CN105181912B - A method for detecting the freshness of rice during storage - Google Patents

Abstract

The invention relates to a freshness detection method during rice storage, which belongs to the technical field of rice storage monitoring; the invention first uses a gas collection probe with a heating device and a special filter to collect volatile gases in grain storage equipment, and then utilizes The 3CCD camera acquires the R, G, and B images before and after the sensor array on the hydrophobic film reacts with the rice sample gas, and the computer processes the image, and finally substitutes the color signal value into the linear discriminant analysis model, and the computer outputs the freshness of the rice sample; The invention detects the freshness of rice by its volatile odor, which is a green, fast and non-destructive method. Compared with traditional chemical detection methods, the present invention is more convenient, non-polluting, and has a certain consistency with human sensory evaluation. Compared with artificial sensation, the present invention has better objectivity and reproducibility. The invention has important practical significance for satisfying consumers' requirements on food quality and safety and maximizing the benefits of fully utilizing raw materials of enterprises.

Description

A method for detecting the freshness of rice during storage

technical field

The invention relates to a method for detecting freshness during rice storage, and belongs to the technical field of monitoring during rice storage.

Background technique

Rice is one of the staple foods of our people. After the rice is ridged, the rice loses the protection of the rice husk, and the endosperm directly contacts with the air, and the starch, fat and protein in the rice will undergo various changes, making the rice lose its original color, aroma, taste, nutrients and nutrients. The food quality is reduced, and even toxic and harmful substances are produced. In addition, the freshness of rice will also affect the quality of its additional products. For example, the content of glycosyl compounds in beer brewed from aged rice increases, leading to the aging of beer.

At present, the detection methods of rice freshness in my country include TBA value determination method, acid-base indicator method, enzyme activity method and so on. As in GB/T15684-1995, the freshness of rice is tested by measuring fatty acids in rice, however, the method has complicated steps and poor accuracy. The invention patent "Detection Tube for Quickly Checking Freshness of Rice" (201220263903.5) discloses a test tube for quickly checking the freshness of rice, but the result is poor in accuracy and cannot be quantified when compared with the standard color card. The paper "Comparison of several methods for detecting the freshness of rice" introduces the enzyme activity method to measure the freshness of rice, but the method has complicated steps and poor accuracy, and cannot detect the freshness of rice quickly and accurately; the paper "Rice freshness "Research on Rapid Detection Technology" introduced the rice freshness measuring instrument of SATAKE company in Japan, but the imported equipment is expensive, and the samples need to be pretreated, the steps are cumbersome, and the accuracy is not high.

Therefore, finding a simple, stable, and quantifiable characterization and detection method for rice freshness has important practical significance for monitoring and testing rice quality, satisfying consumers' concerns about food quality and safety, and maximizing the full utilization of raw materials for enterprises. . Color-sensitive sensor technology is a new method of gas characterization that has emerged in recent years. It uses the color difference before and after the reaction between the color-sensitive sensor and the gas to be measured to conduct qualitative and quantitative analysis of the gas to be measured. In recent years, color-sensitive sensor technology has been used in food and the field of agricultural product detection have been related applications, such as the patent "a method and device for detecting fish freshness based on olfactory visualization" (application number: 201010262347.50) discloses a method and device for olfactory visual detection of fish freshness, but the device It is relatively heavy, and its image acquisition device is a scanner, which is difficult to meet the requirements of real-time monitoring. Color-sensitive sensor technology has its unique advantages in the detection of agricultural product odor, but the freshness detection in the process of rice storage has not been reported.

Contents of the invention

The purpose of the present invention is to overcome the deficiency of the freshness detection method in the existing rice storage process, propose a kind of freshness detection method of the rice storage process based on novel color-sensitive sensor technology, monitor the whole rice storage process automatically and in real time through the wireless sensor array Changes in freshness.

The technical solution adopted in the present invention is as follows:

The invention provides a freshness detection device during rice storage, which includes a computer, an information collection system, a vacuum pump, a heating module, a gas collection probe with a special filter screen and rice storage equipment.

The information collection system includes a 3CCD camera, LED light source, reaction chamber and sensor array, wherein the 3CCD camera is fixed on the upper end of the information collection system and connected to the computer. The 3CCD camera is used to obtain the red (R) of the sensor before and after the reaction. , green (G), and blue (B) images; the computer is used to process the collected volatile gas information during rice storage in real time, and the information collection system is used to collect rice volatile gas information and transmit it to the computer;

The LED light source is fixed on both sides inside the information collection system, which is used to provide a good light source guarantee for the collection of the 3CCD camera head, improve the quality of the collected image, and transmit it to the computer for real-time processing in the later stage;

A reaction chamber is arranged at the bottom of the information collection system, and a sensor array is arranged in the reaction chamber; the reaction chamber is a container for fully reacting the volatile gas in the rice storage process with the corresponding color-sensitive sensor, and the sensor array is first formed by micro-spotting 4×3 array;

The vacuum pump is connected with a gas collection probe with a special filter screen, the gas collection probe inlet is equipped with a filter screen, and the lower end is equipped with a heating module, and the gas collection probe will collect the volatility of the rice during storage The gas is pumped into the reaction chamber through a vacuum pump; the gas collection probe with a special filter is directly placed in the rice storage equipment; the function of the gas collection probe with a special filter is to prevent impurities in the rice from clogging the device, and Only volatile gases from rice during storage are extracted.

The heating module is placed in the rice storage equipment, which can be any device used for heating, and is used to detect the heating of the sample and promote the volatilization of gas.

Another object of the present invention is to provide a method for detecting the freshness of rice during storage, comprising the steps of:

(1) Firstly, the characteristic volatile gases of rice with different freshness were determined by gas chromatography-mass spectrometry (GC-MS). The change is obvious in the process (octa(ethylene glycol)-(dodecyl) ether is stored in rice for six months, the content decreases sharply; benzaldehyde does not exist in fresh rice, and as the storage time of rice increases, the content gradually increases , the content of hexanal increases first and then decreases during the storage of rice); then screen the color-sensitive materials sensitive to these gases: 3 porphyrin compounds and 1 pH indicator; among them, the 3 porphyrin compounds are Protoporphyrin dimethyl ester, octaethylporphyrin, tetraphenylbenzo ternary porphyrin, the porphyrin compounds are respectively dissolved in dichloromethane solvent, the concentration range is 1-2mg/mL, at this concentration , the color of the porphyrin solution is moderate, and it is more evenly dispersed on the medium substrate, and it is easy to react with the volatile gas of rice; the pH indicator Nile red is soluble in ethanol, and the concentration is 1-2mg/mL. , the color of the porphyrin solution is moderate, and it is more evenly dispersed on the medium substrate, and it is easy to react with the volatile gas of rice. Four kinds of color-sensitive materials were printed and dyed on the polyvinylidene fluoride (PVDF) film one by one through micro-spotting capillary tubes to make four kinds of color-sensitive sensors, and these four kinds of color-sensitive sensors constituted a color-sensitive material sensor array;

(2) The 3CCD camera acquires the initial R, G, and B images of the sensor array before the reaction and transmits them to the computer, and the computer performs image processing to obtain the initial color information;

(3) Collection of rice volatile gas at different stages: the gas collection probe is placed in the rice sample, the heating module and vacuum pump are turned on, and the volatile gas during rice storage is extracted into the reaction chamber to react with the color-sensitive material of the sensor array; 3CCD The R, G, and B images of the sensor array after the camera captures the reaction are transmitted to the computer, and the computer performs image processing, denoising through image Gaussian filtering, threshold segmentation, morphological processing, and feature region extraction (with the center of gravity of the color-sensitive material as the dot, 15 pixels as the radius of the circle) etc. to obtain the average value of the R, G, and B gray levels of each color-sensitive material in the image before and after the reaction, and obtain the characteristic matrix of the volatile gases of rice with different freshness;

(4) Use the color-sensitive material sensor array to react with the volatile gas of the sample, extract relevant information, and input the established freshness linear discriminant model to realize the detection of the freshness of the sample to be tested; the establishment of the freshness linear discriminant model, The specific operation is to conduct principal component analysis on the data, and finally select the first seven principal components to construct a linear discriminant analysis model to determine the freshness of rice.

Beneficial effects of the present invention:

1. The invention is quick and easy to operate, and is a green, fast and non-destructive rice freshness detection method. It only takes a few minutes to detect a sample, and can be used for the quality detection of aged rice, and can also be used for the aging process of rice storage. monitor;

2. Compared with traditional chemical and biological detection methods, the present invention is more convenient, pollution-free, and does not require pretreatment. Since it is a matrix composed of multiple color-sensitive sensors, it has certain consistency with human sensory evaluation and can better reflect and reflect people's evaluation and preferences for food;

3. Compared with artificial sensory evaluation, the present invention has better objectivity and reproducibility, so that the quality of rice can be memorized and inherited, and it is not easily disturbed by environmental factors and other subjective and objective factors.

Description of drawings

Figure 1 is a schematic diagram of the freshness detection system in the grain storage process.

Fig. 2 Schematic diagram of the olfactory visualization software processing system.

In the figure: 1. computer, 2. 3CCD camera, 3. LED light source, 4. reaction chamber, 5. sensor array, 6. vacuum pump, 7. gas collection probe, 8. filter screen, 9. heating module, 10. Rice storage equipment.

detailed description

The technical solutions of the present invention will be further described below in conjunction with specific embodiments and accompanying drawings.

Embodiment 1: A kind of freshness detection device in the rice storage process

As shown in Fig. 1, a kind of freshness detection device in the rice storage process provided by the present invention comprises computer 1, information collection system, vacuum pump 6, heating module 9, gas collection probe 7 with characteristic filter screen 8 and Rice storage equipment 10 .

Wherein the information collection system comprises 3CCD camera 2, LED light source 3, reaction chamber 4 and sensor array 5, wherein said 3CCD camera 2 is fixed on the upper end of the information collection system, is connected with computer 1, and 3CCD camera 2 is used to obtain before reaction, The images of red (R), green (G) and blue (B) components of the rear sensor; among them, the computer 1 is used to process the collected volatile gas information in the rice storage process in real time, and the information collection system is used to Collect rice volatile gas information and transmit it to computer 1;

The LED light source 3 is fixed on both sides inside the information collection system, and is used to provide a good light source guarantee for the collection of the 3CCD camera 2 cameras, improve the quality of the collected images, and transmit them to the computer 1 for real-time processing at a later stage;

The bottom of the information collection system is provided with a reaction chamber 4, and a sensor array 5 is arranged in the reaction chamber 4; the reaction chamber 4 is a container for fully reacting the volatile gas in the rice storage process with the corresponding color-sensitive sensor, and the sensor array 5 is first 4×3 array formed by micro spotting;

Described vacuum pump 6 is connected with the gas collection probe 7 that has characteristic filter screen 8, and gas collection probe sampling port is equipped with filter screen 8, and heating module 9 is housed at the lower end, and gas collection probe 7 will collect the rice The volatile gas in the storage process is pumped into the reaction chamber 4; the gas collection probe 7 with a special filter is directly placed in the rice storage device 10; the function of the gas collection probe 7 with a special filter is to prevent Impurities in the rice block the device, and only the volatile gases of the rice during storage are extracted.

The heating module 9 is placed in the rice storage equipment 10, and can be any device used for heating, which is used to detect the heating of the sample and promote the volatilization of gas.

Embodiment 2: a kind of detection method of freshness in rice storage process

A method for detecting the freshness of rice during storage, comprising the steps of:

(1) The samples of the implementation examples are all from the same variety of rice, and all samples are divided into four groups according to the storage time, which are 1 month, 2 months, 6 months and 12 months. Each group has 30 samples, a total of 120 samples;

(2) Production of color-sensitive sensor: A solution made of 3 porphyrin compounds and 1 pH indicator sensitive to the freshness of rice is printed and dyed on a polyvinylidene fluoride (PVDF) film through a micro-spotting capillary. On the above, a sensor array of color-sensitive materials was made, among which, 3 kinds of porphyrin compounds: ① dimethyl protoporphyrin, ② octaethyl porphyrin, ③ tetraphenylbenzo ternary porphyrin, respectively dissolved in dichloro In methane solvent, the concentration range is 1-2mg/mL (pre-optimized); pH indicator: Nile Red, dissolved in ethanol, the concentration range is 1-2mg/mL (pre-optimized);

(3) Put the sensor array 5 in the reaction chamber 4, and the 3CCD camera 2 acquires the initial images of the three color channels of the sensor array R, G, and B before the reaction;

(4) The gas collection probe 7 is placed in the rice sample, the heating module 9 and the vacuum pump 6 are turned on, and the volatile gas in the rice storage process is extracted into the reaction chamber 4 to react with the color-sensitive material; the 3CCD camera acquires the R of the sensor array after the reaction , G, and B images are transmitted to the computer, and computer 1 performs image processing, denoising through image Gaussian filtering, threshold segmentation, morphological processing, and feature area extraction (with the center of gravity of the color-sensitive material as a dot and a circle with a radius of 15 pixels) Obtain the average value of the R, G, and B gray levels of each color-sensitive material in the image before and after the reaction, and then subtract the average value of the gray level before and after the reaction to obtain the response characteristic matrix of the visual sensor array, and then restore the characteristic matrix to the image ( Figure 2). The data were subjected to principal component analysis, and the first seven principal components were extracted to construct a linear discriminant analysis model to judge the freshness of rice.

(5) Using 40 independent samples (10 samples for each category) to verify the method, the results are shown in Table 1. The results show that the comprehensive recognition rate of all samples reached 85%. However, for storage 6 The identification rate of rice samples stored for 12 months and 12 months was 100%. It shows that the method can intelligently identify the freshness of rice.

Table 1 LDA model predicts rice freshness

Claims (5)

1. a detection method of freshness in the rice storage process, it is characterized in that, described method is to utilize color-sensitive material and the rice smell reaction color difference of different freshness to distinguish the freshness of rice, and described method is based on a kind of rice A freshness detection device during storage, the device includes a computer (1), an information collection system, a vacuum pump (6), a heating module (9), and a gas collection probe (7) with a special filter (8); Among them, the computer (1) is used to process the collected volatile gas information in the rice storage process in real time, and the information collection system is used to collect the rice volatile gas information and transmit it to the computer (1); the bottom of the information collection system is provided with A reaction chamber 4, a sensor array 5 is arranged in the reaction chamber 4; The vacuum pump (6) is connected to the gas collection probe (7) with a special filter (8), the inlet of the gas collection probe is equipped with a filter (8), and the lower end is equipped with a heating module (9), The heating module (9) is placed in the rice storage device (10); The detection method mainly includes the following steps: (1) First determine the characteristic volatile gases of rice with different freshness by GC-MS, and then screen the color-sensitive materials sensitive to these gases to make a color-sensitive material sensor array; (2) The 3CCD camera (2) acquires the initial R, G, and B images of the sensor array before the reaction and transmits them to the computer (1), and the computer (1) performs image processing to obtain the initial color information; (3) Collect rice volatile gases at different stages, and transmit the collected information to the computer (1) Perform image processing to obtain the characteristic matrix of rice volatile gases with different freshness; (4) Use the color-sensitive material sensor array (5) to react with the volatile gas of the sample, extract relevant information, and input the established freshness linear discriminant model to realize the detection of the freshness of the sample to be tested; The characteristic volatile gases of rice with different freshness determined by GC-MS described in step (1) are octa(ethylene glycol)-(dodecyl) ether, benzaldehyde, hexanal; The color-sensitive material described in step (1) is three kinds of porphyrin compounds and one pH indicator; wherein, the three kinds of porphyrin compounds are protoporphyrin dimethyl ester, octaethylporphyrin, tetraphenyl Benzoternary porphyrin, the porphyrin compounds are dissolved in dichloromethane solvent, the concentration range is 1-2mg/mL; the pH indicator is Nile red, dissolved in ethanol, the concentration is 1-2mg/mL mL, each color-sensitive material is printed and dyed on the polyvinylidene fluoride (PVDF) film one by one through a micro-spotting capillary to make a color-sensitive material sensor array. 2. A method for detecting the freshness of rice during storage according to claim 1, characterized in that the specific operations of collecting volatile gases from rice at different stages in step (3) are as follows: The gas collection probe (7) is placed in the rice sample, the heating module (9) and the vacuum pump (6) are turned on, and the volatile gas during the rice storage process is extracted into the reaction chamber (4) and the color-sensitive material of the sensor array (5) Response; 3CCD camera (2) transmits the R, G, B images of the sensor array (5) to the computer (1) after acquiring the reaction, and the computer (1) performs image processing. 3. The method for detecting the freshness of a kind of rice during storage according to claim 1, characterized in that, the specific method for performing image processing by the computer described in step (2) or (3) is: The collected image information is denoised by Gaussian filtering, threshold segmentation, morphological processing, and feature region extraction. The center of gravity of the color-sensitive material is used as a dot and the radius of 15 pixels is a circle to obtain the R of each color-sensitive material in the image before and after the reaction. , G, and B gray values to obtain the characteristic matrix of volatile gases in rice with different freshness. 4. The method for detecting the freshness of rice during storage according to claim 2, wherein a heating module (9) is installed at the lower end of the gas collection probe (7) for detecting the heating of the sample , to promote gas volatilization, the inlet of the gas collection probe (7) is equipped with a filter screen (8), which is used to prevent the impurity in the rice from clogging the device, and only extracts the volatile gas of the rice during storage. 5. The method for detecting the freshness of rice during storage according to claim 2, wherein the establishment of the freshness linear discriminant model in step (4) is performed by performing principal component analysis on the data , and finally select the first 7 principal components to build a linear discriminant analysis model to judge the freshness of rice.