A food-grade multifunctional composite fruit preservative (solid beverage type) and its preparation method and application

Abstract

The application discloses a food-grade multifunctional composite fruit preservative (solid beverage type) and a preparation method and application thereof, and is characterized in that food-grade chitosan, vitamin C, citric acid, calcium chloride and potassium sorbate are optimally combined through specific proportioning and synergistic mechanism. The preservative can significantly and comprehensively inhibit the respiration, enzymatic browning, microbial infection and water softening of fruits, greatly reduces the water loss rate, mold rate, grain loss rate and fruit cracking rate of fruits, effectively delays the browning process of fresh-cut fruits, thereby greatly prolongs the shelf life of fruits and maintains the high-quality sensory characteristics. The application also provides a simple and efficient preparation method of the preservative and application of the preservative in fruit preservation. The preservative has a breakthrough synergistic preservation effect, high safety, convenient use and excellent cost-effectiveness.

Description

Technical Field

[0001] This invention belongs to the field of food science and engineering, particularly the field of postharvest preservation technology for agricultural products. Specifically, this invention relates to the components, formulation, preparation method, and application of a novel food-grade compound fruit preservative (solid beverage type) in extending the shelf life of fruits and maintaining their quality, while possessing both high safety and functionality. Background Technology

[0002] Fruits, as an important part of people's daily diet, are rich in vitamins, minerals, and dietary fiber, which are crucial to human health. However, after harvesting, fruits continue to undergo respiration and transpiration, and are susceptible to microbial contamination, leading to rapid mold growth, dehydration, oxidation, and a decline in sensory quality, severely shortening their shelf life and causing huge economic losses.

[0003] To address these issues, various fruit preservation technologies and products are currently available on the market. Common preservation methods include refrigeration, controlled atmosphere storage, and chemical preservative treatment. Chemical preservatives are widely used due to their ease of use and relatively low cost. However, traditional chemical preservatives, such as sodium benzoate and sulfur dioxide, while having some preservation effect, are increasingly attracting the attention of consumers and regulatory authorities regarding their safety, especially given today's rising awareness of food safety. People are demanding higher standards for the naturalness, non-toxicity, and residue-free properties of preservatives. Furthermore, many existing preservatives are in liquid form, resulting in high transportation costs, inconvenient storage, and susceptibility to spoilage.

[0004] To address these issues, various fruit preservation technologies and products are currently available on the market. Common preservation methods include refrigeration, controlled atmosphere storage, and chemical preservative treatment. Chemical preservatives are widely used due to their ease of use and relatively low cost. However, traditional chemical preservatives, such as sodium benzoate and sulfur dioxide, while having some preservation effect, are increasingly attracting the attention of consumers and regulatory authorities regarding their safety, especially given today's rising awareness of food safety. People are demanding higher standards for the naturalness, non-toxicity, and residue-free properties of preservatives. Furthermore, many existing preservatives are in liquid form, resulting in high transportation costs, inconvenient storage, and susceptibility to spoilage.

[0005] In recent years, preservatives based on natural or food-grade ingredients such as chitosan and vitamin C have gradually emerged. Chitosan, as a natural polysaccharide, has good film-forming properties, antibacterial properties, biocompatibility, and biodegradability; vitamin C is a highly effective antioxidant that can effectively inhibit enzymatic browning in fruits. However, the preservation effect of a single ingredient is often not comprehensive enough to cope with the complex deterioration mechanisms of fruits after harvest. Although compound preservatives have made up for the shortcomings of single ingredients to some extent, they still face challenges such as how to achieve synergistic effects among the components, how to ensure absolute safety and no residue in the product, and how to improve the ease of use of the product.

[0006] It is worth noting that tea polyphenols, as the main active ingredients in tea, possess significant antioxidant, antibacterial, and anti-inflammatory properties, among other biological activities. Green tea polyphenols, in particular, have garnered widespread attention due to their light color, strong antioxidant activity, and relatively mild bitterness. However, currently, there are few products that cleverly combine green tea polyphenols with food-grade ingredients such as chitosan and vitamin C, presenting them in a highly safe "solid beverage" form specifically for fruit preservation.

[0007] Therefore, developing a novel, efficient, safe, and convenient compound fruit preservative that can comprehensively extend the shelf life of fruits and maintain their excellent sensory characteristics, especially in the form of a "food-grade solid beverage" that is easily accepted by consumers, has important theoretical significance and broad market application prospects. Summary of the Invention

[0008] Purpose of the invention

[0009] The purpose of this invention is to provide a novel food-grade multifunctional compound fruit preservative. This preservative exists in the form of a water-soluble solid powder (solid beverage). Through scientific formulation and synergistic effect, it can comprehensively and effectively extend the shelf life of fruits and maintain their freshness. It also has the advantages of high safety, environmental friendliness, ease of use and cost-effectiveness.

[0010] Solution

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] In a first aspect of the present invention, a food-grade multifunctional composite fruit preservative is provided, characterized in that the preservative is a water-soluble solid powder (solid beverage) composed of the following components in weight percentage: chitosan 20%-30%, vitamin C 10%-15%, citric acid 10%-15%, calcium chloride 20%-30%, potassium sorbate 5%-8%, and green tea polyphenols 5%-10%.

[0013] Preferably, the food-grade multifunctional composite fruit preservative is composed of the following components by weight percentage: chitosan 25%, vitamin C 12%, citric acid 12%, calcium chloride 25%, potassium sorbate 6%, and green tea polyphenols 8%.

[0014] The second aspect of this invention provides a method for preparing a food-grade multifunctional composite fruit preservative, characterized by comprising the following steps: weighing the raw materials of each component according to the above weight percentage; mixing the raw materials of each component thoroughly until uniform; pulverizing and sieving the mixture to obtain fine solid powder; and packaging the obtained solid powder to obtain the food-grade multifunctional composite fruit preservative (solid beverage type) product of this invention.

[0015] Preferably, the above mixing process can be carried out in a mixer, and conventional pulverizing and sieving equipment can be used to ensure uniform powder fineness and easy dissolution.

[0016] The third aspect of the present invention provides a method for preserving fruit, the method comprising the following steps: dissolving the preservative in water to prepare a preservative solution, and then immersing the fruit in the preservative solution for treatment or spraying the preservative onto the surface of the fruit.

[0017] Preferably, the preservative solution is prepared by adding 2-3 grams of the food-grade multifunctional compound fruit preservative per liter of water and stirring until dissolved.

[0018] Preferably, the fruit is soaked for 5-15 minutes, then drained and air-dried or dried at low temperature.

[0019] Preferably, the fruits used for preservation include, but are not limited to, bunch tomatoes, apples, strawberries, grapes, cherries, citrus fruits, bananas, mangoes, etc.

[0020] Beneficial effects

[0021] Through extensive experimentation and screening, the inventors developed the fruit and vegetable preservative with the specific composition of this invention. Compared to existing technologies, the food-grade multifunctional composite fruit preservative of this invention has the following advantages:

[0022] (1) High safety and food-grade properties: All components used in this invention are food-grade raw materials, and the formula ratio has been optimized. At the recommended concentration, the diluted preservative solution meets the maximum usage requirements for solid beverages and related food additives in the national food safety standards, ensuring the safety of the treated fruit for consumption and eliminating consumers' concerns about chemical residues. The application as a "solid beverage" further emphasizes the safety and edibility of the product.

[0023] (2) Comprehensive and efficient synergistic preservation effect:

[0024] Chitosan: It forms a breathable selective membrane, inhibits respiration intensity, reduces water evaporation, and also has a broad-spectrum antibacterial effect, inhibiting microbial growth;

[0025] Vitamin C and green tea polyphenols: These two powerful natural antioxidants work synergistically to effectively scavenge free radicals, inhibit polyphenol oxidase activity, significantly delay fruit browning, and maintain the bright color of the pulp. The addition of green tea polyphenols further enhances antioxidant activity, and the lighter color does not affect the appearance of the fruit.

[0026] Citric acid: As an acidity regulator, it provides an acidic environment for chitosan dissolution and enhances the antibacterial activity of potassium sorbate. At the same time, it works synergistically with vitamin C and tea polyphenols to resist oxidation and gives the preservative liquid a fresh smell.

[0027] Calcium chloride: strengthens the cell wall structure of fruits, increases fruit firmness, reduces softening, and maintains crispness;

[0028] Potassium sorbate: As a highly effective and safe food preservative, it further inhibits the growth of mold and yeast.

[0029] The synergistic effect of the components comprehensively inhibits various deterioration conditions in fruits, such as rapid mold growth, dehydration, oxidation, and decline in sensory quality, thus significantly extending the shelf life of fruits.

[0030] (3) Ease of use: The product is in solid powder form, which is easy to store and transport and does not easily deteriorate. It can be easily dissolved in water and is suitable for farmers, wholesalers and household users.

[0031] (4) Environmental friendliness and economy: All raw materials used are biodegradable and environmentally friendly. Compared with traditional chemical preservatives, this invention provides an efficient and cost-effective preservation solution while ensuring safety.

[0032] (5) Broad-spectrum applicability: The preservative of this invention is applicable to a variety of fruits, including but not limited to bunch tomatoes, apples, strawberries, grapes, cherries, citrus, bananas, mangoes, etc., and has a good preservation effect on both whole fruits and fresh-cut fruits. Attached Figure Description

[0033] Figure 1 Trends in temperature and humidity in cold storage facilities.

[0034] Figure 2 Average water loss rate for each group at different storage times.

[0035] Figure 3 Mold growth rate for each group at different storage times.

[0036] Figure 4 The effect of preservatives on the preservation of tomatoes harvested in clusters after harvest.

[0037] Figure 5 The antioxidant effect of preservatives on fresh-cut apples. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0039] Furthermore, to better illustrate the present invention, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In some embodiments, materials, elements, methods, and means well known to those skilled in the art are not described in detail in order to highlight the spirit of the invention.

[0040] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0041] The present invention will be further described in detail below with reference to specific embodiments.

[0042] In the following examples, unless otherwise specified, all raw materials are commercially available products.

[0043] Example 1: Preparation of a food-grade multifunctional compound fruit preservative

[0044] Weigh the following raw materials by weight percentage:

[0045] Chitosan: 25kg;

[0046] Vitamin C: 12kg;

[0047] Citric acid: 12kg;

[0048] Calcium chloride: 25 kg;

[0049] Potassium sorbate: 6 kg;

[0050] Green tea polyphenols: 8kg.

[0051] Add the above raw materials to a mixer and mix thoroughly for 30 minutes to ensure uniform dispersion of each component. Grind the mixture using a pulverizer and then sieve it through a 200-mesh screen to obtain a fine, uniform solid powder. Package the obtained powder into individual 100-gram packets to obtain the food-grade multifunctional composite fruit preservative (solid beverage type) product of this invention.

[0052] Example 2: Preparation of Preservative Solution and Its Application in Preserving Cluster-Harvested Tomatoes

[0053] 1. Preparation of Preservative Solution

[0054] Take 100 grams of the food-grade multifunctional compound fruit preservative prepared in Example 1, add it to 50 liters of purified water, and stir until completely dissolved to obtain a transparent or slightly yellow preservative solution. At this point, the concentrations of each component in the preservative solution meet the maximum usage requirements for diluted solid beverage components in national food safety standards.

[0055] 2. Processing of tomatoes in clusters

[0056] Select Fuji bunches of tomatoes that are free of shed seeds, cracks, foreign objects, and mold. Soak them evenly in the prepared preservative solution for 5 minutes. After treatment, remove the bunches of tomatoes, drain excess water, and allow them to air dry naturally. Pack 18-20 bunches into each box and store them in a cold storage.

[0057] 3. Control group setup

[0058] Set up two control groups:

[0059] Control group A: Untreated bunch-harvested tomatoes.

[0060] Control group B: Tomatoes that were soaked in water for only 5 minutes.

[0061] 4. Storage conditions and effect evaluation

[0062] The clustered tomatoes in the treatment group and the control group were stored in a cold storage (15℃-17℃, relative humidity 80%-95%). On the 3rd, 6th and 8th days, the appearance was observed to check for mold, cracking, freshness of calyx, and loss of seeds, and photos were taken and recorded.

[0063] Water loss rate: Weigh and record the net weight on the first day of the experiment. Weigh and record the weight again on days 3, 6, and 8 of the experiment, and calculate the water loss rate as a percentage. The calculation formula is as follows:

[0064]

[0065] The formula for calculating the mold rate is as follows:

[0066]

[0067] The formula for calculating the pellet loss rate is as follows:

[0068]

[0069] 5. Results

[0070] During the experiment, the temperature in the cold storage remained relatively stable, generally between 16-17.5℃, and the humidity between 81%-88%. Figure 1 ).

[0071] Regarding water loss, such as Figure 2 As shown, the water loss rate in the experimental groups was relatively low, while the water loss rate in the control group A was faster, specifically reaching 2.65%. The water loss rate in the experimental groups was 14% lower than that in the control group A.

[0072] Table 1. Average water loss rate for different storage times in each group

[0073] Control group A Control group B experimental group 3 days 1.19% 0.78% 1.06% 6 days 1.88% 1.59% 1.73% 8 days 2.65% 1.84% 2.28%

[0074] Regarding mold, such as Figure 3 As shown, control groups A and B began to mold on the third day of cold storage, with the mold rate reaching a maximum of 15.00% on the eighth day. The experimental group had the lowest mold rate; no mold appeared on the third day of cold storage, and the mold rate increased to 0.47% on the eighth day, a 94% reduction compared to control group A. This demonstrates the significant anti-mold effect of the food-grade multifunctional compound fruit preservative.

[0075] Table 2. Mold growth rate of different groups at different storage times

[0076] Control group A Control group B experimental group 3 days 3.25% 5.00% 0.00% 6 days 6.10% 7.27% 0.47% 8 days 7.76% 15.00% 0.47%

[0077] Regarding grain shedding, no grain shedding was observed in any of the groups except for control group A. No grain shedding was observed on the 3rd and 6th days of storage. As the storage time was extended to the 8th day, the grain shedding rate was 5% (1 string of grains shed).

[0078] In terms of appearance, no condensation was observed at the bottom of any of the three groups. The results of water loss, mold, fruit drop, and fruit cracking are shown in Table 3. Based on the comprehensive results of all indicators, the food-grade multifunctional compound fruit preservative has a good preservation effect. Figure 4 ).

[0079] Table 3. Appearance changes of tomatoes harvested in each group

[0080] Control group A Control group B experimental group 3 days The sepals were slightly wilted, and some sepals showed signs of mold. The sepals were slightly wilted, and some sepals showed signs of mold. The sepals are fresh and show no signs of mold. 6 days The sepals curled up, and the amount of mold increased. The sepals showed slight wilting, mold growth increased, and fruit cracking occurred; the cracking rate was 0.28%. The sepals were slightly wilted, and some sepals showed signs of mold. 8 days The sepals are nearly dry, the amount of mold is increasing, and some are even shedding their seeds. The sepals withered, the amount of mold increased, and the degree of mold growth worsened. The sepals are nearly dry, and some sepals show signs of mold.

[0081] Example 3: Antioxidant effect of the food-grade multifunctional composite fruit preservative of the present invention on fresh-cut apples

[0082] 1. Test materials

[0083] Test preservative: The food-grade multifunctional composite fruit preservative prepared in Example 2.

[0084] Reference reagent: purified water (compliant with GB 5749 Standard for Drinking Water Quality).

[0085] Fruit tested: Fresh apples (Variety: Fuji), uniformly ripe, without mechanical damage, and free from pests and diseases.

[0086] Equipment: Clean fruit knife, small spray bottles (50 mL, 2), digital camera, constant temperature laboratory (temperature: 25±2℃, relative humidity: 60±5%).

[0087] 2. Test methods

[0088] Take the food-grade multifunctional composite fruit preservative prepared in Example 2 and fill it into a clean small spray bottle (marked as Bottle A); take an equal amount of purified water and fill it into a small spray bottle of the same size (marked as Bottle B) for later use.

[0089] Take one fresh apple, clean its surface, and then use a clean fruit knife to cut it in half lengthwise from the stem to the top of the apple, ensuring that the cut is flat.

[0090] Experimental group: Take half of an apple, place it horizontally with the cut side facing up, and spray the cut side evenly with bottle A (preservative). Press the nozzle twice to make the preservative evenly cover the entire cut surface and form a uniform liquid film.

[0091] Control group: The other half of the apple was placed in the same way, and bottle B (purified water) was used to spray the cut surface evenly. The nozzle was pressed twice to make the purified water evenly cover the cut surface.

[0092] 3. Observation and Recording

[0093] The test results are as follows Figure 5 As shown. 0h: At this time, the cut surfaces of both groups of apples were milky white with no significant difference, indicating freshness. 2h: The cut surfaces of the control group began to show slight browning, while the cut surfaces of the experimental group remained milky white with no significant change. 3h: The browning of the control group's cut surfaces deepened significantly, turning light brown; the cut surfaces of the experimental group only showed slight discoloration, with a significantly better color than the control group. 5h: The cut surfaces of the control group showed severe browning, turning dark brown; although the cut surfaces of the experimental group showed slight browning, the color was significantly lighter than that of the control group, indicating a significant preservation effect.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A food-grade multifunctional compound fruit preservative, characterized in that, The preservative is a water-soluble solid powder composed of the following components by weight percentage: chitosan 20% - 30%, vitamin C 10% - 15%, citric acid 10% - 15%, calcium chloride 20% - 30%, potassium sorbate 5% - 8%, and green tea polyphenols 5% - 10%.

2. The food-grade multifunctional composite fruit preservative according to claim 1 or 2, characterized in that, The degree of deacetylation of the chitosan is above 85%, and the molecular weight ranges from 50 to 500 kDa.

3. The food-grade multifunctional composite fruit preservative according to claim 1 or 2, characterized in that, The purity of the green tea polyphenols is above 90%, of which the catechin content is not less than 70%.

4. The compound fruit preservative according to claim 1 or 2, characterized in that, The vitamin C mentioned is food-grade L-ascorbic acid with a purity greater than 99%.

5. A method for preparing a food-grade multifunctional composite fruit preservative, characterized in that, Includes the following steps: (1) Weigh out each component raw material as described in claim 1 or 2; (2) Mix all the raw materials thoroughly until homogeneous; (3) The mixture is crushed and sieved to obtain fine solid powder; (4) The obtained solid powder is packaged to obtain the food-grade multifunctional composite fruit preservative product of the present invention.

6. The preparation method according to claim 5, characterized in that, The mixing process is carried out in a mixer, and the pulverization and sieving are carried out using conventional pulverization and sieving equipment to ensure uniform powder fineness and easy dissolution.

7. The application of the food-grade multifunctional composite fruit preservative as described in claim 1 or 2 in fruit preservation, characterized in that, The preservative is dissolved in water to prepare a preservative solution, and then the fruit is soaked in the preservative solution for treatment.

8. The application according to claim 7, characterized in that, The preparation method of the preservation liquid is as follows: add 2-3 grams of the food-grade multifunctional compound fruit preservative per liter of water and stir until dissolved.

9. The application according to claim 7 or 8, characterized in that, The fruit is soaked for 5-15 minutes, then drained and air-dried or dried at low temperature.

10. The application according to claim 7 or 8, characterized in that, The fruits include, but are not limited to, bunch tomatoes, apples, strawberries, grapes, cherries, citrus fruits, bananas, mangoes, etc.

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