Method for detecting freshness of chicken by utilizing electrochemistry
Technical Field
The invention belongs to the technical field of food detection, and particularly relates to a method for detecting freshness of chicken by utilizing electrochemistry.
Background
The chicken is a food which is eaten by people in daily life, contains a large amount of protein and a plurality of trace elements, and is popular among consumers. However, chicken is extremely susceptible to bacterial infection from slaughter to market entry. Especially fresh cut meat, is a natural culture dish for the survival and propagation of microorganisms due to its moist surface. Microorganisms accumulate on the surface of the meat for a long time, causing the meat to spoil. Deteriorated meat not only has poor taste, but also causes serious harm to human bodies, so the method has important practical value for detecting the freshness of the chicken.
At present, the traditional bacteriological inspection method and the serological method are still commonly adopted for chicken detection in China, and the two methods are complicated in steps and expensive in reagent price. In recent years, many novel detection methods such as computer vision detection, high performance liquid chromatography, nucleic acid probe detection, biochip detection, capillary electrophoresis amperometry and the like have been explored for detecting freshness of chicken meat, but most of the above detection methods still require laboratory high-precision instruments and professional personnel for operation, and have certain limitations in field detection application.
Electrochemical detection is preferred in recent years because it is relatively simple to operate compared to the aforementioned detection methods, and does not require expensive reagents or precise instruments.
For example, chinese patent CN109470746 discloses a pork freshness detection method, which detects capacitance values of standard samples with different storage times by an electrochemical sensor to obtain a standard curve for pork freshness, so as to determine the pork freshness. However, the above method requires the use of an electrochemical sensor, which is a relatively precise electrochemical instrument and is relatively expensive.
Chinese patent CN101806741B discloses a method for rapidly detecting freshness of meat and a detection platform thereof, wherein the method comprises the steps of placing meat in a closed container to collect gas, utilizing MWNTs/PVA/(pq)2Ir (N-phMA) modified electrode to have good response to inorganic ammonia, and then carrying out cyclic voltammetry-electrochemiluminescence scanning to obtain the freshness of the meat. However, the method has higher requirements on experimental operation and insufficient accuracy.
Disclosure of Invention
Aiming at the defects in the technical method, the invention aims to provide a method for detecting the freshness of chicken by using electrochemistry. The detection method has the advantages of simple operation method, sensitive reaction, low instrument cost, high speed, high accuracy and the like.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for detecting freshness of chicken by using electrochemistry comprises the following steps:
(1) sample treatment: cleaning chicken samples with different freshness in deionized water, sucking water on the surface of the chicken by absorbent paper, mincing the chicken into meat paste, weighing a certain amount of samples, adding a certain amount of solvent for ultrasonic extraction, and filtering the chicken solid-liquid mixed sample to obtain filtrate;
(2) collecting the electrochemical response spectrum of the chicken samples with different freshness: dripping a certain amount of filtrate obtained in the step (1) on the surface of a glassy carbon electrode, drying, immersing into a buffer solution, forming a three-electrode system with a platinum electrode and a silver/silver chloride electrode, and performing electrochemical response spectrum acquisition on chicken filtrate with different freshness by using a linear voltammetry scanning method;
(3) performing electrochemical scanning on a chicken sample to be detected: performing electrochemical response spectrum collection on the chicken sample with unknown freshness according to the process in the step (2);
(4) and carrying out data processing on the collected electrochemical response spectrum, extracting a characteristic value, comparing the difference of the characteristic values of the unknown freshness sample and the known freshness sample, and determining the freshness of the chicken.
Preferably, the amount of the chicken sample in the step (1) is 0.1 g-5 g.
Preferably, the solvent in step (1) may be water, ethanol or isopropanol.
Preferably, the amount of solvent added in step (1) is 10-50 mL.
Preferably, the ultrasonic extraction time of the chicken in the step (1) is 1-5 min.
Preferably, the filter paper used in the step (1) is made of polytetrafluoroethylene, and the pore size is 200 nm-2 μm.
Preferably, the chicken filtrate dripped on the surface of the glassy carbon electrode in the steps (2) and (3) is 0.5-3 muL.
Preferably, the buffer solution in steps (2) and (3) may be a phosphoric acid buffer solution, a citric acid-sodium citrate buffer solution, an acetic acid-sodium acetate buffer solution, or a barbiturate-hydrochloric acid buffer solution.
Preferably, the parameters of the linear voltammetry in steps (2) and (3) are: the scanning interval is-1.5V, the scanning speed is 50-100 mV/s, and the sampling interval is 1-5 mV.
Preferably, the concentration of the buffer solution in the steps (2) and (3) is 0.1mol/L to 0.5mol/L.
Preferably, the characteristic value of the data in the step (4) adopts the ratio of the highest peak value of the oxidation peak between-0.2V and 0.5V to the highest peak value of the oxidation peak between 0.6V and 1.2V, or adopts the ratio of the highest peak value of the oxidation peak between 0.4V and 0.8V to the highest current value in the scanning interval.
The invention adopts the ratio of the highest peak value of the oxidation peak between-0.2V and 0.5V to the highest peak value of the oxidation peak between 0.6V and 1.2V, or adopts the ratio of the highest value of the oxidation peak between 0.4V and 0.8V to the highest current value in the scanning interval as the characteristic value of data, and has the advantages of high detection accuracy, high response speed and simple data calculation.
Compared with the prior art, the invention has the beneficial effects that:
according to the chicken freshness detection method, the freshness of the chicken sample is judged and detected by the difference of potential and peak value caused by the difference of electrochemical activities of electrochemical substances in chicken due to the difference of storage time of the chicken at the same part; the chicken freshness detection method disclosed by the invention is simple to operate, sensitive in reaction and low in instrument cost, can be used for quickly and accurately detecting the freshness of chicken, and has a relatively high economic value in practical application; in addition, the following advantages are provided:
1. the method for detecting the freshness of the chicken provided by the invention has low detection cost.
2. The detection method provided by the invention has the advantages of simple steps, low requirement on inspectors and strong popularization applicability.
3. The method for detecting the freshness of the chicken by utilizing the electrochemistry can develop a portable chip type electronic scanning device, try kit formation and be used for field detection.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs.
Example 1:
the embodiment is a chicken breast, chicken wing and chicken leg freshness detection method, which comprises the following steps:
electrochemical scanning spectrum collection of different freshness of different parts of chicken
(1) Placing chicken breast, chicken wings and chicken legs stored at 5 ℃ for 0-10 days into deionized water for cleaning, and sucking water on the surface of the chicken breast by using absorbent paper;
(2) taking 1g of chicken breast meat after pretreatment, mincing the chicken breast meat into meat paste, adding 2mL of ethanol as a solvent, mixing, and performing ultrasonic treatment for 1 min;
(3) filtering the fully mixed sample by using polytetrafluoroethylene filter paper with the aperture of 200nm, taking 1 mu L of filtrate to drip-coat the surface of a glassy carbon electrode and naturally airing, inserting the modified electrode into 10mL0.1mol/L phosphoric acid buffer solution, and carrying out linear voltammetry scanning detection; wherein the scanning detection conditions are as follows: the scanning interval is-1.0V, the scanning speed is 100mV/s, and the sampling interval is 1 mV; the electrochemical response of each sample was taken 5 times. (4) The electrochemical signals obtained by scanning are subjected to standardization processing, the ratio of the highest peak value of the oxidation peak between-0.2V and 0.5V to the highest peak value of the oxidation peak between 0.6V and 1.2V is calculated, the average value of 5 times of collected data is taken, and the data is shown in the following table 1:
TABLE 1 electrochemical test data of chicken breast, chicken wings and chicken legs stored for different periods of time
For chicken samples with unknown storage time, the same method can be adopted for detection, the obtained electrochemical signals are subjected to standardization treatment, and the ratio of the highest peak value of the oxidation peak between-0.2V and 0.5V to the highest peak value of the oxidation peak between 0.6V and 1.2V is calculated, so that the freshness grades of different parts of the chicken can be evaluated. When the freshness comparison is only needed to be carried out on two or more types of chicken, the ratio is obtained by adopting the same method, and the sample with the larger ratio is not fresh.
The same method is used for carrying out electrochemical detection on the chicken breast which is stored at 5 ℃ for unknown time, the ratio of the highest peak value of the oxidation peak between-0.2V and 0.5V to the highest peak value of the oxidation peak between 0.6V and 1.2V is extracted and calculated, and the result is shown in table 2. As can be seen from table 2, the chicken breast freshness was the lowest for sample 2.
TABLE 2 electrochemical detection data of chicken breast meat stored for unknown time
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Sample 1
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Sample 2
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Sample 3
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Ratio of
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0.24
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0.61
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0.27 |
According to the embodiment, the freshness of the chicken sample is judged and detected by the method for detecting the freshness of the chicken, wherein the differences of potential and peak value are caused by different electrochemical activities of electrochemical substances in the chicken due to different storage times of the chicken at the same part; the chicken freshness detection method disclosed by the invention is simple to operate, sensitive in reaction and low in instrument cost, can be used for quickly and accurately detecting the freshness of chicken, and has a relatively high economic value in practical application.
The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core ideas. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.