Application of Synthetic Coloring Agent in Food and Research Progress of Analytical Technology

Abstract: This article mainly introduces the variety, scope of use and limit of use of synthetic colorants, as well as the pre-processing technology, detection technology, scope of application and testing items in the analysis technology, and the direction of the future analysis technology standards for synthetic colorants in food The development is looking forward
.

Keywords: synthetic colorants; food; research progress; analytical technology; application of
synthetic colorants refers to organic pigments made by artificial chemical synthesis methods, because of their bright colors, strong coloring power, good stability, and low production costs.
It is widely used in the food industry, but in order to improve the sensory color and luster of food, some manufacturers use synthetic colorants in excess of the limit and range
.
The national food safety supervision and random inspections announced in 2020 show that the problem of using synthetic colorants beyond the scope and limit still exists
.
Long-term consumption of a large number of foods with unqualified synthetic colorants may have certain effects on the human liver [1-2]
.

In recent years, as consumers have increased their awareness of food safety and healthy eating, foods that use synthetic colorants in excess of the limit and range have received more and more attention from consumers and supervisors
.
This article mainly analyzes the application and analysis technology of synthetic colorants in food
.

1 synthetic coloring agents in food applications
add our synthetic colorants in food has a strict limit, "national food safety standards of food additives using standard" (GB 2760-2014) [3] are allowed to use synthetic coloring agents, 11 Species, respectively, lemon yellow, sunset yellow, quinoline yellow, new red, amaranth, carmine, allure red, erythrosine, acid red, brilliant blue and indigo, and the allowed food category and maximum use amount It is clearly stipulated that this article mainly summarizes the application categories of synthetic colorants in food from the secondary classification, see Table 1 for details
.
The 11 kinds of synthetic colorants allowed to be added to food basically cover 12 categories of food substrates, namely: milk and dairy products; frozen drinks; cocoa products, chocolate and chocolate products (including cocoa butter substitute chocolate and products), and candy ; Fruits, vegetables (including roots), beans, edible fungi, algae, nuts and seeds, etc.
; grains and food products, including rice, flour, whole grains, root plants, beans and corn starch, etc.
(not including Baked products); Baked foods; Meat and meat products; Sweeteners, including honey; Condiments; Beverages; Wines; Others
.
Adding synthetic coloring agents to foods is mainly used to improve the sensory properties of foods
.

2 Analytical techniques
for synthetic colorants in foods.
The standards for the detection of synthetic colorants in foods include "National Food Safety Standard Determination of Synthetic Colorants in Food" (GB 5009.
35—2016), "National Food Safety Standard Determination of Allure Red in Food" (GB 5009.
141-2016), "Detection of Allure Red, Acid Red, Brilliant Blue, Sunset Yellow Content in Food" (SN/T 1743-2006), "Determination of Carmine Coloring Agent in Meat Products" (GB/T 9695.
6-2008 ), "High Performance Liquid Chromatography Method for the Determination of Synthetic Colorants in Canned Fruits" (GB/T 21916—2008) and "Liquid Chromatography Method for the Determination of 11 Synthetic Colorants in Exported Beverages, Ice Cream and Other Foods" (SN/T 4457—2016), the main pretreatment technologies are polyamide adsorption, liquid-liquid extraction, solid-phase extraction, membrane filtration and ultrasonic extraction, all of which use the principle of good solubility of food synthetic colorants in water, according to the characteristics of the matrix of each method Perform pre-processing
.
The analysis techniques are mainly high performance liquid chromatography, paper chromatography and colorimetry, as shown in Table 2 [4-9]
.
Based on the different sample matrix and test items in each standard, the principle of each standard detection method is also different
.
The principle of "National Food Safety Standard Determination of Synthetic Colorants in Food" (GB 5009.
35—2016) is that synthetic colorants in food are extracted by polyamide adsorption method or liquid-liquid partition method, made into aqueous solution, and injected into high performance liquid chromatography.
The instrument was separated by reversed-phase chromatography and quantified according to the retention time qualitatively and compared with the peak area
.
The principle of "National Food Safety Standard Determination of Allure Red in Food" (GB 5009.
141-2016) is that Allure Red is adsorbed by polyamide powder under acidic conditions, and desorbed under alkaline conditions, and then separated by paper chromatography.
Qualitative and quantitative spectrophotometry
.
The principle of "Detection of Allure Red, Acid Red, Brilliant Blue, and Sunset Yellow in Foods by High Performance Liquid Chromatography" (SN/T 1743—2006) is to extract synthetic colorants in candies and beverages by polyamide adsorption.
After filtration, reversed-phase high performance liquid chromatography was used for separation and determination, and external standard method was used for quantification
.
The principle of high performance liquid chromatography in "Determination of Carmine Coloring Agent in Meat Products" (GB/T 9695.
6—2008) is that the carmine in the sample is defatted by the sample, extracted with alkaline solution, precipitated protein, and absorbed by polyamide powder.
After absolute ethanol+ammonia+hydrolysis and absorption, it is made into an aqueous solution, filtered and measured by high performance liquid chromatography, qualitatively based on retention time, and quantified by external standard method
.
The principle of the colorimetric method is that the carmine in the sample is degreasing, extracted with alkaline solution, precipitated protein, absorbed by polyamide powder, dehydrated ethanol + ammonia + hydrolyzed and absorbed, and then made into an aqueous solution, filtered by spectrophotometry The absorbance was measured with a meter, and the external standard method was used for quantification
.
The principle of "Determination of Synthetic Colorants in Canned Fruits by High Performance Liquid Chromatography" (GB/T 21916—2008) is that the synthetic colorants in canned fruits are extracted with ethanol-ammonia water, purified by solid phase extraction column, and high-efficiency liquid Measured by gas chromatography-diode array detector and quantified by external standard method
.
The principle of "Liquid Chromatography Method for the Detection of 11 Synthetic Colorants in Exported Beverages, Ice Cream and Other Foods" (SN/T 4457-2016) is that the sample is ultrasonically extracted with 5% acetonitrile aqueous solution and measured by liquid chromatograph with external standard Quantitative
.
Among them, the most commonly used detection technique is high-performance liquid chromatography, which mostly uses retention time qualitative and external standard method for quantification
.
It is widely used because of its fast analysis speed, good repeatability and high quantitative accuracy .
However, these analysis techniques uncovered "Food Safety Standard food additive synthesis using standard colorant" (GB 2760-2014) can be added to all food categories, e.
g.
spices, vegetable products, starch products, nuts and seeds, frozen drinks , grain and grain products, baked goods and soy products and so on
.

3 Conclusion The
"National Food Safety Standard Food Additives Use Standard" (GB 2760-2014) clearly stipulates the types, scope and limits of use of synthetic colorants that are allowed to be used
.
At present, there are many studies on certain categories of certain synthetic colorants, but they fail to meet all the use categories of the "National Food Safety Standards for the Use of Food Additives" (GB 2760-2014)
.
It is recommended that 11 synthetic colorants of lemon yellow, sunset yellow, quinoline yellow, new red, amaranth, carmine, allure red, erythrosine, acid red, brilliant blue and indigo are simultaneously tested and covered in the National Food Safety Standard For all use categories of Food Additives Standard (GB 2760—2014), common solid-phase extraction pretreatment technology combined with high performance liquid chromatography analysis technology is used to conduct related research to improve the convenience and operability of the detection method, so that In the National Food Safety Standard Food Additives Use Standard (GB 2760—2014), foods with synthetic colorants added have corresponding testing method standards and supporting them
.

References
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