Preparation method and weight-losing application of coffee composition

Abstract

The invention provides a preparation method of a coffee composition and weight-losing application of the coffee composition, L-carnitine and resveratrol are subjected to microwave treatment, evaporation and drying treatment to obtain an L-carnitine and resveratrol eutectic solvent, the L-carnitine and resveratrol eutectic solvent is diluted with water to serve as an extracting agent to be mixed with coffee beans for coffee bean extraction, coffee condensation and coffee oil are obtained, and the weight-losing application of the coffee composition is achieved. And mixing the coffee gel, the coffee oil, the white kidney bean extract, the green tea extract and the like to form the coffee composition. By adopting the method, the polyphenol compounds and the coffee oil in the coffee beans can be rapidly and efficiently extracted, and the prepared coffee composition has good fat-reducing and weight-losing effects.

Description

Technical Field

[0001] The present invention relates to the technical field of composition preparation, and in particular to a preparation method of a coffee composition and its application in weight loss. Background Art

[0002] Coffee beans are the kernels inside the fruit of the coffee tree. They contain a variety of bioactive ingredients, such as alkaloids, phenolic acids, flavonoids, etc., which have antioxidant, lipid-lowering, blood sugar-lowering, and neuroprotective effects. Coffee drinks obtained by roasting, grinding, hot water extraction, and filtering coffee beans are simple to make and are popular in the market. However, this extraction process makes it difficult to fully utilize the efficacy of coffee beans and easily leads to waste of resources. Patent CN105899222A discloses a method for producing green coffee bean extract, which is to treat the green coffee bean raw material with supercritical carbon dioxide and then extract it with an organic solvent to obtain the green coffee bean extract. The green coffee bean extract contains 28%-37% 5-caffeoylquinic acid and 45%-60% total chlorogenic acid. It has pharmacological activities such as antioxidant, antiviral, anticancer, antibacterial, and fat-reducing activities. However, the extraction process requires the use of supercritical carbon dioxide extraction, which requires high equipment and is not conducive to controlling production costs. Summary of the Invention

[0003] The present invention aims to provide a method for preparing a coffee composition and its application for weight loss. The invention uses an aqueous solution diluted with a L-carnitine-resveratrol eutectic solvent as an extractant to extract coffee beans. This method not only simplifies the process and requires minimal equipment, but also provides an oral preparation prepared using the extract, coffee condensate and coffee oil, as raw materials, which exhibits excellent weight loss and lipid-lowering effects.

[0004] The present invention provides a method for preparing a coffee composition, comprising the following steps:

[0005] S1: adding L-carnitine and resveratrol in a molar ratio of 1:(0.25-6) to a solvent consisting of at least one of ultrapure water, methanol, ethanol, and acetonitrile to dissolve, and then subjecting the mixture to microwave treatment to obtain a first mixed solution; subjecting the first mixed solution to vacuum evaporation treatment until no distillate is evaporated to obtain a second mixed solution; and drying the second mixed solution to a constant weight to obtain a L-carnitine-resveratrol low eutectic solvent; wherein the L-carnitine-resveratrol low eutectic solvent is composed of L-carnitine molecules and resveratrol molecules, the carbonyl group in the L-carnitine molecule and the hydroxyl group in the resveratrol molecule have hydrogen bond interactions, and the distance between the carbonyl group in the L-carnitine molecule and the hydroxyl group in the resveratrol molecule is The L-carnitine-resveratrol deep eutectic solvent is diluted with water to obtain an extractant, wherein the concentration of the extractant is 2wt%-50wt%;

[0006] S2: mixing the extractant with coffee beans and performing steam distillation extraction, and separating by centrifugal filtration to obtain coffee condensate and coffee oil;

[0007] S3: Evenly mixing the coffee condensate, coffee oil, white kidney bean extract, green tea extract, vitamin B1, and vitamin B2 to obtain a coffee composition.

[0008] Deep Eutectic Solvents (DES) are a new type of green solvent formed by mixing a hydrogen bond acceptor (HBA) and a hydrogen bond donor (HBD) in a certain proportion. They are liquid at room temperature and have the advantages of low melting point, low volatility, good biodegradability, low cost, and environmental friendliness. L-carnitine is an amino acid that can promote the conversion of fat into energy, reduce fat accumulation, and has the effect of lowering serum total cholesterol and triglyceride levels; while resveratrol is a non-flavonoid polyphenol organic compound with anti-inflammatory, antioxidant and metabolic regulation effects, which can improve lipid metabolism, increase energy consumption, and promote fatty acid oxidation. The present invention uses an aqueous solution of a L-carnitine-resveratrol deep eutectic solvent as an extractant for coffee beans. On the one hand, the formation of a deep eutectic solvent by L-carnitine and resveratrol can improve the extraction efficiency of coffee beans. On the other hand, the performance characteristics of L-carnitine and resveratrol themselves can also enhance the efficacy of the coffee composition.

[0009] The main ingredient in white kidney bean extract is an α-amylase inhibitor, which can slow the digestion and absorption of starchy foods in the body, thereby helping to control blood sugar levels and manage weight. Green tea extract, a beneficial ingredient extracted from green tea, is rich in polyphenols and other active substances. It has anti-inflammatory, antioxidant, and blood sugar, blood pressure, and cholesterol-lowering effects. It can also aid weight loss by promoting fat burning and increasing metabolic rate.

[0010] During the synthesis of the L-carnitine-resveratrol deep eutectic solvent, the molar ratio of L-carnitine to resveratrol is 1:(0.25-6), preferably 1:(0.5-2). When the molar ratio is 1:1, the resulting L-carnitine-resveratrol deep eutectic solvent dilution has a high extraction efficiency. The synthesis of the L-carnitine-resveratrol deep eutectic solvent is preferably carried out in a protective gas atmosphere, which refers to an anti-oxidative protective atmosphere, such as an atmosphere formed by one or more inert gases such as helium, argon, nitrogen, and carbon dioxide.

[0011] In addition, in the present invention, "molar ratio" means "ratio of amounts of substances".

[0012] As a further improvement to the above scheme, the solvent used in the L-carnitine-resveratrol deep eutectic solvent synthesis reaction in step S1 is at least one of ultrapure water, methanol, ethanol, and acetonitrile. Ultrapure water is selected as the solvent in the synthesis system to ensure the formation of a deep eutectic solvent and to be environmentally friendly. The amount of solvent used is not particularly limited, as long as it can dissolve and mix the L-carnitine and resveratrol.

[0013] As a further improvement of the above scheme, the microwave treatment time in step S1 is preferably 30 min-6 h, the temperature is preferably 50° C.-80° C., the frequency is preferably 1 GHz-10 GHz, and the power is preferably 100 W-1500 W.

[0014] As a further improvement of the above solution, the concentration of the extractant in step S1 is 2 wt%-50 wt%, preferably 10 wt%-20 wt%.

[0015] As a further improvement of the above solution, in step S2, the coffee beans and the extractant are mixed at a solid-liquid ratio of 1 g:(5-50 mL).

[0016] As a further improvement of the above solution, the vacuum evaporation treatment temperature in step S1 is preferably 50° C.-90° C., and the pressure is preferably minus 0.04 MPa-minus 0.08 MPa.

[0017] As a further improvement of the above scheme, in step S3, the weight proportions of the components are: 20-70 parts of coffee condensate, 2-15 parts of coffee oil, 5-20 parts of white kidney bean extract, 2-10 parts of green tea extract, 1-3 parts of vitamin B1, and 1-3 parts of vitamin B2.

[0018] As a further improvement of the above solution, in step S3, the weight portion of the coffee condensate is 20-40 parts, and the weight portion of the coffee oil is 5-10 parts.

[0019] As a further improvement of the above solution, the method for preparing the coffee composition comprises the following steps:

[0020] S1: adding L-carnitine and resveratrol to ultrapure water at a molar ratio of 1:1 to dissolve the mixture, and reacting the mixture under microwave conditions of 50°C, 2.4 GHz, and 600 W for 4 h to obtain a first mixed solution; vacuum evaporating the first mixed solution under vacuum conditions of 60°C and -0.07 MPa until no distillate is evaporated to obtain a second mixed solution; and drying the second mixed solution at a constant temperature to a constant weight to obtain a L-carnitine-resveratrol deep eutectic solvent, and diluting the L-carnitine-resveratrol deep eutectic solvent with ultrapure water to obtain an extractant with a concentration of 10 wt%;

[0021] S2: Mixing the extractant with coffee beans at a solid-liquid ratio of 1 g:10 mL and performing steam distillation extraction. After the distillation, centrifugally filter the solid-liquid mixture in the reaction flask and the oily mixture in the condenser to obtain coffee condensate and coffee oil;

[0022] S3: 30 parts of the coffee condensate, 10 parts of the coffee oil, 6 parts of white kidney bean extract, 6 parts of green tea extract, 3 parts of vitamin B1, and 3 parts of vitamin B2 are mixed uniformly by weight to obtain a coffee composition.

[0023] As a further improvement of the above scheme, in step S1, after the L-carnitine and resveratrol are dissolved in the solvent, they are first stirred at room temperature for 3-10 hours and then subjected to microwave treatment.

[0024] As a further improvement of the above solution, in step S1, the second mixed solution is dried in a vacuum constant temperature drying oven, and the temperature cannot be too high, preferably between 50°C and 80°C.

[0025] As a further improvement to the above scheme, in step S2, the coffee beans are crushed, sieved and dried before being mixed with the extractant for steam distillation extraction. The drying temperature is 30° C.-60° C. and the drying time is 12 h-48 h.

[0026] As a further improvement of the above scheme, the temperature of the steam distillation extraction in step S2 is 50° C.-100° C., and the extraction time is 1 h-8 h.

[0027] As a further improvement of the above scheme, the centrifugal filtration separation treatment in step S2 is carried out according to conventional methods, preferably with a centrifugal speed of 5000 r / min-15000 r / min, a centrifugal time of 5 min-20 min, and preferably a 0.45 um organic phase filter membrane.

[0028] A coffee composition obtained by any one of the above preparation methods.

[0029] An application of the coffee composition obtained by any of the above preparation methods includes using the coffee composition as a raw material to prepare an oral preparation for lipid reduction and / or weight loss, wherein the oral preparation can be a food, a health product or a medicine.

[0030] As a further improvement of the above solution, the oral preparation is a microemulsion.

[0031] As a further improvement of the above scheme, the microemulsion includes a coffee composition and an emulsifier, a thickener, a preservative, a phospholipid compound and water; wherein the emulsifier is at least one of Tween 20, Tween 40, Span 20, Span 40, Span 80, polyglycerol fatty acid esters, sucrose esters, polyglycerol esters, monovalent soaps and divalent soaps; the thickener is at least one of guar gum, gelatin, carrageenan, xanthan gum, gum arabic, pectin and sodium carboxymethyl cellulose; the preservative is at least one of potassium sorbate, sodium benzoate, benzoic acid and monocaprylic glyceride; and the phospholipid compound is at least two of lecithin, cephalin, cardiolipin, soybean lecithin, egg yolk lecithin, phosphatidylserine, phosphatidylinositol and phosphatidylglycerol.

[0032] As a further improvement of the above scheme, the preparation method of the microemulsion is: heating and mixing the coffee composition with an emulsifier, a thickener, a preservative and water to obtain an oil phase; mixing the phospholipid compound evenly to obtain an oil phase, and adding the oil phase to the water phase for homogenization to obtain a microemulsion.

[0033] As a further improvement of the above scheme, the preparation method of the microemulsion is as follows: 30 parts of the coffee condensate, 10 parts of the coffee oil, 6 parts of white kidney bean extract, 6 parts of green tea extract, 3 parts of vitamin B1, and 3 parts of vitamin B2 are mixed uniformly by weight to obtain a coffee composition; then 0.5 parts of Tween 20, 0.5 parts of polyglycerol, 3 parts of guar gum, 2 parts of pectin, 1 part of potassium sorbate, and 27 parts of water are added to the coffee composition, heated, mixed, and stirred for 20-40 minutes to obtain an aqueous phase; 3 parts of egg yolk lecithin and 3 parts of phosphatidylserine are mixed uniformly to obtain an oil phase; and the oil phase is added to the aqueous phase and homogenized to obtain a microemulsion.

[0034] As a further improvement of the above scheme, the temperature of the heating and mixing is maintained by water bath heating so that the components in the aqueous phase are heated more evenly. The mixing process is accompanied by stirring at a rate of 100 r / min-1200 r / min; the homogenization treatment is carried out by stirring at a rate of 3000 rpm-15000 rpm and a stirring time of 5 min-30 min.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) L-carnitine and resveratrol are treated by microwave, distillation, and drying to form a deep eutectic solvent. Then, a water dilution of the deep eutectic solvent is used as an extractant, and the coffee beans are extracted by steam distillation in a one-step process. The entire process is simple to operate and does not require the use of complex and expensive equipment, making it suitable for low-cost large-scale production.

[0037] (2) Using a water-diluted solution of L-carnitine-resveratrol eutectic solvent as an extractant not only avoids the use of large amounts of organic solvents, but is also safe and environmentally friendly. Moreover, the extraction efficiency of this extraction process is much higher than that of water extraction, 10 wt% NaCl solution extraction, and enzymatic extraction, which can solve the pain point of poor extraction efficiency of traditional solvents and processes.

[0038] (3) The test results of total polyphenols and caffeic acid content in the coffee condensate extract and the results of quantum chemical calculations proved that the L-carnitine-resveratrol deep eutectic solvent has better specific recognition ability for caffeic acid during coffee bean extraction and can selectively extract caffeic acid;

[0039] (4) The coffee composition prepared by the present invention has a good antioxidant effect and can inhibit the accumulation of lipids in cells. At the same time, it can effectively slow down weight gain and reduce the levels of total triglycerides and total cholesterol in serum, and has the effect of lowering lipids and losing weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 These are quantum chemical characterization diagrams of the L-carnitine-resveratrol deep eutectic solvent prepared in Example 1 of the present invention, wherein (a) is a structural optimization diagram of the L-carnitine-resveratrol deep eutectic solvent, (b) is an ESP potential analysis diagram of the L-carnitine-resveratrol deep eutectic solvent, and (c) is an IRI analysis diagram of the L-carnitine-resveratrol deep eutectic solvent;

[0042] Figure 2 The quantum chemical characterization diagrams of L-carnitine-resveratrol and the active substance caffeic acid prepared in Example 1 of the present invention, wherein (a) is the structure optimization diagram, (b) is the ESP potential analysis diagram, and (c) is the IRI analysis diagram;

[0043] Figure 3 The cytotoxicity test results of the slimming microemulsion obtained in the present invention at different concentrations are shown;

[0044] Figure 4 The effect of the slimming microemulsion obtained by the present invention on lipid accumulation in damaged fat cells;

[0045] Figure 5 The present invention shows the effect of the slimming microemulsion obtained by the present invention on the body fat of obese rats. DETAILED DESCRIPTION

[0046] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0047] The weights of the relevant components mentioned in the examples of this application may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the examples of this application, it is within the scope disclosed in the examples of this application. Specifically, the mass described in the examples of this application may be a mass unit known in the chemical industry, such as μg, mg, g, kg, etc.

[0048] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0049] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0050] L-carnitine: 98% analytical grade, purchased from Liaoning Keshuo Nutrition Technology Co., Ltd.

[0051] Resveratrol: 99% analytical grade, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0052] Coffee beans were purchased from Yunnan Jinglan Tropical Crops Technology Co., Ltd.

[0053] White kidney bean extract was purchased from Xi'an Tianyi Biotechnology Co., Ltd.

[0054] Green tea extract was purchased from Shaanxi Yiruinong Biotechnology Co., Ltd.

[0055] Example 1

[0056] S1: In a nitrogen protective gas atmosphere, L-carnitine and resveratrol were added to ultrapure water at a molar ratio of 1:1 and dissolved, stirred at room temperature for 6 hours, and then reacted under microwave conditions at a temperature of 50°C, a frequency of 2.4 GHz, and a power of 600 W for 4 hours to obtain a first mixed solution of L-carnitine and resveratrol; under vacuum conditions of a temperature of 60°C and a pressure of -0.07 MPa, the first mixed solution was vacuum evaporated until no distillate was evaporated to obtain a second mixed solution; the second mixed solution was placed in a vacuum constant temperature drying oven at 50°C and dried at a constant temperature until the weight was constant to obtain a L-carnitine-resveratrol low eutectic solvent, and the L-carnitine-resveratrol low eutectic solvent was diluted with ultrapure water to obtain an extractant with a concentration of 10 wt%;

[0057] S2: The coffee beans are crushed through an 80-mesh sieve and dried in a constant temperature drying oven at 40°C for 24 hours to obtain coffee bean powder. The coffee bean powder is mixed with the extractant in step S1 at a solid-liquid ratio of 100g:1L and then subjected to steam distillation extraction for 6 hours. After the distillation, the solid-liquid mixture in the distillation flask and the first oily mixture in the condenser are centrifuged at a centrifugal speed of 10,000 r / min for 15 minutes. The supernatant of the solid-liquid mixture is filtered through a 0.45um organic phase filter membrane to separate the lower layer as coffee condensate L-1 and the upper layer as the second oily mixture. The upper oily liquid of the first oily mixture in the condenser is filtered through a 0.45um organic phase filter membrane to remove impurities and mixed with the second oily mixture to obtain coffee oil L-1, thereby completing the extraction of the coffee beans.

[0058] S3: Take 30 parts of coffee condensate L-1 and 10 parts of coffee oil L-1 obtained in step S2, and mix them evenly with 6 parts of white kidney bean extract, 6 parts of green tea extract, 3 parts of vitamin B1, and 3 parts of vitamin B2 by weight to obtain coffee composition L-1; then add 0.5 parts of Tween 20, 0.5 parts of polyglycerol, 3 parts of guar gum, 2 parts of pectin, 1 part of potassium sorbate and 27 parts of water, and mix and stir them in a water bath at a temperature of 50°C for 20 minutes to obtain an aqueous phase; 3 parts of egg yolk lecithin and 3 parts of phosphatidylserine are mixed evenly to obtain an oil phase; the oil phase is added to the aqueous phase and homogenized by stirring at a stirring rate of 10,000 rpm for 15 minutes to obtain a weight loss microemulsion L-1.

[0059] For example, Figure 1 These are the quantum chemical characterization diagrams of the L-carnitine-resveratrol deep eutectic solvent, where (a) is the structure optimization diagram, (b) is the ESP potential analysis diagram, and (c) is the IRI analysis diagram.

[0060] like Figure 1As shown in (a), the geometry optimization and frequency calculation of the L-carnitine-resveratrol eutectic solvent converged, and no imaginary frequency was found, indicating that the current structure is at the local minimum point of the potential energy surface and can exist stably. The hydroxyl group of resveratrol and the carbonyl group of L-carnitine have hydrogen bond interactions, and the distance between the hydroxyl group and the carbonyl group is Much shorter than the van der Waals radius.

[0061] As shown in Figure (1) (b), the formation mechanism of the L-carnitine-resveratrol deep eutectic solvent was qualitatively analyzed by ESP. The depth of color represents different electric potentials. For L-carnitine, the carbonyl region is electronegative, while a large area surrounding the nitrogen atom is electropositive. For resveratrol, the hydroxyl region is electropositive. After the formation of the deep eutectic solvent, the electronegative region of L-carnitine and the electropositive region of resveratrol attract each other, forming a stable deep eutectic solvent.

[0062] The interaction region indicator function (IRI) is used to characterize the van der Waals force, hydrogen bond, and steric repulsion of molecules, such as Figure 1 As shown in (c), different color blocks represent different intermolecular forces. The small discs within the ring structure represent steric hindrance. The stronger the steric hindrance, the less likely the atoms in the corresponding regions are to attract each other. The small discs outside the ring structure represent interactions that combine attraction and steric hindrance, or strong attraction, such as hydrogen bonds. The large, blocky transitional regions represent weak van der Waals interactions. The presence of large, blocky interaction regions between L-carnitine and resveratrol indicates the presence of van der Waals forces. Furthermore, the small discs between the hydroxyl and carbonyl groups strongly suggest the presence of strong hydrogen bonds between these two sites, based on existing research.

[0063] Example 2

[0064] The concentration of the extractant in step S1 was replaced with 5 wt %, and the remaining step parameters were the same as in Example 1 to obtain coffee condensate L-2 and coffee oil L-2.

[0065] Example 3

[0066] The concentration of the extractant in step S1 was replaced with 20 wt %, and the remaining step parameters were the same as in Example 1 to obtain coffee condensate L-3 and coffee oil L-3.

[0067] Example 4

[0068] The feed ratio of L-carnitine to resveratrol in step S1 was replaced with 2:1, and the remaining step parameters were the same as in Example 1 to obtain coffee condensate L-4 and coffee oil L-4.

[0069] Example 5

[0070] The feed ratio of L-carnitine to resveratrol in step S1 was replaced with 1:2, and the remaining step parameters were the same as in Example 1 to obtain coffee condensate L-5 and coffee oil L-5.

[0071] Example 6

[0072] The steam distillation time in step S2 was replaced with 2 h, and the remaining step parameters were the same as in Example 1 to obtain coffee condensate L-6 and coffee oil L-6.

[0073] Example 7

[0074] The steam distillation time in step S2 was replaced with 4 h, and the remaining step parameters were the same as in Example 1 to obtain coffee condensate L-7 and coffee oil L-7.

[0075] Example 8

[0076] The steam distillation time in step S2 was replaced with 8 h, and the remaining step parameters were the same as in Example 1 to obtain coffee condensate L-8 and coffee oil L-8.

[0077] Example 9

[0078] The steam distillation time in step S2 was replaced with 12 h, and the remaining step parameters were the same as in Example 1 to obtain coffee condensate L-9 and coffee oil L-9.

[0079] Example 10

[0080] In step S3, the weight parts of coffee condensate L-1 are replaced with 25 parts, and the weight parts of coffee oil L-1 are replaced with 15 parts. The remaining step parameters are the same as those in Example 1 to obtain a slimming microemulsion L-10.

[0081] Example 11

[0082] The weight parts of coffee condensate L-1 in step S3 were replaced with 35 parts, and the weight parts of coffee oil L-1 were replaced with 5 parts. The remaining step parameters were the same as those in Example 1 to obtain a slimming microemulsion L-11.

[0083] Comparative Example 1

[0084] L-carnitine and resveratrol were added to purified water at a molar ratio of 1:1 and stirred evenly to obtain a L-carnitine-resveratrol mixed solution with a total concentration of 10 wt %. The L-carnitine-resveratrol mixed solution was used as the extraction agent in step S2. The remaining step parameters were the same as those in Example 1 to obtain coffee gel D-1, coffee oil D-1, and weight loss microemulsion D-1.

[0085] Comparative Example 2

[0086] The extraction agent in step S2 was replaced with ultrapure water, and the remaining step parameters were the same as in Example 1 to obtain coffee condensate D-2 and coffee oil D-2.

[0087] Comparative Example 3

[0088] The extractant in step S2 was replaced with a 10 wt % NaCl aqueous solution, and the remaining step parameters were the same as in Example 1 to obtain coffee condensate D-3 and coffee oil D-3.

[0089] Comparative Example 4

[0090] In step S2, coffee bean powder was mixed with a 10 wt% aqueous solution of cellulase and then enzymatically hydrolyzed at 50°C for 1 hour. After the enzymatic hydrolysis, the aqueous solution of cellulase was used as an extractant. The remaining step parameters were the same as those in Example 1 to produce coffee condensate D-4, coffee oil D-4, and weight loss microemulsion D-4.

[0091] Comparative Example 5

[0092] Resveratrol in step S1 was replaced with propylene glycol, and the remaining step parameters were the same as in Example 1 to prepare coffee condensate D5 and coffee oil D5.

[0093] Comparative Example 6

[0094] Resveratrol in step S1 was replaced with 1,3-butanediol, and the remaining step parameters were the same as in Example 1 to prepare coffee condensate D6 and coffee oil D6.

[0095] Comparative Example 7

[0096] Resveratrol in step S1 was replaced with panthenol, and the remaining step parameters were the same as in Example 1 to prepare coffee gel D7 and coffee oil D7.

[0097] Comparative Example 8

[0098] Resveratrol in step S1 was replaced with glycolic acid, and the remaining step parameters were the same as in Example 1 to prepare coffee condensate D8 and coffee oil D8.

[0099] Test Example 1

[0100] 1. Test of total polyphenols and caffeic acid yield in coffee condensed water

[0101] The coffee condensates prepared in Examples 1-9 and Comparative Examples 1-8 were tested and calculated using the following method for the total polyphenol and caffeic acid yields obtained using different extraction processes.

[0102] (1) Total polyphenol yield test method

[0103] The polyphenols in coffee condensate were quantitatively analyzed using a UV-1900i series UV spectrophotometer at a wavelength of 765 nm.

[0104] Preparation of 10% Folin phenol reagent (freshly prepared): Pipette 10 mL of Folin phenol and dilute to 100 mL.

[0105] Preparation of 7.5% sodium carbonate solution: Weigh 37.50 g of sodium carbonate and dissolve it in water, then dilute to 500 mL.

[0106] Gallic acid standard stock solution (1 mg / mL, freshly prepared): Weigh 0.110 g of gallic acid monohydrate and dilute to 100 mL.

[0107] Gallic acid working solution: dilute the gallic acid standard stock solution into 0.01 mg / mL, 0.02 mg / mL, 0.03 mg / mL, 0.04 mg / mL and 0.05 mg / mL working solutions in sequence and prepare them before use.

[0108] 1 mL each of gallic acid working solution, water, and 100-fold diluted coffee condensate was placed in a graduated test tube. 5.0 mL of Folin's phenol reagent was added to each tube and shaken well. After reacting for 3-5 minutes, 4.0 mL of 7.5% sodium carbonate solution was added and shaken well. The mixture was allowed to stand at room temperature for 60 minutes to determine the total polyphenol concentration in the diluted coffee condensate. The actual total polyphenol concentration C1 in the coffee condensate after extraction was calculated based on the 100-fold dilution factor. The resveratrol concentration in the coffee condensate was C2. Based on the volume V of the extractant and the mass M of the coffee bean powder, the total polyphenol yield Y1 was calculated as (C1 - C2) * V / M × 100%.

[0109] (2) Caffeic acid yield test method

[0110] A Phenomenex Luna C18 column (4.6 mm × 250 mm, 5 μm) was selected, with a column temperature of 30°C, a flow rate of 1 mL / min, a detection wavelength of 285 nm, an injection volume of 10 μL, and mobile phases A and B: 0.5% formic acid in water. Gradient elution was performed using the elution program shown in Table 1. Accurately weigh 1.0 mg of caffeic acid standard into a 50 mL volumetric flask and dilute to volume with ultrapure water to prepare a caffeic acid standard stock solution (20 μg / mL). This caffeic acid standard stock solution was diluted with 50% methanol to obtain caffeic acid standard solutions with concentrations of 10.0, 5.0, 2.0, 1.0, and 0.2 μg / mL, respectively. The caffeic acid concentration of coffee condensate diluted 100-fold was measured, with the standard concentration plotted on the horizontal axis (X) and the peak area plotted on the vertical axis (Y). After obtaining the caffeic acid concentration in the diluted coffee condensate, the actual caffeic acid concentration C3 in the coffee condensate after extraction was calculated based on the dilution factor of 100. Based on the volume of the extractant V and the mass of the coffee bean powder M, the caffeic acid yield Y2 was calculated as C3*V / M×100%.

[0111] Table 1

[0112]

[0113] 2. Coffee oil yield test

[0114] The coffee oil obtained in Examples 1-9 and Comparative Examples 1-8 was used to calculate the coffee oil yields of different extraction processes.

[0115] Weigh the coffee oil and record it as M a , the mass of coffee bean powder is recorded as M, and the coffee oil yield Y3=M a / M×100%, each example or comparative example was extracted 3 times to ensure reliability and the average value was reported.

[0116] The test and calculation results of the total polyphenols, caffeic acid yield and coffee oil yield in the coffee condensate obtained by the extraction process of Examples 1-9 and Comparative Examples 1-8 are shown in Table 2.

[0117] Table 2

[0118] serial number <![CDATA[Total polyphenol yield Y1 / (mg / g)]]> <![CDATA[Yield of caffeic acid Y2 / (mg / g)]]> <![CDATA[Coffee oil yield Y3 / (mg / g)]]> Example 1 96.2 6.43 110.3 Example 2 84.5 6.04 104.4 Example 3 95.4 6.29 109.8 Example 4 96.0 6.40 109.2 Example 5 95.8 6.41 109.5 Example 6 67.5 4.35 80.9 Example 7 81.3 5.88 101.2 Example 8 97.7 6.40 112.5 Example 9 94.3 6.35 113.8 Comparative Example 1 88.7 6.11 99.5 Comparative Example 2 60.1 2.84 75.4 Comparative Example 3 73.7 3.10 88.3 Comparative Example 4 78.9 3.31 92.7 Comparative Example 5 86.4 6.09 98.5 Comparative Example 6 85.5 6.04 96.4 Comparative Example 7 81.2 4.33 90.7 Comparative Example 8 89.5 6.16 102.1

[0119] The results showed that with the increase of the extractant concentration of the L-carnitine-resveratrol deep eutectic solvent water dilution solution, the contents of total polyphenols, caffeic acid and coffee oil in the coffee bean extract first gradually increased and then stabilized or even decreased slightly. This is because as the extractant concentration increases, the degree of cell wall damage of the coffee beans increases, and more L-carnitine-resveratrol deep eutectic solvent interacts with the coffee beans. However, when the extractant concentration is too high, the system viscosity is large, which affects the mass transfer efficiency and makes it difficult to improve the extraction efficiency.

[0120] The test results of Example 1 and Comparative Example 1 show that the L-carnitine and resveratrol mixture also promotes coffee bean extraction, but the extraction efficiency of coffee beans is significantly enhanced after forming a deep eutectic solvent. This may be attributed to the fact that the intermolecular forces between L-carnitine and resveratrol, such as hydrogen bonds and van der Waals forces, are much stronger after forming a deep eutectic solvent than those in a physical blend. Therefore, it can more effectively destroy the cell walls of coffee beans, thereby effectively improving the extraction efficiency of coffee beans. This has positive significance for the in-depth development and utilization of plant resources.

[0121] From the test results of Example 1, Comparative Example 2, and Comparative Example 3, it can be found that by adding a 10wt% NaCl solution as an extractant on the basis of traditional steam distillation, the solubility of the active ingredients in the coffee beans in water can be increased, thereby improving the extraction efficiency, but it is still difficult to achieve the extraction effect of a deep eutectic solvent; and the enzymatic extraction process in Comparative Example 4 also achieves the purpose of improving the extraction efficiency by destroying the cellulose structure in the plant cell wall, causing more active ingredients to flow out. Comparing Example 1 with Comparative Examples 2-4, it can be seen that the selection of a water dilution of the L-carnitine-resveratrol deep eutectic solvent as the extractant for coffee beans has an extraction efficiency much higher than that of using water, 10wt% NaCl as an extractant, and enzymatic extraction, which can solve the pain point problem of poor extraction efficiency of the traditional extraction process.

[0122] It can be seen from Example 1 and Comparative Examples 5-8 that changing the composition of the deep eutectic solvent will affect the extraction efficiency. After replacing resveratrol with propylene glycol, 1,3-butylene glycol, panthenol or glycolic acid, although the extraction effect on coffee beans is better than water extraction, the extraction effect is best when the L-carnitine-resveratrol deep eutectic solvent diluent is used as the extraction agent.

[0123] By comparing the proportion of caffeic acid in total polyphenols in Examples 1-9 and Comparative Examples 1-4, it can be found that the proportion of caffeic acid in Examples 1-9 is relatively high, indicating that the L-carnitine-resveratrol deep eutectic solvent can selectively extract caffeic acid when extracting polyphenol compounds and has specific recognition ability for caffeic acid.

[0124] This paper investigates the possible mechanism of high extraction efficiency of polyphenolic compounds including caffeic acid in the L-carnitine-resveratrol deep eutectic solvent system through quantum chemical calculations. Using caffeic acid as a calculation model, the form and strength of the interaction between the L-carnitine-resveratrol deep eutectic solvent and caffeic acid were analyzed. The quantum chemical characterization results of the interaction between the L-carnitine-resveratrol deep eutectic solvent and caffeic acid are shown in Figure 2. Figure 2 As shown, (a) is the structure optimization diagram, (b) is the ESP potential analysis diagram, and (c) is the IRI analysis diagram.

[0125] The optimized structures of L-carnitine resveratrol deep eutectic solvent and caffeic acid are as follows Figure 2 As shown in (a), both the geometry optimization and frequency calculation converged, and no imaginary frequency was found, indicating that the current structure is at the local minimum of the potential energy surface and can exist stably. The distance between the carbonyl group of L-carnitine and the hydroxyl group of caffeic acid is much shorter than the van der Waals radius, which indicates that there is a hydrogen bond interaction between the L-carnitine resveratrol deep eutectic solvent and caffeic acid. Figure 2As shown in (b), the carbonyl regions of L-carnitine and caffeic acid are electronegative, while the hydroxyl groups are electronegative. When forming a stable structure, the electronegative regions of the L-carnitine-resveratrol deep eutectic solvent and the electronegative regions of caffeic acid attract each other, and the overall electrostatic potential is close to 0, thus forming a stable structure. The interaction region indicator function analysis of the L-carnitine-resveratrol deep eutectic solvent and caffeic acid is shown in Figure 2. Figure 2 As shown in (c), large, blocky regions of interaction exist between the L-carnitine-resveratrol deep eutectic solvent and caffeic acid, indicating the presence of van der Waals forces. Furthermore, small discs exist between the carbonyl groups in the L-carnitine-resveratrol deep eutectic solvent and the hydroxyl groups of caffeic acid. Existing research strongly suggests strong hydrogen bonding between these two sites, contributing to the formation and stability of the overall system. ESP, structural optimization, and IRI explain the higher yields of caffeic acid and total polyphenols in the L-carnitine-resveratrol deep eutectic solvent system.

[0126] Test Example 2

[0127] 1. DPPH free radical scavenging test

[0128] The weight loss microemulsions prepared in Example 1, Example 10, Example 11, Comparative Example 1, and Comparative Example 4 were subjected to DPPH free radical scavenging tests according to the following method:

[0129] Set up a sample tube (T), sample background (T0), DPPH tube (C) and solvent background (C0). For each sample tube (T) of the slimming microemulsion, three parallel tubes need to be set up, and different concentrations of slimming microemulsion solutions (0.0625 mg / mL, 0.125 mg / mL, 0.25 mg / mL, 0.5 mg / mL, 1 mg / mL) are respectively prepared. The dilution solvent of the slimming microemulsion is water.

[0130] For example, taking a 1 mg / mL slimming microemulsion solution as an example, the following sample tube (T), sample background (T0), DPPH tube (C) and solvent background (C0) are set:

[0131] Sample tube (T): 1 mL of slimming microemulsion solution (concentration of 1 mg / mL) + 2 mL of water + 1 mL of DPPH ethanol solution (concentration of 0.04 mg / mL);

[0132] Sample background tube (T0): 1 mL of slimming microemulsion solution (concentration 1 mg / mL) + 2 mL of water + 1 mL of 95 vol% ethanol solution;

[0133] DPPH tube (C): 3 mL of water + 1 mL of DPPH ethanol solution (concentration 0.04 mg / mL);

[0134] Solvent background tube (C0): 3 mL water + 1 mL 95% vol ethanol solution;

[0135] The solutions in the above reaction tubes were transferred into cuvettes, and the absorbance was measured at 517 nm. The DPPH radical scavenging rates of the different weight loss microemulsions were calculated using the following formula (I). The specific results are shown in Table 3.

[0136] Formula I:

[0137] Table 3

[0138]

[0139] As can be seen from Table 3, compared with the comparative example, the slimming microemulsion prepared in the example has a better scavenging effect on DPPH free radicals. With the increase of concentration, the DPPH scavenging rate gradually increases. In addition, the slimming microemulsion prepared in Example 1 of the present invention has a higher scavenging ability on DPPH free radicals than the slimming microemulsions prepared by other methods.

[0140] 2. Hydroxyl radical scavenging test

[0141] The slimming microemulsions prepared in Example 1, Example 10, Example 11, Comparative Example 1, and Comparative Example 4 were respectively mixed with water to prepare slimming microemulsion solutions, and hydroxyl radical scavenging tests were performed according to the following method:

[0142] Set up the sample tube (A 样品 ), loss pipe (A 损 ), undamaged (A 未损 ), three parallel tubes are required for each sample tube (T) of the slimming microemulsion, each of which is equipped with slimming microemulsion solutions of different concentrations (0.0625 mg / mL, 0.125 mg / mL, 0.25 mg / mL, 0.5 mg / mL, 1 mg / mL), and the solvent for diluting the slimming microemulsion solution is water.

[0143] A 样品 : 1 mL of o-phenanthroline ethanol solution (concentration of 5 mmol / L) + 2 mL of phosphate buffer (concentration of 0.2 mol / L) + 1 mL of weight loss microemulsion solution + 1 mL of ferrous sulfate solution (5 mmol / L) + 1 mL of H2O2 solution (concentration of 0.1% v / v);

[0144] A 损 : 1 mL of o-phenanthroline ethanol solution (concentration of 5 mmol / L) + 2 mL of phosphate buffer (concentration of 0.2 mol / L) + 1 mL of ultrapure water + 1 mL of ferrous sulfate solution (5 mmol / L) + 1 mL of H2O2 solution (concentration of 0.1% v / v);

[0145] A 未损 : 1 mL of o-phenanthroline ethanol solution (concentration of 5 mmol / L) + 2 mL of phosphate buffer (concentration of 0.2 mol / L) + 1 mL of ferrous sulfate solution (5 mmol / L) + 2 mL of ultrapure water.

[0146] The solutions in the above reaction tubes were transferred into cuvettes, and the absorbance was measured at 536 nm. The hydroxyl radical scavenging rates of the different weight loss microemulsions were calculated using the following formula II. The specific results are shown in Table 4.

[0147] Formula II:

[0148] Table 4

[0149]

[0150] The results show that compared with the comparative example, the weight-loss microemulsion prepared in the embodiment of the present invention has a better scavenging effect on hydroxyl radicals. With the increase of concentration, the hydroxyl radical scavenging rate gradually increases, and the weight-loss microemulsion prepared in Example 1 of the present invention has a higher scavenging ability on hydroxyl radicals than the weight-loss microemulsions prepared by other methods.

[0151] Test Example 3

[0152] The slimming microemulsions prepared in Example 1, Comparative Example 1, and Comparative Example 4 were subjected to in vitro cell culture to detect the effects of the slimming microemulsions on cell survival rate and fat metabolism.

[0153] 1. Experimental Methods

[0154] (1) Cell culture

[0155] HepG2 cells were cultured in Dulbecco's Modified Eagle's Medium (DMEM) containing 10% fetal bovine serum and 1% antibiotics in a 37°C incubator with 5% CO2. The medium was changed every three days. Cells were passaged using trypsinization when growth reached 90% or greater.

[0156] (2) Cytotoxicity assay

[0157] HepG2 cells were cultured at a rate of 8 × 10 3The cells were inoculated into a 96-well plate at a ratio of 100 cells / well and cultured in an incubator for 8 h to allow the cells to fully adhere to the wall. The culture medium in the 96-well plate was removed, and the plate was lightly washed once with PBS. The slimming microemulsions L-1, D-1, and D-4 obtained in Example 10, Comparative Example 5, and Comparative Example 6, and serum-free culture medium were added to make the slimming microemulsion concentrations reach 0, 0.0625 mg / mL, 0.125 mg / mL, 0.25 mg / mL, 0.5 mg / mL, and 1 mg / mL, and a control group was set with culture medium without slimming microemulsion. The 96-well plate was placed in an incubator again. One day later, the cell survival rate was detected by MTT assay, and the cell activity of the control group was set to 100%.

[0158] (3) Detection of triglycerides in cells

[0159] HepG2 cells were grown at 3×10 5 The cells were inoculated into 6-well plates at a concentration of 1.5 cells / well. After the cells adhered to the wall, they were treated with 1.8% ethanol and 0.5 mmol / L free fatty acids (FFA) for 24 hours. The injury model was established for 16 hours. The injury model group was set up. Then, weight loss microemulsion was added to the injured cells at a safe concentration. The weight loss microemulsion group was set up. The cells without injury treatment or drug administration before and after were set up as the control group. The culture was continued for 48 hours. The cells were collected and lysed by repeated freeze-thaw method. The intracellular triglyceride content was detected according to the instructions of the TG detection kit.

[0160] 2. Test results

[0161] (1) Effect of weight loss microemulsion on cell survival rate

[0162] The cytotoxicity test results of weight loss microemulsions L-1, D-1, and D-4 at different concentrations are as follows: Figure 3 The results show that the weight loss microemulsion obtained by the present invention has no obvious toxicity, and under the action of different concentrations, the activity of HepG2 cells is high, and the survival rate is greater than 85%.

[0163] (2) Effects of slimming microemulsion on lipid accumulation in damaged fat cells

[0164] After treating fat-damaged cells with 0.25 mg / mL slimming microemulsion L-1, slimming microemulsion D-1, and slimming microemulsion D-4 for 48 h, the intracellular TG content was determined using a TG detection kit. Figure 4 The results showed that compared with the model group, the intracellular TG content of cells treated with the slimming microemulsions was significantly reduced, among which the intracellular TG content of cells treated with slimming microemulsion L-1 decreased the most, indicating that the slimming microemulsion has a fat-reducing effect and can reduce fat accumulation in cells. The slimming microemulsion prepared with the coffee condensate and coffee oil obtained in Example 1 as raw materials has a better lipid-lowering effect.

[0165] Test Example 4

[0166] 1. Experimental Methods

[0167] (1) Rat culture

[0168] Fifty male SD rats, 8 weeks old, weighing 150-180 g each, were selected and fed for one week before the experiment. The rats were housed in a cage with 2-3 rats per cage; the temperature was 22±2°C, the humidity was 30-70%, and fluorescent lighting and darkness alternated every 12 hours; the rats had free access to food. The blank control group was fed a basal diet, while the remaining groups were fed a high-fat diet. The basal diet formula consisted of 55% nitrogen-free extract, 18% crude protein, 10% moisture, 8% crude ash, 5% crude fiber, and 4% crude fat; the calcium addition was 1.0%-2%, and the phosphorus addition was 0.6%-1.2%. The high-fat diet formula consisted of basal diet + 10% lard + 10% egg yolk powder. The animals and materials required for the experiment were obtained from the College of Animal Science and Technology, Hunan Agricultural University.

[0169] (2) Experimental animal grouping

[0170] The animals were acclimated for one week and randomly divided into two groups. One group, consisting of eight SD rats, served as the control group and were fed a basal diet. The remaining 42 rats were used to establish an obese rat model, which took approximately one month to establish. This group of rats was fed a high-fat diet. During this process, obesity-sensitive and obesity-resistant rats were screened and removed, resulting in 32 rats with an average weight greater than 20% higher than the control group. These rats were designated as obese rats for subsequent experiments. The experimental group consisted of a normal control (NC) group, a high-fat diet (HFD) group, and groups receiving slimming microemulsions L-1, D-1, and D-4. The NC group continued to be fed a basal diet with ad libitum access. The other groups were fed a high-fat diet, and the slimming microemulsions were administered via oral gavage. The dietary information of each group is shown in Table 5.

[0171] Table 5

[0172] Group diet Normal diet group (NC group) Basic feed High-fat diet group (HFD group) High-fat feed Slimming Microemulsion L-1 High-fat diet + 1g / kg / d weight loss microemulsion L-1 Slimming Microemulsion D-1 Group High-fat diet + 1g / kg / d weight loss microemulsion D-1 Slimming Microemulsion D-4 Group High-fat diet + 1g / kg / d weight loss microemulsion D-4

[0173] (3) Collection of serum and tissue samples

[0174] After the experiment, the rats were fasted for 12 hours and anesthetized with 3.5% chloral hydrate at a dose of 0.1 mL / 10 g of rat body weight. Blood samples were collected from the abdominal aorta. Serum was collected by centrifugation under low temperature conditions and stored at -80°C. The serum was not allowed to be repeatedly frozen and thawed. It can be aliquoted and stored for a long time. After the blood collection operation, the rats were quickly dissected, the portal duct system was ligated and cut, and the intact liver tissue was removed. The blood attached to the liver tissue was rinsed with saline, placed in a sterile culture dish, weighed, and stored at -80°C. The liver tissue was fixed in 4% paraformaldehyde.

[0175] (4) Body weight measurement

[0176] During the experiment, the animal morphology was observed, the rats were weighed weekly, and the initial body weight, weekly body weight, and body weight before sacrifice were recorded.

[0177] (5) Determination of serum biochemical indicators

[0178] The levels of triglyceride (TG) and total cholesterol (TC) in serum were determined using an automatic biochemical analyzer.

[0179] (6) Measurement of body fat

[0180] After the experiment, the rats were dissected, and perirenal and peritesticular fat were collected, weighed, and recorded. Peritoneal adipose tissue: The rat testicles were located in the lower abdomen. The white fat attached to them was located at a suitable location. Using surgical scissors, this fat was dissected along the vas deferens to the distal end of the testicles and then removed. Perirenal adipose tissue: The kidneys were located extraperitoneally on either side of the lumbar spine. The retroperitoneum was opened, and both kidneys were removed. The attached white fat was removed.

[0181] 2. Weight loss effect of slimming microemulsion on high-fat diet rats

[0182] (1) Effects of weight-loss microemulsion on the body weight of obese rats

[0183] The average weight of the experimental rats was over 20% higher than that of the control diet group, indicating successful obesity modeling. The weight changes of the rats in each group are shown in Table 6. The results showed that at the beginning of the experiment, the initial weights of the rats in the HFD group, the slimming microemulsion L-1 group, the slimming microemulsion D-1 group, and the slimming microemulsion D-4 group were similar, with only the rats in the NC group weighing less. Throughout the treatment process, the weight of the rats in each group showed an overall upward trend. After four weeks of the experiment, the rats receiving the slimming microemulsion showed a more significant weight loss than the HFD group, with the slimming microemulsion L-1 group showing the greatest weight loss.

[0184] Table 6

[0185] Group Week 0 Week 1 Week 2 Week 3 Week 4 NC group 452.45g 485.74g 504.11g 511.62g 516.78g HFD group 558.34g 603.4g 647.20g 675.15g 693.27g Slimming Microemulsion L-1 554.51g 572.38g 588.52g 602.14g 608.75g Slimming Microemulsion D-1 Group 557.92g 579.40g 600.64g 612.37g 621.21g Slimming Microemulsion D-4 Group 560.34g 589.74g 612.51g 625.46g 630.57g

[0186] (2) Effects of slimming microemulsion on serum parameters of obese rats

[0187] After the experiment, serum triglyceride (TG) and total cholesterol (TC) levels were measured in each group of rats, and the average values are reported in Table 7. The results showed that the NC group had lower TG levels than all other groups. Compared with the HFD group, the TG levels of rats in the slimming microemulsion L-1, slimming microemulsion D-1, and slimming microemulsion D-4 groups were significantly lower, indicating that the slimming microemulsion can reduce serum TG levels. The total cholesterol levels of rats in the HFD group were significantly higher than those in all other groups. The total cholesterol levels of rats in the slimming microemulsion L-1, D-1, and D-4 groups were similar to those in the NC group, indicating that the slimming microemulsion can restore total cholesterol levels in obese rats to normal levels, with the slimming microemulsion L-1 group showing the greatest recovery effect.

[0188] Table 7

[0189] Group TG content (mmol / L) TC content (mmol / L) NC group 0.78 1.62 HFD group 1.67 2.57 Slimming Microemulsion L-1 1.05 1.63 Slimming Microemulsion D-1 Group 1.13 1.65 Slimming Microemulsion D-4 Group 1.25 1.71

[0190] (3) Effects of slimming microemulsion on body fat in obese rats

[0191] The rats in each group were dissected, and the perirenal fat and peritesticular fat were removed and weighed. The ratio of fat to body weight was calculated and the average value was reported. Figure 5 The results showed that the fat / body ratio of rats in the HFD group was the highest among all groups. The fat / body ratio of rats in the slimming microemulsion L-1 group was close to that of the NC group. The fat / body ratio of rats in the slimming microemulsion D-1 and slimming microemulsion D-4 groups was still relatively high, indicating that slimming microemulsion L-1 can effectively reduce the increase in fat / body ratio caused by a high-fat diet.

[0192] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for preparing a coffee composition, characterized in that: The following steps are involved: S1: adding L-carnitine and resveratrol in a molar ratio of 1:(0.25-6) to a solvent consisting of at least one of ultrapure water, methanol, ethanol, and acetonitrile, dissolving the mixture and subjecting the mixture to microwave treatment to obtain a first mixed solution; subjecting the first mixed solution to vacuum evaporation until no distillate is evaporated to obtain a second mixed solution; drying the second mixed solution to a constant weight to obtain a L-carnitine-resveratrol low eutectic solvent; wherein the L-carnitine-resveratrol low eutectic solvent is composed of L-carnitine molecules and resveratrol molecules, the carbonyl group in the L-carnitine molecule and the hydroxyl group in the resveratrol molecule having a hydrogen bond interaction, and the distance between the carbonyl group in the L-carnitine molecule and the hydroxyl group in the resveratrol molecule is 1.0Å-2.2Å; diluting the L-carnitine-resveratrol low eutectic solvent with water to obtain an extractant, wherein the concentration of the extractant is 2wt%-50wt%; S2: mixing the extractant with coffee beans and performing steam distillation extraction, and separating by centrifugal filtration to obtain coffee condensate and coffee oil; S3: Evenly mixing the coffee condensate, the coffee oil, the white kidney bean extract, the green tea extract, vitamin B1, and vitamin B2 to obtain a coffee composition.

2. The method for preparing the coffee composition according to claim 1, wherein: In step S1, the molar ratio of L-carnitine to resveratrol is 1:(0.5-2).

3. The method for preparing the coffee composition according to claim 1, wherein: In step S1, the microwave treatment time is 30 min-6 h, the temperature is 50° C.-80° C., the frequency is 1 GHz-10 GHz, and the power is 100 W-1500 W.

4. The method for preparing the coffee composition according to claim 1, wherein: The concentration of the extractant in step S1 is 10 wt % to 20 wt %.

5. The method for preparing the coffee composition according to claim 1, wherein: In step S2, the extractant and coffee beans are mixed at a solid-liquid ratio of 1 g:(5-50 mL).

6. The method for preparing the coffee composition according to claim 1, wherein: The weight proportions of the components in step S3 are: 20-70 parts of coffee condensate, 2-15 parts of coffee oil, 5-20 parts of white kidney bean extract, 2-10 parts of green tea extract, 1-3 parts of vitamin B1, and 1-3 parts of vitamin B2.

7. The method for preparing the coffee composition according to any one of claims 1 to 6, wherein: The following steps are involved: S1: adding L-carnitine and resveratrol to ultrapure water at a molar ratio of 1:1 to dissolve the mixture, and reacting the mixture under microwave conditions of 50°C, 2.4 GHz, and 600 W for 4 h to obtain a first mixed solution; vacuum evaporating the first mixed solution under vacuum conditions of 60°C and -0.07 MPa until no distillate is evaporated to obtain a second mixed solution; and drying the second mixed solution at a constant temperature to a constant weight to obtain a L-carnitine-resveratrol deep eutectic solvent, and diluting the L-carnitine-resveratrol deep eutectic solvent with ultrapure water to obtain an extractant with a concentration of 10 wt%; S2: Mixing the extractant with coffee beans at a solid-liquid ratio of 1 g:10 mL and performing steam distillation extraction. After the distillation, centrifugally filter the solid-liquid mixture in the reaction flask and the oily mixture in the condenser to obtain coffee condensate and coffee oil; S3: 30 parts of the coffee condensate, 10 parts of the coffee oil, 6 parts of white kidney bean extract, 6 parts of green tea extract, 3 parts of vitamin B1, and 3 parts of vitamin B2 are mixed uniformly by weight to obtain a coffee composition.

8. A coffee composition obtained by the preparation method according to any one of claims 1 to 7.

9. An application of the coffee composition according to claim 8, characterized in that: The invention comprises using the coffee composition as a raw material to prepare an oral preparation for weight loss.

10. The use of the coffee composition according to claim 9, characterized in that: The oral preparation is a microemulsion.

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