Low-energy-consumption ginseng leaf drying method capable of effectively retaining active ingredients

Abstract

The invention discloses a low-energy-consumption ginseng leaf drying method capable of effectively retaining active ingredients, and relates to the technical field of ginseng leaf processing, and the ginseng leaf drying method comprises the steps of pretreatment, airing, hot air drying and crushing. According to the method, low-temperature hot air drying is adopted, drying to constant weight is taken as an index, the preservation time is prolonged, further exploration of active ingredients of the ginseng leaves is facilitated, and the energy consumption is far lower than that of a freeze drying process with the same index. The verification process of two varieties of ginseng leaves, namely, the Feikingsi and the Feikingsi No.1, shows that the drying process retains a large amount of active substances, has no significant difference in antioxidant activity compared with a shade-drying and freeze-drying process, can be independently brewed for eating, can also be matched with traditional Chinese medicine food materials for use to develop foods, health foods, medicines and the like, and has a wide application prospect. The ginseng leaves are further developed and utilized, and the ginseng leaves have wide application prospects and market space.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural product processing and relates to a process for drying ginseng leaves. Background Art

[0002] Ginseng leaves are sweet and bitter in nature, cold in taste, and have the effects of replenishing qi, benefiting the lungs, removing heat, and promoting the production of body fluids. Modern studies have shown that ginseng leaves and ginseng have similar chemical compositions, both containing ginsenosides, polysaccharides, and flavonoids (Ji Ruifeng, Yuan Yuan, Liu Juan. Analysis of the differences in the chemical and pharmacological activities of ginseng leaves and ginseng [J]. Chinese Journal of Traditional Chinese Medicine, 2017, 32(05): 2269-2272.). Among them, ginseng polysaccharides have multiple pharmacological activities such as immunomodulation, anti-tumor, and antioxidant (Sun Mengxiao, Chen Ruizhan, Luo Shujun, et al. Study on microwave-assisted extraction and antioxidant activity of ginseng leaf polysaccharides [J]. Journal of Changchun Normal University, 2021, 40(02): 105-112.). Ginseng and ginseng leaves are both included in the Pharmacopoeia of the People's Republic of China. The latter is the dried leaves of the plant (Ji Ruifeng, Yuan Yuan, Liu Juan. Analysis of the differences in chemical and pharmacological activities between ginseng leaves and ginseng [J]. Chinese Journal of Traditional Chinese Medicine, 2017, 32(05): 2269-2272.), which are harvested in autumn and usually air-dried or oven-dried.

[0003] Drying is one of the key links in the processing of Chinese medicinal materials and decoction pieces. There are differences in drying methods and drying temperatures between different medicinal parts. Leaf, whole herb and flower Chinese medicinal materials are not suitable for high temperature drying. (Xuan Feiyang, Jiang Dan, Zhang Jiawen, et al. Current status and development trend of fresh processing of Chinese medicinal materials [J]. Modern Chinese Medicine, 2022, 24(10): 1840-1849.) As early as in the "Shennong Herbal Classic", there were records of drying such as "shade drying and sun drying". Modern drying methods for Chinese medicinal materials mainly include air drying, freeze drying, microwave drying, etc. (Ren Difeng, Mao Zhihuai. Current status and development trend of Chinese herbal medicine drying in my country [J]. Transactions of the Chinese Society of Agricultural Engineering, 2001, (02): 5-8.) Among them, shade drying, low-temperature hot air drying and freeze drying can more effectively preserve the activity of ginseng leaves. Traditional natural drying methods are inefficient, and the quality of medicinal material drying varies greatly, which seriously restricts the development of the Chinese medicine industry. (Wang Leyi, Li Changhe, Liu Mingzheng, et al. Research status of Chinese herbal medicine drying technology and equipment [J]. Transactions of the Chinese Society of Agricultural Engineering, 2024, 40(02): 1-28.) Modern freeze-drying technology has the disadvantages of high equipment cost, high energy consumption, and long production cycle, which creates economic and time burdens for enterprises in practical applications. At present, no literature has reported a more practical preparation method for drying ginseng leaves.

[0004] Therefore, the present invention proposes a method for preparing dried ginseng leaves with low energy consumption and effective retention of active ingredients. The present invention aims to provide an effective processing technology for drying ginseng leaves, which is short in time, low in energy consumption, and good in activity, and is convenient for further infrared spectroscopy analysis, structural exploration of the effective ingredients of ginseng leaves, and selection of a suitable extraction method for deep processing of ginseng leaves. It can be brewed and eaten alone, and can also be used in combination with Chinese medicinal ingredients to develop food, health food, medicine, etc., with broad application prospects and market space. Summary of the invention

[0005] The purpose of the present invention is to provide a ginseng leaf drying process, which can take into account both process energy consumption and product appearance while retaining a large amount of ginseng leaf active ingredients, and effectively solve the problem that the appearance of ginseng dried leaves is uneven and energy consumption and quality cannot be taken into account.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] 1. A method for drying ginseng leaves with low energy consumption and effective retention of active ingredients, comprising the following steps:

[0008] (1) Pretreatment of ginseng leaves: selecting fresh ginseng leaves that have been yellowed, diseased, moldy, or rotten, removing the stems, soaking in water, and rubbing with hands to remove dirt and spider webs on the leaf surface;

[0009] (2) Dry, lay the leaves flat to prevent them from rotting, and place them in a cool and ventilated place to dry for 80-90 minutes until there is no moisture on the leaf surface;

[0010] (3) Drying: Spread the ginseng leaves evenly on a tray to prevent uneven and incomplete drying. Use a 45°C hot air drying device to dry for 6.5-7 hours until constant weight is reached. Use an electric power monitor to monitor the unit energy consumption, which is 6.897×10 -3 -7.529×10 -3 kwh / g;

[0011] (4) Grinding: Grinding the dried ginseng leaves into irregular pieces with a diameter not exceeding 5 mm.

[0012] 2. The present invention uses 45°C low-temperature hot air drying for 6.5-7h.

[0013] 3. The present invention uses the constant weight of ginseng leaves as the drying completion index, prolongs the storage time, and facilitates the exploration of the active ingredient structure of ginseng leaves by infrared spectrometers and other measuring instruments.

[0014] 4. The total energy consumption of the present invention is 0.555-0.598 kwh, which is much lower than the total energy consumption of the freeze-drying process with the same index of 21.574-21.870 kwh.

[0015] 5. Crush the dried ginseng leaves into irregular pieces with a diameter not exceeding 5 mm for easy storage and processing into products.

[0016] 6. The evaluation index of the Ganoderma lucidum cutting process of the present invention is: total score = (appearance evaluation score × 0.5) + (energy consumption × 0.3) + (time consumption × 0.2), and the low-temperature hot air drying has the highest comprehensive score.

[0017] 7. The present invention is based on the premise of retaining the active substances and pharmacological activity of ginseng leaves to the greatest extent, and compares the advantages and disadvantages of the three processes of shade drying, low-temperature hot air drying, and freeze drying.

[0018] 8. The present invention simultaneously uses three drying methods to treat the ginseng leaves, and detects the saponin, polysaccharide content and antioxidant activity. Under low-temperature hot air drying, the saponin content of Fuxingyan ginseng leaves is 14.95% ± 1.31, the polysaccharide content is 21.45% ± 1.51, and the ABTS system IC 50 The value is 6.46mg / ml±0.58. The saponin content of Fuxingyan No. 1 is 16.20%±1.27, the polysaccharide content is 23.85%±1.97, and the ABTS system IC 50 The value was 6.93 mg / ml±0.60. There was no significant difference in saponin content, polysaccharide content and antioxidant activity compared with traditional shade drying and freeze drying (p>0.05).

[0019] Beneficial effects of the present invention:

[0020] Applying for a patent will be beneficial to the development and application of ginseng leaves. Fresh ginseng leaves are used through a series of steps including pretreatment, air-drying, drying and crushing. With appearance evaluation, energy consumption and time consumption as evaluation indicators, it is concluded that dried ginseng leaves have the following characteristics:

[0021] (1) Low-temperature hot air drying makes the leaves emerald green with a light leaf fragrance, without the yellowing caused by slow shade drying and without the black spots caused by freeze drying.

[0022] (2) The leaves are dried to a constant weight, feel crisp, and have slightly curled edges, which prolongs the shelf life and facilitates storage and processing.

[0023] (3) It is convenient to use infrared spectrometers and other measuring instruments to explore the structure of active ingredients in ginseng leaves.

[0024] (4) By monitoring the unit energy consumption and drying time, the total energy consumption of 45°C hot air drying is much lower than that of freeze drying, and the drying time is the shortest among the three processes, with the best overall practicality.

[0025] (5) The saponin and polysaccharide contents and antioxidant activity of the two varieties of samples were tested. There was no significant difference in saponin content, polysaccharide content and antioxidant activity between the two varieties of samples and those obtained by traditional shade drying and freeze drying (p>0.05).

[0026] (6) The powder is crushed into irregular pieces with a diameter of no more than 5 mm, which can be brewed and eaten alone, or used in combination with Chinese medicinal ingredients to develop food, health food, medicine, etc. After brewing alone, the solution is yellow with a light leaf fragrance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Comparison of saponin content in three drying methods of ginseng leaves; Figure 2 Comparison of polysaccharide contents in three drying methods of ginseng leaves; Figure 3 Comparison of in vitro antioxidant activities of three drying methods of ginseng leaves. DETAILED DESCRIPTION

[0028] Example 1: Comparison of three ginseng leaf drying processes

[0029] Wash the ginseng leaves harvested in October and lay them flat in a cool and ventilated place to dry for 80-90 minutes until there is no moisture on the leaf surface.

[0030] Appearance evaluation, energy consumption and time consumption were selected as indicators for comprehensive assessment, and the total score = (appearance evaluation score × 0.5) + (energy consumption × 0.3) + (time consumption × 0.2).

[0031] 1. Shade drying process: Take dry fresh ginseng leaves, place them in a cool place outdoors to dry after 7:30 in the morning, and store them indoors after 19:30 in the evening, for 12 hours a day, until the weight is constant, which takes 4 days.

[0032] 2. Low-temperature hot air drying process: Take the dried fresh ginseng leaves and dry them at 45°C until the mass is constant. It takes 6.5-7 hours. The unit energy consumption is 6.897×10 -3 -7.529×10 -3 kwh / g.

[0033] 3. Freeze-drying process: Take dry fresh ginseng leaves, pre-freeze at -20°C for 1 day, and freeze-dry at -30°C and 0.1Pa until the mass is constant. It takes 36.5-37 hours. The unit energy consumption is monitored by an electric power monitor and is 1.084-1.097 kwh / g.

[0034] The results showed that the shade-dried ginseng leaves were yellowish in color, had severe curling and uneven quality, and scored 6 points for appearance, 10 points for no energy consumption, and 4 points for 4 days. The hot-air-dried ginseng leaves were emerald green and slightly yellow in color, with curled edges and no significant difference in quality between different batches. The appearance scored 8 points, and the unit energy consumption was 6.897×10 -3 -7.529×10 -3kw h / g, scored 8 points, took 6.5-7h, scored 8 points; freeze-dried color is emerald green but has black spots caused by freezing, the leaf edges are curled, there is no obvious difference in quality between different batches, the appearance scored 8 points, unit energy consumption: 1.084-1.097kwh / g, scored 6 points, took 36.5-37h, scored 6 points.

[0035] Table 1 Weighted scores of ginseng leaves with three different drying processes

[0036]

[0037] It can be seen from Table 1 that hot air drying is the best in practical application.

[0038] Example 2: Ginseng leaf drying process

[0039] The process was verified using two varieties of ginseng leaves, Fuxingyan and Fuxingyan No. 1, harvested in October.

[0040] 1. Pretreatment of ginseng leaves: select fresh ginseng leaves that have been yellowed, diseased, moldy, or rotten, remove the stems, soak in water, and rub with your hands to remove dirt and spider webs on the leaf surface;

[0041] 2. Dry, lay the leaves flat to prevent them from rotting, and place them in a cool and ventilated place to dry for 80-90 minutes until there is no moisture on the leaf surface;

[0042] 3. Drying: Spread the ginseng leaves evenly on a tray and dry them in a 45°C hot air drying device for 6.5-7 hours until constant weight is reached. The unit energy consumption is 6.897×10 -3 -7.529×10 -3 kwh / g;

[0043] 4. Crush the dried ginseng leaves into irregular pieces with a diameter not exceeding 5 mm.

[0044] Example 3: Comparison of polysaccharide and saponin contents in three processes

[0045] 1. Determination of saponin content

[0046] The content of ginsenosides in ginseng leaves was determined by the vanillic acid-glacial acetic acid-perchloric acid method. An appropriate amount of ginsenoside Re reference substance was taken, accurately weighed, and methanol was added to make a solution containing 1 mg per 1 ml to obtain the reference substance solution. Accurately pipette 20μl, 40μl, 80μl, 120μl, 160μl, and 200μl of the reference substance solution into stoppered test tubes, respectively, evaporate the solvent at low temperature, add 0.2ml of 5% vanillin glacial acetic acid test solution and 0.8ml of perchloric acid, place in a 60°C constant temperature water bath to mix thoroughly, heat for 15 minutes, immediately cool with ice water for 2 minutes, add 5ml of glacial acetic acid, and shake well; use the reagent as a blank. After eliminating bubbles, use the UV-visible spectrophotometer to measure the absorbance at a wavelength of 550nm, and draw a standard curve y=2.1916x-0.0061 with absorbance as the ordinate and concentration as the abscissa. 2 =0.9986, and the linear range is 0.02-0.2mg with good linear relationship.

[0047] Sample preparation of ginsenosides from ginseng leaves: Ultrasonic-assisted extraction was used, with the solvent being 70% ethanol, at a power of 240 W, with a solid-liquid ratio of 1:35 g / ml, at a temperature of 60°C for 45 min, and then filtered and the filtrate was fixed to 25 ml.

[0048] 2. Determination of polysaccharide content

[0049] The polysaccharide content of ginseng leaves was determined by the phenol-sulfuric acid method. The standard curve was drawn with different concentrations of anhydrous glucose. The absorbance was measured at a wavelength of 490 nm using an ultraviolet spectrophotometer. The concentration of anhydrous glucose solution (mg / mL) was used as the abscissa and the absorbance value as the ordinate. The equation for the standard curve was y=6.2921x+0.1376, R 2 =0.9990, and the linear range is 0.02-0.01 mg / mL with good linear relationship.

[0050] Sample preparation of ginseng leaf polysaccharide: Soxhlet extraction was used, with pure water as the solvent, at 100°C, with a solid-liquid ratio of 1:100 g / mL for 4 h, and then filtered and the filtrate was fixed to 100 ml.

[0051] Table 2 Comparison of saponin and polysaccharide contents under different drying methods

[0052]

[0053] Note: Different lowercase letters in the same column indicate significant differences among treatments (P<0.05).

[0054] The saponin content of ginseng leaves dried by low-temperature hot air in Fuxingyan is 14.95%±1.31, and the polysaccharide content is 21.45%±1.51; the saponin content of Fuxingyan No. 1 dried by low-temperature hot air is 16.20%±1.27, and the polysaccharide content is 23.85%±1.97.

[0055] The saponin content and polysaccharide content of both tended to be lower than that of the freeze-drying process, but there was no significant difference (p>0.05).

[0056] Example 4: Comparison of in vitro antioxidant activity of three processes

[0057] 1. Preparation of ABTS solution

[0058] ABTS solution (5 ml, 7.0 mM) and K2S2O8 solution (88 μl, 140 mM) were mixed evenly and reacted in the dark for 12-16 h to generate ABTS. + Before use, ABTS + The cation was diluted with ultrapure water to an absorbance of 0.700±0.02 at 734 nm.

[0059] 2. ABTS free radical scavenging experiment of ginseng leaves processed by three methods

[0060] Add different concentrations of dilutions (20 μl) to a 96-well plate and then add ABTS + The cationic solution (180 μl) was reacted at room temperature in the dark for 6 minutes, and the absorbance was measured at 734 nm. The ABTS free radical scavenging rate was calculated according to the formula:

[0061]

[0062] Among them, A0, A1 and A2 are the absorbance values ​​of blank group, control group and sample group respectively. + The clearance rate was plotted as the vertical axis and the sample concentration as the horizontal axis, and the IC of ginseng leaves from the three processes was calculated. 50 value.

[0063] Table 3 Comparison of antioxidant activity under different drying methods

[0064]

[0065] Note: Different lowercase letters in the same column indicate significant differences among treatments (P<0.05).

[0066] Fuxingyan low temperature hot air drying ginseng leaf ABTS system IC 50 The value is 6.46mg / ml±0.58; Fuxingyan No. 1 low temperature hot air drying ginseng leaf ABTS system IC 50 The value was 6.93 mg / ml±0.60, and there was no significant difference in antioxidant activity (p>0.05).

[0067] In summary, the 45℃ low-temperature drying process has the best application value after comprehensive evaluation of its appearance, energy consumption, and duration; there is no significant difference in the main active ingredients of ginseng leaves, such as polysaccharides and saponins, compared with traditional shade drying. There is a trend lower than freeze drying in different samples, but there is no significant difference, and the active ingredients of ginseng leaves are still well preserved; there is no significant difference in the antioxidant activity of the low-temperature drying process compared with shade drying and freeze drying. Therefore, after comprehensive consideration of various factors, it is concluded that the low-temperature drying process is more practical.

[0068] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement modes and shall be included in the protection scope of the present invention.

Claims

1. A method for drying ginseng leaves with low energy consumption and effective retention of active ingredients, characterized in that: The preparation process includes the following: (1) Pretreatment of ginseng leaves: selecting the ginseng leaves, removing the stems, and washing with water; (2) Drying to remove moisture from the leaf surface; (3) Drying: Spread the ginseng leaves evenly on a tray and dry them using a hot air drying device at 45°C; (4) Grinding: Grinding the dried ginseng leaves into irregular pieces.

2. A method for drying ginseng leaves with low energy consumption and effective retention of active ingredients according to claim 1, characterized in that: (1) Select fresh ginseng leaves that have been yellowed, diseased, moldy, or rotten, soak them in water, and rub them with your hands to remove dirt and spider webs on the leaf surface.

3. A method for drying ginseng leaves with low energy consumption and effective retention of active ingredients according to claim 1, characterized in that: (2) Spread the leaves flat to prevent them from rotting, and place them in a cool and ventilated place to dry until there is no moisture on the leaf surface. The drying time is 80-90 minutes.

4. A method for drying ginseng leaves with low energy consumption and effective retention of active ingredients according to claim 1, characterized in that: (3) The hot air dryer is set to 45°C and the drying time is 6.5-7h.

5. The method for drying ginseng leaves with low energy consumption and effective retention of active ingredients according to claim 1, characterized in that: (3) The constant weight of ginseng leaves is used as the drying completion index.

6. The method for drying ginseng leaves with low energy consumption and effective retention of active ingredients according to claim 1, characterized in that: (3) The total energy consumption of the drying process is 0.555-0.598 kwh, and the unit energy consumption is 6.897×10 -3 -7.529×10 -3 kwh / g, which is much lower than the freeze-drying process with the same index.

7. A method for drying ginseng leaves with low energy consumption and effective retention of active ingredients according to claim 1, characterized in that: (4) The diameter of irregular fragments does not exceed 5 mm.

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