Method for improving quality of l-menthol product

Abstract

A method for improving the quality of an L-menthol product, comprising the following steps: laying L-menthol to be treated to form an L-menthol material layer, and then carrying out curing treatment, wherein the curing treatment needs to meet the following conditions at the same time: the average particle size L of said L-menthol is 0.5-2 cm, the thickness D of the L-menthol material layer is 1-50 cm, the temperature T of the curing treatment is 10-50°C, the time t of the curing treatment is 0.1-24 h, and L, D, T and t need to meet the following relational expression: [Equation].

Description

A method for improving the quality of L-menthol products Technical Field

[0001] The invention relates to the technical field of L-menthol preparation, and in particular to a method for improving the quality of L-menthol products. Background Art

[0002] Menthol, also known as menthol, has a chemical formula of C 10 H 20 Menthol is a terpene organic compound that occurs naturally in plants of the mint family. Its distinctive minty aroma and refreshing cooling sensation are widely used in food, medicine, tobacco, and other fields, making it one of the world's most widely used monomeric fragrances. However, the menthol molecule contains three chiral centers and has eight isomers. While the physical properties of these isomers are similar, their odor and cooling sensation differ significantly. Commercially available menthol products are often mixtures of these eight isomers. Due to the varying content of each isomer in the mixture, the odor and cooling sensation of menthol products vary greatly, and product quality also varies.

[0003] Chinese patent CN101821221B discloses a method for preparing menthol, which is obtained by hydrogenating isopulegol in the presence of a catalyst. The patent discloses information such as the catalyst composition and hydrogenation conditions, but does not mention the product flavor and cooling sensation.

[0004] Chinese patent CN101679163B discloses a method for preparing menthol flakes, which is produced by contacting molten menthol with two separated cooling surfaces. The patent only mentions the production method of the menthol flakes, but does not mention the characteristic flavor and cooling quality of the menthol flakes, nor does it mention how to process the menthol to improve its product quality.

[0005] The document "THE CRYSTALLIZATION OF MENTHOL" (FRED.E.WRIGHT, The Journal of The American Chemical Society) mentions that menthol has at least four crystal forms, namely α, β, γ, and δ, and that the four crystal forms can transform into each other. However, it does not provide clear transformation conditions, nor does it mention the relationship between crystal form transformation and product quality.

[0006] How to improve the quality of menthol products, especially to enhance the quality in terms of flavor purity and cooling sensation, remains one of the technical issues that require breakthroughs in this field.

[0007] Summary of the Invention

[0008] The present invention provides a method for improving the quality of an L-menthol product. By subjecting the L-menthol to a aging treatment according to the method of the present invention, the quality of the L-menthol product can be significantly improved, and the quality of the L-menthol product in terms of the purity of its characteristic odor and its cooling and penetrating properties can be enhanced.

[0009] To achieve its purpose, the present invention provides the following technical solutions:

[0010] The present invention provides a method for improving the quality of L-menthol products, comprising the following steps:

[0011] The L-menthol to be processed is laid to form a menthol material layer, and then subjected to a aging treatment, and the aging treatment must simultaneously meet the following conditions:

[0012] The average particle size L of the L-menthol to be treated is 0.5-2 cm, the thickness D of the L-menthol material layer is 1-50 cm, the temperature T of the aging treatment is 10-50° C., the time t of the aging treatment is 0.1-24 h, and L, D, T and t must satisfy the following relationship:

[0013] In the above relationship, L is the average particle size of the L-menthol to be treated, in cm; D is the thickness of the L-menthol material layer, in cm; T is the aging temperature, in ° C; and t is the aging time, in h.

[0014] After extensive research, the inventors have discovered that aging L-menthol according to the aforementioned conditions can improve the purity of the characteristic odor and the cooling, penetrating properties of L-menthol products. Specifically, during the aging process, the average particle size L of the L-menthol to be treated must be 0.5-2 cm, the thickness D of the L-menthol material layer must be 1-50 cm, the aging temperature T must be 10-50° C., and the aging time t must be 0.1-24 hours. Furthermore, the values ​​of L, D, T, and t must satisfy the aforementioned relationship. When these conditions are met, aging L-menthol significantly improves the quality of the L-menthol product.

[0015] In some embodiments, the average particle size L of the L-menthol to be processed is, for example, 0.5, 0.8, 1, 1.2, 1.5, or 2 cm. In some embodiments, the thickness D of the L-menthol material layer is, for example, 1, 2, 5, 7, 8, 10, 15, 20, 25, 30, 35, 40, 45, or 50 cm. In some embodiments, the aging temperature T is, for example, 10, 15, 20, 25, 30, 35, 40, 45, or 50° C. In some embodiments, the aging time t is, for example, 0.1, 0.5, 1, 5, 10, 12, 15, 20, or 24 hours. In each of the above examples, L, D, T, and t must also satisfy the relationship described above.

[0016] In some embodiments, the average particle size L of the L-menthol to be treated is 0.5-1.5 cm.

[0017] In some embodiments, the thickness D of the L-menthol material layer is 1-10 cm.

[0018] In some embodiments, the temperature T of the aging treatment is 20-40°C.

[0019] In some embodiments, the aging treatment time t is 1-12 hours.

[0020] In some preferred embodiments, the average particle size L of the L-menthol to be treated is 0.5-1.5 cm, the thickness D of the L-menthol material layer is 1-10 cm, the aging temperature T is 20-40°C, and the aging time t is 1-12 hours. This preferred method for aging L-menthol further improves the quality of the L-menthol product, achieving both enhanced aroma purity and cooling properties.

[0021] Furthermore, the L-menthol to be processed is formed L-menthol; preferably, the formed L-menthol is in the form of flakes, blocks or spheres.

[0022] Herein, "aging treatment" refers to the process of keeping the L-menthol to be treated in a certain form at a certain temperature for a period of time.

[0023] Herein, the "average particle size of the L-menthol to be treated" refers to the D50 value of the sample, which can be obtained by a particle size testing device known in the art, such as the BT-2900 (with a 0.132x lens) produced by Dandong Better Instrument Co., Ltd.

[0024] In this article, "odor purity" refers to the degree to which an L-menthol product exhibits a distinctive, distinct, and characteristic L-menthol aroma without any other foreign odors. The product's odor purity is evaluated by comparing the odor of the L-menthol product to that of an L-menthol standard. Specific evaluation methods are described below.

[0025] In this article, "cooling penetration" refers to the cooling diffusion and penetration properties of L-menthol products. The quality of a product's cooling penetration is evaluated by comparing the cooling sensation of an L-menthol product with that of an L-menthol standard sample after application. Specific evaluation methods are described below.

[0026] In some embodiments, the chemical purity of the L-menthol to be processed is greater than 95 wt %; preferably, the chemical purity of the menthol to be processed is greater than 99 wt %.

[0027] By carrying out a ripening treatment on L-menthol using the method of the present invention, a high-quality L-menthol product can be obtained. The product has a pure characteristic flavor of L-menthol and a strong sense of transparency.

[0028] In the present invention, the aging equipment required for the aging process is not particularly limited. Any equipment that can provide the required environment and conditions for aging can be used. For example, the aging equipment may include components that can form a layer of L-menthol material to be treated, and a space that can hold the L-menthol material layer for aging under the required temperature conditions. Specifically, the aging equipment used may be, but is not limited to, box-type, kettle-type, crawler-type, or plate-type equipment, such as an oven.

[0029] The technical solution provided by the present invention has the following beneficial effects:

[0030] The present invention performs a aging treatment on L-menthol and controls the aging treatment conditions to meet specific requirements, thereby significantly improving the purity of the characteristic odor and the cooling and permeability of the product without increasing the purity of the L-menthol product. In addition, the aging treatment of the present invention does not require complicated equipment and operation procedures, and the process is simple and convenient, thereby having high practical value. DETAILED DESCRIPTION

[0031] In order to facilitate the understanding of the present invention, the present invention will be further described below in conjunction with examples. It should be understood that the following examples are only for a better understanding of the present invention and do not mean that the present invention is limited to the following examples.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The term "and / or" as may be used herein includes any and all combinations of one or more of the associated listed items.

[0033] Where specific experimental steps or conditions are not specified in the examples, the corresponding conventional experimental steps or conditions in the art can be used. Reagents or instruments used without specifying the manufacturer are all commercially available conventional products.

[0034] The main raw materials used in the embodiments and comparative examples are as follows:

[0035] L-Menthol to be matured: chemical purity 99.90 wt%, Aladdin Reagent Co., Ltd.

[0036] The testing instrument for the average particle size (D50) in the following examples and comparative examples is: Dandong Better Instrument Co., Ltd., dynamic image particle size and shape analyzer BT-2900 (with a 0.132x lens).

[0037] In the following examples, the aging treatment of the L-menthol to be treated was carried out under the following conditions:

[0038] The L-menthol to be processed is formed into an average particle size L controlled to be 0.5-2 cm, the thickness D of the laid L-menthol material layer is controlled to be 1-50 cm, the aging temperature T is controlled to be 10-50° C., and the aging time t is controlled to be 0.1-24 h. The four parameters L, D, T, and t must satisfy the following relationship:

[0039] The detailed description of the aging treatment of the L-menthol to be aging in each embodiment and comparative example is given below.

[0040] Example 1

[0041] The L-menthol to be matured was placed in a jacketed flask, and 50° C. warm water was introduced into the jacket. The L-menthol to be matured was melted and poured into a mold to form spherical particles, thereby obtaining L-menthol to be matured with an average particle size (D50) of 1.5 cm.

[0042] The L-menthol to be matured prepared by the above process was laid on a flat plate of a maturation device to obtain a 30 cm thick L-menthol material layer. The material was then left in the maturation device at a temperature of 30°C for 3 hours to obtain a matured L-menthol product, which was then evaluated.

[0043] Example 2

[0044] The L-menthol to be matured was placed in a jacketed flask, and 50°C warm water was introduced into the jacket. The L-menthol to be matured was melted and poured into a mold to form spherical particles, thereby obtaining L-menthol to be matured with an average particle size (D50) of 0.5 cm.

[0045] The L-menthol to be matured prepared by the above process was spread on a flat plate to obtain a 50 cm thick L-menthol material layer. The material was then placed in a maturation device at a temperature of 10°C for 10 hours to obtain a matured L-menthol product, which was then evaluated.

[0046] Example 3

[0047] The L-menthol to be matured was placed in a jacketed flask, and 50° C. warm water was introduced into the jacket. The L-menthol to be matured was melted and poured into a mold to form spherical particles, thereby obtaining L-menthol to be matured with an average particle size (D50) of 1.5 cm.

[0048] The L-menthol to be matured prepared by the above process was laid on a flat plate of a maturation device to obtain an L-menthol material layer with a thickness of 8 cm. The material was then left in the maturation device at a temperature of 30°C for 12 hours to obtain a matured L-menthol product, which was then evaluated.

[0049] Example 4

[0050] The L-menthol to be matured was placed in a jacketed flask, and 50° C. warm water was introduced into the jacket. The L-menthol to be matured was melted and poured into a mold to form spherical particles, thereby obtaining L-menthol to be matured with an average particle size (D50) of 2 cm.

[0051] The L-menthol to be matured prepared by the above process was laid on a flat plate of a maturation device to obtain a 1 cm thick L-menthol material layer. The material was then left in the maturation device at a temperature of 50°C for 12 hours to obtain a matured L-menthol product, which was then evaluated.

[0052] Comparative Example 1

[0053] The L-menthol to be matured was placed in a jacketed flask, and 50° C. warm water was introduced into the jacket. The L-menthol to be matured was melted and poured into a mold to form spherical particles, thereby obtaining L-menthol to be matured with an average particle size (D50) of 2 cm.

[0054] The L-menthol to be matured prepared by the above process was laid on a flat plate of a maturation device to obtain a 55 cm thick L-menthol material layer. The material was then left in the maturation device at a temperature of 30°C for 24 hours to obtain a matured L-menthol product, which was then evaluated.

[0055] Comparative Example 2

[0056] The L-menthol to be matured was placed in a jacketed flask, and 50° C. warm water was introduced into the jacket. The L-menthol to be matured was melted and poured into a mold to form spherical particles, thereby obtaining L-menthol to be matured with an average particle size (D50) of 0.5 cm.

[0057] The L-menthol to be matured prepared by the above process was laid on a flat plate of a maturation device to obtain a 50 cm thick L-menthol material layer. The material was then left in the maturation device at a temperature of 10°C for 3 hours to obtain a matured L-menthol product, which was then evaluated.

[0058] Comparative Example 3

[0059] L-menthol to be matured was placed in a jacketed flask, and 50°C warm water was passed into the jacket. The L-menthol to be matured was melted and poured into a mold to form spherical particles. The resulting L-menthol to be matured had an average particle size (D50) of 0.5 cm. The resulting L-menthol to be matured was then evaluated.

[0060] Comparative Example 4

[0061] The L-menthol to be matured was placed in a jacketed flask, and 50° C. warm water was introduced into the jacket. The L-menthol to be matured was melted and poured into a mold to form spherical particles, thereby obtaining L-menthol to be matured with an average particle size (D50) of 2 cm.

[0062] The L-menthol to be matured prepared by the above process was laid on a flat plate of a maturation device to obtain a 1 cm thick L-menthol material layer. The material was then left in the maturation device at a temperature of 5°C for 12 hours to obtain a matured L-menthol product, which was then evaluated.

[0063] Comparative Example 5

[0064] The L-menthol to be matured was placed in a jacketed flask, and 50° C. warm water was introduced into the jacket. The L-menthol to be matured was melted and poured into a mold to form spherical particles, thereby obtaining L-menthol to be matured with an average particle size (D50) of 3 cm.

[0065] The L-menthol to be matured prepared by the above process was laid on a flat plate of a maturation device to obtain a 55 cm thick L-menthol material layer. The material was then left in the maturation device at a temperature of 5°C for 12 hours to obtain a matured L-menthol product, which was then evaluated.

[0066] The aging conditions of Examples 1-4 and Comparative Example 2 are summarized in Table 1 below.

[0067] Table 1

[0068] The evaluation methods for evaluating the products in the examples and comparative examples are as follows:

[0069] A professional fragrance evaluation team conducted a quality evaluation on the L-menthol products obtained in each embodiment and comparative example based on two dimensions: odor purity and cool penetration. The full score is 10 points, and the higher the score, the better the performance.

[0070] The standard sample used for quality evaluation was food-grade natural L-menthol produced by Anhui Fengle Spice Co., Ltd.

[0071] The specific scoring process is as follows:

[0072] The jury is composed of 5 judges with the qualification of second-level perfumer. The jury is responsible for evaluating and scoring the samples. After the scoring is completed, the average score is taken as the final score of the test sample.

[0073] Odor evaluation method: In an aroma evaluation room with fresh air and no impurities, select standard samples and samples to be tested, crush them separately and place them in the same, clean and odorless container to evaluate the purity of the odor. The evaluation results are expressed as scores. The higher the score, the closer the odor is to the standard sample. The scoring levels are as follows: pure (9.1 points-10.0 points), relatively pure (8.1 points-9.0 points), acceptable (7.1 points-8.0 points), fair (6.1 points-7.0 points), passing (5.0 points-6.0 points), and failing (below 5.0 points).

[0074] Evaluation method for coolness and transparency: The standard sample and the sample to be tested are diluted with a solvent (bisaldehyde alcohol) to a concentration of 1wt%, and then applied to the inner side of the elbow joints of the assessors on both sides. Scores are given based on the degree of coolness. The higher the score, the closer the coolness feeling is to the standard sample. The scoring levels are as follows: transparent (9.1-10 points), relatively transparent (8.1-9.0 points), acceptable (7.1-8.0 points), fair (6.1-7.0 points), passing (5.0-6.0 points), and failing (below 5.0 points).

[0075] The evaluation results are shown in Table 2 below:

[0076] Table 2

[0077] As can be seen from the experimental results in Tables 1 and 2, the method of the present invention can significantly improve the odor purity and cooling penetration of the L-menthol product by aging the L-menthol, controlling the average particle size L of the L-menthol to be treated, the thickness D of the L-menthol material layer, and the aging temperature T and time t within specific ranges and satisfying the relationship requirements of the present invention.

[0078] In Comparative Example 1, the thickness D of the L-menthol material layer of the L-menthol to be processed was not within the range required by the present invention. Although aging was performed, it was difficult to obtain a high-quality L-menthol product.

[0079] In Comparative Example 2, the average particle size L of the L-menthol to be processed, the thickness D of the L-menthol material layer, the temperature T and time t of the aging treatment were not simultaneously controlled within the specific ranges, and these four conditions did not satisfy the relationship requirements of the present invention. It was also difficult to obtain a high-quality L-menthol product through the aging treatment.

[0080] It will be readily understood that the above embodiments are merely examples for clarity of description and are not intended to limit the present invention to these examples. Those skilled in the art will readily appreciate that other variations or modifications based on the above description are possible. It is not necessary and impossible to provide an exhaustive list of all possible implementations. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for improving the quality of L-menthol products, characterized in that: The method comprises the following steps: The L-menthol to be treated is laid to form an L-menthol material layer, and then subjected to a aging treatment, and the aging treatment must simultaneously meet the following conditions: The average particle size L of the L-menthol to be treated is 0.5-2 cm, the thickness D of the L-menthol material layer is 1-50 cm, the temperature T of the aging treatment is 10-50° C., the time t of the aging treatment is 0.1-24 h, and the L, the D, the T, and the t need to satisfy the following relationship:

2. The method according to claim 1, characterized in that The average particle size L of the L-menthol to be treated is 0.5-1.5 cm.

3. The method according to claim 1, characterized in that The thickness D of the L-menthol material layer is 1-10 cm.

4. The method according to claim 1, characterized in that The temperature T of the aging treatment is 20-40°C.

5. The method according to any one of claims 1 to 4, characterized in that: The time t of the aging treatment is 1-12h.

6. The method according to claim 1, characterized in that The average particle size L of the L-menthol to be treated is 0.5-1.5 cm, the thickness D of the L-menthol material layer is 1-10 cm, the temperature T of the aging treatment is 20-40° C., and the time t of the aging treatment is 1-12 h.

7. The method according to any one of claims 1 to 4 or 6, characterized in that: The L-menthol to be treated is formed L-menthol; Preferably, the molded L-menthol is in the form of flakes, blocks or spheres.

8. The method according to any one of claims 1 to 4 or 6, characterized in that: The chemical purity of the L-menthol to be treated is >95 wt%.

9. The method according to claim 8, characterized in that The chemical purity of the L-menthol to be treated is >99 wt%.

10. The method according to any one of claims 1 to 4 or 6, characterized in that: The equipment used for the aging treatment is a box-type, kettle-type, crawler-type or plate-type equipment.

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