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

Abstract

The invention discloses a grease oxidation type time-temperature indicator. The indicator comprises a partially or completely transparent sealed container, vegetable fat and a thiobarbituric acid color developing agent, wherein the vegetable fat and the thiobarbituric acid color developing agent are packaged in the sealed container. The oxidation indicator is prepared by mixing the vegetable fat and the thiobarbituric acid color developing agent, the oxidation degree of food containing the same vegetable fat can be indicated through the color developing reaction of the vegetable fat oxide and the thiobarbituric acid color developing agent, and meanwhile color changing is irreversible; the oxidation indicator is packaged in a partially or completely transparent sealed container, so that the grease oxidation indicator which is small in size, convenient to use and direct and clear in indication is manufactured. The problem that an existing time-temperature indicator for food containing vegetable fat is not obvious in color change or reversible in color change is solved.

Description

Technical Field

[0001] The invention belongs to the field of technology, and in particular relates to a preparation method and application of a grease oxidation type time-temperature indicator. Background Art

[0002] Time-temperature integrator (TTI) is a new type of indicator that produces a time-temperature accumulation effect through physical or chemical changes, thereby recording the temperature change history of the product and indicating the shelf life of the product. It 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 the oxidation of food fats and the growth of microorganisms, which can easily lead to food safety and waste issues. Food waste and safety issues are both related to date labels. Some products are still intact after the shelf life has passed, while others have deteriorated within the shelf life due to storage temperature and other reasons. The shelf life marked on traditional food packaging cannot truly reflect the quality deterioration of food during actual transportation and storage. Therefore, real-time monitoring of the impact of storage and transportation temperature on food quality indicators is crucial.

[0004] However, existing time-temperature indicators for foods containing vegetable oils and fats have the problem that the color change is not obvious or the change is reversible. Summary of the invention

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

[0006] The purpose of the present invention is to adopt the following technical solutions to achieve:

[0007] A fat oxidation time-temperature indicator, the indicator comprising: a partially or completely transparent sealed container, vegetable fat and thiobarbituric acid developer encapsulated in the sealed container;

[0008] The thiobarbituric acid developer is prepared by mixing trichloroacetic acid, disodium ethylenediaminetetraacetate and thiobarbituric 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 comprises soybean oil.

[0013] Preferably, the volume ratio of the vegetable oil to the thiobarbituric acid developer 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 fat oxidation time-temperature indicator, characterized in that the method comprises the following steps:

[0016] S10. Prepare thiobarbituric acid color developer using trichloroacetic acid, disodium ethylenediaminetetraacetate and thiobarbituric acid (TBA) in a volume ratio of 0.2:3:1;

[0017] S20. Mixing the vegetable oil and thiobarbituric acid color developer to prepare a mixed solution;

[0018] S30. Encapsulate 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 a fat oxidation time-temperature indicator, characterized in that a fat oxidation time-temperature indicator as described in any one of claims 1 to 7 is applied to the shelf life prediction of food, and the storage time and temperature history of the food are indicated by the degree of color change of the fat oxidation indicator.

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

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The invention discloses a fat oxidation time-temperature indicator, which comprises: a partially or completely transparent sealed container, a vegetable fat encapsulated in the sealed container, and a thiobarbituric acid developer. The invention prepares an oxidation indicator by mixing vegetable fat and thiobarbituric acid developer, and can use the color reaction of vegetable fat oxide and thiobarbituric acid developer to indicate the oxidation degree of food containing the same vegetable fat, and the color change is irreversible; by encapsulating the oxidation indicator in a partially or completely transparent sealed container, a fat oxidation indicator with small volume, convenient use, and direct and clear indication is prepared. The invention solves the problem that the color change of existing time-temperature indicators for food containing vegetable fat is not obvious or the change is reversible. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a graph showing the change trend of a* value over time at different volume ratios of oil and developer at 47°C;

[0024] Figure 2 It is the kinetic fitting curve of a* value at different volume ratios of oil and developer at 47℃;

[0025] Figure 3 This is the trend graph of a* value changing with time at different developer concentrations at 47°C;

[0026] Figure 4 It is the kinetic fitting curve diagram of a* value at different developer concentrations at 47℃;

[0027] Figure 5 It is the color change process of the color development reaction at 47°C. DETAILED DESCRIPTION

[0028] The technical solution is further described below in conjunction with the accompanying drawings and specific embodiments to help understand the content of the present invention.

[0029] Example 1

[0030] The invention discloses a fat oxidation time-temperature indicator, which comprises: a partially or completely transparent sealed container, vegetable fat and thiobarbituric acid developer encapsulated in the sealed container;

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

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

[0033] The sealed container includes a sheet-shaped transparent container or a tube-shaped transparent container.

[0034] The capacity of the sealed container is 1-10 mL. The capacity of the sealed container 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 values ​​thereof. A volume below 1 ml is too small to be easily identified and used, and a volume above 10 ml will increase the use cost and storage space.

[0035] The vegetable oils include soybean oil and other vegetable oils. Because the oil oxidation indicator uses the color reaction of malondialdehyde, an oxide of vegetable oil, and thiobarbituric acid to reflect the degree of oil oxidation, and because both temperature and time accelerate the degree of oxidation, the degree of oxidation of the vegetable oil is determined according to the depth of the color, and then the degree of oxidation of the food containing the vegetable oil is determined. Since the oil oxidation indicator proposed by the present invention is a sealed container, it is more suitable for oxidation monitoring of sealed stored food.

[0036] Instructions for use: Place the oil oxidation indicator together with freshly prepared food (including food with the same vegetable oil as the indicator or with a similar oxidation rate), generally inside the outer packaging, to maintain the same storage conditions as the food. When inspecting or using food, first check the displayed color of the oil oxidation indicator, and determine the degree of oxidation of the food based on the pre-configured color card to further determine whether it is safe to eat.

[0037] For convenience, the color card used to determine the degree of oxidation 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 vegetable oil to the thiobarbituric acid developer is 1:(6-150), and other oils use the same ratio.

[0039] The storage temperature of the indicator is below 0°C.

[0040] The specific production process includes:

[0041] (1) using trichloroacetic acid, disodium ethylenediaminetetraacetate and thiobarbituric acid (TBA) in a volume ratio of 0.2:3:1 to prepare a thiobarbituric acid color developer;

[0042] (2) Selection of the volume ratio of oil to color developer: The volume of the sealed container was set to 3 mL, and the oil volume ratios of 1:150, 1:67, 1:30, and 1:6 were mixed with the original concentration of thiobarbituric acid color developer, and the initial color of each system was measured. Then, the mixture was placed in a 47°C electric constant temperature incubator (DNP-9162, Shanghai Jinghong Experimental Equipment Co., Ltd.) for storage, and the change in the color a* value was measured every 24 hours. The instrument required for color measurement is NS800 spectrophotometer (Shenzhen Times Peak Technology Co., Ltd.).

[0043] (2) Selection of color developer concentration: The initial color of the reaction between aldehydes, a product of oil oxidation, and TBA is colorless, and eventually turns bright pink. In order to extend the color development time, the higher the color developer concentration, the longer the color development time. Mix 1x, 1.25x, and 1.5x the concentration of thiobarbituric acid color developer with 0.1 mL of soybean oil, measure the initial color of the system, and then store it at a constant temperature of 47°C, and measure the color change every 24 hours.

[0044] (3) Color change results during the color development reaction: The color development reaction process at 47°C using soybean oil as the substrate based on the optimal parameters (volume ratio of soybean oil to color developer is 1:30, and the concentration of color developer is 1.5 times).

[0045] The variation trend of color parameter a* with different volume ratios of soybean oil to color developer over time is shown in Figure 1 and Figure 2 As shown. At 47℃, the a* value gradually increased with time under different volume ratios of oil to color developer. When the a* value was 50, the color parameter reached the maximum, and then tended to be flat. At this time, the color reaction was saturated. When the volume ratio of oil to color developer was 1:30, the change of a* value was the slowest compared with the other three ratios, and the color reaction time was longer (6d). Under different ratios of oil to color developer, the a* value increased exponentially with time before reaching the maximum, which was consistent with the change law of acid value in moon cakes. Therefore, the optimal volume ratio of oil to color developer was 1:30, and the oil volume was 0.1mL.

[0046] The variation trend of color parameter a* with different developer concentrations over time is shown in Figure 3 and Figure 4 As shown. When the a* value is 50, the color parameter reaches the maximum with time extension under different concentrations of color developer. Based on the most obvious color change, the reaction time of 1 times the concentration of color developer is 6 days, 1.25 times the concentration reaches 8 days, and 1.5 times the concentration of color developer can reach 12 days. Because the color development reaction rate is too fast, the color gradient process is not easy to observe; in addition, TBA is a poorly soluble substance, and dissolving a large amount of TBA will make the initial operation difficult and time-consuming. Therefore, the color development reaction rate is relatively slow. 1.5 times the color developer concentration is selected as the highest concentration of the indicator. Compared with other commercial TTIs (time-temperature indicators) on the market, this color development reaction time can achieve a longer color development time, and the change of a* value conforms to the first-order kinetic equation.

[0047] from Figure 5 It can be seen that under 47°C conditions, with soybean oil as the substrate, the color development reaction changes based on the optimal parameters (the volume ratio of soybean oil to color developer is 1:30, and the concentration of color developer is 1.5 times). The process specifically goes through the changes from colorless, light yellow, light pink, to bright pink. The color visualization is strong and changes step by step in a gradient.

[0048] The oil oxidation indicator (oil oxidation time-temperature indicator) prepared in Example 1 can be used to indicate products whose quality index change law conforms to the first-order kinetic equation and whose actual storage environment may experience 47°C. The use of soybean oil in this embodiment does not mean that it is only applicable to soybean oil. Other vegetable oils can also be used to prepare the oil oxidation indicator using the preparation method provided by the present invention. Replacing the oil does not affect the effectiveness of the prepared oil oxidation indicator. Since the oxidation speeds of different oils are slightly different, replacing the oil to make the oil oxidation indicator only requires recalibrating the comparison color card.

[0049] The present invention prepares an oxidation indicator by mixing vegetable oil and thiobarbituric acid color developer, and can use the color reaction of vegetable oil oxide and thiobarbituric acid color developer to indicate the oxidation degree of food containing the same vegetable oil, and the color change is irreversible; by encapsulating the oxidation indicator in a partially or completely transparent sealed container, a small-volume, easy-to-use, direct and clear oil oxidation indicator is prepared. The problem that the existing time-temperature indicator for food containing vegetable oil has no obvious color change or the change is reversible is solved.

[0050] Example 2

[0051] Based on the same inventive concept, the present invention also provides a method for preparing a fat oxidation type time-temperature indicator, the method comprising the following steps:

[0052] S10. Prepare thiobarbituric acid color developer using trichloroacetic acid, disodium ethylenediaminetetraacetate and thiobarbituric acid (TBA) in a volume ratio of 0.2:3:1;

[0053] S20. Mixing the vegetable oil and thiobarbituric acid color developer to prepare a mixed solution (indicator);

[0054] S30. Encapsulate the mixed solution in a partially or completely transparent sealed container.

[0055] The grease oxidation time and temperature indicator provided by the present invention has a significant and irreversible color change and can effectively indicate changes in time and temperature.

[0056] Vegetable oils and fats include but are not limited to soybean oil, peanut oil, rapeseed oil, sesame oil, sunflower oil, rice bran oil, corn oil and other common edible vegetable oils; for foods using vegetable oil A (referring to a certain vegetable oil), vegetable oil A is used to make an oil oxidation indicator to achieve an accurate vegetable oil oxidation indication effect.

[0057] Taking soybean oil as an example to make the indicator of the present invention, the specific implementation process is as follows:

[0058] The soybean oil and the thiobarbituric acid color developer solution are mixed, and the mixed solution is packaged independently to obtain a fat oxidation type time-temperature indicator. Before formal use, it needs to be stored at a low temperature below 0°C.

[0059] Furthermore, the indicator preparation process is as follows: the optimum volume ratio of soybean oil to color developer is 1:30, the volume of soybean oil is 0.1 mL; the original concentration of thiobarbituric acid color developer is 1.5 times the concentration of the indicator.

[0060] The preparation method of the original concentration of the thiobarbituric acid color developer is based on the MDA test kit for the convenience of implementation (but not limited to the use of finished test kits, and the preparation can also be implemented using raw materials with the same components). The malondialdehyde (MDA) test kit used in this embodiment is produced by Nanjing Jiancheng Biological Research Institute, item number: A003-1, which contains reagent one, reagent two and reagent three. The process of using these three reagents to prepare the thiobarbituric acid color developer is as follows:

[0061] Reagent 1: Trichloroacetic acid (C 2 HCl 3 O 2 ) Liquid 20mL x 1 bottle, stored at room temperature;

[0062] Reagent 2: Disodium ethylenediaminetetraacetate (C 10 H 14 N 2 Na 2 O 8 ·2H 2 O) Liquid 12mL x 1 bottle, add 340mL of distilled water to each bottle and mix well to prepare reagent 2 application solution, refrigerate at 4℃;

[0063] Reagent 3: Thiobarbituric acid (TBA) (C 4 H 4 N 2 O 2 S) Powder x 1 tube. When using, add 60 mL of distilled water to the powder, heat to 90℃~100℃ to fully dissolve, then add distilled water to 60 mL, then add 60 mL of glacial acetic acid, mix well, and prepare the reagent three application solution (the main component of the color developer). The prepared reagent should be refrigerated away from light.

[0064] When preparing the color developer, the ratio of reagent 1: reagent 2: reagent 3 is 0.2:3:1. When preparing the color developer with a concentration of 1.25 times and 1.50 times, the volume of the solvent is reduced in the same proportion.

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

[0066] The volume of the sealed container is 3 mL, and any other volume is acceptable, depending on the specific usage requirements. In principle, the minimum volume limit is based on visual convenience. Users can choose the appropriate volume according to their needs.

[0067] After the thiobarbituric acid color developer is prepared, soybean oil and the color developer are mixed at a volume ratio of 1:30 to prepare an indicator, wherein the volume of the soybean oil is 0.1 mL and the volume of the color developer is 3 mL; and then the mixed liquid (indicator) is placed in a transparent sealed container and sealed to obtain the oil oxidation indicator.

[0068] The present invention utilizes the color development reaction of aldehydes, a product of plant oil oxidation, and thiobarbituric acid, so that the color change of the time-temperature indicator is more obvious, the color change is irreversible, and the color development time is longer; trichloroacetic acid is added to promote the separation and precipitation of malondialdehyde, an oxidized oil, and the sensitivity of the color development reaction is improved to achieve easier color distinction; disodium ethylenediaminetetraacetic acid is added to improve the stability of the color development reaction. The present invention has a simple preparation process and is easy to prepare; the present invention also provides 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 invention also provides an application of a fat oxidation time-temperature indicator, in which a fat oxidation time-temperature indicator as described in Example 1 is applied to the shelf life prediction of food, and the degree of color change of the fat oxidation indicator is used to indicate the storage time and temperature history of the food.

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

[0072] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of the claims of the present invention.

Claims

1. A grease oxidation time-temperature indicator, characterized in that: The indicator comprises: a partially or completely transparent sealed container, vegetable oil and thiobarbituric acid color developer encapsulated in the sealed container; The thiobarbituric acid developer is prepared by mixing trichloroacetic acid, disodium ethylenediaminetetraacetate and thiobarbituric acid (TBA).

2. A grease oxidation time-temperature indicator as claimed in claim 1, characterized in that: The sealed container includes a hard or soft transparent container.

3. A grease oxidation time-temperature indicator as claimed in claim 1, characterized in that: The sealed container includes a sheet-shaped transparent container or a tube-shaped transparent container.

4. A grease oxidation time-temperature indicator as claimed in claim 1, characterized in that: The capacity of the sealed container is 1-10 mL.

5. A grease oxidation time-temperature indicator as claimed in claim 1, characterized in that: The vegetable oil includes soybean oil.

6. A grease oxidation time-temperature indicator as claimed in claim 1, characterized in that: The volume ratio of the vegetable oil to the thiobarbituric acid developer is 1:(6-150).

7. A grease oxidation time-temperature indicator as claimed in claim 1, characterized in that: The storage temperature of the indicator is below 0°C.

8. A method for preparing a fat oxidation time-temperature indicator, characterized in that: The method comprises the following steps: S10. Prepare thiobarbituric acid color developer using trichloroacetic acid, disodium ethylenediaminetetraacetate and thiobarbituric acid (TBA) in a volume ratio of 0.2:3:1; S20. Mixing the vegetable oil and thiobarbituric acid color developer to prepare a mixed solution; S30. Encapsulate the mixed solution in a partially or completely transparent sealed container.

9. An application of a grease oxidation time-temperature indicator, characterized in that: The fat oxidation time-temperature indicator according to any one of claims 1 to 7 is applied to the prediction of the shelf life of food, and the storage time and temperature history of the food are indicated by the degree of color change of the fat oxidation indicator.

10. The use of a fat oxidation time-temperature indicator as claimed in claim 9, characterized in that: The color change degree of the oil oxidation indicator includes changing from colorless to light yellow, light pink and finally bright pink.

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