Noni polyphenol and extraction method thereof

Abstract

The invention belongs to the technical field of polyphenol extraction, and particularly relates to morinda citrifolia polyphenol and an extraction method thereof. According to the invention, a far infrared auxiliary pulse vacuum drying technology is utilized, so that the morinda citrifolia pomace can be quickly dried, degradation of heat-sensitive components is reduced, and more active components are reserved; the dried morinda citrifolia pomace can be further refined by utilizing an airflow superfine grinding technology, the contact area of an extraction solvent and the pomace is increased, and sufficient release of polyphenol is promoted; the morinda citrifolia pomace powder is extracted by taking the ethanol water solution as a solvent, and the extraction conditions are strictly limited, so that the extraction efficiency of the polyphenol is improved. The result of the embodiment shows that the extraction rate of the extracted morinda citrifolia polyphenol reaches 344.50-369.25 mu g / g, the morinda citrifolia polyphenol has high antioxidant activity, compared with a traditional extraction technology, the polyphenol extraction rate can be increased by 5-10%, high-value utilization of by-products is achieved while environmental pollution is avoided, and the morinda citrifolia polyphenol extraction method has the advantages of being efficient, capable of saving energy and environmentally friendly and can be used for large-scale industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of polyphenol extraction, and particularly relates to noni polyphenol and an extraction method thereof. Background Art

[0002] Noni, whose scientific name is Morinda citrifolia Linn, is also known as Noni, Luoli, and Morinda citrifolia Linn. It is a tropical evergreen perennial broad-leaved shrub or small tree of the Rubiaceae family (Rubiacese) originating from the South Pacific Islands. Noni contains various nutrients, vitamins, minerals and active ingredients necessary for the human body. The main components include polysaccharides, phenols, flavonoids, terpenes, scopolamine, terpenoids, alkaloids, anthraquinones, flavonoid glycosides, iridoid glycosides, rutin, phytosterols, etc. Noni has the functions of anti-allergy, anti-oxidation, anti-virus, anti-tumor, enhancing immunity, reducing cardiovascular diseases, etc. It can prevent and treat a variety of diseases, such as skin diseases, wound infections, diabetes, hypertension, heart disease, mental depression, etc.

[0003] Since Noni has a wide range of nutritional and medicinal values, Noni health products have been widely developed in the market. Noni is mostly processed into Noni juice, fruit powder and puree for sale. In the process of processing into products, a large amount of pomace will be produced. As a waste, Noni pomace is not well utilized at present. In addition to pectin and fiber, Noni pomace also contains a large amount of phenolic and ketone substances. Therefore, using Noni pomace to extract polyphenols and other useful ingredients to produce Noni polyphenols can turn waste into treasure, which can not only increase the economic added value of Noni fruit, but also realize the comprehensive utilization value of Noni fruit, and reduce environmental pollution.

[0004] Regarding the extraction of polyphenols, currently, organic solvent extraction method (without extraction pressure) or high temperature method are widely used. However, these methods will mostly lead to the loss of active ingredients in Noni pomace during the extraction process, and the extraction rate is low. Summary of the invention

[0005] The purpose of the present invention is to provide a noni polyphenol and an extraction method thereof, so as to efficiently extract the noni polyphenol from noni pomace, improve the extraction efficiency of the noni polyphenol, and the extracted noni polyphenol has high antioxidant activity.

[0006] The present invention provides a method for extracting Noni polyphenols, comprising the following steps:

[0007] Performing far infrared assisted pulse vacuum drying on the noni pomace to obtain dried noni pomace;

[0008] Performing airflow ultrafine grinding on the dried Noni pomace to obtain the Noni pomace powder;

[0009] Mixing the ethanol aqueous solution and the Noni pomace powder, extracting and collecting the extract; the extract contains Noni polyphenols;

[0010] The extraction times are 2 to 5 times, the extraction time for each time is 20 to 30 minutes, the temperature is 50 to 70° C., and the pressure is 5 to 10 MPa;

[0011] The volume concentration of ethanol in the ethanol aqueous solution is 50-80%.

[0012] Preferably, the moisture content of the Noni pomace powder is ≤12%.

[0013] Preferably, the particle size of the Noni pomace powder is 20 to 50 μm.

[0014] Preferably, the far-infrared assisted pulse vacuum drying has a vacuum holding time of 8 to 12 minutes, a vacuum pressure of 6 to 10 kPa, a normal pressure holding time of 5 to 9 minutes, a temperature of 48 to 56° C., a radiation power of 760 to 800 W, and a radiation distance of 10 to 20 cm.

[0015] Preferably, the classifier frequency of the airflow ultrafine grinding is 60Hz / 0.6A, the induced draft fan frequency is 40Hz / 7.2A, the grinding pressure is 0.7-0.9MPa, the grinding time is 4-8h, the feed airflow is 0.5-0.9MPa, and the grinding airflow is 0.7-0.9MPa.

[0016] Preferably, the mass volume ratio of the Noni pomace powder and water is 1 g: (5-20) mL.

[0017] Preferably, after obtaining the extract, the method further comprises: centrifuging the extract, collecting the supernatant and concentrating it to obtain the Noni polyphenols.

[0018] Preferably, the centrifugal force of the centrifugation is 4000-8000g, and the time is 5-10min.

[0019] Preferably, the concentration temperature is 37-45°C.

[0020] The present invention also provides Noni polyphenols obtained by the extraction method described in the above technical scheme; the Noni polyphenols include gallic acid 329.76±32.88μg / g, p-hydroxybenzoic acid 11.66±0.09μg / g, caffeic acid 16.67±0.02μg / g, rutin 59.72±32.43μg / g, scopoletin 50.82±1.40μg / g and quercetin 82.47±0.10μg / g.

[0021] Beneficial effects:

[0022] The invention provides a method for extracting noni polyphenols, wherein noni pomace is subjected to far-infrared assisted pulse vacuum drying to obtain dried noni pomace; the dried noni pomace is subjected to airflow ultrafine grinding to obtain the noni pomace powder; an ethanol aqueous solution and the noni pomace powder are mixed to extract and collect the extract; the extract contains noni polyphenols; the extraction is performed 2 to 5 times, the time of each extraction is 20 to 30 minutes, the temperature is 50 to 70°C, and the pressure is 5 to 10 MPa; the volume concentration of ethanol in the ethanol aqueous solution is 50 to 80%. The invention utilizes far-infrared assisted pulse vacuum drying technology to quickly dry noni pomace at a relatively low temperature, reduce the degradation of heat-sensitive components, and thus retain more active components; the airflow ultrafine grinding technology can further refine the dried noni pomace, increase the contact area between the solvent and the pomace in the extraction process, and promote the full release of polyphenols. The noni pomace powder is extracted with ethanol aqueous solution as solvent, and the extraction conditions are strictly limited, which improves the extraction efficiency of polyphenols. Compared with traditional extraction technology (organic solvent extraction method (without extraction pressure) or high temperature method), the polyphenol extraction rate can be increased by 5-10%. While avoiding environmental pollution, the by-products are utilized in a high-value manner. It has the advantages of high efficiency, energy saving and environmental protection, and can be used for large-scale industrial production. DETAILED DESCRIPTION

[0023] The present invention provides a method for extracting Noni polyphenols, comprising the following steps:

[0024] Performing far infrared assisted pulse vacuum drying on the noni pomace to obtain dried noni pomace;

[0025] Performing airflow ultrafine grinding on the dried Noni pomace to obtain the Noni pomace powder;

[0026] Mixing the ethanol aqueous solution and the Noni pomace powder, extracting and collecting the extract; the extract contains Noni polyphenols;

[0027] The extraction times are 2 to 5 times, the extraction time for each time is 20 to 30 minutes, the temperature is 50 to 70° C., and the pressure is 5 to 10 MPa;

[0028] The volume concentration of ethanol in the ethanol aqueous solution is 50-80%.

[0029] The invention performs far-infrared-assisted pulse vacuum drying on the noni pomace to obtain dried noni pomace.

[0030] In the present invention, as an embodiment, the moisture content of the dried Noni pomace is ≤12%; as another embodiment, the moisture content of the dried Noni pomace is 11%. As an embodiment, the vacuum holding time of the far-infrared assisted pulse vacuum drying is 8 to 12 minutes; as another embodiment, the vacuum holding time of the far-infrared assisted pulse vacuum drying is 10 minutes. As an embodiment, the vacuum pressure of the far-infrared assisted pulse vacuum drying is 6 to 10 kPa; as another embodiment, the vacuum pressure of the far-infrared assisted pulse vacuum drying is 8 kPa. As an embodiment, the normal pressure holding time of the far-infrared assisted pulse vacuum drying is 5 to 9 minutes; as another embodiment, the normal pressure holding time of the far-infrared assisted pulse vacuum drying is 7 minutes. As an embodiment, the temperature of the far-infrared assisted pulse vacuum drying is 48 to 56°C; as another embodiment, the temperature of the far-infrared assisted pulse vacuum drying is 52°C. As an embodiment, the radiation power of the far-infrared assisted pulse vacuum drying is 760-800W; as another embodiment, the radiation power of the far-infrared assisted pulse vacuum drying is 780W. As an embodiment, the radiation distance of the far-infrared assisted pulse vacuum drying is 10-20cm; as another embodiment, the radiation distance of the far-infrared assisted pulse vacuum drying is 15cm. The present invention utilizes far-infrared assisted pulse vacuum drying to dry the noni pomace, which can further retain the active ingredients in the noni pomace while effectively removing excess water in the noni pomace, creating favorable conditions for the subsequent extraction of noni polyphenols.

[0031] The present invention has no strict requirements on the source of the Noni pomace, and it can be obtained by conventional methods in the art, for example, by washing the waste Noni pomace generated during the processing of Noni juice and Noni wine with clean water.

[0032] After obtaining the dried Morinda citrifolia pomace, the present invention performs airflow ultrafine grinding on the dried Morinda citrifolia pomace to obtain Morinda citrifolia pomace powder.

[0033] In the present invention, as an embodiment, the water content of the Noni pomace powder is ≤12%; as another embodiment, the water content of the Noni pomace powder is 11%. As an embodiment, the particle size of the Noni pomace powder is 20-50 μL; as another embodiment, the particle size of the Noni pomace powder is 30 μL.

[0034] In the present invention, as an embodiment, the classifier frequency of the airflow ultrafine pulverization is 55-65Hz / 0.5-0.7A; as another embodiment, the classifier frequency of the airflow ultrafine pulverization is 60Hz / 0.6A. As an embodiment, the induced draft fan frequency of the airflow ultrafine pulverization is 35-45Hz / 7-7.4A; as another embodiment, the induced draft fan frequency of the airflow ultrafine pulverization is 40Hz / 7.2A. As an embodiment, the pulverization pressure of the airflow ultrafine pulverization is 0.7-0.9MPa; as another embodiment, the pulverization pressure of the airflow ultrafine pulverization is 0.9MPa. As an embodiment, the pulverization time of the airflow ultrafine pulverization is 4-8h; as another embodiment, the pulverization time of the airflow ultrafine pulverization is 8h. As an embodiment, the feed airflow of the airflow ultrafine pulverization is 0.5-0.9MPa; as another embodiment, the feed airflow of the airflow ultrafine pulverization is 0.7MPa. As an embodiment, the airflow of the airflow ultrafine grinding is 0.7-0.9MPa; as another embodiment, the airflow of the airflow ultrafine grinding is 0.8MPa. The present invention uses airflow ultrafine grinding technology to refine the dried Noni pomace, further increasing the contact area between the solvent and the pomace in the extraction process, and promoting the full release of polyphenols.

[0035] After obtaining the noni pomace powder, the present invention mixes the ethanol aqueous solution with the noni pomace powder, extracts and collects the extract; the extract contains noni polyphenols.

[0036] In the present invention, as an embodiment, the volume concentration of ethanol in the ethanol aqueous solution is 50-80%; as another embodiment, the volume concentration of ethanol in the ethanol aqueous solution is 60-70%. As an embodiment, the volume ratio of the Noni pomace powder to water is 1g: (5-20) mL; as another embodiment, the volume ratio of the Noni pomace powder to water is 1g: (10-15) mL; as another embodiment, the volume ratio of the Noni pomace powder to water is 1g: 12 mL.

[0037] In the present invention, as an embodiment, the number of extractions is 2 to 5 times; as another embodiment, the number of extractions is 3 to 4 times; as another embodiment, the number of extractions is 3 times. As an embodiment, the time for each extraction is 20 to 30 minutes; as another embodiment, the time for each extraction is 25 minutes. As an embodiment, the temperature for each extraction is 50 to 70°C; as another embodiment, the temperature for each extraction is 55 to 65°C; as another embodiment, the temperature for each extraction is 60°C. As an embodiment, the pressure for each extraction is 5 to 10 MPa; as another embodiment, the pressure for each extraction is 7 to 10 MPa; as another embodiment, the pressure for each extraction is 8 MPa.

[0038] The present invention uses ethanol aqueous solution as solvent, strictly controls parameters such as ethanol concentration, temperature, pressure and time, so as to ensure that while efficiently extracting polyphenols, its natural structure and biological activity are retained to the greatest extent; the polyphenol yield is significantly improved, which is higher than the traditional method, the production cost is reduced, and the environmental pollution is small. The results of the embodiment show that the extraction rate of the noni polyphenol obtained by the extraction method of the present invention reaches 344.50-369.25 μg / g, that is, 34.450%-36.925%, has obvious ABTS free radical scavenging ability and DPPH free radical scavenging ability, and has a certain iron ion reduction ability.

[0039] After obtaining the extract, the present invention preferably centrifuges the extract, collects the supernatant and concentrates it to obtain the Noni polyphenols.

[0040] In the present invention, as an embodiment, the centrifugal force of the centrifugation is 4000-8000g; as another embodiment, the centrifugal force of the centrifugation is 6000-8000g; as another embodiment, the centrifugal force of the centrifugation is 8000g. As an embodiment, the centrifugal time is 5-10min; as another embodiment, the centrifugal time is 7-10min; as another embodiment, the centrifugal time is 10min. As an embodiment, the concentration temperature is 37-45°C; as another embodiment, the concentration temperature is 40-45°C; as another embodiment, the concentration temperature is 43°C. The present invention centrifuges and concentrates the extract, which can remove solids such as noni pomace, thereby increasing the concentration of polyphenols.

[0041] The extraction method provided by the present invention makes full use of the noni pomace that will become waste, extracts noni polyphenols from the noni pomace, avoids environmental pollution and makes high-value use of by-products, has the advantages of low cost, environmental friendliness, short production cycle, etc., and is a method for extracting noni total polyphenols with broad application prospects.

[0042] The present invention also provides the noni polyphenol obtained by the extraction method described in the above technical scheme; the noni polyphenol includes gallic acid 329.76±32.88μg / g, p-hydroxybenzoic acid 11.66±0.09μg / g, caffeic acid 16.67±0.02μg / g, rutin 59.72±32.43μg / g, scopoletin 50.82±1.40μg / g and quercetin 82.47±0.10μg / g. The noni polyphenol provided by the present invention has obvious ABTS free radical scavenging ability and DPPH free radical scavenging ability, and has a certain iron ion reducing ability, has strong antioxidant activity, and the extraction rate reaches 344.50-369.25μg / g, that is, 34.450%-36.925%.

[0043] In order to further illustrate the present invention, a kind of Noni polyphenol and the extraction method thereof provided by the present invention are described in detail below in combination with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0044] Example 1

[0045] A method for extracting polyphenols from noni pomace based on rapid solvent extraction technology, comprising the following steps:

[0046] (1) Using the waste Noni pomace generated during the processing of Noni juice and Noni wine as raw material, washing with clean water, and drying the Noni pomace using far-infrared assisted pulse vacuum drying technology; wherein:

[0047] The vacuum holding time of pulse vacuum drying is 10 minutes, the vacuum pressure is 8 kPa, the normal pressure holding time is 7 minutes, the temperature of pulse vacuum drying is 52°C, the radiation power is 780 W, the radiation distance is 15 cm, and the moisture content of noni pomace after drying is 12%.

[0048] (2) The dried noni pomace is pulverized by airflow ultrafine pulverization technology; wherein the frequency of the ultrafine classifier is set to 60 Hz / 0.6A, the frequency of the induced draft fan is set to 40 Hz / 7.2A, the pulverization pressure is set to 0.9 MPa, the pulverization time is 8 h, the feed airflow is 0.7 MPa, and the pulverization airflow is 0.8 MPa.

[0049] (3) Using a rapid solvent extractor, water and ethanol were used as a composite solvent to extract polyphenols from the crushed noni pomace to obtain an extract; wherein the volume fraction of ethanol in the composite solvent was 65%, and the volume ratio of noni pomace to the composite solvent was 1:12; the extraction temperature was 60°C, the extraction pressure was 10 MPa, the extraction time was 25 min each time, and the number of cyclic extractions was 3 times.

[0050] (4) The extracted solution is centrifuged and filtered to obtain a supernatant, which is then concentrated to obtain the Noni polyphenol extract; the centrifugation conditions are: 8000g, 10min, and the concentration temperature is 43°C, and the solution is concentrated until the water is almost completely evaporated.

[0051] (5) Refer to the method of Wang Ruimin et al. (Wang Ruimin, Li Zhaohui, Zhao Fengnian, et al. Effects of different solvents on the composition spectrum, antioxidant capacity and antibacterial activity of polyphenols in noni seed extracts [J]. Food Science and Technology, 2021, 46(10), 169-176.). The composition and content of noni polyphenol compounds were determined by ultra-high performance liquid chromatography. Specifically: Agilent 1260 high performance liquid chromatograph was used for determination. Polyphenol chromatography conditions: ZORBAX SB-C18 column (5μm, 250mm×4.6mm); column temperature 30℃, DAD detector, detection wavelength 280nm, injection volume 10μL, flow rate 0.8mL / min, mobile phase A is acetonitrile, and mobile phase B is 0.1% formic acid water. Gradient elution program: 0-6 min, 15% A; 6-10 min, 20% A; 10-20 min, 25% A; 20-30 min, 35% A; 30-40 min, 50% A; 40-55 min, 80% A; 55-60 min, 15% A.

[0052] The obtained Noni polyphenols contained 358.26 μg / g of gallic acid, 11.70 μg / g of p-hydroxybenzoic acid, 16.67 μg / g of caffeic acid, 85.15 μg / g of rutin, 52.01 μg / g of scopoletin and 82.52 μg / g of quercetin.

[0053] Example 2

[0054] A method for extracting polyphenols from noni pomace based on rapid solvent extraction technology is the same as that of Example 1, except that during the extraction in step (3), the rapid solvent extraction technology is used, a rapid solvent extractor is used, and water and ethanol are used as a composite solvent to extract polyphenols from the crushed noni pomace to obtain an extract; wherein the volume fraction of ethanol in the composite solvent is 70%, and the volume ratio of noni pomace to the composite solvent is 1:10; the extraction temperature is 60°C, the extraction pressure is 10Mpa, the extraction time is 30min each time, and the number of cyclic extractions is 3 times.

[0055] The obtained Noni polyphenols contained 342.36 μg / g of gallic acid, 11.58 μg / g of p-hydroxybenzoic acid, 16.65 μg / g of caffeic acid, 69.67 μg / g of rutin, 50.92 μg / g of scopoletin and 82.37 μg / g of quercetin.

[0056] Comparative Example 1

[0057] A method for extracting polyphenols from noni pomace based on rapid solvent extraction technology is the same as Example 1, except that during the extraction in step (3), the extraction time for each extraction is 40 minutes.

[0058] Comparative Example 2

[0059] A method for extracting polyphenols from noni pomace based on rapid solvent extraction technology is the same as Example 1, except that during the extraction in step (3), the extraction temperature for each extraction is 100°C.

[0060] Comparative Example 3

[0061] A method for extracting polyphenols from noni pomace based on rapid solvent extraction technology is the same as Example 1, except that during the extraction in step (3), pure ethanol (98% v / v) is used instead of the composite solvent.

[0062] Comparative Example 4

[0063] A method for extracting polyphenols from noni pomace based on rapid solvent extraction technology is the same as Example 1, except that step (1) adopts a traditional hot air drying method and is dried at 55° C. for 8 hours.

[0064] Test Example 1

[0065] The yields of the noni polyphenols of Examples 1 to 2 and Comparative Examples 1 to 4 were compared by the Folin phenol method, the DPPH free radical scavenging ability, the ABTS free radical scavenging ability, and the iron ion reducing ability (the higher the absorbance value, the stronger the reducing ability) were determined, and the antioxidant activities of the noni polyphenols of Examples 1 to 2 and Comparative Examples 1 to 4 were determined. The results are shown in Table 1.

[0066] Among them, the determination method of ABTS free radical scavenging ability refers to the method of Qin et al. (Qin Y, Wang L, Liu YF, et al. Release of phenolics compounds from Rubus idaeus L. dried fruits and seeds during simulated in vitro digestion and their bio-activities [J]. Journal of Functional Foods, 2018, 46: 57-65.). 50 μL of noni polyphenol aqueous solution of different concentrations (0, 2, 4, 6, 8, 10 mg / mL) was added to the prepared ABTS solution (the absorbance at 734 nm was 0.7 ± 0.02), and the above solution was mixed evenly. The reaction was carried out in the dark at room temperature for 30 minutes, and ascorbic acid was used as a positive control;

[0067] The determination of DPPH free radical scavenging ability was based on the method of Zhu Huilan et al. (Zhu Huilan. Green extraction, separation and purification of phenolic substances from Noni leaves and their biological activity [D]. Hainan University, 2021.). 50 μL of Noni polyphenol aqueous solution of different concentrations (0, 2, 4, 6, 8, 10 mg / mL) was added to the prepared DPPH solution and shaken well. The reaction was carried out at room temperature and in the dark for 30 minutes, and then the absorbance at 734 nm was measured.

[0068] Ascorbic acid was used as a positive control;

[0069] The determination of iron ion reducing ability was based on the method of Huang Long et al. (Huang Long. Variety differences in phenolic substances and antioxidant activity of bitter melon and sweet corn and the effects of thermal processing on them [D]. Huazhong Agricultural University, 2011.). The FRAP working reagent was obtained by mixing 300mmoL / L acetate buffer (pH3.6), 10mmoL / L TPTZ (2,4,6-tripyridyl-s-triazine, solvent is 40mmoL HCL solution) and 20mmoL / LFeCl3 in a volume ratio of 10:1:1. This reagent needs to be heated to 37°C in a water bath before use. The specific determination process is: accurately aspirate 150μL of noni polysaccharide sample aqueous solution of different concentrations, add 2.85mL FRAP working solution respectively, protect from light for 30min at room temperature, and measure the absorbance value of each solution at a wavelength of 593nm.

[0070] Table 1 Yield and antioxidant capacity of noni polyphenols under different extraction methods

[0071] Samples to be tested Extraction rate (μg / g) ABTS(%) DPPH(%) Absorbance Example 1 <![CDATA[369.25 a ]]> <![CDATA[64.92 a ]]> <![CDATA[23.55 a ]]> <![CDATA[0.33 a ]]> Example 2 <![CDATA[344.50 a ]]> <![CDATA[63.95 a ]]> <![CDATA[23.68 a ]]> <![CDATA[0.29 b ]]> Comparative Example 1 <![CDATA[270.92 b ]]> <![CDATA[60.22 b ]]> <![CDATA[21.67 b ]]> <![CDATA[0.30 b ]]> Comparative Example 2 <![CDATA[194.47 c ]]> <![CDATA[55.13 c ]]> <![CDATA[18.66 c ]]> <![CDATA[0.24 c ]]> Comparative Example 3 <![CDATA[288.59 b ]]> <![CDATA[61.13 b ]]> <![CDATA[21.88 b ]]> <![CDATA[0.28 b ]]> Comparative Example 4 <![CDATA[108.29 d ]]> <![CDATA[49.23 d ]]> <![CDATA[10.81 d ]]> <![CDATA[0.09 d ]]>

[0072] Note: Different lowercase letters in the table indicate statistically significant differences, p<0.05.

[0073] It can be seen from Table 1 that the extraction rate of noni polyphenols in Examples 1 to 2 is significantly higher than that in Comparative Examples 1 to 4, and the noni polyphenols in Examples 1 to 2 have obvious ABTS free radical scavenging ability and DPPH free radical scavenging ability, and have a certain iron ion reducing ability, and have high antioxidant activity.

[0074] Based on the above content, it can be seen that the extraction method provided by the present invention uses less solvent and is time-saving, and can obtain uniform polyphenols from noni pomace with a yield higher than 15% and a purity of more than 90%. At the same time, the natural structure and biological activity of the polyphenols are retained, and the polyphenols have strong antioxidant activity.

[0075] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for extracting Noni polyphenols, characterized in that: The steps include: Performing far infrared assisted pulse vacuum drying on the noni pomace to obtain dried noni pomace; Performing airflow ultrafine grinding on the dried Noni pomace to obtain the Noni pomace powder; Mixing the ethanol aqueous solution and the Noni pomace powder, extracting and collecting the extract; the extract contains Noni polyphenols; The extraction times are 2 to 5 times, the extraction time for each time is 20 to 30 minutes, the temperature is 50 to 70° C., and the pressure is 5 to 10 MPa; The volume concentration of ethanol in the ethanol aqueous solution is 50-80%.

2. The extraction method according to claim 1, characterized in that The moisture content of the Noni pomace powder is ≤12%.

3. The extraction method according to claim 1, characterized in that The particle size of the Noni pomace powder is 20 to 50 μm.

4. The extraction method according to claim 1, characterized in that The far-infrared assisted pulse vacuum drying has a vacuum holding time of 8 to 12 minutes, a vacuum pressure of 6 to 10 kPa, a normal pressure holding time of 5 to 9 minutes, a temperature of 48 to 56° C., a radiation power of 760 to 800 W, and a radiation distance of 10 to 20 cm.

5. The extraction method according to claim 1, characterized in that The classifier frequency of the airflow ultrafine grinding is 60Hz / 0.6A, the induced draft fan frequency is 40Hz / 7.2A, the grinding pressure is 0.7-0.9MPa, the grinding time is 4-8h, the feed airflow is 0.5-0.9MPa, and the grinding airflow is 0.7-0.9MPa.

6. The extraction method according to claim 1, characterized in that The mass volume ratio of the Noni pomace powder and water is 1g: (5-20)mL.

7. The extraction method according to claims 1 to 6, characterized in that After obtaining the extract, the method further comprises: centrifuging the extract, collecting the supernatant and concentrating the extract to obtain the Noni polyphenols.

8. The extraction method according to claim 7, characterized in that The centrifugal force of the centrifugation is 4000-8000g, and the time is 5-10 minutes.

9. The extraction method according to claim 8, characterized in that The concentration temperature is 37-45°C.

10. Noni polyphenols obtained by the extraction method according to any one of claims 1 to 9; the Noni polyphenols include gallic acid 329.76±32.88μg / g, p-hydroxybenzoic acid 11.66±0.09μg / g, caffeic acid 16.67±0.02μg / g, rutin 59.72±32.43μg / g, scopoletin 50.82±1.40μg / g and quercetin 82.47±0.10μg / g.