Water extraction preparation method of lotus leaf extract

Abstract

The invention discloses a water extraction preparation method of a lotus leaf extract, and relates to the technical field of natural plant extraction, and the specific operation steps are as follows: dry lotus leaf crushing, weak acid extraction, enzymolysis, ultrasonic extraction, filtration, residue leaching, freeze drying and other steps. According to the comprehensive extraction process of the water extraction preparation method of the lotus leaf extract provided by the invention, the water solution is used as a medium, and through a combined treatment method of weak acid extraction, cellulase and xylanase composite enzymolysis and ultrasonic extraction, the extraction efficiency of effective components in lotus leaves is improved, and the extraction process is more green and safer; the lotus leaf extract prepared by the invention not only retains the natural fragrance of lotus leaves, but also is good in water solubility, safer and more environment-friendly, meets the requirements of the market on natural and healthy products, and has important significance for promoting the processing and application of the lotus leaf extract.

Description

Technical Field

[0001] The invention relates to the technical field of biochemistry and environmental science, and in particular to a water extraction preparation method of a lotus leaf extract. Background Art

[0002] In the rapid evolution of modern society, people's daily pace is accelerating, and the pressure of life and work is increasing, causing many individuals to be on the verge of sub-health. However, the public's awareness of personal health maintenance has increased significantly. People have begun to actively seek to improve their overall health by supplementing functional ingredients, especially those natural ingredients derived from animals and plants. This trend has not only been widely recognized, but also aroused people's great interest and attention in a healthy lifestyle.

[0003] Lotus leaf (Folium Nelumbinis) is the leaf of the lotus plant of the Nymphaeaceae family. In China's long history, lotus leaf has not only been used for medical treatment, but also cleverly integrated into the production of food and beverages. It is a plant material with both medicinal and edible properties. Lotus leaf contains rich natural bioactive ingredients, such as nuciferine, flavonoids and polyphenols, which give lotus leaf a variety of health benefits, including lipid-lowering and weight-loss, lowering blood pressure and clearing away heat and relieving summer heat. In view of this, the development of lotus leaf extracts rich in active ingredients using lotus leaf as raw material for use in health products and functional foods undoubtedly has a solid consumer base and market potential.

[0004] In the prior art, the extraction methods of lotus leaf active ingredients include heating reflux method, enzymolysis method and ultrasonic method. The enzymolysis method has mild reaction conditions and effectively promotes the release of active substances by destroying the plant cell wall. The ultrasonic method uses the cavitation effect of ultrasonic waves to destroy the plant cell wall and promote the extraction solvent to penetrate into the cell, thereby increasing the extraction efficiency. Despite this, single extraction methods generally have problems such as long extraction time and insufficient extraction rate. In the preparation of lotus leaf extract, commonly used extractants include water and organic reagents. Although the lotus leaf extract prepared by water extraction is not as good as organic reagents in extraction rate, compared with organic solvent extraction, water extraction is greener and safer, has better water solubility, and can better retain the natural fragrance of lotus leaves. Therefore, developing an efficient water extraction process to improve the extraction rate of lotus leaf active ingredients and the utilization rate of lotus leaves is of great significance for promoting the processing and application of lotus leaf extracts. This can not only improve the quality of the product, but also ensure its safety and environmental protection, and meet the market demand for natural and healthy products. Summary of the invention

[0005] In order to solve the above technical problems, a water extraction preparation method of lotus leaf extract is provided. This technical solution solves the above problems.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0007] A water extraction preparation method of lotus leaf extract, the specific operation steps are as follows:

[0008] S1. Grinding and sieving lotus leaves: Select dry lotus leaves without impurities, mildew or deterioration, use a grinder to grind them, and pass them through a 0-40 mesh sieve to obtain lotus leaf dry powder;

[0009] S2, weak acid extraction of dry powder: adding the lotus leaf dry powder prepared in step S1 to a weak acid aqueous solution, stirring and mixing to form an extraction system for extraction, and obtaining a lotus leaf extract after the extraction is completed;

[0010] S3, enzymatic hydrolysis treatment: adding the composite enzyme preparation to the lotus leaf extract obtained in step S2, stirring and mixing, and then performing composite enzymatic hydrolysis. After the enzymatic hydrolysis is completed, the whole system is an enzymatic hydrolysis mixed liquid;

[0011] S4, ultrasonic extraction: transferring the enzymatic hydrolysis mixture into an ultrasonic device for ultrasonic extraction, and obtaining an ultrasonic extraction mixture after the ultrasonic extraction is completed;

[0012] S5, filtration treatment of the mixed solution: filtering the ultrasonic extraction mixed solution obtained in step S4, filtering and separating the precipitate to obtain the lotus leaf pulp precipitate, and obtaining the filtrate to obtain the lotus leaf extract;

[0013] S6, soaking the residue: adding the lotus leaf precipitate obtained in step S5 into a small amount of clean water for soaking, filtering the precipitate after soaking, and obtaining lotus leaf residue precipitate and lotus leaf residue soaking liquid respectively;

[0014] S7, concentration and drying: the lotus leaf extract obtained in step S5 is combined with the lotus leaf residue obtained in step S6, and mixed evenly, and concentrated and freeze-dried to obtain a dry product, i.e., the lotus leaf extract.

[0015] Preferably, the weak acid in step S2 is one or both of edible acetic acid and citric acid;

[0016] Preferably, in step S2, the solid-liquid ratio of lotus leaf dry powder to weak acid aqueous solution is 1:70-1:100 (m / v), the amount of weak acid added is to adjust the pH of the extraction system to 5.0-6.0 using weak acid, the extraction temperature is 45-55° C., and the extraction time is 30-60 min;

[0017] Preferably, in step S3, the composite enzyme preparation is cellulase (100,000 U / g) and xylanase (290,000 U / g), the enzymolysis temperature is 45-55°C, and the enzymolysis time is 30-70 min;

[0018] More preferably, the enzymatic hydrolysis time is 30 to 50 min.

[0019] Preferably, the addition ratio of cellulase and xylanase in the composite enzyme preparation is 1:0.5 to 1:2, and the total addition amount of the two is 0.2 to 0.3% (g / g lotus leaf dry powder);

[0020] Preferably, the ultrasonic conditions in step S4 are ultrasonic frequency 30-40kHz, ultrasonic power 150-300W, ultrasonic time 30-50min, and temperature 40-70°C;

[0021] More preferably, the ultrasonic temperature is 60-70°C.

[0022] Preferably, in step S6, the ratio of lotus leaf pulp precipitate to clean water in the soaking residue is 1:1-1:2 (m / v), and the soaking time is 30-60 min.

[0023] Preferably, the content of nuciferine in the lotus leaf extract is 71.37-83.80 mg / g, the content of total flavonoids is 70.35-92.58 mg / g (calculated as rutin), and the content of total phenols is 22.80-31.85 mg / g (calculated as gallic acid).

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention provides a comprehensive extraction process for a water extraction preparation method of lotus leaf extract, which uses an aqueous solution as a medium, and a combined treatment method of weak acid extraction, cellulase and xylanase composite enzymatic hydrolysis and ultrasonic extraction, which not only improves the extraction efficiency of effective components in lotus leaves, but also makes the extraction process more green and safe. The lotus leaf extract prepared by the present invention not only retains the natural fragrance of lotus leaves, but also has good water solubility, is safer and more environmentally friendly, and meets the market demand for natural and healthy products. The present invention is of great significance for promoting the processing and application of lotus leaf extracts. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a flow chart of the water extraction preparation method of lotus leaf extract. DETAILED DESCRIPTION

[0027] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can imagine other obvious variations that also fall within the protection scope of the present invention.

[0028] Embodiment 1:

[0029] A water extraction preparation method of lotus leaf extract comprises the following steps:

[0030] S1. Select dry lotus leaves without impurities, mildew or deterioration, crush them with a grinder, and pass them through a 0-40 mesh sieve to obtain lotus leaf dry powder;

[0031] S2, adding the lotus leaf dry powder prepared above to an aqueous solution containing citric acid at a solid-liquid ratio of 1:100 (m / v), stirring and mixing to form an extraction system, and extracting at 45-55° C. and pH 5.0-6.0 for 30-60 min, and obtaining a lotus leaf extract after the extraction;

[0032] S3, adding a cellulase and xylanase complex enzyme preparation to the lotus leaf extract obtained above in a ratio of 1:1, stirring and mixing, and then performing complex enzymolysis at 45° C. for 30 minutes. After the enzymolysis is completed, the entire system is an enzymolysis mixed liquid;

[0033] S4, ultrasonic extraction: transfer the enzymatic hydrolysis mixture into an ultrasonic device, and ultrasonically extract for 30 min at an ultrasonic frequency of 30-40 kHz, an ultrasonic power of 150-300 W, and an ultrasonic temperature of 70°C, and obtain an ultrasonic extraction mixture after the ultrasonic treatment is completed;

[0034] S5, filtering: filtering the ultrasonic extraction mixed solution obtained above, filtering and separating the precipitate to obtain the lotus leaf precipitate, and the filtrate obtained is the lotus leaf extract;

[0035] S6, soaking the residue: adding the lotus leaf precipitate obtained in step S5 into a small amount of clean water for soaking, the ratio is 1:1 (m / v), and after soaking for 30 minutes, filtering the precipitate to obtain lotus leaf residue precipitate and lotus leaf residue soaking liquid respectively;

[0036] S7, concentration and drying: the lotus leaf extract obtained in step S5 and the lotus leaf residue obtained in step S6 are combined and mixed, and then concentrated and freeze-dried to obtain a dry product, i.e., the lotus leaf extract.

[0037] Embodiment 2:

[0038] A water extraction preparation method of lotus leaf extract comprises the following steps:

[0039] S1. Select dry lotus leaves without impurities, mildew or deterioration, crush them with a grinder, and pass them through a 10-40 mesh sieve to obtain lotus leaf dry powder;

[0040] S2, adding the lotus leaf dry powder prepared above to an aqueous solution containing edible acetic acid at a solid-liquid ratio of 1:100 (m / v), stirring and mixing to form an extraction system, and extracting at 45-55° C. and pH 5.5-6.0 for 40-60 min, and obtaining a lotus leaf extract after the extraction;

[0041] S3, adding a cellulase and xylanase complex enzyme preparation to the lotus leaf extract obtained above in a ratio of 2:1, stirring and mixing, and then performing complex enzymolysis at 50° C. for 30 minutes. After the enzymolysis is completed, the entire system is an enzymolysis mixed liquid;

[0042] S4, ultrasonic extraction: transfer the enzymatic hydrolysis mixture into an ultrasonic device, and ultrasonically extract for 30 minutes at an ultrasonic frequency of 35-40 kHz, an ultrasonic power of 200-300 W, and an ultrasonic temperature of 60°C, and obtain an ultrasonic extraction mixture after the ultrasonic treatment is completed;

[0043] S5, filtering: filtering the ultrasonic extraction mixed solution obtained above, filtering and separating the precipitate to obtain the lotus leaf precipitate, and the filtrate obtained is the lotus leaf extract;

[0044] S6, soaking the residue: adding the lotus leaf precipitate obtained in step S5 into a small amount of clean water for soaking, the ratio is 1:2 (m / v), and after soaking for 60 minutes, filtering the precipitate to obtain lotus leaf residue precipitate and lotus leaf residue soaking liquid respectively;

[0045] S7, concentration and drying: the lotus leaf extract obtained in step S5 and the lotus leaf residue obtained in step S6 are combined and mixed, and then concentrated and freeze-dried to obtain a dry product, i.e., the lotus leaf extract.

[0046] Embodiment 3:

[0047] A water extraction preparation method of lotus leaf extract comprises the following steps:

[0048] S1. Select dry lotus leaves without impurities, mildew or deterioration, crush them with a grinder, and pass them through a 10-30 mesh sieve to obtain lotus leaf dry powder;

[0049] S2, adding the lotus leaf dry powder prepared above to an aqueous solution containing edible acetic acid at a solid-liquid ratio of 1:70 (m / v), stirring and mixing to form an extraction system, and extracting at 45-55° C. and pH 5.5-6.0 for 30-60 min, and obtaining a lotus leaf extract after the extraction;

[0050] S3, adding a cellulase and xylanase complex enzyme preparation to the lotus leaf extract obtained above in a ratio of 1:2, stirring and mixing, and then performing complex enzymolysis at 50° C. for 30 minutes. After the enzymolysis is completed, the entire system is an enzymolysis mixed liquid;

[0051] S4, ultrasonic extraction: transfer the enzymatic hydrolysis mixture into an ultrasonic device, and ultrasonically extract for 30 minutes at an ultrasonic frequency of 35-40 kHz, an ultrasonic power of 150-300 W, and an ultrasonic temperature of 40°C, and obtain an ultrasonic extraction mixture after the ultrasonic treatment is completed;

[0052] S5, filtering: filtering the ultrasonic extraction mixed solution obtained above, filtering and separating the precipitate to obtain the lotus leaf precipitate, and the filtrate obtained is the lotus leaf extract;

[0053] S6, soaking the residue: adding the lotus leaf precipitate obtained in step S5 into a small amount of clean water for soaking, the ratio is 1:1 (m / v), and after soaking for 50 minutes, filtering the precipitate to obtain lotus leaf residue precipitate and lotus leaf residue soaking liquid respectively;

[0054] S7, concentration and drying: the lotus leaf extract obtained in step S5 and the lotus leaf residue obtained in step S6 are combined and mixed, and then concentrated and freeze-dried to obtain a dry product, i.e., the lotus leaf extract.

[0055] In order to further illustrate the advantages of the technical solution of the present application and the difference between the currently disclosed technology, the following comparative examples are provided:

[0056] Comparative Example:

[0057] A water extraction preparation method of lotus leaf extract comprises the following steps:

[0058] S1. Select dry lotus leaves without impurities, mildew or deterioration, crush them with a grinder, and pass them through a 10-40 mesh sieve to obtain lotus leaf dry powder;

[0059] S2, adding the lotus leaf dry powder prepared above to an aqueous solution containing citric acid at a solid-liquid ratio of 1:70 (m / v), stirring and mixing to form an extraction system, and extracting at 45-55° C. and pH 5.0-6.0 for 30-60 min, and obtaining a lotus leaf extract after the extraction;

[0060] S3, adding a cellulase and xylanase complex enzyme preparation to the lotus leaf extract obtained above in a ratio of 2:1, stirring and mixing, and then performing complex enzymolysis at 50° C. for 30 minutes. After the enzymolysis is completed, the entire system is an enzymolysis mixed liquid;

[0061] S4, adding 5% edible acetic acid (v / v) to the enzymatic hydrolysis mixture, mixing evenly, and performing acid solution leaching to obtain an acid solution leaching solution;

[0062] S5, filtering the acidic solution extract obtained above, filtering and separating the precipitate to obtain the lotus leaf pulp precipitate, and the filtrate obtained is the lotus leaf extract;

[0063] S6, adding the lotus leaf precipitate obtained in step S5 into a small amount of clean water for soaking at a ratio of 1:1 (m / v), and filtering the precipitate after soaking for 50 minutes to obtain lotus leaf residue precipitate and lotus leaf residue liquid respectively;

[0064] S7, concentration and drying: the lotus leaf extract obtained in step S5 and the lotus leaf residue liquid obtained in step S6 are combined and mixed, and then concentrated and freeze-dried to obtain a dry product, i.e., the lotus leaf extract.

[0065] Comparison patent:

[0066] A method for efficiently and synchronously extracting flavonoids, alkaloids and polyphenols from lotus leaves using a water-based method: Patent number: CN202210103706.5.

[0067] S1, dried lotus leaves are crushed and passed through a 60-mesh sieve for later use;

[0068] S2, soaking the crushed lotus leaf powder in 50°C water for 30 min, adjusting the pH value with citric acid, adding cellulase and / or pectinase, and performing enzymolysis at 50°C for 2 h;

[0069] S3, after enzymatic hydrolysis, an aqueous solution of glycerol is added, and ultrasonic extraction is performed at a suitable temperature and time;

[0070] S4. After ultrasonic extraction, the extract was filtered and concentrated using a rotary evaporator.

[0071] The methods for determining the contents of the relevant components in the present invention are as follows: the content of nuciferine is determined by high performance liquid chromatography, the content of total flavonoids is determined by aluminum chloride-sodium nitrite colorimetry, and the content of total phenols is determined by Folin-Ciocalteu colorimetry. The contents of the effective components of the lotus leaf extracts in Example 1, Example 2, Example 3, Comparative Examples and Comparative Patents are determined and compared, as shown in Table 1 below.

[0072] Table 1 Determination of the content of active ingredients in lotus leaf extract

[0073]

[0074] Note: Total flavonoids are calculated as rutin, and total phenols are calculated as gallic acid.

[0075] The contents of nuciferine, total flavonoids and total phenols in the lotus leaf extract of the present invention are 71.37-83.80 mg / g, 70.35-92.58 mg / g (in terms of rutin) and 22.80-31.85 mg / g (in terms of gallic acid), respectively. Compared with the contents of the effective components of the lotus leaf extract of the present invention, the contents of nuciferine, total flavonoids and total phenols in the lotus leaf extract of the comparative example are lower than those in the embodiment, and the content of nuciferine in the lotus leaf extract of the comparative patent is lower, and the contents of total flavonoids and total phenols are higher;

[0076] Compared with water, the glycerol system (comparative patent) has better advantages in the extraction process of total phenols and total flavonoids, but the extraction rate of nuciferine in the glycerol system is low. In addition, although there is no limit requirement for the use of glycerol as a food additive / processing aid in GB2760, the lotus leaf extract of the comparative patent is ultimately a concentrated solution containing glycerol, while the present invention is a freeze-dried powder. Compared with the comparative patent, the present invention has more advantages in the convenience and acceptability of the application of lotus leaf extract, and the extraction agent of the present invention is water, which is lower in cost.

[0077] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing lotus leaf extract by water extraction, characterized in that: The specific steps are as follows: S1. Grinding and sieving lotus leaves: Select dry lotus leaves without impurities, mildew or deterioration, use a grinder to grind them, and pass them through a 0-40 mesh sieve to obtain lotus leaf dry powder; S2, weak acid extraction of dry powder: adding the lotus leaf dry powder prepared in step S1 to a weak acid aqueous solution, stirring and mixing to form an extraction system for extraction, and obtaining a lotus leaf extract after the extraction is completed; S3, enzymatic hydrolysis treatment: adding the composite enzyme preparation to the lotus leaf extract obtained in step S2, stirring and mixing, and then performing composite enzymatic hydrolysis. After the enzymatic hydrolysis is completed, the whole system is an enzymatic hydrolysis mixed liquid; S4, ultrasonic extraction: transferring the enzymatic hydrolysis mixture into an ultrasonic device for ultrasonic extraction, and obtaining an ultrasonic extraction mixture after the ultrasonic extraction is completed; S5, filtration treatment of the mixed solution: filtering the ultrasonic extraction mixed solution obtained in step S4, filtering and separating the precipitate to obtain the lotus leaf pulp precipitate, and obtaining the filtrate to obtain the lotus leaf extract; S6, soaking the residue: adding the lotus leaf precipitate obtained in step S5 into a small amount of clean water for soaking, filtering the precipitate after soaking, and obtaining lotus leaf residue precipitate and lotus leaf residue soaking liquid respectively; S7, concentration and drying: the lotus leaf extract obtained in step S5 is combined with the lotus leaf residue obtained in step S6, and mixed evenly, and concentrated and freeze-dried to obtain a dry product, i.e., the lotus leaf extract.

2. The water extraction preparation method of lotus leaf extract according to claim 1, characterized in that: In the step S2, the weak acid is one or both of edible acetic acid and citric acid.

3. The water extraction preparation method of lotus leaf extract according to claim 1, characterized in that: In step S2, the solid-liquid ratio of lotus leaf dry powder to weak acid aqueous solution is 1:70-1:100 (m / v), the amount of weak acid added is to adjust the pH of the extraction system to 5.0-6.0 using weak acid, the extraction temperature is 45-55° C., and the extraction time is 30-60 min.

4. The water extraction preparation method of lotus leaf extract according to claim 1, characterized in that: In the step S3, the composite enzyme preparation is cellulase (100,000 U / g) and xylanase (290,000 U / g), the enzymolysis temperature is 45-55°C, and the enzymolysis time is 30-70 min.

5. The water extraction preparation method of lotus leaf extract according to claim 1 or 4, characterized in that: The addition ratio of cellulase and xylanase in the composite enzyme preparation is 1:0.5-1:2, and the total addition amount of the two is 0.2-0.3%.

6. The water extraction preparation method of lotus leaf extract according to claim 1, characterized in that: The ultrasonic conditions in step S4 are as follows: ultrasonic frequency 30-40 kHz, ultrasonic power 150-300 W, ultrasonic time 30-50 min, and temperature 40-70°C.

7. The water extraction preparation method of lotus leaf extract according to claim 1, characterized in that: In step S6, the ratio of lotus leaf pulp precipitate to clean water in the soaking residue is 1:1-1:2 (m / v), and the soaking time is 30-60 min.

8. The water extraction preparation method of lotus leaf extract according to claim 1, characterized in that: In step S7, the content of nuciferine in the lotus leaf extract is 71.37-83.80 mg / g, the content of total flavonoids is 70.35-92.58 mg / g, and the content of total phenols is 22.80-31.85 mg / g.

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