| Boletus is a medicinal and edible fungus with high nutritional value and biological activity.The geographical environment and climatic conditions of Aksu provide convenience for the growth of boletus,but over-excavation makes wild boletus resources seriously affected damage.At present,there are few reports on wild boletus in this area.The research on wild boletus in this paper mainly focuses on identification,nutritional evaluation,extraction and function of polysaccharides,etc,to provide a basis for the rational utilization of wild boletus resources.The main results are as follows:(1)The wild bolete was identified as Leccinum duriusculum by morphological and molecular biological means,belonging to the order Agaric,Boletaceae,Boletus verrucous;12 were isolated.The endophytic fungi involved 10 genera and 12 species.There were 7 strains with more than 99%homology and 5 strains with less than 99%homology.Among them,2 strains were suspected to be new species.(2)The nutritional composition of the bovine liver wart is determined by the sugar content of the bovine liver wart,the total sugar content(57.57%)was 5 times higher than that of Boletus flavus(10.11%)and Boletus flavus(10.35%),and 20 times higher than that of Boletus fulvus(2.64%);The content of Ca(670mg/kg)in mineral elements is 60 times higher than that of Red Bull liver bacteria(11mg/kg),which is characterized by high calcium;a total of 40 volatile components were identified,including alcohols(49.86%)、aldehydes(24.69%)、ketones(12.39%)、hydrocarbons(11.16%)、benzene(1.15%)and esters(0.71%),among which 1-octene-3-alcohol、3-octanone and isovaleraldehyde were the main characteristic flavor substances of Boletus verrucosa.(3)The crude polysaccharide of Boletus versicolor was extracted by water extraction and alcohol precipitation.The extraction conditions of polysaccharide were optimized by single factor and orthogonal design.The optimal extraction parameters were determined as follows:the ratio of extraction material to liquid was 1:30,the temperature was 80℃and the time was 3h.Under this combination,the yield of polysaccharide was 13.36%。(4)The polysaccharide components LD-40 and LD-80 were obtained by ethanol fractional precipitation.The two polysaccharide components showed different characteristics.Among them,the viscosity and water holding capacity of LD-40 were stronger than those of LD-80,and their water solubility were 66.9%respectively and 74.9%,and the water holding capacity of 7.71g/g and 6.16g/g;the two polysaccharide components have weak antioxidant capacity,when the polysaccharide concentration reaches 10 mg/m L,the ability of LD-80 to scavenge DPPH and OH~-radical reaches 48%and 52%,and the ability of the LD-40 to scavenge DPPH and OH~-radical only reaches 15%and 29%.(5)Three fractions(LD-1、LD-2 and LD-3)were obtained by eluting with distilled water、0.1 M Na Cl and 0.2 M Na Cl using DEAE-52 cellulose column chromatography.Among them,LD-1(61%)has a stronger water solubility and LD-2(24.06g/g)has a stronger water holding capacity.UV spectrum shows that the three polysaccharides do not contain nucleic acid and protein,and the infrared spectrum shows that the three polysaccharides contain carbohydrate compounds,and glucose accounts for the highest proportion.The monosaccharide composition showed that the monosaccharides in LD-1 were glucose,rhamnose,fructose and arabinose,among which glucose had the highest molar percentage. |
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