| Flammunlinavelutipes is a kind of edible fungus reputed for its high nutrition and medicinal value.It contains avariety of functional active compounds.The base of Flammulina velutipes stipe was mostly underutilized and abandoned in the process of harvesting and production.Leading to environmental pollution and waste of resources.Based on the base of Flammulina velutipes stipe as a raw material,investigated optimization of extraction of proteins,studied the functional properties of proteins and analysis of properties of enzyme reaction of the proteins.The main contents and results in details were as follows:(1)The nutrition component analysis of Flammunlina velutipes showed that:the proteins content of upper and root respectively were 22.75?19.53 g·(100g)-1,the contents of polysaccharide respectively was 37.54?47.02g·(100g)-1,contents of Vitamin C respectively was 53.26mg·(100g)-1?34.97mg·(100g)-1,Contents of polyphenol respectively was7.38mg·g-1?6.88mg·g-1.Two parts both contain 48 kinds of minerals,contains not only common elements necessary to human body such as K,Na,Ca,Mg,etc.but also all kinds of minerals and trace elements which were good for human health such as Zn?Fe?Mn?Se.Except Fe,Root contented higher than the upper portion.Kinds of amino acids were complete in both parts.Contents of total amino acid respectively were 35.10%?32.87%.Consequently,Flammunlina velutipes was a high protein,low fat,active polysaccharide edible fungus which contained many kinds of mineral sub-stances and amino acid.(2)Optimization of extraction of proteins from the root of Flammulina velutipes.The effects of extraction reagent,degree of grinding,ratio of solid to liquid,extracting temperature,time,leaching solution pH value and times of extracting on the extraction of the proteins of root of Flammulina velutipes were investigated.Response surface methodology was used to optimize the extraction processing of protein and establish the mathematical model of proteins extraction rate.Factor contribution rate obtained from the F-test were as follows:solid-liquid ratio>extraction pH>extraction time>extraction temperature.The optimum extraction parameters were obtained as follows:ratio of solid to liquid 1:16g·mL-1,extraction temperature30?,extraction time 30min,and extraction pH10.The predicated extraction rate of proteins was 64.75%meanwhile the rate of proteins was 64.91%in the validated experiment with the relative deviation value of 0.25%.On the basis of Alkaline extraction experiments,ultrasonic factors were investigated.The optimum extraction parameters obtained from response surface analysis were as follows:ultrasonic power 124.33W,extraction temperature 29.40?,ultrasonic time 19.76 min.By using the optimized extraction parameters,the extraction rate of proteins was 73.22%.(3)The physicochemical properties of protein from root of Flammunlina velutipes analysis of showed that:It was pH4 that the isoelectric point(pI)of proteins of Flammunlina velutipes.The molecular weight of the extracted proteins mainly distributed in24?35 kDa,45?50 kDa and 70?120 kDa area,The maximum area was in 32 kDa.These proteins contained 8 kinds of EAA and highest content of glutamic acid,which were accorded with FAO/WHO Ideal Protein System.According to the nutritional evaluation of amino acid,the first limited amino acid was methionine and homocysteine in alkali extraction proteins,while it was leucine in ultrasound-assisted extraction proteins.According to IR spectrum,the mainly component unit in different protein extraction method were both a-helix and ?-sheet.Differential Scanning Calorimetry(DSC)analysis the distortion temperature of proteins respectively were 73.07?and 73.45?,while the degeneration heat respectively were 1.229 J·g-1 and 2.545J·g-1.In isoelectric point of proteins,the functional properties of proteins,such as solubility,emulsifying activity and foaming capability were lowest,but emulsification and foamability stability were best.In the suitable temperature range,The functional properties of proteins were improved as the temperature rose,while it was decreased with temperature higher than 50?.Ultrasound-assisted extraction protein was better in terms of solubility,emulsifiability and water-holding ability.Alkali extraction proteins were better in terms of hydrophobic,foaming capacity and holding oiliness ability.(4)Study on enzymatic hydrolysis and oxidation resistance of protein from root of Flammulina velutipes.Four proteases(Protamex?Neutrase?Alcalase?Papain)were used to hydrolyze the proteins from root of Flammulina velutipes at their suitable conditions.The degree of hydrolysis(DH),protein recovery(PR),and antioxidant activities of hydrolysates were compared.It turned out that the abilities of of hydrolysates on scavenging DPPH.,hydroxyl and reducibility were ignificantly increased.When synthesized the effects of enzymatic hydrolysis,we found that growth rate of Enzymolysis products was stable.In the meantime the oxidation resistance was maximum after 120min.The abilities of scavenging DPPH · and reducibility which enzymolysis products were enzymolysised by Protamex were 69.72%and 0.96.· OH scavenge ability of Alcalase2.4L's Enzymolysis products was 73.63%.Protamex was the most suitable protease for the Protein,compared comprehensively for its highest DH,PR and antioxidant activities. |
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