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    Home > Chemicals Industry > Chemical Technology > Research status of rapid detection technology for edible vegetable oil

    Research status of rapid detection technology for edible vegetable oil

    • Last Update: 2022-03-18
    • Source: Internet
    • Author: User
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    (1) Routine testing methods for the quality of edible vegetable oil

    Edible vegetable oil contains essential fatty acids and fat-soluble vitamins, and is essential for human daily life


    First, use edible oil rancidity rapid detection test paper to compare whether the peroxide value and acid value of the detected oil exceed the standard;

    Second, using the relationship between the concentration of metal ions and electrical conductivity, the amount of metal ions in the oil can be judged by detecting the electrical conductivity of the oil;

    Third, use gas chromatography and liquid chromatography to identify the quality of edible oil by measuring fatty acids , triglycerides , carbohydrates and other components in edible oil


    (2) Sources and hazards of low-quality grease

    Edible vegetable oil is an indispensable cooking material in people's daily life, and it is also the main source of fat in human diet


    (1) Repeated frying oil for cooking food consumes a huge amount in the catering industry.


    (2) Inferior oils such as water and oil are used in the food and catering industry to eliminate water and oil, that is, inferior regenerated oil, which is the oil produced after processing and refining of catering waste oil or inferior pork and pig offal


    (3) Waste oil incidents are not uncommon.


    (3) The main detection methods of inferior grease

    Unsaturated fatty acids in edible oils are easily hydrolyzed and oxidized by light, oxygen, microorganisms and enzymes during storage to produce free fatty acids and hydroperoxides


    Various harmful substances that are enriched and produced by various inferior greases under harsh environmental conditions cannot be completely removed through the processing procedures, and the unqualified indicators of different processing methods will be different, and there will be different detection indicators accordingly


    1.


    (1) Acid value index The acid value of fats and oils can reflect the content of free fatty acids


    The acid value is an important indicator for the quality evaluation of edible oils, as well as a safety restriction indicator for oil products.


    (2) Peroxide value and iodine value index Peroxide is the product of the initial stage of oil rancidity, and this process occurs during the process of waste oil corruption


    (3) Carbonyl value index Carbonyl value indicates the amount of secondary decomposition products of peroxides in edible vegetable oil, that is, the amount of a series of compounds containing carbonyl groups.


    2.


    (1) Chromatography detection technology Chromatography technology, as an important method in detection technology, can also be applied to the detection of waste oil


    The chromatographic method can select many detection indicators, which can accurately and quantitatively detect trace substances with good results, but the cost of the test and the requirements for the instrument and the operator are relatively high


    (2) Spectral detection technology Spectral detection technology is a new trend of detection methods, which is fast, non-destructive, and convenient, and can better meet the needs of a large number of detection tasks
    .
    Ultraviolet-visible spectrophotometry can detect fatty acid composition, the detection speed is fast, the cost is low, but the accuracy is low, and the detection limit is large
    .
    The principle of the fluorescence analysis method is to detect the sodium dodecyl sulfonate remaining in the waste oil
    .
    This method is more sensitive and accurate, but it will be affected by the fluorescence quenching effect, and it is not suitable for the detection of old frying oil
    .

    Near-infrared spectroscopy technology mainly detects H-containing groups
    .
    Water treatment oil or deep frying oil will undergo a high degree of oxidation and rancidity during the processing process, and produce more oxidation products than ordinary vegetable fats and oils, because oxidation products will have different characteristic peaks in the near-infrared spectrum
    .
    Therefore, these characteristic peaks can be used to determine whether the edible oil contains water oil or deep frying oil.
    Scholars at home and abroad have conducted certain studies on the detection of the acid value and peroxide value of edible oil by using near-infrared spectroscopy technology
    .
    The biggest advantage of infrared analysis is that it is convenient, fast, efficient, and low-cost, which is suitable for the requirements of rapid and large-scale inspection work in the future
    .

    3.
    New rapid detection method

    (1) Foam height measurement method When the amount of polar compounds or polymers produced in frying oil exceeds the critical value, continuous foaming will occur
    .
    The foam height can be used to clearly indicate continuous foaming
    .
    By measuring the bubble height value, the carbonyl value of the frying oil can be converted to determine whether the frying oil can continue to be used
    .
    The bubble height measurement is simple and easy.
    It only needs an alcohol lamp, a thermometer and a test tube.
    The measurement can be completed within 3 minutes.
    Even if the measurement is performed 3 times in parallel, the measurement can be completed within 10 minutes
    .
    Therefore, the method of judging the quality of frying oil by the bubble height measurement method is easy to be popularized in the catering industry
    .

    (2) Dielectric property method The change of the polar components in the frying oil will cause the change of the oil's dielectric constant
    .
    Therefore, measuring the dielectric constant of the frying oil can reflect the content of polar components in the frying oil, thereby determining the hygienic quality of the frying oil
    .
    Using the principle of the dielectric property method, a portable frying oil detector has been developed that can quickly detect the degree of fat deterioration
    .
    Comparing the dielectric properties method with the routine chemical analysis method in the laboratory, it is found that the moisture content and particles in the frying oil affect the accuracy of the measurement data, and the equipment is also more expensive
    .

    (3) Scent fingerprint analysis technology The smell fingerprint analysis technology is a new technology developed for complex media and samples with synergistic effects in the past 10 years
    .
    Among them, the sensor array technology is also commonly known as the "electronic nose" technology, which is specifically designed for the analysis of odors.
    The principle and method of analysis are completely similar to the human sense of smell
    .
    Based on the sensor array response and pattern recognition technology, the electronic nose can sensitively identify odor fingerprints and their changes
    .
    Since the change of odor is usually closely connected with the change of quality, the electronic nose is an objective and reliable tool for flavor sensory detection and quality control
    .
    Research on the quality control of fats and oils using odor fingerprint analyzers has been widely carried out
    .

    Some foreign researchers have applied this technology to the detection of edible oil and have achieved certain results
    .
    Cosio et al.
    used an electronic nose system to analyze the quality of olive oil
    .
    Massa cane et al.
    laser processed olive oil samples, and then used an electronic nose system to detect and classify different olive oils
    .
    Lerma-Gar cfa and others use an electronic nose system to detect and classify olive oil and sunflower oil with different defects, and can judge the extent of the defects
    .
    Hal et al.
    used an electronic nose system to detect adulterated sesame oil and analyzed the proportion of corn oil
    .
    Cimato and others used electronic nose system, gas mass spectrometer, liquid mass spectrometer and sensory discriminant method to detect the quality of olive oil.
    The results showed that the results obtained by several detection methods were highly consistent
    .
    Martin et al.
    used an electronic nose system to classify 141 virgin olive oil and non-olive oil samples
    .
    Oliveros et al.
    used an electronic nose system to detect adulterated olive oil, and qualitatively and quantitatively analyzed the incorporated oil
    .
    James and others used electronic nose detection and recognition technology to identify virgin olive oil, ordinary olive oil and sunflower oil
    .
    Cosio et al.
    used the combination of electronic nose and electronic tongue to distinguish olive oil under different storage conditions
    .

    There are still some emerging detection methods, such as nuclear magnetic resonance, infrared or near-infrared Fourier transform method, which are used in the determination of oil quality, with stable detection results and fast detection speed
    .
    But the instrument is expensive and difficult to promote
    .

    Related link: Research progress of electronic nose in grain mildew detection

     

     

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