Method for quickly predicting the number of times of use of oak barrels based on a model of barrel aging flavors of alcoholic beverages

Abstract

This invention provides a method for rapidly predicting the number of times oak barrels can be used based on a wine barrel aging flavor model, belonging to the field of wine testing technology. This method employs multiple ultrasonic extractions combined with solid-phase microextraction-gas chromatography-mass spectrometry to detect the content of oak flavor substances in barrel-aged wines, rapidly simulating the oak flavor threshold during barrel aging to predict the maximum number of times oak barrels can be used for different wine products. This method allows winemakers to quickly predict the flavor utilization limits of different oak barrels during the production of barrel-aged wines, providing a basis for more rational barrel selection, usage, and efficient utilization of oak barrels.

Description

Technical Field

[0001] This invention belongs to the field of wine testing technology, and in particular relates to a method for rapidly predicting the number of times an oak barrel has been used based on a wine barrel aging flavor model. Background Technology

[0002] Barrel aging is an ancient traditional technique still used today to improve the sensory quality of wines, spirits, and some specialty beers. Currently, with the gradual development of my country's economy and the continuous improvement of people's living standards, the consumer base for ultra-premium beers is also gradually expanding. Different educational levels, purchasing power, and living environments lead to varying consumer demands for beer, while the pace of innovation in high-quality products is not as fast as expected. The emergence of premium barrel-aged beers alleviates this contradiction.

[0003] The cis and trans-lactones, phenolic compounds, and volatile phenolic compounds in oak have a significant impact on the oak flavor and mouthfeel of the spirit. The barrel aging process produces a dramatic change in the flavor profile, with a noticeable increase in coconut, cream, woody, and vanilla notes. Oak flavors, represented by oak lactones, furans, and phenolic compounds, contribute over 60% of the final flavor profile.

[0004] Oak trees belong to the genus *Quercus* in the family Fagaceae. Their maturation cycle is long; a single oak tree needs to live for at least a century to meet the requirements for oak barrel making. In recent years, with the increasing production of barrel-aged alcoholic beverages such as whisky, the demand for oak has also grown significantly. However, the oak's slow growth cycle is increasingly unable to meet market demand, leading to a continuous shrinking of oak-producing regions. Therefore, the efficient utilization of oak barrels is urgently needed. Developing a method to complete an enhanced extraction test within 5 minutes and determine the flavor limits of different oak species for various barrel-aged products within 24 hours has become a primary task.

[0005] Traditional oak fortification experiments typically employ a milder, longer immersion method, using a 60% ethanol solution (the alcohol content of the whisky at the time of cask entry) for 3-6 months to simulate 3-4 years of cask aging. However, this method is too time-consuming, making it unsuitable for short-term product design and other needs. Magnetic stirring can shorten this cycle to 12 hours, but this still cannot fully meet the need for intensification extraction experiments completed within 5 minutes, requiring rapid prediction on the same day. This rapid prediction technology is precisely what is crucial when frequent fine-tuning of the product flavor is required in the later stages of whisky design. Summary of the Invention

[0006] This invention provides a method for rapidly predicting the number of times oak barrels can be used based on a wine barrel aging flavor model. This allows winemakers to quickly predict the maximum number of times different oak barrels can be used during the production of barrel-aged wines, providing a basis for more rational selection, use, and efficient utilization of oak barrels.

[0007] To achieve the above objectives, this invention provides a method for rapidly predicting the number of times oak barrels can be used based on a wine barrel aging flavor model. The method employs multiple ultrasonic extractions combined with solid-phase microextraction-gas chromatography-mass spectrometry to detect the content of oak flavor substances in barrel-aged wine products, rapidly simulating the oak flavor threshold of barrel-aged wine products during the barrel aging process, so as to predict the maximum number of times oak barrels can be used for different wine products.

[0008] As a preferred method, during multiple ultrasonic extraction processes, when the content of oak flavor substances approaches or falls below its flavor threshold, the corresponding oak barrel is determined to be no longer usable; in this process, the number of ultrasonic extractions corresponds to the maximum number of times the oak barrel can be used in the actual barrel aging process.

[0009] Preferably, the oak flavoring substances are guaiacol, cis-oak lactone, eugenol, and vanillin.

[0010] As a preferred option, a simulation curve equation was established for the relationship between different barrel aging times and the content of oak flavor compounds in barrel-aged wines, specifically as follows:

[0011] American oak chips:

[0012] Guaiacin: Y = 1056e -0.597x R 2 =0.9697;

[0013] cis-oak lactone: Y = 8532.8e -0.816x R 2 =0.9691;

[0014] Eugenol: Y = 4179.5e -0.727x R 2 =0.9921;

[0015] Vanillin: Y = 15716e -0.739x R 2 =0.9849.

[0016] French oak chips:

[0017] Guaiacin: Y = 410.41e -0.814x R 2 =0.9982;

[0018] cis-oak lactone: Y = 1551.5e -0.821x R 2 =0.9983;

[0019] Eugenol: Y = 490.17e -0.764x R 2 =0.9926;

[0020] Vanillin: Y = 12369e -0.804x R 2 =0.9997.

[0021] As preferred, the flavor thresholds of oak flavor compounds are as follows: guaiacol ≥ 95 μg / L, cis oak lactone ≥ 67 μg / L, eugenol ≥ 500 μg / L, and vanillin ≥ 320 μg / L.

[0022] As a preferred method, multiple ultrasonic extraction specifically involves:

[0023] Weigh 0.04g of heavily carbonized oak chips and place them in a test bottle. Add 2mL of ethanol / water, use 180W ultrasonic power, control the temperature to be less than 20℃, and set the ultrasonic time to 5min.

[0024] After sonication, the solution was filtered into a 20 mL headspace vial and diluted to an ethanol concentration of ≤20% for subsequent solid-phase microextraction-gas chromatography-mass spectrometry analysis.

[0025] The remaining oak chips were dried at 100°C for 2 hours to remove moisture and ethanol, in preparation for ultrasonic extraction again.

[0026] Preferably, the oak is American oak or French oak. For American oak, the volume ratio of ethanol to water is set to 60:40, and the pH is 5.5.

[0027] For French oak, the volume ratio of ethanol to water was set at 12.5:87.5, and the pH was 4.

[0028] Understandably, the above scheme uses the treatment of American oak to simulate the barrel aging process of bourbon whiskey and the treatment of French oak to simulate the barrel aging process of wine and brandy, in order to predict the maximum number of times oak barrels can be used.

[0029] Preferably, the ultrasonic extraction is performed 1-5 times.

[0030] As a preferred method, the solid-phase microextraction conditions are as follows: fiber extraction head: 65μm DVB / CAR / PDMS extraction head; extraction temperature: 40℃; pre-heating time: 2 min; extraction time: 15 min; elution time: 3 min.

[0031] As a preferred option, the gas chromatography-mass spectrometry conditions are:

[0032] A weakly polar capillary column (60 m × 0.32 mm × 0.25 μm) was used, with nitrogen as the carrier gas and a flow rate of 1.5 mL / min.

[0033] The column heating program is as follows: hold at 35℃ for 2 min, then increase to 60℃ at 7.5℃ / min and hold for 0.5 min, then increase to 240℃ at 15℃ / min and hold for 15 min;

[0034] The injection port temperature is 250℃, the electron bombardment energy is 70eV, and the ion source temperature is 230℃.

[0035] Preferably, the standard mass spectrometry library for oak flavor compounds is the NIST standard mass spectrometry library.

[0036] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0037] This invention provides a method for rapidly predicting the number of times oak barrels can be used based on a barrel aging flavor model. This method is applicable to predicting the flavor potential of oak barrels during the barrel aging process for alcoholic beverages (beer, wine, brandy, and whiskey, etc.) with different ethanol contents. It enables winemakers to quickly predict the maximum number of times different oak barrels can be used to enhance the oak flavor of different alcoholic beverages during the production of barrel-aged products, providing a basis for more rational barrel selection and efficient utilization of oak barrels. Attached Figure Description

[0038] Figure 1 GC-MS selected ion map of flavor compounds in ultrasonically treated oak chips provided in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram illustrating the attenuation of residual flavor substances from American oak after multiple ultrasonic extractions, provided in an embodiment of the present invention.

[0040] Figure 3 This is a schematic diagram illustrating the attenuation of residual flavor substances from French oak after multiple ultrasonic extractions, as provided in an embodiment of the present invention. Detailed Implementation

[0041] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Example 1

[0043] Oak sample: American oak chips (suitable for barrel aging of bourbon whiskey) were carbonized at 225°C for 15 minutes to obtain heavily carbonized oak chips.

[0044] Sample preparation: Take 0.04g of heavily carbonized oak chips in five separate batches and add them to different test bottles, and add 2mL of ethanol / water (60% v / v, pH=5.5, simulating the alcohol content of whiskey in barrels).

[0045] Ultrasonic treatment: 180W ultrasonic power was used, the temperature was controlled to be less than 20℃, and the ultrasonic time was set to 5min. After ultrasonication, the sample was filtered into a 20mL headspace vial and diluted to an ethanol concentration of less than 20% for subsequent solid phase microextraction-gas chromatography-mass spectrometry analysis.

[0046] The remaining oak shavings were dried at 100°C for 2 hours in preparation for ultrasonic use again until all oak flavor substances were below their oak flavor threshold.

[0047] Sample analysis:

[0048] Solid-phase microextraction conditions: fiber extraction head: 65μm DVB / CAR / PDMS; extraction temperature: 40℃; pre-heating time: 2 min; extraction time: 15 min; elution time: 3 min.

[0049] Gas chromatography-mass spectrometry conditions:

[0050] A weakly polar capillary column (60 m × 0.32 mm × 0.25 μm) was used, with nitrogen as the carrier gas and a flow rate of 1.5 mL / min.

[0051] The column heating program is as follows: hold at 35℃ for 2 min, then increase to 60℃ at 7.5℃ / min and hold for 0.5 min, then increase to 240℃ at 15℃ / min and hold for 15 min;

[0052] The injection port temperature is 250℃, the electron bombardment energy is 70eV, and the ion source temperature is 230℃.

[0053] Qualitative analysis of samples: The National Institute of Standards and Technology (NIST) standard mass spectrometry library was used.

[0054] Quantitative analysis of samples: Quantification was performed using a calibration curve based on a standard reference material (Sigma-Aldrich).

[0055] like Figure 1 and 2 As shown, the main flavor compounds in the extracts from each oak barrel were guaiacol, cis-oakol, eugenol, and vanillin. After five rounds of extraction tests, the content of oak flavor compounds eventually decreased to below the threshold (as shown in Table 1), indicating a high correlation between the number of ultrasonic extractions and the content of oak flavor compounds (R). 2 >96%.

[0056] Table 1. Residual concentrations of American oak flavor compounds after multiple ultrasonic extractions.

[0057]

[0058] As shown in Table 1, after the fourth ultrasonic treatment, the residual concentration of guaiacol was below its flavor threshold. This indicates that if American oak barrels are used, a maximum of three barrels are needed to meet the flavor requirements for guaiacol. Similarly, after the fifth ultrasonic treatment, the residual concentration of cis-oakol was below its flavor threshold; after the first ultrasonic treatment, the residual concentration of eugenol was below its flavor threshold; and after the fourth ultrasonic treatment, the residual concentration of vanillin was below its flavor threshold. In conclusion, if American oak barrels are to be used, considering the flavor thresholds of the above flavor substances, new barrels or single-use barrels should be selected.

[0059] Example 2

[0060] Oak sample: French oak chips (suitable for barrel aging of wine and brandy) were carbonized at 180°C for 5 minutes to obtain lightly carbonized oak chips.

[0061] Sample preparation: 0.04 g of lightly carbonized oak chips were added to different test bottles in five separate batches, and 2 mL of ethanol / water (12.5% ​​v / v, pH=4, simulating the barrel aging process of wine) was added.

[0062] Ultrasonic treatment: 180W ultrasonic power was used, the temperature was controlled to be less than 20℃, and the ultrasonic time was set to 5min. After ultrasonication, the sample was filtered into a 20mL headspace vial for subsequent solid phase microextraction-gas chromatography-mass spectrometry analysis.

[0063] The remaining oak shavings were dried at 100°C for 2 hours in preparation for ultrasonic reuse until all oak flavor compounds were below their oak flavor threshold.

[0064] Sample analysis:

[0065] Solid-phase microextraction conditions: fiber extraction head: 65μm DVB / CAR / PDMS; extraction temperature: 40℃; pre-heating time: 2 min; extraction time: 15 min; elution time: 3 min.

[0066] Gas chromatography-mass spectrometry conditions:

[0067] A weakly polar capillary column (60 m × 0.32 mm × 0.25 μm) was used, with nitrogen as the carrier gas and a flow rate of 1.5 mL / min.

[0068] The column heating program is as follows: hold at 35℃ for 2 min, then increase to 60℃ at 7.5℃ / min and hold for 0.5 min, then increase to 240℃ at 15℃ / min and hold for 15 min;

[0069] The injection port temperature is 250℃, the electron bombardment energy is 70eV, and the ion source temperature is 230℃.

[0070] Qualitative analysis of samples: The National Institute of Standards and Technology (NIST) standard mass spectrometry library was used.

[0071] Quantitative analysis of samples: Quantification was performed using a calibration curve based on a standard reference material (Sigma-Aldrich).

[0072] like Figure 3 As shown in Table 2, the main flavor compounds in the extracts from each oak barrel were guaiacol, cis-oakol, eugenol, and vanillin. After four rounds of extraction tests, the content of oak flavor compounds eventually decreased to below the threshold (as shown in Table 2). This indicates a high correlation between the number of ultrasonic extractions and the content of French oak flavor compounds (R0). 2 >99%).

[0073] Table 2. Residual concentrations of French oak flavor compounds after multiple ultrasonic extractions.

[0074]

[0075] As shown in Table 2, after the first ultrasonic treatment, the residual concentration of guaiacol was already below its flavor threshold. This indicates that if French oak barrels are used, only one barrel is needed at most to meet the flavor requirements for guaiacol. Similarly, after the second ultrasonic treatment, the residual concentration of cis-oakolactone was already below its flavor threshold, and after the third ultrasonic treatment, the residual concentration of vanillin was also below its flavor threshold. In conclusion, if French oak barrels are to be used, then considering the flavor thresholds of the above flavor substances, new barrels should be selected.

Claims

1. A method for rapidly predicting the number of times an oak barrel has been used based on a wine barrel aging flavor model, characterized in that, The content of oak flavor substances in barrel-aged wines was detected by multiple ultrasonic extractions combined with solid-phase microextraction-gas chromatography-mass spectrometry. This method rapidly simulates the oak flavor threshold of barrel-aged wines during the barrel aging process, in order to predict the maximum number of times oak barrels can be used for different wine products. During multiple ultrasonic extraction processes, when the content of oak flavor compounds approaches or falls below its flavor threshold, the corresponding oak barrel is determined to be no longer usable. In this process, the number of ultrasonic extractions corresponds to the maximum number of times the oak barrel can be used in the actual barrel aging process. The oak flavor compounds are guaiacol, cis-oak lactone, eugenol and vanillin; The flavor thresholds for oak flavor compounds are as follows: guaiacol ≥ 95 μg / L, cis-oak lactone ≥ 67 μg / L, eugenol ≥ 500 μg / L and vanillin ≥ 320 μg / L.

2. The method according to claim 1, characterized in that, A simulation curve equation was established for the relationship between different barrel aging times and the content of oak flavor compounds in barrel-aged wines. Specifically, American oak chips: Guaiacin: Y=1056e -0.597x R 2 =0.9697; cis-oak lactone: Y=8532.8e -0.816x R 2 =0.9691; Eugenol: Y=4179.5e -0.727x R 2 =0.9921; Vanillin: Y=15716e -0.739x R 2 =0.9849; French oak chips: Guaiacin: Y=410.41e -0.814x R 2 =0.9982; cis-oak lactone: Y = 1551.5e -0.821x R 2 =0.9983; Eugenol: Y=490.17e -0.764x R 2 =0.9926; Vanillin: Y=12369e -0.804x R 2 =0.9997.

3. The method according to claim 1, characterized in that, Multiple ultrasonic extractions specifically involve: Weigh 0.04g of carbonized oak sawdust into a test bottle, add 2mL of ethanol / water, use 180W ultrasonic power, control the temperature to be less than 20℃, and set the ultrasonic time to 5min; After sonication, the solution was filtered into a 20 mL headspace vial and diluted to an ethanol concentration of ≤20% for subsequent solid-phase microextraction-gas chromatography-mass spectrometry analysis. The remaining oak chips were dried at 100°C for 2 hours to remove moisture and ethanol, in preparation for ultrasonic extraction again.

4. The method according to claim 3, characterized in that, The oak is American oak or French oak; For American oak, it was heavily roasted at 230°C for 15 minutes, with the volume ratio of ethanol to water set at 60:40 and pH=5.

5. For French oak, it was lightly roasted at 180°C for 5 minutes, with the volume ratio of ethanol to water set at 12.5:87.5 and pH=4.

5. The method according to claim 3, characterized in that, The number of ultrasonic extractions is 1-5 times.

6. The method according to claim 1, characterized in that, Solid-phase microextraction conditions: Fiber extraction head: 65µm DVB / CAR / PDMS extraction head; Extraction temperature: 40℃; Preheating time: 2 min; extraction time: 15 min; desorption time: 3 min.

7. The method according to claim 1, characterized in that, Gas chromatography-mass spectrometry conditions: A weakly polar capillary column (60 m × 0.32 mm × 0.25 μm) was used, with nitrogen as the carrier gas and a flow rate of 1.5 mL / min. The column heating program is as follows: hold at 35℃ for 2 min, then increase to 60℃ at 7.5℃ / min and hold for 0.5 min, then increase to 240℃ at 15℃ / min and hold for 15 min; The injection port temperature is 250℃, the electron bombardment energy is 70eV, and the ion source temperature is 230℃.

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