| The fern root is the root of a perennial herb in the family Pteridaceae named fern[Pteridium aquilinum var.Latiusculum(Desv.)Underw].The root of fern is crushed,and added with sweet potato starch,cassava starch,potato starch and corn starch,of which dried product is called fern root vermicelli.The fern root vermicelli is rich in starch,and contains plant proteins,oligosaccharides,amino acids and calcium,iron,zinc,selenium,and other essential trace elements for human bodies,which is a characteristic folk food in southern Shaanxi,Sichuan,Guizhou and other places.However,the presence of ptaquiloside and metal aluminum in fern root vermicelli has always troubled the industry development of fern root vermicelli.Ptaquiloside is at risk of carcinogenesis,which distributed in all parts of the fern,with some residues in the fern root vermicelli.The aluminum content in fern root vermicelli was high,which exceeded the upper limit of national food safety standard,producing substandard products easily.In order to ensure the product quality and food safety of fern root vermicelli,reduce the carcinogenic risk of fern root vermicelli,effectively control the content of aluminum in the product,it is necessary to carry out the accurate and effective detection of ptaquiloside and aluminum in fern root vermicelli,and to remove the ptaquiloside by optimizing the process,which provides the analysis and detection technology guarantee and theoretical study basis for the analysis and evaluation of the quality of fern root vermicelli,the risk control of food safety and the formulation of related product standards,and promoting the healthy and orderly development of fern root vermicelli industry.Specific research contents can be mainly divided into the following aspects.(1)Three methods were used to simultaneously determine aluminum content in fern root vermicelli.The results of methodological verification showed that the precision,stability and repeatability of Aluminum-spectrophotometry met the requirements of methodology,but the recovery rate was much higher than 105%,and the reagents were complicated.The content RSD of the precision,stability and repeatability of Aluminum-AAS were much higher than 5,the average recovery rate exceeded the requirement,and the linear range was narrow,and thus,this analytical method is not ideal.The Aluminum-inductively coupled plasma mass spectrometry shows the good linear relationship in a linear range,with the correlation coefficient is 0.9997,and the detection limit of which is 0.44 mg/kg,and the quantitative limit of which is 1.48 mg/kg,with the wide linear range,the precision,stability repeatability andrecovery of which meet all the methodological requirements,and this method is efficient,accurate and with less interference,suitable for the determination of aluminum in fern root vermicelli.The content of aluminum in fern root vermicelli was detected to be in the range of107.21 ~ 251.91 mg/kg.(2)A indirect determination method was developed using UPLC-MS-MS/MS to simultaneously determining ptaquiloside(PTA)in the fern root vermicelli.The pterosin B(PTB)in sample was extracted with 50% methanol,using Waters ACQUITY UPLCTMBEH C18 chromatographic column and Mass spectrometry was conducted by using positive(ESI+)electrospray ionization and Multi-reactions monitoring(MRM)models,with PTB external standard method,through being completely transformed into PTB from PTA by the transformation treatment,the PTA content was indirectly obtained by the formula calculation.The flow rate of Chromatographic system was 250 ?L/min and at 35 ?.The mobile phase of acetonitrile was 0.1% methanoic acid and acetonitrile,with gradient elution.Validated by methodology,the results showed that,the PTA shows a good linear relationship in the range of 0.91 ?g/ml ~ 9.12 ?g/ml,and the correlation coefficient is greater than 0.9999.The precision,stability and repeatability of this method are good,and the average recovery of which was 100.30%(n=6),RSD <5%.The detection limit of this method was 18.25 ng/mL,and the quantitative limit of which was 91.26 ng/mL.The content of ptaquiloside in the fern root vermicelli was detected in the range of 97.72 ~ 116.99 mg/kg.The method can efficiently detect the content of ptaquiloside in fern root vermicelli,reasonably analyze the quality of fern root powder,and effectively control the production quality of fern root vermicelli.(3)Using UPLC-MS-MS to detect PTA,with the peak area of PTA as an index,the effects of four factors such as the ratio of material to liquid,temperature,reaction time and pH value,on the removal of procyanidin were investigated.On the basis of single factor experiment,the removal process of PTA in the fern root vermicelli was optimized by using the response surface.The optimum conditions were as follows: the ratio of liquid to material was 50.00:1,the water bath time was 35.04 min,the water bath temperature was 60.00 ?,the pH value was 9.8,and the maximum yield was 90.29%.The samples were prepared under optimized conditions and the yield of tea polyphenols detecting and calculating by ultra performance liquid chromatography and mass spectrometry was 90.37%.The results showed that the removal process and conditions of PTA was feasible,and combined the detection with UPLC-MS-MS,which could be used to qualitatively and quantitatively analyze PTA in the fern root vermicelli. |
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