CN110057609B - Reference sample for testing preservation effect and preparation method and application thereof - Google Patents

Abstract

The invention belongs to the technical field of preservation performance detection, and particularly relates to a reference sample for preservation effect testing, and a preparation method and application thereof. The reference sample for the preservation effect test comprises a water absorbing material, and the water absorbing material absorbs mixed liquid of chlorophyll, a humectant and an antioxidant. The consistency among reference samples is good, the method can be widely applied to the fresh-keeping effect evaluation of refrigerators and freezers, the experimental error is small, the repeatability is good, and good comparison work can be performed among different laboratories.

Description

A reference sample for fresh-keeping effect test and preparation method and application thereof

technical field

The invention relates to the technical field of fresh-keeping performance detection, in particular to a reference sample for fresh-keeping effect testing and a preparation method and application thereof.

Background technique

The refrigerator is the first choice for food preservation in our daily life. In order to meet consumers' demand for fresh-keeping, various refrigerator manufacturers are constantly upgrading the fresh-keeping ability of the storage space of refrigerators. At present, the evaluation of the preservation effect of refrigerators mainly uses fresh vegetables such as spinach to be stored in the refrigerator for a certain period of time (such as 3 or 4 days) to detect the moisture, vitamin C, vitamin E, chlorophyll, vitamin B family, folic acid, etc. The changes of the indicators are evaluated by analyzing the maintenance of each indicator by each refrigerator to evaluate the preservation effect.

At present, the method of using fresh vegetables as the storage object to evaluate the effect of preservation has the following shortcomings: First, it is greatly affected by the harvesting season of vegetables, and the supply of the vegetables in non-seasonal seasons is difficult to effectively guarantee; second, the uniformity of fresh vegetables, product quality The stability of traits is difficult to guarantee. These shortcomings easily lead to large experimental errors and poor repeatability, making it difficult to carry out good comparisons between different laboratories.

In view of this, the present invention is proposed.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a reference sample for fresh-keeping effect test. In order to solve the method for evaluating fresh-keeping effect by using fresh vegetables as storage objects in the prior art, one is that it is greatly affected by the harvesting season of vegetables, and the It is difficult to effectively guarantee the supply of the vegetables in seasonal seasons. Second, the uniformity of fresh vegetables and the stability of product characteristics are difficult to guarantee, resulting in large experimental errors and poor repeatability, making it difficult to carry out good comparisons between different laboratories. . The reference sample for the fresh-keeping effect test includes a water-absorbing material, and the water-absorbing material absorbs a mixed solution of chlorophyll, a moisturizing agent and an antioxidant. The consistency between the reference samples is good, and it can be widely used in the evaluation of the preservation effect of refrigerators. The experimental error is small, and the repeatability is good. It can carry out good comparison work between different laboratories.

Another object of the present invention is to provide the above-mentioned preparation method of the reference sample for fresh-keeping effect test, contact the water-absorbing material, chlorophyll, humectant and antioxidant in a liquid environment, the process is simple, the production efficiency is high, and the reference sample sample The consistency between them is good, and it can be widely used in the evaluation of the preservation effect of refrigerators and freezers, and the inter-laboratory ability comparison of refrigerator and freezer preservation evaluation tests, etc., and has broad application prospects.

Another object of the present invention is to provide the application of the above-mentioned reference sample for fresh-keeping effect test in detecting the fresh-keeping effect of refrigerators and/or freezers.

A reference sample for fresh-keeping effect test includes a water-absorbing material, and the water-absorbing material absorbs a mixed solution of chlorophyll, a moisturizing agent and an antioxidant.

Preferably, the water-absorbing material is packed in a breathable water-proof bag;

Preferably, the size of the air-permeable water barrier is 5-10cm×8-15cm, more preferably 6-8cm×10-12cm.

Preferably, the water-absorbing material is multi-layered, and each layer or several layers are separated by a waterproof material;

Preferably, the water-absorbing material is stacked together by 5-10 pieces;

Preferably, the size of each layer of the water-absorbing material is the same or different;

Preferably, the size of the water-absorbing material is 3-8cm×6-13cm, more preferably 4-6cm×8-10cm.

Preferably, the water-absorbing material is selected from at least one of non-woven fabrics, cotton fabrics or polyester fabrics;

Preferably, the waterproof material is selected from at least one of PP film, PE film or PET film.

Preferably, the antioxidant is selected from at least one of L-ascorbic acid, butylated hydroxyanisole, dibutylated hydroxytoluene and propyl gallate.

Preferably, the humectant is selected from at least one of propylene glycol, glycerol and sorbitol.

Preferably, the mass ratio of the antioxidant and the chlorophyll is 9-12:1, more preferably 10-11:1.

Preferably, the solvent of the mixed solution is water;

Preferably, the water is deoxygenated water, and a non-oxidizing protective gas is dissolved;

Preferably, the non-oxidizing protective gas is nitrogen.

The preparation method of the reference sample for the fresh-keeping effect test as above, comprises the following steps:

contacting the water-absorbing material, chlorophyll, humectant and antioxidant in a liquid environment;

Preferably, the contact time is 4-8 min, more preferably 5-6 min.

The application of the above-mentioned reference sample for fresh-keeping effect test in detecting the fresh-keeping effect of refrigerator and/or freezer.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The consistency between the reference samples for the fresh-keeping effect test in the present invention is good, and it can be widely used in the evaluation of the fresh-keeping effect of refrigerators. The experimental error is small, and the repeatability is good. comparison work.

(2) The preparation method of the reference sample for the fresh-keeping effect test in the present invention, the water-absorbing material, chlorophyll, humectant and antioxidant are contacted in a liquid environment, and a film with better water-permeability and air permeability is used as an outer package to make a reference sample. The preparation process is simple, the production efficiency is high, and the consistency between the reference samples is good, can be widely used in the evaluation of the preservation effect of refrigerators and freezers, and has wide application prospects.

Description of drawings

In order to illustrate the specific embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the specific embodiments or the prior art. Obviously, the accompanying drawings in the following description The drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

Fig. 1 is the preparation process flow chart of the reference sample for the preservation effect test in the present invention.

Detailed ways

The embodiments of the present invention will be described in detail below with reference to the examples, but those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. If the specific conditions are not indicated in the examples, it is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used without the manufacturer's indication are conventional products that can be purchased from the market.

A reference sample for fresh-keeping effect test includes a water-absorbing material, and the water-absorbing material absorbs a mixed solution of chlorophyll, a moisturizing agent and an antioxidant.

The reference sample for the fresh-keeping effect test in the present invention has good consistency among the samples, and can be widely used in the evaluation of the fresh-keeping effect of refrigerators and freezers.

Preferably, the water-absorbing material is packed in a breathable water-proof bag;

Preferably, the size of the air-permeable water barrier is 5-10cm×8-15cm, more preferably 6-8cm×10-12cm.

Typical but non-limiting dimensions of the breathable water barrier are, for example, 5 cm x 8 cm, 6 cm x 9 cm, 7 m x 10 cm, 8 cm x 11 cm, 9 cm x 12 cm or 10 cm x 15 cm.

Preferably, the water-absorbing material is multi-layered, and each layer or several layers are separated by a waterproof material;

Preferably, the water-absorbing material is stacked together by 5-10 pieces;

Preferably, the size of each layer of the water-absorbing material is the same or different;

Stacking multiple layers of water-absorbing materials together, each layer of water-absorbing material is separated by a waterproof material, can ensure the consistency between reference samples and make it more accurate when used to evaluate the preservation effect of refrigerators or freezers, and the experimental error is small , and the repeatability is good.

Preferably, the size of the water-absorbing material is 3-8cm×6-13cm, more preferably 4-6cm×8-10cm.

Typical but non-limiting dimensions of the water-absorbing material are, for example, 3 cm x 6 cm, 4 cm x 7 cm, 5 cm x 8 cm, 6 cm x 9 cm, 7 cm x 10 cm or 8 cm x 13 cm.

Preferably, the water-absorbing material is selected from at least one of non-woven fabrics, cotton fabrics or polyester fabrics;

Preferably, the water-absorbing material is selected from non-woven fabrics. Non-woven fabrics, also known as non-woven fabrics, are composed of oriented or random fibers. It is called cloth because of its appearance and certain properties. Polypropylene (pp material) pellets are mostly used as raw materials, and are produced by a continuous one-step method of high-temperature melting, spinning, laying, and hot-pressing and coiling. A new type of fiber product with a soft, breathable and flat structure, the advantage is that it does not produce lint, it is strong, durable, and silky soft, and it is also a kind of reinforcing material, and it also has a cotton feel. Compared with cotton fabrics, non-woven Cloth bags are easy to form and inexpensive to manufacture. In the present invention, the use of non-woven fabrics to make reference samples is more conducive to molding, and ensures good consistency between reference samples and samples.

Preferably, the waterproof material is selected from at least one of PP film, PE film or PET film.

Preferably, the antioxidant is selected from at least one of L-ascorbic acid, butylated hydroxyanisole, dibutylated hydroxytoluene and propyl gallate.

Antioxidants refer to food additives that can prevent or delay the oxidation of food, improve the stability of food and prolong the storage period. The correct use of antioxidants can not only prolong the storage period and shelf life of food, bring good economic benefits to producers and consumers, but also bring better food safety to consumers. The present invention preferably adopts L-ascorbic acid (vitamin C) to simulate the composition of spinach.

Preferably, the humectant is selected from at least one of propylene glycol, glycerol and sorbitol.

Moisturizers are a class of hydrophilic emollients that have the ability to bind water in the lower humidity range, replenishing the skin with moisture, and they can maintain the skin above normal by controlling the exchange of moisture between the product and the surrounding air. Balanced state of water content, play a role in reducing dry skin. The present invention selects at least one of propylene glycol, glycerol and sorbitol as the moisturizing agent, which can play a good moisturizing effect, is beneficial to the consistency between the samples of the reference sample for the fresh-keeping effect test, and makes the fresh-keeping test effect more accurate.

Preferably, the mass ratio of the antioxidant and the chlorophyll is 9-12:1, more preferably 10-11:1.

Typical but non-limiting mass ratios of antioxidants and chlorophyll are, for example, 9:1, 10:1, 11:1 or 12:1.

Preferably, the solvent of the mixed solution is water;

Preferably, the water is deoxygenated water, and a non-oxidizing protective gas is dissolved;

Preferably, the non-oxidizing protective gas is nitrogen.

In the present invention, the ultrapure water is measured according to the prepared amount, and the oxygen in the ultrapure water is removed by a vacuum pump or other degassing device, and the deoxygenation time is more than 30min, preferably 30-100min.

The process of filling nitrogen is as follows: after connecting the nitrogen bottle to the pipeline, the nozzle is close to the bottom of the container containing pure water, open the gas valve, and control the flow within 200ml/min for standby.

The preparation method of the reference sample for the fresh-keeping effect test as above, comprises the following steps:

The water-absorbing material, chlorophyll, humectant and antioxidant are contacted in a liquid environment; the production process is simple, the production efficiency is high, the consistency between reference samples and samples is good, and it can be widely used in the evaluation of the preservation effect of refrigerators and freezers , The inter-laboratory ability comparison of the fresh-keeping evaluation test of refrigerators and freezers, etc., has a wide range of application prospects.

Preferably, the contact time is 4-8 min, more preferably 5-6 min.

Typical but non-limiting times of contact are, for example, 4 min, 5 min, 6 min, 7 min or 8 min.

In a preferred embodiment, the preparation method of the reference sample for the fresh-keeping effect test comprises the following steps:

(a) Making packaging pouches: making packaging pouches with a breathable water-permeable film, with a size of 5-10cm×8-15cm, sewing three sides, and leaving one side as an opening;

(b) Making small pieces of water-absorbing material: stack the large-sized water-absorbing materials into 5-10 layers, and use a cutting tool to cut the 5-10 layers of water-absorbing material into small pieces, the size is 3-8cm×6-10cm, each A small portion of absorbent material separated by a waterproof material and stacked together;

(c) Deoxygenation of ultrapure water: measure ultrapure water according to the prepared amount, and use a vacuum pump or other degassing device to remove oxygen in the ultrapure water, and the deoxygenation time is 30-100min;

(d) Nitrogen filling: after connecting the nitrogen bottle to the pipeline, the nozzle is close to the bottom of the container containing pure water, open the gas valve, and control the flow within 200ml/min for standby;

(e) Weighing reagents: Weigh the antioxidant standard product with a one-thousandth of the balance; Weigh the chlorophyll standard product, the mass ratio of antioxidant and chlorophyll is 9-12:1, and use a cylinder to measure propylene glycol;

(f) Prepare the solution: dissolve the propylene glycol used for the weighed amount of chlorophyll, then pour it into a 1000ml volumetric flask, wash the graduated cylinder 3 times with an appropriate amount (about 15ml each time) of pure water filled with nitrogen, and the washing solution reaches the inlet 1000ml volumetric flask; add the weighed antioxidant to a 1000ml volumetric flask and dilute to 1000ml, cover and shake until the antioxidant is completely dissolved;

(g) Soaking: The water-absorbing materials separated by waterproof materials and stacked together are put into suitable plastic ziplock bags, poured into the solution in step (f) (operated in nitrogen environment) and soaked for 4-8 minutes.

(h) bagging: squeeze the soaked non-woven fabric under a certain pressure to remove excess liquid until no liquid drips, then put it into the bag in step (a), and seal it to obtain a reference for the preservation effect test Sample.

The application of the above-mentioned reference sample for fresh-keeping effect test in detecting the fresh-keeping effect of refrigerator and/or freezer. The experimental error of fresh-keeping fruit test is small, and the repeatability is good, and good comparison work can be carried out between different laboratories.

The present invention will be further described below with reference to specific embodiments and accompanying drawings.

Figure 1 shows the flow chart of the preparation process of the reference sample for the preservation effect test in Examples 1-4 of the present invention.

Example 1

A reference sample for fresh-keeping effect test, comprising a water-absorbing material, and a mixed solution of chlorophyll, a moisturizing agent and an antioxidant is absorbed in the water-absorbing material, and each water-absorbing material is separated by a waterproof material and packed in a breathable water-proof bag;

Among them, the antioxidant is L-ascorbic acid, the moisturizing agent is propylene glycol, the water-absorbing material is non-woven fabric, the number of layers of the non-woven fabric is 5, the size is 6cm×9cm, the waterproof material is PE film, and the specifications of the breathable water-proof bag are 8cm×11cm;

The preparation method of the reference sample for the fresh-keeping effect test comprises the following steps:

(a) Make a packaging pouch 8cm×11cm with a breathable water-permeable film, sew three sides, and leave one side as an opening;

(b) Lay the large-sized non-woven fabric into 5 layers and cut the 5-layer non-woven fabric into small pieces with a cutting tool, the size is 6cm×9cm, and each small piece of non-woven fabric is separated by PE film, then stacked together;

(c) measure 1000ml of ultrapure water according to the prepared amount, and use a vacuum pump or other degassing device to remove the oxygen in the ultrapure water, and the deoxygenation time is 30min;

(d) After connecting the nitrogen bottle to the pipeline, the nozzle is close to the bottom of the container containing pure water, open the air valve, and control the flow rate at 200ml/min for standby;

(e) Weighing reagents: Weigh 3g of L-ascorbic acid standard product with a one-thousandth balance; take 0.3g of chlorophyll standard product; use a 50ml graduated cylinder to measure 50ml of propylene glycol;

(f) Dissolve 50ml of propylene glycol for the amount of chlorophyll that has been weighed, then pour it into a 1000ml volumetric flask, wash the 50ml measuring cylinder 3 times with an appropriate amount (about 15ml each time) of nitrogen-filled pure water, and the washing liquid is in the inlet 1000ml volumetric flask; add the weighed L-ascorbic acid to a 1000ml volumetric flask and dilute to 1000ml, cover and shake until the L-ascorbic acid is completely dissolved;

(g) the non-woven fabrics separated by plastic wrap and stacked together are packed into suitable plastic ziplock bags, poured into the solution in step (f) (operated under nitrogen environment) and soaked for 5min;

(h) Squeeze the soaked non-woven fabric under a certain pressure to remove excess moisture, then put it into the bag in step (a), and seal it.

Example 2

A reference sample for fresh-keeping effect test, comprising a water-absorbing material, and a mixed solution of chlorophyll, a moisturizing agent and an antioxidant is absorbed in the water-absorbing material, and each water-absorbing material is separated by a waterproof material and packed in a breathable water-proof bag;

Among them, the antioxidant is L-ascorbic acid, the moisturizing agent is glycerin, the water-absorbing material is non-woven fabric, the number of layers of the non-woven fabric is 10, the size is 8cm×13cm, the waterproof material is PET film, and the air-permeable water-proof bag is The size is 10cm×15cm;

The preparation method of the reference sample for the fresh-keeping effect test comprises the following steps:

(a) Make a packaging pouch 10cm×15cm with a breathable water-permeable film, sew three sides, and leave one side as an opening;

(b) Lay the large-sized non-woven fabric into 10 layers, cut the 10-layer non-woven fabric into small pieces with a cutting tool, the size is 8cm×13cm, and each small piece of non-woven fabric is separated by a PET film , and then stacked together;

(c) measure 1000ml of ultrapure water according to the prepared amount, and use a vacuum pump or other degassing device to remove the oxygen in the ultrapure water, and the deoxygenation time is 60min;

(d) After connecting the nitrogen cylinder to the pipeline, the nozzle is close to the bottom of the container containing pure water, open the gas valve, and control the flow rate at 150ml/min for standby;

(e) weigh 3.3g of L-ascorbic acid standard with a one-thousandth of the balance; take 0.3g of chlorophyll standard; measure 50ml of glycerol with a 50ml graduated cylinder;

(f) Dissolve 50ml of glycerol for the weighed amount of chlorophyll, then pour it into a 1000ml volumetric flask, wash a 50ml graduated cylinder 3 times with an appropriate amount (about 15ml each) of nitrogen-filled pure water, and the washing solution into a 1000ml volumetric flask; add the weighed L-ascorbic acid to a 1000ml volumetric flask and dilute to 1000ml, cover and shake until the L-ascorbic acid is completely dissolved;

(g) the non-woven fabrics separated by plastic wrap and stacked together are packed into suitable plastic ziplock bags, poured into the solution in step (f) (operated under nitrogen environment) and soaked for 8min;

(h) Squeeze the soaked non-woven fabric under a certain pressure to remove excess liquid until no liquid drips, then put it into the bag in step (a), and seal it.

Example 3

A reference sample for fresh-keeping effect test, comprising a water-absorbing material, and a mixed solution of chlorophyll, a moisturizing agent and an antioxidant is absorbed in the water-absorbing material, and each water-absorbing material is separated by a waterproof material and packed in a breathable water-proof bag;

Among them, the antioxidant is butylated hydroxyanisole, the moisturizing agent is glycerin, the water-absorbing material is cotton, the number of layers of the cotton is 8, the size is 7cm×10cm, the waterproof material is PE film, and the specifications of the breathable water-proof bag are 9cm×12cm;

The preparation method of the reference sample for the fresh-keeping effect test comprises the following steps:

(a) Make a packaging pouch 9cm×12cm with a breathable water-permeable film, sew three sides, and leave one side as an opening;

(b) Stack the large-sized cotton cloth into 8 layers, cut the 8-layer cotton cloth into small pieces with a cutting tool, the size is 7cm×10cm, each small piece of cotton cloth is separated by PE film, and then stacked together ;

(c) measure 1000ml of ultrapure water according to the prepared amount, and use a vacuum pump or other degassing device to remove the oxygen in the ultrapure water, and the deoxygenation time is 50min;

(d) After connecting the nitrogen bottle to the pipeline, the nozzle is close to the bottom of the container containing pure water, open the gas valve, and control the flow rate at 130ml/min for standby;

(e) weigh 3.3g of butylated hydroxyanisole standard product with a one-thousandth of the balance; take 0.3g of chlorophyll standard product; measure 50ml of glycerol with a 50ml graduated cylinder;

(f) Dissolve 50ml of glycerol for the weighed amount of chlorophyll, then pour it into a 1000ml volumetric flask, wash a 50ml graduated cylinder 3 times with an appropriate amount (about 15ml each) of nitrogen-filled pure water, and the washing solution into a 1000ml volumetric flask; add the weighed butylated hydroxyanisole to a 1000ml volumetric flask and dilute to 1000ml, cover and shake until the butylated hydroxyanisole is completely dissolved;

(g) The cotton cloths separated by plastic wrap and stacked together are packed into suitable plastic ziplock bags, poured into the solution in step (f) (operated under nitrogen environment) and soaked for 8min;

(h) Squeeze the soaked cotton cloth under a certain pressure to remove excess liquid until no liquid drips, then put it into the bag in step (a), and seal it.

Example 4

A reference sample for fresh-keeping effect test, other operation steps are the same as those in Example 1, except that polyester cloth is used as the water-absorbing material.

Test example

Sampling and testing the amount of water, antioxidants and chlorophyll in the reference sample for the fresh-keeping effect test in Examples 1-4, as the initial value of the reference sample; standard deviation or uncertainty is calculated by multiple parallel sampling tests. The amount of water, antioxidants and chlorophyll was determined after placing it in the refrigerator for 3 days. The test results are shown in Table 1.

Moisture (%) Antioxidant (mg/100g) Chlorophyll (mg/100g) Reference sample initial value 90.5±1.7 330.0±6.23 30.0±0.50 refrigerator 1 8.0±0.5 225.0±5.44 23.0±0.56 refrigerator 2 12.0±0.8 261.0±7.15 21.5±0.45 refrigerator 3 10.0±0.7 240.0±6.42 22.0±0.55

The reference sample for the fresh-keeping effect test in the present invention includes a water-absorbing material, and the water-absorbing material absorbs a mixed solution of chlorophyll, a moisturizing agent and an antioxidant. The consistency of the reference sample is good, and it can be widely used in the evaluation of the preservation effect of refrigerators. The experimental error is small, and the repeatability is good.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention. scope.

Claims (14)

1. A reference sample for testing the preservation effect is characterized by comprising a water absorbing material, wherein a mixed solution of chlorophyll, a humectant and an antioxidant is absorbed in the water absorbing material;

the water absorption material is selected from at least one of non-woven fabric, cotton cloth or polyester fabric;

the antioxidant is selected from at least one of L-ascorbic acid, butyl hydroxy anisol, dibutyl hydroxy toluene and propyl gallate;

the humectant is at least one selected from propylene glycol, glycerol and sorbitol;

the mass ratio of the antioxidant to the chlorophyll is 9-12: 1;

the solvent of the mixed solution is water; the water is deoxidized water and is dissolved with non-oxidation protective gas.

2. The reference sample for testing freshness effectiveness according to claim 1, wherein the water absorbing material is contained in a breathable water-proof bag.

3. The reference sample for the preservation effect test according to claim 2, wherein the air-permeable and water-impermeable bag has a size of 5-10cm × 8-15 cm.

4. The reference sample for testing freshness effectiveness according to claim 1, wherein the water absorbing material is a plurality of layers, and each layer or each plurality of layers is separated by a waterproof material.

5. The reference sample for testing freshness effectiveness according to claim 4,

the water absorbing material is stacked by 5-10 pieces.

6. The reference sample for testing freshness effectiveness according to claim 4, wherein the water absorbing material of each layer has the same size or different sizes.

7. The reference sample for testing freshness effectiveness according to claim 4, wherein the water absorbent material has a size of 3 to 8cm × 6 to 13 cm.

8. The reference sample for the preservation effect test according to claim 4, wherein the waterproof material is at least one selected from a PP film, a PE film and a PET film.

9. The reference sample for the preservation effect test according to claim 1, wherein the mass ratio of the antioxidant to the chlorophyll is 10-11: 1.

10. the reference sample for testing freshness effectiveness according to claim 1, wherein the non-oxidizing protective gas is nitrogen.

11. The method for preparing a reference sample for freshness test according to any one of claims 1 to 10, comprising the steps of:

contacting the water absorbing material, chlorophyll, humectant and antioxidant in a liquid environment.

12. The method for preparing a reference sample for testing freshness effectiveness according to claim 11, wherein the contact time is 4-8 min.

13. The method for preparing a reference sample for testing freshness effectiveness according to claim 11, wherein the contact time is 5-6 min.

14. Use of a reference for testing the freshness protection effect according to any one of claims 1 to 10 for testing the freshness protection effect of a refrigerator and/or freezer.

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