Analysis method for simulating oral cavity and oral cavity fragrance release durability of ester compounds in baijiu and application of ester compounds

Abstract

The invention belongs to the technical field of baijiu detection, and relates to a simulated oral cavity, an analysis method for the oral cavity fragrance release durability of ester compounds in baijiu and application of the ester compounds, the simulated oral cavity comprises a cavity, the cavity is provided with a cover body, the cover body comprises a cover body and channels, and the channels comprise a gas inlet channel, a gas outlet channel, a sample adding channel and a sampling channel; the gas inlet channel and the gas outlet channel are oppositely arranged on the cover body, the sampling channel is arranged in the center of the cover body, in a working state, the gas inlet channel and the gas outlet channel are inserted into the cavity, and the lower edge of the gas inlet channel is arranged at the position 1-2 cm above materials; the lower edge of the air outlet channel is arranged at the position 1-2 cm away from the lower edge of the cover body, and the stirrer is arranged in the cavity. The simulated oral cavity can truly restore the dynamic change of the Baijiu in the oral cavity, is suitable for analyzing the fragrance release durability of ester compounds in the Baijiu so as to obtain compounds with strong fragrance release durability, and has an important value for Baijiu production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of liquor detection, and particularly relates to a method for analyzing the oral aroma release persistence of ester compounds in liquor simulation and application of ester compounds. BACKGROUND

[0002] Liquor, as the national liquor of China, is a traditional alcoholic beverage enjoying worldwide reputation and being deeply loved by consumers. Flavor is the core feature of liquor and is also a key factor determining the quality and consumer preference. Aroma compounds are released from the matrix to the nasal cavity to stimulate olfactory receptors, involving two perception pathways, i.e. anterior and posterior nasal pathways, of which the posterior nasal perception pathway is the most complex.

[0003] It is well known that the posterior nasal aroma perception occurring during food consumption or drinking is the key to forming the final flavor characteristics and plays an important role in consumer preference. The volatile release of flavor substances in the real oral cavity is affected by multiple factors and has the characteristics of dynamic change and low concentration. Therefore, for the analysis of flavor substances in the oral or nasal cavity, a simulation system is needed to maximize the control of influencing factors so as to evaluate the oral aroma release characteristics of aroma compounds from the perspective of analyzing compounds.

[0004] There are numerous flavor substances in liquor, including esters, alcohols, aldehydes, ketones, acids, etc. Among the numerous flavor substances in liquor, ester compounds are one of the most important components, which not only play an important role in the flavor performance of liquor, but also have a wide variety, high content and typical fruity characteristics, and are one of the important aroma characteristics perceived by consumers during tasting. However, although the aroma characteristics of ester compounds are obvious at the initial entry, this aroma often decays rapidly after drinking and is not persistent. Therefore, analyzing the oral aroma release persistence of different ester compounds and then finding ester compounds with more persistent aroma release has very important theoretical guiding significance for improving the overall sensory experience of liquor, especially in the application of fruity flavor blending. SUMMARY

[0005] In one aspect, the present application provides a simulated oral cavity, which comprises a working state and comprises:

[0006] a cavity configured to store materials;

[0007] The cavity is equipped with a cover, and the cover comprises a cover body and a channel, and the channel comprises an air inlet channel, an air outlet channel, a sample addition channel and a sample collection channel.

[0008] The air inlet channel and the air outlet channel are oppositely arranged on the cover body, the sampling channel is arranged at the center of the cover body, in the working state, the air inlet channel and the air outlet channel are inserted into the cavity, the lower edge of the air inlet channel is arranged at a position 1cm-2cm above the material, and the lower edge of the air outlet channel is arranged at a position 1cm-2cm away from the lower edge of the cover body,

[0009] The stirrer is arranged inside the cavity.

[0010] In some specific embodiments, in the working state, the simulated oral cavity comprises a temperature control device configured to control the temperature of the material stored in the cavity, and the channel further comprises a temperature measuring channel.

[0011] In some specific embodiments, the temperature measuring channel is oppositely arranged with the sample adding channel.

[0012] In some specific embodiments, the sampling channel is arranged at the center of the cover body.

[0013] In some specific embodiments, the cavity is a 100mL screw glass pool body, the cover body is a hole polytetrafluoroethylene cover, and the cover body is detachably arranged on the cavity,

[0014] In some specific embodiments, in the working state, a thermometer is arranged on the temperature measuring channel, and in some specific embodiments, the range of the thermometer is 0℃-50℃, and the thermometer is used to monitor the temperature of the material in the pool body in real time.

[0015] In some specific embodiments, a thermometer is installed at the top of the cavity, the thermometer is a mercury thermometer, the thermometer is inserted into the inside of the pool body from above the cover body through the temperature measuring channel and contacts the liquid in the simulated oral cavity,

[0016] In some specific embodiments, the stirrer comprises a magnetic rotor, and the outside of the cavity is further provided with a magnetic stirrer body for rotating the magnetic rotor; the temperature control device is a constant temperature water bath.

[0017] In some specific embodiments, the simulated oral cavity further comprises a beaker, the beaker is located outside the cavity, the cavity is placed in the beaker, the beaker is a double-layer water bath jacketed beaker, the outer capacity of the double-layer water bath jacketed beaker is 500mL, the double-layer water bath jacketed beaker has a water inlet and a water outlet, the water inlet is arranged at the upper part of one side of the double-layer water bath jacketed beaker, the water outlet is arranged at the opposite side of the water outlet side of the double-layer water bath jacketed beaker, the water inlet is connected to the water bath through a pipeline, the water bath provides hot water to the double-layer water bath jacketed beaker through the pipeline and the water inlet, the hot water returns to the water bath through the water outlet to form a water bath circulation, the water bath circulation is driven by a submersible pump, and the submersible pump is a micro submersible pump.

[0018] In some embodiments, the channel is a silica gel hose pipe, the water bath is a constant temperature water bath, and the constant temperature water bath is set at a temperature of 40°C, which can effectively ensure that the temperature of the material in the cavity is maintained at 37°C, thereby achieving simulation of the human body temperature.

[0019] In some embodiments, the air inlet channel and the air outlet channel are oppositely distributed, and the diameter is 8 mm. In addition, the air inlet channel is inserted into the cavity and arranged at a position 1-2 cm above the liquid surface, and the air outlet channel is inserted into the cavity and arranged at a position 1-2 cm below the lower edge of the cover body, so as to ensure that the gas is introduced from above the liquid surface and avoid direct escape of the gas, thereby enhancing the flow path and mixing efficiency of the gas in the cavity.

[0020] In some embodiments, the sampling channel and the temperature measuring channel are oppositely distributed, and the diameter is 6 mm.

[0021] In some embodiments, the sampling channel is located at a central position relative to the air inlet channel, the air outlet channel, the sample adding channel, and the temperature measuring channel, and the diameter is 3 mm. The sampling channel and the air inlet channel, the air outlet channel, the sample adding channel, and the temperature measuring channel are kept at a distance of 1.5 cm. The lower edge of the sampling channel is located in the middle of the air part of the cavity, and the sampling channel is arranged on the cover body through a sealing ring to avoid gas leakage during the plugging process of the sampling channel. The lower edge of the sampling channel is configured to collect the "average gas state" formed by the volatile substances in the air after the liquid in the cavity is mixed.

[0022] In some embodiments, a carrier gas is introduced into the air inlet channel. In some embodiments, the carrier gas is nitrogen, and the nitrogen is high-purity nitrogen with a purity of ≥99.999%. The flow rate of the carrier gas is 150 mL / min, and the flow rate is controlled by a gas flow meter.

[0023] In some embodiments, the air inlet channel and the air outlet channel are both polytetrafluoroethylene pipes, which form a stable flow path for the gas in the pool body. The above design can effectively reduce the risk of oxidative degradation and secondary adsorption of aroma components, and more truly reproduce the release dynamic process of aroma substances in the actual oral environment.

[0024] The second aspect of the present application provides an analysis method for the oral aroma release durability of ester compounds in liquor. The method is based on the simulation of the oral cavity in the first aspect to analyze the oral aroma release durability of ester compounds in liquor, and includes the following steps:

[0025] I. Fill the carrier gas into the cavity of the simulated oral cavity, add liquor and artificial saliva, and mix well;

[0026] II. Sampling and analyzing the volatile gas after mixing the liquor and the artificial saliva, wherein the sampling and analyzing comprises independent sampling and analyzing at multiple time points;

[0027] III. Determining the oral aroma release durability of the ester compounds in the liquor at different time points by comparing the ratio of the peak area of the ester compounds obtained at different time points to the peak area at the initial time.

[0028] In some embodiments, the ester compound is an ester compound with an odor activity value ≥ 50.

[0029] In some embodiments, the ester compound with an odor activity value ≥ 50 includes 3-methyl butyric acid ethyl ester, 2-methyl butyric acid ethyl ester, butyric acid ethyl ester, hexanoic acid ethyl ester, 2-methyl propionic acid ethyl ester, 4-methyl pentanoic acid ethyl ester, and valeric acid ethyl ester.

[0030] In some embodiments, the screening method of the ester compound with an odor activity value ≥ 50 comprises the following steps:

[0031] S1: Direct injection combined with gas chromatography-hydrogen flame ionization detector is used to analyze the high content ester compound content in the liquor.

[0032] S2: Headspace-solid phase microextraction combined with comprehensive two-dimensional gas chromatography-mass spectrometry is used to analyze the low content ester compound content.

[0033] S3: The odor activity value is calculated according to the obtained high content ester compound content, low content ester compound content, and odor threshold, and the ester compound with an odor activity value ≥ 50 is selected as the target ester compound.

[0034] In some embodiments, the direct injection condition includes: taking 1 mL of the liquor sample into a 2 mL chromatographic injection bottle, adding 50 μL of n-pentyl acetate (125.50 mg / L) as an internal standard, mixing uniformly, and then taking 1 μL for direct injection.

[0035] In some embodiments, the gas chromatography condition in S1 includes: initial temperature 35℃, maintaining running for 5 min; then increasing the temperature from 35℃ to 100℃ at a rate of 4℃ / min, maintaining running for 2 min; then increasing the temperature from 100℃ to 150℃ at a rate of 8℃ / min; finally increasing the temperature from 150℃ to 200℃ at a rate of 15℃ / min, maintaining running for 25 min. The carrier gas is helium with a purity greater than 99.999%, the flow rate is 1 mL / min, the split mode injection is used, and the ratio is 20:1.

[0036] In some embodiments, the headspace-solid phase microextraction pre-treatment conditions in S2 include: 5 mL of diluted liquor sample with alcohol content of 5% vol is placed in a 20 mL headspace bottle, 1.5 g of NaCl and 20 μL of acetic acid-2-phenylethyl ester-d3 (174.91 μg / L) are added, the pre-treatment sample is incubated at 45°C for 5 min, and then extracted at 400 rpm for 45 min. After extraction, immediately desorb at the injection port at 250°C for 5 min.

[0037] In some embodiments, the two-dimensional gas chromatography conditions in S2 include: the gas chromatography is Agilent 7890B (Agilent, USA) equipped with two serial chromatographic columns, wherein the first dimension chromatographic column is DB-FFAP capillary column (60 m x 0.25 mm x 0.25 μm, Agilent, USA), and the second dimension chromatographic column is Rxi-17Sil capillary column (1.5 m x 0.25 mm x 0.25 μm, Restek, USA); the column oven initial temperature is 45°C, maintained for 3 min; then increased from 45°C to 150°C at a rate of 4°C / min, maintained for 2 min; then increased from 150°C to 200°C at a rate of 6°C / min; finally increased from 200°C to 230°C at a rate of 10°C / min, maintained for 10 min. The carrier gas is helium with purity greater than 99.999%, the flow rate is 1 mL / min, and the sample is injected in splitless mode.

[0038] In some embodiments, the mass spectrometry conditions in S2 include: the detector and transmission line temperature are set to 230°C and 240°C respectively, the ion source voltage is 70 eV, the ion scanning range is 35-400 amu, and the scanning frequency is 100 spestra / s.

[0039] In some embodiments, in step two, the sampling analysis is extraction analysis, and the extraction time is 1.8 min-2.2 min.

[0040] In some embodiments, in step two, the multi-time point independent sampling analysis includes: sampling and analyzing the volatile gases obtained after the liquor and artificial saliva are mixed and then respectively interval 0 s, 30 s, 60 s, 120 s and 150 s.

[0041] In some embodiments, in step two, the extraction analysis includes: the hand-held solid phase microextraction sampler is adsorbed through the sampling channel for extraction, and the ester compounds in the extracted compounds are analyzed by two-dimensional gas chromatography-time of flight mass spectrometry.

[0042] In some specific embodiments, the analysis method analyzes the obtained ester compounds with aroma release persistence in the liquor, including at least one of 2-methyl butyric acid ethyl ester, butyric acid ethyl ester, 3-methyl butyric acid ethyl ester and valeric acid ethyl ester.

[0043] The third aspect of the present application provides an application of ester compounds in the field of liquor, wherein the ester compounds include at least one of 2-methyl butyric acid ethyl ester, butyric acid ethyl ester, 3-methyl butyric acid ethyl ester and valeric acid ethyl ester.

[0044] In some specific embodiments, the ester compounds include 2-methyl butyric acid ethyl ester, butyric acid ethyl ester, 3-methyl butyric acid ethyl ester and valeric acid ethyl ester.

[0045] Compared with the prior art, the present application has the following beneficial effects:

[0046] The present application simulates the changes of liquor in the human oral cavity by constructing a simulated oral cavity, simulates the oral chewing by a stirrer, sets the relative positions of the air inlet and air outlet channels in the cavity, so that the gas flow direction is controllable, which is helpful to simulate the volatilization, diffusion and odor molecule rising movement of liquor in the oral cavity due to breathing, and by adjusting the lower edge positions of the air inlet and air outlet channels, on the one hand, the gas in the cavity is fully mixed, and on the other hand, the direct escape of the gas is avoided, the design of the sample adding channel and the sample channel facilitates the addition of liquor samples and the extraction of intermediate products without damaging the overall environment, thereby improving the operation convenience and repeatability of the experiment; the simulated oral cavity of the present application is provided with a cover, has airtightness, can avoid material overflow and odor volatilization, and ensures the accuracy of the experimental results; the simulated oral cavity of the present application can support quantitative and qualitative analysis of liquor, can cooperate with instruments such as GC-MS, electronic nose and electronic tongue to detect the dynamic changes of flavor substances, can be used for studying the aroma release rules, taste changes, alcohol stimulation and other multi-dimensional sensory characteristics of liquor, and can support the establishment of a more systematic liquor evaluation model; compared with the traditional manual evaluation method, the device can complete multiple repeated experiments under small volume conditions, effectively reduces the consumption of liquor samples, and meets the green scientific research concept; the simulated oral cavity of the present application can more truly restore the dynamic changes of liquor in the oral cavity, and analyze the aroma release persistence of ester compounds in liquor through the simulated oral cavity, and through the method, ester compounds with strong aroma release persistence in liquor can be analyzed, which have important value and significance for liquor production. BRIEF DESCRIPTION OF DRAWINGS

[0047] The provided drawings can further understand the present application, and constitute a part of the specification, together with the embodiments of the present application, for explaining the present application, and do not constitute a limitation on the present application.

[0048] Figure 1This is the simulated oral cavity device used in this application for evaluating the persistence of ester aroma release in baijiu (Chinese liquor);

[0049] Figure 2 This is a plot showing the total aroma release area of ​​the target ester compounds in Comparative Example 1;

[0050] Figure 3 This is a plot showing the total aroma release area of ​​the target ester compounds in Comparative Example 2;

[0051] Figure 4 This is a comparison chart of the oral aroma release persistence of the target ester compounds at different time points in Example 2. Detailed Implementation

[0052] To better illustrate the purpose, technical solutions, and advantages of this application, the following embodiments further illustrate the specific implementation methods of the technical solutions of this application. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0053] Experimental materials:

[0054] Sample: 53% vol Maotai-flavor liquor, sourced from a Maotai-flavor liquor distillery in Guizhou.

[0055] Equipment: Extraction head (2cm, 50 / 30μm, DVB / CAR / PDMS, Chromatography Department, USA); Fully two-dimensional gas chromatography-time-of-flight mass spectrometry (GC-TOF-MS) 4D (LECO, USA); the first-dimensional column was a DB-FFAP capillary column (60m×0.25mm×0.25μm, Agilent, USA), and the second-dimensional column was an Rxi-17Sil capillary column (1.5m×0.25mm×0.25μm, Restec, USA).

[0056] Artificial saliva parameters: Add 0.877g NaCl, 0.477g KCl, 5.028g NaHCO3, 1.369g K2HPO4·3H2O, 0.441g CaCl2·2H2O, 2.16g mucin (type 1-S, from bovine submandibular gland), and α-amylase (200,000U) to 1L of ultrapure water. Store the prepared saliva sample at 4℃ for later use.

[0057] Unless otherwise specified, all other raw materials used in the embodiments and comparative examples of this application can be obtained commercially.

[0058] Example 1: A simulated oral cavity

[0059] The embodiment provides a simulated oral cavity, which comprises a working state, and the simulated oral cavity specifically comprises Figure 1

[0060] a cavity 1 configured to store materials;

[0061] The cavity is provided with a cover 2, and the cover comprises a cover body and channels, wherein the channels comprise an air inlet channel 3, an air outlet channel 4, a sample adding channel 10, a temperature measuring channel 8 and a sampling channel 5.

[0062] The air inlet channel 3 and the air outlet channel 4 are oppositely arranged on the cover body, the extraction channel 5 is arranged at the center of the cover body, and the air inlet channel 3 is arranged above the materials at a position of 1-2 cm from the materials.

[0063] A stirrer is arranged inside the cavity 1.

[0064] A temperature control device is configured to control the temperature of the materials stored in the cavity.

[0065] Specifically, in the embodiment, the stirrer comprises a magnetic rotor 6, and when the stirrer is the magnetic rotor 6, a magnetic stirrer body 9 for rotating the magnetic rotor is further arranged outside the cavity 1.

[0066] Specifically, in the embodiment, the temperature control device is a constant temperature water bath 11.

[0067] Specifically, in the embodiment, a thermometer 7 is arranged in the temperature measuring channel 8, the thermometer extends into the materials, and the temperature is configured to measure the temperature of the materials.

[0068] Embodiment 2: A method for analyzing the release durability of ester compounds in baijiu in a simulated oral cavity

[0069] I. Adjustment of simulated oral cavity parameters

[0070] The cavity of the simulated oral cavity is a 100 mL screw glass pool body, the cover is a hole polytetrafluoroethylene cover, and the cover is detachably arranged on the cavity.

[0071] ​The simulated oral cavity further comprises a beaker, the beaker is located outside the cavity, the cavity is placed in the beaker, the beaker is a double-layer water bath jacketed beaker, the outer capacity of the double-layer water bath jacketed beaker is 500 mL; the double-layer water bath jacketed beaker has a water inlet and a water outlet, the water inlet is arranged at the upper part of one side of the double-layer water bath jacketed beaker, the water outlet is arranged at the opposite side of the water outlet side of the double-layer water bath jacketed beaker, the water inlet is connected to a water bath kettle through a pipeline, the water bath kettle provides hot water to the double-layer water bath jacketed beaker through the water inlet through a pipeline, the hot water returns to the water bath kettle through the water outlet to form a water bath circulation, the water bath circulation is driven by a submersible pump, and the submersible pump is a micro submersible pump;

[0072] The channel is a silica gel hose pipeline, the water bath kettle is a constant temperature water bath kettle, and the setting temperature of the constant temperature water bath kettle is 40℃,

[0073] The cavity is provided with a stirrer at the bottom, the stirrer is a magnetic rotor, and the outside of the cavity is further provided with a magnetic stirrer body for rotating the magnetic rotor.

[0074] The magnetic stirrer and the rotor are used for mixing the sample in the cavity.

[0075] A thermometer is installed at the top of the cavity, the thermometer is a mercury thermometer; the thermometer is inserted into the inside of the pool body from above the cover body through a temperature measuring channel and contacts the liquid in the simulated oral cavity;

[0076] The thermometer is used for real-time monitoring of the temperature of the mixed liquid in the pool body, and the measurement range of the thermometer is 0-50℃.

[0077] The cavity is provided with a cover, the cover comprises a cover body and a channel, the channel is a pipeline arranged on the cover body, and the pipeline is a polytetrafluoroethylene pipe,

[0078] The channel comprises an air inlet channel, an air outlet channel, a sample adding channel, a temperature measuring channel and a sampling channel.

[0079] The air inlet channel and the air outlet channel are oppositely distributed, and the diameter is 8 mm. In addition, the air inlet channel is inserted into the cavity and arranged at a position 1-2 cm above the liquid surface, and the air outlet channel is inserted into the cavity and arranged at a position 1-2 cm below the lower edge of the cover body, so as to ensure that the gas is introduced from above the liquid surface and avoid direct escape of the gas, thereby enhancing the flow path and mixing efficiency of the gas in the cavity.

[0080] The sample adding channel and the temperature measuring channel are oppositely distributed, and the diameter is 6 mm.

[0081] The sampling channel is located at the center position relative to the air inlet channel, the air outlet channel, the sample adding channel and the temperature measuring channel, and has a diameter of 3 mm. The sampling channel is kept at a distance of 1.5 cm from the air inlet channel, the air outlet channel, the sample adding channel and the temperature measuring channel. The lower edge of the sampling channel is located at the middle of the air part in the cavity. The sampling channel is arranged on the cover body through a sealing ring to avoid gas leakage during the plugging process of the sampling channel. The lower edge of the sampling channel is configured to collect the "average gas state" of the volatile substances in the air after the liquid in the cavity is mixed.

[0082] Nitrogen is introduced into the air inlet channel. In some specific embodiments, the carrier gas is nitrogen, and the nitrogen is high-purity nitrogen. The purity of the nitrogen is ≥99.999%. The flow rate of the carrier gas is 150 mL / min, which is controlled by a gas flow meter.

[0083] The air inlet channel and the air outlet channel are both polytetrafluoroethylene pipes. The air inlet channel and the air outlet channel form a stable flow path for the gas in the pool body. The above design can effectively reduce the risk of oxidative degradation of aroma components and more truly reproduce the release dynamic process of aroma substances in the actual oral environment.

[0084] The beaker has a capacity of 500 mL. A double-layer water bath jacket is connected to a constant temperature water bath through a silica gel hose to maintain the system temperature at 37℃. The set temperature of the constant temperature water bath is slightly higher than the target temperature, which is set to 40℃. The water bath is driven by a miniature submersible pump. A stirrer is arranged at the bottom of the cavity. In this embodiment, the stirrer is a magnetic rotor. The bottom of the stirrer is also provided with a magnetic stirrer body. Under the action of the magnetic stirrer body, the magnetic rotor rotates to mix the sample in the pool body.

[0085] A mercury thermometer is installed at the top of the pool body to monitor the temperature of the mixed liquid in the pool body in real time (the measurement range is 0-50℃). High-purity nitrogen (purity ≥99.999%) is continuously introduced into the glass pool body at a flow rate of 150 mL / min through a 6*8 mm polytetrafluoroethylene pipe under the control of a gas flow meter. At the same time, the system is provided with another polytetrafluoroethylene pipe of the same specification as the air outlet channel to form a stable flow path for the gas in the pool body. The above design can effectively reduce the risk of oxidative degradation of aroma components and more truly reproduce the release dynamic process of aroma substances in the actual oral environment.

[0086] II. Qualitative and quantitative analysis of target ester compounds in liquor

[0087] (1) Analysis of high-content ester compounds

[0088] Direct injection (DI) combined with GC-FID (Gas Chromatography-Flame Ionization Detector) was used to analyze high content ester compounds in liquor.

[0089] Direct injection conditions: 1 mL of liquor sample was taken into a 2 mL chromatographic sample bottle, 50 μL of n-pentyl acetate (125.50 mg / L) was added as an internal standard, and 1 μL was directly injected after mixing evenly.

[0090] GC conditions: initial temperature 35℃, maintain running for 5 min; then from 35℃ to 100℃, the rate is 4℃ / min, maintain running for 2 min; then from 100℃ to 150℃, the rate is 8℃ / min; finally from 150℃ to 200℃, the rate is 15℃ / min, maintain running for 25 min. The carrier gas is helium with a purity of more than 99.999%, the flow rate is 1 mL / min, the split mode injection ratio is 20:1. The injection port and detector temperature are both 250℃.

[0091] Quantitative conditions: configure the mother liquor of high content target ester compounds, dilute the mother liquor into 10 concentration gradients according to 2 times dilution method, and the peak area ratio and concentration ratio of target and internal standard are used as the horizontal and vertical coordinates respectively to draw the standard curve.

[0092] (2) Analysis of low content ester compounds

[0093] Headspace-solid-Phase Microextraction (HS-SPME) combined with Comprehensive Two-Dimensional Gas Chromatography-Time-of-Flight Mass Spectrometry (GCxGC-TOFMS) was used to analyze low content ester compounds.

[0094] Headspace-solid-Phase Microextraction: pretreatment conditions: configure 5 mL of diluted liquor sample with alcohol content of 5% vol in a 20 mL headspace bottle, add 1.5 g of NaCl and 20 μL of 2-phenyl ethyl acetate-d3 (174.91 μg / L). Incubate the pretreated sample at 45℃ for 5 min, then extract at 400 rpm for 45 min. After extraction, immediately desorb at 250℃ for 5 min.

[0095] GCxGC conditions: The gas chromatograph was Agilent 7890B (Agilent, USA) equipped with two serial chromatographic columns, in which the first dimension chromatographic column was DB-FFAP capillary column (60 m x 0.25 mm x 0.25 μm, Agilent, USA), and the second dimension chromatographic column was Rxi-17Sil capillary column (1.5 m x 0.25 mm x 0.25 μm, Restek, USA). The column oven initial temperature was 45 °C, maintained for 3 min; then increased from 45 °C to 150 °C at a rate of 4 °C / min, maintained for 2 min; then increased from 150 °C to 200 °C at a rate of 6 °C / min; finally increased from 200 °C to 230 °C at a rate of 10 °C / min, maintained for 10 min. The carrier gas was helium with a purity of more than 99.999%, and the flow rate was 1 mL / min, with no split mode injection.

[0096] TOFMS conditions: The detector and transmission line temperature were set to 230 °C and 240 °C, respectively, the ion source voltage was 70 eV, the ion scanning range was 35-400 amu, and the scanning frequency was 100 spestra / s.

[0097] Quantitative conditions: The mother liquor of the low content target ester compounds was prepared, and the mother liquor was diluted into 10 concentration gradients according to the 2-fold dilution method. The peak area ratio of the target to the internal standard and the concentration ratio were taken as the horizontal and vertical coordinates, respectively, to draw the standard curve.

[0098] (3) Determination of the olfactory threshold of ester compounds in liquor and calculation of OAV (Odor Activity Value)

[0099] Each standard ester compound with a threshold concentration was diluted into 7 different concentrations with 50% vol ethanol aqueous solution, and the sensory evaluation data of 15 panelists were obtained by the three-point forced choice method, so as to obtain the olfactory threshold of each compound. According to the content of each compound and its olfactory threshold, the OAV of each compound can be calculated. According to the size of OAV, the ester aroma compounds with potential aroma contribution to the overall aroma of liquor were screened, i.e. the target ester compounds for exploring the aroma release persistence (OAV≥50), as shown in Table 1.

[0100] Table 1 Partial ester aroma compounds with potential aroma contribution to the overall aroma of liquor

[0101]

[0102]

[0103] III. Calculation of the aroma release persistence of ester compounds in simulated oral cavity

[0104] Based on the target ester compounds obtained in the qualitative and quantitative analysis of target ester compounds in liquor, the target ester compounds in the simulated oral cavity are analyzed, including the following steps:

[0105] 5 mL of liquor and 2 mL of artificial saliva are added to the simulated oral cavity, and magnetic stirring is performed at 40°C water bath for 2 s at a speed of 300 rpm. Then a handheld solid phase microextraction sampler (fiber head length of 2 cm, 50 / 30 μm, DVB / CAR / PDMS) is used to adsorb through the sampling channel and then extracted, and the extraction is performed in multiple times, each time for 2 min, and the interval time is 0 s, 30 s, 60 s, 120 s and 150 s, wherein 0 s refers to the initial time extraction after the addition of liquor and artificial saliva, 30 s refers to the extraction after 30 s interval after the addition of liquor and artificial saliva, 60 s refers to the extraction after 60 s interval after the addition of liquor and artificial saliva, and 120 s and 150 s are the same, each extraction is independent, and each extraction uses a newly configured sample.

[0106] The ester compounds in the extracted compounds are analyzed by using full two-dimensional gas chromatography-time of flight mass spectrometry (GCxGC-TOFMS) to obtain the release change curve of key ester aroma substances, so as to verify the practicability and response ability of the simulation system in the dynamic research of aroma release.

[0107] After the target ester compounds are extracted, the persistence of the target ester compound aroma release is based on the peak area ratio of 30 s, 60 s, 120 s and 150 s to 0 s. The peak area of the oral cavity aroma release and the size of the aroma persistence corresponding to different time intervals are shown in Tables 2 and Figure 3 .

[0108] Table 2 Peak area of target ester oral cavity aroma release and size of aroma persistence corresponding to different time intervals

[0109]

[0110]

[0111] From Tables 2 and Figure 4 , it can be seen that the experimental results show that after 150 s of simulated release, 2-methyl butyl acetate still maintains the highest aroma release intensity, followed by ethyl butyrate and 3-methyl butyl acetate, and the hydrophobic ethyl caproate rapidly decreases and shows the lowest persistence. Based on the constructed simulated oral cavity system, the oral cavity aroma release persistence of key ester compounds in liquor can be effectively distinguished. The results show the feasibility and practicability of the simulated oral cavity system in distinguishing the aroma release characteristics of ester compounds.

[0112] Comparative Example 1

[0113] Different from Example 1, the access depths of the air inlet channel and the air outlet channel in the simulated oral cavity in Comparative Example 1 are different. In Comparative Example 1, there are Control Group 1 and Control Group 2. In Control Group 1, the access depths of the air inlet channel and the air outlet channel are flush with the cover bottom of the cover body. In Control Group 2, the air inlet channel is inserted into the cavity and the lower edge of the air inlet channel is kept above the liquid surface by 2 cm, and the access depth of the air outlet channel is flush with the cover bottom of the cover body. The configuration of the mixed solution in the simulated oral cavity and the incubation parameters are the same as those in Example 1. Then, the headspace extraction is performed for 2 min at an interval of 0 s using a handheld solid-phase microextraction sampler, and the detection conditions of GCxGC-TOFMS are the same as those in Example 2. The total peak area of the ester compounds detected is shown in Table 2. Figure 2

[0114] As can be seen from Table 2, the three implementation manners have different effects on the gas flow path in the cavity and the collection efficiency of volatile components by adjusting the access depths of the air inlet channel and the air outlet channel. The ester compound collection efficiency of Example 1 is the best. Control Group 1 of the comparative example shows that the structure has obvious deficiencies in gas phase collection efficiency. Control Group 2 of the comparative example shows a certain degree of improvement, but the overall collection efficiency is still lower than that of Scheme 1. Figure 2 Comparative Example 2

[0115] The parameters of the simulated oral cavity are the same as those in Example 1. Different from Example 2, the extraction time of the handheld solid-phase microextraction sampler is adjusted. The length of each headspace extraction is adjusted to 1 min, 3 min and 4 min, respectively, and the detection conditions of GCxGC-TOFMS are the same as those in Example 2. The total peak area of the ester compounds detected is shown in Table 3.

[0116] Figure 3

[0117] As can be seen from Table 3, by comparing different headspace extraction times (1, 2, 3, and 4 min), the results show that the peak area of the ester compounds increases with time, but most of the esters are still in the initial release stage at 1 min, and the peak area is significantly lower than that at 2 min. Although the peak area increases at 3 min and 4 min, the increase is not significant. Considering the release efficiency and timeliness of detection, 2 min is a relatively optimal extraction time, which can realize the sufficient release of key ester compounds and is suitable for subsequent analysis. Figure 3 The present application can analyze the aroma release durability of ester compounds in liquor by constructing a simulated oral cavity to simulate the changes of liquor in the human oral cavity and analyzing the aroma release durability of ester compounds in liquor in the simulated oral cavity. The method can analyze ester compounds with strong aroma release durability in liquor, which have important value and significance for liquor production.

[0118]

[0119] ​​​​It is to be understood that the application is described herein by way of several embodiments, and that modifications and / or changes can be suggested as equivalents thereof without departing from the spirit and scope of the application. In addition, where features or aspects of the application are described in terms of Markush groups or other grouping of alternatives, those skilled in the art will recognize that individual substituents from a group can be replaced by other substituents from the same group or from different groups. All such possibilities are specifically intended and are within the scope of the application.

Claims

1. A simulated oral cavity comprising a working state, characterized in that, The simulation oral cavity comprises: a cavity (1) configured to store materials; the cavity is equipped with a cover (2) comprising a cover body and channels, the channels comprising: an air inlet channel (3), an air outlet channel (4), a sample addition channel (10) and a sampling channel (5); the air inlet channel (3) and the air outlet channel (4) are oppositely arranged on the cover body, and the sampling channel is arranged in the center of the cover body; in the working state, the air inlet channel (3) and the air outlet channel (4) are inserted into the cavity, and the lower edge of the air inlet channel (3) is arranged at a position 1-2 cm above the materials; the lower edge of the air outlet channel (4) is arranged at a position 1-2 cm away from the lower edge of the cover body; a stirrer arranged inside the cavity (1).

2. The simulation oral cavity according to claim 1, wherein in the working state, the simulation oral cavity comprises a temperature control device configured to control the temperature of the materials stored in the cavity, and the channels further comprise a temperature measuring channel (8).

3. The simulated oral cavity of claim 1, wherein, The stirrer comprises a magnetic rotor (6), and the cavity is further provided with a magnetic stirrer body (9) outside the cavity for rotating the magnetic rotor; the temperature control device is a constant temperature water bath (11).

4. A method for analyzing the long-lasting oral aroma release of ester compounds in Baijiu, characterized in that, The method is based on the simulation oral cavity according to any one of claims 1-3 to analyze the oral aroma release durability of ester compounds in liquor, comprising the following steps: I. filling the cavity of the simulation oral cavity with carrier gas, adding liquor and artificial saliva, and mixing; II. sampling and analyzing the volatile gas after the mixture of liquor and artificial saliva, the sampling and analyzing comprising independent sampling and analyzing at multiple time points; III. determining the oral aroma release durability of ester compounds in liquor at different time points by comparing the ratio of the peak area of ester compounds obtained at different time points to the peak area at the initial time.

5. The analysis method according to claim 4, characterized in that, The ester compound is an ester compound with an odor activity value ≥ 50; Preferably, the ester compound with an odor activity value ≥ 50 comprises: 3-methyl butyric acid ethyl ester, 2-methyl butyric acid ethyl ester, butyric acid ethyl ester, hexanoic acid ethyl ester, 2-methyl propionic acid ethyl ester, 4-methyl pentanoic acid ethyl ester, and valeric acid ethyl ester.

6. The analysis method according to claim 4, characterized in that, The filling of the carrier gas into the cavity of the simulation oral cavity comprises: filling the cavity of the simulation oral cavity with carrier gas at a flow rate of 120-180 mL / min; Preferably, the carrier gas is nitrogen.

7. The analysis method of claim 4, wherein, The sampling and analyzing is extraction analysis, and the extraction time is 1.8-2.2 min.

8. The analysis method according to claim 4, characterized in that, The independent sampling and analyzing at multiple time points comprises: sampling and analyzing the volatile gas obtained after the mixture of liquor and artificial saliva is left for 0 s, 30 s, 60 s, 120 s and 150 s.

9. The extraction analysis comprises: The hand-held solid phase microextraction sampler is adsorbed through the sampling channel and then extracted, and the ester compounds in the extracted compounds are analyzed by full two-dimensional gas chromatography-time of flight mass spectrometry.

10. Application of an ester compound in the field of Baijiu, characterized in that, The ester compound comprises at least one of 2-methyl butyric acid ethyl ester, butyric acid ethyl ester, 3-methyl butyric acid ethyl ester and valeric acid ethyl ester.

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