JP6486112B2 - Method for producing quercetin-containing extract - Google Patents

Description

  The present invention relates to a method for producing a quercetin-containing extract using onion as a raw material, and a quercetin-containing extract produced by the production method.

  Quercetin, a functional ingredient belonging to flavonols, has a strong antioxidant action, anti-inflammatory action, and blood smoothing effect, and is widely used in health foods and the like.

  Conventionally, it is known that quercetin is abundant in onions (especially the outer skin). Extracted from onions by hot water extraction or solvent extraction, and concentrated and dried to prepare a quercetin-containing extract. It is used for health foods.

  However, the quercetin-containing extract prepared by a conventional method has a problem that it contains a large amount of impurities other than quercetin and has low quercetin purity. Moreover, since many solvents are volatilized when preparing a powdery quercetin-containing extract, there is a problem that a large amount of energy is required by a large-sized concentrator or spray drying.

  Therefore, various methods for increasing the purity (concentration) of quercetin in the extract have been studied. For example, Patent Document 1 describes a method for producing a quercetin-containing product characterized by mixing a quercetin-containing liquid extracted from a quercetin-containing plant material into an aqueous solvent and a protein.

JP 2005-289850 A

  However, the method described in Patent Document 1 requires a step of adjusting pH, a step of adding and mixing a protein, and a step of releasing quercetin adsorbed on the protein, and there is a problem that the operation is complicated and not simple. is there. Moreover, the quercetin purity in the manufactured quercetin containing material is not sufficient, and there is room for improvement.

  This invention is made | formed in view of the said problem, and it aims at providing the manufacturing method with which the extract (quercetin containing extract) with high quercetin purity which uses onion as a raw material can be obtained simply.

  The present invention is an extraction process for extracting quercetin-containing extract by using hot onion as a raw material, a solid-liquid separation process 1 for separating the quercetin-containing extract and the raw material residue, and crystallizing quercetin contained in the quercetin-containing extract. The present invention relates to a method for producing a quercetin-containing extract comprising a crystallization step for crystallization and a solid-liquid separation step 2 for recovering the crystallization product.

  It is preferable that the temperature of the hot water in the extraction step is 60 to 150 ° C.

  The crystallization step is preferably a step of cooling the quercetin-containing extract to crystallize quercetin.

  After the crystallization process, it is preferable to include a grain growth process in which the extract containing the crystallized product is reheated to grow grains.

  Moreover, this invention relates to the quercetin containing extract manufactured by the said manufacturing method.

  According to the present invention, an onion extract having a high quercetin purity can be easily obtained by crystallizing quercetin contained in an onion hot water extract and recovering the crystallized product.

It is a graph which shows the extraction amount of quercetin and an impurity in the extract of an Example and a comparative example. It is a graph which shows the quercetin purity in the extract of an Example and a comparative example.

  The method for producing a quercetin-containing extract of the present invention includes an extraction step of extracting onion with hot water to obtain a quercetin-containing extract, a solid-liquid separation step 1 for separating the extract from the raw material residue, and a crystal for crystallizing quercetin. It is a manufacturing method of the quercetin containing extract including the solidification process and the solid-liquid separation process 2 which collect | recovers crystallized products.

Raw material The onion used as a raw material is not particularly limited as long as it is a bulb part of a plant classified as an onion belonging to the genus Laminaceae (hereinafter also simply referred to as onion). Although there are variations depending on the cultivar, quercetin is contained in the bulb part of the onion, so that it can be used as a raw material in the present invention without being limited to the cultivar. The onion to be used is most preferably the outer skin part that contains the most quercetin, but the endothelium located in the middle of the edible part inside the outer skin part and the edible part also contains quercetin. Therefore, each of these parts or a mixture of each part can be used as a raw material. Details of the quercetin content depending on the variety and part of the onion are widely known, for example, from literature such as N. Beesk et al., Food Chemistry, 122 (2010) 566.

  As the onion state, a raw state containing a lot of water, a dry state (absolutely dry state), a semi-dried state where some water has been blown off, and the like can be used. Moreover, although the onion used for hot water extraction may remain in its original form, it can also be obtained by separating scales or pulverized ones. It is more preferable to use dirt that has been removed by washing with water, air, a brush or the like. By removing only the outermost layer of the onion skin that is in contact with the soil during cultivation, the dirt can be greatly reduced.

  The onion includes a component called a glycoside in which 1 or 2 or 3 sugars are bound to quercetin, and this glycoside may also be included in the quercetin of the present invention. Further, hydrates in which water is bound to quercetin (most commonly 1-2 hydrates) are also known, but these hydrates may also be included in the quercetin of the present invention. Further, the quercetin of the present invention may contain both the aforementioned glycoside and hydrate obtained by binding water to quercetin.

Extraction Step The extraction step is a step of extracting the onion with hot water at a predetermined temperature to obtain a quercetin-containing extract.

  The solvent used in the extraction step is hot water, that is, water, but a solvent such as ethanol may be appropriately added within a range not impairing the effects of the present invention. Moreover, there is no limitation in particular as said water, Water which can be used for foodstuffs, such as a tap water, distilled water, well water, can be used.

  The amount of the solvent is preferably 5 times or more, and more preferably 30 times or more the mass of the onion in an absolutely dry state. The smaller the amount of the solvent, the easier the operation of the subsequent steps. However, when the amount of the solvent is less than 5 times, the extraction efficiency tends to deteriorate. Further, the amount of liquid is preferably 200 times or less. Even if it uses more than 200 times, the improvement of extraction efficiency is not seen, and when the quantity of a solvent is increased too much, there exists a tendency for the simplicity of a subsequent process to fall.

  The extraction temperature is preferably 60 ° C. or higher, more preferably 60 to 150 ° C., and still more preferably 90 to 99 ° C. When the extraction temperature is less than 60 ° C., components are hardly eluted from the onion, and the extraction efficiency tends to deteriorate. Moreover, when it exceeds 150 degreeC, quercetin will decompose | disassemble and there exists a tendency for extraction efficiency to deteriorate. When the extraction temperature is 90 to 99 ° C., the components are easily eluted from the onion, and quercetin is hardly decomposed, so that the extraction efficiency is most improved.

  The extraction time is preferably 5 minutes or more, and more preferably 30 minutes or more. When the extraction time is less than 5 minutes, components are hardly eluted from the onion, and the extraction efficiency tends to deteriorate. In addition, the extraction time is preferably 3 hours or less because no improvement in extraction efficiency is observed even if extraction is performed over 3 hours.

  The container used in the extraction step is not particularly limited as long as it can withstand the extraction temperature, and various kinds of containers such as metal such as stainless steel, ceramic, resin, and glass can be used. Especially at extraction temperatures close to 100 ° C or over 100 ° C, use a metal sealed container such as a commercially available pressure cooker or autoclave, or a ceramic sealed container for the reason that evaporation of water as a solvent can be prevented. Is preferred.

Solid-liquid separation process 1
The solid-liquid separation step 1 is a step of separating the quercetin-containing extract obtained in the extraction step and the raw material residue.

  Solid-liquid separation process 1 includes filtration, decantation, screw press, roller press, rotary drum screen, belt screen, vibration screen, multi-plate vibration filter, vacuum dehydration, pressure dehydration, belt press, centrifugal separation, centrifugal dehydration, Methods such as multiple disk dewatering can be employed. Of these, decantation is preferred for the reason that the operation is simple, and filtration and centrifugal dehydration are preferred for the reason of excellent separation efficiency.

  The filter medium used for the filtration is not particularly limited, and known filter papers and filters such as nonwoven fabric, woven fabric, cellulose filter paper, and glass filter paper can be used. Since the filtrate in the solid-liquid separation step 1 is a raw material residue, it is a relatively coarse nonwoven fabric, woven fabric, cellulose filter paper or glass filter paper with a large pore size, nylon mesh, polyester mesh, polypropylene mesh, polyethylene mesh, Aflon mesh, intersection A welded mesh or a metal mesh may be used.

  In addition, the solid-liquid separation step 1 can be performed immediately after the extraction step or after the temperature of the extraction solution is lowered. Even when the temperature of the extract is lowered, if the temperature is lowered to less than 60 ° C., quercetin tends to crystallize, and it is necessary to select an appropriate filter paper or filter. Preferably it is done. If a filter with a pore size larger than crystallized quercetin and a pore size smaller than the raw material residue can be used by selecting an appropriate filter paper or filter, the temperature of the extract in the solid-liquid separation step 1 is less than 60 ° C. It does not matter.

Crystallization Step The crystallization step is a step of crystallizing quercetin dissolved in the extract using the difference in solubility of quercetin with respect to the temperature of water. The quercetin-containing extract obtained in the solid-liquid separation step 1 Can be cooled to a predetermined temperature to crystallize quercetin. Note that the “crystallization step” described here is a step in which a precipitate containing quercetin is precipitated from the extract, and of course, other than an amorphous material having a solubility similar to quercetin. This material also precipitates. Also, quercetin itself has a very small precipitated particle morphology, or when water or other substances are taken in during precipitation, it does not become a so-called “crystal” in which atoms and molecules are regularly arranged. May be precipitated as an amorphous material, but the term “crystallization step” is used here, including such a broad meaning.

  Crystallization of quercetin begins gradually by cooling to a temperature that is 10 ° C. or lower than the hot water extraction temperature, but if the temperature after cooling (cooling temperature) is 60 ° C. or higher, the crystallization is not sufficient and the extraction efficiency is high. Since there is a tendency to deteriorate, the cooling temperature in the crystallization step is preferably less than 60 ° C, and more preferably 40 ° C or less. In addition, the lower limit of the cooling temperature is not particularly limited as long as the extract does not freeze.

  The cooling method may be rapid cooling using a refrigerant such as water, or may be slow cooling such as natural standing or air cooling. Slow cooling is preferred in that the quercetin crystals become relatively large crystals, the solid-liquid separation step 2 described later becomes easy, and the grain growth step described later may be unnecessary.

  The cooling time is preferably 5 minutes or more, and more preferably 30 minutes or more. When the cooling time is less than 5 minutes, crystallization is not sufficient and the extraction efficiency tends to deteriorate. Further, since no progress of crystallization is observed even after cooling for more than 48 hours, the cooling time is preferably 48 hours or less, and may be 24 hours or less. The cooling time in the present invention is the time after the extract reaches the target cooling temperature.

Grain Growth Step After the crystallization step, it is preferable to perform a grain growth step of growing the crystallized quercetin obtained in the crystallization step, that is, coarsening the crystal. By coarsening the crystallized product in this step, the solid-liquid separation step 2 described later can be performed more easily.

  Grain growth can be initiated by reheating the extract containing the crystallized product. The reheating temperature is preferably 10 ° C or higher than the cooling temperature in the crystallization step, and the temperature after reheating (reheating temperature) is preferably in the range of 4 to 80 ° C, and in the range of 20 to 70 ° C. More preferably. When the reheating temperature is less than 4 ° C., the grain growth efficiency tends to deteriorate. Moreover, when it exceeds 80 degreeC, there exists a tendency for a precipitate and a crystallized material to melt | dissolve again. It is preferable to set the reheating temperature in the range of 20 to 70 ° C. because the grain growth efficiency is good and the precipitate and the crystallized product are hardly re-dissolved.

  The reheating time is preferably 5 minutes or more, and more preferably 60 minutes or more. When the reheating time is less than 5 minutes, coarsening tends to be insufficient. Moreover, since the progress of coarsening is not seen even if it reheats over 12 hours, the reheating time is preferably 12 hours or less. The reheating time in the present invention is the time after the extract reaches the target reheating temperature.

  In the case where the coarsening of the crystallized product is insufficient in one grain growth step, the coarsening of the crystallized product is improved by repeating the crystallization step (cooling) and the grain growth step (reheating). There is.

Solid-liquid separation process 2
The solid-liquid separation step 2 is a step of recovering the precipitate containing the crystallized product obtained in the crystallization step or the precipitate containing the coarsened crystallized product obtained when the grain growth step is performed. The purity of quercetin can be increased by collecting a precipitate containing a crystallized product of quercetin and removing a liquid phase containing a large amount of impurities. Moreover, since many liquid phases can be removed, even if it is a case where a powdery quercetin containing extract is prepared, the remaining liquid phases can be volatilized simply.

  As the solid-liquid separation step 2, the same method as the above-mentioned solid-liquid separation step 1 can be employed. Of these, decantation is preferred for the reason that the operation is simple, and filtration and centrifugation are preferred for the reason of excellent separation efficiency.

  As the filter medium used for the filtration, the same filter medium as in the above-described solid-liquid separation step 1 can be used. However, since the filtrate in the solid-liquid separation step 2 is a precipitate containing a crystallized product, it is a relatively fine nonwoven fabric, woven fabric, cellulose filter paper or glass filter paper, nylon mesh, polyester mesh, polypropylene mesh, polyethylene mesh, Aflon mesh. It is preferable to use an intersection welded mesh, a metal mesh, or the like.

Post-processing step The post-processing step is a step of processing the precipitate collected in the solid-liquid separation step 2 into a form suitable for storage or a form that can be easily processed into a health food.

  The precipitate collected in the solid-liquid separation step 2 is a slurry containing water. Examples of the post-treatment step include adjusting the water content of the slurry, freezing the slurry, dissolving in a soluble organic solvent (such as ethanol), and drying, and may be appropriately selected or combined depending on the application. be able to. Among these, since a powdery and solid extract that is easier to handle can be obtained, a post-treatment step including drying is preferable.

  The drying method is not particularly limited, and natural drying, heating system drying, non-heating system drying, and the like can be employed. Examples of heating system drying include heat transfer drying such as box-type drying and spray drying, and internal heat generation drying such as microwave drying. Non-heating system drying includes freeze drying, vacuum drying, suction drying, and pressure drying. Ultrasonic drying and the like can be mentioned, but general and simple drying using an oven or a thermostat may also be used.

  According to the method for producing a quercetin-containing extract of the present invention, the method comprises a hot water extraction using onion as a raw material, a solid-liquid separation step 1, a crystallization step, and a solid-liquid separation step 2. An onion extract with high quercetin purity can be easily produced without performing complicated steps such as pH adjustment. Moreover, an onion extract with a high quercetin purity can be more easily manufactured by performing a grain growth process after a crystallization process.

  The purity of the quercetin-containing extract obtained by the production method of the present invention is high, the purity is 15% by mass or more, and the purity of the quercetin-containing extract obtained by the conventional method is less than 10% by mass. It can be said that it is a pure quercetin-containing extract. Moreover, in the manufacturing method of this invention, the purity of a quercetin containing extract can also obtain a quercetin containing extract 20 mass% or more.

  The present invention will be described based on examples, but the present invention is not limited to the examples.

Example 1
<Extraction process>
7 g of the crushed absolutely dry onion skin was put in a 500 ml beaker, 413 ml of hot water at 90 ° C. was added, and the mixture was stirred at 90 ° C. for 1 hour to perform hot water extraction.
<Solid-liquid separation step 1>
Immediately after the extraction, the extract and the residue were separated with cellulose filter paper (5A manufactured by ADVANTEC).
<Crystalling process>
The extract was placed in a 500 ml beaker and allowed to stand at 4 ° C. for 12 hours to precipitate and crystallize insoluble material containing quercetin. After standing, a precipitate was observed as a precipitate at the bottom of the beaker.
<Grain growth process>
Reheated to 60 ° C. and allowed to stand at 60 ° C. for 60 minutes to grow crystallized grains.
<Solid-liquid separation step 2>
A precipitate containing a crystallized product was recovered by filtration using cellulose filter paper (5C manufactured by ADVANTEC).
<Post-processing process>
The precipitate containing the recovered crystallized product was frozen at −80 ° C. and dried at room temperature for 12 hours by a freeze dryer (FDU-2200 manufactured by EYELA) to obtain a powdery extract.

Example 2
<Extraction process>
7 g of the crushed absolutely dry onion skin was put in a 500 ml beaker, 413 ml of hot water at 90 ° C. was added, and the mixture was stirred at 90 ° C. for 1 hour to perform hot water extraction.
<Solid-liquid separation step 1>
Immediately after the extraction, the extract and the residue were separated with cellulose filter paper (5A manufactured by ADVANTEC).
<Crystalling process>
The extract was placed in a 500 ml beaker and allowed to stand at 4 ° C. for 12 hours to precipitate and crystallize insoluble material containing quercetin. After standing, a precipitate was observed as a precipitate at the bottom of the beaker.
<Solid-liquid separation step 2>
A precipitate containing a crystallized product was recovered by filtration using cellulose filter paper (5C manufactured by ADVANTEC). The filtration time was about twice that of Example 1.
<Post-processing process>
The precipitate containing the recovered crystallized product was frozen at −80 ° C. and dried at room temperature for 12 hours by a freeze dryer (FDU-2200 manufactured by EYELA) to obtain a powdery extract.

Example 3
<Extraction process>
70 g of fresh onion skin (water content 90%) ground and washed with water was placed in a 500 ml beaker, 357 ml of 90 ° C. hot water was added, and the mixture was stirred at 90 ° C. for 1 hour to perform hot water extraction. .
<Solid-liquid separation step 1>
Immediately after the extraction, the extract and the residue were separated with cellulose filter paper (5A manufactured by ADVANTEC).
<Crystalling process>
The extract was placed in a 500 ml beaker and allowed to stand at 4 ° C. for 12 hours to precipitate and crystallize insoluble material containing quercetin. After standing, a precipitate was observed as a precipitate at the bottom of the beaker.
<Grain growth process>
Reheated to 60 ° C. and allowed to stand at 60 ° C. for 60 minutes to grow crystallized grains.
<Solid-liquid separation step 2>
The supernatant was removed by decantation, and a precipitate containing a crystallized product was recovered.
<Post-processing process>
The precipitate containing the recovered crystallized product was frozen at −80 ° C. and dried at room temperature for 12 hours by a freeze dryer (FDU-2200 manufactured by EYELA) to obtain a powdery extract.

Comparative Example 1
<Extraction process>
3 g of crushed absolutely dried onion skin was placed in a 500 ml beaker, 177 ml of hot water at 90 ° C. was added, and the mixture was stirred at 90 ° C. for 1 hour for hot water extraction.
<Solid-liquid separation process>
Immediately after the extraction, the extract and the residue were separated with cellulose filter paper (5A manufactured by ADVANTEC).
<Post-processing process>
The recovered extract was dried at 105 ° C. for 12 hours in an oven (Yamato Sterilizer SI401) to obtain an absolutely dry extract.

Comparative Example 2
<Extraction process>
Solvent extraction was performed by putting 1 g of ground dry onion skin into a 100 ml beaker, adding 30 ml of 99.5% ethanol, and stirring at room temperature for 12 hours.
<Solid-liquid separation process>
The extract and the residue were separated by filtration using cellulose filter paper (5A manufactured by ADVANTEC). Furthermore, about the residue, the said extraction process and filtration were performed again. Two filtrates were combined and collected as a sample for HPLC. A part of the filtrate was collected, ethanol was volatilized, and the solid content was also measured.

Component analysis of extract Each extract obtained in Examples 1 to 3 and Comparative Example 1 was dissolved in 99.5% ethanol in a 100 ml beaker to prepare a sample for HPLC. These HPLC samples and the HPLC sample of Comparative Example 2 were fixed in a 100 ml volumetric flask and then subjected to component analysis by high performance liquid chromatography (HPLC) to calculate the amount of quercetin. Then, the amount of quercetin extracted and the amount of impurities extracted per gram of the absolutely dry onion raw material and the purity of quercetin were calculated. The results are shown in Table 1 and FIGS.

The measurement conditions for HPLC are shown below.
Measuring device: LC-2010HT manufactured by Shimadzu Corporation
Column: COSMOSIL (registered trademark) MS-II Waters (φ4.6 × 250 mm) manufactured by Nacalai Tesque Co., Ltd.
Mobile phase: A; 0.1% formic acid, B: methanol
0min-8min; A: B = 90: 10 → 50: 50
8min-21min; A: B = 50: 50 → 30: 70
21min-25min; A: B = 30: 70
25min-25min50sec; A: B = 30: 70 → 0: 100
25min50sec-35min; A: B = 0: 100
35min-35min50sec; A: B = 0: 100 → 90: 10
35min50sec-45min50sec; A: B = 90: 10
Column temperature: 35 ° C
UV detection: 350 nm
Introduction amount: 10 μl
Flow rate: 0.6mL / min
Analysis time: 45 min
Standard reagent: Quercetin (≧ 99.0%, manufactured by CALBIOCHEM)

  From the results of Table 1 and FIGS. 1 and 2, the onion extract produced by the production method of the present invention has a quercetin purity of 15% by mass or more (from the results of Examples, the quercetin purity is 20% by mass or more. It can be seen that this is a highly pure onion extract. In Example 3, decantation was performed as the solid-liquid separation step 2 and a large amount of the supernatant was left. Therefore, the purity of quercetin was lower than that in Examples 1 and 2, but the purity was increased if the supernatant was further removed. Can do. On the other hand, in the production methods of Comparative Example 1 and Comparative Example 2, the extract is rich in impurities, and the quercetin purity is less than 10% by mass, indicating that the purity is low.

Claims (2)

Extraction process using hot water of 60 to 150 ° C. consisting of tap water, distilled water or well water, using onion as a raw material , to obtain a quercetin-containing extract,
Solid-liquid separation step 1 for separating the quercetin-containing extract and the raw material residue at a temperature of 60 ° C. or higher ,
A crystallization step in which quercetin contained in the quercetin-containing extract is crystallized by cooling at less than 60 ° C. , and a solid-liquid separation step 2 in which the crystallized product is recovered,
A process for producing a quercetin-containing extract. After the crystallization step, the manufacturing method according to claim 1 Symbol placement of quercetin-containing extract extract was reheated containing grain growth process, which grain growth including crystallizate.

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