Studies On Active Ingredients And Safety Evaluation Of Quality In Garlic

Garlic has many nutrition and health benefits of the human. The content ofsulfur-containing active ingredients and pesticide residues are measured as theimportant indices for quality and safety of garlic and its products. It is essential thatappropriate methods used in the determination of the organosulphur compounds(thiosulfinate, thioether, etc.) be set up and the matrix effect used in thedetermination of pesticide residues be optimized in garlic and its products. The fast,practical and accurate methods will have a positive impact on the deep processingand multi-function development of garlic.The main content of this thesis is as follows:1. An analytical method was described for the quantitative determination of allicin(diallyl thiosulfinate) in fresh garlic sample, using reversed-phase HPLC with UVdetection. Discussed the effects of extraction solvent, extraction temperature,extraction means, extraction times and solid-liquid ratio, optimum pretreatmentcondition was obtained that added amount of100mL water in3g of garlic sampleand extracted only one times at room temperature. Fresh garlic test of averagerecovery were95.5~106%and the relative standard deviation(RSD) value were1.4~2.8%among the three standard added levels (every level repeated three times).Linearity between the allicin concentration and the peak area was good within theconcentration ranges from10.0to500μg/mL, R2was0.9998, and the detection limitwas167mg/kg. The results showed that the method described here was obviousadvantages for the determination of allicin in garlic, such as simple samplepretreatment, quantitative accuracy.2. An analytical method was established for the quantitative determination ofdiallyl disulfide(DADS) and diallyl trisulfide(DATS) in garlic powder sample, usingreversed-phase HPLC with UV detection. Linearity between the DADS and DATSconcentration and the peak area was good within the concentration ranges from5.00to100μg/mL. R2were respectively0.9989and0.9993. The detection limit wasrespectively158mg/kg and107mg/kg. DADS of average recovery were90.9~98.2% and RSD≤3.5%and DATS of average recovery were103~106%and RSD≤4.8%among the three different standard concentrations added levels (every level repeatedthree times). The accuracy and precision of such method were satisfactory. For allabove these it was showed that the method has satisfactory accuracy and precision.3. The last section，matrix effect of39different kinds pesticides in garlic werestudied by UPLC-MS/MS, which used three different matrices purification methods(acetonitrile extraction, QuEChERS, solid phase extraction small columnpurification). According to the evaluating method of matrix effect, the EconomouAnastasios put forward to, QuEChERS purification was demonstrated to be enoughto eliminate most of the matrix effect except for the three carbamate pesticides(Carbaryl, Tsumacide, Methomyl). The research provided reference for the rapid andaccurate determination of pesticides residue in sour spicy vegetables such as garlicby LC-MS/MS.