidified soy protein isolate dispersion liquid of step 4) and the tannic acid aqueous solution of step 3) are mixed with a 1:1 volume ratio, and mixing process is carried out in an ultrasonic water bath where an ice bag is housed, and the mixing time is 30min, namely obtains the soy protein isolate-tannic acid carrier dispersion liquid of load amphene;

[0148] 6) with the soy protein isolate-tannic acid carrier dispersion liquid of load amphene through centrifugal, washing and resuspending (centrifugal, washing and resuspending process are with embodiment 2, the same below), after triplicate, at-18 ℃ of freezing 24h, freezing 48h in freeze drier subsequently to obtain the soy protein isolate-tannic acid carrier of load amphene with good dispersibility, be designated as soy protein isolate-tannic acid@camphene carrier.

[0149] The soy protein isolate-tannic acid @ camphene carrier prepared in this embodiment was stored at room temperature for 30 days after freeze drying without caking. By smelling and comparing with the camphene standard sample, the soy protein isolate-tannic acid @ camphene carrier has the characteristic smell of camphene.

[0150] Example 5

[0151] A method for preparing a linalool-loaded soy protein isolate-tannic acid carrier:

[0152] Step 1)-step 2) are the same as in Example 2;

[0153] 3) dispersing tannic acid in deionized water at a concentration of 45 mg / mL, using an ultrasonic water bath at 25° C. to assist dispersion, obtaining a tannic acid solution, and using 1 M hydrochloric acid to accurately adjust the pH of the tannic acid solution to 3.0 to obtain a tannic acid aqueous solution, which was stored away from light;

[0154] 4) mixing the soy protein isolate dispersion acidified in step 2) with linalool at a volume ratio of 92:8, high-speed shearing at a speed of 6000 rpm for 3 min, and then stirring at a speed of 500 rpm for 2 h to obtain a linalool emulsion stabilized by the acidified soy protein isolate dispersion;

[0155] 5) mixing the linalool emulsion stabilized by the soy protein isolate dispersion acidified in step 4) with the tannic acid aqueous solution in step 3) in a volume ratio of 1:1, the mixing process is carried out in an ultrasonic water bath equipped with an ice bag, and the mixing time is 30 minutes, to obtain a soy protein isolate-tannic acid carrier dispersion loaded with linalool;

[0156] 6) The linalool-loaded soy protein isolate-tannic acid carrier dispersion was centrifuged, washed and resuspended three times, and then frozen at -18°C for 24 hours, and then frozen in a freeze dryer for 48 hours to obtain a linalool-loaded soy protein isolate-tannic acid carrier with good dispersibility, recorded as soy protein isolate-tannic acid@linalool carrier.

[0157] The soy protein isolate-tannic acid@linalool carrier of this embodiment was stored at room temperature for 30 days after freeze-drying without agglomeration. By olfactory comparison with the linalool standard sample, the soy protein isolate-tannic acid@linalool carrier had the characteristic odor of linalool.

[0158] Example 6

[0159] A preparation method of a geraniol-loaded soy protein isolate-tannic acid carrier:

[0160] Step 1)-step 2) are the same as in Example 5;

[0161] 3) dispersing tannic acid in deionized water at a concentration of 100 mg / mL, assisting dispersion by an ultrasonic water bath at 25° C. to obtain a tannic acid solution, and accurately adjusting the pH of the tannic acid solution to 2.0 using 1 M citric acid to obtain a tannic acid aqueous solution, which was stored away from light;

[0162] 4) mixing the acidified soy protein isolate dispersion in step 2) with geraniol at a volume ratio of 85:15, high-speed shearing at 6000 rpm for 3 min, and then stirring at 500 rpm for 2 h to obtain a geraniol emulsion stabilized by the acidified soy protein isolate dispersion;

[0163] 5) mixing the geraniol emulsion stabilized by the soy protein isolate dispersion acidified in step 4) with the tannic acid aqueous solution in step 3) at a volume ratio of 1:1, the mixing process is carried out in an ultrasonic water bath equipped with an ice bag, and the mixing time is 30 minutes, to obtain a soy protein isolate-tannic acid carrier dispersion loaded with geraniol;

[0164] 6) The soy protein isolate-tannic acid carrier dispersion loaded with geraniol was centrifuged, washed and resuspended three times, and then frozen at -18°C for 24 hours, and then frozen in a freeze dryer for 48 hours to obtain a geraniol-loaded soy protein isolate-tannic acid carrier with good dispersibility, which was recorded as soy protein isolate-tannic acid@geraniol carrier.

[0165] The soy protein isolate-tannic acid@geraniol carrier of this embodiment was stored at room temperature for 30 days after freeze-drying without agglomeration. By olfactory comparison with the geraniol standard sample, the soy protein isolate-tannic acid@geraniol carrier had the characteristic odor of geraniol.

[0166] Example 7

[0167] A method for preparing a benzyl acetate-loaded soybean protein isolate-tannic acid carrier:

[0168] Step 1)-step 2) are the same as in Example 5;

[0169] 3) Disperse tannic acid in deionized water at a concentration of 0.001 mg / mL, and use an ultrasonic water bath at 25°C to assist dispersion to obtain a tannic acid solution. Use 1M hydrochloric acid to accurately adjust the pH of the tannic acid solution to 4.6 to obtain a tannic acid aqueous solution, and store it away from light.

[0170] 4) mixing the acidified soy protein isolate dispersion in step 2) with benzyl acetate at a volume ratio of 95:5, high-speed shearing at 7000 rpm for 3 min, and then stirring at 300 rpm for 2 h to obtain a benzyl acetate emulsion stabilized by the acidified soy protein isolate dispersion;

[0171] 5) mixing the benzyl acetate emulsion stabilized by the soy protein isolate dispersion acidified in step 4) with the tannic acid aqueous solution in step 3) at a volume ratio of 1:1, the mixing process is carried out in an ultrasonic water bath equipped with an ice bag, and the mixing time is 30 minutes, to obtain a soy protein isolate-tannic acid carrier dispersion loaded with benzyl acetate;

[0172] 6) The benzyl acetate-loaded soy protein isolate-tannic acid carrier dispersion was centrifuged, washed and resuspended three times, and then frozen at -18°C for 24 hours, and then frozen in a freeze dryer for 48 hours to obtain a benzyl acetate-loaded soy protein isolate-tannic acid carrier with good dispersibility, which was recorded as soy protein isolate-tannic acid@benzyl acetate carrier.

[0173] The soy protein isolate-tannic acid@benzyl acetate carrier prepared in this example was stored at room temperature for 30 days after freeze drying without agglomeration. By olfactory comparison with the benzyl acetate standard, the soy protein isolate-tannic acid@benzyl acetate carrier had the characteristic odor of benzyl acetate.

[0174] Example 8

[0175] A method for preparing a soy protein isolate-tannic acid carrier loaded with neryl acetate:

[0176] Step 1) to step 2) are the same as in Example 5, except that the 1M hydrochloric acid in step 3) is replaced with a 1M citric acid-sodium citrate solution;

[0177] 4) mixing the soy protein isolate dispersion acidified in step 2) with neryl acetate at a volume ratio of 95:5, high-speed shearing at a speed of 7000 rpm for 3 min, and then stirring at a speed of 300 rpm for 2 h to obtain a neryl acetate emulsion stabilized by the acidified soy protein isolate dispersion;

[0178] 5) mixing the neryl acetate emulsion stabilized by the soy protein isolate dispersion acidified in step 4) with the tannic acid aqueous solution in step 3) in a volume ratio of 1:1, the mixing process is carried out in an ultrasonic water bath equipped with an ice bag, and the mixing time is 30 minutes, to obtain a soy protein isolate-tannic acid carrier dispersion loaded with neryl acetate;

[0179] 6) The soy protein isolate-tannic acid carrier dispersion loaded with neryl acetate was centrifuged, washed and resuspended for three times, and then frozen at -18°C for 24 hours, and then frozen in a freeze dryer for 48 hours to obtain a soy protein isolate-tannic acid carrier loaded with neryl acetate with good dispersibility, which was recorded as soy protein isolate-tannic acid@neryl acetate carrier.

[0180] The soy protein isolate-tannic acid@neryl acetate carrier prepared in this embodiment was stored at room temperature for 30 days after freeze drying without caking. By olfactory comparison with the neryl acetate standard sample, the soy protein isolate-tannic acid@neryl acetate carrier had the characteristic odor of neryl acetate.

[0181] Example 9

[0182] A method for preparing a eugenol-loaded soy protein isolate-tannic acid carrier:

[0183] Step 1) to step 2) are the same as in Example 5, except that the 1M hydrochloric acid in step 3) is replaced with 1M tartaric acid;

[0184] 4) mixing the acidified soy protein isolate dispersion of step 2) with eugenol at a volume ratio of 95:5, high-speed shearing at 6000 rpm for 3 min, and then stirring at 300 rpm for 2 h;

[0185] 5) mixing the eugenol emulsion stabilized by the soy protein isolate dispersion acidified in step 4) with the tannic acid aqueous solution in step 3) in a volume ratio of 1:1, the mixing process is carried out in an ultrasonic water bath equipped with an ice bag, and the mixing time is 30 minutes, to obtain a soy protein isolate-tannic acid carrier dispersion loaded with eugenol;

[0186] 6) The soy protein isolate-tannic acid carrier dispersion loaded with eugenol was centrifuged, washed and resuspended three times, and then frozen at -18°C for 24 hours, and then frozen in a freeze dryer for 48 hours to obtain a soy protein isolate-tannic acid carrier loaded with eugenol with good dispersibility, which was recorded as soy protein isolate-tannic acid@eugenol carrier.

[0187] The soy protein isolate-tannic acid@eugenol carrier prepared in this example was stored at room temperature for 30 days after freeze drying without agglomeration. By olfactory comparison with the eugenol standard sample, the soy protein isolate-tannic acid@eugenol carrier had the characteristic odor of eugenol.

[0188] Example 10

[0189] A method for preparing a vanillin-loaded soybean protein isolate-tannic acid carrier:

[0190] Step 1) to step 2) are the same as in Example 5, except that the 1 M hydrochloric acid in step 3) is replaced with 1 M malic acid;

[0191] 4) Dispersing vanillin in triethyl citrate at a mass ratio of 5%, stirring until completely dispersed, to obtain a vanillin dilution;

[0192] 5) mixing the acidified soy protein isolate dispersion in step 2) with the vanillin dilution at a volume ratio of 95:5, high-speed shearing at 6000 rpm for 3 min, and then stirring at 300 rpm for 2 h to obtain an acidified soy protein isolate dispersion-stabilized vanillin dilution emulsion;

[0193] 6) mixing the vanillin dilution emulsion stabilized by the acidified soy protein isolate dispersion in step 4) with the tannic acid aqueous solution in step 3) at a volume ratio of 1:1, and the mixing process is carried out in an ultrasonic water bath equipped with an ice bag for 30 minutes to obtain a soy protein isolate-tannic acid carrier dispersion loaded with vanillin;

[0194] 7) The vanillin-loaded soy protein isolate-tannic acid carrier dispersion was centrifuged, washed and resuspended three times, and then frozen at -18°C for 24 hours, and then frozen in a freeze dryer for 48 hours to obtain a vanillin-loaded soy protein isolate-tannic acid carrier with good dispersibility, recorded as soy protein isolate-tannic acid@vanillin carrier.

[0195] The soy protein isolate-tannic acid @ vanillin carrier prepared in this example was stored at room temperature for 30 days after freeze drying without agglomeration. By olfactory comparison with the vanillin dilution standard sample, the soy protein isolate-tannic acid @ vanillin carrier had the characteristic odor of vanillin.

[0196] Embodiment 11

[0197] A method for preparing a soy protein isolate-tannic acid carrier loaded with ethyl maltol:

[0198] Step 1) is the same as in Example 5;

[0199] 2) using 1 M hydrochloric acid to accurately adjust the pH of the soy protein isolate dispersion to 4.3, stirring at room temperature for 4 hours, and refrigerating at 4° C. overnight to obtain an acidified soy protein isolate dispersion;

[0200] Step 3) is the same as in Example 5;

[0201] 4) dispersing ethyl maltol in medium-chain fatty acid glyceride at a mass ratio of 30%, stirring until completely dispersed, to obtain ethyl maltol dilution;

[0202] 5) mixing the soy protein isolate dispersion acidified in step 2) with the ethyl maltol diluent at a volume ratio of 95:5, high-speed shearing at a speed of 6000 rpm for 3 minutes, and then stirring at a speed of 300 rpm for 2 hours to obtain an ethyl maltol diluent emulsion stabilized by the acidified soy protein isolate dispersion;

[0203] 6) mixing the ethyl maltol dilution emulsion stabilized by the acidified soy protein isolate dispersion in step 4) with the tannic acid aqueous solution in step 3) at a volume ratio of 1:1, the mixing process is carried out in an ultrasonic water bath equipped with an ice bag, and the mixing time is 30 minutes, to obtain a soy protein isolate-tannic acid carrier dispersion loaded with ethyl maltol;

[0204] 7) The soy protein isolate-tannic acid carrier dispersion loaded with ethyl maltol was centrifuged, washed and resuspended three times, and then frozen at -18°C for 24 hours, and then frozen in a freeze dryer for 48 hours to obtain a soy protein isolate-tannic acid carrier loaded with ethyl maltol with good dispersibility, which was recorded as soy protein isolate-tannic acid@ethyl maltol carrier.

[0205] The soy protein isolate-tannic acid@ethyl maltol carrier prepared in this example was stored at room temperature for 30 days after freeze drying without agglomeration. By olfactory comparison with the ethyl maltol dilution standard sample, the soy protein isolate-tannic acid@ethyl maltol carrier had the characteristic smell of vanillin.

[0206] Example 12

[0207] A method for preparing a menthol-loaded soy protein isolate-tannic acid carrier:

[0208] Step 1) is the same as in Example 5;

[0209] 2) using 1 M hydrochloric acid to accurately adjust the pH of the soy protein isolate dispersion to 2.0, stirring at room temperature for 4 hours, and refrigerating at 4° C. overnight to obtain an acidified soy protein isolate dispersion;

[0210] Step 3) is the same as in Example 5;

[0211] 4) mixing the acidified soy protein isolate dispersion in step 2) with molten menthol at a volume ratio of 97:3, high-speed shearing at a speed of 10000 rpm for 5 minutes, and then stirring at a speed of 700 rpm for 2 hours;

[0212] 5) mixing the menthol emulsion stabilized by the soy protein isolate dispersion acidified in step 4) with the tannic acid aqueous solution in step 3) in a volume ratio of 1:1, the mixing process is carried out in an ultrasonic water bath equipped with an ice bag, and the mixing time is 30 minutes, to obtain a menthol-loaded soy protein isolate-tannic acid carrier dispersion;

[0213] 6) The menthol-loaded soy protein isolate-tannic acid carrier dispersion was centrifuged, washed and resuspended three times, and then frozen at -18°C for 24 hours, and then frozen in a freeze dryer for 48 hours to obtain a menthol-loaded soy protein isolate-tannic acid carrier with good dispersibility, which was recorded as soy protein isolate-tannic acid@menthol carrier.

[0214] The soy protein isolate-tannic acid@menthol carrier prepared in this example was stored at room temperature for 30 days after freeze drying without agglomeration. By olfactory comparison with the menthol standard sample, the soy protein isolate-tannic acid@eugenol carrier had the characteristic odor of menthol.

[0215] Example 13

[0216] A method for preparing a soy protein isolate-tannic acid carrier loaded with lemon essential oil:

[0217] Step 1) to step 3) are the same as in Example 5;

[0218] 4) mixing the acidified soy protein isolate dispersion in step 2) with lemon essential oil in a volume ratio of 95:5, high-speed shearing at 6000 rpm for 3 min, and then stirring at 300 rpm for 2 h;

[0219] 5) mixing the lemon essential oil emulsion stabilized by the soy protein isolate dispersion acidified in step 4) with the tannic acid aqueous solution in step 3) in a volume ratio of 1:1, and mixing in an ultrasonic water bath equipped with an ice bag for 30 minutes to obtain a soy protein isolate-tannic acid carrier dispersion loaded with lemon essential oil;

[0220] 6) The soy protein isolate-tannic acid carrier dispersion loaded with lemon essential oil was centrifuged, washed and resuspended three times, and then frozen at -18°C for 24 hours, and then frozen in a freeze dryer for 48 hours to obtain a soy protein isolate-tannic acid carrier loaded with lemon essential oil with good dispersibility, which was recorded as soy protein isolate-tannic acid@lemon essential oil carrier.

[0221] The soy protein isolate-tannic acid @ lemon essential oil carrier prepared in this example was stored at room temperature for 30 days after freeze drying without agglomeration. The characteristic peaks of the spectra of the two were consistent and no obvious miscellaneous peaks appeared by comparing with lemon essential oil through a rapid electronic nose, indicating that the soy protein isolate-tannic acid @ lemon essential oil carrier has a good stabilizing effect and oxidative stability on lemon essential oil.

[0222] Embodiment 14

[0223] A preparation method of a soy protein isolate-tannic acid carrier loaded with rose extract:

[0224] Step 1) to step 3) are the same as in Example 5;

[0225] 4) Rose extract (from the Daily Chemical Fragrance Laboratory of the Department of Flavors, Fragrances and Cosmetics of Shanghai University of Technology) was dispersed in a 1:1 mixed solvent of propylene glycol and medium-chain fatty acid glycerides at a mass ratio of 30%, and stirred until completely dispersed to obtain a rose extract dilution;

[0226] 5) mixing the acidified soy protein isolate dispersion in step 2) with the rose extract dilution at a volume ratio of 95:5, high-speed shearing at 6000 rpm for 3 min, and then stirring at 300 rpm for 2 h;

[0227] 6) mixing the rose extract dilution emulsion stabilized by the soy protein isolate dispersion acidified in step 4) with the tannic acid aqueous solution in step 3) at a volume ratio of 1:1, and mixing in an ultrasonic water bath equipped with an ice bag for 30 minutes to obtain a soy protein isolate-tannic acid carrier dispersion loaded with rose extract;

[0228] 7) The soy protein isolate-tannic acid carrier dispersion loaded with rose extract was centrifuged, washed and resuspended three times, and then frozen at -18°C for 24 hours, and then frozen in a freeze dryer for 48 hours to obtain a soy protein isolate-tannic acid carrier loaded with rose extract with good dispersibility, which was recorded as soy protein isolate-tannic acid@rose extract carrier.

[0229] The soy protein isolate-tannic acid@rose extract carrier prepared in this example was stored at room temperature for 30 days after freeze-drying without agglomeration. The characteristic peaks of the spectra of the two were consistent and no obvious miscellaneous peaks appeared by comparing with the rose extract through the rapid electronic nose, indicating that the soy protein isolate-tannic acid@rose extract carrier has good stabilizing effect and oxidative stability on rose extract.

[0230] Embodiment 15

[0231] A method for preparing a soy protein isolate-tannic acid carrier loaded with milk flavor, wherein the milk flavor is obtained from the edible flavor laboratory of the flavor, flavor and cosmetics department of Shanghai University of Technology, and the solvent of the milk flavor is dipropylene glycol:

[0232] Step 1) to step 3) are the same as in Example 5;

[0233] 4) mixing the acidified soy protein isolate dispersion in step 2) with milk flavor in a volume ratio of 70:30, high-speed shearing at a speed of 10000 rpm for 3 min, and then stirring at a speed of 300 rpm for 2 h;

[0234] 5) mixing the milk flavor emulsion stabilized by the acidified soy protein isolate dispersion in step 4) with the tannic acid aqueous solution in step 3) in a volume ratio of 1:1, the mixing process is carried out in an ultrasonic water bath equipped with an ice bag, and the mixing time is 30 minutes, to obtain a soy protein isolate-tannic acid carrier dispersion loaded with geraniol;

[0235] 6) The soy protein isolate-tannic acid carrier dispersion loaded with milk flavor was centrifuged, washed and resuspended, repeated three times, and then frozen at -18°C for 24 hours, and then frozen in a freeze dryer for 48 hours to obtain a soy protein isolate-tannic acid carrier loaded with milk flavor with good dispersibility, recorded as soy protein isolate-tannic acid@geraniol carrier.

[0236] The soy protein isolate-tannic acid@milk flavor carrier prepared in this example was stored at room temperature for 30 days after freeze drying without agglomeration. By olfactory comparison with the milk flavor standard sample, the soy protein isolate-tannic acid@geraniol carrier had the characteristic smell of milk flavor.

[0237] Example 16

[0238] A method for preparing a soybean protein isolate-tannic acid carrier loaded with coffee flavor, wherein the coffee flavor is obtained from the edible flavor laboratory of the Department of Flavors, Flavors and Cosmetics of Shanghai University of Technology, and the solvent of the coffee flavor is medium-chain fatty acid glyceride:

[0239] Step 1) to step 3) are the same as in Example 5;

[0240] 4) mixing the acidified soy protein isolate dispersion in step 2) with coffee essence in a volume ratio of 80:20, high-speed shearing at 5000 rpm for 3 min, and then stirring at 300 rpm for 2 h;

[0241] 5) mixing the coffee flavor emulsion stabilized by the soy protein isolate dispersion acidified in step 4) and the tannic acid aqueous solution in step 3) in a volume ratio of 1:1, and mixing in an ultrasonic water bath equipped with an ice bag for 30 minutes to obtain a soy protein isolate-tannic acid carrier dispersion loaded with coffee flavor;

[0242] 6) The coffee flavor-loaded soy protein isolate-tannic acid carrier dispersion was centrifuged, washed and resuspended three times, and then frozen at -18°C for 24 hours, and then frozen in a freeze dryer for 48 hours to obtain a coffee flavor-loaded soy protein isolate-tannic acid carrier with good dispersibility, recorded as soy protein isolate-tannic acid@coffee flavor carrier.

[0243] The soy protein isolate-tannic acid@coffee flavor carrier prepared in this example was stored at room temperature for 30 days after freeze drying without agglomeration. By olfactory comparison with the coffee flavor standard sample, the soy protein isolate-tannic acid@coffee flavor carrier had the characteristic smell of coffee flavor.

[0244] Embodiment 17

[0245] A method for preparing a soybean protein isolate-tannic acid carrier loaded with dark tea peanut flavor, wherein the dark tea peanut flavor is obtained from the edible flavor laboratory of the flavor, flavor and cosmetics department of Shanghai University of Technology, and the solvent of the dark tea peanut flavor is a mixture of dipropylene glycol and triethyl citrate in a mass ratio of 3:1:

[0246] Step 1) to step 3) are the same as in Example 5;

[0247] 4) mixing the acidified soy protein isolate dispersion obtained in step 2) with dark tea peanut essence in a volume ratio of 83:17, high-speed shearing at 8000 rpm for 2 min, and then stirring at 600 rpm for 2 h;

[0248] 5) The dark tea peanut flavor emulsion stabilized by the soy protein isolate dispersion acidified in step 4) is mixed with the tannic acid aqueous solution in step 3) at a volume ratio of 1:1, and the mixing process is carried out in an ultrasonic water bath equipped with an ice bag for 30 minutes to obtain a soy protein isolate-tannic acid carrier dispersion loaded with dark tea peanut flavor;

[0249] 6) The soy protein isolate-tannic acid carrier dispersion loaded with dark tea peanut flavor was centrifuged, washed and resuspended three times, and then frozen at -18°C for 24 hours, and then frozen in a freeze dryer for 48 hours to obtain a soy protein isolate-tannic acid carrier loaded with dark tea peanut flavor with good dispersibility, recorded as soy protein isolate-tannic acid@dark tea peanut flavor carrier.

[0250] The soy protein isolate-tannic acid @ dark tea peanut flavor carrier prepared in this example was stored at room temperature for 30 days after freeze-drying without agglomeration. By olfactory comparison with the dark tea peanut flavor standard sample, the soy protein isolate-tannic acid @ dark tea peanut flavor carrier has the characteristic smell of dark tea peanut flavor. By comparing with dark tea peanut flavor through a fast electronic nose, the characteristic peaks of the spectra of the two are consistent and no obvious miscellaneous peaks appear, indicating that the soy protein isolate-tannic acid @ dark tea peanut flavor carrier has good stabilization and oxidative stability on dark tea peanut flavor.

[0251] Embodiment 18

[0252] A method for preparing a soy protein isolate-tannic acid carrier loaded with roast beef flavor, wherein the roast beef flavor is obtained from the edible flavor laboratory of the flavor, flavor and cosmetics department of Shanghai University of Technology, and the solvent of the roast beef flavor is medium-chain fatty acid glyceride:

[0253] Step 1) to step 3) are the same as in Example 5;

[0254] 4) mixing the acidified soy protein isolate dispersion obtained in step 2) with roast beef flavor in a volume ratio of 80:20, high-speed shearing at 5000 rpm for 3 min, and then stirring at 300 rpm for 2 h;

[0255] 5) mixing the roast beef flavor emulsion stabilized by the soy protein isolate dispersion acidified in step 4) and the tannic acid aqueous solution in step 3) in a volume ratio of 1:1, the mixing process is carried out in an ultrasonic water bath equipped with an ice bag, and the mixing time is 30 minutes, to obtain a soy protein isolate-tannic acid carrier dispersion loaded with roast beef flavor;

[0256] 6) The soy protein isolate-tannic acid carrier dispersion loaded with roast beef flavor was centrifuged, washed and resuspended three times, and then frozen at -18°C for 24 hours, and then frozen in a freeze dryer for 48 hours to obtain a soy protein isolate-tannic acid carrier loaded with roast beef flavor with good dispersibility, recorded as soy protein isolate-tannic acid@roast beef flavor carrier.

[0257] The soy protein isolate-tannic acid @ roast beef flavor carrier prepared in this example was stored at room temperature for 30 days after freeze drying without agglomeration. By olfactory comparison with the roast beef flavor standard sample, the soy protein isolate-tannic acid @ roast beef flavor carrier had the characteristic smell of roast beef flavor.

[0258] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for preparing a soy protein isolate-tannic acid@hydrophobic liquid compound, characterized in that: The following steps are involved: 1) dispersing soy protein isolate in water and stirring to obtain a soy protein isolate dispersion; 2) adjusting the pH of the soy protein isolate dispersion to acidic by using an acidity regulator, and stirring uniformly to obtain an acidified soy protein isolate dispersion; 3) dispersing tannic acid in water, and adjusting the pH to acidic with an acidity regulator to obtain a tannic acid aqueous solution; 4) pre-dispersing the acidified soy protein isolate dispersion with a hydrophobic liquid compound to be loaded to obtain an emulsion; 5) mixing the emulsion of step 4) with the tannic acid aqueous solution of step 3), and ultrasonicating in an ice-water bath to obtain a soy protein isolate-tannic acid@hydrophobic liquid compound dispersion; 6) The soy protein isolate-tannic acid@hydrophobic liquid compound dispersion is washed, centrifuged, resuspended, and dried to obtain the soy protein isolate-tannic acid@hydrophobic liquid compound.

2. The method for preparing the soy protein isolate-tannic acid@hydrophobic liquid compound according to claim 1, characterized in that: In step 1), the concentration of the soy protein isolate dispersion is 30-60 mg / mL.

3. The method for preparing the soy protein isolate-tannic acid@hydrophobic liquid compound according to claim 1, characterized in that: In step 2) and step 3), the acidity regulator is one of hydrochloric acid, citric acid, malic acid, tartaric acid and citric acid-sodium citrate solution.

4. The method for preparing the soy protein isolate-tannic acid@hydrophobic liquid compound according to claim 1, characterized in that: In step 2), the pH is adjusted to 2.0-4.

3.

5. The method for preparing the soy protein isolate-tannic acid@hydrophobic liquid compound according to claim 1, characterized in that: In step 3), the pH is adjusted to 2.0-4.

6.

6. The method for preparing the soy protein isolate-tannic acid@hydrophobic liquid compound according to claim 1, characterized in that: In step 3), the concentration of the tannic acid aqueous solution is 0.001-100 mg / mL.

7. The method for preparing the soy protein isolate-tannic acid@hydrophobic liquid compound according to claim 1, characterized in that: In step 5), the volume ratio of the emulsion in step 4) to the tannic acid aqueous solution in step 3) is 1:(1-5).

8. A soy protein isolate-tannic acid@hydrophobic liquid compound, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 7.

9. Use of the soy protein isolate-tannic acid@hydrophobic liquid compound according to claim 8 in the field of spices and flavors.

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