Analysis Of Nutritional Components And Cadmium Binding Protein Of Boletus Edulis Produced In Yunnan Province

In this study,the wild edible Boletus griseus from Yunnan were selected as research material,and the proximate composition,hydrolytic amino acid composition,free amino acid composition and mineral elements of B.griseus in different regions were determined.What's more,speciation analysis and edible safety of Cd in B.griseus were compared.The Cd-binding protein from B.griseus was purified and analyzed.The main results were as follows:1.The crude protein,crude fat,crude ash,soluble total sugar,polyphenol,crude fiber and total acid contents of B.griseus from different regions in Yunnan were 20.80?34.74%,1.21?3.64%,6.66?8.78%,8.41-15.69%,5.61?11.00 mg/g,1.97?8.00%and 7.62?18.15 g/kg,respectively.The results showed that B.griseus had the characteristics of high protein,low fat,rich in polysaccharides and polyphenols.The total content of hydrolytic amino acids was 155.95?320.36 mg/g DW,and the glutamic acid and aspartic acid in the eighteen kinds of hydrolytic amino acids were the highest.The protein nutritional value of B.griseus in different regions was relatively high,and there were some differences between different regions.The total content of free amino acids was 23.41?51.10 mg/g DW,and twenty seven-thirty one kinds of free amino acids were detected,containing 40?50%of the flavor amino acids.The principal component analysis showed that thirty one kinds of free amino acids could be divided into eight main components,and the cumulative contribution rate was 91.944%.Clustering analysis showed that the twenty six regions were divided into four groups.2.The twelve kinds of mineral elements content of B.griseus from different regions in Yunnan were Cd(5.23-25.01 mg/kg),Pb(0.17?1.24 mg/kg),Cr(14.76?79.23 mg/kg),Mn(16.30?50.25 mg/kg),Ni(0.40?2.85 mg/kg),Mg(619.88?1160.10 mg/kg),Cu(11.63?49.88 mg/kg),Fe(50.36?532.69 mg/kg),Zn(64.37?183.24 mg/kg),Na(187.77?601.77 mg/kg),Ca(1527.12?4308.00 mg/kg)and K(36060?53460 mg/kg),respectively.The principal component analysis showed that twelve kinds of mineral elements could be divided into five main components,and the cumulative contribution rate was 78.491%.3.The BCF values of Cd in B.griseus from different regions in Yunnan were all more than one,indicating that B.griseus had strong enrichment ability to Cd.So we should avoid excessive consumption or long term consumption.The distribution of Cd in B.griseus was lamella>cap>stipe.The protein contents of albumin and globulin were 18.82%and 4.59%,respectively,and the contents of Cd were 7.20 mg/kg and 5.59 mg/kg.It indicated that Cd in B.griseus had a certain exposure risk to the human body.4.The Cd of four fractions obtained by Sephadex G-75 purification was different,and the Cd in fraction A was the highest,which was 46.44%.Therefore,fraction A was the target Cd-binding protein.SDS-PAGE analysis showed that fraction A was not a single protein,whereas FT-IR spectra showed that the secondary structure of fraction A was predominantly a-helix.The most clear protein band Ai in fraction A were analyzed by mass spectrometry.The results showed that the protein A1 matched with P42740,and the peptide coverage was 39%.