Method for detecting flavor of pepper essential oil

Abstract

The invention discloses a pepper essential oil flavor detection method. The method comprises the following steps: S1, raw material pretreatment: collecting fresh pepper leaves, and controlling the moisture to be 10-20%; s2, steam distillation: heating distilled water, and distilling the zanthoxylum bungeanum leaves by using steam; s3, separation: carrying out oil-water separation on water distilled in the step S2 by using an oil-water separator, and collecting essential oil; s4, GC-MS (gas chromatography-mass spectrometry) detection: detecting the content of volatile compounds in the essential oil collected in the step S3 by adopting a gas chromatography-mass spectrometry method. According to the method, steam distillation is adopted, extra solvent extraction is not needed, experimental raw materials are purely natural and free of pollution, experimental equipment is simple, operation is easy and convenient, various flavor substances exist, and the applicability is wide.

Description

Technical Field

[0001] The invention belongs to the field of detection technology, and particularly relates to a method for detecting the flavor of Zanthoxylum bungeanum essential oil. Background Art

[0002] Zanthoxylum bungeanum essential oil is typically found in the leaves and fruits of Zanthoxylum bungeanum, emitting an aromatic aroma. It is unstable and volatile under oxygen, light, and high temperature conditions. Its main components are aliphatic, aromatic, and fungi-based compounds. These compounds also include their oxygen-containing derivatives, such as alcohols, aldehydes, ketones, acids, and esters, as well as nitrogen- and sulfur-containing compounds. While research on Zanthoxylum bungeanum fruits is extensive, research on Zanthoxylum bungeanum leaves is relatively limited. The main extraction methods for Zanthoxylum bungeanum essential oil from Zanthoxylum bungeanum fruits and leaves include steam distillation and solvent extraction. Steam distillation utilizes the fact that volatile substances are insoluble or slightly soluble in water and do not react azeotropically with water. The volatile substances are then distilled by directly adding water and then heating or by introducing steam. The water and Zanthoxylum bungeanum essential oil mixture is then recovered through a condenser. The essential oil can then be separated from the mixture by using an oil-water separator or by extraction with anhydrous ether followed by rotary evaporation. The solvent extraction method extracts the target substance according to the different solubility of the substance in different solvents to form a mixed solution, and then the target substance can be obtained by rotary evaporation.

[0003] Luo Kai et al., using steam distillation to extract essential oil from Zanthoxylum bungeanum, found that the extraction yield was only 6.66%, indicating a high loss of essential oil during steam distillation. The degree of crushing of the Zanthoxylum bungeanum can affect the extraction yield. Luo Yihua et al., analyzing the crushing degree during steam distillation of Zanthoxylum bungeanum essential oil, found that the yield increased when the crushing degree was between 20 and 40 mesh, but the yield was actually lower at a crushing degree of 50 mesh compared to a crushing degree of 40 mesh. This may be due to the small size of the Zanthoxylum bungeanum powder, which formed a sticky paste with the steam. Solvent extraction, based on the different solubility properties of a substance in different solvents, extracts the target substance to form a mixed solution, which is then obtained through rotary evaporation. Luo Kai et al. achieved an extraction yield of 8.37% using solvent extraction, indicating a low loss of essential oil, but with a significant loss of essential oil species, only 17 substances were identified. Zhao Zhifeng et al. studied Zanthoxylum bungeanum (Zanthoxylum bungeanum) from Hanyuan, Sichuan, using anhydrous ethanol, ether, acetone, and distilled water as solvents for solvent extraction. They found that the color, state, and odor of Zanthoxylum bungeanum essential oil extracted with different solvents varied, and that organic solvents were far more effective than water. Ether, in particular, achieved the highest extraction rate of Zanthoxylum bungeanum essential oil components. Song Rong et al. used Zanthoxylum bungeanum from Dezhou, Shandong, using petroleum ether, ether, dichloromethane, and ethanol as solvents for extraction, finding that petroleum ether and ether had the highest extraction rates.

[0004] The solvent extraction method will cause solvent residue and is too costly, and the product appearance is dark in color. Steam distillation has good flavor properties, but its extraction rate is low. Currently, there is no simple and rapid method on the market to detect the flavor properties of Sichuan pepper leaves after they are made into Sichuan pepper essential oil.

[0005] Currently, the primary method for determining the volatility of Zanthoxylum bungeanum essential oil is gas chromatography-mass spectrometry (GC-MS). While both GC-MS and GC-IMS are highly sensitive for detecting trace substances, the high volatility of Zanthoxylum bungeanum essential oil presents challenges in both quantitative and qualitative analysis. For example, the sheer number of peaks can be difficult to accurately distinguish, and the large areas of some peaks can mask other substances.

[0006] Therefore, a method for detecting the flavor of Zanthoxylum bungeanum essential oil is in urgent need of proposal. Summary of the Invention

[0007] In order to solve the defects of the prior art, the present invention provides a method for detecting the flavor of Zanthoxylum bungeanum essential oil.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0009] The present invention provides a method for detecting the flavor of Zanthoxylum bungeanum essential oil, comprising the following steps:

[0010] S1. Raw material pretreatment: After collecting fresh Zanthoxylum bungeanum leaves, control the moisture content to 10%-20%;

[0011] S2, steam distillation: heating distilled water and using steam to distill the Zanthoxylum bungeanum leaves;

[0012] S3, separation: using an oil-water separator to separate the water distilled in step S2 into oil and water, and collecting the essential oil;

[0013] S4. GC-MS detection: Gas chromatography-mass spectrometry is used to detect the content of volatile compounds in the essential oil collected in step S3.

[0014] Preferably, the gas chromatography conditions in step S4 are as follows: an Agilent HP-5 19091J-413 gas chromatography column, an inlet temperature of 270°C, helium as the carrier gas, a flow rate of 1.3 mL / min, a split injection ratio of 75:1, and a solvent delay of 3 min.

[0015] Preferably, the temperature rising process in the gas chromatography conditions is as follows: the initial temperature is maintained at 40°C for 1 minute, the temperature is raised to 170°C at a rate of 3°C / min, and finally the temperature is raised to 270°C at a rate of 8°C / min and maintained for 5 minutes.

[0016] Preferably, the mass spectrometry conditions in step S4 are: EI ion source, electron energy 70 eV, ion source temperature 230° C., quadrupole temperature 150° C., and collection mass range 35-550 m / z.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The invention uses steam distillation, eliminating the need for additional solvent extraction. The experimental raw materials are pure natural and pollution-free, and the experimental equipment is simple and easy to operate. The invention also contains a wide variety of flavor compounds and has wide applicability. Controlling the moisture content of fresh Zanthoxylum bungeanum leaves after collection can change the initial form of the raw materials, facilitating subsequent experiments and increasing the oil extraction rate. Furthermore, the residue after the experiment is minimal, making it easier to clean the experimental equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the GC-MS ion chromatogram in Example 1 of the present invention; from top to bottom, they are red pepper leaf essential oil and green pepper leaf essential oil;

[0020] Figure 2 Schematic diagram of the structure of the distillation apparatus in Example 1 of the present invention. DETAILED DESCRIPTION

[0021] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0022] Example 1

[0023] Take two different types of fresh Zanthoxylum bungeanum leaves (red and green) (both from Hubei Mingchuang Agricultural Science and Technology Development Co., Ltd.), control the moisture content to 20% after collection, and do not crush. Assemble the spherical condenser, 1000ml beaker, 1000ml solvent ball, oil-water separator, two-port connecting pipe, and electric heating furnace ( Figure 2 The distillation apparatus is from Wuhan Xinshenshi Chemical Technology Co., Ltd. Place Zanthoxylum bungeanum leaves in a 1000ml solvent bulb. Add 600ml of distilled water to a 1000ml flask. After assembling the apparatus, turn on the electric furnace. Use an oil-water separator to continuously drain the lower layer of water. After two hours, turn off the electric furnace and collect the essential oil from the lower layer using the oil-water separator.

[0024] GC-MS detection: Gas chromatography conditions were as follows: an Agilent HP-5 19091J-413 gas chromatographic column was used, the inlet temperature was 270°C, the carrier gas was helium, the flow rate was maintained at 1.3 mL / min, the split injection was 75:1, and the solvent delay was 3 min.

[0025] Heating process: Initial temperature 40℃, maintained for 1 min, then heated to 170℃ at 3℃ / min, and finally heated to 270℃ at 8℃ / min, maintained for 5 min (the change in heating technology will lead to better peak separation and more volatile substances will be detected).

[0026] The mass spectrometry conditions were as follows: EI ion source, electron energy 70 eV, ion source temperature 230 °C, quadrupole temperature 150 °C, and collection mass range 35–550 m / z.

[0027] After testing, the extraction rate of essential oil from Zanthoxylum bungeanum leaves was 0.5%, with good odor properties and transparent and shiny appearance. GC-MS detected a total of 121 volatile compounds ( Figure 1 ), including 71 red and 69 green Zanthoxylum bungeanum species, encompassing numerous volatile aroma components with high separation between the substances, numerous Gaussian peaks, and baseline separation. Controlling moisture content after collecting fresh Zanthoxylum bungeanum leaves can alter the initial form of the raw material, facilitating subsequent experiments and increasing oil extraction rates. Post-experimental residue is minimal, making cleaning of experimental equipment easier.

[0028] Table 1: Test results of red and green pepper.

[0029]

[0030]

[0031]

[0032]

[0033] RI 1 : Actual calculation of retention index, RI 2 : Relevant retention indices found through NIST Chemistry WebBook.

[0034] Qualitative analysis: Qualitative analysis was performed using the NIST11 spectral library search combined with retention index. Quantitative analysis: For each compound to be quantified, 2-methyl-3-heptanone was selected as the internal standard and quantified by the internal standard method.

[0035]

[0036] Among them, A and A i Represent the peak areas of the compound and internal standard, respectively. C (ug / mL) and C i (ug / mL) represents the mass concentration of the compound and internal standard, respectively.

[0037] The retention index is calculated using C7-C40 normal alkanes as the standard according to the following formula:

[0038]

[0039] Among them, X i represents the retention time of the compound to be analyzed (min), X n Indicates the retention time (min) of the nearest normal alkane before the appearance of the compound to be analyzed, X n+1 Indicates the retention time (min) of the nearest n-alkane after the appearance of the compound to be analyzed.

[0040] Example 2

[0041] The rest is the same as Example 1, except that, in this embodiment, the moisture content of fresh Zanthoxylum bungeanum leaves of green and red Zanthoxylum bungeanum leaves is controlled to 10% after being collected, and they are not crushed.

[0042] Example 3

[0043] The rest is the same as Example 1, except that, in this embodiment, the moisture content of fresh Zanthoxylum bungeanum leaves of green and red Zanthoxylum bungeanum leaves is controlled to 15% after being collected, and they are not crushed.

[0044] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for detecting the flavor of Zanthoxylum bungeanum essential oil, characterized in that: The following steps are involved: S1. Raw material pretreatment: After collecting fresh Zanthoxylum bungeanum leaves, control the moisture content to 10%-20%; S2, steam distillation: heating distilled water and using steam to distill the Zanthoxylum bungeanum leaves; S3, separation: using an oil-water separator to separate the water distilled in step S2 into oil and water, and collecting the essential oil; S4. GC-MS detection: Gas chromatography-mass spectrometry is used to detect the content of volatile compounds in the essential oil collected in step S3.

2. A method for detecting the flavor of Zanthoxylum bungeanum essential oil according to claim 1, characterized in that: The gas chromatography conditions in step S4 are as follows: an Agilent HP-5 19091J-413 gas chromatography column is used, the injection port temperature is 270°C, the carrier gas is helium, the flow rate is maintained at 1.3 mL / min, the split injection is 75:1, and the solvent delay is 3 min.

3. A method for detecting the flavor of Zanthoxylum bungeanum essential oil according to claim 2, characterized in that, The temperature rise process in the gas chromatography conditions is as follows: the initial temperature is 40°C, maintained for 1 min, raised to 170°C at 3°C / min, and finally raised to 270°C at 8°C / min and maintained for 5 min.

4. A method for detecting the flavor of Zanthoxylum bungeanum essential oil according to claim 1, characterized in that: The mass spectrometry conditions in step S4 are as follows: EI ion source, electron energy 70 eV, ion source temperature 230°C, quadrupole temperature 150°C, and collection mass range 35-550 m / z.

Images