A method for improving heat resistance and fragrance retention of garlic essential oil

Abstract

The invention provides a method for improving the heat resistance and aroma retention of garlic essential oil, and relates to the technical field of chemical processing. The method comprises the following steps: peeling, washing, crushing, enzymolysis, distillation, condensation, and oil-water separation of garlic to obtain garlic essential oil, and then adding vitamin C ethyl ether, and heating and reacting under sealed conditions to obtain garlic essential oil with improved heat resistance and aroma retention; the garlic essential oil obtained after the treatment by the method of the invention has a significantly improved concentration of sulfide, a characteristic flavor substance, and a significantly improved thermal stability and aroma retention; therefore, in applications such as food processing and biomedicine, the amount of garlic essential oil used can be reduced by about 30% to 50%, and the use cost is reduced, which has a good market prospect.

Description

Technical Field

[0001] The invention relates to the field of chemical processing, in particular to a method for improving the heat resistance and fragrance retention of garlic essential oil. Background Art

[0002] Garlic is the underground bulb of the Allium plant of the Liliaceae family. It is a common vegetable and condiment with medical and health value, and is known as a "natural broad-spectrum antibiotic". Studies have shown that the main active ingredient of garlic is garlic essential oil, which was obtained by German chemist Wertheim in 1844 by steam distilling crushed garlic to obtain a volatile oily substance with a strong odor. Garlic essential oil is the general name for all sulfur-containing compounds in garlic. It is a bright, transparent amber liquid. This essential oil has a strong garlic aroma, which can significantly enhance the flavor of food and increase appetite. It is widely used in the field of food processing; at the same time, it contains very important active sulfides. Because of its strong antibacterial and anti-inflammatory effects and health-care effects, it has an inhibitory and killing effect on Gram-positive bacteria, Gram-negative bacteria and a variety of pathogenic bacteria. It is widely used in the field of food preservation and has good effects in lowering blood pressure, lowering blood lipids, inhibiting platelet aggregation, preventing cancer, enhancing immunity, and delaying aging. The development of garlic essential oil not only has good commercial value, but also has a positive role in increasing farmers' income.

[0003] Under normal temperature and pressure, well-preserved garlic bulb cells contain alliin, and the cell walls contain endogenous alliinase. When the tissue cells of garlic cloves are damaged, alliinase can act on alliin in a water environment, causing enzymatic hydrolysis of alliin. Under the action of a thermal environment, alliin is then converted into a series of volatile active sulfides, such as diallyl sulfide, diallyl disulfide, diallyl trisulfide, and diallyl tetrasulfide. These sulfides are also the main characteristic flavor substances in garlic, with a strong garlic aroma, and contribute greatly to the flavor of garlic essential oil. They are often used as indicators for the quality control of garlic essential oil. The quality of garlic essential oil directly affects key issues such as the economic benefits and healthy development of enterprises.

[0004] At present, the main methods for extracting garlic essential oil include water distillation extraction, organic solvent extraction, microwave-assisted organic solvent extraction, supercritical CO2 extraction, etc.; the yield of garlic essential oil obtained by organic solvent extraction is relatively high, but there are many soluble impurities in it, and further purification is difficult, and some organic solvents are highly toxic, and their residual amount is difficult to control, so it is not easy to obtain high-quality garlic essential oil, and the solvent is easy to leak and pollute the environment, which is not suitable for industrial production; the extraction rate of microwave-assisted organic solvent extraction is generally low; supercritical CO2 extraction can quickly extract high-boiling point substances, and avoid solvent residues caused by solvent extraction, improve the quality and appearance of the product, and in the production process There is no emission of toxic and harmful substances and no impact on the environment, but the equipment investment required is large, the industrialization cost is high, the difficulty is great, and the production efficiency is relatively low; the steam distillation method has high oil purity, simple equipment requirements, convenient operation, low cost, easy promotion, strong practicality, green and environmental protection, and no organic residue. It is a better method for extracting garlic essential oil, but the problem of this method is that the extracted garlic essential oil is not heat-resistant and sensitive to the environment. The flavor-active sulfide therein is easy to decompose and the fragrance is not easy to retain, which is not conducive to the stable storage and use of the effective ingredients of garlic essential oil. How to produce garlic essential oil with better quality and more stable quality at a lower cost is a problem that needs to be solved urgently.

[0005] Vitamin C ethyl ether is a vitamin C derivative. It is not only very stable in chemical properties, light-resistant, heat-resistant, acid-resistant, alkali-resistant, salt-resistant, and has strong antioxidant properties, but it is also a hydrophilic and lipophilic substance, which greatly broadens its application areas, especially in daily chemical applications. Vitamin C ethyl ether can easily pass through the stratum corneum into the dermis. After entering the body, it is very easy to be decomposed by the biological enzymes in the body to exert the biological effects of vitamin C. Summary of the invention

[0006] In order to solve the problems of heat resistance and fragrance retention of garlic essential oil and obtain garlic essential oil with good quality and stability, the present invention provides a method for improving the heat resistance and fragrance retention of garlic essential oil. The method comprises the following steps: after the garlic essential oil is obtained by distillation, vitamin C ethyl ether is added to the garlic essential oil, the mixture is stirred evenly, and the mixture is subjected to a sealed circulation reflux reaction for 2 to 3 hours under the conditions of a pressure of 1.2 to 1.5 atm and a temperature of 110 to 120° C., so as to obtain garlic essential oil with improved heat resistance and fragrance retention.

[0007] The preparation method of the garlic essential oil comprises the following steps: mixing garlic paste and distilled water, adding 1-3% of cellulase according to the mass ratio of the garlic paste, and performing enzymolysis for 2-4 hours under a constant temperature condition of 32-45°C; introducing water vapor after the enzymolysis, distilling the enzymolyzed garlic paste for 2-3 hours, condensing, and separating and extracting the garlic essential oil.

[0008] The preparation method of the mashed garlic comprises the following steps: peeling and cleaning the garlic, adding distilled water, and crushing and homogenizing the garlic into the mashed garlic.

[0009] Wherein, the solid-liquid ratio of the garlic to distilled water is 1:2 to 1:4.

[0010] Wherein, the added amount of the vitamin C ethyl ether is 1.0 to 1.8‰.

[0011] Beneficial Effects

[0012] The invention provides a method for improving the heat resistance and lasting fragrance of garlic essential oil. The method is simple to operate. Specifically, vitamin C ethyl ether is added to the garlic essential oil, stirred evenly, and sealed and circulated for reflux reaction for 2 to 3 hours under the conditions of pressure of 1.2 to 1.5 atm and temperature of 110 to 120° C., so as to obtain the garlic essential oil with heat resistance and lasting fragrance. The inventors conducted mass spectrometry analysis on the garlic essential oil obtained by not adding vitamin C ethyl ether, stirring evenly, and sealing and circulated for reflux reaction under the conditions of pressure of 1.2 to 1.5 atm and temperature of 110 to 120° C. (Comparative Example 3) and the garlic essential oil obtained by Example 1. The results show that after the reaction of vitamin C ethyl ether and garlic essential oil, the garlic essential oil The content of diallyl tetrasulfide, an effective flavor active ingredient, has been significantly increased, and the thermal stability of its flavor substances has been significantly improved. The possible reason is that after the addition of vitamin C ethyl ether, under high temperature and high pressure environment, vitamin C ethyl ether can provide certain hydrogen bonds to undergo cross-linking reactions with sulfur-containing compounds, converting unstable diallyl disulfide into stable and long-lasting diallyl tetrasulfide, and forming a stable structural system, which improves heat resistance and avoids further decomposition of these characteristic flavor sulfides; at the same time, vitamin C ethyl ether may cause some non-characteristic flavor substances to react and transform into characteristic flavor sulfides, thereby increasing the content of some characteristic flavor sulfides; in addition, vitamin C ethyl ether can make the main aroma of sulfides more lasting. Judging from the results of GC-MS, there are 4 more components in the mixed garlic essential oil after the reaction, two of which are unknown components, which may be related to vitamin C ethyl ether. Further testing is needed for the specific details. No other toxic and harmful substances have been found to be formed in the whole system. Therefore, the whole treatment method is safe and reliable. The whole reaction makes the garlic essential oil product have a stable and high concentration of effective ingredients without changing the quality of the garlic essential oil. The fragrance is rich and lasting. In applications such as food processing and biomedicine, its usage can be reduced by about 30% to 50%. After component analysis and toxicological analysis, it can be widely used in garlic-flavored food additives to increase the durability of garlic flavor essence and reduce its usage, thereby reducing its cost of use. It has a good market prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is the flow chart of garlic essential oil distillation and extraction equipment.

[0014] Figure 2 The mass spectra of the garlic essential oils of Example 3 and Comparative Example 3 (Wang Hui No. 1 is Example 3, and Wang Hui No. 2 is Comparative Example 3).

[0015] Figure 3 This is the GC-MS analysis chart of peaks 1 to 4 of Example 3.

[0016] Figure 4 This is the GC-MS analysis chart of peaks 5 to 8 in Example 3.

[0017] Figure 5 This is the GC-MS analysis chart of peaks 9 to 12 in Example 3.

[0018] Figure 6 This is the GC-MS analysis chart of peaks 13 to 16 in Example 3.

[0019] Figure 7 This is the GC-MS analysis chart of peaks 17 to 20 in Example 3.

[0020] Figure 8 This is the GC-MS analysis chart of peaks 21 to 24 of Example 3.

[0021] Fig. 9 This is the GC-MS analysis chart of peaks 1 to 4 of control group 3.

[0022] Fig.10 This is the GC-MS analysis chart of peaks 5 to 8 of control group 3.

[0023] Fig.11 This is the GC-MS analysis chart of peaks 9 to 12 of control group 3.

[0024] Fig.12 This is the GC-MS analysis chart of peaks 13 to 16 of control group 3.

[0025] Fig.13 This is the GC-MS analysis chart of peaks 17 to 20 of control group 3. DETAILED DESCRIPTION

[0026] Garlic was purchased from Zhougudui Wholesale Market in Hefei, vitamin C ethyl ether was purchased from Anhui Lurong Biotechnology Co., Ltd. (food grade); cellulase (food grade) was purchased from Henan Wanbang Chemical Technology Co., Ltd.

[0027] The active sulfide in garlic essential oil is qualitatively and quantitatively detected by GC / MS, and the content change is reflected by comparing and analyzing the total peak area (%) data of each component in the mass spectrum.

[0028] Example 1

[0029] 1. Pre-distillation treatment process: peel and wash the garlic, add distilled water, the material-liquid ratio of garlic to distilled water is 1:2, put it in a crusher, crush and homogenize it into garlic paste; based on the garlic paste, add 1% cellulase according to the mass fraction, and place it in a water bath with a constant temperature water bath at 45°C for 2 hours.

[0030] 2. Distillation extraction: transfer the pre-treated garlic paste to a distillation device, pass water vapor, distill the enzymatically hydrolyzed garlic paste for 2 hours, pass the distilled water vapor containing garlic essential oil into a condensation device, collect, separate and extract the garlic essential oil.

[0031] 3. Post-distillation treatment process: add 1.0‰ vitamin C ethyl ether to the garlic essential oil, stir evenly, inject into a sealed tank, control the pressure to 1.5atm, control the temperature to 120°C, react in the sealed tank circulation reflux pipe for 2h to obtain the garlic essential oil.

[0032] Embodiment 2:

[0033] 1. Pre-distillation treatment process: Peel and wash the garlic, add distilled water, the material-liquid ratio of garlic to distilled water is

[0034] 1:3, placed in a crusher, crushed and homogenized into garlic paste; based on the garlic paste, add 3% cellulase according to the mass fraction, and placed in a water bath with a constant temperature water bath temperature of 32°C for 4 hours.

[0035] 2. Distillation extraction: transfer the pre-treated garlic paste to a distillation device, pass water vapor, distill the enzymatically hydrolyzed garlic paste for 2.5 hours, pass the distilled water vapor containing garlic essential oil into a condensation device, collect, separate and extract the garlic essential oil.

[0036] 3. Post-distillation treatment process: add 1.5‰ vitamin C ethyl ether to the garlic essential oil, stir evenly, inject into a sealed tank, control the pressure to 1.3atm, control the temperature to 115°C, react in the sealed tank circulation reflux pipe for 2.5h to obtain the garlic essential oil.

[0037] Embodiment 3:

[0038] 1. Pre-distillation treatment process: peel and wash the garlic, add distilled water, the material-liquid ratio of garlic to distilled water is 1:4, put it in a crusher, crush and homogenize it into garlic paste; based on the garlic paste, add 1% cellulase according to the mass fraction, and place it in a water bath with a constant temperature water bath at 38°C for 3 hours.

[0039] 2. Distillation extraction: transfer the pre-treated garlic paste to a distillation device, pass water vapor, distill the enzymatically hydrolyzed garlic paste for 3 hours, pass the distilled water vapor containing garlic essential oil into a condensation device, collect, separate and extract the garlic essential oil.

[0040] 3. Post-distillation treatment process: add 1.8‰ vitamin C ethyl ether to the garlic essential oil, stir evenly, inject into a sealed tank, control the pressure to 1.2atm, control the temperature to 110°C, react in the sealed tank circulation reflux pipe for 3h to obtain the garlic essential oil.

[0041] Comparison example:

[0042] Control group 1: In the post-distillation treatment process, vitamin C ethyl ether was not added, and the other steps were the same as those in Example 3.

[0043] Control group 2: In the post-distillation treatment process, only 1.8‰ vitamin C ethyl ether was added without heating reaction, and the other steps were the same as those in Example 3.

[0044] Control group 3: the sample without post-distillation treatment, i.e., the garlic essential oil extracted in step 2 of Example.

[0045] Experimental results:

[0046] From Tables 1 and 2, Figures 2 to 13 It can be seen that compared with the control group 3, the garlic essential oil extracted in the embodiment 3 group, the contents of the characteristic flavor active sulfides diallyl sulfide, diallyl trisulfide and diallyl tetrasulfide are all increased, wherein the content of diallyl tetrasulfide is increased from 2% to 6%, which is significantly increased, while the content of diallyl disulfide is significantly decreased. The reason for this may be that after the addition of vitamin C ethyl ether, under high temperature and high pressure environment, vitamin C ethyl ether can provide certain hydrogen bonds to react with sulfur-containing compounds to undergo cross-linking reactions, converting unstable diallyl disulfide into stable and durable diallyl tetrasulfide, and forming a stable structural system, thereby improving heat resistance and avoiding further decomposition of these characteristic flavor sulfides; at the same time, vitamin C ethyl ether may cause some non-characteristic flavor substances to react and transform into characteristic flavor sulfides, thereby increasing the content of some characteristic flavor sulfides; in addition, vitamin C ethyl ether may have good aroma holding and fixing effects, which can make the main aroma of sulfides more durable. Judging from the results of GC-MS, there are 4 more components in the mixed essential oil after the reaction, two of which are unknown components, which may be related to vitamin C ethyl ether. Further testing is needed. No other toxic or harmful substances have been found in the entire system. Therefore, the entire treatment method is safe and reliable.

[0047] Table 1: Garlic essential oil component analysis table obtained in step 3 of Example 3

[0048]

[0049] Table 2 Comparative Example 3 Garlic essential oil composition analysis after treatment

[0050]

[0051] Table 3, table of the contents of four active sulfides in the embodiments and comparative examples

[0052]

[0053] The applicant conducted a persistence experiment on the garlic essential oils prepared in Examples 1 to 3 and Control Groups 1 to 3. Equal amounts of garlic essential oils of the experimental group and the control group were dipped into scented paper and placed at room temperature for 48 hours. Three people smelled the scented paper every 12 hours and recorded the smells. The experimental results showed that at 24 hours, the experimental group had a strong garlic aroma, while the control group had almost no garlic aroma. The specific sensory evaluation table is as follows.

[0054] Table 3, Storage sensory evaluation table of embodiments and comparative examples

[0055] Time (h) 12 24 36 48 Example 1 Strong and pungent garlic aroma Strong garlic aroma Light garlic aroma Can smell garlic aroma Example 2 Strong and pungent garlic aroma Strong garlic aroma Light garlic aroma Can smell garlic aroma Example 3 Strong and pungent garlic aroma Strong garlic aroma Light garlic aroma Can smell garlic aroma Control group 1 Light garlic aroma Almost no garlic smell No smell of garlic No smell of garlic Control group 2 Light garlic aroma Almost no garlic smell No smell of garlic No smell of garlic Control group 3 Light garlic aroma Almost no garlic smell No smell of garlic No smell of garlic

Claims

1. A method for improving the heat resistance and fragrance retention of garlic essential oil, characterized in that: The specific method is to add 1.0-1.8‰ vitamin C ethyl ether to the garlic essential oil after the distillation is completed, stir evenly, and perform a sealed circulation reflux reaction for 2-3 hours under the conditions of a pressure of 1.2-1.5 atm and a temperature of 110-120°C to obtain garlic essential oil with increased heat resistance and lasting fragrance.

2. The method for improving the heat resistance and fragrance retention of garlic essential oil according to claim 1, characterized in that: The preparation method of the garlic essential oil comprises the following steps: mixing garlic paste and distilled water, adding 1-3% of cellulase according to the mass ratio of the garlic paste, and performing enzymolysis for 2-4 hours under a constant temperature condition of 32-45° C.; introducing water vapor after the enzymolysis, distilling the enzymolyzed garlic paste for 2-3 hours, condensing, and separating and extracting the garlic essential oil.

3. The method for improving the heat resistance and fragrance retention of garlic essential oil according to claim 2, characterized in that, The preparation method of the garlic paste is as follows: peeling and cleaning the garlic, adding distilled water, and crushing and homogenizing the garlic into the garlic paste.

4. The method for improving the heat resistance and fragrance retention of garlic essential oil according to claim 3, characterized in that: The solid-liquid ratio of the garlic to distilled water is 1:2 to 1:4.

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