The Determination Of Flavonoids In Indocalamus Leaves And Rice Dumplings With The Study Of Migration Patterns

In recent years,food containers,packaging and other materials in the migration of certain substances in food has become a hot research at home and abroad.But they mainly study the toxic and harmful substances in packaging material migration,the study on the migration of flavonoids in the packaging materials is still rare.The determination of flavonoids in indocalamus leaves and rice dumplings with the study of migration patterns are meaningful,not only fit the green concept of healthy diet,but also provide a theoretical basis for the application of traditional natural packaging materials in food.The extraction conditions and analytical methods of flavonoids in rice dumplings were optimized and compared,a method was developed for the determination of isoorientin,orientin,vitexin,isovitexin and p-coumaric acid in rice dumplings by high performance liquid chromatography(HPLC).Compared the content of flavonoids in different regions of Indocalamus leaves,probes into the effect of source of flavonoids in the dumplings and raw materials on the content.Investigated the source of flavonoids in rice dumplings.The migration pattern was established by the determination of flavonoids in indocalamus leaves and rice dumplings after the first and the second boiling and under different preservation conditions.The mainly contributions of this study include the following aspects.(1)A method for the determination of 5 flavonoids in indocalamus leaves and rice dumplings.The samples were extracted by 40%ethanol water(V/V),rotated and concentrated after centrifugation,then contented by water.The targeted compounds were separated on an Waters XBridge C18(4.6 mm×250 mm,5 ?m)column using 0.1%acetic acid water(V/V)acetonitrile:methanol = 78:9:13 as mobile phase in isocratic elution,and quantified by the matrix matched external standard method.The result indicate that using the HPLC methods,5 flavonoids showed good linearities in the range of 1.0?100.0 ?g/L and high correlation coefficents(r2>0.99).The detction limits of indocalamus leaves were in the range of 0.2-0.5 mg/kg and the quantitation limits were in the range of 0.6?1.5 mg/kg.The mean recoveries at three spiked level ranged from 67.2?125.1%.The detction limits of indocalamus leaves were in the range of 0.01?0.03 mg/kg and the quantitation limits were in the range of 0.03?0.09 mg/kg.The mean recoveries at three spiked level ranged from 65.2%?126.5%.(2)Study on the content of flavonoids in Indocalamus leaves from different regions:Isoorientin in indocalamus leaves have little difference in 5 main regions.The content of orientin,vitexin,isovitexin in indocalamus leaves producted by Zhejiang Hangzhou are much higher than others,the content of p-coumaric acid in indocalamus leaves producted by Zhejiang Hangzhou is about one fourth of the other regions.(3)Study on the migration pattern of flavonoids in rice dumplings:Indocalamus leaves were a major source of flavonoids in rice dumplings.The flavonoids were not found in the glutinous rices,which was a perfect control for migration.After the first boiling,the amount of emigration was higher from the higher of flavonoids in Indocalamus leaves.In different kinds of rice dumplings,all the stuffing could promote the emigration of orientin,isovitexin in indocalamus leaves and hinder the immigration of flavonoids into glutinous rices,except vitexin.In different preservation ways of rice dumplings,vacuum preservation is most beneficial for the immigration of vitexin,quick-frozen preservation is most beneficial for the immigration of isoorientin,orientin and p-coumaric acid.In the second boiling,the content of migration of flavonoids was large in the first 30 min.The content of emigration and the migration rates of flavonoids in 120min is about 1.3-3 times of that of the first boiling.5 flavonoids can migrate with the preservation time,the emigration of the content of flavonoids in vacuum and quick-frozen preservation rice dumplings was large in 15 days,the immigration of the content of flavonoids increased with the preservation time.The migration rates of preservation ways from fast to slow is fresh preservation,vacuum preservation,quick-frozen preservation.Isovitexin only immigrate in fresh preservation rice dumplings with boling and preservation.In short,high temperature can achieve the rapid migration of flavonoids in rice dumplings,the migration rates is slower with preservation time.