Food safety occurs in any country, and food adulteration is very common. Therefore, consumers are very enthusiastic about the authenticity of food. However, it is difficult to quickly distinguish the authenticity by the general food testing method. What should I do? In order to ensure the interests of consumers, the identification of food quality, especially traceability of the origin, has become the focus of food analysis technology. At the 5th International Forum on China's Food and Agricultural Products Safety Testing Technology and Quality Control held not long ago, experts in the field of food safety testing have proposed many effective methods for various endangered food fraud ( adulteration) incidents, especially The application of metabolomics in the analysis of food authenticity is generally optimistic.
Authenticity identification into hot areas
"One party raises one person in water and soil," so is everything. Affected by the region, growth environment, climate, etc., the origin of raw materials has become one of the reference factors for judging the pros and cons of food, such as Huangshan Maofeng in Anhui, Moutai in Guizhou, and Zhenjiang vinegar in Jiangsu. However, driven by huge economic interests, the falsification of the origin of food industry and the incorporation of cheap raw materials in food production have repeatedly been banned. For this reason, more and more analytical techniques are beginning to be applied to the identification of food quality and origin.
At the 5th International Forum on China's Food and Agricultural Products Safety Testing Technology and Quality Control held recently, experts in the field of food safety testing have proposed many effective methods for various endangered food fraud (adhesion) events.
For example, for the identification of the species characteristics of meat products, Shi Xiju, a researcher at the Beijing Entry-Exit Inspection and Quarantine Bureau, said that microscopic observation of microstructures, detection of nucleic acid PCR and enzymatic cleavage, and fluorescence PCR are common, and the future tends to be high-throughput and fast. Simple methods, such as LC/MS technology and test strips.
In the fields of grain fats, meat and dairy products, fermentation and nutrition, low-field NMR technology has a wide range of applications such as non-destructive, rapid, and more intuitive imaging, such as grain quality classification, grease quality testing, non-destructive testing of fruits and vegetables, Microbial fermentation monitoring, meat moisture migration, etc.
In addition, infrared spectroscopy can simultaneously measure multiple component data of a substance by simply measuring the primary infrared spectrum of the sample in tens of seconds or even seconds. It is now also used for the identification of various food adulterations. .
It is noteworthy that in recent years, high value-added imported foods such as olive oil, bee products and wine have also begun to find adulteration problems. Chen Ying, director of the Agricultural Products Safety Research Center of the China Academy of Inspection and Quarantine, said that as new food safety issues become more prominent, China's testing capacity needs to be further improved.
Chen Ying said that the previous safety inspection and identification, traceability and so on are mostly targeted screening, but the newly used compounds are not in China's standards, it is necessary to adopt non-directional screening, and in the future, it is necessary to strengthen cutting-edge technologies based on big data and multidimensional identification. Early warning and traceability studies.
Wang Zhuwei, manager of the market development department of life science analytical instrument company sciex, said at the 9th China Beijing International Food Safety Summit that conventional food analysis tests only detect target compounds and often cannot detect these adulterated foods. The new authenticity identification detection strategy should have four factors: obtaining a full spectrum that characterizes all components, data to be traceable, finding differential compounds (markers), and identifying marker components.
In his view, metabolomics technology focuses on the overall qualitative and quantitative analysis of the composition of all components of food, so the introduction of the concept of omics into food quality monitoring, including food authenticity identification and traceability analysis, will be the general trend.
Metabolomics is expected to become a weapon
As an important branch of systems biology, metabolomics is widely used in drug research, disease diagnosis, plant breeding, environmental science and other fields. "In the popular sense, metabolomics uses statistical analysis to compare differences between two or more groups of samples, to find and identify biomarkers, and to analyze metabolic pathways to reveal biological significance." Wang Zhuwei said .
“The metabolomics analyzes metabolites on a large scale, focusing on the widest range of small molecules rather than just focusing on a certain group of metabolites.†Wang Zhuwei said that metabolomics is based on a study of biological systems that are stimulated or disturbed to observe a relative molecular weight of less than 1200 Dao. Changes in small molecule metabolites or their changes over time.
Metabolomics analysis techniques can be divided into targeted metabolomics and non-targeted metabolomics, depending on the subject and purpose of the study. Known and unknown chemicals can be analyzed. It can be said that when traditional sensory index evaluation and routine quality index detection can not effectively distinguish adulterated and counterfeit food, metabolomics technology can quickly and accurately identify adulterated food.
Taking the identification of the most common red wine producing areas as an example, Wang Zhuwei said that through the mass spectrometry and spectral data generated by metabolic fingerprinting and metabolic profiling, it is possible to identify the type, source and even the vintage of the wine. The traditional method for judging the quality of grapes used for winemaking is generally to determine their sugar content, acidity, ph and total phenol content, respectively. By establishing metabolite fingerprints of mature grapes from different wine producing areas, they can be identified and some are temporarily unrecognizable. Metabolite fingerprinting of metabolite components is not possible with traditional methods.
Wang Zhuwei further stated that high-resolution accurate mass spectrometry combined with metabolomics analysis methods will also be the best means for authenticity identification and traceability analysis of beverages.
Practical application needs further study
The opinion of many experts is that the most striking feature of metabolomics is its overall analytical ability, which emphasizes the overall effect of exogenous substances on organisms, which can better reflect the environment (geography, climate, etc.). The impact of food composition. However, metabolomics does not appear to be rapidly hotter as proteomics, but presents a slowly rising trend. Wang Zhuwei said that the identification of markers is still one of the bottlenecks in the current metabolomics application.
The American Journal of Analytical Chemistry has pointed out that at present, metabolomics faces many challenges. For example, the development and growth of metabolite databases is an important issue that needs to be solved in the industry. To date, only a small fraction of all metabolites have been identified and included in the metabolite database, and most naturally occurring metabolites are still unknown.
The above article argues that people are looking forward to the tremendous advances in metabolomics, using new mass spectrometry interfaces that require little sample preparation, and the ability to analyze the metabolites of proteins at the tissue and single-cell levels using maldi imaging mass spectrometry to obtain spatial distribution of specific molecules. information. Sample preparation methods and improvements in analytical platforms, including the possibility of higher sensitivity nmr systems combined with on-line mass spectrometry, will enhance the relevance of food metabolomics research. In addition, capillary electrophoresis and capillary mass spectrometry are ideal tools for metabolomics research because they do not require extensive sample preparation, have a wide range of applications, high efficiency, high resolution, and low sample consumption.
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