Tea oil with nutty aroma and method for preparing the same

Abstract

The application provides tea oil with nut aroma and a preparation method thereof, and steps are as follows: S1: after the oil tea seed is shelled and crushed, the oil tea seed is reacted with a composite enzyme solution; S2: after the enzyme-degraded tea seed powder is inactivated and cooled, ethanol solution is sprayed, and a double-layer microsphere is added to form a mixed system; S3: the mixed system and the ethanol solution are added into a vacuum extraction tank for extraction; S4: the extract is centrifuged, and a tea seed residue-microsphere mixture and a crude tea oil-ethanol mixed solution are separated, the tea seed residue-microsphere mixture is dried, and the double-layer microsphere is recovered; the crude tea oil-ethanol mixed solution is dehydrated for 20 min to obtain crude tea oil; S5: the recovered double-layer microsphere is placed into a vacuum desorption tank connected with a condensation system for desorption, and the collected aroma concentrated solution is added into the crude tea oil, and after stirring, the mixture is statically placed at 40 DEG C for 30 min, and after degumming, decoloring and degassing, the tea oil with nut aroma is obtained. The prepared tea oil has good color, and while improving the tea oil extraction rate and retaining the nut aroma, the heat-sensitive nutritional components are also fully retained.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to a tea oil with a nutty aroma and its preparation method. Background Technology

[0002] Camellia oil is a woody plant oil produced from the mature seeds of the camellia oleifera plant (commonly known as camellia seeds) through extraction and refining processes. Camellia seeds consist of an outer shell and a kernel, with the kernel being the core part for oil extraction. Camellia oil contains over 90% unsaturated fatty acids, with oleic acid accounting for 70%–80%, linoleic acid for 10%–15%, and saturated fatty acids for only about 10%. Its composition is similar to olive oil, but with a higher smoke point, making it suitable for high-temperature cooking methods such as frying, stir-frying, and deep-frying, and less likely to produce harmful substances. Furthermore, camellia oil is rich in natural active ingredients such as vitamin E, phytosterols, and squalene, and contains no trans fatty acids. Long-term consumption helps regulate blood lipid metabolism and reduce the risk of cardiovascular disease, offering nutritional and health benefits. It can also be widely used in cosmetic raw materials, biodiesel, and other fields. Traditionally, it has also been used for skin moisturizing and minor burn repair, making its applications very diverse. Currently, the main methods for extracting camellia oil include pressing, solvent extraction, and enzymatic extraction. Pressing extracts oil through physical pressure, is simple, and leaves no chemical solvent residue. It is divided into cold pressing and hot pressing. Cold pressing retains active ingredients better but has a low oil yield. While hot pressing increases the oil yield, it results in the loss of some active ingredients due to high-temperature steaming and roasting, and leaves a significant amount of residual oil in the cake. Solvent extraction uses organic solvents such as hexane, offering high raw material utilization and suitability for large-scale production. However, it carries the risk of solvent residue and significant loss of active ingredients. Enzymatic extraction relies on cellulase and protease to break down the cell walls and protein networks of camellia seeds. It is environmentally friendly and has high byproduct utilization. However, the oil in camellia seeds is encapsulated in a dense matrix composed of starch, cellulose, and protein, making it difficult for a single enzyme system to completely break down the complex structure, thus limiting the oil extraction rate. Furthermore, existing extraction methods generally suffer from insufficient retention of nutty aroma, failing to meet consumer demand for the natural flavor of camellia oil and hindering further improvement in its quality.

[0003] To address the shortcomings of existing technologies, this invention provides a method for preparing tea oil that preserves the aroma of nuts. First, tea seeds are pretreated by removing impurities, crushing, and enzymatic hydrolysis to break down the cell walls of the tea seeds. Then, the pretreated tea seed powder is mixed with double-layer microspheres, and the tea oil is extracted and the aroma of nuts is captured using an ultrasonic vacuum method. The tea oil extracted by this method not only preserves the aroma of nuts to the greatest extent but also improves the extraction rate of tea oil. Summary of the Invention

[0004] This invention provides a tea oil with a nutty aroma and its preparation method. The method involves pretreating tea seeds to break down cell walls, mixing them with double-layer microspheres, and then using an ultrasonic vacuum method to extract crude tea oil and capture nutty aroma molecules. The aroma molecules are then added back into the crude tea oil. Finally, the oil is degummed, decolorized, and degassed. This process not only preserves the nutty aroma of the tea oil to the greatest extent but also improves the extraction rate of the tea oil.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned objective is: a method for preparing tea oil with a nutty aroma, comprising the following steps: S1: Remove the shells from the camellia seeds to obtain the kernels. After removing impurities, grind the kernels to 80-100 mesh. Mix the compound enzyme solution and camellia seed powder at 45-50℃, pH 4.8-5.2, and a rotation speed of 50-80 r / min for 2 hours, stirring for 5 minutes every 30 minutes. S2: After enzymatic hydrolysis, the tea seed powder is kept at 80-90℃ for 10-15 minutes to inactivate the enzyme. After cooling to 35-40℃, a 15% ethanol solution is sprayed into the enzymatically hydrolyzed tea seed powder while maintaining a mixing speed of 50-60 r / min. After spraying, double-layer microspheres are added and the mixture is continuously dispersed using an ultrasonic disperser for 10-15 minutes. The dispersed material is then allowed to stand at 35℃ for 20-25 minutes to form a mixed system. S3: Add the mixture and 60% ethanol solution to the vacuum extraction vessel, stir at 80-100 r / min for 5 min to mix evenly, raise the vacuum degree in the vessel to -0.07~-0.08 MPa, maintain for 8-10 min, then raise the temperature to 45-50℃, and extract for 1-1.5 h in a pulse mode with ultrasonic power of 250W, 3s on, 2s off; S4: The extract was centrifuged at 4000-5000 r / min for 15 min to separate the tea seed residue-microsphere mixture and the crude tea oil-ethanol mixture. The tea seed residue-microsphere mixture was dried at 45-50℃, and the double-layer microspheres were recovered after sieving. The crude tea oil-ethanol mixture was transferred to a vacuum deethanolating tank and deethanolated at 60℃ and -0.09 MPa for 20 min to obtain crude tea oil. S5: The recovered double-layer microspheres are placed in a vacuum desorption tank with a condensation system and desorbed at 65℃ and -0.085MPa for 12-15 minutes to collect the aroma concentrate. The aroma concentrate is then added back into the crude tea oil at 45℃ and 80-100r / min. After stirring, the mixture is allowed to stand at 40℃ for 30 minutes to undergo degumming, decolorization, and degassing, resulting in tea oil with a nutty aroma.

[0006] Furthermore, calculated by mass ratio, the composition of the complex enzyme solution in S1 is cellulase: pectinase: water = 3:1:80.

[0007] Furthermore, the mass ratio of the compound enzyme solution to tea seed powder in S1 is (5-8):100.

[0008] Furthermore, the mass ratio of the ethanol aqueous solution and the enzymatically hydrolyzed tea seed powder in S2 is 1:3.

[0009] Furthermore, the amount of bilayer microspheres added in S2 is 7-8.5% of the mass of the enzymatically hydrolyzed tea seed powder.

[0010] Furthermore, the preparation method of the bilayer microspheres in S2 is as follows: S21: Add a 1 mol / L hydrochloric acid solution to the maifan stone powder at a solid-liquid ratio of 1 g: 10 mL, stir in a water bath at 60 °C for 4 h, centrifuge and discard the supernatant, wash the solid repeatedly with deionized water until neutral, dry the washed solid at 105 °C for 6 h, and finally calcine at 350 °C for 2 h. S22: Dissolve β-cyclodextrin in deionized water at 60℃ according to a solid-liquid ratio of 1g:10mL to prepare a β-cyclodextrin solution. Add the maifanite powder treated in S21 to the β-cyclodextrin solution at a solid-liquid ratio of 1:(2-3), ultrasonically disperse for 10min, stir at 60r / min in a 45℃ water bath for 12h, and finally dry at 60℃ to obtain the composite powder. S23: The composite powder was dispersed in a 0.5% polyvinyl alcohol solution at a solid-liquid ratio of 1g:10mL, and sonicated for 5min to form a uniform suspension, which served as the inner aqueous phase; polylactic acid and talc were dissolved together in dichloromethane at a solid-liquid ratio of 2g:0.1g:20mL, and magnetically stirred at 35℃ until completely dissolved, which served as the oil phase; a 2% polyvinyl alcohol solution served as the outer aqueous phase. S24: Slowly drip the inner aqueous phase into the oil phase under high-speed shear at 10000 r / min, and continue high-speed shear emulsification for 2-3 min to form a uniform primary emulsion; pour the primary emulsion into the outer aqueous phase, stir at 250-300 r / min, emulsify at room temperature for 3-4 h, let stand for 30 min after emulsification, transfer the microsphere suspension to a centrifuge tube, centrifuge at 3000 r / min for 5 min, and collect the microsphere precipitate; resuspend the microsphere precipitate with deionized water and wash 2-3 times, freeze-dry the washed microsphere suspension for 24 h to obtain the bilayer microspheres.

[0011] Furthermore, in S24, the volume ratio of the inner aqueous phase to the oil phase is 1:2, and the volume ratio of the primary emulsion to the outer aqueous phase is 1:10.

[0012] Furthermore, the mass ratio of the mixed system and the aqueous ethanol solution in S3 is (2.5-3.5):1.

[0013] Further, the specific treatment methods for degumming, decolorizing, and degassing in S5 are as follows: add a 1% citric acid solution to the crude tea oil with added aroma, stir at 45°C for 15-20 minutes, centrifuge at 3000 r / min for 10-15 minutes to remove the gum; cool to 38°C, add a decolorizing agent, stir for 20-25 minutes, filter, and transfer the decolorized tea oil to a vacuum degassing tank for degassing at 65°C and -0.09 MPa for 15-20 minutes. The decolorizing agent is composed of activated clay and activated carbon in a ratio of 3:1, the amount of citric acid solution added is 1-1.2% of the crude tea oil, and the amount of decolorizing agent added is 1.1-1.2% of the crude tea oil.

[0014] The present invention also discloses tea oil with a nutty aroma prepared by the above method.

[0015] Compared with the prior art, the present invention has the following beneficial effects: In this invention, tea seed powder undergoes enzymatic hydrolysis, with cellulase and pectinase as the core components. The dual action destroys the cell wall structure, promoting the rapid penetration of the subsequent extraction medium into the oil cells, thereby increasing the tea oil extraction rate. This process eliminates the need for high temperature and high pressure, avoiding the loss of heat-sensitive nutrients in the tea oil, and simultaneously creating more space for full contact between the double-layer microspheres and the tea seed powder. The bilayer microspheres in this invention use acidified maifanite powder and β-cyclodextrin as the core, with polylactic acid and talc as the outer layer. The high porosity of the maifanite powder constructs oil-conducting channels, accelerating the diffusion of tea oil into the extraction medium and improving the tea oil extraction rate. β-cyclodextrin specifically captures nutty aroma components (such as tetramethylpyrazine, esters, etc.) in tea oil through its cavity structure. The outer polylactic acid layer provides structural support to prevent microsphere breakage, while talc reduces agglomeration and ensures uniform dispersion of the microspheres. The microspheres are then placed in a vacuum desorption tank. The vacuum environment reduces the system pressure, breaking the interaction between the β-cyclodextrin cavity and the aroma molecules, allowing the gaseous aroma components to escape. Although the aroma exists in a gaseous form, it has the physical properties of being easily liquefied at low temperatures and soluble in tea oil. Through a 0~5℃ low-temperature condensation system connected to the outlet of the vacuum desorption tank, the gaseous aroma molecules are transformed from a gaseous state to a liquid aroma concentrate upon cooling. The aroma concentrate is then added back into the crude tea oil, preserving the nutty aroma of the tea oil to the greatest extent. The enzymatic hydrolysis process of this invention opens channels for oil dissolution, and the ultrasonic vacuum method generates cavitation effect through ultrasonic vibration, impacting tea seed powder particles, further breaking down incompletely enzymatically hydrolyzed cell walls, and promoting oil dissolution. The vacuum environment also reduces the volatilization of aroma to a certain extent. The two processes, together with the double-layer microspheres, form a synergistic system, which, compared with existing processes, achieves the capture of nut aroma and improves the extraction rate of tea oil. Detailed Implementation

[0016] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0017] It should be understood that the following descriptions of the proportions, concentrations, and process parameters of the substances involved in the extraction of tea oil in this invention are preferred embodiments and should not be construed as limiting the scope of protection of the independent claims. The embodiments described are only for explaining the invention and are not intended to limit the scope of the invention. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available food-grade reagents and materials. Example 1

[0018] A method for preparing tea oil with a nutty aroma includes the following steps: S1: Remove the shells from the camellia seeds to obtain the kernels. After removing impurities, grind the kernels to 80 mesh. At 45℃, pH 4.8, and a rotation speed of 50 r / min, mix the compound enzyme solution and camellia seed powder at a mass ratio of 5:100 and perform enzymatic hydrolysis for 2 hours, stirring for 5 minutes every 30 minutes. The composition of the compound enzyme solution is cellulase: pectinase: water = 3:1:80. S2: After enzymatic hydrolysis, the tea seed powder is kept at 80℃ for 10 minutes to inactivate the enzyme. After cooling to 35℃, a 15% ethanol solution is sprayed into the enzymatic hydrolyzed tea seed powder at a mass ratio of 1:3. The mixture is stirred at a speed of 50 r / min while spraying. After spraying, double-layer microspheres are added. The amount of double-layer microspheres added is 7% of the mass of the enzymatic hydrolyzed tea seed powder. The mixture is continuously dispersed using an ultrasonic disperser for 10 minutes. The dispersed material is then allowed to stand at 35℃ for 20 minutes to form a mixed system. The method for preparing the bilayer microspheres is as follows: S21: Add a 1 mol / L hydrochloric acid solution to the maifan stone powder at a solid-liquid ratio of 1 g: 10 mL, stir in a water bath at 60 °C for 4 h, centrifuge and discard the supernatant, wash the solid repeatedly with deionized water until neutral, dry the washed solid at 105 °C for 6 h, and finally calcine at 350 °C for 2 h. S22: Dissolve β-cyclodextrin in deionized water at 60℃ at a solid-liquid ratio of 1g:10mL to prepare a β-cyclodextrin solution. Add the maifanite powder treated in S21 to the β-cyclodextrin solution at a solid-liquid ratio of 1:2, ultrasonically disperse for 10min, stir at 60r / min in a 45℃ water bath for 12h, and finally dry at 60℃ to obtain the composite powder. S23: The composite powder was dispersed in a 0.5% polyvinyl alcohol solution at a solid-liquid ratio of 1g:10mL, and sonicated for 5min to form a uniform suspension, which served as the inner aqueous phase; polylactic acid and talc were dissolved together in dichloromethane at a solid-liquid ratio of 2g:0.1g:20mL, and magnetically stirred at 35℃ until completely dissolved, which served as the oil phase; a 2% polyvinyl alcohol solution served as the outer aqueous phase. S24: The inner aqueous phase was slowly dripped into the oil phase at a volume ratio of 1:2 under high-speed shear at 10000 r / min, and emulsified under high-speed shear for 2 min to form a uniform primary emulsion. The primary emulsion was poured into the outer aqueous phase at a volume ratio of 1:10, stirred at 250 r / min, and emulsified at room temperature for 3 h. After emulsification, the mixture was allowed to stand for 30 min. The microsphere suspension was then transferred to a centrifuge tube and centrifuged at 3000 r / min for 5 min to collect the microsphere precipitate. The microsphere precipitate was resuspended and washed twice with deionized water. The washed microsphere suspension was freeze-dried for 24 h to obtain the bilayer microspheres.

[0019] S3: Add the mixture and 60% ethanol solution to the vacuum extraction vessel at a mass ratio of 2.5:1. Stir at 80 r / min for 5 min to mix evenly. Increase the vacuum in the vessel to -0.07 MPa and maintain it for 8 min. Then raise the temperature to 45℃ and extract for 1 h in a pulse mode with an ultrasonic power of 250W, 3s on and 2s off. S4: The extract was centrifuged at 4000 r / min for 15 min to separate the tea seed residue-microsphere mixture and the crude tea oil-ethanol mixture. The tea seed residue-microsphere mixture was dried at 45℃, and the double-layer microspheres were recovered after sieving. The crude tea oil-ethanol mixture was transferred to a vacuum deethanolating tank and deethanolated at 60℃ and -0.09 MPa for 20 min to obtain crude tea oil. S5: The recovered double-layer microspheres are placed in a vacuum desorption tank equipped with a condensation system and desorbed at 65℃ and -0.085MPa for 12 minutes to collect the aroma concentrate. The aroma concentrate is then added back to the crude tea oil at 45℃ and 80r / min. After stirring, the mixture is allowed to stand at 40℃ for 30 minutes. A 1% citric acid solution is added to the crude tea oil with added aroma, and the mixture is stirred at 45℃ for 15 minutes. The mixture is then centrifuged at 3000r / min for 10 minutes to remove the gum. The mixture is cooled to 38℃, and a decolorizing agent is added. After stirring for 20 minutes, the mixture is filtered. The decolorizing agent consists of activated clay and activated carbon in a ratio of 3:1. The amount of citric acid solution added is 1% of the crude tea oil, and the amount of decolorizing agent added is 1.1% of the crude tea oil. The decolorized tea oil is then transferred to a vacuum degassing tank and degassed at 65℃ and -0.09MPa for 15 minutes to obtain tea oil with a nutty aroma. Example 2

[0020] A method for preparing tea oil with a nutty aroma includes the following steps: S1: Remove the shells from the camellia seeds to obtain the kernels. After removing impurities, grind the kernels to 85 mesh. At 47℃, pH 4.9, and a rotation speed of 55 r / min, mix the compound enzyme solution and camellia seed powder at a mass ratio of 5:100 and perform enzymatic hydrolysis for 2 hours, stirring for 5 minutes every 30 minutes. The composition of the compound enzyme solution is cellulase: pectinase: water = 3:1:80. S2: After enzymatic hydrolysis, the tea seed powder was kept at 83℃ for 11 minutes to inactivate the enzyme. After cooling to 37℃, a 15% ethanol solution was sprayed into the enzymatic hydrolyzed tea seed powder at a mass ratio of 1:3. The mixture was sprayed while maintaining a speed of 52 r / min. After spraying, double-layer microspheres were added. The amount of double-layer microspheres added was 7.2% of the mass of the enzymatic hydrolyzed tea seed powder. The mixture was continuously dispersed using an ultrasonic disperser for 12 minutes. The dispersed material was then allowed to stand at 35℃ for 22 minutes to form a mixed system. The method for preparing the bilayer microspheres is as follows: S21: Add a 1 mol / L hydrochloric acid solution to the maifan stone powder at a solid-liquid ratio of 1 g: 10 mL, stir in a water bath at 60 °C for 4 h, centrifuge and discard the supernatant, wash the solid repeatedly with deionized water until neutral, dry the washed solid at 105 °C for 6 h, and finally calcine at 350 °C for 2 h. S22: Dissolve β-cyclodextrin in deionized water at 60℃ at a solid-liquid ratio of 1g:10mL to prepare a β-cyclodextrin solution. Add the maifanite powder treated in S21 to the β-cyclodextrin solution at a solid-liquid ratio of 1:2, ultrasonically disperse for 10min, stir at 60r / min in a 45℃ water bath for 12h, and finally dry at 60℃ to obtain the composite powder. S23: The composite powder was dispersed in a 0.5% polyvinyl alcohol solution at a solid-liquid ratio of 1g:10mL, and sonicated for 5min to form a uniform suspension, which served as the inner aqueous phase; polylactic acid and talc were dissolved together in dichloromethane at a solid-liquid ratio of 2g:0.1g:20mL, and magnetically stirred at 35℃ until completely dissolved, which served as the oil phase; a 2% polyvinyl alcohol solution served as the outer aqueous phase. S24: The inner aqueous phase was slowly dripped into the oil phase at a volume ratio of 1:2 under high-speed shear at 10000 r / min, and emulsified under high-speed shear for 2 min to form a uniform primary emulsion. The primary emulsion was poured into the outer aqueous phase at a volume ratio of 1:10, stirred at 260 r / min, and emulsified at room temperature for 3.2 h. After emulsification, the mixture was allowed to stand for 30 min. The microsphere suspension was then transferred to a centrifuge tube and centrifuged at 3000 r / min for 5 min to collect the microsphere precipitate. The microsphere precipitate was resuspended and washed twice with deionized water. The washed microsphere suspension was freeze-dried for 24 h to obtain the bilayer microspheres.

[0021] S3: Add the mixture and 60% ethanol solution to the vacuum extraction vessel at a mass ratio of 2.7:1, stir at 85 r / min for 5 min to mix evenly, raise the vacuum degree in the vessel to -0.075 MPa, maintain for 8.5 min, then raise the temperature to 46℃, and extract for 1.2 h in a pulse mode with ultrasonic power of 250W, 3s on, 2s off; S4: The extract was centrifuged at 4200 r / min for 15 min to separate the tea seed residue-microsphere mixture and the crude tea oil-ethanol mixture. The tea seed residue-microsphere mixture was dried at 46℃, and the double-layer microspheres were recovered after sieving. The crude tea oil-ethanol mixture was transferred to a vacuum deethanolating tank and deethanolated at 60℃ and -0.09 MPa for 20 min to obtain crude tea oil. S5: The recovered double-layer microspheres are placed in a vacuum desorption tank equipped with a condensation system and desorbed at 65℃ and -0.085MPa for 13 minutes to collect the aroma concentrate. The aroma concentrate is then added back into the crude tea oil at 45℃ and 85r / min. After stirring, the mixture is allowed to stand at 40℃ for 30 minutes. A 1% citric acid solution is added to the crude tea oil with added aroma, and the mixture is stirred at 45℃ for 17 minutes. The mixture is then centrifuged at 3000r / min for 12 minutes to remove the gum. The mixture is cooled to 38℃, and a decolorizing agent is added. After stirring for 22 minutes, the mixture is filtered. The decolorizing agent consists of activated clay and activated carbon in a 3:1 ratio. The amount of citric acid solution added is 1.1% of the crude tea oil, and the amount of decolorizing agent added is 1.1% of the crude tea oil. The decolorized tea oil is then transferred to a vacuum degassing tank and degassed at 65℃ and -0.09MPa for 17 minutes to obtain tea oil with a nutty aroma. Example 3

[0022] A method for preparing tea oil with a nutty aroma includes the following steps: S1: Remove the shells from the camellia seeds to obtain the kernels. After removing impurities, grind the kernels to 90 mesh. At 48℃, pH 5.0, and a rotation speed of 65 r / min, mix the compound enzyme solution and camellia seed powder at a mass ratio of 7:100 and perform enzymatic hydrolysis for 2 hours, stirring for 5 minutes every 30 minutes. The composition of the compound enzyme solution is cellulase: pectinase: water = 3:1:80. S2: After enzymatic hydrolysis, the tea seed powder was kept at 85℃ for 13 minutes to inactivate the enzyme. After cooling to 38℃, a 15% ethanol solution was sprayed into the enzymatic hydrolyzed tea seed powder at a mass ratio of 1:3. The mixture was sprayed while maintaining a speed of 55 r / min. After spraying, double-layer microspheres were added. The amount of double-layer microspheres added was 7.5% of the mass of the enzymatic hydrolyzed tea seed powder. The mixture was continuously dispersed using an ultrasonic disperser for 13 minutes. The dispersed material was then allowed to stand at 35℃ for 23 minutes to form a mixed system. The method for preparing the bilayer microspheres is as follows: S21: Add a 1 mol / L hydrochloric acid solution to the maifan stone powder at a solid-liquid ratio of 1 g: 10 mL, stir in a water bath at 60 °C for 4 h, centrifuge and discard the supernatant, wash the solid repeatedly with deionized water until neutral, dry the washed solid at 105 °C for 6 h, and finally calcine at 350 °C for 2 h. S22: Dissolve β-cyclodextrin in deionized water at 60℃ at a solid-liquid ratio of 1g:10mL to prepare a β-cyclodextrin solution. Add the maifanite powder treated in S21 to the β-cyclodextrin solution at a solid-liquid ratio of 1:2.5, ultrasonically disperse for 10min, stir at 60r / min in a 45℃ water bath for 12h, and finally dry at 60℃ to obtain the composite powder. S23: The composite powder was dispersed in a 0.5% polyvinyl alcohol solution at a solid-liquid ratio of 1g:10mL, and sonicated for 5min to form a uniform suspension, which served as the inner aqueous phase; polylactic acid and talc were dissolved together in dichloromethane at a solid-liquid ratio of 2g:0.1g:20mL, and magnetically stirred at 35℃ until completely dissolved, which served as the oil phase; a 2% polyvinyl alcohol solution served as the outer aqueous phase. S24: The inner aqueous phase was slowly dripped into the oil phase at a volume ratio of 1:2 under high-speed shear at 10000 r / min, and emulsified under high-speed shear for 2.5 min to form a uniform primary emulsion; the primary emulsion was poured into the outer aqueous phase at a volume ratio of 1:10, stirred at 280 r / min, and emulsified at room temperature for 3.5 h. After emulsification, the mixture was allowed to stand for 30 min, and the microsphere suspension was transferred to a centrifuge tube and centrifuged at 3000 r / min for 5 min to collect the microsphere precipitate; the microsphere precipitate was resuspended and washed 3 times with deionized water, and the washed microsphere suspension was freeze-dried for 24 h to obtain the bilayer microspheres.

[0023] S3: Add the mixture and 60% ethanol solution to the vacuum extraction vessel at a mass ratio of 3:1, stir at 90 r / min for 5 min to mix evenly, raise the vacuum degree in the vessel to -0.075 MPa, maintain for 9 min, then raise the temperature to 47℃, and extract for 1.3 h in a pulse mode with ultrasonic power of 250W, 3s on, 2s off. S4: The extract was centrifuged at 4500 r / min for 15 min to separate the tea seed residue-microsphere mixture and the crude tea oil-ethanol mixture. The tea seed residue-microsphere mixture was dried at 48℃, and the double-layer microspheres were recovered after sieving. The crude tea oil-ethanol mixture was transferred to a vacuum deethanolating tank and deethanolated at 60℃ and -0.09 MPa for 20 min to obtain crude tea oil. S5: The recovered double-layer microspheres are placed in a vacuum desorption tank with a condensation system and desorbed at 65℃ and -0.085MPa for 14 minutes to collect the aroma concentrate. The aroma concentrate is added back into the crude tea oil at 45℃ and 90r / min, stirred, and then allowed to stand at 40℃ for 30 minutes. A 1% citric acid solution is added to the crude tea oil with added aroma, stirred at 45℃ for 18 minutes, and centrifuged at 3000r / min for 13 minutes to remove the gum. The temperature is lowered to 38℃, a decolorizing agent is added, and the mixture is stirred for 23 minutes and then filtered. The decolorizing agent consists of activated clay and activated carbon in a ratio of 3:1. The amount of citric acid solution added is 1.1% of the crude tea oil, and the amount of decolorizing agent added is 1.15% of the crude tea oil. The decolorized tea oil is transferred to a vacuum degassing tank and degassed at 65℃ and -0.09MPa for 18 minutes to obtain tea oil with a nutty aroma. Example 4

[0024] A method for preparing tea oil with a nutty aroma includes the following steps: S1: Remove the shells from the camellia seeds to obtain the kernels. After removing impurities, grind the kernels to 100 mesh. At 49℃, pH 5.1, and a rotation speed of 70 r / min, mix the compound enzyme solution and camellia seed powder at a mass ratio of 7:100 and perform enzymatic hydrolysis for 2 hours, stirring for 5 minutes every 30 minutes. The composition of the compound enzyme solution is cellulase: pectinase: water = 3:1:80. S2: After enzymatic hydrolysis, the tea seed powder is kept at 87℃ for 10-15 minutes to inactivate the enzyme. After cooling to 38℃, a 15% ethanol solution is sprayed into the enzymatic hydrolyzed tea seed powder at a mass ratio of 1:3 while maintaining a mixing speed of 55 r / min. After spraying, double-layer microspheres are added, with the amount of double-layer microspheres being 8% of the mass of the enzymatic hydrolyzed tea seed powder. The mixture is then continuously dispersed using an ultrasonic disperser for 14 minutes. The dispersed material is then allowed to stand at 35℃ for 23 minutes to form a mixed system. The method for preparing the bilayer microspheres is as follows: S21: Add a 1 mol / L hydrochloric acid solution to the maifan stone powder at a solid-liquid ratio of 1 g: 10 mL, stir in a water bath at 60 °C for 4 h, centrifuge and discard the supernatant, wash the solid repeatedly with deionized water until neutral, dry the washed solid at 105 °C for 6 h, and finally calcine at 350 °C for 2 h. S22: Dissolve β-cyclodextrin in deionized water at 60℃ at a solid-liquid ratio of 1g:10mL to prepare a β-cyclodextrin solution. Add the maifanite powder treated in S21 to the β-cyclodextrin solution at a solid-liquid ratio of 1:3, ultrasonically disperse for 10min, stir at 60r / min in a 45℃ water bath for 12h, and finally dry at 60℃ to obtain the composite powder. S23: The composite powder was dispersed in a 0.5% polyvinyl alcohol solution at a solid-liquid ratio of 1g:10mL, and sonicated for 5min to form a uniform suspension, which served as the inner aqueous phase; polylactic acid and talc were dissolved together in dichloromethane at a solid-liquid ratio of 2g:0.1g:20mL, and magnetically stirred at 35℃ until completely dissolved, which served as the oil phase; a 2% polyvinyl alcohol solution served as the outer aqueous phase. S24: The inner aqueous phase was slowly dripped into the oil phase at a volume ratio of 1:2 under high-speed shear at 10000 r / min, and emulsified under high-speed shear for 3 min to form a uniform primary emulsion. The primary emulsion was poured into the outer aqueous phase at a volume ratio of 1:10, stirred at 280 r / min, and emulsified at room temperature for 3.8 h. After emulsification, the mixture was allowed to stand for 30 min. The microsphere suspension was then transferred to a centrifuge tube and centrifuged at 3000 r / min for 5 min to collect the microsphere precipitate. The microsphere precipitate was resuspended and washed 3 times with deionized water. The washed microsphere suspension was freeze-dried for 24 h to obtain the bilayer microspheres.

[0025] S3: Add the mixture and 60% ethanol solution to the vacuum extraction vessel at a mass ratio of 3:1, stir at 90 r / min for 5 min to mix evenly, raise the vacuum degree in the vessel to -0.08 MPa, maintain for 9 min, then raise the temperature to 48℃, and extract for 1.3 h in a pulse mode with ultrasonic power of 250W, 3s on, 2s off. S4: The extract was centrifuged at 5000 r / min for 15 min to separate the tea seed residue-microsphere mixture and the crude tea oil-ethanol mixture. The tea seed residue-microsphere mixture was dried at 47℃, and the double-layer microspheres were recovered after sieving. The crude tea oil-ethanol mixture was transferred to a vacuum deethanolating tank and deethanolated at 60℃ and -0.09 MPa for 20 min to obtain crude tea oil. S5: The recovered double-layer microspheres are placed in a vacuum desorption tank equipped with a condensation system and desorbed at 65℃ and -0.085MPa for 14 minutes to collect the aroma concentrate. The aroma concentrate is then added back into the crude tea oil at 45℃ and 95r / min. After stirring, the mixture is allowed to stand at 40℃ for 30 minutes. A 1% citric acid solution is added to the crude tea oil with added aroma, and the mixture is stirred at 45℃ for 24 minutes. The mixture is then centrifuged at 3000r / min for 14 minutes to remove the gum. The mixture is cooled to 38℃, and a decolorizing agent is added. After stirring for 24 minutes, the mixture is filtered. The decolorizing agent consists of activated clay and activated carbon in a 3:1 ratio. The amount of citric acid solution added is 1.2% of the crude tea oil, and the amount of decolorizing agent added is 1.2% of the crude tea oil. The decolorized tea oil is then transferred to a vacuum degassing tank and degassed at 65℃ and -0.09MPa for 18 minutes to obtain tea oil with a nutty aroma. Example 5

[0026] A method for preparing tea oil with a nutty aroma, characterized by comprising the following steps: S1: Remove the shells from the camellia seeds to obtain the kernels. After removing impurities, grind the kernels to 100 mesh. At 50℃, pH 5.2, and a rotation speed of 80 r / min, mix the compound enzyme solution and camellia seed powder at a mass ratio of 8:100 and perform enzymatic hydrolysis for 2 hours, stirring for 5 minutes every 30 minutes. The composition of the compound enzyme solution is cellulase: pectinase: water = 3:1:80. S2: After enzymatic hydrolysis, the tea seed powder is kept at 90℃ for 15 minutes to inactivate the enzyme. After cooling to 40℃, a 15% ethanol solution is sprayed into the enzymatic hydrolyzed tea seed powder at a mass ratio of 1:3. The mixture is stirred at a speed of 60 r / min while spraying. After spraying, double-layer microspheres are added. The amount of double-layer microspheres added is 8.5% of the mass of the enzymatic hydrolyzed tea seed powder. The mixture is continuously dispersed using an ultrasonic disperser for 15 minutes. The dispersed material is then allowed to stand at 35℃ for 25 minutes to form a mixed system. The method for preparing the bilayer microspheres is as follows: S21: Add a 1 mol / L hydrochloric acid solution to the maifan stone powder at a solid-liquid ratio of 1 g: 10 mL, stir in a water bath at 60 °C for 4 h, centrifuge and discard the supernatant, wash the solid repeatedly with deionized water until neutral, dry the washed solid at 105 °C for 6 h, and finally calcine at 350 °C for 2 h. S22: Dissolve β-cyclodextrin in deionized water at 60℃ at a solid-liquid ratio of 1g:10mL to prepare a β-cyclodextrin solution. Add the maifanite powder treated in S21 to the β-cyclodextrin solution at a solid-liquid ratio of 1:3, ultrasonically disperse for 10min, stir at 60r / min in a 45℃ water bath for 12h, and finally dry at 60℃ to obtain the composite powder. S23: The composite powder was dispersed in a 0.5% polyvinyl alcohol solution at a solid-liquid ratio of 1g:10mL, and sonicated for 5min to form a uniform suspension, which served as the inner aqueous phase; polylactic acid and talc were dissolved together in dichloromethane at a solid-liquid ratio of 2g:0.1g:20mL, and magnetically stirred at 35℃ until completely dissolved, which served as the oil phase; a 2% polyvinyl alcohol solution served as the outer aqueous phase. S24: The inner aqueous phase was slowly dripped into the oil phase at a volume ratio of 1:2 under high-speed shear at 10000 r / min, and emulsified under high-speed shear for 3 min to form a uniform primary emulsion. The primary emulsion was poured into the outer aqueous phase at a volume ratio of 1:10, stirred at 300 r / min, and emulsified at room temperature for 4 h. After emulsification, the mixture was allowed to stand for 30 min. The microsphere suspension was then transferred to a centrifuge tube and centrifuged at 3000 r / min for 5 min to collect the microsphere precipitate. The microsphere precipitate was resuspended and washed 3 times with deionized water. The washed microsphere suspension was freeze-dried for 24 h to obtain the bilayer microspheres.

[0027] S3: Add the mixture and 60% ethanol solution at a mass ratio of 3.5:1 into the vacuum extraction vessel, stir at 100 r / min for 5 min to mix evenly, raise the vacuum degree in the vessel to -0.08 MPa, maintain for 10 min, then raise the temperature to 50℃, and extract for 1.5 h in a pulse mode with ultrasonic power of 250W, 3s on, 2s off. S4: The extract was centrifuged at 5000 r / min for 15 min to separate the tea seed residue-microsphere mixture and the crude tea oil-ethanol mixture. The tea seed residue-microsphere mixture was dried at 50℃, and the double-layer microspheres were recovered after sieving. The crude tea oil-ethanol mixture was transferred to a vacuum deethanolating tank and deethanolated at 60℃ and -0.09 MPa for 20 min to obtain crude tea oil. S5: The recovered double-layer microspheres are placed in a vacuum desorption tank equipped with a condensation system and desorbed at 65℃ and -0.085MPa for 15 minutes to collect the aroma concentrate. The aroma concentrate is then added back to the crude tea oil at 45℃ and 100r / min. After stirring, the mixture is allowed to stand at 40℃ for 30 minutes. A 1% citric acid solution is added to the crude tea oil with added aroma, and the mixture is stirred at 45℃ for 20 minutes. The mixture is then centrifuged at 3000r / min for 15 minutes to remove the gum. The mixture is cooled to 38℃, and a decolorizing agent is added. After stirring for 25 minutes, the mixture is filtered. The decolorizing agent consists of activated clay and activated carbon in a ratio of 3:1. The amount of citric acid solution added is 1.2% of the crude tea oil, and the amount of decolorizing agent added is 1.2% of the crude tea oil. The decolorized tea oil is then transferred to a vacuum degassing tank and degassed at 65℃ and -0.09MPa for 20 minutes to obtain tea oil with a nutty aroma. Comparative Example 1

[0028] The difference between this comparative example and Example 4 is that the tea seed powder is not subjected to enzymatic hydrolysis with the compound enzyme solution; all other conditions are the same as in Example 4. Comparative Example 2

[0029] The difference between this comparative example and Example 4 is that the bilayer microspheres do not contain maifanite powder, while the other conditions are the same as in Example 4. Comparative Example 3

[0030] The difference between this comparative example and Example 4 is that the bilayer microspheres do not contain β-cyclodextrin, while the other conditions are the same as in Example 4. Comparative Example 4

[0031] The difference between this comparative example and Example 4 is that the enzymatically hydrolyzed tea seed powder does not contain double-layer microspheres, while the other conditions are the same as in Example 4. Comparative Example 5

[0032] The difference between this comparative example and Example 4 is that the tea seed powder is neither enzymatically hydrolyzed with the compound enzyme solution nor does it contain double-layer microspheres; all other conditions are the same as in Example 4.

[0033] The content of nut aroma components (tetramethylpyrazine and ethyl acetate) in the tea oil extracted in Examples 1-5 and Comparative Examples 1-5 was determined by headspace solid-phase microextraction-gas chromatography-mass spectrometry. The main operations are as follows: (1) Sample preparation: Take tea oil into a headspace bottle and seal it for later use; (2) Headspace adsorption: Place the headspace bottle in a constant temperature water bath for a certain period of time to equilibrate, insert the SPME fiber head to adsorb volatile aroma components, and remove the fiber head after adsorption is completed; (3) Desorption and injection: Insert the adsorbed fiber head into the GC injection port, desorb it at the set temperature for a certain period of time, and the aroma components enter the chromatographic column; (4) Chromatographic separation: Use the programmed temperature mode to separate different aroma components through the capillary chromatographic column; (5) Mass spectrometry detection: The separated components enter the mass spectrometer for ionization detection and obtain the mass spectrum; (6) Qualitative and quantitative analysis: Compare the mass spectrum with the standard spectral library for qualitative analysis, and calculate the content of the target aroma components by the external standard method. The results are shown in Table 1.

[0034] The extraction rate, color, unsaturated fatty acid content, and vitamin E content of the tea oil extracted in Examples 1-5 and Comparative Examples 1-5 were determined. The extraction rate was calculated as follows: (actual pure mass of extracted tea oil ÷ total mass of oil in the seed kernel) × 100%. The color and unsaturated fatty acid content were determined according to GB / T 11765-2018 "Camellia Seed Oil", and the vitamin E content was determined according to GB 5009.82-2016 "National Food Safety Standard - Determination of Vitamins A, D, and E in Food". The results are shown in Table 2.

[0035] Table 1. Content of Nut Aroma Components

[0036] As can be seen from Table 1, Examples 1-5 and Comparative Examples 1-2, due to their bilayer microspheres that specifically capture aroma components, have significantly higher contents of the core aroma components, tetramethylpyrazine and ethyl acetate, than Comparative Examples 3-5, and the extracted tea oil has a rich nutty aroma.

[0037] Table 2. Determination of Extraction Rate, Color, Unsaturated Fatty Acid Content, and Vitamin E Content

[0038] As shown in Table 2, the tea oils prepared using the embodiments of the present invention all have good color and high extraction rate. At the same time, the content of unsaturated fatty acids and vitamin E also proves that the method of the present invention can improve the extraction rate of tea oil and retain the aroma of nuts while fully preserving heat-sensitive nutrients, thus exhibiting good quality characteristics.

[0039] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing tea oil with a nutty aroma, characterized in that, Includes the following steps: S1: Remove the shells from the camellia seeds to obtain the kernels. After removing impurities, grind the kernels to 80-100 mesh. Mix the compound enzyme solution and camellia seed powder at 45-50℃, pH 4.8-5.2, and a rotation speed of 50-80 r / min for 2 hours, stirring for 5 minutes every 30 minutes. S2: After enzymatic hydrolysis, the tea seed powder is kept at 80-90℃ for 10-15 minutes to inactivate the enzyme. After cooling to 35-40℃, a 15% ethanol solution is sprayed into the enzymatically hydrolyzed tea seed powder while maintaining a mixing speed of 50-60 r / min. After spraying, double-layer microspheres are added and the mixture is continuously dispersed using an ultrasonic disperser for 10-15 minutes. The dispersed material is then allowed to stand at 35℃ for 20-25 minutes to form a mixed system. S3: Add the mixture and 60% ethanol solution to the vacuum extraction vessel, stir at 80-100 r / min for 5 min to mix evenly, raise the vacuum degree in the vessel to -0.07~-0.08 MPa, maintain for 8-10 min, then raise the temperature to 45-50℃, and extract for 1-1.5 h in a pulse mode with ultrasonic power of 250W, 3s on, 2s off; S4: The extract was centrifuged at 4000-5000 r / min for 15 min to separate the tea seed residue-microsphere mixture and the crude tea oil-ethanol mixture. The tea seed residue-microsphere mixture was dried at 45-50℃, and the double-layer microspheres were recovered after sieving. The crude tea oil-ethanol mixture was transferred to a vacuum deethanolating tank and deethanolated at 60℃ and -0.09 MPa for 20 min to obtain crude tea oil. S5: The recovered double-layer microspheres are placed in a vacuum desorption tank with a condensation system and desorbed at 65℃ and -0.085MPa for 12-15 minutes to collect the aroma concentrate. The aroma concentrate is then added back into the crude tea oil at 45℃ and 80-100r / min. After stirring, the mixture is allowed to stand at 40℃ for 30 minutes to undergo degumming, decolorization, and degassing, resulting in tea oil with a nutty aroma.

2. The method as described in claim 1, characterized in that, The composition of the complex enzyme solution in S1, calculated by mass ratio, is cellulase: pectinase: water = 3:1:

80.

3. The method as described in claim 1, characterized in that, The mass ratio of the compound enzyme solution to tea seed powder in S1 is (5-8):

100.

4. The method as described in claim 1, characterized in that, The mass ratio of the ethanol aqueous solution and the enzymatically hydrolyzed tea seed powder in S2 is 1:

3.

5. The method as described in claim 1, characterized in that, The amount of double-layered microspheres added in S2 is 7-8.5% of the mass of the enzymatically hydrolyzed tea seed powder.

6. The method as described in claim 1, characterized in that, The preparation method of the bilayer microspheres in S2 is as follows: S21: Add a 1 mol / L hydrochloric acid solution to the maifan stone powder at a solid-liquid ratio of 1 g: 10 mL, stir in a water bath at 60 °C for 4 h, centrifuge and discard the supernatant, wash the solid repeatedly with deionized water until neutral, dry the washed solid at 105 °C for 6 h, and finally calcine at 350 °C for 2 h. S22: Dissolve β-cyclodextrin in deionized water at 60℃ according to a solid-liquid ratio of 1g:10mL to prepare a β-cyclodextrin solution. Add the maifanite powder treated in S21 to the β-cyclodextrin solution at a solid-liquid ratio of 1:(2-3), ultrasonically disperse for 10min, stir at 60r / min in a 45℃ water bath for 12h, and finally dry at 60℃ to obtain the composite powder. S23: The composite powder was dispersed in a 0.5% polyvinyl alcohol solution at a solid-liquid ratio of 1g:10mL, and sonicated for 5min to form a uniform suspension, which served as the inner aqueous phase; polylactic acid and talc were dissolved together in dichloromethane at a solid-liquid ratio of 2g:0.1g:20mL, and magnetically stirred at 35℃ until completely dissolved, which served as the oil phase; a 2% polyvinyl alcohol solution served as the outer aqueous phase. S24: Slowly drip the inner aqueous phase into the oil phase under high-speed shear at 10000 r / min, and continue high-speed shear emulsification for 2-3 min to form a uniform primary emulsion; pour the primary emulsion into the outer aqueous phase, stir at 250-300 r / min, emulsify at room temperature for 3-4 h, let stand for 30 min after emulsification, transfer the microsphere suspension to a centrifuge tube, centrifuge at 3000 r / min for 5 min, and collect the microsphere precipitate; resuspend the microsphere precipitate with deionized water and wash 2-3 times, freeze-dry the washed microsphere suspension for 24 h to obtain the bilayer microspheres.

7. The method as described in claim 6, characterized in that, In S24, the volume ratio of the internal aqueous phase to the oil phase is 1:2, and the volume ratio of the primary emulsion to the external aqueous phase is 1:

10.

8. The method as described in claim 1, characterized in that, The mass ratio of the mixed system and the aqueous ethanol solution in S3 is (2.5-3.5):

1.

9. The method as described in claim 1, characterized in that, The specific treatment methods for degumming, decolorizing, and degassing in S5 are as follows: Add a 1% citric acid solution to the crude tea oil with added aroma, stir at 45℃ for 15-20 minutes, centrifuge at 3000 r / min for 10-15 minutes to remove the gum; cool to 38℃, add a decolorizing agent, stir for 20-25 minutes, filter, and transfer the decolorized tea oil to a vacuum degassing tank, degas at 65℃ and -0.09 MPa for 15-20 minutes. The composition of the decolorizing agent is activated clay: activated carbon = 3:1, the amount of citric acid solution added is 1-1.2% of the crude tea oil, and the amount of decolorizing agent added is 1.1-1.2% of the crude tea oil.

10. A tea oil with a nutty aroma prepared by the method as described in claims 1-9.

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