Separation And Determination Of The Flavor Peptides And Characteristic Components In Neoboletus Magnificus

The wild edible mushrooms are famous for their delicious taste,varies of nutrition such as proteins,vitamins and mineral elements,and also the biological activity such as enhance the immune system,reduce blood lipids as well as regulate endocrine.Neoboletus magnificus distributes in southwest China,is one of numerous Yunnan wild edible mushrooms,its unique smell and delicious taste make it popular among the customers.The flavor of wild edible mushrooms consists of not only abundant free amino acids,soluble sugar,organic acids,but also the small flavor peptide that have been always forgotten;Ergosterol,an important plant sterol,can be converted into vitamin D₂ when exposed to ultraviolet light,and abounds in Neoboletus magnificus,but its content is susceptible to drying method.This paper focus on the preparing,separation,purification and identification of the flavor peptides from Neoboletus magnificus in order to expound the composition of the flavor compounds and their contributions to the flavor as well as the effect of different drying methods on the content of ergosterol existing in Neoboletus magnificus.The main research contents and results in this paper are as follows:1.Separation and purification of flavor peptides in Neoboletus magnificusWe explore the optimum water extraction condition of Neoboletus magnificus and purified the flavor peptides exist in it.The optimum water extraction condition with highest peptide content is under 45?for 2 hours with the solid-liquid ratio 1:4.Five fractions,namely fraction?,?,?,?and?,are separated by gel chromatography column.After sensory evaluation,fraction?with the highest umami score were chosen to be purified by RP-HPLC,and five peaks are found,namely P1^P5.P3 has the higher taste dilute value as well as umami taste,so it was selected for further identification using MS and peptides with sequences of Ser-Gly-Pro-Val-Gly-Glu-Arg?Arg-Asp-Glu-Ala-Ser-Val-Leu-Arg and Val-Trp-Asp-Ser-Ser-Glu-Ser-Leu-Arg was identified.2.Determination of Ergosterol in Neoboletus magnificus under Different DryingMethodsIron magnetic nanoparticles assembled with octadecyltrimethoxysilane?ODTMS?are used as an adsorbent for magnetic dispersive solid phase extraction?MDSPE?.The content of ergosterol in N.magnificus treated with different drying methods were determined by HPLC.The principal influence factors during MDSPE,including saponification conditions,extraction and desorption time,amount of magnetic adsorbent and desorption conditions were investigated.Under the optimum conditions,the inter-day precision and intra-day precision for ergosterol were 2.1%and 3.2%,respectively.The results showed a good linear relationship in the range of 0.027-1.08mg/m L,and the recovery was 98.02%.Distinctively,the content of ergosterol under different drying methods differs from each other,and freeze-dried could better preserve the ergosterol with the content of 7.92 mg/g,while the microwave damaged most of the ergosterol with the content of 1.05mg/g.