A method of modifying cell wall material of a celery plant to increase its ability to adsorb polyphenols

Abstract

The application discloses a method for modifying cell wall material of celery to improve the adsorption capacity of the cell wall material to polyphenols. The method applies ultrasonic waves to the modification process of the cell wall material of the celery, and is used for adsorption and desorption of polyphenol substances. After different pectin components are removed, the adsorption capacity of the cell wall material of the celery is changed. The cell wall material of the celery after the pectin components are removed can effectively improve the adsorption capacity and desorption capacity of the polyphenols, and improve the purity of the polyphenols. Compared with the intact cell wall of the celery without the pectin components removed, the cell wall of the celery after the different pectin components are removed has improved adsorption capacity and desorption capacity to the polyphenols. In addition, after the intact cell wall of the celery and the cell wall of the celery after the pectin components are removed are adsorbed / desorbed, the purity of the polyphenols can be improved by about 5.4 times.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to a method for modifying celery cell wall materials to improve their ability to adsorb polyphenols. Background Technology

[0002] Phenolic compounds are compounds formed by replacing hydrogen atoms on the benzene ring of aromatic hydrocarbons with hydroxyl groups. They are secondary metabolites widely found in plants. Based on molecular weight, phenolic compounds can be divided into: monomeric phenols with a molecular weight below 500, including flavonoids (anthocyanins, flavonols, flavanols, etc.) and non-flavonoids (phenolic acids, stilbenes, etc.); compounds with a molecular weight between 500 and 3000 are tannins, which are further divided into hydrolyzed tannins and condensed tannins; and compounds with a molecular weight greater than 3000 are called polyflavonoids. Plant polyphenols play an important role in preventing aging, cardiovascular diseases, and neurodegenerative diseases. Natural polyphenols mainly come from plants, such as fruits and vegetables; therefore, the separation and purification of phenolic substances in fruits and vegetables is crucial. Existing methods for separating and purifying phenolic substances mainly include column chromatography, membrane separation, and high-performance preparative liquid chromatography, but each method has limitations in terms of extraction purity, purification efficiency, purification cost, scale, and environmental impact. Plant cell walls are mainly composed of macromolecules such as cellulose, hemicellulose, and pectin, which have been proven to be usable materials for polyphenol purification. The main source of plant cell walls is fruit and vegetable residues, making them widely available and inexpensive. Using fruit and vegetable cell wall materials for polyphenol purification represents a novel method with promising applications. Based on this, modifying plant cell walls to increase their adsorption capacity for polyphenols has become a new research direction.

[0003] In the prior art, patent CN201980001691.8 discloses a resin separation and purification method for grape polyphenols, including extracting polyphenol alkaline extract from lees using an alkaline solution, adsorbing the polyphenol components in the alkaline extract using NKA-9 or HPD600 macroporous resin, and finally eluting with ethanol to recover the grape polyphenols. While this method effectively obtains polyphenols from lees, the resin used is expensive and resin activation requires the use of organic reagents, making it unsuitable for low-cost, large-scale extraction of polyphenols in factories. Patent CN201810663012.0 discloses a purification method for tea polyphenols, including treating an adsorption column filled with expanded graphite, filling the treated adsorption column with tea extract and filtering to obtain a filtrate, and evaporating and vacuum drying the filtrate. Although this method yields tea polyphenols with high purity, it requires a large amount of organic reagents during extraction, has a long pretreatment time, and is highly polluting. Summary of the Invention

[0004] To address the problems of insufficient recovery of polyphenols from fruits and vegetables, high recovery costs, low efficiency, and underutilization of the adsorption function of fruit and vegetable cell walls in existing technologies, this invention provides a method for modifying celery cell wall materials to enhance their polyphenol adsorption capacity. This method can not only significantly improve the cell wall adsorption / desorption capacity but also shorten the adsorption time and increase the purity of polyphenols.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention protects a method for preparing modified celery cell wall material, which involves obtaining celery cell wall material from celery residue and modifying the extracted cell walls. The method mainly includes the following steps:

[0007] (1) Extraction of intact celery cell wall material:

[0008] The celery residue remaining after juicing is mixed with 90±5% ethanol aqueous solution at a material-to-liquid ratio of 1:3-8, preferably 5 (g / mL), and boiled. After boiling, the residue is filtered. The residue is then repeatedly mixed with 70±5% ethanol aqueous solution at a material-to-liquid ratio of 1:10-30, preferably 20 (g / mL), and allowed to stand and filter. Finally, the residue is freeze-dried and ground into granules to obtain intact celery cell wall material.

[0009] (2) Ultrasonic-assisted removal of water-soluble pectin:

[0010] The whole celery cell wall material was mixed with deionized water and placed in a low-temperature circulating tank. An ultrasonic probe was inserted for ultrasonic treatment. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered. The resulting filter residue was freeze-dried and ground into granules to obtain celery cell wall material with water-soluble pectin removed.

[0011] (3) Ultrasonic-assisted removal of chelated pectin:

[0012] Celery cell wall material with water-soluble pectin removed was mixed with CDTA solution containing 0.1±0.05mol / L CH3COOK and placed in a low-temperature circulating tank. An ultrasonic probe was inserted for ultrasonic treatment. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The resulting filter residue was freeze-dried and then ground into granules using a grinder to obtain celery cell wall material with water-soluble and chelating pectin removed.

[0013] (4) Ultrasonic-assisted removal of alkali-soluble pectin:

[0014] Celery cell wall material with water-soluble and chelated pectin removed was mixed with 0.05±0.03mol / L Na2CO3 solution and placed in a 4℃ low-temperature circulating tank. An ultrasonic probe was inserted for ultrasonic treatment, and then the mixture was placed in a 25℃ low-temperature circulating tank for ultrasonic treatment. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The resulting filter residue was freeze-dried and ground into granules to obtain celery cell wall material with water-soluble, chelated, and alkali-soluble pectin removed.

[0015] In the specific implementation plan, the low temperature is ≤25℃.

[0016] Secondly, the present invention also protects the modified celery cell wall material obtained by the method described above.

[0017] Thirdly, the present invention also protects the application of the modified celery cell wall material described above in the adsorption of polyphenols.

[0018] Specifically, the application includes the following steps:

[0019] (1) Adsorption of polyphenols:

[0020] Add the crude polyphenol extract and celery cell wall material to an Erlenmeyer flask at a material-to-liquid ratio of 1:100-300 (g / mL), and shake thoroughly to allow the celery cell wall material to fully adsorb the polyphenols.

[0021] (2) Desorption of polyphenols:

[0022] The adsorbed polyphenols and cell wall material were filtered, and the resulting celery cell wall material was added to a conical flask with a 50±5% ethanol aqueous solution at a material-to-liquid ratio of 1:100-300 (g / mL). The mixture was shaken thoroughly to allow the celery cell wall material to fully desorb the polyphenols.

[0023] Fourthly, this invention protects a method for modifying celery cell wall material to improve its polyphenol adsorption capacity. The method involves removing free sugars and free phenols from the celery residue remaining after juicing to obtain celery cell wall material. The extracted celery cell walls are then modified and used as adsorbents to adsorb and desorb polyphenols, thereby improving the adsorption and desorption capacity of the celery cell walls. The method includes the following steps:

[0024] (1) Extraction of intact celery cell wall material:

[0025] The celery residue remaining after juicing is mixed with 90±5% ethanol aqueous solution at a material-to-liquid ratio of 1:3-8, preferably 5 (g / mL), and boiled. After boiling, the residue is filtered. The residue is then repeatedly mixed with 70±5% ethanol aqueous solution at a material-to-liquid ratio of 1:10-30, preferably 20 (g / mL), and allowed to stand and filter. Finally, the residue is freeze-dried and ground into granules to obtain intact celery cell wall material.

[0026] (2) Ultrasonic-assisted removal of water-soluble pectin:

[0027] The whole celery cell wall material was mixed with deionized water and placed in a low-temperature circulating tank. An ultrasonic probe was inserted for ultrasonic treatment. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered. The resulting filter residue was freeze-dried and ground into granules to obtain celery cell wall material with water-soluble pectin removed.

[0028] (3) Ultrasonic-assisted removal of chelated pectin:

[0029] Celery cell wall material with water-soluble pectin removed was mixed with CDTA solution containing 0.1±0.05mol / L CH3COOK and placed in a low-temperature circulating tank. An ultrasonic probe was inserted for ultrasonic treatment. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The resulting filter residue was freeze-dried and then ground into granules using a grinder to obtain celery cell wall material with water-soluble and chelating pectin removed.

[0030] (4) Ultrasonic-assisted removal of alkali-soluble pectin:

[0031] Celery cell wall material with water-soluble and chelated pectin removed was mixed with 0.05±0.03mol / L Na2CO3 solution and placed in a 4℃ low-temperature circulating tank. An ultrasonic probe was inserted for ultrasonic treatment, and then the mixture was placed in a 25℃ low-temperature circulating tank for ultrasonic treatment. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The resulting filter residue was freeze-dried and ground into granules to obtain celery cell wall material with water-soluble, chelated, and alkali-soluble pectin removed.

[0032] (5) Adsorption of polyphenols:

[0033] Add the crude polyphenol extract and celery cell wall material to an Erlenmeyer flask at a material-to-liquid ratio of 1:100-300 (g / mL), and shake thoroughly to allow the celery cell wall material to fully adsorb the polyphenols.

[0034] (6) Desorption of polyphenols:

[0035] The adsorbed polyphenols and cell wall material were filtered, and the resulting celery cell wall material was added to a conical flask with a 50±5% ethanol aqueous solution at a material-to-liquid ratio of 1:100-300 (g / mL). The mixture was shaken thoroughly to allow the celery cell wall material to fully desorb the polyphenols.

[0036] The pectin component in cell wall materials can hinder the adsorption of polyphenols by the cell wall. Therefore, the modified celery cell wall, by removing pectin and increasing the proportion of components such as cellulose and hemicellulose, enhances its adsorption of polyphenols.

[0037] Scanning electron micrographs of intact celery cell walls, celery cell walls without water-soluble pectin, celery cell walls without water-soluble and chelated pectin, and celery cell walls without water-soluble, chelated, and alkali-soluble pectin are attached. Figure 1 As shown in the figure, the gradual removal of pectin increases the porosity and surface area of ​​the cell wall material, and the structural changes lead to an enhanced ability of the cell wall to adsorb polyphenols.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) This invention applies ultrasonic technology to the modification process of celery cell wall material, and then to the adsorption and desorption process of fruit and vegetable polyphenols. The composition of celery cell wall material is changed during the adsorption / desorption process, thereby increasing the adsorption and desorption of fruit and vegetable polyphenols by celery cell wall.

[0040] (2) After modifying the celery cell wall material, the phenolic substances were purified, which improved the purity of polyphenols. This method has low adsorbent cost, low energy consumption, and simple operation. It only uses inorganic reagents and ethanol, without using other organic reagents. Moreover, the ethanol can be recycled and reused. The operation process is green and pollution-free, making it an efficient and environmentally friendly method for purifying phenolic substances. Attached Figure Description

[0041] Figure 1 Scanning electron micrographs of intact celery cell walls (a), celery cell walls without water-soluble pectin (b), celery cell walls without water-soluble and chelated pectin (c), and celery cell walls without water-soluble, chelated, and alkali-soluble pectin (d).

[0042] Figure 2 Adsorption kinetics comparison between Example 1 and Comparative Examples 1-3.

[0043] Figure 3 Comparison of desorption kinetics between Example 1 and Comparative Examples 1-3.

[0044] Figure 4 Adsorption kinetics of Example 2 compared with those of Comparative Examples 4-6.

[0045] Figure 5 Comparison of desorption kinetics between Example 2 and Comparative Examples 4-6.

[0046] Figure 6 Adsorption kinetics of Example 3 compared with those of Comparative Examples 7-9.

[0047] Figure 7 Comparison of desorption kinetics between Example 3 and Comparative Examples 7-9. Detailed Implementation

[0048] The present invention will be further described in detail below with reference to the embodiments. Reagents or instruments used without a specified manufacturer are considered to be conventional products that can be purchased on the market.

[0049] On one hand, this invention provides a method for modifying celery cell wall material. Celery cell wall material is obtained by removing free sugars and free phenols from the celery residue remaining after juicing. The extracted celery cell walls are then modified and used as adsorbents to adsorb and desorb polyphenols, thereby improving the adsorption and desorption capacity of the celery cell walls. The method includes the following steps:

[0050] (1) Extraction of intact celery cell wall material:

[0051] The remaining celery residue after juicing was mixed with 90% ethanol aqueous solution at a ratio of 1:5 (g / mL) and boiled. The mixture was then filtered. The residue was repeatedly mixed with 70% ethanol aqueous solution at a ratio of 1:20 (g / mL), allowed to stand, and filtered. The resulting residue was freeze-dried at 10 Pa for 48 hours and then ground into granules using a grinder to obtain intact celery cell wall material.

[0052] (2) Ultrasonic-assisted removal of water-soluble pectin:

[0053] The whole celery cell wall material was mixed with deionized water and placed in a 25°C low-temperature circulating tank. An ultrasonic probe was inserted for ultrasonic treatment. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered. The resulting filter residue was freeze-dried at 10Pa for 48 hours and then ground into granules using a grinder to obtain celery cell wall material with water-soluble pectin removed.

[0054] (3) Ultrasonic-assisted removal of chelated pectin:

[0055] Celery cell wall material with water-soluble pectin removed was mixed with CDTA solution containing 0.1 mol / L CH3COOK (0.05 mol / L, pH=6.5) and placed in a 25℃ low-temperature circulating tank. An ultrasonic probe was inserted for ultrasonic treatment. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The resulting filter residue was freeze-dried at 10 Pa for 48 h and then ground into granules using a grinder to obtain celery cell wall material with water-soluble and chelating pectin removed.

[0056] (4) Ultrasonic-assisted removal of alkali-soluble pectin:

[0057] Celery cell wall material with water-soluble and chelated pectin removed was mixed with 0.05 mol / L Na2CO3 solution (containing 0.02 mol / L NaBH4) and placed in a 4°C low-temperature circulating tank. An ultrasonic probe was inserted for ultrasonic treatment, and then the mixture was placed in a 25°C low-temperature circulating tank for ultrasonic treatment. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The resulting filter residue was freeze-dried at 10 Pa for 48 h and then ground into granules using a grinder to obtain celery cell wall material with water-soluble, chelated, and alkali-soluble pectin removed.

[0058] (5) Preparation of crude extract of fruit and vegetable polyphenols:

[0059] The fruit and vegetable residues were extracted with 50% ethanol aqueous solution at a material-to-liquid ratio of 1:30 (g / mL) for 8 hours. The residues were filtered and the ethanol was removed by rotary evaporation. The resulting liquid was the crude polyphenol extract.

[0060] (6) Adsorption of polyphenols:

[0061] The crude polyphenol extract and celery cell wall material were added to an Erlenmeyer flask at a material-to-liquid ratio of 1:200 (g / mL). The mixture was shaken at 150 rpm for 30 min at 25°C in an orbital shaker to allow the celery cell wall material to fully adsorb the polyphenols.

[0062] (7) Desorption of polyphenols:

[0063] The adsorbed polyphenols and cell wall material were filtered, and the resulting celery cell wall material was added to a conical flask with a 50% ethanol aqueous solution at a material-to-liquid ratio of 1:200 (g / mL). The flask was shaken at 150 rpm for 10 min at 25°C in an orbital shaker to allow the celery cell wall material to fully desorb the polyphenols.

[0064] The ultrasonic power mentioned in steps (2)-(4) is 18W / cm. 2 The ultrasonic frequency is 20kHz.

[0065] The purpose of step (2) is to remove water-soluble pectin from the celery cell wall. The ratio of the intact celery cell wall material to the deionized water solution is 1:50 (g / mL), and the ultrasonic treatment time is 90 min.

[0066] The purpose of step (3) is to remove chelated pectin from the celery cell wall. The celery cell wall material for removing water-soluble pectin is mixed with a CDTA solution containing 0.1 mol / L CH3COOK (0.05 mol / L, pH=6.5) at a ratio of 1:150 (g / mL), and the ultrasonic treatment time is 6 h.

[0067] The purpose of step (4) is to remove alkali-soluble pectin from the celery cell wall. The ratio of the celery cell wall material for removing water-soluble and chelating pectin to the 0.05 mol / L Na2CO3 solution (containing 0.02 mol / L NaBH4) is 1:150 (g / mL). The ultrasonic treatment time is 16 h at 4℃ and 6 h at 25℃.

[0068] The following examples illustrate preferred embodiments of the present invention, but the present invention is not limited thereto.

[0069] Example 1

[0070] (1) Extraction of intact celery cell wall material: The celery residue remaining after juicing was mixed with 90% ethanol aqueous solution at a material-liquid ratio of 1:5 (g / mL), boiled, and filtered. The residue was repeatedly mixed with 70% ethanol aqueous solution at a material-liquid ratio of 1:20 (g / mL), allowed to stand, and filtered. The final residue was freeze-dried at 10 Pa for 48 h and then ground into granules using a grinder to obtain intact celery cell wall material.

[0071] (2) Ultrasonic-assisted removal of water-soluble pectin: Intact celery cell wall material was mixed with deionized water at a material-to-liquid ratio of 1:50 (g / mL) and placed in a 25℃ low-temperature circulating tank. An ultrasonic probe was inserted and the ultrasonic level was set at 18W / cm. 2 The cell wall material was subjected to ultrasonic treatment for 90 minutes at a power of 1000 kPa. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered. The resulting filter residue was freeze-dried at 10 Pa for 48 hours and then ground into granules using a grinder to obtain celery cell wall material with water-soluble pectin removed.

[0072] (3) Ultrasonic-assisted removal of chelated pectin: Celery cell wall material with water-soluble pectin removed was mixed with a CDTA solution (0.05 mol / L, pH = 6.5) containing 0.1 mol / L CH3COOK at a material-to-liquid ratio of 1:150 (g / mL) and placed in a 25℃ low-temperature circulating bath. An ultrasonic probe was inserted and the ultrasonic level was set at 18 W / cm. 2 The cell wall material was subjected to ultrasonic treatment at a power of 6 hours. The obtained cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The obtained filter residue was freeze-dried at 10 Pa for 48 hours and then ground into granules using a grinder to obtain celery cell wall material with water-soluble and chelated pectin removed.

[0073] (4) Ultrasonic-assisted removal of alkali-soluble pectin: Celery cell wall material from which water-soluble and chelated pectin have been removed was mixed with 0.05 mol / L Na2CO3 solution (containing 0.02 mol / L NaBH4) at a material-to-liquid ratio of 1:150 (g / mL). The mixture was then placed in a 4℃ low-temperature circulating bath, and ultrasonic treatment was performed for 16 hours at 80% power using an ultrasonic probe. Afterward, the mixture was placed in a 25℃ low-temperature circulating bath at 18 W / cm². 2 The cell wall material was subjected to ultrasonic treatment at a power of 6 hours. The obtained cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The obtained filter residue was freeze-dried at 10 Pa for 48 hours and then ground into granules using a grinder to obtain celery cell wall material with water-soluble, chelating, and alkali-soluble pectin removed.

[0074] (5) Preparation of crude extract of fruit and vegetable polyphenols: Blueberry residue was extracted with 50% ethanol aqueous solution at a material-to-liquid ratio of 1:30 (g / mL) for 8 hours, the residue was filtered, and the ethanol was removed by rotary evaporation. The resulting liquid was the crude extract of blueberry polyphenols.

[0075] (6) Adsorption of polyphenols: Add the crude blueberry polyphenol extract and celery cell wall material to a conical flask at a ratio of 1:200 (g / mL). Shake at 150 rpm for 30 min at 25°C in an orbital shaker so that the celery cell wall material can fully adsorb blueberry polyphenols.

[0076] (7) Desorption of polyphenols: The adsorbed blueberry polyphenols and cell wall material were filtered, and the resulting celery cell wall material and 50% ethanol aqueous solution were added to a conical flask at a material-to-liquid ratio of 1:200 (g / mL). The mixture was shaken at 150 rpm for 10 min at 25°C in an orbital shaker to allow the celery cell wall material to fully desorb the blueberry polyphenols.

[0077] Example 2

[0078] (1) Extraction of intact celery cell wall material: The celery residue remaining after juicing was mixed with 90% ethanol aqueous solution at a material-liquid ratio of 1:5 (g / mL), boiled, and filtered. The residue was repeatedly mixed with 70% ethanol aqueous solution at a material-liquid ratio of 1:20 (g / mL), allowed to stand, and filtered. The final residue was freeze-dried at 10 Pa for 48 h and then ground into granules using a grinder to obtain intact celery cell wall material.

[0079] (2) Ultrasonic-assisted removal of water-soluble pectin: Intact celery cell wall material was mixed with deionized water at a material-to-liquid ratio of 1:50 (g / mL) and placed in a 25℃ low-temperature circulating tank. An ultrasonic probe was inserted and the ultrasonic level was set at 18W / cm. 2The cell wall material was subjected to ultrasonic treatment for 90 minutes at a power of 1000 kPa. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered. The resulting filter residue was freeze-dried at 10 Pa for 48 hours and then ground into granules using a grinder to obtain celery cell wall material with water-soluble pectin removed.

[0080] (3) Ultrasonic-assisted removal of chelated pectin: Celery cell wall material with water-soluble pectin removed was mixed with a CDTA solution (0.05 mol / L, pH = 6.5) containing 0.1 mol / L CH3COOK at a material-to-liquid ratio of 1:150 (g / mL) and placed in a 25℃ low-temperature circulating bath. An ultrasonic probe was inserted and the ultrasonic level was set at 18 W / cm. 2 The cell wall material was subjected to ultrasonic treatment at a power of 6 hours. The obtained cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The obtained filter residue was freeze-dried at 10 Pa for 48 hours and then ground into granules using a grinder to obtain celery cell wall material with water-soluble and chelated pectin removed.

[0081] (4) Ultrasonic-assisted removal of alkali-soluble pectin: Celery cell wall material from which water-soluble and chelated pectin have been removed was mixed with 0.05 mol / L Na2CO3 solution (containing 0.02 mol / L NaBH4) at a material-to-liquid ratio of 1:150 (g / mL). The mixture was then placed in a 4℃ low-temperature circulating bath, and ultrasonic treatment was performed for 16 hours at 80% power using an ultrasonic probe. Afterward, the mixture was placed in a 25℃ low-temperature circulating bath at 18 W / cm². 2 The cell wall material was subjected to ultrasonic treatment at a power of 6 hours. The obtained cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The obtained filter residue was freeze-dried at 10 Pa for 48 hours and then ground into granules using a grinder to obtain celery cell wall material with water-soluble, chelating, and alkali-soluble pectin removed.

[0082] (5) Preparation of crude extract of fruit and vegetable polyphenols: Grape residue was extracted with 50% ethanol aqueous solution at a material-to-liquid ratio of 1:30 (g / mL) for 8 hours, the residue was filtered, and the ethanol was removed by rotary evaporation. The resulting liquid was crude extract of grape polyphenols.

[0083] (6) Adsorption of polyphenols: Grape polyphenol crude extract and celery cell wall material were added to an Erlenmeyer flask at a material-to-liquid ratio of 1:200 (g / mL). The mixture was shaken at 150 rpm for 30 min at 25°C in an orbital shaker so that the celery cell wall material could fully adsorb grape polyphenols.

[0084] (7) Desorption of polyphenols: The adsorbed grape polyphenols and cell wall material were filtered, and the resulting celery cell wall material was added to a conical flask with 50% ethanol aqueous solution at a ratio of 1:200 (g / mL). The flask was shaken at 150 rpm for 10 min at 25°C in an orbital shaker so that the celery cell wall material could fully desorb the grape polyphenols.

[0085] Example 3

[0086] (1) Extraction of intact celery cell wall material: The celery residue remaining after juicing was mixed with 90% ethanol aqueous solution at a material-liquid ratio of 1:5 (g / mL), boiled, and filtered. The residue was repeatedly mixed with 70% ethanol aqueous solution at a material-liquid ratio of 1:20 (g / mL), allowed to stand, and filtered. The final residue was freeze-dried at 10 Pa for 48 h and then ground into granules using a grinder to obtain intact celery cell wall material.

[0087] (2) Ultrasonic-assisted removal of water-soluble pectin: Intact celery cell wall material was mixed with deionized water at a material-to-liquid ratio of 1:50 (g / mL) and placed in a 25℃ low-temperature circulating tank. An ultrasonic probe was inserted and the ultrasonic level was set at 18W / cm. 2 The cell wall material was subjected to ultrasonic treatment for 90 minutes at a power of 1000 kPa. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered. The resulting filter residue was freeze-dried at 10 Pa for 48 hours and then ground into granules using a grinder to obtain celery cell wall material with water-soluble pectin removed.

[0088] (3) Ultrasonic-assisted removal of chelated pectin: Celery cell wall material with water-soluble pectin removed was mixed with a CDTA solution (0.05 mol / L, pH = 6.5) containing 0.1 mol / L CH3COOK at a material-to-liquid ratio of 1:150 (g / mL) and placed in a 25℃ low-temperature circulating bath. An ultrasonic probe was inserted and the ultrasonic level was set at 18 W / cm. 2 The cell wall material was subjected to ultrasonic treatment at a power of 6 hours. The obtained cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The obtained filter residue was freeze-dried at 10 Pa for 48 hours and then ground into granules using a grinder to obtain celery cell wall material with water-soluble and chelated pectin removed.

[0089] (4) Ultrasonic-assisted removal of alkali-soluble pectin: Celery cell wall material from which water-soluble and chelated pectin have been removed was mixed with 0.05 mol / L Na2CO3 solution (containing 0.02 mol / L NaBH4) at a material-to-liquid ratio of 1:150 (g / mL). The mixture was then placed in a 4℃ low-temperature circulating bath, and ultrasonic treatment was performed for 16 hours at 80% power using an ultrasonic probe. Afterward, the mixture was placed in a 25℃ low-temperature circulating bath at 18 W / cm². 2 The cell wall material was subjected to ultrasonic treatment at a power of 6 hours. The obtained cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The obtained filter residue was freeze-dried at 10 Pa for 48 hours and then ground into granules using a grinder to obtain celery cell wall material with water-soluble, chelating, and alkali-soluble pectin removed.

[0090] (5) Preparation of crude extract of fruit and vegetable polyphenols: Celery residue was extracted with 50% ethanol aqueous solution at a material-to-liquid ratio of 1:30 (g / mL) for 8 hours, the residue was filtered, and the ethanol was removed by rotary evaporation. The resulting liquid was the crude extract of celery polyphenols.

[0091] (6) Adsorption of polyphenols: The crude extract of celery polyphenols and celery cell wall material were added to an Erlenmeyer flask at a ratio of 1:200 (g / mL). The mixture was shaken at 150 rpm for 30 min at 25°C in an orbital shaker so that the celery cell wall material could fully adsorb celery polyphenols.

[0092] (7) Desorption of polyphenols: The adsorbed celery polyphenols and cell wall material were filtered, and the resulting celery cell wall material and 50% ethanol aqueous solution were added to a conical flask at a material-to-liquid ratio of 1:200 (g / mL). The mixture was shaken at 150 rpm for 10 min at 25°C in an orbital shaker to allow the celery cell wall material to fully desorb the celery polyphenols.

[0093] Comparative Example 1: Intact celery cell walls without pectin removal adsorb blueberry polyphenols.

[0094] Except for not removing the pectin, the remaining steps are the same as in Example 1, except that the intact celery cell wall material without removing the pectin is used for adsorption and desorption.

[0095] Comparative Example 2: Celery cell walls with water-soluble pectin removed adsorbed blueberry polyphenols

[0096] Except for not removing chelating and alkali-soluble pectin, the remaining steps are the same as in Example 1, except that celery cell wall material with only water-soluble pectin removed is used for adsorption and desorption.

[0097] Comparative Example 3: Celery cell walls with removed water-soluble and chelating pectin adsorbed blueberry polyphenols

[0098] Except for not removing alkali-soluble pectin, the remaining steps are the same as in Example 1, except that celery cell wall material with only water-soluble and chelating pectin removed is used for adsorption and desorption.

[0099] Comparative Example 4: Adsorption of grape polyphenols by intact celery cell walls without pectin removal

[0100] Except for not removing the pectin, the remaining steps are the same as in Example 2, except that the intact celery cell wall material without removing the pectin is used for adsorption and desorption.

[0101] Comparative Example 5: Celery cell walls with removed water-soluble pectin adsorbed with grape polyphenols

[0102] Except for not removing chelating and alkali-soluble pectin, the remaining steps are the same as in Example 2, except that celery cell wall material with only water-soluble pectin removed is used for adsorption and desorption.

[0103] Comparative Example 6: Celery cell walls with removed water-soluble and chelating pectin adsorbed with grape polyphenols

[0104] Except for not removing alkali-soluble pectin, the remaining steps are the same as in Example 2, except that celery cell wall material with only water-soluble and chelating pectin removed is used for adsorption and desorption.

[0105] Comparative Example 7: Adsorption of celery polyphenols by intact celery cell walls without pectin removal

[0106] Except for not removing the pectin, the remaining steps are the same as in Example 3, except that the intact celery cell wall material without removing the pectin is used for adsorption and desorption.

[0107] Comparative Example 8: Celery cell walls with removed water-soluble pectin adsorbed celery polyphenols

[0108] Except for not removing chelating and alkali-soluble pectin, the remaining steps are the same as in Example 3, except that celery cell wall material with only water-soluble pectin removed is used for adsorption and desorption.

[0109] Comparative Example 9: Celery cell walls adsorbing celery polyphenols after removal of water-soluble and chelating pectin.

[0110] Except for not removing alkali-soluble pectin, the remaining steps are the same as in Example 3, except that celery cell wall material with only water-soluble and chelating pectin removed is used for adsorption and desorption.

[0111] Table 1. Comparison of polyphenol purity after water bath adsorption / desorption between Example 1 and Comparative Examples 1-3

[0112] Processing group Polyphenol purity (%) Before purification 9.3±0.2b intact celery cell walls 59.7±3.6a Celery cell walls with water-soluble pectin removed 60.5±2.5a Celery cell walls with water-soluble and chelated pectin removed 61.0±3.3a Celery cell walls with water-soluble, chelated, and alkali-soluble pectin removed. 60.1±2.8a

[0113] Table 2 Comparison of polyphenol purity after water bath adsorption / desorption between Example 2 and Comparative Examples 4-6

[0114] Processing group Polyphenol purity (%) Before purification 9.3±0.2b intact celery cell walls 60.2±1.5a Celery cell walls with water-soluble pectin removed 60.3±2.2a Celery cell walls with water-soluble and chelated pectin removed 61.7±2.7a Celery cell walls with water-soluble, chelated, and alkali-soluble pectin removed. 61.2±1.9a

[0115] Table 3 Comparison of polyphenol purity after water bath adsorption / desorption between Example 4 and Comparative Examples 7-9

[0116] Processing group Polyphenol purity (%) Before purification 9.3±0.2b intact celery cell walls 59.9±2.8a Celery cell walls with water-soluble pectin removed 61.6±1.4a Celery cell walls with water-soluble and chelated pectin removed 62.2±0.9a Celery cell walls with water-soluble, chelated, and alkali-soluble pectin removed. 61.7±0.6a

[0117] As shown in Table 1-3, the purity of polyphenols before adsorption / desorption purification was only 9.31%. However, after purification of celery cell wall materials with different treatments, the purity of polyphenols was significantly increased to about 60%, indicating that celery cell wall materials with different modifications can effectively and rapidly improve the purity of polyphenols.

[0118] Depend on Figure 2-7 It can be seen that removing pectin from the celery cell wall can effectively increase both the adsorption and desorption amounts.

[0119] Taking the adsorption of blueberry polyphenols as an example, when adsorption equilibrium is reached, the adsorption equilibrium adsorption capacity of intact celery cell wall material for blueberry polyphenols is 34.80 mg / g, the adsorption equilibrium adsorption capacity of celery cell wall material after removing water-soluble pectin is 50.60 mg / g, the adsorption equilibrium adsorption capacity of celery cell wall material after removing water-soluble and chelated pectin is 57.43 mg / g, and the adsorption equilibrium adsorption capacity of celery cell wall material after removing water-soluble, chelated and alkali-soluble pectin is as high as 69.08 mg / g.

[0120] After adsorption equilibrium was reached, the cell wall samples were desorbed. At desorption equilibrium, the desorption amount of blueberry polyphenols from intact celery cell wall material was 26.69 mg / g, the desorption amount of blueberry polyphenols from celery cell wall material after removing water-soluble pectin was 32.51 mg / g, the desorption amount of blueberry polyphenols from celery cell wall material after removing water-soluble and chelated pectin was 37.47 mg / g, and the desorption amount of blueberry polyphenols from celery cell wall material after removing water-soluble, chelated, and alkali-soluble pectin was 46.03 mg / g.

[0121] The equilibrium adsorption and desorption rates of grape polyphenols and celery polyphenols by celery cell wall materials showed the same pattern as those for adsorption of blueberry polyphenols.

[0122] The embodiments of the present invention have been described in detail above, but these are merely examples for ease of understanding and should not be considered as limiting the scope of the present invention. Similarly, any person skilled in the art can make various possible equivalent changes or substitutions based on the technical solutions and preferred embodiments described in the present invention, but all such changes or substitutions should fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a material to modify the cell wall of celery, characterized in that, Celery cell wall material is obtained from celery residue, and the extracted cell walls are modified. The method mainly includes the following steps: (1) Extraction of intact celery cell wall material: After juicing, the remaining celery residue was mixed with 90±5% ethanol aqueous solution at a ratio of 1g:3~8mL and boiled. The mixture was then filtered. The residue was repeatedly mixed with 70±5% ethanol aqueous solution at a ratio of 1g:10~30mL, allowed to stand, and filtered. The resulting residue was freeze-dried and then ground into granules to obtain intact celery cell wall material. (2) Ultrasonic-assisted removal of water-soluble pectin: The whole celery cell wall material was mixed with deionized water and placed in a low-temperature circulating tank. An ultrasonic probe was inserted for ultrasonic treatment. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered. The resulting filter residue was freeze-dried and ground into granules to obtain celery cell wall material with water-soluble pectin removed. (3) Ultrasonic-assisted removal of chelated pectin: Celery cell wall material with water-soluble pectin removed was mixed with CDTA solution containing 0.1±0.05 mol / L CH3COOK and placed in a low-temperature circulating tank. An ultrasonic probe was inserted for ultrasonic treatment. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The resulting filter residue was freeze-dried and then ground into granules using a grinder to obtain celery cell wall material with water-soluble and chelating pectin removed. (4) Ultrasonic-assisted removal of alkali-soluble pectin: Celery cell wall material with water-soluble and chelating pectin removed was mixed with 0.05±0.03 mol / L Na2CO3 solution and placed in a 4 ℃ low-temperature circulating tank. An ultrasonic probe was inserted for ultrasonic treatment, and then the mixture was placed in a 25 ℃ low-temperature circulating tank for ultrasonic treatment. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The resulting filter residue was freeze-dried and ground into granules to obtain celery cell wall material with water-soluble, chelating, and alkali-soluble pectin removed.

2. The method according to claim 1, characterized in that, In steps (2) to (4), the ultrasonic intensity is 18 W / cm. 2 The ultrasonic frequency is 20 kHz.

3. The method according to claim 1, characterized in that, In step (2), the ratio of intact celery cell wall material to deionized water solution is 1g:50mL, and the ultrasonic treatment time is 90min.

4. The method according to claim 1, characterized in that, In step (3), the ratio of celery cell wall material with water-soluble pectin removed to CDTA solution containing 0.1 mol / L CH3COOK is 1 g: 150 mL, and the ultrasonic treatment time is 6 h.

5. The method according to claim 1, characterized in that, In step (4), the ratio of celery cell wall material with water-soluble and chelating pectin removed to 0.05 mol / L Na2CO3 solution is 1g:150mL, and the ultrasonic treatment time is 16 h at 4℃ and 6 h at 25℃.

6. The method according to claim 1, characterized in that, The low temperature is ≤25℃.

7. The method according to claim 1, characterized in that, The specific steps for extracting intact celery cell wall material in step (1) are as follows: the celery residue remaining after juicing is mixed with 90±5% ethanol aqueous solution at a material-to-liquid ratio of 1g:5mL, boiled, and filtered. The filter residue is repeatedly mixed with 70±5% ethanol aqueous solution at a material-to-liquid ratio of 1g:10~30mL, allowed to stand, and filtered. Finally, the filter residue is freeze-dried and ground into granules to obtain intact celery cell wall material.

8. The method according to claim 1, characterized in that, The specific steps for extracting intact celery cell wall material in step (1) are as follows: The remaining celery residue after juicing is mixed with 90±5% ethanol aqueous solution at a material-to-liquid ratio of 1g:3~8mL, boiled, and filtered. The filter residue is repeatedly mixed with 70±5% ethanol aqueous solution at a material-to-liquid ratio of 1g:20mL, allowed to stand, and filtered. Finally, the filter residue is freeze-dried and ground into granules to obtain intact celery cell wall material.

9. The modified celery cell wall material obtained by the method of any one of claims 1-8.

10. The application of the modified celery cell wall material according to claim 9 as an adsorbent in the adsorption and desorption of polyphenols.

11. The application according to claim 10, characterized in that, The specific steps include the following: (1) Adsorption of polyphenols: Add the crude polyphenol extract and the modified celery cell wall material to an Erlenmeyer flask at a ratio of 1g:100~300mL, and shake thoroughly to allow the modified celery cell wall material to fully adsorb the polyphenols. (2) Desorption of polyphenols: The adsorbed polyphenols were filtered with the modified celery cell wall material. The resulting modified celery cell wall material with adsorbed polyphenols was added to a conical flask with a 50±5% ethanol aqueous solution at a material-to-liquid ratio of 1g:100~300mL. The mixture was shaken thoroughly to allow the modified celery cell wall material to fully desorb the polyphenols.

12. A method for modifying celery cell wall materials to improve their polyphenol adsorption capacity, characterized in that, Celery cell wall material is obtained by removing free sugars and free phenols from the celery residue remaining after juicing. The extracted celery cell walls are modified and used as adsorbents to adsorb and desorb polyphenols, thereby improving the adsorption and desorption capacity of the celery cell walls. The method includes the following steps: (1) Extraction of intact celery cell wall material: After juicing, the remaining celery residue was mixed with 90±5% ethanol aqueous solution at a ratio of 1g:3~8mL and boiled. The mixture was then filtered. The residue was repeatedly mixed with 70±5% ethanol aqueous solution at a ratio of 1g:10~30mL, allowed to stand, and filtered. The resulting residue was freeze-dried and then ground into granules to obtain intact celery cell wall material. (2) Ultrasonic-assisted removal of water-soluble pectin: The whole celery cell wall material was mixed with deionized water and placed in a low-temperature circulating tank. An ultrasonic probe was inserted for ultrasonic treatment. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered. The resulting filter residue was freeze-dried and ground into granules to obtain celery cell wall material with water-soluble pectin removed. (3) Ultrasonic-assisted removal of chelated pectin: Celery cell wall material with water-soluble pectin removed was mixed with CDTA solution containing 0.1±0.05 mol / L CH3COOK and placed in a low-temperature circulating tank. An ultrasonic probe was inserted for ultrasonic treatment. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The resulting filter residue was freeze-dried and then ground into granules using a grinder to obtain celery cell wall material with water-soluble and chelating pectin removed. (4) Ultrasonic-assisted removal of alkali-soluble pectin: Celery cell wall material with water-soluble and chelating pectin removed was mixed with 0.05±0.03 mol / L Na2CO3 solution and placed in a 4 ℃ low-temperature circulating tank. An ultrasonic probe was inserted for ultrasonic treatment, and then the mixture was placed in a 25 ℃ low-temperature circulating tank for ultrasonic treatment. The resulting cell wall material was repeatedly mixed with deionized water, allowed to stand, and filtered until the filtrate was neutral. The resulting filter residue was freeze-dried and ground into granules to obtain celery cell wall material with water-soluble, chelating, and alkali-soluble pectin removed. (5) Adsorption of polyphenols: Add the crude polyphenol extract and the modified celery cell wall material to an Erlenmeyer flask at a ratio of 1g:100~300mL, and shake thoroughly to allow the modified celery cell wall material to fully adsorb the polyphenols. (6) Desorption of polyphenols: The adsorbed polyphenols were filtered with the modified celery cell wall material. The resulting modified celery cell wall material with adsorbed polyphenols was added to a conical flask with a 50±5% ethanol aqueous solution at a material-to-liquid ratio of 1g:100~300mL. The mixture was shaken thoroughly to allow the modified celery cell wall material to fully desorb the polyphenols.

13. The method for modifying celery cell wall material to improve its polyphenol adsorption capacity according to claim 12, characterized in that, The specific steps for extracting intact celery cell wall material in step (1) are as follows: the celery residue remaining after juicing is mixed with 90±5% ethanol aqueous solution at a material-to-liquid ratio of 1g:5mL, boiled, and filtered. The filter residue is repeatedly mixed with 70±5% ethanol aqueous solution at a material-to-liquid ratio of 1g:10~30mL, allowed to stand, and filtered. Finally, the filter residue is freeze-dried and ground into granules to obtain intact celery cell wall material.

14. The method for improving the polyphenol adsorption capacity of celery cell wall material according to claim 12, characterized in that, The specific steps for extracting intact celery cell wall material in step (1) are as follows: The remaining celery residue after juicing is mixed with 90±5% ethanol aqueous solution at a material-to-liquid ratio of 1g:3~8mL, boiled, and filtered. The filter residue is repeatedly mixed with 70±5% ethanol aqueous solution at a material-to-liquid ratio of 1g:20mL, allowed to stand, and filtered. Finally, the filter residue is freeze-dried and ground into granules to obtain intact celery cell wall material.

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