Low-acidity fructus amomi extract and preparation method thereof

Abstract

The invention relates to the technical field of separation and purification, and particularly provides a low-acidity fructus amomi extract and a preparation method thereof. The preparation method comprises the following steps: adding a certain amount of alkaline agent into fructus amomi percolation juice, standing, crystallizing, filtering to remove crystals, collecting the filtered fructus amomi percolation juice, introducing a proper amount of carbon dioxide, filtering to remove precipitates, collecting the filtered fructus amomi percolation juice, and drying to obtain the low-acidity fructus amomi extract. The method is simple and easy to implement, high in repeatability and convenient for industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of separation and purification, and in particular to a low-acidity Amomum villosum extract and a preparation method thereof. Background Art

[0002] At present, food or medicine extracts with certain health connotations are often added to foods or beverages with health functions. However, most of the food or medicine extracts contain ingredients that make people feel unpleasant. These ingredients will make the product taste unpleasant, such as sour, and affect consumers' sensory experience.

[0003] At present, the research on Amomum villosum mainly focuses on its volatile components, and there are few reports on its non-volatile unpleasant taste components. The dried Amomum villosum extract is prepared by solvent extraction, concentration and drying of Amomum villosum. During the preparation process, the retention rate of volatile components is low, and its components are mainly non-volatile substances. There are many products on the market that use dried Amomum villosum extract as an additive. The dried Amomum villosum extract has been proven to have sour and bitter non-volatile unpleasant tastes, and sourness is its main unpleasant taste. At present, no research on the non-volatile unpleasant taste components in Amomum villosum has been found, nor is there a process method for specifically reducing the sour components in Amomum villosum. In order to improve the palatability of the dried Amomum villosum extract, the present invention proposes a process method for specifically reducing the sourness of the dried Amomum villosum extract, thereby promoting the healthy development of the Amomum villosum industry. Summary of the invention

[0004] In view of this, the present invention proposes a low-acidity Amomum villosum extract and a preparation method thereof, aiming to reduce the acidity of the Amomum villosum extract and enhance its taste.

[0005] The technical solution of the present invention is achieved as follows: The present invention provides a method for preparing a low-acidity Amomum villosum extract, which comprises the following steps:

[0006] Step 1, taking the percolation juice of Amomum villosum, adding an alkali agent, standing and crystallizing and filtering, and obtaining the percolation juice after the first filtration;

[0007] Step 2: introducing carbon dioxide into the filtered percolation juice until no new precipitation is generated, then stopping the introduction of carbon dioxide, filtering the precipitated precipitate, and drying the filtrate to obtain a low-acid Amomum villosum extract.

[0008] In some embodiments, the alkaline agent is calcium hydroxide.

[0009] In some embodiments, the amount of the alkaline agent is 0.4 wt % to 0.8 wt % of the Amomum villosum percolation juice.

[0010] In some embodiments, the standing crystallization time is 5-10 hours.

[0011] In a second aspect, the present invention also provides a low-acidity Amomum villosum extract prepared by the above method.

[0012] The low-acidity Amomum villosum extract prepared based on the above method has an acidity value reduced by more than 50% compared with the non-volatile sample obtained by volatilizing the Amomum villosum percolation juice.

[0013] In a third aspect, the present invention further provides a method for identifying non-volatile sour substances in Amomum villosum percolation juice, comprising the following steps:

[0014] (1) Preparation of non-volatile sample of Amomum villosum percolation juice: firstly, the volatile components in the Amomum villosum percolation juice are removed by steam distillation. Specifically, 2-3 volumes of ultrapure water are added to the Amomum villosum percolation juice, and the volatile components in the Amomum villosum percolation juice are boiled and distilled out. Then, the Amomum villosum percolation juice after the volatile components are removed is used as a raw material, and the non-volatile sample of the Amomum villosum percolation juice is prepared by combining reduced pressure drying and vacuum freeze drying.

[0015] (2) Separation, purification, drying and sensory evaluation of the main active ingredient monomers in the non-volatile sample of Amomum villosum percolation juice: 1 g of the non-volatile sample of Amomum villosum percolation juice prepared in step (1) was taken, and the non-volatile sample of Amomum villosum percolation juice was dissolved in pure water, filtered through a microporous filter membrane to obtain a filtrate, and different fractions in the non-volatile sample of Amomum villosum percolation juice were separated, purified and vacuum freeze-dried using a high-performance preparative liquid chromatograph to obtain 6 high-purity monomer fraction samples, which were numbered 1 to 6. Then, the samples numbered 1 to 6 were subjected to sensory evaluation to obtain sour fraction samples, and their numbers were recorded;

[0016] (3) Identification of sour-tasting fraction samples: UPLC-Q-TOF / MS technology and liquid chromatography technology were used to jointly identify the specific types of sour-tasting fraction substances.

[0017] In the above step (1), the volume of ultrapure water added during steam distillation is 2-3 times the volume of the Amomum villosum percolation juice, and the order of vacuum drying and vacuum freeze drying is first vacuum drying and then vacuum freeze drying. The temperature of vacuum drying is 65-85°C, and the vacuum degree is -0.8Mpa to -1.0Mpa.

[0018] In the above step (2), the concentration of the non-volatile sample solution of Amomum villosum percolation juice is 10-15 mg / mL, the pore size of the microporous filter membrane is 0.22-0.45 μm, and the chromatographic conditions of the high performance preparative liquid chromatography are: chromatographic column: Daisogel C18-10 um-120A (20 mm×250 mm) preparative chromatographic column, detection wavelength 220-400 nm, and the elution gradient of the mobile phase of the high performance preparative liquid chromatography is as follows:

[0019] Time (min) A / acetonitrile (%) B / 0.1% phosphoric acid aqueous solution (%) 0 10～25 75～90 20 25～40 60～75 40 40 60 60 40 60

[0020] A total of 6 fractions were obtained by separating and purifying the non-volatile samples in the percolation juice of Amomum villosum using high performance preparative liquid chromatography. The sour fractions were distributed in the time periods of 18.200min-19.100min, 25.120min-26.500min and 36.000min-37.300min, and the sour fractions were numbered as fraction 2, fraction 4 and fraction 6, respectively.

[0021] In the above step (3), the UPLC-Q-TOF / MS detection conditions are: chromatographic column: Waters ACQUITY UPLC HSST3 C18 column, flow rate of 0.3-0.7 mL / min, column temperature of 25°C-35°C, injection volume: reference 0.08-0.10 μL, sample solution 0.2-0.4 μL, mobile phase: A 0.1% acetic acid aqueous solution, B 0.1% acetic acid acetonitrile solution, mobile phase elution gradient:

[0022]

[0023]

[0024] The liquid chromatography conditions were as follows: Agilent ZORBAX SB-Aq C18 column (4.6mm×250mm, 5μm); detection wavelength 260nm; flow rate 1.0mL / min; column temperature 30℃; injection volume 10μL; mobile phase: methanol (A), 0.05% formic acid solution (B); gradient elution conditions: 0min, 10%A; 6min, 10%A; 10min, 12%A; 20min, 12%A; 60min, 15%A. The relative errors of the peak times of the liquid chromatograms of the sour-tasting fractions 2, 4 and 6 and the corresponding commercially available standards were no more than 3%. Fractions 2, 4 and 6 were identified as protocatechuic acid, DL-malic acid and p-hydroxybenzoic acid, respectively, among which DL-malic acid was the main sour substance.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention uses high-performance preparative liquid chromatography technology, UPLC-Q-TOF / MS technology and other advanced analytical technologies to identify the sour components in the Amomum villosum extract, so that production personnel can fully understand the specific types of the reduced sour components, and specifically proposes a process method for removing the sour components step by step by using an alkali agent and carbon dioxide. The preparation process is simple and easy, which is conducive to industrial production. The obtained low-acidity Amomum villosum extract has a low acidity value, thereby increasing the application range of the low-acidity Amomum villosum extract. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 The liquid chromatogram of the non-volatile sample of Amomum villosum percolation juice in Example 1 of the present invention when separated and purified by high performance preparative liquid chromatography;

[0029] Figure 2 The secondary mass spectrum of fraction 6 in Example 1 of the present invention and possible fragmentation pathways;

[0030] Figure 3 The secondary mass spectrum of fraction 2 in Example 1 of the present invention and possible fragmentation pathways;

[0031] Figure 4 The secondary mass spectrum of fraction 4 in Example 1 of the present invention and possible fragmentation pathways;

[0032] Figure 5 1 is a high performance liquid chromatogram of fraction 2, fraction 4 and fraction 6 (A) and their corresponding standard product (B) in Example 1 of the present invention. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the embodiments of the present invention belong. If the definitions set forth in this section are contrary to or otherwise inconsistent with the definitions set forth in the patents, patent applications, published patent applications, and other publications incorporated herein by reference, the definitions listed in this section take precedence over the definitions incorporated herein by reference.

[0035] Unless otherwise specified, the methods used in the following examples are all conventional methods. Unless otherwise specified, the materials, reagents and instruments used are all conventional materials, reagents and instruments in the art, and can be obtained by those skilled in the art through commercial channels.

[0036] When an amount, concentration or other value or parameter is expressed as a range, a preferred range or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including the range "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range. In the present specification and claims, range definitions can be combined and / or interchanged, and if not otherwise stated, these ranges include all subranges contained therein.

[0037] Example 1

[0038] This embodiment provides a method for identifying non-volatile sour substances in Amomum villosum percolation juice and preparing a low-acid Amomum villosum extract, which specifically comprises the following steps:

[0039] (1) Accurately measure 2L of Amomum villosum percolation juice and add 4L of ultrapure water to mix evenly, boil and distill the volatile components in the Amomum villosum percolation juice by steam distillation, collect 2L of Amomum villosum percolation juice after removing the volatile components, and then use reduced pressure drying at a temperature of 65°C and a vacuum degree of -0.8Mpa to obtain an Amomum villosum dried product, and then continue to dry the Amomum villosum dried product by vacuum freeze drying to obtain 35g of Amomum villosum percolation juice non-volatile sample. Take 1g of the prepared Amomum villosum percolation juice non-volatile sample, use ultrapure water to dissolve the Amomum villosum percolation juice non-volatile sample to a concentration of 10mg / mL, pass through a microporous filter membrane with a pore size of 0.22μm to obtain a filtrate, and use a high performance preparative liquid chromatograph to separate, purify and vacuum freeze-dry different fractions in the Amomum villosum percolation juice non-volatile sample to obtain 6 high-purity monomer fraction samples, which are numbered 1-6 respectively. Then, the samples No. 1-6 were subjected to sensory evaluation to obtain the sour fraction samples, which were fraction 2, fraction 4 and fraction 6, respectively. The HPLC conditions were as follows: chromatographic column: Daisogel C18-10 um-120A (20 mm × 250 mm) preparative chromatographic column, detection wavelength 220-400 nm, and the mobile phase elution gradient of the HPLC was as follows:

[0040] Time (min) A / acetonitrile (%) B / 0.1% phosphoric acid aqueous solution (%) 0 10 90 20 25 75 40 40 60 60 40 60

[0041] (2) Fraction 2, fraction 4 and fraction 6 were identified using UPLC-Q-TOF / MS technology. The chromatographic conditions were as follows: chromatographic column: Waters ACQUITY UPLC HSS T3 C18 column, flow rate: 0.3 mL / min, column temperature: 25°C, injection volume: reference substance 0.08 μL, sample solution: 0.2 μL, mobile phase: A: 0.1% acetic acid aqueous solution, B: 0.1% acetic acid acetonitrile solution, mobile phase elution gradient:

[0042] Time (min) A(％) B(％) 0 100 0 10 90 10 20 60 40 28 15 85 30 100 0 35 100 0

[0043] According to the data in the UPLC-Q-TOF / MS secondary mass spectrum, fraction 2, fraction 4 and fraction 6 were inferred to be protocatechuic acid, DL-malic acid and p-hydroxybenzoic acid, respectively. Then, fraction 2, fraction 4 and fraction 6 were subjected to liquid chromatography detection with the corresponding commercially available standards, and the peak times were compared. The liquid chromatography conditions were as follows: liquid chromatography conditions: Agilent ZORBAX SB-Aq C18 column (4.6mm×250mm, 5μm); detection wavelength 260nm; flow rate 1.0mL / min; column temperature 30℃; injection volume 10μL; mobile phase: methanol (A), 0.05% formic acid solution (B); gradient elution conditions: 0min, 10%A; 6min, 10%A; 10min, 12%A; 20min, 12%A; 60min, 15%A. The results showed that fraction 2, fraction 4 and fraction 6 were protocatechuic acid, DL-malic acid and p-hydroxybenzoic acid, respectively.

[0044] (3) Accurately measure 2 L of Amomum villosum percolation juice, add 8 g of calcium hydroxide to the Amomum villosum percolation juice, stir to dissolve, and then stand for crystallization for 5 h, then filter with a 300-mesh sieve to remove DL-calcium malate crystals, and collect 1.89 L of filtered Amomum villosum percolation juice. Pass carbon dioxide into the filtered Amomum villosum percolation juice, and filter to remove calcium carbonate precipitates when a large amount of precipitates are generated, collect the filtered Amomum villosum percolation juice, and obtain 30 g of low-acid Amomum villosum extract after low-temperature vacuum drying.

[0045] Example 2

[0046] This embodiment provides a method for identifying non-volatile sour substances in Amomum villosum percolation juice and preparing a low-acid Amomum villosum extract, which specifically comprises the following steps:

[0047] (1) Accurately measure 2L of Amomum villosum percolation juice and add 5L of ultrapure water to mix evenly, boil and distill the volatile components in the Amomum villosum percolation juice by steam distillation, collect 3L of Amomum villosum percolation juice after removing the volatile components, and then use reduced pressure drying at a temperature of 75°C and a vacuum degree of -0.9 MPa to obtain an Amomum villosum dried product, and then continue to dry the Amomum villosum dried product by vacuum freeze drying to obtain 34.7g of Amomum villosum percolation juice non-volatile sample. Take 1g of the prepared Amomum villosum percolation juice non-volatile sample, use ultrapure water to dissolve the Amomum villosum percolation juice non-volatile sample to a concentration of 12mg / mL, pass through a microporous filter membrane with a pore size of 0.22μm to obtain a filtrate, and use a high performance preparative liquid chromatograph to separate, purify and vacuum freeze-dry different fractions in the Amomum villosum percolation juice non-volatile sample to obtain 6 high-purity monomer fraction samples, which are numbered 1-6 respectively. Then, the samples No. 1-6 were subjected to sensory evaluation to obtain the sour fraction samples, which were fraction 2, fraction 4 and fraction 6, respectively. The HPLC conditions were as follows: chromatographic column: Daisogel C18-10 um-120A (20 mm × 250 mm) preparative chromatographic column, detection wavelength 220-400 nm, and the mobile phase elution gradient of the HPLC was as follows:

[0048] Time (min) A / acetonitrile (%) B / 0.1% phosphoric acid aqueous solution (%) 0 22 78 20 30 70 40 40 60 60 40 60

[0049] (2) Fraction 2, fraction 4 and fraction 6 were identified using UPLC-Q-TOF / MS technology. The chromatographic conditions were as follows: chromatographic column: Waters ACQUITY UPLC HSS T3 C18 column, flow rate: 0.5 mL / min, column temperature: 30°C, injection volume: reference substance 0.09 μL, sample solution 0.3 μL, mobile phase: A 0.1% acetic acid aqueous solution, B 0.1% acetic acid acetonitrile solution, mobile phase elution gradient:

[0050] Time (min) A(％) B(％) 0 100 0 10 90 10 20 60 40 28 15 85 30 100 0 35 100 0

[0051] According to the data in the UPLC-Q-TOF / MS secondary mass spectrum, fraction 2, fraction 4 and fraction 6 were inferred to be protocatechuic acid, DL-malic acid and p-hydroxybenzoic acid, respectively. Then, fraction 2, fraction 4 and fraction 6 were subjected to liquid chromatography detection with the corresponding commercially available standards, and the peak times were compared. The liquid chromatography conditions were as follows: liquid chromatography conditions: Agilent ZORBAX SB-Aq C18 column (4.6mm×250mm, 5μm); detection wavelength 260nm; flow rate 1.0mL / min; column temperature 30℃; injection volume 10μL; mobile phase: methanol (A), 0.05% formic acid solution (B); gradient elution conditions: 0min, 10%A; 6min, 10%A; 10min, 12%A; 20min, 12%A; 60min, 15%A. The results showed that fraction 2, fraction 4 and fraction 6 were protocatechuic acid, DL-malic acid and p-hydroxybenzoic acid, respectively.

[0052] (3) Accurately measure 2 L of Amomum villosum percolation juice, add 12 g of calcium hydroxide to the Amomum villosum percolation juice, stir to dissolve, and then stand for crystallization for 8 h, then filter with a 300-mesh sieve to remove DL-calcium malate crystals, and collect 1.83 L of filtered Amomum villosum percolation juice. Pass carbon dioxide into the filtered Amomum villosum percolation juice, and filter to remove calcium carbonate precipitates when a large amount of precipitates are generated, collect the filtered Amomum villosum percolation juice, and obtain 29.6 g of low-acid Amomum villosum extract after low-temperature vacuum drying.

[0053] Example 3

[0054] This embodiment provides a method for identifying non-volatile sour substances in Amomum villosum percolation juice and preparing a low-acid Amomum villosum extract, which specifically comprises the following steps:

[0055] (1) Accurately measure 2L of Amomum villosum percolation juice and add 6L of ultrapure water to mix evenly, boil and distill the volatile components in the Amomum villosum percolation juice by steam distillation, collect 4L of Amomum villosum percolation juice after removing the volatile components, and then use reduced pressure drying at a temperature of 85°C and a vacuum degree of -1.0 MPa to obtain an Amomum villosum dried product, and then continue to dry the Amomum villosum dried product by vacuum freeze drying to obtain 34.5g of Amomum villosum percolation juice non-volatile sample. Take 1g of the prepared Amomum villosum percolation juice non-volatile sample, use ultrapure water to dissolve the Amomum villosum percolation juice non-volatile sample to a concentration of 15mg / mL, pass through a microporous filter membrane with a pore size of 0.45μm to obtain a filtrate, and use a high performance preparative liquid chromatograph to separate, purify and vacuum freeze-dry different fractions in the Amomum villosum percolation juice non-volatile sample to obtain 6 high-purity monomer fraction samples, which are numbered 1-6 respectively. Then, the samples No. 1-6 were subjected to sensory evaluation to obtain the sour fraction samples, which were fraction 2, fraction 4 and fraction 6, respectively. The HPLC conditions were as follows: chromatographic column: Daisogel C18-10 um-120A (20 mm × 250 mm) preparative chromatographic column, detection wavelength 220-400 nm, and the mobile phase elution gradient of the HPLC was as follows:

[0056] Time (min) A / acetonitrile (%) B / 0.1% phosphoric acid aqueous solution (%) 0 25 75 20 40 60 40 40 60 60 40 60

[0057] (2) Fraction 2, fraction 4 and fraction 6 were identified using UPLC-Q-TOF / MS technology. The chromatographic conditions were as follows: chromatographic column: Waters ACQUITY UPLC HSS T3 C18 column, flow rate: 0.7 mL / min, column temperature: 35°C, injection volume: reference substance 0.10 μL, sample solution 0.4 μL, mobile phase: A 0.1% acetic acid aqueous solution, B 0.1% acetic acid acetonitrile solution, mobile phase elution gradient:

[0058] Time (min) A(％) B(％) 0 100 0 10 90 10 20 60 40 28 15 85 30 100 0 35 100 0

[0059] According to the data in the UPLC-Q-TOF / MS secondary mass spectrum, fraction 2, fraction 4 and fraction 6 were inferred to be protocatechuic acid, DL-malic acid and p-hydroxybenzoic acid, respectively. Then, fraction 2, fraction 4 and fraction 6 were subjected to liquid chromatography detection with the corresponding commercially available standards, and the peak times were compared. The liquid chromatography conditions were as follows: liquid chromatography conditions: Agilent ZORBAX SB-Aq C18 column (4.6mm×250mm, 5μm); detection wavelength 260nm; flow rate 1.0mL / min; column temperature 30℃; injection volume 10μL; mobile phase: methanol (A), 0.05% formic acid solution (B); gradient elution conditions: 0min, 10%A; 6min, 10%A; 10min, 12%A; 20min, 12%A; 60min, 15%A. The results showed that fraction 2, fraction 4 and fraction 6 were protocatechuic acid, DL-malic acid and p-hydroxybenzoic acid, respectively.

[0060] (3) Accurately measure 2 L of Amomum villosum percolation juice, add 16 g of calcium hydroxide to the Amomum villosum percolation juice, stir to dissolve, and then stand for crystallization for 10 h, then filter with a 300-mesh sieve to remove DL-calcium malate crystals, and collect 1.88 L of filtered Amomum villosum percolation juice. Pass carbon dioxide into the filtered Amomum villosum percolation juice, and filter to remove calcium carbonate precipitates when a large amount of precipitates are generated, collect the filtered Amomum villosum percolation juice, and obtain 30.1 g of low-acid Amomum villosum extract after low-temperature vacuum drying.

[0061] The low-acid Amomum extract prepared in Example 1-3 and the non-volatile sample of Amomum percolation juice in step (1) of Example 1-3 were subjected to electronic tongue measurement. Each sample was prepared into a solution with a concentration of 8 mg / mL with pure water, and the sourness value of each sample was tasted 3 times with an electronic tongue, and the average value of the three times was taken. The measurement results are shown in the following table:

[0062]

[0063] It is shown that the acidity value of the low-acidity Amomum villosum extract prepared by the method of the present invention is significantly reduced by more than 50% compared with the Amomum villosum extract prepared by conventional extraction.

[0064] The effective components in the non-volatile sample of the Amomum villosum percolation juice in step (1) of Example 1 were separated and purified using high performance preparative liquid chromatography. The preparative liquid chromatogram is shown in the attached figure. Figure 1 As shown, a total of 6 fractions were obtained.

[0065] Fraction 2, fraction 4 and fraction 6 were identified using UPLC-Q-TOF / MS technology and liquid chromatography technology, respectively, and the secondary mass spectra of fraction 2, fraction 4 and fraction 6 were obtained, respectively. The mass spectrometry fragmentation mode of each fraction was analyzed, and the following identification results were obtained:

[0066] Fraction 6: As attached Figure 2 As shown in Figure 1, according to the mass spectrometry data obtained in the negative ion mode, the quasi-molecular ion peak of fraction 6 is m / z 137.0288 [MH]-, and the quasi-molecular ion peak removes one CO molecule (28Da) to obtain a high-abundance ion fragment m / z 109.0322 [MH-CO]-. Combined with the literature and KingDraw drawing software, the fragmentation pathway of fraction 6 was analyzed and it was inferred that fraction 6 was p-hydroxybenzoic acid. Fraction 2: As shown in the attached Figure 3 As shown in the figure, the mass spectrum data of fraction 2 shows that m / z 153.0188[MH]- is its quasi-molecular ion peak. The fragment ion m / z 109.0322[MH-COOH]- is obtained by losing one molecule of COOH (44Da) from the quasi-molecular ion peak m / z153.0188[MH]-. Combining the literature and using KingDraw drawing software to analyze the fragmentation pathway of fraction 2, it is inferred that fraction 2 is protocatechuic acid. Fraction 4: As shown in the figure Figure 4 As shown, the mass spectrometry data of fraction 4 were analyzed and it was found that its quasi-molecular ion peak was m / z 133.0198 [MH]-. After removing one molecule of water (18 Da), a fragment ion m / z 115.0065 [MH-H2O]- was obtained. Combined with the literature and using KingDraw drawing software to analyze the cleavage pathway of fraction 4, it was inferred that fraction 4 was DL-malic acid.

[0067] The fractions 2, 4 and 6 were tested by liquid chromatography with the corresponding commercially available standards using a high performance liquid chromatograph, and the peak times were compared. The results are shown in the attached figure. Figure 5 As shown, in Figure A, fraction 4 (peak 1); fraction 2 (peak 2); fraction 6 (peak 4), in Figure B, DL-malic acid standard (peak 1); protocatechuic acid standard (peak 2); p-hydroxybenzoic acid standard (peak 4). The peak elution time of each fraction is basically the same as that of the corresponding commercial standard, indicating that fraction 2, fraction 4 and fraction 6 are protocatechuic acid, DL-malic acid and p-hydroxybenzoic acid, respectively.

[0068] Comparative Example 1

[0069] Accurately measure 2L of Amomum villosum percolation juice, add 8g of sodium hydroxide to the Amomum villosum percolation juice, stir to dissolve, and then stand for crystallization for 5h without precipitation, and collect 2L of filtered Amomum villosum percolation juice. Pass carbon dioxide into the filtered Amomum villosum percolation juice, and without precipitation, collect the filtered Amomum villosum percolation juice, and obtain a low-acid Amomum villosum extract after low-temperature vacuum drying.

[0070] Comparative Example 2

[0071] Accurately measure 2L of Amomum villosum percolation juice, add 8g of potassium hydroxide to the Amomum villosum percolation juice, stir to dissolve, and then stand for crystallization for 5h without precipitation, and collect 2L of filtered Amomum villosum percolation juice. Pass carbon dioxide into the filtered Amomum villosum percolation juice, and without precipitation, collect the filtered Amomum villosum percolation juice, and obtain a low-acid Amomum villosum extract after low-temperature vacuum drying.

[0072] The Amomum villosum percolation juice obtained by standing and crystallizing in Example 1, Comparative Example 1 and Comparative Example 2 was filtered and sent to the acidity test. The acidity of the samples was tasted 3 times with an electronic tongue, and the average value of the three times was taken. The test results are shown in the following table:

[0073]

[0074] From the above data, it can be seen that the use of calcium hydroxide can significantly reduce the acidity value of the Amomum villosum percolated juice, while the use of sodium hydroxide and potassium hydroxide cannot significantly reduce the acidity value of the Amomum villosum percolated juice.

[0075] Comparative Example 3

[0076] Accurately measure 2L of Amomum villosum percolation juice, add 4g of calcium hydroxide to the Amomum villosum percolation juice, stir to dissolve, and then stand for crystallization for 5 hours, then filter with a 300-mesh sieve to remove DL-calcium malate crystals, and collect the filtered Amomum villosum percolation juice. Pass carbon dioxide into the filtered Amomum villosum percolation juice, filter to remove calcium carbonate precipitation when a large amount of precipitation is generated, collect the filtered Amomum villosum percolation juice, and obtain a low-acid Amomum villosum extract after low-temperature vacuum drying.

[0077] Comparative Example 4

[0078] Accurately measure 2L of Amomum villosum percolation juice, add 20g of calcium hydroxide to the Amomum villosum percolation juice, stir to dissolve, and then stand for crystallization for 5 hours, then use a 300-mesh sieve to filter out DL-calcium malate crystals, and collect the filtered Amomum villosum percolation juice. Pass carbon dioxide into the filtered Amomum villosum percolation juice, filter to remove calcium carbonate precipitation when a large amount of precipitation is generated, collect the filtered Amomum villosum percolation juice, and obtain a low-acid Amomum villosum extract after low-temperature vacuum drying.

[0079] Comparative Example 5

[0080] Accurately measure 2L of Amomum villosum percolation juice, add 24g of calcium hydroxide to the Amomum villosum percolation juice, stir to dissolve, and then stand for crystallization for 5 hours, then use a 300-mesh sieve to filter out DL-calcium malate crystals, and collect the filtered Amomum villosum percolation juice. Pass carbon dioxide into the filtered Amomum villosum percolation juice, filter to remove calcium carbonate precipitation when a large amount of precipitation is generated, collect the filtered Amomum villosum percolation juice, and obtain a low-acid Amomum villosum extract after low-temperature vacuum drying.

[0081] The Amomum villosum percolation juice obtained by standing and crystallizing in Example 1 and Comparative Examples 3-5 was filtered and sent to the acidity test. The acidity of the samples was tasted 3 times with an electronic tongue, and the average value of the three times was taken. The test results are shown in the following table:

[0082] Calcium hydroxide addition amount / % Acidity value reduction rate / % 0.2 12.13 0.4 55.29 0.6 58.75 0.8 62.76 1.0 62.89 1.2 62.56

[0083] It can be seen from the above table that when the addition amount of calcium hydroxide is higher than 0.4%, the acidity reduction rate of the Amomum villosum percolation juice is higher than 50%, and when the addition amount of calcium hydroxide is higher than 0.8%, the acidity reduction rate of the Amomum villosum percolation juice is not significantly improved.

[0084] Comparative Example 6

[0085] Accurately measure 2L of Amomum villosum percolation juice, add 8g of calcium hydroxide to the Amomum villosum percolation juice, stir to dissolve, and then stand for crystallization for 2.5 hours, then use a 300-mesh sieve to filter out DL-calcium malate crystals, and collect the filtered Amomum villosum percolation juice. Pass carbon dioxide into the filtered Amomum villosum percolation juice, filter to remove calcium carbonate precipitation when a large amount of precipitation is generated, collect the filtered Amomum villosum percolation juice, and obtain a low-acid Amomum villosum extract after low-temperature vacuum drying.

[0086] Comparative Example 7

[0087] Accurately measure 2L of Amomum villosum percolation juice, add 8g of calcium hydroxide to the Amomum villosum percolation juice, stir to dissolve, and then stand for crystallization for 7.5h, then use a 300-mesh sieve to filter out DL-calcium malate crystals, and collect the filtered Amomum villosum percolation juice. Pass carbon dioxide into the filtered Amomum villosum percolation juice, filter to remove calcium carbonate precipitation when a large amount of precipitation is generated, collect the filtered Amomum villosum percolation juice, and obtain a low-acid Amomum villosum extract after low-temperature vacuum drying.

[0088] Comparative Example 8

[0089] Accurately measure 2L of Amomum villosum percolation juice, add 8g of calcium hydroxide to the Amomum villosum percolation juice, stir to dissolve, and then stand for crystallization for 10 hours, then filter with a 300-mesh sieve to remove DL-calcium malate crystals, and collect the filtered Amomum villosum percolation juice. Pass carbon dioxide into the filtered Amomum villosum percolation juice, filter to remove calcium carbonate precipitation when a large amount of precipitation is generated, collect the filtered Amomum villosum percolation juice, and obtain a low-acid Amomum villosum extract after low-temperature vacuum drying.

[0090] Comparative Example 9

[0091] Accurately measure 2L of Amomum villosum percolation juice, add 8g of calcium hydroxide to the Amomum villosum percolation juice, stir to dissolve, and then stand for crystallization for 12.5h, then use a 300-mesh sieve to filter out DL-calcium malate crystals, and collect the filtered Amomum villosum percolation juice. Pass carbon dioxide into the filtered Amomum villosum percolation juice, filter to remove calcium carbonate precipitation when a large amount of precipitation is generated, collect the filtered Amomum villosum percolation juice, and obtain a low-acid Amomum villosum extract after low-temperature vacuum drying.

[0092] Comparative Example 10

[0093] Accurately measure 2L of Amomum villosum percolation juice, add 8g of calcium hydroxide to the Amomum villosum percolation juice, stir to dissolve, and then stand for crystallization for 15 hours, then use a 300-mesh sieve to filter out DL-calcium malate crystals, and collect the filtered Amomum villosum percolation juice. Pass carbon dioxide into the filtered Amomum villosum percolation juice, filter to remove calcium carbonate precipitation when a large amount of precipitation is generated, collect the filtered Amomum villosum percolation juice, and obtain a low-acid Amomum villosum extract after low-temperature vacuum drying.

[0094] The Amomum villosum percolation juice obtained by standing and crystallizing in Example 1 and Comparative Examples 6 to 10 was filtered and sent to the acidity test. The acidity of the samples was tasted 3 times with an electronic tongue, and the average value of the three times was taken. The test results are shown in the following table:

[0095] Standing crystallization time / h Acidity value reduction rate / % 2.5 23.14 5 55.29 7.5 56.75 10 61.59 12.5 61.89 15 61.78

[0096] It can be seen from the above table that when the standing crystallization time is higher than 5h, the acidity value reduction rate of the Amomum villosum percolation juice is higher than 50%, and when the standing crystallization time is higher than 10h, the acidity value reduction rate of the Amomum villosum percolation juice does not increase significantly.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a low-acidity Amomum villosum extract, characterized in that: The steps include: Step 1, taking the percolation juice of Amomum villosum, adding an alkali agent, standing and crystallizing and filtering, and obtaining the percolation juice after the first filtration; Step 2: introducing carbon dioxide into the filtered percolation juice until no new precipitate is generated, then stopping the introduction of carbon dioxide, filtering the precipitate, and drying the filtrate to obtain a low-acid Amomum villosum extract.

2. The method for preparing the low-acidity Amomum villosum extract according to claim 1, characterized in that: The alkali agent is calcium hydroxide.

3. The method for preparing the low-acidity Amomum villosum extract according to claim 1, characterized in that: The dosage of the alkali agent is 0.4wt%-0.8wt% of the Amomum villosum percolation juice.

4. The method for preparing the low-acidity Amomum villosum extract according to claim 1, characterized in that: The standing crystallization time is 5-10h.

5. A low-acidity Amomum villosum extract, characterized in that The preparation method is described in any one of claims 1 to 4.

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