Screening And Analytical Technology Of Exogenous Additives In Food Stuffs

The safety of exogenous additives was a significant part of food safety. The use of food additives became an important feature of modernization with the development of food industry. Otherwise, a few of food safety incidents occurred because of the abuse of food additives and illegal additives, which had a negative influence to the human healthy and the stability of society.At present, a standard analytical method was usually fit for the detection of several targeted compounds and was difficult to determine multi-additives at the same time. Then it was necessary to establish an analytical method of exogenous additives to screen and warn the addition of food additives and potential illegal additives in food stuffs.This paper developed the screening and analytical technology taking the exogenous additives as study object by multi analysis methods. The main research contents and results were as follows:1. A method of sequential extraction and purification coupled with high performance liquid chromatography (HPLC) by multi-wavelength detection applied for the analysis of 46 synthetic pigments and dyes in food was established. The system of sequential extraction was composed of three grades. In the first grade of extraction, the Sudan dyes were extracted with n-hexane and purified effectively by Gel Permeation Chromatography (GPC). The recoveries of 8 Sudan dyes were not less than 80%. In the second grade of extraction, most of water-solution synthetic pigments were extracted with water assisted by acetonitrile. And the recoveries were not less than 60%. In the third grade of extraction, a few of compounds were extracted using methanol and ammonia water whose concentration was 1.0%. And the recoveries were not less than 55%. It was unnecessary to clean up the extract after the second and third grade of extraction. The detection results of samples from markets showed that the system of sequential extraction and cleaning was suitability for the food stuffs contained protein and fat. 2. A method of screening and determination Sudan dyes in margarine by high performance liquid chromatography/quadruple time-of-flight mass spectrometry (HPLC/Q-TOF) was established. The compounds were extracted by n-hexane and purified by GPC. The limit of detection of 8 kinds of Sudan dyes was between 0.75 ng/mL - 5 ng/mL analyzed by HPLC/Q-TOF.8 kinds of Sudan dyes were matched and identified by the function of precision mass searching and the mass spectrum library searching. The results displayed that the matching scores of all of dyes were high than 94%except Sudan red G. Then the compounds were confirmed by the Q-TOF mass spectrum.3. A screening method of 29 forbidden and limited synthetic pigments was established by HPLC/Q-TOF in cheese samples. The pigments were extracted by n-hexane-water (3:1, V/V), acetonitrile, ammonia water-methanol (1:99, V/V) sequentially and purified by GPC. The results shown that 29 synthetic pigments with a wide range of polarity were extracted effectively whose recoveries were between 70 %-95%, and matched good by the function of precision mass searching and the mass spectrum library searching whose match scores were between 60-99.5. The quantitative analysis of 29 compounds was carried on by mode of Target MS/MS. The limit of detection (LOD) of 8 Sudan dyes were between 0.4 ng/g and 2.5 ng/g while the LOD of 21 water-soluble synthetic pigments were between 0.02 mg//kg-0.10 mg/kg. The screening method was suitable for a wide range of polarity and the food stuff with the similar matrix.4. The synthetic colorants in meat products were screened by the sequential extraction and purification coupled with HPLC/Q-TOF. Allura red was found by this screening method. Then a determination of allura red in meat products by solid phase extraction with bonded Si-Chitosan as sorbent and liquid chromatography tandem mass spectrometry was established. Meat products were extracted by ethanol-ammonia water and the fat component was removed by n-hexane. Then the extraction solution was purified by solid phase extraction (SPE) with bonded Si-Chitosan as adsorption materials. The SPE conditions were optimized and the results as follows:the mass of bonded Si-Chitosan was 0.25 g, the washing solvent was 6 mL of methanol and the elution solvent was 8 mL of 2%ammonia water-methanol. The recoveries of analysis were higher than 70%, and the relative standard deviation (RSD) was between 3%to 7%.5. A screening method of food additives and their potential cooking decomposition compounds was established in prawn crackers. As target additives, tartrazine, ponceau 4R, sunset yellow and brilliant blue were detected by HPLC/Q-TOF. As non-targeted additives, benzoic acid and 2,5-Di-tert-butylhydroquinone (BHQ) were found by this screening method. TBHQ and its oxidation product 2-tert-Butyl-l,4-benzoquinone were found by GC/MS. Prawn cracker samples were treated with microwave and were fried by edible oil respectively. And the chromatograms of them were compared with untreated samples using HPLC/Q-TOF. The results showed that there were no typical suspicious substances originated from additives during the cooking process. And the effectiveness of the screening system reflected that it was suitable to detect, analyze, screen and confirm food additives and suspicious compounds in food matrix.