Treatment method for enriching purple radish bud seedling anthocyanin

Abstract

The invention discloses a treatment method for enriching purple radish bud seedling anthocyanin, and belongs to the technical field of agricultural product processing. According to the method, purple radish seeds which are full and uniform in size serve as raw materials, the purple radish seeds are soaked in an ultrasonic-assisted sucrose aqueous solution or a sodium chloride aqueous solution, after germination accelerating and broadcast sowing are conducted, a nutrient solution is sprayed during cultivation, cultivation is conducted for 9 days, and the purple radish sprouting vegetable rich in anthocyanin can be obtained. Particularly, the contents of cyanidin chloride, delphinidin and peonidin-3-O-arabinoside can be obviously improved. The method is easy to operate, the anthocyanin content and nutritional quality of the purple radish sprouting vegetable can be effectively improved, a new method is provided for production of the sprouting vegetable rich in anthocyanin, meanwhile, new resources are provided for development of anthocyanin, and the application range of the purple radish sprouting vegetable in health food, leisure food and the like is widened.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural product processing, and particularly relates to a processing method for enriching anthocyanins in purple radish sprouts. Background Art

[0002] In recent years, influenced by factors such as changes in land resources, lifestyles, and healthy eating habits, sprout vegetables have garnered widespread attention from scholars across various fields due to their green, safe, nutritious, and disease-preventing properties. Currently, the most commercially valuable sprout vegetables come from families such as Leguminosae, Cruciferae, and Chenopodiaceae. Radish, a representative of the Cruciferae family, can be grown year-round and is a favorite among consumers. Radish sprouts also contain a high concentration of antioxidants, such as phenols and glucosinolates, and possess a higher nutritional value than mature radishes.

[0003] Soilless cultivation methods using nutrient-rich solutions have long been studied and proven beneficial for plant growth in modern commercial settings. Hydroponic systems rely on nutrients dissolved in water, which is the fundamental reason for nutrient accumulation at harvest. Currently, researchers both domestically and internationally are using nutrient solutions to cultivate high-nutrition sprouts. Exogenous additions have been well-documented to offer unique advantages in enhancing nutrition, improving sensory properties, and regulating health, demonstrating the broad potential of nutrient solution addition in the large-scale cultivation of high-value sprouts. Studies have shown that treatment with 2%-3% sucrose significantly increases the content of phytochemicals such as polyphenols, flavonoids, gamma-aminobutyric acid, and vitamins in sprouts, thereby enhancing their potential health benefits. Moderate salt treatment can induce a stress response in plants and promote the accumulation of secondary metabolites. Existing technologies use a 25 mmol / L salt solution to avoid excessive inhibition of sprouts while increasing the content of proline and antioxidants. In addition to the more widespread sugar and salt treatments, ultrasonic treatment, as a non-thermal physical stress method, can increase seed germination rate by stimulating plant cells through cavitation. Some studies have applied it to promote plant germination and metabolism and further optimize the quality of sprouts.

[0004] Research on radish sprouts has primarily focused on the growth regulation and nutritional enhancement of common varieties, such as red, white, and green radishes. Compared to common radish sprouts, research on purple radish sprouts is relatively scarce, especially regarding the regulation of anthocyanins, its key functional component. Research on anthocyanin enrichment has primarily focused on mature crops such as purple cabbage, purple sweet potato, and perilla. As a potential high-anthocyanin source, purple radish sprouts lack systematic research on exogenous regulation, and methods for enriching anthocyanins in radish sprouts have yet to be reported.

[0005] Based on this, this patent was invented, which uses ultrasound to coordinate exogenous nutrient solution treatment. By optimizing the treatment method, the growth and metabolic process of purple radish sprouts is regulated, the anthocyanin content and nutritional quality are significantly improved, and ultimately an organic and anthocyanin-rich high-quality radish sprout is obtained. Summary of the Invention

[0006] The present invention aims to provide a processing method for enriching anthocyanins in purple radish sprouts, and to improve the nutritional quality of the purple radish sprouts.

[0007] To achieve the above-mentioned object of the invention, the present invention adopts the following technical solution: a treatment method for enriching anthocyanins in purple radish sprouts, which is carried out according to the following steps:

[0008] (1) Raw material screening: Select purple radish seeds with uniform size, uniform seed coat color and full grains as raw materials.

[0009] (2) Ultrasonic-assisted sugar or salt soaking: The seeds screened in step (1) are placed in a soaking bag, and the soaking bag is placed in 5 times the volume of a 3% mass concentration sucrose aqueous solution or a 25 mmol / L sodium chloride aqueous solution. During the soaking, the ultrasonic power is controlled at 160 W, the frequency is 40 kHz, the ultrasound is carried out for 15 minutes, the soaking temperature is about 25°C, and the cumulative soaking time is 1 hour.

[0010] (3) Germination: Take out the seeds from step (3), wash them with clean water for 3 times, drain them, germinate them in the dark for 10 hours, and control the ambient temperature to about 25°C.

[0011] (4) Sowing and cultivation: Sow the seeds that have been germinated in step (3) on a germination tray covered with seedling paper, with a single layer covering 90% of the seedlings. During this period, spray 3% mass concentration sucrose solution or 25mmol / L sodium chloride solution every 12 hours to keep the seeds moist. After 48 hours, start light cultivation. In the late stage of seedling growth, spray 3% mass concentration sucrose solution or 25mmol / L sodium chloride solution.

[0012] The amount of mmol / L sodium chloride solution was increased to 1 times, the light period was 12h / d, the ambient temperature was about 25℃, and the culture was completed after 9 days, and anthocyanin-rich purple radish sprouts were obtained by ultrasound synergistically treating with sugar or salt.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] (1) The present invention provides a cultivation method for enriching anthocyanins and improving the nutritional quality of purple radish sprouts in the process of soilless culture sprout cultivation. By using exogenous nutrient solution and ultrasound-assisted soaking technology, purple radish sprouts with high anthocyanin content are obtained through seed soaking, germination, and germination cultivation. Not only is the appearance quality greatly improved, but also nutritious purple radish sprouts are obtained.

[0015] (2) In the food industry, purple radish sprouts with high anthocyanin content can be used as natural colorants, providing new resources for the development of anthocyanin products and broadening their application in functional beverages, nutritionally fortified baked goods, and high-end snack foods. In addition, their application scope is also more extensive in the development of health foods, cosmetic raw materials, and agricultural industrialization.

[0016] (3) The present invention does not use any pesticides or fertilizers, is simple to operate, economically feasible, safe and pollution-free, and can be easily applied to the production and processing of functional sprouts. DETAILED DESCRIPTION

[0017] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below.

[0018] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0019] The technical solution of the present invention is further described below with reference to specific implementation cases. The protein content of the radish sprouts of the present invention is determined by the biuret reagent method. The total sugar content is determined by the NT / T 2332-2013 method, i.e., the DNS spectrophotometric method. The polyphenol determination method uses the Folin-phenol method. Flavonoids are determined by reference to the method of Zhao Dengqi et al. (Zhao Dengqi, Sun Yatian, Huang Jianying et al. Determination of bioactive components in broccoli leaves), and anthocyanins are determined by DB 22 / T 2529-2016. Phytic acid is determined in accordance with GB5009.153-2016. Glucosinolates are determined by the method of Ma Licong (Ma Licong. Research on optimization of extraction process of glucosinolates from Chinese cabbage [D]. Guangzhou University, 2024. DOI: 10.27040 / d.cnki.ggzdu.2024.001715). Anthocyanin monomers are determined by high performance liquid chromatography with reference to Jan et al.'s method (RT Journal Article A1 Jan A1 Antoniadi,Ioanna A1 et al. Plant Hormonomics: Multiple Phytohormone Profiling by Targeted Metabolomics, Plant Physiology, Volume 177, Issue 2, June 2018, Pages 476-489, https: / / doi.org / 10.1104 / pp.18.00293).

[0020] Example 1

[0021] The invention discloses a method for preparing purple radish seeds with uniform size, uniform seed coat color and full grains, after washing them three times with oxygen-enriched water, putting them into a seed soaking bag, and placing them into a 5-fold volume of a 3% mass concentration sucrose solution, the soaking temperature is about 25°C, the ultrasonic power is controlled at 160W, the frequency is controlled at 40kHz, the ultrasonic treatment time is 15min, and the cumulative soaking time is 1h; the seed soaking bag is taken out, the seeds are washed three times with clean water, drained, and germinated in the dark for 10h; the germinated seeds are sown in a germination tray covered with seedling paper, with a single layer covering 90% of the whole, and a 3% mass concentration sucrose solution is sprayed every 12h to moisten the seeds, and the ambient temperature is about 25°C; after 48h, light culture is started, and the amount of the 3% mass concentration sucrose solution sprayed is increased to 1 times in the late growth stage of the sprouts, the photoperiod is 12h / d, the ambient temperature is about 25°C, and the culture is carried out for 9 days to obtain anthocyanin-rich purple radish sprouts treated with ultrasound and sugar.

[0022] Example 2

[0023] The steps are the same as those in Example 1, except that the seed soaking solution is a 25 mmol / L sodium chloride solution and the 25 mmol / L sodium chloride solution is sprayed during the sprout growth period to obtain anthocyanin-rich purple radish sprouts treated with ultrasound and salt.

[0024] Comparative Example 1

[0025] The steps are the same as those in Example 1, except that the seed soaking solution and the spraying solution during the sprout growth period are both tap water, and no ultrasonic treatment is applied.

[0026] Comparative Example 2

[0027] The steps are the same as those in Example 1, except that the seed soaking solution and the spraying solution during the seedling growth period are both tap water, and ultrasonic treatment is applied, and the ultrasonic conditions are 40 kHz, 160 W, and 15 min.

[0028] Comparative Example 3

[0029] The steps are the same as those in Example 1, except that the seed soaking solution and the spraying solution during the sprout growth period are both sucrose solutions with a mass concentration of 3%, and no ultrasonic treatment is applied.

[0030] Comparative Example 4

[0031] The steps are the same as those in Example 1, except that the seed soaking solution and the spraying solution during the seedling growth period are both 25 mmol / L sodium chloride solutions, and no ultrasonic treatment is applied.

[0032] Table 1 shows the effects of ultrasound combined with sugar or salt treatment on the germination and growth morphology of purple radish. As can be seen from the table, at the early 12-hour mark, Example Groups 1 and 2 outperformed the Comparative Example Group. Early ultrasound combined with low-concentration sugar or salt significantly promoted germination through osmotic regulation and energy supply in the short term. At 24 hours of germination, osmotic stress intensified, and germination slowed in Comparative Examples 3 and 4. However, ultrasound combined with sucrose treatment alleviated damage by improving membrane permeability. The germination rate of the Example 1 ultrasound-combined sucrose group (14.75%) was significantly higher than that of the Example 3 sucrose group (6.50%); and the Example 2 ultrasound-combined sodium chloride group (28.75%) was significantly higher than that of the Example 4 sodium chloride group (17.50%). At 24 hours, Example 2 had the highest germination rate, germination index, plant height, and fresh and dry weight of the 9-day-old seedlings, indicating that seed vigor was high and the germination state was optimal at this time.

[0033] Table 1 Germination rate and growth morphology changes of purple radish sprouts under ultrasound synergistic sugar or salt treatment

[0034]

[0035] Note: Different letters in the same column represent significant differences (p<0.05).

[0036] Table 2 is an analysis of the effects of ultrasound on the bioactive component content of purple radish sprouts in combination with sugar or salt treatment. As can be seen from the table, Example 2 exhibits significant metabolic advantages during the growth of purple radish sprouts. The polyphenol content in Example 2 may be lower than that in Comparative Example 1 due to the redistribution of its carbon source. The total flavonoid content in Example 2 is significantly higher than that in Comparative Example 1 by about 4 mg / g, reaching 24.82 mg / g. Phytic acid is continuously consumed during plant growth and its content decreases. Compared with the other groups, Example 2 has the smallest decrease, only 1.4 mg / g. Compared with a single stress treatment, ultrasound-assisted salt solution combined treatment can alleviate the stress effect and significantly improve the synthesis efficiency of antioxidants. The glucosinolate content and total flavonoid content of Example 2 both reached their maximum values, which were 264.2 μmol / g and 24.82 mg / g, respectively, while the total sugar content was the lowest at 11.53%, which was significantly lower than that of the Comparative Example group and Example 1. The above results show that ultrasound-assisted sodium chloride treatment significantly outperformed other groups in the accumulation of nutrients and functional components, especially anthocyanins and flavonoids. The anthocyanin content was 10.55 mg / g, a 5% increase compared to Comparative Example 1. The nutritional value of purple radish sprouts was improved overall, and their low sugar content and high glucosinolate content further demonstrated their superior blood sugar-lowering potential and anti-cancer activity.

[0037] As can be seen from Table 3, the anthocyanin content in Example 2 and Comparative Example 4 is significantly higher than that in Comparative Example 1, which confirms that both ultrasonic synergistic salt treatment and single salt treatment can effectively promote anthocyanin biosynthesis. Therefore, the differences in its components are further explored. The content of anthocyanin monomers shows differential effects due to the specificity of each monomer metabolic pathway and the specificity of gene regulation expression. After ultrasonic synergistic sodium chloride treatment in Example 2, the anthocyanin monomers delphinidin and cyanidin chloride were significantly higher than those in Comparative Examples 1 and 4 (p < 0.05).

[0038] Table 2 Analysis of the content of bioactive components in purple radish sprouts after ultrasound synergistic sugar or salt treatment

[0039]

[0040] Note: Different letters in the same column represent significant differences (p<0.05).

[0041] Table 3 Analysis of anthocyanin monomer content in purple radish sprouts treated with NaCl and ultrasound synergistic with NaCl (ng / g)

[0042]

[0043] Note: Different letters in the same column represent significant differences (p<0.05).

[0044] While the present invention has been described in terms of what are presently considered to be the most preferred and practical embodiments, it should be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and equivalent arrangements within the spirit and scope of the appended claims, which scope is to be given the broadest interpretation so as to encompass all such modifications and equivalent structures permitted under the law.

Claims

1. A method for enriching anthocyanins in purple radish sprouts, characterized in that Follow these steps: (1) Raw material pretreatment: Select purple radish seeds with uniform size, uniform seed coat color, and full grains as raw materials; wash them three times with tap water; (2) Ultrasonic-assisted sugar or salt soaking: the seeds screened in step (1) are placed in a soaking bag and placed in a certain volume of nutrient solution for soaking, wherein the seeds are soaked with ultrasound assistance at a certain temperature for a certain cumulative soaking time; (3) Germination: Take out the seeds soaked in step (2), wash them with clean water three times, drain them, germinate them in the dark, and control the ambient temperature to about 25°C; (4) Sowing and cultivation: The seeds germinated in step (3) are sown in a germination tray covered with seedling paper, and light cultivation is started after 48 hours. The ambient temperature is controlled at 25° C. and the cultivation is completed after 9 days to obtain purple radish sprouts treated with ultrasound-assisted nutrient solution.

2. The method for enriching anthocyanins in purple radish sprouts according to claim 1, characterized in that The seed soaking nutrient solution in step (2) is a sucrose solution with a mass concentration of 3% or a 25mmol / L sodium chloride solution, and the volume of the nutrient solution is 5 times the volume of the purple radish seeds. The seed soaking temperature is about 25°C and the seed soaking time is a cumulative 1h.

3. The method for enriching anthocyanins in purple radish sprouts according to claim 1, characterized in that The conditions for ultrasonic-assisted seed soaking in step (2) are: ultrasonic power 160 W, frequency 40 kHz, and ultrasonic time 15 min.

4. The method for enriching anthocyanins in purple radish sprouts according to claim 1, wherein The dark-proof germination time in step (3) is 10 hours.

5. The method for enriching anthocyanins in purple radish sprouts according to claim 1, characterized in that Step (4) The seeds after germination are transferred to a sowing seedling tray, and the single layer is 90% filled. During this period, 3% sucrose solution or 25 mmol / L sodium chloride solution is dispersedly sprayed every 12 hours to keep the seeds moist.

6. The method for enriching anthocyanins in purple radish sprouts according to claim 1, characterized in that In step (4), light culture is started after 48 hours, during which the photoperiod is 12 hours / day. In the late growth stage of the seedlings, 3% mass concentration sucrose solution or 25 mmol / L sodium chloride solution is sprayed in an amount doubled.

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