A detection method for apricot fruit leather drying temperature

Abstract

The application discloses a detection method for apricot fruit drying temperature, comprising the following steps: S1, dried fruit pretreatment; S2, electrode modification and treatment, S2-1, the solution obtained in step S1-3 is added dropwise into a gold electrode which has been cleaned on the surface, and the solvent is naturally volatilized to complete the modification of the gold electrode; S2-2, the modified gold electrode is immersed into a 0.1M sodium hydroxide solution and then into water for cleaning; S2-3, the gold electrode treated in step S2-2 is used as a working electrode and is immersed into a phosphate buffer solution together with a platinum wire electrode and an Ag / AgCl (3MKCl) electrode; S3, current determination; S4, determination of the drying temperature. The above technical scheme is simple in operation and fast in response time, and in addition, the catalase activity in the apricot fruit produced by different drying temperatures is different, and the current value will show great difference, so that the drying temperature for producing the apricot fruit can be accurately detected through the determination of the current.

Description

Technical Field

[0001] This invention belongs to the field of detection technology and relates to a detection technology that can rapidly determine the drying temperature of almond preserve samples during processing. The method of this invention involves electrochemical analysis. Background Technology

[0002] In recent years, the consumption of dried fruit as a healthy snack has increased dramatically. To meet the growing demand for dried fruit, the fruit drying industry is focusing more on mass production and less on nutrient preservation and drying conditions. Fruit drying generally employs various methods such as convection hot air drying, freeze drying, vacuum drying, microwave drying, and infrared drying. Among these methods, hot air drying is the most commonly used because it is simple to operate, requires little investment, and has low operating costs. However, this process leads to the loss of valuable nutrients in the fruit. The nutritional quality of dried fruit is directly related to drying conditions, especially temperature. Drying at temperatures ≥80℃ can cause various degradation reactions, affecting not only the sensory properties of the fruit (color, texture, and flavor) but also destroying the most valuable nutrients (vitamins, enzymes, carotenoids, antioxidants, and other bioactive components or phytochemicals). Lower drying temperatures, such as 40℃, are better for preserving the fruit's natural components. However, there are no strict regulations for fruit drying; companies are free to choose the drying temperature that best suits their needs. Typically, fruit is placed at high temperatures for drying to reduce drying time. Nowadays, consumers are increasingly concerned about the nutritional value of food. Therefore, it is crucial to assess the quality degradation of dried fruits due to heat exposure and to ensure that consumers consume dried fruits rich in health-promoting nutrients.

[0003] However, there is currently no method on the market that can serve as a quick and accurate indicator for evaluating the heat exposure of dried fruit managers. Summary of the Invention

[0004] In view of the shortcomings of the prior art, this invention proposes a method for detecting the drying temperature of dried almonds. Based on the electrochemical detection of the intensity of catalase activity in dried fruit, this invention uses dried almonds as the target and reverse-engineers the temperature at which the dried fruit has been exposed to heat.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A method for detecting the drying temperature of dried almonds includes the following steps:

[0007] S1. Dried fruit pretreatment

[0008] S1-1. Weigh out the dried almonds, grind them thoroughly into a paste, add them to water, and sonicate thoroughly.

[0009] S1-2. Filter the aqueous solution containing almond preserves to obtain the extract;

[0010] S1-3. Weigh the pre-prepared chitosan solution and add it to the extraction solution, then sonicate to obtain a homogenized solution.

[0011] S2, Electrode Modification and Treatment

[0012] S2-1. Take the solution obtained in step S1-3 and add it dropwise to the gold electrode after surface cleaning. Let the solvent evaporate naturally to complete the modification of the gold electrode.

[0013] S2-2. Immerse the modified gold electrode in a 0.1M sodium hydroxide solution, and then rinse it in water.

[0014] S2-3. Use the gold electrode processed in step S2-2 as the working electrode, and immerse it together with the platinum wire electrode and the Ag / AgCl (3MKCl) electrode in a phosphate buffer solution.

[0015] S3, Current measurement;

[0016] S4. Determination of drying temperature.

[0017] Preferably, in step S1-1, the weight of the almond preserves is 0.5-3g, and the water is 5-20ml.

[0018] Preferably, in steps S1-2, the filter paper used for filtration has a pore size of 0.2μm to 1μm.

[0019] Preferably, in steps S1-3, the concentration of chitosan is 0.5-1%, and the amount added is 0.1-0.2 mL.

[0020] Preferably, in step S2-1, the solution added to the surface of the gold electrode is 2-4 μL.

[0021] Preferably, in step S2-2, the immersion time in sodium hydroxide is 30s to 1min.

[0022] Preferably, in steps S2-3, the concentration of the phosphate buffer solution is 0.1-0.2M.

[0023] Preferably, in step S3, the current measurement method is as follows: set the potential to -0.3V and perform timing current measurement. After the current stabilizes, add 0.2mL of hydrogen peroxide solution of a certain concentration to the solution, observe the change in current, and record the current value after stabilization.

[0024] Preferably, in step S3, the concentration of hydrogen peroxide is 0.2–0.3 mM.

[0025] Preferably, in step S4, the standard for determining the drying temperature is as follows: if the current value is in the range of 1-10 μA, the drying temperature of the almond preserves is considered to be ≥80℃; if the current value is in the range of 11-60 μA, the drying temperature of the almond preserves is considered to be ≥60℃ but <80℃; if the current value is in the range of 61-80 μA, the drying temperature of the almond preserves is considered to be ≥40℃ but <60℃; and if the current value is greater than 80 μA, the drying temperature of the almond preserves is considered to be <40℃.

[0026] This invention has the following characteristics and beneficial effects:

[0027] Using the above technical solution, electrochemical analysis technology eliminates the need for complex sample processing and experimental operations, requires no special detection equipment, has low detection cost, is easy to operate, and has a fast response time. In addition, since the activity of catalase in almond preserves produced at different drying temperatures varies, the current value will show a large difference. Therefore, by measuring the current, the drying temperature for producing almond preserves can be accurately detected. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0029] This invention provides a method for detecting the drying temperature of dried almonds, comprising the following steps:

[0030] S1. Dried fruit pretreatment

[0031] S1-1. Weigh out the dried almonds, grind them thoroughly into a paste, add them to water, and sonicate thoroughly.

[0032] S1-2. Filter the aqueous solution containing almond preserves to obtain the extract;

[0033] S1-3. Weigh the pre-prepared chitosan solution and add it to the extraction solution, then sonicate to obtain a homogenized solution.

[0034] S2, Electrode Modification and Treatment

[0035] S2-1. Take the solution obtained in step S1-3 and add it dropwise to the gold electrode after surface cleaning. Let the solvent evaporate naturally to complete the modification of the gold electrode.

[0036] S2-2. Immerse the modified gold electrode in a 0.1M sodium hydroxide solution, and then rinse it in water.

[0037] S2-3. Use the gold electrode processed in step S2-2 as the working electrode, and immerse it together with the platinum wire electrode and the Ag / AgCl (3MKCl) electrode in a phosphate buffer solution.

[0038] S3, Current measurement;

[0039] S4. Determination of drying temperature.

[0040] Specifically, in step S1-1, the weight of the almond preserves is 0.5-3g and the water is 5-20ml. Too little almond preserves sample is not conducive to showing the overall properties, while too much will make it difficult to disperse by ultrasound. Too little water is not conducive to the subsequent filtration of the extract, while too much will reduce the concentration of catalase.

[0041] Specifically, in steps S1-2, the filter paper used for filtration is selected with a pore size of 0.2μm to 1μm. If the pore size is too small, the filtration efficiency will be reduced, and if the pore size is too large, there will be too many solid particles in the extract, which will affect the detection accuracy.

[0042] Specifically, in steps S1-3, the concentration of chitosan is 0.5-1%, and the amount added is 0.1-0.2 mL.

[0043] Understandably, the chitosan solution serves to aid in film formation during subsequent electrode modification. Excessive concentration or dosage can lead to an overly thick film, while insufficient concentration or dosage hinders successful film formation.

[0044] Specifically, in step S2-1, the solution added to the surface of the gold electrode is 2-4 μL.

[0045] Specifically, in step S2-2, the immersion time in sodium hydroxide is 30 seconds to 1 minute. Too little time is detrimental to the activation of catalase, while too much time will affect the integrity of the electrode membrane.

[0046] Specifically, in steps S2-3, the concentration of the phosphate buffer solution is 0.1–0.2 M.

[0047] Specifically, in step S3, the current measurement method is as follows: The potential is set to -0.3V for timing current measurement. After the current stabilizes, 0.2 mL of a certain concentration of hydrogen peroxide solution is added to the solution, the change in current is observed, and the current value after stabilization is recorded. Because the activity of catalase in almond preserves produced at different drying temperatures varies, the current values ​​will show significant differences.

[0048] The concentration of hydrogen peroxide is 0.2–0.3 mM. Too low a concentration will result in a correspondingly small current, making it difficult to calculate different drying temperatures. Too high a concentration will result in an excessively high background current and large current fluctuations, leading to decreased reproducibility of the results.

[0049] Specifically, in step S4, the standard for determining the drying temperature is as follows: if the current value is in the range of 1-10μA, the drying temperature of the almond preserves is considered to be ≥80℃; if the current value is in the range of 11-60μA, the drying temperature of the almond preserves is considered to be ≥60℃ but <80℃; if the current value is in the range of 61-80μA, the drying temperature of the almond preserves is considered to be ≥40℃ but <60℃; and if the current value is greater than 80μA, the drying temperature of the almond preserves is considered to be <40℃.

[0050] The following specific embodiments are provided to illustrate the above technical solutions:

[0051] Example 1

[0052] The following is an example of measuring the quality of a dried almond preserve made at 35°C using Example 1.

[0053] Grind 1g of dried almonds thoroughly into a paste, add 10mL of water, and sonicate thoroughly. Filter the aqueous solution containing the almond paste through filter paper with a 1μm pore size to obtain the extract. Prepare a 1% chitosan solution, add 0.2mL to the extract, and sonicate until homogeneous.

[0054] 2 μL of the solution was added dropwise to a surface-cleaned commercial gold electrode, and the solvent was allowed to evaporate naturally. The modified gold electrode was then immersed in a 0.1 M sodium hydroxide solution for 30 s, followed by rinsing in water. The treated electrode, along with a platinum wire electrode and an Ag / AgCl (3 M KCl) electrode, was immersed in a 0.1 M phosphate buffer solution. A chronoamperometry test was performed with the potential set at -0.3 V. After the current stabilized, 0.2 mL of hydrogen peroxide solution (0.3 mM) was added dropwise, and the stable current of 89.7 μA was recorded. A current value greater than 80 μA indicates that the drying temperature of the almond preserves is <40℃.

[0055] Example 2

[0056] The following is an example of measuring the quality of a type of dried almond preserve prepared at 50°C using Example 2.

[0057] Grind 0.5g of dried almonds thoroughly into a paste, add 5mL of water, and sonicate thoroughly. Filter the aqueous solution containing the almond paste through 0.5μm filter paper to obtain the extract. Prepare a 0.5% chitosan solution, add 0.1mL to the extract, and sonicate until homogeneous.

[0058] Add 3 μL of the solution dropwise to a surface-cleaned commercial gold electrode and allow the solvent to evaporate naturally. Immerse the modified gold electrode in a 0.1 M sodium hydroxide solution for 1 min, then rinse it in water. Use the treated electrode as the working electrode, along with a platinum wire electrode and an Ag / AgCl (3 M KCl) electrode, in a 0.2 M phosphate buffer solution. Set the potential to -0.3 V and perform chronoamperometry. After the current stabilizes, add 0.2 mL of hydrogen peroxide solution (0.2 mM) to the solution and record the stable current of 71.2 μA. A current value in the range of 61-80 μA indicates that the drying temperature of the almond preserves is ≥40℃ but <60℃.

[0059] Example 3

[0060] The following is an example of measuring the quality of a type of dried almond preserve made at 80°C using Example 3.

[0061] Grind 2g of dried almonds thoroughly into a paste, add 20mL of water, and sonicate thoroughly. Filter the aqueous solution containing the almond paste through 0.5μm filter paper to obtain the extract. Prepare a 1% chitosan solution, add 0.1mL to the extract, and sonicate until homogeneous.

[0062] Add 4 μL of the solution dropwise to a surface-cleaned commercial gold electrode and allow the solvent to evaporate naturally. Immerse the modified gold electrode in a 0.1 M sodium hydroxide solution for 30 s, then rinse it in water. Use the treated electrode as the working electrode, along with a platinum wire electrode and an Ag / AgCl (3 M KCl) electrode, in a 0.1 M phosphate buffer solution. Set the potential to -0.3 V and perform chronoamperometry. After the current stabilizes, add 0.2 mL of hydrogen peroxide solution (0.2 mM) to the solution and record the stable current of 9.2 μA. A current value in the range of 1-10 μA indicates that the drying temperature of the almond preserves is ≥80℃.

[0063] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments, including components, without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A method for detecting the drying temperature of apricot fruit leather, characterized by, It comprises the following steps: S1, pretreatment of dried fruit S1-1, weigh apricot fruit leather, add water after grinding into mud, and ultrasonic; S1-2, filter the water solution containing apricot fruit leather mud to obtain an extract; S1-3, weigh the pre-configured chitosan solution and add it to the extract, and ultrasonic to obtain a solution; S2, electrode modification and treatment S2-1, add the solution obtained in step S1-3 to the surface cleaned gold electrode, and wait for the solvent to evaporate naturally to complete the modification of the gold electrode; S2-2, immerse the modified gold electrode in 0.1M sodium hydroxide solution and then in water; S2-3, use the gold electrode treated in step S2-2 as a working electrode, and immerse it in a phosphate buffer solution together with a platinum wire electrode and an Ag / AgCl (3M KCl) electrode; S3, current determination, set the potential at -0.3V for chronoamperometric determination, add 0.2mL of hydrogen peroxide solution of a certain concentration to the solution after the current stabilizes, observe the change of current, and record the stable current value; S4, determination of drying temperature, the standard for determining the drying temperature is: the current value in the range of 1-10μA is determined as the drying temperature of apricot fruit leather ≥80°C, the current value in the range of 11-60μA is determined as the drying temperature of apricot fruit leather ≥60°C but <80°C, the current value in the range of 61-80μA is determined as the drying temperature of apricot fruit leather ≥40°C but <60°C, and the current value greater than 80μA is determined as the drying temperature of apricot fruit leather <40°C.

2. The method for detecting the drying temperature of apricot kernel fruit according to claim 1, characterized in that, The weight of apricot fruit leather weighed in step S1-1 is 0.5-3g, and the water is 5-20ml.

3. The method for detecting the drying temperature of apricot kernel fruit according to claim 1, characterized in that, In step S1-2, the pore size of the filter paper selected for filtration is 0.2μm-1μm.

4. The method for detecting the drying temperature of apricot kernel fruit according to claim 1, characterized in that, In step S1-3, the concentration of chitosan is 0.5-1%, and the amount added is 0.1-0.2mL.

5. The method for detecting the drying temperature of apricot kernel fruit according to claim 1, characterized in that, In step S2-1, the solution added to the surface of the gold electrode is 2-4μL.

6. The method for detecting the drying temperature of apricot kernel fruit according to claim 1, characterized in that, In step S2-2, the time of immersion in sodium hydroxide is 30s-1min.

7. The method for detecting the drying temperature of apricot kernel fruit according to claim 1, characterized in that, In step S2-3, the concentration of the phosphate buffer solution is 0.1-0.2M.

8. The method for detecting the drying temperature of apricot kernel fruit according to claim 1, characterized in that, In step S3, the concentration of hydrogen peroxide is 0.2-0.3mM.