Low-sugar and low-acid cranberry proanthocyanidin extract for female urinary comfort care and preparation method thereof

Abstract

The present invention discloses a low-sugar and low-acid cranberry proanthocyanidin extract for female urinary comfort care and a preparation method thereof. Dried and pulverized complete mature fruits of large cranberry are subjected to two-stage mild extraction with a 45-55% ethanol aqueous solution at pH 3.0-4.0 and 35-45°C. After ethanol recovery under reduced pressure, the resulting cranberry concentrate is sequentially treated with a microfiltration membrane, a 15-25 kDa ultrafiltration membrane, and a 400-600 Da nanofiltration membrane. The nanofiltration retentate is further subjected to diafiltration nanofiltration, vacuum belt drying, pulverization, and sieving to obtain the extract. The method does not involve separation of juice, peel, and pulp, enzymolysis, ultra-high-pressure extraction, adsorption resin, ion-exchange resin, or column chromatography. The extract has reduced sugar and organic acid contents, low water activity, good storage stability, and in vitro performance in reducing adhesion of uropathogenic Escherichia coli.

Description

[0001] DESCRIPTION

[0002] Low-Sugar and Low-Acid Cranberry Proanthocyanidin Extract for Female Urinary Comfort Care and Preparation Method Thereof Technical Field

[0003] The present invention belongs to the technical field of plant extracts and preparation of nutritional food raw materials, and particularly relates to a low-sugar and low-acid cranberry proanthocyanidin extract for female urinary comfort care and a preparation method thereof.

[0004] Background Art

[0005] Cranberry, also known as large cranberry, contains proanthocyanidins, anthocyanins, flavonols, organic acids and other polyphenolic components in its fruits. Cranberry extract is commonly used in foods for supporting female urinary health, dietary supplements and health food raw materials. Proanthocyanidins are among the important characteristic components of cranberry extract, and are commonly used as a quality control indicator for cranberry raw materials for supporting urinary health.

[0006] Existing cranberry extracts mostly use total proanthocyanidin content or total polyphenol content as the main quality indicator, and the preparation methods often involve acidic extraction with high-concentration ethanol, enrichment with macroporous adsorption resin, column chromatography purification, membrane separation and enrichment of fruit juice, solvent precipitation, or compounding with other functional components. Although such methods can obtain cranberry polyphenol extracts having a certain content, the following problems remain when the extracts are used in oral products for female urinary comfort care:

[0007] First, under strongly acidic or long-time high-alcohol extraction conditions, some cranberry proanthocyanidins and anthocyanin components are prone toDESCRIPTION

[0008] degradation or structural changes, resulting in insufficient batch-to-batch stability of the extract;

[0009] Second, ordinary cranberry extract liquids contain relatively high levels of sugars, organic acids and small-molecule impurities, and the extract obtained by direct drying is prone to moisture absorption and caking, thereby affecting storage stability and formulation compatibility;

[0010] Third, processes using macroporous adsorption resin, ion-exchange resin or column chromatography involve steps such as resin pretreatment, adsorption and desorption, solvent consumption and regeneration control, and have many process control points;

[0011] Fourth, some cranberry enrichment processes use cranberry juice or cranberry juice components as starting raw materials, which require relatively complicated raw-material pretreatment and make it difficult to reflect the comprehensive utilization of whole cranberry fruit raw materials;

[0012] Fifth, existing cranberry urinary-health products mostly compound cranberry extract with D-mannose, probiotics, phospholipids or other plant extracts, making it difficult to reflect the quality characteristics and functional correlation of cranberry extract itself in supporting female urinary health.

[0013] Therefore, it is necessary to provide a cranberry proanthocyanidin extract using complete mature fruits of large cranberry as raw material, having relatively low sugar and acid contents, low water activity and good storage stability, and a corresponding preparation method, so that the extract is suitable as a cranberry raw material for oral products for female urinary comfort care.

[0014] Summary of the InventionDESCRIPTION

[0015] In order to overcome the above defects of the prior art, the present invention provides a low-sugar and low-acid cranberry proanthocyanidin extract for female urinary comfort care and a preparation method thereof, thereby solving the problems in the prior art that cranberry extracts have degradation of active components caused by high-acid and high-alcohol extraction, moisture absorption and caking caused by high sugar and acid impurities, complicated resin processes, and difficulty in reflecting the urinary-health functional correlation of the raw material itself.

[0016] To achieve the above object, the present invention provides the following technical solutions:

[0017] A low-sugar and low-acid cranberry proanthocyanidin extract for female urinary comfort care and a preparation method thereof comprise the following steps:

[0018] (1) taking dried and pulverized complete mature fruits of large cranberry, adding a 45-55% by volume ethanol aqueous solution, adjusting the pH to 3.0-4.0, stirring and extracting at 35-45°C for 60-120 min at a solid-liquid ratio of 1 g:8-10 mL, filtering, and collecting a first extract;

[0019] (2) adding a 45-55% by volume ethanol aqueous solution to the filter residue obtained in step (1), stirring and extracting at 35-45°C for 40-60 min, filtering, and collecting a second extract;

[0020] (3) combining the first extract and the second extract, recovering ethanol under reduced pressure at a temperature not higher than 42°C to obtain a cranberry concentrate having an ethanol content not higher than 10 vol%;

[0021] (4) sequentially treating the cranberry concentrate obtained in step (3) with a microfiltration membrane, an ultrafiltration membrane having a molecular weightDESCRIPTION

[0022] cut-off of 15-25 kDa and a nanofiltration membrane having a molecular weight cut-off of 400-600 Da, wherein the ultrafiltration permeate is collected and subjected to nanofiltration concentration, and a nanofiltration retentate is collected;

[0023] (5) adding purified water to the nanofiltration retentate obtained in step (4) for diafiltration nanofiltration, wherein the amount of purified water added is 1.0- 1.5 times the volume of the nanofiltration retentate, and collecting the nanofiltration retentate again after diafiltration nanofiltration to obtain a low-sugar and low-acid cranberry proanthocyanidin concentrate;

[0024] (6) subjecting the low-sugar and low-acid cranberry proanthocyanidin concentrate obtained in step (5) to vacuum belt drying under conditions of a vacuum degree of -0.08 to -0.10 MPa and a material temperature of 45-55°C, pulverizing and sieving to obtain the cranberry proanthocyanidin extract;

[0025] wherein the dried and pulverized complete mature fruits of large cranberry are not subjected to separation of juice, peel and pulp; the preparation method does not involve enzymolysis treatment or ultra-high-pressure extraction treatment, and does not use adsorption resin, ion-exchange resin or column chromatography treatment.

[0026] Preferably, in step (1), the ethanol aqueous solution has a volume fraction of 49-51%, the pH is 3.5-3.7, the extraction temperature is 39-41°C, the extraction time is 75-85 min, and the solid-liquid ratio is 1 g:8.8-9.2 mL; in step (2), the extraction time is 48-52 min.

[0027] Preferably, in step (4), the microfiltration membrane has a pore size of 0.20-0.30 pm, the ultrafiltration membrane has a molecular weight cut-off of 18-22 kDa, and the nanofiltration membrane has a molecular weight cut-off of 450-550 Da; preferably, the microfiltration membrane has a pore size of 0.22 pm, theDESCRIPTION

[0028] ultrafiltration membrane has a molecular weight cut-off of 20 kDa, and the nanofiltration membrane has a molecular weight cut-off of 500 Da.

[0029] Preferably, in step (1), a food-grade acid and / or a salt thereof is used to adjust the pH to 3.0-4.0; preferably, the food-grade acid and / or the salt thereof are citric acid and potassium citrate.

[0030] Preferably, in step (5), the amount of purified water added is 1.2 times the volume of the nanofiltration retentate.

[0031] Preferably, in step (6), the vacuum belt drying is carried out at a vacuum degree of -0.090 MPa and a material temperature of 50°C.

[0032] Preferably, in step (1), the complete mature fruits of large cranberry are obtained by pulverization after freeze drying or hot-air drying at 50-60°C.

[0033] Preferably, a low-sugar and low-acid cranberry proanthocyanidin extract has the following indexes on a dry basis:

[0034] the total proanthocyanidin content is 18.0-24.0 wt%;

[0035] the soluble sugar content is not higher than 8.0 wt%;

[0036] the titratable organic acid content is not higher than 6.0 wt%;

[0037] the total anthocyanin content is 0.8-2.5 wt%;

[0038] the moisture content is not higher than 5.0 wt%;

[0039] the water activity aw measured at 25°C is not greater than 0.25;

[0040] after being placed at 40°C and a relative humidity of 75% for 30 days, the total proanthocyanidin retention rate is not lower than 86.0%.

[0041] Preferably, the extract is prepared by the preparation method of a low-sugar and low- acid cranberry proanthocyanidin extract for female urinary comfort care.

[0042] Preferably, the low-sugar and low-acid cranberry proanthocyanidin extract is used in the preparation of an oral product for female urinary comfort care.DESCRIPTION

[0043] Technical effects and advantages of the low-sugar and low-acid cranberry proanthocyanidin extract for female urinary comfort care and the preparation method thereof according to the present invention are as follows:

[0044] 1. The invention uses dried and pulverized complete mature fruits of large cranberry as raw material, does not carry out separation of juice, peel and pulp, and does not add D-mannose, probiotics, phospholipids, dandelion or other plant extracts, thereby highlighting the quality characteristics of cranberry extract itself and its correlation with female urinary health support.

[0045] 2. The invention uses a 45-55% by volume ethanol aqueous solution and performs two-stage mild extraction under conditions of pH 3.0-4.0 and 35-45°C, which is beneficial for reducing the influence of strong acidity (pH 1.0-3.0) and long-time high-alcohol extraction (65-85% ethanol, 4-6 h) on the stability of cranberry proanthocyanidins and anthocyanin components.

[0046] 3. The invention treats the cranberry extract liquid by a combined membrane fractionation mode of microfiltration, ultrafiltration and nanofiltration. Suspended impurities are removed by microfiltration, colloids and macromolecular pectin are removed by ultrafiltration, and sugars, organic acids and small-molecule impurities are reduced by nanofiltration and diafiltration nanofiltration, thereby obtaining a low-sugar and low-acid cranberry proanthocyanidin concentrate. Compared with a method in the prior art that treats fruit juice with multistage ultrafiltration membranes having molecular weight cut-offs from 160000 Da to 1000 Da, the present invention uses a membrane combination of ultrafiltration (15-25 kDa) and nanofiltration (400-600 Da), which can more effectively retain proanthocyanidins and remove small-molecule sugars and organic acids.

[0047] 4. The invention obtains a powdered cranberry proanthocyanidin extract byDESCRIPTION

[0048] low-temperature vacuum belt drying, without the need to add an exogenous carrier or functional compound raw material. The obtained extract has relatively low moisture and relatively low water activity, and can still maintain good total proanthocyanidin retention and powder fluidity under accelerated storage conditions.

[0049] 5. The extract obtained by the invention exhibits in vitro performance in reducing the relative adhesion rate in a model of adhesion of uropathogenic Escherichia coli to T24 bladder epithelial cells, and is suitable as a cranberry raw material for oral products for female urinary comfort care.

[0050] Brief Description of the Drawings

[0051] Fig. 1 is a flow chart of the low-sugar and low-acid cranberry proanthocyanidin extract for female urinary comfort care and the preparation method thereof proposed by the present invention.

[0052] Detailed Description

[0053] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort shall fall within the protection scope of the present invention.

[0054] It should be noted that, herein, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms comprising, including, orDESCRIPTION

[0055] any other variations thereof are intended to cover a non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising ..." does not exclude the presence of another same element in the process, method, article or device comprising the element.

[0056] Referring to Fig. 1, the present invention provides a low-sugar and low-acid cranberry proanthocyanidin extract for female urinary comfort care and a preparation method thereof. The preparation method comprises: taking dried and pulverized complete mature fruits of large cranberry, adding a 45-55% by volume ethanol aqueous solution, adjusting the pH to 3.0-4.0, stirring and extracting at 35-45°C for 60-120 min at a solid-liquid ratio of 1 g:8-10 mL, and filtering to collect a first extract; adding again a 45-55% by volume ethanol aqueous solution to the filter residue, stirring and extracting at 35-45°C for 40-60 min, and filtering to collect a second extract; combining the two extracts and recovering ethanol under reduced pressure at a temperature not higher than 42°C until the ethanol content is not higher than 10 vol%; sequentially treating the resulting concentrate with a microfiltration membrane, an ultrafiltration membrane having a molecular weight cut-off of 15-25 kDa and a nanofiltration membrane having a molecular weight cut-off of 400-600 Da, collecting the ultrafiltration permeate for nanofiltration concentration and collecting a nanofiltration retentate; adding purified water in an amount of 1.0- 1.5 times the volume of the nanofiltration retentate for diafiltration nanofiltration and then collecting the retentate again to obtain a low-sugar and low-acid cranberry proanthocyanidin concentrate; andDESCRIPTION

[0057] finally performing vacuum belt drying under conditions of a vacuum degree of -0.08 to -0.10 MPa and a material temperature of 45-55°C, followed by pulverizing and sieving to obtain the extract. The method uses complete mature fruits of large cranberry that have not been subjected to separation of juice, peel and pulp as raw material, does not carry out enzymolysis treatment or ultra-high-pressure extraction treatment, and does not use adsorption resin, ion-exchange resin or column chromatography treatment. On a dry basis, the obtained low-sugar and low-acid cranberry proanthocyanidin extract has a total proanthocyanidin content of 18.0-24.0 wt%, a soluble sugar content not higher than 8.0 wt%, a titratable organic acid content not higher than 6.0 wt%, a total anthocyanin content of 0.8-2.5 wt%, a moisture content not higher than 5.0 wt%, a water activity aw at 25°C not greater than 0.25, and a total proanthocyanidin retention rate not lower than 86.0% after being placed at 40°C and a relative humidity of 75% for 30 days. The extract can be applied to the preparation of oral products for female urinary comfort care.

[0058] Raw Material Description:

[0059] The fruits of large cranberry are food-grade mature cranberry fruits, with the scientific name Vaccinium macrocarpon Ait. The fruits are dried and pulverized after cleaning and removal of obvious impurities.

[0060] The ethanol is food-grade ethanol.

[0061] Citric acid, potassium citrate and purified water are all food-grade or food-processing-suitable raw materials.

[0062] Detection Methods:

[0063] The total proanthocyanidin content is determined by the BL-DMAC method, calculated as proanthocyanidin A2.DESCRIPTION

[0064] The total anthocyanin content is determined by the pH differential method, calculated as cyanidin-3-glucoside.

[0065] The soluble sugar content is determined by high-performance liquid chromatography, calculated as the total of glucose, fructose and sucrose.

[0066] The titratable organic acid content is determined by acid-base titration, calculated as citric acid.

[0067] The moisture content is determined by loss on drying at 105°C.

[0068] The water activity is measured with a water activity meter at 25 °C.

[0069] Ethanol residue is determined by gas chromatography.

[0070] The powder sieving pass rate is determined using a 20-mesh standard sieve. The uropathogenic Escherichia coli adhesion evaluation is performed using a T24 bladder epithelial cell model.

[0071] Example 1

[0072] Complete mature fruits of large cranberry were taken, freeze-dried, pulverized and passed through a 30-mesh sieve to obtain dried and pulverized complete mature fruits of large cranberry.

[0073] 10.0 kg of the dried and pulverized complete mature fruits of large cranberry were weighed, 90 L of a 50% by volume ethanol aqueous solution was added, the pH was adjusted to 3.6 with citric acid and potassium citrate, and extraction was performed with stirring at 40°C for 80 min. The mixture was filtered, and a first extract was collected.

[0074] 85 L of a 50% by volume ethanol aqueous solution was added to the filter residue, extraction was performed with stirring at 40°C for 50 min, the mixture was filtered, and a second extract was collected.

[0075] The first extract and the second extract were combined, and ethanol wasDESCRIPTION

[0076] recovered under reduced pressure at a temperature not higher than 42°C to obtain a cranberry concentrate having an ethanol content of 8.6 vol%.

[0077] The obtained cranberry concentrate was treated with a microfiltration membrane having a pore size of 0.22 pm, and the microfiltration permeate was collected. The microfiltration permeate was treated with an ultrafiltration membrane having a molecular weight cut-off of 20 kDa, and the ultrafiltration permeate was collected. The ultrafiltration permeate was treated with a nanofiltration membrane having a molecular weight cut-off of 500 Da, and the nanofiltration retentate was collected.

[0078] Purified water in an amount of 1.2 times the volume of the nanofiltration retentate was added to the obtained nanofiltration retentate for diafiltration nanofiltration. After diafiltration nanofiltration, the nanofiltration retentate was collected again to obtain a low-sugar and low-acid cranberry proanthocyanidin concentrate.

[0079] The low-sugar and low-acid cranberry proanthocyanidin concentrate was subjected to vacuum belt drying at a vacuum degree of -0.090 MPa and a material temperature of 50°C. After drying, the material was pulverized and passed through an 80-mesh sieve to obtain the low-sugar and low-acid cranberry proanthocyanidin extract for female urinary comfort care.

[0080] The obtained extract was a purplish-red to dark purplish-red powder having the characteristic odor of cranberry.

[0081] Example 2

[0082] This example was substantially the same as Example 1, except that:

[0083] In step (1), the ethanol aqueous solution had a volume fraction of 49%, the pHDESCRIPTION

[0084] was 3.7, the extraction temperature was 39°C, the extraction time was 85 min, and the solid-liquid ratio was 1 g:9.2 mL;

[0085] In step (2), the extraction temperature was 39°C and the extraction time was 52 min;

[0086] In step (4), the ultrafiltration membrane had a molecular weight cut-off of 22 kDa, and the nanofiltration membrane had a molecular weight cut-off of 550 Da;

[0087] In step (5), during diafiltration nanofiltration, the amount of purified water added was 1.3 times the volume of the nanofiltration retentate;

[0088] In step (6), the vacuum degree for vacuum belt drying was -0.088 MPa, and the material temperature was 48°C.

[0089] The obtained extract was a purplish-red powder having the characteristic odor of cranberry.

[0090] Example 3

[0091] This example was substantially the same as Example 1, except that:

[0092] In step (1), the ethanol aqueous solution had a volume fraction of 51%, the pH was 3.5, the extraction temperature was 41 °C, the extraction time was 75 min, and the solid-liquid ratio was 1 g:8.8 mL;

[0093] In step (2), the extraction temperature was 41 °C and the extraction time was 48 min;

[0094] In step (4), the ultrafiltration membrane had a molecular weight cut-off of 18 kDa, and the nanofiltration membrane had a molecular weight cut-off of 450 Da;

[0095] In step (5), during diafiltration nanofiltration, the amount of purified water added was 1.1 times the volume of the nanofiltration retentate;

[0096] In step (6), the vacuum degree for vacuum belt drying was -0.092 MPa, and the material temperature was 52°C.DESCRIPTION

[0097] The obtained extract was a dark purplish-red powder having the characteristic odor of cranberry.

[0098] Comparative

[0099] Example 1

[0100] This comparative example differs from Example 1 in that the extraction solvent was a 75% by volume ethanol aqueous solution, the pH was adjusted to 2.0, the extraction temperature was 50°C, and the extraction time was 4 h; microfiltration, ultrafiltration, nanofiltration and diafiltration nanofiltration treatments were not carried out, and low-temperature vacuum drying was directly performed after concentration under reduced pressure. The remaining conditions were the same as those in Example 1.

[0101] Comparative

[0102] Example 2

[0103] This comparative example differs from Example 1 in that ultrafiltration treatment was not carried out, and the microfiltration permeate was directly subjected to nanofiltration and diafiltration nanofiltration treatment. The remaining conditions were the same as those in Example 1.

[0104] Comparative

[0105] Example 3

[0106] This comparative example differs from Example 1 in that nanofiltration and diafiltration nanofiltration treatments were not carried out, and the ultrafiltration permeate was directly concentrated and then subjected to low-temperature vacuum drying. The remaining conditions were the same as those in Example 1.

[0107] Comparative

[0108] Example 4DESCRIPTION

[0109] This comparative example differs from Example 1 in that diafiltration nanofiltration treatment was not carried out, and the nanofiltration retentate was directly subjected to low-temperature vacuum drying. The remaining conditions were the same as those in Example 1.

[0110] Experimental Example 1

[0111] Evaluation of basic quality indicators of the extracts.

[0112] The cranberry extracts obtained in Examples 1-3 and Comparative Examples 1-4 were taken, and the total proanthocyanidin content, soluble sugar content, titratable organic acid content, total anthocyanin content, moisture content, water activity and ethanol residue were respectively measured.

[0113] Each sample was measured in parallel three times, and the data in Table 1 are average values.

[0114] Table 1 Basic Quality Indicators of the Extracts

[0115] TOTAL SOLUBL TITRATAB TOTAL MOISTU WATER ETHAN PROANTH E LE ANTHORE ACTIVIT OL SAMPLE 0- SUGAR ORGANIC CYANIN

[0116] CONTEN Y RESIDE CYANIDIN CONTE ACID CONTE T AW E CONTENT NT CONTENT NT

[0117] 6.4 1.5 0.05 Example 1 21.3% 5.1% 3.9% 0.21

[0118] % % % 6.8 1.6 0.06 Example 2 20.8% 5.3% 4.1% 0.22

[0119] % % % 6.1 1.4 0.05 Example 3 21.7% 4.9% 3.8% 0.21

[0120] % % % Comparati

[0121] 13.6 0.8 0.08 ve 18.4% 8.5% 4.7% 0.29

[0122] % % % Example 1

[0123] Comparati 20.1% 7.2 5.6% 1.4 4.6% 0.27 0.06

[0124]

[0125] DESCRIPTION

[0126] TOTAL SOLUBL TITRATAB TOTAL MOISTU WATER ETHAN PROANTH E LE ANTHORE ACTIVIT OL SAMPLE 0- SUGAR ORGANIC CYANIN

[0127] CONTEN Y RESIDE CYANIDIN CONTE ACID CONTE T AW E CONTENT NT CONTENT NT

[0128] ve % % % Example 2

[0129] Comparati

[0130] 18.3 1.8 0.05 ve 17.2% 12.1% 5.2% 0.34

[0131] % % % Example 3

[0132] Comparati

[0133] 10.8 1.5 0.05 ve 20.7% 7.7% 4.5% 0.28

[0134] % % % Example 4

[0135]

[0136] As can be seen from Table 1, the cranberry extracts obtained in Examples 1-3 had a total proanthocyanidin content of 20.8-21.7%, a soluble sugar content of 6.1-6.8%, a titratable organic acid content of 4.9-5.3%, and a water activity of 0.21-0.22. Compared with the comparative examples, while maintaining the cranberry proanthocyanidin content, the extracts obtained in the examples had relatively low sugar and acid contents and relatively low water activity.

[0137] Comparative Example 1 used a relatively high ethanol concentration and relatively strong acidic conditions for long-time extraction, and both its total proanthocyanidin content and total anthocyanin content were lower than those of Example 1. Comparative Example 3 did not carry out nanofiltration and diafiltration nanofiltration treatment, and its soluble sugar content, titratable organic acid content and water activity were all significantly higher than those of Example 1. Comparative Example 4 did not carry out diafiltration nanofiltration treatment, and its degree of sugar and acid reduction was weaker than that of Example 1. The above results indicate that the mild extraction,DESCRIPTION

[0138] membrane-fractionation sugar and acid removal, and diafiltration nanofiltration treatment of the present invention are beneficial for obtaining a low-sugar, low-water-activity cranberry proanthocyanidin extract.

[0139] Experimental Example 2

[0140] Evaluation of accelerated storage stability.

[0141] The cranberry extracts obtained in Example 1 and Comparative Examples 1 -4 were placed under conditions of 40°C and a relative humidity of 75% for 30 days. After placement, the total proanthocyanidin content was detected, the appearance of the powder was observed, and the 20-mesh sieve pass rate was measured.

[0142] Each sample was measured in parallel three times, and the data in Table 2 are average values.

[0143] The total proanthocyanidin retention rate was calculated according to the following formula:

[0144] Total proanthocyanidin retention rate = total proanthocyanidin content after accelerated storage for 30 days / initial total proanthocyanidin content x 100%

[0145] Table 2 Accelerated Storage Stability Evaluation Results

[0146] TOTAL INITIAL TOTAL PROANTHO APPEAR TOTAL PROANTHO

[0147] 20-MES PROANTHO SAMPLE CYANIDIN ANCE H SIEVE CYANIDIN CONTENT AFTER 30 PASS RATE CYANIDIN RETENTION AFTER 30 DAYS

[0148] CONTENT RATE DAYS

[0149] Slight

[0150] moisture

[0151] Example 1 21.3% 18.7% 87.8% absorption, no 91.5% obvious hard

[0152] blocks

[0153]

[0154] DESCRIPTION

[0155] TOTAL INITIAL TOTAL PROANTHO APPEAR TOTAL PROANTHO

[0156] 20-MES PROANTHO SAMPLE CYANIDIN ANCE H SIEVE CYANIDIN CONTENT AFTER 30 PASS RATE CYANIDIN RETENTION AFTER 30 DAYS

[0157] CONTENT RATE DAYS

[0158] Comparativ

[0159] Slight

[0160] e 18.4% 14.4% 78.3% 78.6% agglomeration

[0161] Example 1

[0162] Comparativ

[0163] Slight

[0164] e 20.1% 16.9% 84.1% 82.0% agglomeration

[0165] Example 2

[0166] Obvious

[0167] Comparativ

[0168] moisture

[0169] e 17.2% 13.0% 75.6% 65.2% absorption and

[0170] Example 3

[0171] caking

[0172] Comparativ

[0173] Slight

[0174] e 20.7% 17.1% 82.6% 80.4% agglomeration

[0175] Example 4

[0176]

[0177] As can be seen from Table 2, after the cranberry extract obtained in Example 1 was placed under accelerated conditions of 40°C and a relative humidity of 75% for 30 days, the total proanthocyanidin retention rate was 87.8%, and the powder showed only slight moisture absorption without obvious hard blocks, with a 20-mesh sieve pass rate of 91.5%. Comparative Example 1 used long-time extraction with high acid and high alcohol, and the total proanthocyanidin retention rate after 30 days was lower than that of Example 1. Comparative Example 3 did not carry out nanofiltration and diafiltration nanofiltration treatment, and obvious moisture absorption and caking occurred after 30 days, with a significantly decreased 20-mesh sieve pass rate. Comparative Example 4 did not carry outDESCRIPTION

[0178] diafiltration nanofiltration treatment, and its storage stability was weaker than that of Example 1. The above results indicate that the process of the present invention helps improve the stability and powder fluidity of the cranberry proanthocyanidin extract under accelerated storage conditions.

[0179] Experimental Example 3

[0180] Evaluation of uropathogenic Escherichia coli adhesion.

[0181] A uropathogenic Escherichia coli adhesion model was established using T24 bladder epithelial cells. The cranberry extracts obtained in Example 1 and Comparative Examples 1-4 were taken after being placed at 40°C and a relative humidity of 75% for 30 days, and were respectively prepared into sample solutions having the same final total proanthocyanidin concentration. After centrifugation, the supernatants were taken for cell experiments.

[0182] T24 cells were seeded in a 24-well plate and cultured until a cell monolayer was formed. A uropathogenic Escherichia coli suspension and each sample supernatant were added and co-incubated. After incubation, non-adherent bacteria were washed away, the cells were lysed, and gradient dilution plating and counting were performed. Taking the adhesion amount of Escherichia coli in the blank model group as 100%, the relative adhesion rate of each sample group was calculated. Cell viability was detected by the CCK-8 method.

[0183] Three replicate wells were set for each group, and the data in Table 3 are average values.

[0184] The relative adhesion rate was calculated according to the following formula: Relative adhesion rate = number of adherent colonies in the sample group / number of adherent colonies in the blank model group x 100%

[0185] The adhesion reduction was calculated according to the following formula:DESCRIPTION

[0186] Adhesion reduction = 100% - relative adhesion rate

[0187] Table 3 Uropathogenic Escherichia coli Adhesion Evaluation Results FINAL TOTAL RELATIVE PROANTHOADHESION CELL SAMPLE ADHESION CYANIDIN REDUCTION VIABILITY RATE CONCENTRATION

[0188] Blank

[0189] — 100.0% — 96.5% Model Group

[0190] Example 1 25pg / mL 62.4% 37.6% 94.8% Comparative

[0191] 25pg / mL 72.6% 27.4% 94.0% Example 1

[0192] Comparative

[0193] 25pg / mL 68.4% 31.6% 94.2% Example 2

[0194] Comparative

[0195] 25pg / mL 77.3% 22.7% 93.5% Example 3

[0196] Comparative

[0197] 25pg / mL 70.1% 29.9% 94.1% Example 4

[0198]

[0199] As can be seen from Table 3, under the same final total proanthocyanidin concentration, the sample of Example 1 after accelerated placement could reduce the relative adhesion rate of uropathogenic Escherichia coli on the surface of T24 bladder epithelial cells, and no obvious decrease in cell viability was observed. The relative adhesion rates of Comparative Example 1, Comparative Example 3 and Comparative Example 4 were all higher than that of Example 1. The above results indicate that the low-sugar and low-acid cranberry proanthocyanidin extract obtained by the present invention still has good in vitro anti-adhesion performance after storage, and is suitable as a cranberry raw material for oral products supporting female urinary health.

[0200] The above are merely specific embodiments of the present application, andDESCRIPTION

[0201] the protection scope of the present application is not limited thereto. Any change or substitution that can be readily conceived by those skilled in the art within the technical scope disclosed in the present application shall be included within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

[0202] Finally: the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent substitution, improvement and the like made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

CLAIMS1. A preparation method of a low-sugar and low-acid cranberry proanthocyanidin extract for female urinary comfort care, characterized by comprising the following steps:(1) taking dried and pulverized complete mature fruits of large cranberry, adding a 45-55% by volume ethanol aqueous solution, adjusting the pH to 3.0-4.0, stirring and extracting at 35-45°C for 60-120 min at a solid-liquid ratio of 1 g:8-10 mL, filtering, and collecting a first extract;(2) adding a 45-55% by volume ethanol aqueous solution to the filter residue obtained in step (1), stirring and extracting at 35-45°C for 40-60 min, filtering, and collecting a second extract;(3) combining the first extract and the second extract, recovering ethanol under reduced pressure at a temperature not higher than 42°C to obtain a cranberry concentrate having an ethanol content not higher than 10 vol%;(4) sequentially treating the cranberry concentrate obtained in step (3) with a microfiltration membrane, an ultrafiltration membrane having a molecular weight cut-off of 15-25 kDa and a nanofiltration membrane having a molecular weight cut-off of 400-600 Da, wherein the ultrafiltration permeate is collected and subjected to nanofiltration concentration, and a nanofiltration retentate is collected;(5) adding purified water to the nanofiltration retentate obtained in step (4) for diafiltration nanofiltration, wherein the amount of purified water added is 1.0- 1.5 times the volume of the nanofiltration retentate, and collecting the nanofiltration retentate again after diafiltration nanofiltration to obtain a low-sugar and low-acid cranberry proanthocyanidin concentrate;(6) subjecting the low-sugar and low-acid cranberry proanthocyanidin concentrate obtained in step (5) to vacuum belt drying under conditions of aCLAIMSvacuum degree of -0.08 to -0.10 MPa and a material temperature of 45-55°C, pulverizing and sieving to obtain the cranberry proanthocyanidin extract;wherein the dried and pulverized complete mature fruits of large cranberry are not subjected to separation of juice, peel and pulp; the preparation method does not involve enzymolysis treatment or ultra-high-pressure extraction treatment, and does not use adsorption resin, ion-exchange resin or column chromatography treatment.

2. The preparation method of the low-sugar and low- acid cranberry proanthocyanidin extract for female urinary comfort care according to claim 1 , characterized in that, in step (1), the ethanol aqueous solution has a volume fraction of 49-51%, the pH is 3.5-3.7, the extraction temperature is 39-41°C, the extraction time is 75-85 min, and the solid-liquid ratio is 1 g:8.8-9.2 mL; and in step (2), the extraction time is 48-52 min.

3. The preparation method of the low-sugar and low-acid cranberry proanthocyanidin extract for female urinary comfort care according to claim 1, characterized in that, in step (4), the microfiltration membrane has a pore size of 0.20-0.30 pm, the ultrafiltration membrane has a molecular weight cut-off of 18-22 kDa, and the nanofiltration membrane has a molecular weight cut-off of 450-550 Da; preferably, the microfiltration membrane has a pore size of 0.22 pm, the ultrafiltration membrane has a molecular weight cut-off of 20 kDa, and the nanofiltration membrane has a molecular weight cut-off of 500 Da.

4. The preparation method of the low-sugar and low-acid cranberry proanthocyanidin extract for female urinary comfort care according to claim 1, characterized in that, in step (1), a food-grade acid and / or a salt thereof is used to adjust the pH to 3.0-4.0; preferably, the food-grade acid and / or the salt thereof areCLAIMScitric acid and potassium citrate.

5. The preparation method of the low-sugar and low-acid cranberry proanthocyanidin extract for female urinary comfort care according to claim 1 , characterized in that, in step (5), the amount of purified water added is 1.2 times the volume of the nanofiltration retentate.

6. The preparation method of the low-sugar and low-acid cranberry proanthocyanidin extract for female urinary comfort care according to claim 1, characterized in that, in step (6), the vacuum belt drying is carried out at a vacuum degree of -0.090 MPa and a material temperature of 50°C.

7. The preparation method of the low-sugar and low-acid cranberry proanthocyanidin extract for female urinary comfort care according to claim 1, characterized in that, in step (1), the complete mature fruits of large cranberry are obtained by pulverization after freeze drying or hot-air drying at 50-60°C.

8. A low-sugar and low-acid cranberry proanthocyanidin extract prepared by the method according to any one of claims 1 to 7, characterized in that, on a dry basis, the extract has the following indexes:the total proanthocyanidin content is 18.0-24.0 wt%;the soluble sugar content is not higher than 8.0 wt%;the titratable organic acid content is not higher than 6.0 wt%;the total anthocyanin content is 0.8-2.5 wt%;the moisture content is not higher than 5.0 wt%;the water activity aw measured at 25°C is not greater than 0.25;after being placed at 40°C and a relative humidity of 75% for 30 days, the total proanthocyanidin retention rate is not lower than 86.0%.

9. The low-sugar and low- acid cranberry proanthocyanidin extract accordingCLAIMSto claim 8, characterized in that the extract is prepared by the preparation method according to any one of claims 1 to 7.

10. Use of the low-sugar and low-acid cranberry proanthocyanidin extract according to claim 8 or 9 in the preparation of an oral product for female urinary comfort care.

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