Fruit and vegetable anti-browning agent and method for delaying browning of fresh-cut fruits and vegetables

Abstract

The invention discloses a fruit and vegetable anti-browning agent and a method for delaying browning of fresh-cut fruits and vegetables, and belongs to the technical field of fruit and vegetable food processing. The fruit and vegetable anti-browning agent comprises a sodium alginate solution and a mixture of calcium carbonate and glucose oxidase, and the sodium alginate solution and the mixture are separately and independently packaged. The surfaces of fresh-cut fruits and vegetables are subjected to film coating treatment based on the fruit and vegetable anti-browning agent, so that the respiration of pulp is reduced, the enzymatic browning effect is reduced, and the purpose of delaying pulp browning is achieved. Besides, due to the fact that the method is free of pollution, safe and non-toxic, and formation of the calcium alginate hydrogel induced by glucose oxidase is applied, the method can be expanded and used in production requirements of various fresh-cut fruits and vegetables or fruit and vegetable storage, a coating outer surface layer with good gelling property is developed, and an effective solution is provided for delaying browning of fruit and vegetable products.

Description

Technical Field

[0001] The invention relates to a fruit and vegetable anti-browning agent and a method for delaying the browning of fresh-cut fruits and vegetables, belonging to the technical field of fruit and vegetable food processing. Background Art

[0002] Fresh-cut fruits are loved by consumers for their freshness, convenience and nutrition. In particular, the street drinks that have emerged in recent years have placed great demand on fresh-cut fruits. Since fresh-cut fruits may be mechanically damaged during processing, leading to loss of nutrients and microbial infection, the preservation technology of fresh-cut fruits has important practical significance.

[0003] Many preservation technologies have been studied for different fresh-cut fruits and application scenarios, and a small number of application explorations have also been carried out, such as high-pressure processing, ultrasound, pulsed electric field and magnetic field and other non-thermal physical technologies, low-temperature storage technology, modified atmosphere packaging technology, edible coating technology, nano packaging technology, etc. However, due to factors such as equipment investment, safety and applicability of preservation materials, and complexity of preservation processing, there are still relatively few actual applications.

[0004] Existing studies have reported that fresh-cut pineapples can be treated with 1% ascorbic acid to significantly slow down the browning of the flesh; fresh-cut melons can be wrapped in a double layer of degradable plastic wrap to slow down the loss of vitamin C, maintain the activity of the SOD enzyme, and have a preservation effect; the combined treatment of nano zinc oxide coating (0.7 g / L) and pressurized argon (2 MPa, 30 min) can effectively reduce the mass loss of fresh-cut oranges, reduce the increase in soluble solids, slow down the decrease in titratable acid and ascorbic acid content, and have a preservation effect.

[0005] As a respiratory climacteric fruit, peaches still have strong respiration at room temperature after harvesting, and they quickly ripen and soften. They are easily damaged mechanically during transportation, and rot and deteriorate due to the combined action of surface microorganisms and endogenous enzymes. Therefore, they are often eaten directly as fresh fruits. In order to make better use of peach pulp resources, the development of fresh-cut peach products has become one of the solutions to expand fresh peach consumption. At present, peach juice is the main direction of peach processing products. The browning of peach pulp during the processing and storage of mixed peach pulp juice is one of the technical problems that need to be solved urgently. The browning of fresh-cut peach pulp is mainly enzymatic browning. Endogenous enzymes such as polyphenol oxidase (PPO) and peroxidase (POD) use phenolic substances in the pulp tissue as natural substrates, and catalyze oxidation with the participation of active oxygen to generate quinone substances, which further polymerize to form browning products, thereby causing the fresh-cut peach pulp to brown rapidly, affecting the flavor and appearance of peach products, increasing production costs, and causing obstacles to peach processing, storage and sales.

[0006] The existing peach preservation technologies mainly include controlled atmosphere storage, low temperature preservation, microbial antagonistic preservation and composite preservatives, all of which have a certain effect on delaying the browning of peach fruits. However, for fresh-cut peaches, these technologies cannot be directly introduced. For example, controlled atmosphere preservation is not effective for cut peaches, low temperature storage is prone to chilling damage, and environmental conditions often change during application, resulting in loss of aromatic substances and blackening of color. The coating preservation method has been widely used in fruit and vegetable preservation due to its simple method and low cost. Among them, sodium alginate has attracted much attention in the field of composite film preparation as a safe coating material. It is a polysaccharide compound extracted from natural products such as kelp or fungi, which is non-toxic and pollution-free, has good antibacterial and film-forming properties, and has good flexibility after film formation. However, as a hydrophilic substrate, sodium alginate coating is easily eroded by water, and in different peach product production and storage environments, single-component coating materials are often difficult to meet the complex peach preservation requirements. For fresh-cut peaches used in the field of tea drinks, the coating process is also relatively complicated and the application convenience is not good.

[0007] Therefore, based on the rapid browning and quality degradation problems faced by fresh-cut peaches during use, it is urgent to propose a preservation method that can better maintain the quality of peach flesh under refrigeration and room temperature conditions. Summary of the invention

[0008] [Technical issues]

[0009] Fresh-cut fruits and vegetables are prone to rapid browning and quality degradation when used, which affects the flavor and appearance of fruit and vegetable products, increases production costs, and creates obstacles to fruit and vegetable processing, storage, and sales.

[0010] [Technical solution]

[0011] To solve the above problems, the purpose of the present invention is to use glucose oxidase (GOx) to specifically catalyze glucose oxidation to produce an oxidation product, gluconic acid, which acts on ultrafine powdered calcium carbonate to dissolve calcium ions. The released calcium ions then promote the gelation of the sodium alginate solution in the system, and the formed calcium alginate hydrogel is wrapped around the fresh-cut fruits and vegetables to achieve the effect of anti-oxidation and enhanced preservation. At the same time, the glucose oxidation reaction catalyzed by GOx can consume oxygen in the microenvironment and reduce pH, both of which have a certain inhibitory effect on enzyme activity, providing support for delaying the browning of fresh-cut fruits and vegetables at room temperature or refrigerated conditions.

[0012] In order to achieve the above purpose, the technical solutions provided are as follows:

[0013] The invention provides a fruit and vegetable anti-browning agent, comprising a sodium alginate solution, a mixture of calcium carbonate and glucose oxidase, wherein the sodium alginate solution and the mixture are separately packaged.

[0014] In one embodiment, the concentration of the sodium alginate solution is 0.1-1%, g / ml.

[0015] In one embodiment, the mass ratio of calcium carbonate to glucose oxidase is 4:1 to 1:1 to 2.

[0016] In one embodiment, the enzyme activity of the glucose oxidase is 10000-13000 GODU / g.

[0017] In one embodiment, when the fruit and vegetable anti-browning agent is used, a mixture of calcium carbonate and glucose oxidase is first dissolved in water to form a suspension; then the fruits and vegetables to be preserved are placed in a sodium alginate solution, and the suspension is added and mixed evenly.

[0018] The present invention also provides a method for delaying browning of fresh-cut fruits and vegetables based on calcium alginate gel mediated by glucose oxidase, the method comprising the following steps:

[0019] (1) adding sodium alginate into water and fully dissolving it to obtain a sodium alginate solution;

[0020] (2) premixing calcium carbonate and glucose oxidase, and then adding them into water and stirring to prepare a suspension;

[0021] (3) placing fresh-cut fruits and vegetables in the sodium alginate solution of step (1), adding the suspension of step (2), stirring for reaction, and refrigerating.

[0022] In one embodiment, the preparation process of the sodium alginate solution in step (1) is specifically as follows: dispersing sodium alginate in water, placing in a water bath and stirring until the sodium alginate is completely dissolved into a uniform and stable solution, and refrigerating in a refrigerator at 4° C. to obtain the sodium alginate solution.

[0023] In one embodiment, the preparation of the suspension in step (2) is specifically to add the pre-mixed calcium carbonate and glucose oxidase powder into water, place the mixture in a water bath at 45-50° C. and stir to obtain the suspension.

[0024] In one embodiment, the amount of calcium carbonate added to the suspension is 0.5-2.0 wt % (relative to fresh-cut fruits and vegetables); the concentration of glucose oxidase is 0.5-2.0 wt % (relative to fresh-cut fruits and vegetables).

[0025] In one embodiment, the calcium carbonate is food-grade light calcium carbonate, which meets the requirements of national standard 1886.214 and has a mesh size of 200 or more.

[0026] In one embodiment, the stirring reaction conditions in step (2) are: the temperature is 40-60° C. and the reaction is left open.

[0027] In one embodiment, the refrigeration in step (2) is storage at 2-10°C.

[0028] In one embodiment, the fresh-cut fruits and vegetables in step (2) are one or more of peaches, bananas, apples, melons and fruits and their derivatives.

[0029] The present invention also provides application of the above method in the production and processing of fruit and vegetable products.

[0030] [Beneficial Effects]

[0031] (1) The present invention proposes to form a calcium alginate hydrogel system induced by glucose oxidase, which has the characteristics of being soft, good coating, and slowing down the contact of oxygen with the coated object, so that the browning rate of fresh-cut peach pulp at room temperature exposed to air is slowed down, thereby producing more stable peach pulp processed products;

[0032] (2) Glucose oxidase acts on glucose to produce gluconic acid, which then reacts with calcium carbonate to dissolve calcium ions, making the application more controllable. In particular, the catalytic reaction consumes oxygen in the microenvironment and significantly slows down the respiration of the pulp, further reducing oxidative browning. Gluconic acid, as a mild acidulant, reacts with sodium alginate to form a hydrogel, which lowers the pH of the system and basically maintains it above pH 2.0. In addition, the texture of calcium alginate hydrogel is weak and will not affect the taste of the food system. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The diagram shows the appearance changes of peach flesh obtained in Examples 1-7 and Comparative Examples 1-2 (0 and 6h). DETAILED DESCRIPTION

[0034] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0035] The test and characterization methods involved in the embodiments and comparative examples of the present invention are as follows:

[0036] (1) Determination of peach flesh brightness value

[0037] Peach flesh was randomly selected and placed in a transparent plastic cup. Five groups of parallel samples were measured using a colorimeter (Konica Minolta CR-10) and the L* average was taken.

[0038] (2) Specific Examples and Control Groups

[0039] To facilitate the implementation of the operation, the dosage of the following material components is expressed as follows: ultrafine calcium carbonate powder is purchased from the food additive light calcium carbonate produced by Jiangxi Mingyuan High-tech Materials Co., Ltd.; glucose oxidase powder is purchased from the powdered glucose oxidase product provided by Novozymes (China) Investment Co., Ltd., with an enzyme activity of 13000GODU / g, all calculated in g / g peach flesh.

[0040] Example 1 0.25% sodium alginate solution + 1% calcium carbonate + 1% glucose oxidase

[0041] A method for delaying browning of fresh-cut peach flesh based on calcium alginate gel mediated by glucose oxidase, comprising the following steps:

[0042] (1) Add 1.25 g of sodium alginate powder to 500 mL of water, place in a 60°C water bath and stir to form a stable sodium alginate solution, referred to as solution A, which is then placed in a refrigerator for refrigeration;

[0043] (2) Premix 1 g of ultrafine calcium carbonate powder and 1 g of glucose oxidase powder, add to 25 mL of water, place in a 50°C water bath and stir to prepare a suspension, which is referred to as solution B;

[0044] (3) Weigh 100 g of peach chunks and place them in liquid A. Add liquid B while stirring. Continue stirring for 5 min. Allow to react at room temperature for 15 min. Place the mixture in a refrigerator at 4°C and refrigerate.

[0045] In this example, the peach flesh was scooped out with a colander after 30 minutes and placed in a colorimeter to measure the brightness value, L* being 73.2. The peach flesh was returned to the original system and placed at 15°C for 6 hours before being photographed again and the brightness value was measured, L* being 58.7.

[0046] Example 2 0.1% sodium alginate solution + 1% calcium carbonate + 1% glucose oxidase

[0047] A method for delaying browning of fresh-cut peach flesh based on calcium alginate gel mediated by glucose oxidase, comprising the following steps:

[0048] (1) Add 1 g of sodium alginate powder to 1 L of water, place in a 60°C water bath and stir to form a stable sodium alginate solution, referred to as solution A, which is then placed in a refrigerator;

[0049] (2) Premix 1 g of ultrafine calcium carbonate powder and 1 g of glucose oxidase powder, add to 25 mL of water, place in a 50°C water bath and stir to prepare a suspension, which is referred to as solution B;

[0050] (2) Weigh 100 g of peach chunks and place them in liquid A. Add liquid B while stirring. Continue stirring for 5 min. Allow to react at room temperature for 20 min. Place the mixture in a refrigerator at 4°C and refrigerate.

[0051] In this example, the peach flesh was scooped out with a colander after 30 minutes and placed in a colorimeter to measure the brightness value, L* being 69.6. The peach flesh was returned to the original system and placed at 15°C for 6 hours before being photographed again and the brightness value was measured, L* being 52.8.

[0052] Example 3 0.5% sodium alginate solution + 1% calcium carbonate + 2% glucose oxidase

[0053] A method for delaying browning of fresh-cut peach flesh based on calcium alginate gel mediated by glucose oxidase, comprising the following steps:

[0054] (1) Add 5 g of sodium alginate powder to 1 L of water, place in a 60°C water bath and stir to form a stable sodium alginate solution, referred to as solution A, which is then placed in a refrigerator for refrigeration;

[0055] (2) Premix 1 g of ultrafine calcium carbonate powder and 2 g of glucose oxidase powder, add to 30 mL of water, place in a 50°C water bath and stir to prepare a suspension, which is referred to as solution B;

[0056] (3) Weigh 100 g of peach chunks and place them in liquid A. Add liquid B while stirring. Continue stirring for 5 min. Allow to react at room temperature for 15 min. Place the mixture in a refrigerator at 4°C and refrigerate.

[0057] In this example, the peach flesh was scooped out with a colander after 30 minutes, and the brightness value was measured in a colorimeter, and the L* was 66.5. The peach flesh was returned to the original system, and after being placed at 15° C. for 6 hours, the peach flesh was photographed again and the brightness value was measured, and the L* was 50.5.

[0058] Example 4 1% sodium alginate solution + 2% calcium carbonate + 2% glucose oxidase

[0059] A method for delaying browning of fresh-cut peach flesh based on calcium alginate gel mediated by glucose oxidase, comprising the following steps:

[0060] (1) Add 10.0 g of sodium alginate to 1 L of deionized water, place in a 60°C water bath and stir to form a stable sodium alginate solution, which is referred to as solution A.

[0061] (2) Premix 2 g of ultrafine calcium carbonate powder and 2 g of glucose oxidase powder, disperse in 20 mL of water, place in a 50°C water bath and stir to prepare a suspension, which is referred to as solution B;

[0062] (3) Take out liquid A and cool it at room temperature, add 100 g of the prepared peach pieces, add liquid B while stirring, continue stirring for 5 minutes, react at room temperature for 15 minutes, and place in a refrigerator at 4°C for refrigeration.

[0063] In this example, peach flesh was fished out after 30 minutes, and the brightness value was measured in a colorimeter, and L* was 72.8. The peach flesh was returned to the original system, and after being placed at 15° C. for 6 hours, the peach flesh was photographed again and the brightness value was measured, and L* was 70.6.

[0064] Example 5 0.5% sodium alginate solution + 0.5% calcium carbonate + 2% glucose oxidase

[0065] A method for delaying browning of fresh-cut peach flesh based on calcium alginate gel mediated by glucose oxidase, comprising the following steps:

[0066] (1) Add 2.5 g of sodium alginate powder to 500 mL of water, place in a 60°C water bath and stir to form a stable sodium alginate solution, referred to as solution A, which is then placed in a refrigerator for refrigeration;

[0067] (2) Premix 0.5 g of ultrafine calcium carbonate powder and 2 g of glucose oxidase powder, add to 30 mL of water, place in a 50°C water bath and stir to prepare a suspension, which is referred to as solution B;

[0068] (3) Weigh 100 g of peach chunks and place them in liquid A. Add liquid B while stirring. Continue stirring for 5 min. Allow to react at room temperature for 10 min. Place the mixture in a refrigerator at 4°C and store.

[0069] In this example, the peach flesh was scooped out with a colander after 30 minutes and placed in a colorimeter to measure the brightness value, L* being 67.8. The peach flesh was returned to the original system and placed at 15°C for 6 hours before being photographed again and the brightness value was measured, L* being 48.6.

[0070] Example 6 0.1% sodium alginate solution + 1% calcium carbonate + 2% glucose oxidase

[0071] A method for delaying browning of fresh-cut peach flesh based on calcium alginate gel mediated by glucose oxidase, comprising the following steps:

[0072] (1) Add 1.0 g of sodium alginate powder to 1 L of water, place in a 60°C water bath and stir to form a stable sodium alginate solution, referred to as solution A, which is then placed in a refrigerator for refrigeration;

[0073] (2) Premix 1.0 g of ultrafine calcium carbonate powder and 2 g of glucose oxidase powder, add to 20 mL of water, place in a 50°C water bath and stir to prepare a suspension, which is referred to as solution B;

[0074] (3) Weigh 100 g of peach chunks and place them in liquid A. Add liquid B while stirring. Continue stirring for 5 min. Allow the mixture to react at room temperature for 10 min. Place the mixture in a refrigerator at 4°C and refrigerate.

[0075] In this example, the peach flesh was scooped out with a colander after 30 minutes and placed in a colorimeter to measure the brightness value, L* being 69.6. The peach flesh was returned to the original system and placed at 15°C for 6 hours before being photographed again and the brightness value was measured, L* being 47.9.

[0076] Example 7 0.1% sodium alginate solution + 1% calcium carbonate + 0.5% glucose oxidase

[0077] A method for delaying browning of fresh-cut peach flesh based on calcium alginate gel mediated by glucose oxidase, comprising the following steps:

[0078] (1) Add 0.5 g of sodium alginate powder to 500 mL of water, place in a 60°C water bath and stir to form a stable sodium alginate solution, referred to as solution A, which is then placed in a refrigerator for refrigeration;

[0079] (2) Premix 1.0 g of ultrafine calcium carbonate powder and 0.5 g of glucose oxidase powder, add to 20 mL of water, place in a 50°C water bath and stir to prepare a suspension, which is referred to as solution B;

[0080] (3) Weigh 100 g of peach chunks and place them in liquid A. Add liquid B while stirring. Continue stirring for 5 min. Allow to react at room temperature for 30 min. Place the mixture in a refrigerator at 4°C and store.

[0081] In this example, the peach flesh was scooped out with a colander after 30 minutes and placed in a colorimeter to measure the brightness value, L* being 68.2. The peach flesh was returned to the original system and placed at 15°C for 6 hours before being photographed again and the brightness value was measured, L* being 49.1.

[0082] Comparative Example 1

[0083] Weigh 100 g of peach pieces and place them in 500 mL of vitamin C aqueous solution. Stir continuously for 5 minutes and then refrigerate in a 4°C refrigerator.

[0084] In this comparative example, the peach flesh was scooped out with a colander after 30 minutes and placed in a colorimeter to measure the brightness value, L* being 48.7. The peach flesh was returned to the original system and placed at 15°C for 6 hours before being photographed again and the brightness value was measured, L* being 42.1.

[0085] Comparative Example 2: Add 0.1% gluconic acid

[0086] (1) 0.5 g of sodium alginate powder was added to 500 mL of water, and the mixture was placed in a 60° C. water bath and stirred to form a stable sodium alginate solution. 1.0 g of ultrafine calcium carbonate powder was added thereto and stirred evenly to obtain a mixed solution, which was recorded as solution A.

[0087] (2) Add 0.5 g of gluconic acid to 20 mL of water, place in a 50°C water bath and stir to prepare a solution, which is referred to as Solution B.

[0088] (3) Weigh 100 g of peach chunks and place them in liquid A. Add liquid B while stirring. Continue stirring for 5 min. Allow to react at room temperature for 15 min. Place the mixture in a refrigerator at 4°C and refrigerate.

[0089] In this comparative example, peach flesh was scooped out with a colander after 30 minutes and placed in a colorimeter to measure the brightness value, L* being 47.2. The peach flesh was returned to the original system and placed at 15°C for 6 hours before being photographed again and the brightness value was measured, L* being 41.6.

[0090] Results Analysis

[0091] The brightness values ​​of the fresh-cut peach flesh of Examples 1 to 7 and Comparative Examples 1 to 2 were measured, and the results are shown in Table 1:

[0092] Table 1 Brightness values ​​of fresh-cut peach flesh

[0093]

[0094] From the results in Table 1, it can be seen that within the range of sodium alginate concentration of 0.1-1.0%, (g / ml), the strength of the formed hydrogel is appropriate and more suitable for application requirements. The amount of calcium carbonate used is about 1% (g / g, for peach meat) to meet the needs of neutralizing gluconic acid and forming a hydrogel. Usually, the addition amount of glucose oxidase is high, and the speed of converting glucose into gluconic acid is faster, and a higher amount of calcium carbonate is required to neutralize it, which is conducive to the timely progress of the enzyme reaction and the rapid formation of the hydrogel. The amount of glucose oxidase powder used is about 1% (g / g, for peach meat), and can be adjusted to no more than 2% according to the actual system.

Claims

1. A fruit and vegetable anti-browning agent, characterized in that: The invention comprises a sodium alginate solution, a mixture of calcium carbonate and glucose oxidase, wherein the sodium alginate solution and the mixture are packaged separately and independently.

2. The anti-browning agent for fruits and vegetables according to claim 1, characterized in that The concentration of the sodium alginate solution is 0.1-1%, g / ml.

3. The anti-browning agent for fruits and vegetables according to claim 1, characterized in that The mass ratio of the calcium carbonate to the glucose oxidase is 4:1 to 1:1 to 2.

4. The anti-browning agent for fruits and vegetables according to claim 1, characterized in that The enzyme activity of the glucose oxidase is 10000-13000 GODU / g.

5. The anti-browning agent for fruits and vegetables according to claim 1, characterized in that: When the fruit and vegetable anti-browning agent is used, the mixture of calcium carbonate and glucose oxidase is first dissolved in water to form a suspension; then the fruits and vegetables to be preserved are placed in a sodium alginate solution, and the suspension is added and mixed evenly.

6. A method for delaying browning of fresh-cut fruits and vegetables based on glucose oxidase-mediated calcium alginate gel, characterized in that: The method comprises the following steps: (1) adding sodium alginate into water and fully dissolving it to obtain a sodium alginate solution; (2) premixing calcium carbonate and glucose oxidase, and then adding them into water and stirring to prepare a suspension; (3) placing fresh-cut fruits and vegetables in the sodium alginate solution of step (1), adding the suspension of step (2), stirring for reaction, and refrigerating.

7. The method according to claim 6, characterized in that The preparation of the suspension in step (2) is specifically to add the pre-mixed calcium carbonate and glucose oxidase powder into water, place the mixture in a water bath at 45-50° C. and stir to obtain a suspension.

8. The method according to claim 6, characterized in that The amount of calcium carbonate added to the suspension is 0.5-2.0 wt% relative to the mass of fresh-cut fruits and vegetables; the amount of glucose oxidase added is 0.5-2.0 wt% relative to the mass of fresh-cut fruits and vegetables.

9. The method according to claim 6, characterized in that The fresh-cut fruits and vegetables in step (2) are one or more of peaches, bananas, apples, melons and fruits and their derivatives.

10. Use of the method according to any one of claims 6 to 9 and the anti-browning agent for fruits and vegetables according to any one of claims 1 to 5 in the production and processing of fruit and vegetable products.

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