Compound grape biological drying accelerator, preparation method and application thereof

Abstract

The present application belongs to the field of material and food technology, and discloses a compound grape drying accelerator, which comprises ethephon, gibberellic acid and ascorbic acid. The drying accelerator is compounded by ethephon, gibberellic acid and ascorbic acid. After the drying accelerator is applied in the preparation of raisins, the water loss rates of Muscat Hamburg and seedless red globe can reach 70% to 79%. Ethephon and gibberellic acid are hormones produced by plants, and ascorbic acid is harmless to human bodies. The drying accelerator improves the drying rate of raisins, shortens the drying time of raisins, effectively retains anthocyanins, antioxidant active substances and total phenol content in raisins, and has the effect of inhibiting the generation of pathogenic and rot-causing microorganisms. In summary, the novel compound biological drying accelerator can effectively improve the drying efficiency, better retain the nutritional components in grapes, and is safer than chemical drying accelerators.

Description

Technical Field

[0001] This invention belongs to the fields of materials and food processing technology, especially green and safe grape drying agents, preparation methods and applications. Background Technology

[0002] In recent years, my country has been continuously striving for high-quality development of the entire grape industry, with the grape planting area in Turpan City, Xinjiang Uygur Autonomous Region, exceeding 42,000 hectares. 2 Grapes account for about 30% of the total grape planting area in Xinjiang and about 5% of the total grape planting area in China; their output exceeds 1.6 million tons, accounting for about 40% of the total grape planting area in Xinjiang and about 8% of the total grape output in China. Grapes are rich in minerals such as calcium, potassium, phosphorus, and iron, as well as various vitamins B1, B2, B6, and anthocyanins, and also contain a variety of amino acids needed by the human body. In addition to fresh grapes, the processing of grapes is also very important. Raisins have a low water content, and most of the nutrients in grapes are concentrated in raisins. Raisins have a sweet and sour taste and a soft and chewy texture, making them very popular. With the improvement of living standards, consumers have also increased their requirements for the quality and variety of raisins. Generally, large, seedless raisins with uniform color and aroma are more favored by consumers.

[0003] Turpan grapes are fully ripe by August, and raisins are dried in mid-to-late August. Fresh grapes take 40-50 days to dry before becoming raisins. Traditional grape drying methods mainly include air-drying in drying rooms and natural sun-drying. Air-dried raisins are bright green, cleaner, and have a better taste, but the drying time is long, and for grape varieties with larger individual berries, drying is difficult and the color is less uniform. Natural sun-drying requires simpler conditions and is faster, but the raisins have a poorer color, mostly reddish-brown or brown. Also, the windy and sandy conditions in Xinjiang during the drying period result in higher dust content in the raisins, leading to poorer hygiene. Furthermore, to improve drying efficiency, farmers often use grape drying agents. Commercially available grape drying agents mainly consist of alkaline substances such as sodium carbonate, potassium hydroxide, and sodium hydroxide. Excessive use can cause the loss of anthocyanins and phenolic substances in grapes and reduce their antioxidant capacity. In particular, there is a problem of excessive residues, posing a threat to the health of sensitive individuals. There is an urgent need to alleviate and avoid the problems caused by chemical drying agents through technological improvements and product innovation.

[0004] The search revealed the following patent publications related to this invention's patent application:

[0005] Compared with Patent 1: Regarding the aforementioned sun-drying method for processing raisins, which has the problem of strong winds and sandstorms in the Turpan region during the drying period, resulting in high sand and dust content in the processed raisins and poor hygiene, the patent publication - A Grape Drying Agent and its Preparation Method (CN202010565320.7, authorized on December 7, 2005) describes a grape drying agent with the following weight percentage composition: potassium hydroxide 1.26-3.4%, sodium carbonate 72-84%, edible oil 9.5-10.7%, alum or sodium hydroxide 0.5-0.9%. Its characteristic is that it also contains the following weight percentage composition: ethanol 9.4-13%, magnesium sulfate or calcium sulfate 1-2%, ethyl acetate 1.25-2.5%, with the sum of the above component percentages being 100%.

[0006] The problems are as follows:

[0007] 1. This method will damage the structure of the grape skin, resulting in the loss of anthocyanins and phenolic substances and a decrease in antioxidant capacity during the subsequent drying process.

[0008] 2. The large-scale use of chemical drying agents in industrial production can lead to excessive residues, posing a threat to consumer health.

[0009] 3. The main components of commercially available chemical drying agents are alkaline substances such as sodium carbonate, potassium hydroxide, and sodium hydroxide, which may cause environmental pollution after application.

[0010] Comparison Patent 2: Addressing the issues of long drying times, difficulty in drying grapes, and poor color in traditional raisin processing methods, patent publication – A Raisin Processing Method and its Pre-treatment Device (CN201710545309.2, authorized January 31, 2023) – discloses a raisin processing method and its pre-treatment device. This method involves trimming fresh grapes into individual pieces, removing the waxy coating from the grape surface through a rolling motion of 5-10 minutes at a speed of 3-6 r / min, followed by hot air drying after rolling. For 3-5 minutes, physical dewaxing effectively removes wax and avoids the residue of secondary pollutants such as chemical drying agents. Then, hot air drying is carried out for 1-10 days at a temperature of 30℃-50℃, which cleans the surface of the grapes and reduces their moisture content. After pretreatment, the grapes are dried using microwave hot air coupling drying with a microwave power of 300W-800W and a hot air temperature of 45℃-65℃. This heats the grapes from the inside out, thereby improving the heat and mass transfer rate and greatly increasing the drying rate. At the same time, it effectively preserves the color, flavor, and nutritional components of the finished raisins.

[0011] The problems are as follows:

[0012] 1. Although it improves production efficiency, the cost and technical requirements of microwave drying are too high, and the operation is complicated.

[0013] 2. This patent increases the water loss rate by removing grape wax, but grape wax has antioxidant, laxative, nutritional, immune-boosting, and eye-protecting effects and benefits. Removing it will reduce the nutritional value of the grape itself.

[0014] Countermeasures: Apply some green and safe biological regulators to prepare drying agents. While ensuring safe use, these agents can meet the needs of various production processes, protect the structure of raisins from damage, reduce nutrient loss, better preserve nutrients within the raisins themselves, prevent nutrient release and subsequent contact with air, thus avoiding oxidative degradation, and protect the color, preventing browning caused by phenolic acid degradation.

[0015] By comparison, the present invention patent application is fundamentally different from the aforementioned patent publications. Summary of the Invention

[0016] The purpose of this invention is to overcome the shortcomings of the prior art and provide a compound grape biological drying agent, its preparation method, and its application.

[0017] The technical solution adopted by this invention to solve its technical problem is:

[0018] A compound grape biological drying agent, wherein the drying agent comprises ethephon, gibberellic acid and ascorbic acid.

[0019] The preparation method of the compound grape biological drying agent as described above involves compounding ethephon, gibberellic acid, and ascorbic acid.

[0020] Furthermore, it includes the following steps:

[0021] (1) Preparation of ethephon solution: Prepare an ethephon solution with an effective ingredient content of 0.16%-0.27% by mass, which is working solution 1;

[0022] (2) Preparation of gibberellic acid solution: Prepare a gibberellic acid solution with an effective ingredient content of 0.001%-0.005% by mass. This is working solution 2.

[0023] (3) Preparation of ascorbic acid solution: Prepare an ascorbic acid solution with an effective ingredient content of 0.05%-0.1% by mass, which is working solution 3;

[0024] (4) Mix the prepared working solution 2 and working solution 3 thoroughly at a volume ratio of 1:1, and record it as mixture 1.

[0025] (5) Mix the mixture 1 and the working solution 1 thoroughly at a volume ratio of 1:1 to obtain the compound grape biological drying agent.

[0026] The application of the compound grape biological drying agent described above in the preparation of dried fruits and vegetables.

[0027] The method for preparing dried fruits and vegetables using the compound grape bio-dried agent described above includes the following steps:

[0028] Soak the grapes in the compound biological drying agent for 1 minute, then quickly remove them.

[0029] The processed grape samples were placed in an oven and dried continuously for 36-48 hours, simulating the drying rooms in Xinjiang.

[0030] Furthermore, the specific steps are as follows:

[0031] (1) Wipe the grapes dry after washing;

[0032] (2) Preparation of ethephon dilution: Prepare an ethephon solution with an effective ingredient content of 0.16%-0.27% by mass to obtain ethephon dilution, which is working solution 1;

[0033] (3) Preparation of gibberellic acid solution: Prepare a gibberellic acid solution with an effective ingredient content of 0.001%-0.005%, which is working solution 2;

[0034] (4) Preparation of ascorbic acid solution: Prepare an ascorbic acid solution with an effective ingredient content of 0.05%-0.1% by mass. This is working solution 3.

[0035] (5) Mix the prepared working solution 2 and working solution 3 thoroughly at a volume ratio of 1:1, and record it as mixture 1.

[0036] (6) Mix the mixture 1 and the working solution 1 thoroughly at a volume ratio of 1:1 to obtain the compound grape biological drying agent;

[0037] (7) Soak the grapes in the compound grape biological drying agent for 1 minute and then quickly remove them;

[0038] (8) Place the treated grape samples into an oven and use the oven to simulate the drying room in Xinjiang. The actual temperature inside the oven is 40℃-45℃, and the drying is carried out continuously for 36-48 hours.

[0039] The advantages and positive effects of this invention are as follows:

[0040] 1. The drying agent of this invention is a compound of ethephon, gibberellic acid, and ascorbic acid, which is green, safe, and has no side effects. Ethephon and gibberellic acid are plant hormones and are harmless to humans. Plant hormones are small molecule signaling substances within plants, which only play a role in transmitting information about plant growth and development and do not participate in the actual "construction" of cells. Human cell membranes do not have the devices to receive these signaling molecules, and therefore will not "respond." Meanwhile, ascorbic acid has antioxidant properties, can inhibit browning of grape skins during the drying process, and is harmless to humans.

[0041] 2. After grapes were treated with the grape biological drying agent of this invention, the water loss rate after baking at 45°C for 36 hours was 1.11 times that of the control group, and there was no significant difference compared with the treatment with chemical drying agents. This indicates that the grape biological drying agent can shorten the drying time by about 10%, which is about 3-5 days shorter than the drying time in a simple air-drying room (30-45 days). The drying rate is comparable to that of chemical drying agents.

[0042] 3. The grape biological drying agent of this invention can increase the antioxidant capacity of grapes by about 6% (expressed as DPPH free radical scavenging rate), inhibit browning of raisins, and maintain good flavor and commercial value. After using the compound grape biological drying agent prepared by this invention, the DPPH content of raisins (1.71 mmol / g) is 1.06 times that of the control group (1.69 mmol / g).

[0043] 4. This invention, based on the traditional method of raisin preparation using drying rooms, applies a green, safe, and highly efficient compound grape biological drying agent. This reduces the damage to the grape surface structure caused by existing chemical drying agents, lowers the probability of microbial infection, and minimizes nutrient loss in the grapes. It can achieve a raisin production rate comparable to that of raisins prepared using chemical drying agents combined with drying rooms. This compound drying agent preparation method is simple, efficient, and safe, making it more suitable for the basic and simple production methods of local residents. Attached Figure Description

[0044] Figure 1 The images show a comparison of scanning electron microscope (SEM) images of raisins prepared using a chemical drying agent and a compound biological drying agent prepared in Example 1, as shown in the chemical drying agent treatment (A) and the biological drying agent treatment (B).

[0045] Figure 2 The graph shows the DPPH measurement results of the control group, chemical drying agent group, and biological drying agent group after baking for 36 hours in Example 1 of this invention; wherein, the DPPH free radical scavenging activity is expressed as the number of micromoles of Trolox equivalent per gram of sample (μmol TE / g);

[0046] Figure 3The graph shows the TPC determination results of the control group, chemical drying agent group, and biological drying agent group after baking for 36 hours in Example 1 of the present invention; where TPC is expressed as the number of milligrams of GA equivalent per gram of sample (mg GAE / g);

[0047] Figure 4 The graph shows the TFC determination results of the control group, chemical drying agent group, and biological drying agent group after baking for 36 hours in Example 1 of the present invention; where TFC is expressed as the number of milligrams of catechin equivalent per gram of sample (mg CE / g);

[0048] Figure 5 This is a color comparison diagram of raisins prepared using two drying agents in Example 2 of the present invention; wherein, raisins treated with chemical drying agent (C) and raisins treated with compound biological drying agent (D) are shown.

[0049] Figure 6 The graph shows the DPPH measurement results of the control group, chemical drying agent group, and biological drying agent group after baking for 36 hours in Example 2 of the present invention; wherein, the DPPH free radical scavenging activity is expressed as the number of micromoles of Trolox equivalent per gram of sample (μmol TE / g);

[0050] Figure 7 The graph shows the TPC determination results of the control group, chemical drying agent group, and biological drying agent group after baking for 36 hours in Example 2 of the present invention; where TPC is expressed as the number of milligrams of GA equivalent per gram of sample (mg GAE / g);

[0051] Figure 8 The graph shows the TFC determination results of the control group, chemical drying agent group, and biological drying agent group after baking for 36 hours in Example 2 of the present invention; where TFC is expressed as the number of milligrams of catechin equivalent per gram of sample (mg CE / g). Detailed Implementation

[0052] The present invention will be further described below with reference to the embodiments. The following embodiments are descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0053] The various experimental operations involved in the specific embodiments are all conventional techniques in the field. For parts not specifically annotated in this document, those skilled in the art can refer to various commonly used reference books, scientific and technological documents or related instructions and manuals prior to the filing date of this invention to carry out the operations.

[0054] A compound grape biological drying agent, wherein the drying agent comprises ethephon, gibberellic acid and ascorbic acid.

[0055] The preparation method of the compound grape biological drying agent as described above involves compounding ethephon, gibberellic acid, and ascorbic acid.

[0056] Preferably, the steps include:

[0057] (1) Preparation of ethephon solution: Prepare an ethephon solution with an effective ingredient content of 0.16%-0.27% by mass, which is working solution 1;

[0058] (2) Preparation of gibberellic acid solution: Prepare a gibberellic acid solution with an effective ingredient content of 0.001%-0.005% by mass. This is working solution 2.

[0059] (3) Preparation of ascorbic acid solution: Prepare an ascorbic acid solution with an effective ingredient content of 0.05%-0.1% by mass, which is working solution 3;

[0060] (4) Mix the prepared working solution 2 and working solution 3 thoroughly at a volume ratio of 1:1, and record it as mixture 1.

[0061] (5) Mix the mixture 1 and the working solution 1 thoroughly at a volume ratio of 1:1 to obtain the compound grape biological drying agent.

[0062] The application of the compound grape biological drying agent described above in the preparation of dried fruits and vegetables.

[0063] The method for preparing dried fruits and vegetables using the compound grape bio-dried agent described above includes the following steps:

[0064] Soak the grapes in the compound biological drying agent for 1 minute, then quickly remove them.

[0065] The processed grape samples were placed in an oven and dried continuously for 36-48 hours, simulating the drying rooms in Xinjiang.

[0066] Furthermore, the specific steps are as follows:

[0067] (1) Wipe the grapes dry after washing;

[0068] (2) Preparation of ethephon dilution: Prepare an ethephon solution with an effective ingredient content of 0.16%-0.27% by mass, which is working solution 1;

[0069] (3) Preparation of gibberellic acid solution: Prepare a gibberellic acid solution with an effective ingredient content of 0.001%-0.005%, which is working solution 2;

[0070] (4) Preparation of ascorbic acid solution: Prepare an ascorbic acid solution with an effective ingredient content of 0.05%-0.1% by mass. This is working solution 3.

[0071] (5) Mix the prepared working solution 2 and working solution 3 thoroughly at a volume ratio of 1:1, and record it as mixture 1.

[0072] (6) Mix the mixture 1 and the working solution 1 thoroughly at a volume ratio of 1:1 to obtain the compound grape biological drying agent;

[0073] (7) Soak the grapes in the compound biological drying agent for 1 minute and then quickly remove them;

[0074] (8) Place the treated grape samples into an oven and use the oven to simulate the drying room in Xinjiang. The actual temperature inside the oven is 40℃-45℃. Dry continuously for 36-48 hours.

[0075] Specifically, the relevant preparation and testing methods are as follows:

[0076] Example 1

[0077] A method for preparing dried fruits and vegetables using a compound grape bio-dried agent includes the following steps:

[0078] Select fresh, mature, seedless grapes with a diameter of 1.0-1.5cm that are free from rot, pests, and mold. Rinse them with running water to remove dirt and mucus from the surface of the grapes. Take about 50g of the selected grapes as a portion and soak each portion of grapes in distilled water (control group), chemical drying agent, and compound grape biological drying agent, respectively. After 1 minute, quickly remove them, dry the surface moisture, and record the weight m0.

[0079] Grapes soaked in distilled water, chemical and biological drying agents respectively were then baked in an oven at 43°C for 36 hours. The weight of the grapes after baking, m1, was recorded, and the water loss rate of the raisins was calculated using the following formula:

[0080]

[0081] Each treatment group was performed in triplicate, and the data for each indicator were expressed as averages.

[0082] The chemical drying agent is prepared at a concentration of 2.33% (mass percentage) according to the usage instructions. The preparation method of the compound grape biological drying agent includes the following steps:

[0083] (1) Preparation of ethephon solution: Prepare an ethephon solution with an effective ingredient content of 0.2% by mass, which is working solution 1;

[0084] (2) Preparation of gibberellic acid solution: Prepare a gibberellic acid solution with an effective ingredient content of 0.002% by mass, which is working solution 2;

[0085] (3) Preparation of ascorbic acid solution: Prepare an ascorbic acid solution with an effective ingredient content of 0.08% by mass, which is working solution 3;

[0086] (4) Mix the prepared working solution 2 and working solution 3 thoroughly at a volume ratio of 1:1, and record it as mixture 1.

[0087] (5) Mix the mixed solution 1 and the working solution 1 thoroughly at a volume ratio of 1:1 to obtain the compound grape biological drying agent.

[0088] Table 1. Effects of compound grape biological drying agents on water loss rate and color change of raisins.

[0089]

[0090] L in the table ＊ Represents brightness, a ＊ Represents red-green hue, b ＊ It represents the shade of yellow-blue.

[0091] Table 1 shows that the average water loss rate of the samples treated with the biological drying agent was approximately 70.71%, which was about 1.13 times that of the control group (62.39%). The traditional drying method in Turpan, Xinjiang, generally requires 30-45 days, and the water loss rate was not significantly different from that of the chemical drying agent treatment (70.70%). This indicates that the biological drying agent can shorten the drying time by about 10%, and by about 3-5 days compared to simple air drying in a drying room (30-45 days), achieving a drying rate comparable to that of chemical drying agents.

[0092] Scanning electron microscopy results of raisin peels are as follows Figure 1 As shown, raisins treated with chemical drying agents have numerous cracks on their surface, but raisins treated with the compound biological grape drying agent of this invention show almost no damage to their surface, confirming the powerful destructive effect of chemical drying agents on grape surface tissue.

[0093] In this example, the DPPH radical scavenging rate, TPC, and TFC results are as follows: Figure 2 , Figure 3 and Figure 4 As shown, after treatment with the chemical drying agent, the grape skin is damaged, making it easier to extract phenolic acids and flavonoids from the grapes under the same extraction method. Therefore, the DPPH free radical scavenging rate, phenolic acid, and flavonoid content of the raisins are all higher than those obtained with the compound grape biological drying agent of this invention. However, the color acceptability of raisins obtained with the chemical drying agent is lower than that obtained with the biological drying agent. The raisins obtained with the biological drying agent are closer to the L*, a*, and b* values ​​of the control group. This is because phenolic acids and flavonoids are oxidized by polyphenol oxidase under oxygen exposure to produce brown substances (Table 1). Figure 5 ).

[0094] Comparative Example 1

[0095] The method for preparing dried fruits and vegetables as described in Example 1 includes the following steps:

[0096] Select fresh, seedless grapes of moderate ripeness with a diameter of 1.0-1.5 cm, free from rot, pests, and mold. Rinse the grapes under running water to remove dirt and mucus, drain, and dry them. Take approximately 50g of the selected grapes as a portion and immerse each portion in distilled water (control group), gibberellic acid solution, and ethephon solution, respectively. After 1 minute, quickly remove the grapes, let them air dry, and record the weight m0.

[0097] Grapes soaked in distilled water, gibberellic acid solution, and ethephon solution respectively were then baked in an oven at 43°C for 48 hours. The weight of the grapes after baking, m1, was recorded. The water loss rate of the raisins was calculated using the following formula:

[0098]

[0099] Each treatment was repeated three times, and all metrics were expressed as averages.

[0100] The solution preparation methods for the four treatments in the comparative examples include the following steps:

[0101] (1) A control group was prepared according to Example 1.

[0102] (2) Prepare a gibberellic acid solution with an effective ingredient content of 0.002%.

[0103] (3) Prepare an ethephon solution with an effective ingredient content of 0.2% by mass.

[0104] (4) Prepare the biological drying agent group according to Example 1.

[0105] The calculation of water loss rate is the same as in Example 1.

[0106] Table 2 Effects of gibberellic acid and ethephon solution on water loss rate of raisins

[0107]

[0108] Table 2 shows that the raisins treated with 0.2% ethephon alone had a 10.86% higher water loss rate than the control group, while the raisins treated with 0.002% gibberellic acid alone had only a 7.63% higher water loss rate than the control group. This indicates that the 0.2% ethephon solution treatment was more effective, hence the use of ethephon as the main component of the biological drying agent. Furthermore, the grapes treated with the biological drying agent prepared in Example 1 achieved a water loss rate of 79.41%, significantly better than the other three treatments.

[0109] Meanwhile, comparing Example 1 and Comparative Example 1, it can be seen that the components of the compound grape biological drying agent of the present invention, ethephon and gibberellic acid, have a synergistic effect, which can better improve the drying rate of raisins and shorten the drying time.

[0110] Example 2

[0111] A method for preparing dried fruits and vegetables using a compound grape biological drying agent was described. Grapes were treated according to the method in Example 1, and the water loss rate was measured.

[0112] Grapes soaked in distilled water, chemical and biological drying agents respectively were baked in an oven at 45°C for 36 hours. The weight of the grapes after surface moisture was dried was recorded as m0, and the weight of the grapes after baking was recorded as m1. The water loss rate of the raisins was calculated using the following formula:

[0113]

[0114] Each treatment group was performed in triplicate, and the data for each indicator were expressed as averages.

[0115] The chemical drying agent is prepared at a concentration of 2.33% (mass percentage) according to the usage instructions. The preparation method of the compound grape biological drying agent includes the following steps:

[0116] (1) Preparation of ethephon solution: Prepare an ethephon solution with an effective ingredient content of 0.25% by mass, which is working solution 1;

[0117] (2) Preparation of gibberellic acid solution: Prepare a gibberellic acid solution with an effective ingredient content of 0.001% by mass, which is working solution 2;

[0118] (3) Preparation of ascorbic acid solution: Prepare an ascorbic acid solution with an effective ingredient content of 0.05% by mass, which is working solution 3;

[0119] (4) Mix the prepared working solution 2 and working solution 3 thoroughly at a volume ratio of 1:1, and record it as mixture 1.

[0120] (5) Mix the mixture 1 and the working solution 1 thoroughly at a volume ratio of 1:1 to obtain the compound grape biological drying agent.

[0121] Table 3 shows the water loss rate of grapes after baking treated with the compound grape bio-dried agent prepared in Example 2.

[0122]

[0123] L in the table ＊ Represents brightness, a ＊ Represents red-green hue, b ＊ It represents the shade of yellow-blue.

[0124] Table 3 shows that the average water loss rate of the samples treated with the biological drying agent was approximately 72.82%, which was about 1.11 times that of the control group (65.49%). The traditional drying method in Turpan, Xinjiang, generally requires 30-45 days. The water loss rate of the samples treated with the chemical drying agent (72.08%) showed no significant difference, indicating that the biological drying agent can shorten the drying time by about 7%, and by about 2-4 days compared to simple air drying in a drying room (30-45 days). The drying rate is comparable to that of chemical drying agents.

[0125] In this example, the DPPH radical scavenging rate, TPC, and TFC results are as follows: Figure 6 , Figure 7 and Figure 8 As shown, the DPPH free radical scavenging rate, phenolic acid, and flavonoid content of the raisins were all higher than those prepared with the compound grape biological drying agent of this invention. However, the color acceptability of raisins prepared with chemical drying agents was lower than that prepared with biological drying agents, and the L*, a*, and b* values ​​of raisins prepared with biological drying agents were closer to those of the control group (Table 3).

[0126] All of the above demonstrates that the compound grape biological drying agent prepared by this invention is effective and can be applied to production and processing.

[0127] Commercially available grape drying agents are composed of chemical components such as potassium hydroxide, sodium carbonate, sodium hydroxide, and ethanol. While they can improve production efficiency, they damage the grape's structure and nutritional value, leading to browning and nutrient loss, thus affecting its color. Excessive use of grape drying agents can result in excessive residues, posing food safety risks. Furthermore, the inability to properly recycle grape drying agents can also cause environmental pollution.

[0128] This invention is a compound grape biological drying agent prepared from green and safe biological regulators. It meets the needs of various production processes while ensuring safe use. It also protects the skin structure of fruits and vegetables from damage, reduces the precipitation of phenolic acids and flavonoids, and reduces the formation of dark brown substances after contact with air. This protects the color of the grapes, improves the efficiency of grape drying, and ensures food and environmental safety.

[0129] Although embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations, and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, the scope of the invention is not limited to the contents disclosed in the embodiments.

Claims

1. A compound grape biological drying agent, characterized in that: The drying agents include ethephon, gibberellic acid, and ascorbic acid; The method for preparing the compound grape biological drying agent is described in that the method involves compounding ethephon, gibberellic acid, and ascorbic acid. Includes the following steps: (1) Preparation of ethephon solution: Prepare an ethephon solution with an effective ingredient content of 0.16%-0.25% by mass, which is working solution 1; (2) Preparation of gibberellic acid solution: Prepare a gibberellic acid solution with an effective ingredient content of 0.001%-0.005% by mass, which is working solution 2; (3) Preparation of ascorbic acid solution: Prepare an ascorbic acid solution with an effective ingredient content of 0.05%-0.1% by mass, which is the working solution 3; (4) Mix the prepared working solution 2 and working solution 3 thoroughly at a volume ratio of 1:1, and record it as mixture 1; (5) Mix the mixed solution 1 and the working solution 1 thoroughly at a volume ratio of 1:1 to obtain the compound grape biological drying agent.

2. The application of the compound grape biological drying agent as described in claim 1 in the preparation of raisins.

3. A method for preparing raisins using the compound grape biological drying agent as described in claim 1, characterized in that: Includes the following steps: Soak the grapes in the compound biological drying agent for 1 minute, then quickly remove them. The processed grape samples were placed in an oven and dried continuously for 36-48 hours, simulating the drying rooms in Xinjiang.

4. The method according to claim 3, characterized in that: The specific steps are as follows: (1) Wipe the grapes dry after washing; (2) Preparation of ethephon dilution: Prepare an ethephon solution with an effective ingredient content of 0.16%-0.25% by mass, which is working solution 1; (3) Preparation of gibberellic acid solution: Prepare a gibberellic acid solution with an effective ingredient content of 0.001%-0.005%, which is working solution 2; (4) Preparation of ascorbic acid solution: Prepare an ascorbic acid solution with an effective ingredient content of 0.05%-0.1% by mass, which is working solution 3; (5) Mix the prepared working solution 2 and working solution 3 thoroughly in a volume ratio of 1:1, and record it as mixture 1; (6) Mix the mixture 1 and the working solution 1 thoroughly at a volume ratio of 1:1 to obtain the compound grape biological drying agent; (7) Soak the grapes in the compound biological drying agent for 1 minute and then quickly remove them; (8) Place the treated grape samples into an oven and use the oven to simulate the drying room in Xinjiang. The internal temperature of the oven is 40℃-45℃. Dry continuously for 36-48 hours.

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