發(fā)布時(shí)間：2024-12-21 01:11

　　食用菌多糖具有諸多藥理作用,是食用菌中重要的生物活性成分。眾所周知的,提取方法會(huì)極大的影響食用菌多糖的化學(xué)結(jié)構(gòu),進(jìn)而影響其生物活性,采用新型快速、有效的多糖提取技術(shù)對(duì)食用菌多糖具有重要意義。在本文中,我們研究了兩種新提取技術(shù)對(duì)金福菇（Tricholoma lobayense）和羊肚菌（Morchella esculenta）多糖的提取效果,闡明了提取方法對(duì)其提取率、結(jié)構(gòu)及生物活性的影響。主要研究?jī)?nèi)容如下:1.閃提對(duì)金福菇多糖結(jié)構(gòu)及抗氧化性的影響以水為溶劑對(duì)金福菇多糖進(jìn)行閃式提取,對(duì)獲得的多糖TLH-G進(jìn)行結(jié)構(gòu)解析和抗氧化性研究。研究發(fā)現(xiàn)TLH-G是一種分子量為4.1×10～3 Da的雜多糖,總糖、蛋白質(zhì)和糖醛酸的含量分別為99.10%、0.72%和13.85%。單糖組成為甘露糖、鼠李糖、葡萄糖醛酸、葡萄糖和半乳糖,摩爾比為1.00:0.33:0.56:14.13:2.92,其主鏈由→1)-β-D-Glcp-（6→和→1）-α-D-Galp-(3→構(gòu)成�？寡趸�性研究表明TLH-G的DPPH和ABTS自由基的清除的IC₅₀值分別為0.43 mg/mL和>0.5 m...

【文章頁(yè)數(shù)】：102 頁(yè)

【學(xué)位級(jí)別】：博士

【文章目錄】：
Acknowledgements
摘要
abstract
Chapter1.Introduction to polysaccharides from edible fungi and their extraction techniques
    1.1.Medicinal mushrooms
    1.2.Nutritious significance of mushrooms
    1.3.Mushroom bioactives
        1.3.1.Mushroom polysaccharides
            1.3.1.1.Glucans
            1.3.1.2.Chitin and chitosan
            1.3.1.3.Mannans and mannoproteins
        1.3.2.Other nutritious portions of mushrooms
    1.4.Structural properties of mushroom polysaccharides
    1.5.Conventional extraction methods for mushrooms
        1.5.1.Solvent-assisted extraction(SAE)
            1.5.1.1.Hydro-alcohol extractions
    1.6.Emerging technologies for polysaccharide extraction
        1.6.1.Ultrasound-assisted extraction(UAE)
        1.6.2.Enzyme-assisted extraction(EAE)
        1.6.3.Microwave-assisted extraction(MAE)
        1.6.4.Accelerated-solvent Extraction(ASE)or pressurized liquid extraction(PLE)
        1.6.5.Supercritical fluid extraction(SFE)
        1.6.6.Pulsed-electric field extraction(PEF)
        1.6.7.High-pressure homogenization extraction(HPH)
        1.6.8.Flash-assisted extraction(FAE)
        1.6.9.Hydrothermal extraction or subcritical water/pressurized hot water extraction
            1.6.9.1.Mechanisms involved during hydrothermal extraction
            1.6.9.2.Parameters affecting hydrothermal extraction
    Aims and objectives
    References
Chapter2.Structural elucidation and antioxidant activity of a novel heteroglycan from Tricholoma lobayense by flash extraction
    2.1.Introduction
    2.2.Experimental Section
        2.2.1.Materials and apparatus
        2.2.2.Extraction procedure
        2.2.3.Deproteination and purification
        2.2.4.Physical and chemical properties analysis
        2.2.5.Analysis of monosaccharide composition
        2.2.6.Methylation and GC-MS analysis
        2.2.7.NMR spectroscopy
        2.2.8.Antioxidant activity assays
            2.2.8.1.DPPH radical scavenging assay
            2.2.8.2.ABTS assay
    2.3.Results and discussions
        2.3.1.Physical and chemical properties of TLH-G
        2.3.2.FT-IR analysis of TLH-G
        2.3.3.TLH-G monosaccharide analysis and their effect on antioxidant activity
        2.3.4.Structural characterization of TLH-G via GC-MS analysis
        2.3.5 NMR analysis of TLH-G
        2.3.6.Antioxidant activity evaluation by DPPH and ABTS assays
        2.3.7.Glycosidic bond types in TLH-G polysaccharides
    References
Chapter3.Extraction of polysaccharides from Tricholoma lobayense by hydrothermal methodology
    3.1.Introduction
    3.2.Experimental section
        3.2.1.Materials and methods
        3.2.2.Extraction of Tricholoma lobayense mushroom
        3.2.3.Total carbohydrate and protein content
        3.2.4.Extraction at ideal conditions
        3.2.5.Purification of T.lobayense polysaccharides
        3.2.6.Antioxidant activity assays
            3.2.6.1.DPPH radical scavenging activity assay
            3.2.6.2.ABTS radical scavenging activity assay
            3.2.6.3.Hydroxyl radical scavenging activity assay
            3.2.6.4.Reducing power
            3.2.6.5.Superoxide radical scavenging activity assay
    3.3.Results and discussions
        3.3.1.Extraction parameters and optimization
        3.3.2.Optimization of ratio of solid to liquid(g/mL)
        3.3.3.Optimization of temperature
        3.3.4.Optimization of extraction time
        3.3.5.In vitro antioxidant assays
    References
Chapter4.Effects of hydrothermal extraction on polysaccharides from Morchella esculenta
    4.1 Introduction
    4.2.Experimental Section
        4.2.1.Materials and reagents
        4.2.2.Extraction of mushroom
        4.2.3.Purification of Morchella esculenta polysaccharides
        4.2.4.Total carbohydrate and protein content analysis
        4.2.5.In vitro Antioxidant activity assays
            4.2.5.1.DPPH radical scavenging assay
            4.2.5.2.ABTS radical scavenging assay
            4.2.5.3.Reducing power
            4.2.5.4.Hydroxyl radical scavenging assay
        4.2.6.Ethanol gradient precipitation
        4.2.7.HPLC analysis
        4.2.8.CTAB treatment
    4.3.Results and discussions
        4.3.1.Total sugar,protein,and in vitro antioxidant activities of M.esculenta polysaccharides
        4.3.2.Fractionation by ethanol gradient precipitation and their HPLC analysis
    References
Chapter5.Conclusions
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