Preparation method and application of oil oxidation type time-temperature indicator

Abstract

The application discloses an oil oxidation type time-temperature indicator, which comprises a sealed container which is partially or wholly transparent, vegetable oil and a thio-barbituric acid color developing agent which are packaged in the sealed container. The application mixes the vegetable oil and the thio-barbituric acid color developing agent to prepare an oxidation indicator, and the oxidation degree of food containing the same vegetable oil can be indicated by using the color developing reaction of the vegetable oil oxidation product and the thio-barbituric acid color developing agent, and the color change is irreversible. The oxidation indicator is packaged in the sealed container which is partially or wholly transparent, so that the oil oxidation indicator with small volume, convenient use and direct indication is prepared. The problem that the color change of the existing time-temperature indicator for food containing vegetable oil is not obvious or reversible is solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of food safety monitoring, and particularly relates to a preparation method of an oil oxidation type time-temperature indicator and application thereof. BACKGROUND

[0002] A time-temperature indicator (TTI) is a new type of indicator that produces a time-temperature cumulative effect by undergoing physical or chemical changes, thereby recording the temperature change history of a product and indicating the shelf life of the product, and has been used to monitor the safety of food, medicine and other products in real time.

[0003] Temperature is a key factor affecting the shelf life of food. For example, temperature can affect a series of changes such as food oil oxidation and microbial growth, which can easily lead to food safety and waste problems. Food waste and safety problems are related to date labels. Some products are still in good condition after the expiration date, while some products have deteriorated within the indicated shelf life due to storage temperature and other reasons. The shelf life marked on the traditional food packaging cannot truly reflect the quality deterioration of the food during actual transportation and storage. Therefore, it is crucial to monitor the influence of storage and transportation temperature on food quality indicators in real time.

[0004] However, the existing time-temperature indicator for food containing vegetable oil has the problems of inconspicuous color change or reversible color change. SUMMARY

[0005] The purpose of the present application is to solve the problem of inconspicuous color change or reversible color change of the existing time-temperature indicator for food containing vegetable oil.

[0006] The purpose of the present application is achieved by adopting the following technical solutions:

[0007] An oil oxidation type time-temperature indicator, comprising: a partially or wholly transparent sealed container, vegetable oil and a thio-barbituric acid developing agent encapsulated in the sealed container.

[0008] The thio-barbituric acid developing agent is prepared by mixing trichloroacetic acid, disodium ethylenediaminetetraacetate and thio-barbituric acid (TBA).

[0009] Preferably, the sealed container comprises a hard or soft transparent container.

[0010] Preferably, the sealed container comprises a sheet-shaped transparent container or a tubular transparent container.

[0011] Preferably, the capacity of the sealed container is 1-10 mL.

[0012] Preferably, the vegetable oil includes soybean oil.

[0013] Preferably, the volume ratio of the vegetable oil to the thiobarbituric acid colorimetric agent is 1:(6-150).

[0014] Preferably, the storage temperature of the indicator is below 0 °C.

[0015] Based on the same inventive concept, the present invention also provides a method for preparing a time-temperature indicator of grease oxidation, the method comprising the following steps:

[0016] S10. A thiobarbituric acid colorimetric reagent was prepared using trichloroacetic acid, disodium ethylenediaminetetraacetate, and thiobarbituric acid (TBA) in a volume ratio of 0.2:3:1.

[0017] S20. Prepare a mixed solution by mixing vegetable oil with thiobarbituric acid colorimetric reagent;

[0018] S30. Seal the mixed solution in a partially or completely transparent sealed container.

[0019] Based on the same inventive concept, the present invention also provides an application of an oil oxidation type time-temperature indicator, which is applied to the prediction of the shelf life of food, and the degree of color change of the oil oxidation indicator indicates the storage time and temperature process of the food.

[0020] Preferably, the color change of the oil oxidation indicator includes a change from colorless to light yellow, light pink, and even bright pink.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] This invention discloses a time-temperature indicator for oil oxidation, comprising: a partially or fully transparent sealed container, vegetable oil and a thiobarbituric acid color developer encapsulated within the sealed container. This invention prepares an oxidation indicator by mixing vegetable oil and the thiobarbituric acid color developer. It utilizes the color reaction between the vegetable oil oxide and the thiobarbituric acid color developer to indicate the degree of oxidation in foods containing the same vegetable oil, and the color change is irreversible. By encapsulating the oxidation indicator in a partially or fully transparent sealed container, a small, convenient, and directly clear oil oxidation indicator is created. This solves the problem that existing time-temperature indicators for foods containing vegetable oils often have unclear or reversible color changes. Attached Figure Description

[0023] Figure 1 This is a graph showing the trend of a* value over time under different volume ratios of oil and color developer at 47 ℃.

[0024] Figure 2 Figure 4 is a graph of the kinetic fitting curve of a* value at 47 °C with different volume ratios of oil and color developing agent;

[0025] Figure 3 Figure 5 is a graph of the change trend of a* value with time at 47 °C with different concentrations of color developing agent;

[0026] Figure 4 Figure 6 is a graph of the kinetic fitting curve of a* value at 47 °C with different concentrations of color developing agent;

[0027] Figure 5 Figure 7 is a color change process of color developing reaction at 47 °C. DETAILED DESCRIPTION

[0028] The technical solutions are further described below in combination with the drawings and specific examples to help understand the content of the present application.

[0029] Example 1

[0030] The present application discloses an oil oxidation type time-temperature indicator, which comprises a partially or wholly transparent sealed container, vegetable oil and a thiobarbituric acid color developing agent packaged in the sealed container.

[0031] The thiobarbituric acid color developing agent is prepared by mixing trichloroacetic acid, disodium ethylenediaminetetraacetate and thiobarbituric acid (TBA).

[0032] The sealed container comprises a transparent hard or soft container.

[0033] The sealed container comprises a sheet-shaped transparent container or a tubular transparent container.

[0034] The capacity of the sealed container is 1-10 mL, which can be 1 mL, 2 mL, 3 mL, 4 mL, 5 mL, 6 mL, 7 mL, 8 mL, 9 mL or 10 mL and any intermediate value of these values. A volume less than 1 mL is too small to be convenient for identification and use, and a volume greater than 10 mL will increase the cost of use and storage space.

[0035] The vegetable oil comprises soybean oil and other vegetable oils. Since the oil oxidation indicator utilizes the color developing reaction of vegetable oil oxidation product malondialdehyde and thiobarbituric acid to reflect the degree of oil oxidation, and since temperature and time can accelerate the degree of oxidation, the degree of oxidation of vegetable oil is determined according to the depth of color development, and the degree of oxidation of food containing the vegetable oil is determined. Since the oil oxidation indicator proposed by the present application is a sealed container, it is more suitable for monitoring the oxidation of food stored in a sealed manner.

[0036] The use method is that the oil oxidation indicator is placed together with the just finished food (containing the same or similar oxidation speed plant oil as the indicator), generally in the inside of the outer package, to maintain the same storage condition as the food, and the display color of the oil oxidation indicator is checked first when the food is checked or used, and the oxidation degree of the food is determined according to the pre-configured color card, so as to further determine whether the food can be safely eaten.

[0037] For convenience, the color card for determining the oxidation degree can be configured as a combination with the oil oxidation indicator, and can be pasted and fixed on one side of the oil oxidation indicator for easy comparison.

[0038] The volume ratio of the plant oil to the TBA color developing agent is 1: (6-150), and the same ratio is used for other oils.

[0039] The storage temperature of the indicator is lower than 0 ℃.

[0040] The specific manufacturing process includes:

[0041] (1) The TBA color developing agent is prepared by using trichloroacetic acid, disodium ethylenediaminetetraacetate and TBA in a volume ratio of 0.2:3:1.

[0042] (2) Selection of the volume ratio of the oil to the color developing agent: the volume of the sealed container is set to 3 mL, the oil volume to the volume of the TBA color developing agent is 1:150, 1:67, 1:30 and 1:6, the oil is mixed with the TBA color developing agent with the original concentration, the initial color of each system is measured, then it is stored in a 47 ℃ electric heating constant temperature incubator (DNP-9162, Shanghai Jinghong Experimental Equipment Co., Ltd.), and the change of the color a* value is measured every 24 hours. The instrument required for measuring the color is NS800 spectrophotometer (Shenzhen Times Peak Technology Co., Ltd.).

[0043] (2) Selection of the concentration of the color developing agent: the initial color of the aldehyde produced by the oil oxidation and the TBA reaction is colorless, and finally it becomes bright pink. In order to make the color developing reaction time longer, the higher the concentration of the color developing agent obtained by experiment, the longer the color developing reaction duration. 1 times, 1.25 times and 1.5 times the concentration of the TBA color developing agent is mixed with 0.1 mL of soybean oil, the initial color of the system is measured, then it is stored in a 47 ℃ constant temperature incubator, and the color change is measured every 24 hours.

[0044] (3) Color change result in the color developing reaction process: under the condition of 47 ℃, based on the optimal parameters (the volume ratio of the soybean oil to the color developing agent is 1:30, and the concentration of the color developing agent is 1.5 times), the color developing reaction change process is obtained.

[0045] The change trend of the color a* with time under different volume ratios of the soybean oil to the color developing agent is as follows: Figure 1and Figure 2 The a* value gradually increased with time at 47℃ under different volume ratios of oil and developer, and when the a* value was 50, the color parameter reached a maximum, and then tended to be flat, at which time the color reaction was saturated. Under the condition of a volume ratio of oil and developer of 1:30, the a* value changed more slowly than the other three ratios, and the color reaction time was longer (6 d). Under different ratios of oil and developer, the a* value increased exponentially with time when it did not reach the maximum, which was consistent with the change in the acid value in the moon cake. Therefore, the optimal volume ratio of oil and developer was selected to be 1:30, and the volume of oil was 0.1 mL.

[0046] The change trend of the color parameter a* with time under different developer concentrations is shown in Figure 3 and Figure 4 When the a* value was 50, the color parameter reached a maximum with time under different concentrations of developer. Based on the most obvious color change, the reaction time of 1-fold concentration developer was 6 d, 1.25-fold concentration reached 8 d, and 1.5-fold concentration of developer could reach 12 d. Because the color reaction rate was too fast, it would lead to the color gradient process not being easy to observe. In addition, TBA is a difficult-to-dissolve substance, and dissolving a large amount of TBA would lead to difficulties and time-consuming in the early operation, so the 1.5-fold concentration of developer was selected as the highest concentration of the indicator, which had a slower color reaction rate. The color reaction time could reach a longer coloration time compared to other commercial TTIs (time-temperature indicators) on the market, and the change in a* value was consistent with the first-order kinetic equation.

[0047] As can be seen from Figure 5 Under the condition of 47℃, based on the optimal parameters (volume ratio of soybean oil to developer of 1:30, and developer concentration of 1.5-fold), the color reaction change process of soybean oil as a substrate was experienced by colorless, light yellow, light pink, and bright pink, the color visualization was strong, and the color changed gradually.

[0048] The oil oxidation indicator (oil oxidation type time-temperature indicator) prepared in Example 1 can be used to indicate that the change rule of its quality index is consistent with the first-order kinetic equation and the actual storage environment may experience 47℃ of the product. The use of soybean oil in this embodiment does not mean that it is only suitable for soybean oil. Other vegetable oils can also be used to prepare the oil oxidation indicator by the preparation method provided in the present application. Replacing the oil does not affect the effectiveness of the prepared oil oxidation indicator. Because the oxidation speed of different oils is slightly different, replacing the oil to prepare the oil oxidation indicator only needs to recalibrate the color chart.

[0049] The present application can indicate the oxidation degree of food containing the same vegetable fat by using the color reaction of vegetable fat oxide and thio-barbituric acid color reagent, and the color change is irreversible; by packaging the oxidation indicator in a sealed container which is partially or entirely transparent, the oil oxidation indicator with small volume, convenient use and direct indication is prepared. The problems of color change not obvious or reversible of the existing time-temperature indicator for food containing vegetable fat are solved.

[0050] Example 2

[0051] Based on the same inventive concept, the present application further provides a preparation method of the oil oxidation type time-temperature indicator, which comprises the following steps:

[0052] S10. Thio-barbituric acid color reagent is prepared by using trichloroacetic acid, ethylenediamine tetraacetic acid disodium and thio-barbituric acid (TBA) at a volume ratio of 0.2:3:1;

[0053] S20. Vegetable fat is mixed with the thio-barbituric acid color reagent to prepare a mixed solution (indicator);

[0054] S30. The mixed solution is packaged in a sealed container which is partially or entirely transparent.

[0055] The oil oxidation type time-temperature indicator provided by the present application has significant and irreversible color change, and can effectively indicate the change of time and temperature.

[0056] The vegetable fat includes but is not limited to common edible vegetable oils such as soybean oil, peanut oil, rapeseed oil, sesame oil, sunflower oil, rice bran oil and corn oil; for food using vegetable oil A (which refers to a certain vegetable fat), the oil oxidation indicator is prepared by using vegetable oil A to achieve accurate vegetable oil oxidation indication effect.

[0057] The following takes the preparation of the indicator of the present application by using soybean oil as an example, and the specific implementation process is as follows:

[0058] The soybean oil is mixed with the thio-barbituric acid color reagent solution, and the mixed solution is independently packaged to obtain the oil oxidation type time-temperature indicator. Before formal use, it needs to be stored at low temperature below 0 ℃.

[0059] Further, the preparation process of the indicator is as follows: the most suitable volume ratio of soybean oil and color reagent is 1:30, and the volume of soybean oil is 0.1 mL; the original concentration of thio-barbituric acid color reagent is 1.5 times the concentration of the indicator.

[0060] The preparation method of the original concentration of the thio-barbituric acid developer is based on the MDA test kit for the convenience of implementation, but is not limited to the use of finished kits. The preparation of the thio-barbituric acid developer using the three reagents is as follows:

[0061] Reagent one: 20 mL of liquid C2HCl3O2 in one bottle, stored at room temperature;

[0062] Reagent two: 12 mL of liquid C 10 H 14 N2Na2O8·2H2O in one bottle, mixed with 340 mL of distilled water when used, and the reagent two application liquid was prepared, stored at 4°C.

[0063] Reagent three: TBA (C4H4N2O2S) powder in one bottle, heated to 90-100°C to dissolve thoroughly, then distilled water was added to 60 mL, and 60 mL of glacial acetic acid was added, mixed, and the reagent three application liquid (main component of the developer) was prepared. The prepared reagent was stored in the dark and refrigerated.

[0064] When the developer is prepared, the ratio of reagent one: reagent two: reagent three is 0.2:3:1. When the 1.25-fold and 1.50-fold concentration of the developer is prepared, the solvent volume is reduced proportionally.

[0065] The sealed container is an independent package with sealing properties.

[0066] The amount of the sealed container is 3 mL, and other arbitrary volumes can be used, depending on the specific needs of the user. In principle, the minimum volume limit is convenient for visual observation. The user can choose the appropriate amount according to their needs.

[0067] After the preparation of the thio-barbituric acid developer, soybean oil and the developer are mixed at a volume ratio of 1:30 to prepare an indicator. The volume of soybean oil is 0.1 mL, and the volume of the developer is 3 mL. Then the mixed liquid (indicator) is filled into a transparent sealed container to obtain the oil oxidation indicator.

[0068] The present application utilizes the color reaction of aldehydes, which are oxidation products of vegetable fats and oils, and thiobarbituric acid to make the color change of the time-temperature indicator more obvious, the color change is irreversible, the color development reaction time is longer; by adding trichloroacetic acid to promote the separation and precipitation of malondialdehyde, an oxidation product of oils and fats, the sensitivity of the color development reaction is improved to achieve more easily distinguishable color; by adding disodium ethylenediaminetetraacetate to improve the stability of the color development reaction. The present application has a simple preparation process and is easy to prepare; the present application also gives the relationship between the color life of the oil oxidation type time-temperature indicator and the preparation parameters, which is convenient for practical application.

[0069] Example 3

[0070] Based on the same inventive concept, the present application also provides an application of an oil oxidation type time-temperature indicator. The oil oxidation type time-temperature indicator as described in Example 1 is applied to the shelf life prediction of food, and the color change degree of the oil oxidation indicator is used to indicate the storage time and temperature history of the food.

[0071] As shown in Figure 5 , the color change degree of the oil oxidation indicator includes changing from colorless to light yellow, light pink and bright pink.

[0072] The above is only an embodiment of the present application and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application is included in the scope of the claims of the present application.

Claims

1. An oil oxidation type time-temperature indicator characterized by, The indicator comprises a sealed container which is partially or entirely transparent, a vegetable oil and a thiobarbituric acid color developing agent encapsulated in the sealed container; The thiobarbituric acid color developing agent is prepared by mixing trichloroacetic acid, disodium ethylenediaminetetraacetate and thiobarbituric acid (TBA); The volume ratio of the vegetable oil to the thiobarbituric acid color developing agent is 1: (6-150); The color developing reaction of the vegetable oil oxidant and the thiobarbituric acid color developing agent is used to indicate the oxidation degree of the food containing the same vegetable oil, and the color change is irreversible.

2. A fat oxidation type time-temperature indicator according to claim 1, characterized in that, The sealed container comprises a hard or soft transparent container.

3. A fat oxidation type time-temperature indicator according to claim 1, characterized in that, The sealed container comprises a sheet-shaped transparent container or a tubular transparent container.

4. The lipid oxidation time-temperature indicator of claim 1, wherein, The capacity of the sealed container is 1-10 mL.

5. A fat oxidation type time-temperature indicator according to claim 1, characterized in that, The vegetable oil comprises soybean oil.

6. A fat oxidation type time-temperature indicator according to claim 1, characterized in that, The storage temperature of the indicator is below 0 ℃.

7. A method of preparing a fat oxidation type time-temperature indicator, characterized by, The method comprises the following steps: S10. Using trichloroacetic acid, disodium ethylenediaminetetraacetate and thiobarbituric acid (TBA) to prepare a thiobarbituric acid color developing agent at a volume ratio of 0.2:3:1; S20. Mixing the vegetable oil with the thiobarbituric acid color developing agent to prepare a mixed solution; S30. Encapsulating the mixed solution in a sealed container which is partially or entirely transparent.

8. Use of an oil oxidation type time-temperature indicator, characterized in that, An oil oxidation type time-temperature indicator according to any one of claims 1-6 is applied to the shelf life prediction of food, and the color change degree of the oil oxidation indicator is used to indicate the history of the storage time and temperature of the food.

9. Use of an oil-oxidizable time-temperature indicator according to claim 8, characterized in that, The color change degree of the oil oxidation indicator comprises a change from colorless to light yellow, light pink and bright pink.

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