CN108514026A - A kind of fresh-cut fruit and vegetable composite preservative and its application method - Google Patents

Abstract

The invention discloses a composite preservative for fresh-cut fruits and vegetables and an application method thereof, belonging to the technical field of fruit and vegetable processing. In the present invention, the fresh-cut fruits and vegetables are soaked for a short time in a composite soaking liquid composed of ascorbic acid, cinnamon essential oil, β-cyclodextrin and chitosan, and then sprayed with konjac glucomannan and carrageenan composite gel after drying. , the fresh-cut fruits and vegetables are processed through the secondary composite fresh-keeping process, and natural slow-release fungicides, water-retaining agents and double-layer protective films are formed on the surface of fruits and vegetables to effectively protect the surface of fresh-cut fruits and vegetables, and solve the deterioration and dehydration of fresh-cut fruits and vegetables in the fresh-keeping process and oxidation issues.

Description

A composite preservative for fresh-cut fruits and vegetables and its application method

technical field

The invention relates to the technical field of fruit and vegetable processing, in particular to a composite preservative for fresh-cut fruits and vegetables and a method for using the same.

Background technique

Fresh-cut fruits and vegetables, also known as lightly processed fruits and vegetables, cut fruits and vegetables, and conditioned fruits and vegetables, originated in the United States in the 1950s, mainly to meet consumers' ready-to-eat needs. It refers to processed fruits and vegetables that are processed by consumers or the catering industry for immediate consumption after fresh fruits and vegetables are graded, cleaned, peeled, trimmed, cut, packaged, etc. Fresh-cut products first appeared in American retail stores, but their development was limited due to poor product quality and shelf life. However, with the rapid economic development and technological innovation in the United States, the fresh-cut industry began to break through the bottleneck and develop rapidly. For example, the so-called "peeled potato industry" appeared. At that time, the catering industry and food service industry in the United States needed a potato that was both fresh and easy to use. At first, only peeled whole potatoes were supplied, and then various slices, such as small Cubes, chips, chips, and more are all available. Not only that, the fresh-cut fruit and vegetable industry has also developed, which has led to the commercial production of fresh-cut products in the United States. At present, the production of fresh-cut fruits and vegetables has formed a complete system in developed countries in Europe and the United States, which is manifested in technical standardization, product standardization, advanced equipment, market networking and modern management. The marketization of fresh-cut fruits and vegetables in my country started relatively late. It was not until the 1990s, with the improvement of people's living standards, the acceleration of the pace of life and the segmentation of the fruit and vegetable market, that people began to pay attention to fresh-cut fruits and vegetables when purchasing. . In recent years, due to the rapid development of the Internet, fresh-cut fruits and vegetables not only occupy an important position in the catering industry, but also become a leader in the retail industry, especially in first-tier cities such as Beijing, Shenzhen, and Shanghai. Fresh-cut fruits and vegetables have also become an indispensable way of catering for enterprises, schools, airlines, and high-speed rail. It not only satisfies nutritional, scientific, and healthy catering, but also allows consumers to adapt to the fast-paced modern life. In 2015, my country included fresh-cut fruits and vegetables in the scope of production license management. Therefore, although my country's fresh-cut fruit and vegetable industry started late, it has developed very rapidly and has broad market prospects.

At present, the overall technical level of my country's fresh-cut fruit and vegetable industry is still very weak. The mechanical treatment of fresh-cut fruits and vegetables in the processing process damages the fruit and vegetable tissue, and there are widespread problems such as surface browning, pulp softening and nutrient loss, which reduce product quality. And further led to the reduction of product shelf life. The existing fresh-cut fruit and vegetable preservation methods in China include chemical agent method, low-temperature refrigeration method, heat treatment method, modified atmosphere method, irradiation method, film coating method, etc., but the application of these methods all has various problems, or can only solve them. Some aspects of fresh-cut fruits and vegetables, such as chemical methods can prevent browning and inhibit microorganisms but cannot prevent water evaporation, heat treatment can also prevent browning and inhibit microorganisms but will cause texture softening, irradiation can kill the surface However, microorganisms can aggravate browning, and the coating method also has problems such as uneven coating. There is an urgent need to study an effective method to protect the cut surface of fresh-cut fruits and vegetables, which can simultaneously reduce water loss and oxidative browning, and reduce microbial pollution, so as to maintain the sensory quality and nutritional quality of fresh-cut fruits and vegetables, extend shelf life, and increase economic value. .

Contents of the invention

In order to make up for the deficiencies of the prior art, the present invention provides an all-round fresh-cut fruit and vegetable composite preservative and its application method, which solves the problems of deterioration, dehydration and oxidation in the fresh-cut process of fresh-cut fruits and vegetables in the prior art.

The present invention is achieved through the following technical solutions:

A composite preservative for fresh-cut fruits and vegetables, which is special in that it includes a soaking solution and a spray gel solution; the soaking solution is made of the following raw materials: low-viscosity chitosan, β-cyclodextrin, cinnamon essential oil, ascorbic acid , deionized water; the spray gel solution is made of the following raw materials: konjac glucomannan, carrageenan, and deionized water.

Wherein, every 100 parts of soaking liquid includes 0.5-1.5 parts of low-viscosity chitosan, 1.5-3 parts of beta-cyclodextrin, 0.5-2 parts of cinnamon essential oil, 1-2.5 parts of ascorbic acid, and the rest is deionized water.

The configuration method of the soaking liquid is as follows: add low-viscosity chitosan and β-cyclodextrin to deionized water and heat to 50-60°C, stir and dissolve, add cinnamon essential oil to seal, and stir at 50-60°C for 2-6h, Then add ascorbic acid to dissolve and get soaking solution.

In the present invention, in the soaking liquid formula, ascorbic acid plays a color-protecting role and prevents the generation of oxidative browning. Cinnamon essential oil is the essential oil with the best antibacterial effect at present and can effectively inhibit most microorganisms. β-cyclodextrin has two functions. One is that it can embed cinnamon essential oil to release cinnamon essential oil slowly, inhibit bacteria for a longer time, and at the same time cover up the slight pungent smell of cinnamon essential oil. The other is that it can retain water. β-cyclodextrin A large number of hydroxyl groups on the surface of dextrin can form hydrogen bonds with water to keep the water from volatile. The interaction between the positive charge of the amino group on the low-viscosity chitosan molecule and the negative charge on the bacterial cell membrane has antibacterial and bactericidal effects. The low-viscosity chitosan also has good film-forming properties, and its film layer has permeability. Water resistance can increase the penetration resistance of various gas molecules, forming a micro-atmosphere adjustment environment, increasing the carbon dioxide content and reducing the oxygen content in the fruit and vegetable tissues, inhibiting the respiratory metabolism and water loss of fruits and vegetables, and slowing down the process of fruit and vegetable tissues and Structural aging.

The viscosity of the low-viscosity chitosan in the soaking solution is 100-200 mPa·s.

The cinnamon essential oil in the soaking liquid is extracted by steam distillation, and the cinnamaldehyde content is >65%.

The mass ratio of konjac glucomannan and carrageenan in the spray gel solution is 5.5:4.5; konjac glucomannan and carrageenan mixed gel has better texture than konjac glucomannan or carrageenan alone And film-forming effect, konjac glucomannan is very easy to syneresis, forming a strong film toughness, carrageenan film-forming concentration is low, but the film toughness is not enough, the mixture of the two at a ratio of 5.5:4.5 to form a gel film has the best effect.

The pH value of the spray gel solution is adjusted to 9-11 by deionized water.

The using method of a kind of fresh fruit and vegetable composite antistaling agent of the present invention, its special feature is: comprise the following steps:

(1) Soaking liquid configuration: Add chitosan and β-cyclodextrin to deionized water and heat to 50-60°C and stir to dissolve, add cinnamon essential oil to seal, stir at 50-60°C for 2-6h, then add ascorbic acid to dissolve after soaking solution;

(2) Soaking: Soak the prepared fresh-cut fruits and vegetables in the soaking solution for 2-10 minutes, take them out, drain the water, and place them in a ventilated and dry place indoors for 1-2 hours to cool down to room temperature, and the surface is dry without obvious moisture ;

(3) Spray film: Mix konjac glucomannan and carrageenan in proportion, add deionized water to adjust pH, heat to 80-90°C and stir to dissolve, make 2% mixed gel solution, cool down to 60- Spray the gel solution evenly on the surface of soaked fruits and vegetables at 80°C;

(4) Air-drying: the sprayed fruits and vegetables are air-dried at room temperature until there is no obvious moisture on the surface;

(5) Packaging: The processed fresh-cut fruits and vegetables are packaged and then stored.

Wherein, in step (5), the processed fresh-cut fruits and vegetables are packaged with PE plastic wrap or OPP ziplock bags, and then stored at a low temperature of 0-5°C or at room temperature.

The beneficial effects of the present invention are: the present invention adopts the composite antistaling agent technology to comprehensively solve the problems that the incisions of fresh-cut fruits and vegetables are exposed to the air, which may easily cause microbial growth, oxidative browning and water volatilization, and ensure the freshness of fresh-cut fruits and vegetables. In the formulation of the soaking solution, ascorbic acid acts as a color protector and prevents oxidative browning. Cinnamon essential oil is the essential oil with the best antibacterial effect at present and can effectively inhibit most microorganisms. β-cyclodextrin has two functions. One is that it can embed cinnamon essential oil to release cinnamon essential oil slowly, inhibit bacteria for a longer time, and at the same time cover up the slight pungent smell of cinnamon essential oil. The other is that it can retain water. β-cyclodextrin A large number of hydroxyl groups on the surface of dextrin can form hydrogen bonds with water to keep the water from volatile. The interaction between the positive charge of the amino group on the low-viscosity chitosan molecule and the negative charge on the bacterial cell membrane has antibacterial and bactericidal effects. The low-viscosity chitosan also has good film-forming properties, and its film layer has permeability. Water resistance can increase the penetration resistance of various gas molecules, forming a micro-atmosphere adjustment environment, increasing the carbon dioxide content and reducing the oxygen content in the fruit and vegetable tissues, inhibiting the respiratory metabolism and water loss of fruits and vegetables, and slowing down the process of fruit and vegetable tissues and Structural aging.

In order to prevent the unevenness of the chitosan film layer formed by soaking, slow down the outward emission of cinnamon essential oil, and block oxygen, after soaking and drying to form the first protective layer, the chitosan is mixed and coagulated with konjac glucomannan and carrageenan. Glue spraying, konjac glucomannan and carrageenan mixed gel has better texture and film-forming effect than konjac glucomannan or carrageenan alone. Konjac glucomannan is easy to syneresis and forms a film with strong toughness , the carrageenan film-forming concentration is low, but the film toughness is not enough, and the mixture of the two in the ratio of 5.5:4.5 to form a gel film has the best effect. The formed second film layer of the mixed gel can keep the cinnamon essential oil at a relatively high concentration in the film layer for a long period of time, further blocking the volatilization of oxygen and water, and achieving a better fresh-keeping effect.

The antistaling agent and usage method of the present invention can be used for fresh-cut preservation of common fruits such as apples, pears, peaches, apricots, bananas, dragon fruit, kiwi fruit, melons, and cantaloupe, or for strawberries, grapes, mulberries, etc., which are difficult to preserve after harvest. The direct preservation of fruits can also be used for fresh cutting and preservation of vegetables such as potatoes, sweet potatoes, taro, cucumbers, pumpkins, wax gourds, beans, and asparagus.

Detailed ways

The present invention will be described in further detail below in conjunction with specific embodiments, to help those skilled in the art have a more complete, accurate and in-depth understanding of the inventive concept and technical solutions of the present invention, the protection scope of the present invention includes but is not limited to the following examples , Any modifications made to the details and forms of the technical solution of the present invention shall fall within the protection scope of the present invention without departing from the spirit and scope of the present application.

Example 1

Fresh Cut Apple Processing

Preparation of soaking solution: Add 8g of low-viscosity chitosan (viscosity 100-200mPa s, 1%, 20°C) and 20g of β-cyclodextrin to 1000ml of deionized water, heat to 55°C and stir to dissolve, add 10g of cinnamon essential oil and seal it at 55°C Stir at ℃ for 4 hours, then add 20g of ascorbic acid to dissolve and obtain soaking solution.

Soaking: Soak the prepared fresh-cut apples in the above 55°C soaking solution for 2 minutes, take them out, drain the water, and place them in a ventilated and dry place indoors for 1 hour to cool down to room temperature, and the surface is dry without obvious moisture.

Spray film: Mix konjac glucomannan and carrageenan at a ratio of 5.5:4.5, add deionized water to adjust pH = about 10, heat to 85°C and stir to dissolve to make a 2% mixed gel solution. Cool down to 70°C and evenly spray the gel solution onto the surface of soaked fruits and vegetables.

Air-drying: After spraying, the vegetables are air-dried at room temperature until there is no obvious moisture on the surface.

Packaging: Pack the processed fresh-cut apples with PE plastic wrap, and then store them at a low temperature of 0-5°C.

Example 2

Fresh Cut Pear Processing

Preparation of soaking solution: Add 10g of low-viscosity chitosan (viscosity 100-200mPa s, 1%, 20°C) and 20g of β-cyclodextrin to 1000ml of deionized water, heat to 55°C and stir to dissolve, add 10g of cinnamon essential oil and seal it at 55°C Stir at ℃ for 4 hours, then add 10 g of ascorbic acid to dissolve to obtain soaking solution.

Soaking: Soak the prepared fresh-cut pears in the above 55°C soaking solution for 2 minutes, take it out, drain the water, and place it in a ventilated and dry place indoors for 2 hours to cool down to room temperature, and the surface is dry without obvious moisture.

Spray film: Mix konjac glucomannan and carrageenan at a ratio of 5.5:4.5, add deionized water to adjust pH = about 10, heat to 85°C and stir to dissolve to make a 2% mixed gel solution. Cool down to 70°C and evenly spray the gel solution onto the surface of soaked fruits and vegetables.

Air-drying: After spraying, the vegetables are air-dried at room temperature until there is no obvious moisture on the surface.

Packaging: Pack the processed fresh-cut pears with PE plastic wrap, and then store them at room temperature.

Example 3

Fresh Cut Melon Processing

Preparation of soaking solution: Add 10g of low-viscosity chitosan (viscosity 100-200mPa s, 1%, 20°C) and 20g of β-cyclodextrin to 1000ml of deionized water, heat to 55°C and stir to dissolve, add 10g of cinnamon essential oil and seal it at 55°C Stir at ℃ for 4 hours, then add 10 g of ascorbic acid to dissolve to obtain soaking solution.

Soaking: Soak the prepared fresh-cut melon in the above 55°C soaking solution for 4 minutes, take it out, drain the water, and place it in a ventilated and dry place indoors for 2 hours to cool down to room temperature, and the surface is dry without obvious moisture.

Spray film: Mix konjac glucomannan and carrageenan at a ratio of 5.5:4.5, add deionized water to adjust pH = about 10, heat to 85°C and stir to dissolve to make a 2% mixed gel solution. Cool down to 70°C and evenly spray the gel solution onto the surface of soaked fruits and vegetables.

Air-drying: After spraying, the vegetables are air-dried at room temperature until there is no obvious moisture on the surface.

Packaging: Pack the treated fresh-cut melons with PE plastic wrap, and then store them at a low temperature of 0-5°C.

Example 4

Fresh Strawberry Treatment

Preparation of soaking solution: Add 5g of low-viscosity chitosan (viscosity 100-200mPa s, 1%, 20°C) and 20g of β-cyclodextrin to 1000ml of deionized water, heat to 55°C and stir to dissolve, add 10g of cinnamon essential oil and seal it at 55°C Stir at ℃ for 4 hours, then add 10 g of ascorbic acid to dissolve to obtain soaking solution.

Soaking: Soak the prepared fresh strawberries in the above 55°C soaking solution for 8 minutes, take them out, drain the water, and place them in a ventilated and dry place indoors for 1 hour to cool down to room temperature, and the surface is dry without obvious moisture.

Spray film: Mix konjac glucomannan and carrageenan at a ratio of 5.5:4.5, add deionized water to adjust pH = about 10, heat to 85°C and stir to dissolve to make a 2% mixed gel solution. Cool down to 70°C and evenly spray the gel solution onto the surface of soaked fruits and vegetables.

Air-drying: After spraying, the vegetables are air-dried at room temperature until there is no obvious moisture on the surface.

Packaging: Pack the treated strawberries with OPP ziplock bags, and then store them at room temperature.

Example 5

Fresh Cut Potato Chip Processing

Preparation of soaking solution: Add 10g of low-viscosity chitosan (viscosity 100-200mPa s, 1%, 20°C) and 20g of β-cyclodextrin to 1000ml of deionized water, heat to 55°C and stir to dissolve, add 10g of cinnamon essential oil and seal it at 55°C Stir at ℃ for 4 hours, then add 20g of ascorbic acid to dissolve and obtain soaking solution.

Soaking: Soak the prepared fresh-cut potato slices in the above-mentioned 55°C soaking solution for 10 minutes, take it out, drain the water, and put it in a ventilated and dry place indoors for 1.5 hours to let the temperature drop to room temperature, and the surface is dry without obvious moisture.

Spray film: Mix konjac glucomannan and carrageenan at a ratio of 5.5:4.5, add deionized water to adjust pH = about 10, heat to 85°C and stir to dissolve to make a 2% mixed gel solution. Cool down to 70°C and evenly spray the gel solution onto the surface of soaked fruits and vegetables.

Air-drying: After spraying, the vegetables are air-dried at room temperature until there is no obvious moisture on the surface.

Packaging: Pack the processed fresh-cut potato slices with PE plastic wrap, and then store them at room temperature.

Example 6

fresh asparagus treatment

Preparation of soaking solution: Add 5g of low-viscosity chitosan (viscosity 100-200mPa s, 1%, 20°C) and 20g of β-cyclodextrin to 1000ml of deionized water, heat to 55°C and stir to dissolve, add 10g of cinnamon essential oil and seal it at 55°C Stir at ℃ for 4 hours, then add 10 g of ascorbic acid to dissolve to obtain soaking solution.

Soaking: Soak the prepared fresh asparagus in the above 55°C soaking solution for 5 minutes, take it out, drain the water, and place it in a ventilated and dry place indoors for 1 hour to cool down to room temperature, and the surface is dry without obvious moisture.

Spray film: Mix konjac glucomannan and carrageenan at a ratio of 5.5:4.5, add deionized water to adjust pH = about 10, heat to 85°C and stir to dissolve to make a 2% mixed gel solution. Cool down to 70°C and evenly spray the gel solution onto the surface of soaked fruits and vegetables.

Air-drying: After spraying, the vegetables are air-dried at room temperature until there is no obvious moisture on the surface.

Packaging: Pack the processed fresh asparagus in OPP ziplock bags, and then store them at a low temperature of 0-5°C.

Comparative Test

sensory experiment

A 10-point rating system is used. The color, freshness, shape, rottenness and flavor of asparagus are scored according to four grades. The product is excellent, the head and stem are plump, without any blemishes, 10 points, the product with a score of 7 or more is good, still fresh, but slightly flawed, which can be used as a standard for evaluating commercial value, and the head with a score of 5 has water Stain-like, the stem is aged to a certain extent, mild odor, inedible below 3 points. See the table below for specific scoring criteria.

Table 1 Sensory evaluation criteria

Table 2 Sensory score table

It can be seen from the results of sensory quality changes that the sensory quality of asparagus fresh-keeping treated by this method declines slowly under refrigeration conditions, and can play a good fresh-keeping effect. After being treated for 12 days, the asparagus is still very good in sensory, with scores above 8.5. After 18 days, there is a slight change in sensory, and the score is still above 8. After storage for 24 days, there is a significant change in sensory, but it can still be used Consumers accept it, but untreated asparagus has a certain degree of aging and dehydration in the stem portion in 12 days, and there is a significant gap with the processed asparagus in 18 days. After 30 days of refrigeration, the heads of untreated asparagus were wilted and slightly rotten, and the stems were seriously dehydrated, while the heads of asparagus treated with fresh-keeping coating were slightly chlorotic, the stems were slightly dehydrated, and the fresh-keeping effect was more obvious.

Determination of the total number of colonies

The determination method of the total number of colonies refers to GB4789.2-2010. The results are shown in Table 3.

Table 3 Changes in the total number of asparagus colonies

Under refrigerated conditions, untreated asparagus can be observed to be rotten at the incision site after 18 days, and the rot is serious after 24 days. However, the asparagus treated with fresh-keeping coating film did not see microbial growth after 18 days, and only slight dehydration was seen after 30 days, and no corruption was seen, and the fresh-keeping effect was obvious.

Determination of weight loss rate

The weight loss rate is determined according to the following formula:

Table 4 Changes in weight loss rate of asparagus

The dehydration of fruits and vegetables will cause changes in shape, texture, structure and many other aspects. Green asparagus after harvesting has a very high water content, but because of its relatively young tissues, the respiration is very strong, and the water is easily evaporated and lost, resulting in tender asparagus. The stem loses water too quickly, and the fresh-keeping period is greatly shortened. The weight loss rate can be used as an important indicator to measure the preservation effect of asparagus. It can be seen from Table 4 that the weight loss rate of green asparagus treated with fresh-keeping under refrigeration increases slowly. At 30 days, the weight loss rate of the treatment group was less than 15%, while the weight loss rate of the untreated group was close to 25%, indicating that this fresh-keeping treatment can significantly reduce the weight loss rate of green asparagus.

Determination of vitamin C content

The content of vitamin C was determined by the 2,6-dichloroindophenol method. Accurately weigh 5g of the sample starting from the tip of the green asparagus and place it in a mortar, add an equal amount of 2% oxalic acid solution, grind it in the dark to form a slurry, transfer it to a 100mL volumetric flask, rinse with 1% oxalic acid solution, Pour into a volumetric flask, set the volume to the mark, shake well, and filter the solution for later use. Pour 10mL of the filtrate into a 100mL Erlenmeyer flask, and titrate the filtrate with the calibrated 2,6-dichloroindophenol solution. Stop the titration after the reddish color appears, and the color will not fade within 15s. Write down the dosage, and at the same time do blank titration with 10mL of 1% oxalic acid solution, and repeat the same method three times.

According to the amount of 2,6-dichloroindophenol, calculate the content of vitamin C in green asparagus, expressed by the quality of vitamin C contained in every 100g sample (fresh weight), ie mg/100g. The calculation formula is:

In the formula, V ₁ —the volume of dye used for titrating the sample extract, in mL;

V ₂ —the volume of dye consumed by blank titration, unit mL;

T— 1mL dye is equivalent to the quality of vitamin C, unit mg/mL;

m—the mass of the sample contained in the 10mL sample extract, in g.

Table 5 Changes of vitamin C content in asparagus

The content of vitamin C in asparagus is very rich, which can be used as an important indicator to evaluate the change of its storage quality. The changes of vitamin C in fresh-keeping treated and untreated asparagus under refrigerated conditions are shown in Table 5. With the prolongation of storage time, the vitamin C content of the fresh-keeping group and the control group showed a downward trend, but the vitamin C content of the fresh-keeping group decreased more slowly. It shows that the fresh-keeping treatment of this method can effectively reduce the vitamin C loss of green asparagus.

The content of chlorophyll was determined by spectrophotometer. Accurately weigh 1g of the sample from about 15cm below the tip of the green asparagus, put it into a mortar, add 5mL of pure acetone, grind it into a homogenate, then add 80% acetone and continue grinding until the tissue turns white, dilute to 25mL, darken Extract after 3~5min. Pour 5mL of the green clear solution into a large test tube, draw it up with a pipette, and shake it up for determination. 80% acetone was used as the blank control and the extract solution to read the optical density values at wavelengths of 663nm and 645nm, and repeated three times to obtain the average value. Calculate the total chlorophyll content, expressed as the mass of chlorophyll contained in every 100g sample (fresh weight), the unit is mg/100g, the calculation formula is as follows:

Ct＝ _20.2D645 ＋ _8.02D663

In the formula, D—the optical density value at a specific wavelength;

V—the final volume of chlorophyll extracted by acetone, unit mL;

m—the fresh weight of the sample, in g.

Table 6 Changes of chlorophyll content in asparagus

The green color of asparagus is an important sensory indicator. After harvesting, the chlorophyll on the skin of asparagus will gradually decompose, and the color will turn yellow. The decline trend of chlorophyll content of green asparagus stored at low temperature is shown in Table 6. The chlorophyll content of asparagus treated with fresh-keeping coating generally decreased slowly, which was significantly different from that of the control group. It can be seen that the treated asparagus has obvious advantages. The fresh-keeping coating treatment can delay the decomposition of chlorophyll, and can maintain the color of green asparagus for a long time.

Claims (9)

1. A composite preservative for fresh-cut fruits and vegetables, characterized in that: it comprises soaking liquid and spray gel solution; said soaking liquid is made of the following raw materials: low-viscosity chitosan, β-cyclodextrin, cinnamon essential oil, ascorbic acid , deionized water; the spray gel solution is made of the following raw materials: konjac glucomannan, carrageenan, and deionized water. 2. A kind of fresh-cut fruit and vegetable composite preservative according to claim 1, characterized in that: 0.5-1.5 parts of low-viscosity chitosan, 1.5-3 parts of β-cyclodextrin, cinnamon 0.5-2 parts of essential oil, 1-2.5 parts of ascorbic acid, and the rest are deionized water. 3. A kind of fresh-cut fruit and vegetable composite antistaling agent according to claim 1 or 2, characterized in that: the configuration method of the soaking liquid is as follows: add low-viscosity chitosan and β-cyclodextrin to deionized water and heat Stir to dissolve at 50-60°C, add cinnamon essential oil to seal, stir at 50-60°C for 2-6h, then add ascorbic acid to dissolve to obtain soaking solution. 4. A fresh-cut fruit and vegetable composite preservative according to claim 1 or 2, characterized in that: the viscosity of the low-viscosity chitosan in the soaking solution is 100-200 mPa ^. s. 5. A composite preservative for fresh-cut fruits and vegetables according to claim 1 or 2, characterized in that: the cinnamon essential oil in the soaking solution is extracted by steam distillation, and the cinnamaldehyde content is >65%. 6. A fresh-cut fruit and vegetable composite antistaling agent according to claim 1, characterized in that: the mass ratio of konjac glucomannan to carrageenan in the spray gel solution is 5.5:4.5. 7. A fresh-cut fruit and vegetable composite fresh-keeping agent according to claim 1 or 6, characterized in that: the pH value of the spray gel solution is 9-11. 8. the using method of a kind of fresh fruit and vegetable composite antistaling agent according to claim 1, is characterized in that: comprise the following steps: Soaking solution configuration: Add low-viscosity chitosan and β-cyclodextrin to deionized water and heat to 50-60°C and stir to dissolve, add cinnamon essential oil to seal, stir at 50-60°C for 2-6h, then add ascorbic acid to dissolve get soaking solution; Soaking: Soak the prepared fresh-cut fruits and vegetables in the soaking solution for 2-10 minutes, take them out, drain the water, and place them in a ventilated and dry place indoors to dry for 1-2 hours, so that the temperature drops to room temperature, and the surface is dry without obvious moisture; Spray film: Mix konjac glucomannan and carrageenan in proportion, add deionized water to adjust pH, heat to 80-90°C and stir to dissolve, make 2% mixed gel solution, cool to 60-80°C The gel solution is evenly sprayed onto the surface of soaked fruits and vegetables; Air-drying: The sprayed fruits and vegetables are air-dried at room temperature until there is no obvious moisture on the surface; Packaging: Packaging the processed fresh-cut fruits and vegetables, and then storing them. 9. The method of using a composite preservative for fresh fruits and vegetables according to claim 8, characterized in that: in step (5), the processed fresh-cut fruits and vegetables are packaged with PE plastic wrap or OPP ziplock bags, and then placed in 0-5 ℃ low temperature storage or normal temperature storage.