Preparation method and application of contact glow discharge plasma activated water for promoting callus of carrot taproot

Abstract

The invention relates to the technical field of preparation of plasma activated water, in particular to a preparation method and application of contact glow discharge plasma activated water for promoting callus of carrot Straight Root The preparation method comprises the following steps: putting 1L of a 1-2g / L calcium chloride solution into a glass container, inserting a platinum electrode as an anode and a carbon rod as a cathode, the distance between the positive electrode and the negative electrode is adjusted to be 10-15 cm, and the temperature of the solution is controlled by a circulating water bath; a power supply is switched on, the voltage of the power supply is adjusted from 0-700V, when the voltage exceeds a critical value, the anode generates stable glow discharge, the voltage is controlled to be 500-550V, and the voltage is kept for 10-20 minutes; and storing the prepared plasma activated water in a sealed manner, and drying in the shade for 6 hours for later use. According to the method, the damaged carrot taproot is treated through contact glow discharge plasma activated water, accumulation of polyphenol cork grease and lignin at the wound of the carrot taproot can be promoted, and formation of a sealing layer is accelerated; meanwhile, the nutritional quality of the carrot straight roots is improved, and high-energy active substances in the carrot straight roots are high in degradation speed.

Description

Technical Field

[0001] The invention relates to the technical field of plasma activated water preparation, in particular to a method for preparing contact glow discharge plasma activated water for promoting carrot taproot healing and application thereof. Background Art

[0002] Carrot is one of the top ten vegetable crops in the world. It is rich in active ingredients and nutrients such as carotene, dietary fiber, vitamins, soluble sugars and proteins. It has health benefits such as anti-aging, enhancing immunity and preventing cardiovascular diseases. my country's carrot planting area accounts for about 40% of the world's total area, and both planting area and total output rank first in the world. Since carrot taproots have a crisp and tender skin and are mostly harvested mechanically, mechanical damage is inevitable during the harvesting and post-harvest grading, packaging and other commercial processing. These wounds will accelerate water transpiration and physiological metabolism, causing carrots to lose water and wilt and a rapid decline in nutritional quality, seriously affecting the value of the product.

[0003] Although carrot taproots have the ability to heal themselves, they can deposit a large amount of suberin and lignin on the wound surface to form a callus sealing layer, enhance the ability to resist external damage, and inhibit water evaporation. However, natural healing takes a long time, and in actual production, the wound is often stored or circulated when it is not completely healed, resulting in serious quality loss and reduced commercial value. Although it has been reported that hot water treatment can accelerate the accumulation of polyphenol suberin and lignin in carrot wounds and promote healing (Food Science, 2022, 43, (07), page 182), the equipment cost involved in the treatment is high and the treatment efficiency is low. At the same time, high temperature will accelerate the maturation, aging and quality deterioration of carrot taproots. Therefore, it is particularly important to develop low-temperature healing technology to promote wound healing without affecting the appearance and nutritional quality of carrots, which is particularly important for improving carrot quality and the sustainable development of the industry.

[0004] Contact glow discharge plasma is a type of low-temperature plasma. Its principle is that under the action of DC high voltage, the metal anode in the water containing electrolyte will produce a stable glow discharge, causing water molecules to dissociate into ·OH, ·H and H 2 O 2 The various highly oxidizing active substances are called plasma because the overall positive and negative charges of these substances are equal. The aqueous solution is contact glow discharge plasma activated water. When NaCl is used as the electrolyte, the active particles generated can make Cl - Oxidation to generate Cl 2 and ClO - , while ClO -It has strong oxidizing properties, thus enhancing the oxidizing capacity of the plasma system. In recent years, glow discharge plasma has been mainly used in research on food sterilization, toxin degradation and preservation. Since the active substances in glow discharge plasma have strong oxidizing properties and fast degradation rate, they avoid negative impacts on the environment and human health. At the same time, they have the characteristics of low processing temperature, high efficiency and no residue. Therefore, it has broad application prospects. At present, there is no research on the application of contact glow discharge plasma activated water to promote carrot wound healing. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a preparation method and application of contact glow discharge plasma activated water for promoting carrot taproot healing.

[0006] In order to achieve the above purpose, the technical solutions provided are as follows:

[0007] A method for preparing contact glow discharge plasma activated water for promoting carrot taproot healing, characterized in that it comprises the following steps:

[0008] Step 1: Place 1L of 1-2g / L calcium chloride solution in a glass container, insert a platinum electrode (a platinum wire with a diameter of 0.5-1.0mm sealed in a sintered quartz tube with the tip exposed) as an anode, and a carbon rod (with a diameter of 5-10mm) as a cathode. Adjust the distance between the positive electrode and the negative electrode to 10-15cm, and control the solution temperature by a circulating water bath;

[0009] Step 2: Turn on the power supply and adjust the power supply voltage from 0-700V. When the voltage exceeds the critical value, the anode produces a stable glow discharge. Control the voltage at 500-550V and maintain it for 10-20 minutes.

[0010] Step 3: Seal and store the prepared plasma activated water in a cool and dry place for use within 6 hours.

[0011] Artificial simulated injury and soaking treatment of carrot taproot: After washing the carrots with tap water, soak them in 1% sodium hypochlorite solution for 2 minutes for disinfection, rinse them with distilled water, dry them, and use a 75% alcohol-sterilized scraper to cut three wounds of 50mm×15mm×1mm (length×width×depth) at 30mm from the top and bottom of each taproot. The carrots were randomly divided into two groups; one group was soaked in contact glow discharge plasma activated water for 10 minutes, and the other group was soaked in distilled water for 10 minutes as a control. After drying, the carrots were put into perforated fresh-keeping bags, and the wound healing effect was evaluated and the nutritional quality was determined after 5 days of healing in a dark room temperature environment.

[0012] Determination of callus effect and nutritional quality indicators of carrot taproot: Suberinpolyphenolic (SPP) and lignin deposition are typical characteristics of callus sealing layer formation in fruits and vegetables. In this experiment, the autofluorescence of SPP in the wound site of carrot taproot was observed by fluorescence microscopy, and the deposition of lignin in the wound site of carrot taproot was observed by phloroglucinol and concentrated hydrochloric acid staining; the weight loss rate of carrot taproot after callus was determined by weighing method, the hardness of callus tissue was determined by TA-300W texture analyzer, the chroma of carrot was measured by CM-700d colorimeter, the carotenoid content was determined by spectrophotometry, and the total acid content of carrot was determined by acid-base indicator titration method with reference to GB12456-2021 "National Food Safety Standard Determination of Total Acid in Food", the soluble sugar content was determined by anthrone-sulfuric acid colorimetry, the total phenol content was determined by Folin-phenol method, and the flavonoid content was determined by spectrophotometry.

[0013] The beneficial effects of the present invention are:

[0014] 1. The present invention uses contact glow discharge plasma activated water to treat damaged carrot taproots, and the high-energy active substances therein degrade quickly. Therefore, the application in production will not cause safety impact on human health and will not cause environmental pollution.

[0015] 2. The wound healing rate of damaged carrot taproots after being treated with glow discharge plasma activated water is accelerated, the nutritional quality is significantly improved, and the treatment efficiency is high.

[0016] 3. The equipment used in the present invention is simple and easy to operate, and the electrolyte calcium chloride is cheap, which has good promotion and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a graph showing the effect of different concentrations of plasma-activated water on SPP and lignin deposition at the wound of carrot taproot in Example 1 of the present invention;

[0018] Figure 2 This is a graph showing the effect of different concentrations of plasma-activated water on the thickness of the SPP (A) and lignin (B) cell layers at the wound of carrot taproot in Example 1 of the present invention;

[0019] Figure 3 This is a graph showing the effect of different concentrations of plasma activated water on the hardness of carrot taproot in Example 1 of the present invention;

[0020] Figure 4 This is a diagram showing the effect of plasma activated water prepared at different voltages on SPP and lignin deposition at carrot taproot wounds in Example 2 of the present invention;

[0021] Figure 5Graph showing the effect of plasma activated water prepared at different voltages on the thickness of the SPP (A) and lignin (B) cell layers at the wound of carrot taproot in Example 2 of the present invention;

[0022] Figure 6 This is a graph showing the effect of plasma activated water prepared at different voltages on carrot taproot hardness in Example 2 of the present invention;

[0023] Figure 7 This is a graph showing the effect of plasma-activated water on SPP and lignin deposition at carrot taproot wounds at different treatment times in Example 3 of the present invention;

[0024] Figure 8 This is a graph showing the effect of plasma activated water prepared at different treatment times on the thickness of the SPP (A) and lignin (B) cell layers at the wound of carrot taproot in Example 3 of the present invention;

[0025] Fig. 9 This is a graph showing the effect of plasma activated water prepared at different treatment times on the hardness of carrot taproot in Example 3 of the present invention;

[0026] Fig.10 This is a graph showing the effect of plasma-activated water on SPP and lignin deposition at the wound of carrot taproot after different placement times in Example 4 of the present invention;

[0027] Fig.11 Graph showing the effect of plasma activated water on the thickness of carrot SPP (A) and lignin (B) cell layers after different placement times in Example 4 of the present invention;

[0028] Fig.12 This is a graph showing the effect of plasma activated water on the weight loss rate of carrots after different placement times in Example 4 of the present invention;

[0029] Fig.13 This is a graph showing the effect of plasma activated water on carrot hardness after different placement times in Example 4 of the present invention.

[0030] Fig.14 This is a diagram of the discharge device of the present invention; in the diagram: 1. DC power supply; 2. platinum electrode; 3. condensate water outlet; 4. thermometer; 5. carbon rod; 6. rotor; 7. condensate water inlet; 8. magnetic stirrer. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Embodiment 1:

[0033] 0.5g / L, 1g / L, 2g / L CaCl 2 The solution was added to a glass container, the voltage was adjusted to 550V, and the treatment was carried out for 15 minutes to obtain contact glow discharge plasma activated water with different electrolyte concentrations. The artificially damaged carrots were immediately soaked in contact glow discharge plasma activated water with different electrolyte concentrations for 10 minutes, and then naturally dried and healed in the dark for 5 days. The deposition of SPP and lignin at the damaged site was observed and the thickness of the cell layer was measured. At the same time, the hardness of the damaged carrot taproot was measured. The distilled water soaking treatment was used as the control.

[0034] like Figure 1 and Figure 2 As shown in Figure 2, the SPP fluorescence intensity and lignin coloration of the damaged part of carrots treated with activated water prepared with different concentrations of electrolytes were significantly higher than those of the control group treated with distilled water ( Figure 1 The thickness of the cell layer of deposited SPP and lignin was measured using IS Capture image analysis software, and it was found that 0.5 g / L, 1 g / L, and 2 g / L CaCl 2 The thickness of the SPP cell layer at the wound of carrots in the activated water treatment group was significantly higher than that in the control group by 42.7%, 52.4% and 30.7% respectively. Figure 2 A); the lignin thickness was significantly higher than that of the control group by 8.3%, 42.2% and 24.1% ( Figure 2 B). This shows that activated water made from electrolytes of different concentrations can effectively promote the formation of wound healing sealing layer at the injured part of carrot.

[0035] like Figure 3 As shown in the figure, the hardness of the damaged part of carrots in the activated water treatment group prepared by different concentrations of electrolytes was significantly higher than that in the control group treated with distilled water. 2 The hardness of carrots in the activated water treatment group was 1.46, 2.04 and 1.52 times that of the control group ( Figure 3 ). This shows that activated water made from electrolytes of different concentrations can effectively increase the hardness of carrots and delay their water loss and wilting.

[0036] Embodiment 2:

[0037] like Figure 4 and Figure 5 As shown, 1 g / L CaCl 2The solution was added to a glass container, and the voltage was adjusted to 500V, 550V and 600V, respectively, and the treatment was carried out for 15 minutes to obtain contact glow discharge plasma activated water at different voltages. The artificially damaged carrots were immediately immersed in the contact glow discharge plasma activated water prepared at the above different voltages for 10 minutes, and then naturally dried and healed in the dark for 5 days. The deposition of SPP and lignin at the damaged site was observed and the thickness of the cell layer was measured. At the same time, the hardness of the damaged carrot taproot was measured. The distilled water immersion treatment was used as the control.

[0038] The results showed that the SPP fluorescence intensity and lignin coloration of the damaged part of carrots treated with activated water at different voltages were significantly higher than those of the control group treated with distilled water ( Figure 4 ). The thickness of the cell layer of deposited SPP and lignin was measured using IS Capture image analysis software. It was found that the thickness of the SPP cell layer at the wound of carrot taproot in the activated water treatment group was significantly higher than that in the control group by 30.4%, 93.4% and 12.3% at 500V, 550V and 600V, respectively. Figure 5 A); the thickness of lignin was significantly higher than that of the control group by 36.2%, 68.9% and 23.2% ( Figure 5 B). This shows that the activated water produced under different voltages can effectively promote the formation of callus sealing layer at the injured part of carrot.

[0039] like Figure 6 As shown in the figure, it was also found that the hardness of the damaged part of the carrots in the activated water treatment groups prepared at 500V and 550V voltages was significantly higher than that in the control group treated with distilled water. The hardness of the carrots was significantly higher than that of the control group by 13.9% and 22.3% ( Figure 6 ). This shows that the activated water produced at 500V and 550V voltages can effectively increase the hardness of the damaged part of carrots.

[0040] Embodiment 3:

[0041] 1g / L CaCl 2 The solution was added to a glass container, and the voltage was adjusted to 550 V. Contact glow discharge plasma activated water with treatment times of 10 min, 15 min, and 20 min was prepared. The artificially injured carrots were immediately immersed in contact glow discharge plasma activated water with different treatment times for 10 min, and then naturally dried and healed in the dark for 5 days. The deposition of SPP and lignin at the injured site was observed and the thickness of the cell layer was measured. At the same time, the hardness of the damaged carrot taproot was measured. The distilled water immersion treatment was used as the control.

[0042] like Figure 7 and Figure 8As shown in Figure 2, the SPP fluorescence intensity and lignin coloration of the damaged part of carrots in the activated water treatment group prepared at different treatment times were significantly higher than those in the distilled water treatment control group ( Figure 7 The thickness of the cell layer of deposited SPP and lignin was measured using IS Capture image analysis software. It was found that the thickness of the cell layer of deposited SPP and lignin after treatment with CaCl for 10 and 15 min was 2 The thickness of carrot SPP cell layer in the activated water treatment group was significantly higher than that in the control group by 31.5% and 97.1% ( Figure 8 A); the thickness of lignin was significantly higher than that of the control group by 7.8% and 60.3% ( Figure 8 B). This shows that the activated water prepared when the treatment time is 10min and 15min can effectively promote the formation of callus sealing layer at the injured part of carrot.

[0043] like Fig. 9 As shown in the figure, the texture analyzer showed that the CaCl 2 The hardness of the damaged part of the carrots soaked in activated water was significantly higher than that of the control group treated with distilled water, which was significantly higher than that of the control group by 19.7% and 34.2% ( Fig. 9 ). This shows that the CaCl treatment for 15min and 20min 2 Activated water can effectively increase the hardness of damaged parts of carrots.

[0044] Embodiment 4:

[0045] 1g / L CaCl 2 The solution was added to a glass container, and the voltage was adjusted to 550V. After 15 minutes of treatment, the resulting contact glow discharge plasma activated water was placed for 0 hours, 6 hours and 12 hours, and then soaked in artificially damaged carrot taproots for 10 minutes. After natural drying, the wound was healed in the dark for 5 days, and the deposition of SPP and lignin at the damaged site was observed and the thickness of the cell layer was determined. At the same time, the weight loss rate, hardness and nutritional quality indexes of the damaged carrot taproot were determined. The distilled water soaking treatment was used as the control.

[0046] like Fig.10 and Fig.11 As shown in Figure 2, the SPP fluorescence intensity and lignin coloration of the damaged part of carrots in the activated water treatment group after 0 h and 6 h were significantly higher than those in the distilled water treatment control group ( Fig.10 The thickness of the cell layer of deposited SPP and lignin was measured using IS Capture image analysis software, and it was found that the thickness of the SPP cell layer of carrots in the activated water treatment group after 0h and 6h was significantly higher than that in the control group by 80.9% and 76.4%, respectively ( Fig.11 A); the thickness of lignin was significantly higher than that of the control group by 48.5% and 31.3% ( Fig.11 B). This shows that activated water placed for 0 h and 6 h can effectively promote the formation of callus sealing layer at the injured part of carrot.

[0047] Using the weighing method, we know that the CaCl 2 The weight loss rate of carrots in the plasma activated water treatment group was significantly lower than that in the distilled water control group. This result was significant when the placement time was 0 hours ( Fig.12 ).

[0048] The texture analyzer showed that CaCl 2 When the activated water was placed for 0 h, the hardness of the damaged part of the carrots soaked in water was significantly higher than that of the control group treated with distilled water by 59.3% ( Fig.13 ). After 6 hours, the hardness of the damaged part of the soaked carrots was not significantly different from that of the control group. This shows that the CaCl 2 Activated water can effectively increase the hardness of damaged parts of carrots.

[0049] Table 1 Changes in carrot chromaticity

[0050]

[0051] Table 2 Changes in nutritional quality indicators of carrots

[0052]

[0053] The study also found that CaCl 2 The L, a*, b*, and ΔE of the plasma activated water treatment group were not significantly different from those of the CK group (Table 1), indicating that the activated water did not affect the chromaticity of carrots. 2 The contents of soluble sugar, total phenol, flavonoids and carotenoids in the plasma activated water treatment group were significantly higher than those in the control group, which were 43%, 7.5%, 12% and 24% higher than those in the control group, respectively (Table 2). 2 Plasma activated water can accelerate the healing of carrot taproots after harvest and improve their quality.

[0054] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and range of equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for preparing contact glow discharge plasma activated water for promoting carrot taproot healing, characterized in that: The steps include: Step 1: Place 1L of 1-2g / L calcium chloride solution in a glass container, insert a platinum electrode as an anode and a carbon rod as a cathode, adjust the distance between the anode and cathode to 10-15cm, and control the solution temperature by a circulating water bath; Step 2: Turn on the power supply and adjust the power supply voltage. When the voltage exceeds the critical value, the anode generates a stable glow discharge. Step 3: Seal and store the prepared plasma activated water in a cool and dry place for future use.

2. The method for preparing the contact glow discharge plasma activated water for promoting the healing of carrot taproot according to claim 1, characterized in that: In step 1, the platinum electrode is a platinum wire with a diameter of 0.5-1.0 mm sealed in a sintered quartz tube with the tip exposed; the diameter of the carbon rod is 5-10 mm.

3. The method for preparing the contact glow discharge plasma activated water for promoting the healing of carrot taproot according to claim 1, characterized in that: In step 2, the power supply voltage is 500-550V, and the discharge time is 10-20 minutes.

4. The method for preparing the contact glow discharge plasma activated water for promoting the healing of carrot taproot according to claim 1, characterized in that: In step 3, use within 6 hours.

5. Use of the contact glow discharge plasma activated water for promoting carrot taproot healing prepared by any one of the preparation methods of claims 1 to 4 in promoting carrot taproot healing.

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