Method for preparing black garlic stock solution by supercritical carbon dioxide extraction

Abstract

The present application provides a method for preparing black garlic stock solution by supercritical carbon dioxide extraction, which includes: (1) black garlic pretreatment; and (2) supercritical carbon dioxide extraction, wherein an entrainer and a surfactant are used in the supercritical carbon dioxide extraction. By reasonably designing the parameters of the supercritical carbon dioxide extraction and the types and dosages of the entrainer and the surfactant used therein, the method of the present application effectively improves the extraction rates of active ingredients such as allicin, alliin, and deoxyalliin.

Description

Technical Field

[0001] This application belongs to the field of natural product extraction. Specifically, this application provides a method for preparing black garlic stock solution by supercritical carbon dioxide extraction. Background Art

[0002] Black garlic is a processed food made from garlic, which reduces the pungent taste and smell of garlic and optimizes the taste and nutrition, and has gradually become popular in recent years. Black garlic contains rich proteins / amino acids, polysaccharides, and trace elements; allicin in it has significant bactericidal and anti-inflammatory effects; polyphenol and superoxide dismutase components can provide significant antioxidant effects; alliin components, such as alliin and deoxyalliin, have definite anti-tumor and immune regulation effects.

[0003] Although the taste of black garlic has been improved compared with that of garlic, for a large part of people, the obstacle of direct consumption is still relatively large, and extracting the active ingredients in it can effectively solve this problem. After researching various extraction methods (Journal of Shandong University, Engineering Science Edition, Vol. 37, No. 5), it is generally considered that the supercritical carbon dioxide extraction method is an ideal method for extracting garlic stock solution products at present. The components in the extracted products are rich, and various volatile and non-volatile components can be retained to a great extent. However, there is no relevant research record for black garlic.

[0004] Therefore, developing a supercritical carbon dioxide extraction method suitable for black garlic to prepare an extract that retains the active ingredients of black garlic to the greatest extent is very valuable for the development and utilization of black garlic. Summary of the Invention

[0005] In view of the above problems, the applicant mainly considered allicin, alliin, and polyphenol components, and studied and improved the supercritical carbon dioxide extraction method for black garlic.

[0006] On the one hand, this application provides a method for preparing black garlic stock solution by supercritical carbon dioxide extraction, and the method includes:

[0007] (1) Pretreatment of black garlic;

[0008] (2) Supercritical carbon dioxide extraction, wherein an entrainer and a surfactant are used.

[0009] Further, step (1) is to peel, chop, freeze-dry, and pulverize black garlic, and then pass through a 50-200 mesh sieve to obtain black garlic freeze-dried powder.

[0010] Further, the conditions for supercritical carbon dioxide extraction in step (2) are an extraction temperature of 30°C, an extraction pressure of 30 MPa, a carbon dioxide flow rate of 25 L / h, and an extraction time of 1.5 h.

[0011] Further, the entrainer is an aqueous ethanol solution of 50-90% v / v.

[0012] Further, the surfactant is sodium dodecyl sulfate or monoglyceryl succinate.

[0013] Further, the surfactant is sodium dodecyl sulfate, and the dosage is 2% of the mass of the black garlic freeze-dried powder.

[0014] Further, step (2) is to add the black garlic freeze-dried powder obtained in step (1) and monoglyceryl succinate of 2.5% of the mass of the black garlic freeze-dried powder into an aqueous ethanol solution of 60% v / v with a mass three times that of the black garlic freeze-dried powder, and prepare black garlic stock solution by supercritical carbon dioxide extraction after mixing. The conditions for supercritical carbon dioxide extraction are extraction temperature 30°C, extraction pressure 30 MPa, carbon dioxide flow rate 25 L / h, and extraction time 1.5 h.

[0015] Further, step (1) is to peel, chop, freeze-dry, and pulverize black garlic, and then pass through a 100-mesh sieve to obtain black garlic freeze-dried powder.

[0016] Further, the black garlic is black garlic prepared from Cangshan garlic as the raw material.

[0017] Based on the similarity of the basic components of garlic, the method of the present application can be appropriately modified and used for black garlic products prepared from various garlic varieties, including but not limited to Soviet garlic, soft-leaf garlic, Puning garlic, etc.

[0018] On the other hand, the present application provides a black garlic stock solution prepared by the above method.

[0019] By reasonably designing the parameters of supercritical carbon dioxide extraction and the types and dosages of entrainers and surfactants used therein, the method of the present application effectively improves the extraction rates of key active ingredients in black garlic products such as allicin, alliin, and deoxyalliin, providing a good basis for the preparation of black garlic health products, drugs, etc. Description of the Drawings

[0020] Figure 1 Shows the influence of ethanol entrainers with different concentrations on the extraction rates of alliin / deoxyalliin. Detailed Description of the Embodiments

[0021] Main Equipment and Methods in Example 1

[0022] Supercritical Carbon Dioxide Extractor:

[0023] Shi Anjia, BA-CQ24D;

[0024] Black Garlic Product:

[0025] The applicant prepared the same batch of products with Cangshan garlic as the raw material by the solid fermentation method. After measurement, the reducing sugar content of this batch of products was 39.2 - 40.5% by weight, the total phenol content was 8.1 - 8.3‰ by weight, the total content of alliin and alliinase was 13.3 - 14.1‰ by weight, and the allicin content was 4.6 - 5.4‰ by weight.

[0026] Ethanol, Tween, Span, monoglyceride succinate, polyglycerol fatty acid ester, sucrose fatty acid ester, and sodium dodecyl sulfate are all domestic food grade / medicinal grade.

[0027] Detection of alliin and alliinase:

[0028] Performed on an LC-20A chromatograph (Shimadzu) using a C18 column (Venusil MP C18); methanol and 0.1% phosphoric acid with a volume ratio of 1:9 as the mobile phase, detected at 220 nm; prepared a standard solution using alliin and alliinase standards purchased from Shidande, and plotted a standard curve.

[0029] When calculating the content of alliin and alliinase in the black garlic sample, take different garlic cloves from the multi-headed black garlic of the batch to be tested, chop them; accurately weigh 15 g of the sample, add it to 100 mL of 10% methanol; crush it with a food processor; ultrasonically extract for 30 minutes at room temperature; filter and take the filtrate; after centrifugation, make up the volume to 200 mL as the black garlic extract sample for detecting alliin and alliinase.

[0030] Detection of allicin

[0031] Performed on an LC-20A chromatograph (Shimadzu) using a C18 column (Venusil MP C18); acetonitrile and water with a volume ratio of 7:3 as the mobile phase, detected at 215 nm; prepared a standard solution using the allicin standard purchased from Shidande, and plotted a standard curve.

[0032] When calculating the allicin content in the black garlic sample, take different garlic cloves from the multi-headed black garlic of the batch to be tested, chop them; accurately weigh 15 g of the sample, add it to 50 mL of distilled water, crush it with a food processor; extract by heating in a water bath at 50°C for 30 minutes; add 40 mL of methanol and stir to extract for 30 minutes; centrifuge and take the supernatant for filtration as the black garlic extract sample for detecting allicin.

[0033] Detection of total phenols:

[0034] Using the Folin-Ciocalteu method: Mix 1 mL of the sample with 1 mL of Folin-Ciocalteu reagent and 3 mL of 20% Na2CO3, react in a water bath at 50°C for 30 minutes, measure the light absorption at 765 nm; prepare a standard solution with gallic acid and plot a standard curve.

[0035] Detection of reducing sugar:

[0036] Using the DNS method: Mix 1 mL of the sample with 1 mL of DNS solution; react in a boiling water bath for 3 minutes, and after cooling, make up the volume and measure the light absorption at 540 nm; prepare a standard solution with glucose and plot a standard curve.

[0037] Basic extraction method of black garlic stock solution in Example 2

[0038] Through orthogonal experiments, the basic method for preparing black garlic stock solution by supercritical carbon dioxide extraction was determined as follows:

[0039] Peel, chop, freeze-dry, and pulverize black garlic, and then pass through a 100-mesh sieve to obtain freeze-dried black garlic powder;

[0040] Perform supercritical carbon dioxide extraction on the freeze-dried black garlic powder at an extraction temperature of 30 °C, an extraction pressure of 30 MPa, a carbon dioxide flow rate of 25 L / h, and an extraction time of 1.5 h.

[0041] Calculate that the extraction rate of allicin is about 54%, the extraction rate of polyphenolic components is about 61%, while the extraction rates of alliin and deoxyalliin are less than 25%.

[0042] Alliin and deoxyalliin in garlic / black garlic are known to have various medical and health functions such as anti-tumor and immune regulation. Since they are easily soluble in water, according to the literature reports, using water or an ethanol aqueous solution can achieve an extraction rate of 70-80%. If too much alliin and deoxyalliin are lost during the supercritical carbon dioxide extraction process, even if rich polyphenols, oils, allicin and other components can be extracted, the nutritional and health value of black garlic has not been fully utilized.

[0043] Use of entrainer in Example 3

[0044] Alliin and deoxyalliin belong to compounds with relatively strong polarity and are easily soluble in water. Therefore, the extraction rate is not good in supercritical carbon dioxide extraction. Considering the toxicity / subsequent treatment problems, the applicant tried to use ethanol as an entrainer and investigated the effects of different amounts of ethanol on the extraction rates of alliin and deoxyalliin

[0045] The ratio of freeze-dried black garlic powder to ethanol solution was fixed at 1:3 (w:w). The extraction rates of alliin and deoxyalliin when different concentrations of ethanol aqueous solutions were used as entrainers are shown in Table 1:

[0046] The results show that. Compared with when no entrainer is added, when the volume concentration of the ethanol aqueous solution is 50-90%, it has a positive effect on the extraction rates of alliin and deoxyalliin, and increases the extraction rate to above 30% level, but the effects among different concentrations of ethanol aqueous solutions are not very different. Select a 70% v / v concentration with a slightly higher extraction rate for subsequent experiments.

[0047] Example 4: Use of Surfactants

[0048] The applicant further considered adding surfactants to form a reverse micelle system or a similar encapsulation system to improve the extraction rate. A variety of food-grade surfactants were tried (70% v / v ethanol aqueous solution at 3 times the mass of the freeze-dried powder as the entrainer), and the results are as follows:

[0049] Table 2 Extraction Rates Using Different Surfactants

[0050]

[0051] Sodium dodecyl sulfate can effectively improve the extraction rates of alliin and deoxyallin. Although it is an excipient available in drugs, when used in foods or health products, its potential irritation requires that it must be removed in subsequent processing. In addition, the applicant noticed that in two experiments with monoglyceride succinate (5 parallel experiments for each surfactant), the extraction rate reached over 43%. Although it was very unstable, it also demonstrated its potential in improving the extraction rate. By further optimizing the amounts of surfactant and entrainer, it is expected to form a more stable reverse micelle system and improve the extraction rates of alliin and deoxyallin.

[0052] The following factors were set for an orthogonal experiment (n = 5):

[0053] A Amount of monoglyceride succinate: 1: 1%, 2: 1.5%, 3: 2%, 4: 2.5%, 5: 3%;

[0054] B Volume Concentration of Ethanol Aqueous Solution as Entrainer: 1: 50%, 2: 60%, 3: 70%, 4: 80%, 5: 90%

[0055] The results are shown in Table 3:

[0056] Table 3 Results of Orthogonal Experiment on Amount of Monoglyceride Succinate and Volume Concentration of Ethanol Aqueous Solution

[0057]

[0058] The results show that the A4B2 combination (2.5% monoglyceride succinate, 60% ethanol aqueous solution) not only has significantly higher average extraction rates of alliin and deoxyallin, but also has good stability after multiple repetitions, indicating that its reverse micelle system may be more stable. Further detection of the components in the extract shows that the extraction rate of allicin has also increased significantly compared to the initial method, reaching about 65%, while the extraction rate of polyphenolic components is about 60%.

[0059] By optimizing the parameters, entraining agents, and surfactants in the supercritical carbon dioxide extraction method, a supercritical carbon dioxide extraction method suitable for black garlic was constructed, which effectively improved the extraction effects of allicin, alliin / deoxyalliin.

Claims

1. A method for preparing black garlic stock solution by supercritical carbon dioxide extraction, characterized in that, The method includes: (1) peeling, chopping, freeze-drying, and pulverizing black garlic, and then sieving through a 50-200 mesh sieve to obtain black garlic freeze-dried powder; (2) adding the black garlic freeze-dried powder obtained in step (1) and monoglyceride succinate with a mass of 2.5% of the black garlic freeze-dried powder into an ethanol aqueous solution with a volume fraction of 60% and a mass 3 times that of the black garlic freeze-dried powder; after mixing, preparing black garlic stock solution by supercritical carbon dioxide extraction; the conditions for supercritical carbon dioxide extraction are an extraction temperature of 30 °C, an extraction pressure of 30 MPa, a carbon dioxide flow rate of 25 L / h, and an extraction time of 1.5 h.

2. The method according to claim 1, wherein step (1) is to peel, chop, freeze-dry, and pulverize black garlic, and then sieve through a 100 mesh sieve to obtain black garlic freeze-dried powder.

3. The method according to claim 1, wherein the black garlic is black garlic prepared from Cangshan garlic as the raw material.

4. A black garlic stock solution prepared by using the method according to any one of claims 1-3.

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