Wong King Yee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 117-131). / Abstracts in English and Chinese. / Committee Memebers --- p.i / Acknowledgement --- p.ii / Abstract --- p.iii / 摘要 --- p.vi / List of Tables --- p.viii / List of Figures --- p.xiii / Abbreviations --- p.xv / Content --- p.xvii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Colonic fermentation --- p.1 / Chapter 1.1.1 --- The large intestine and the intestinal microflora --- p.1 / Chapter 1.1.2 --- Major substrates and products of colonic fermentation --- p.2 / Chapter 1.1.3 --- Beneficial bacteria --- p.6 / Chapter 1.2 --- Prebiotics --- p.7 / Chapter 1.2.1 --- Definitions of probiotics and prebiotics --- p.7 / Chapter 1.2.2 --- General characteristics of prebiotics --- p.8 / Chapter 1.2.3 --- Current studies on prebiotics --- p.9 / Chapter 1.2.3.1 --- Non-β3-glucan typed prebiotics --- p.9 / Chapter 1.2.3.2 --- β-glucan type prebiotics --- p.11 / Chapter 1.3 --- Potential β-glucan type prebiotics --- p.12 / Chapter 1.3.1 --- Commercial sources of β (l→3) glucans as potential prebiotics --- p.12 / Chapter 1.3.1.1 --- Pachyman (PAC) and carboxymethylated-pachyman (CM-PAC)… --- p.13 / Chapter 1.3.1.2 --- Curdlan (CUR) and carboxymethylated curdlan (CM-CUR) --- p.13 / Chapter 1.3.1.3 --- Laminarian (LAM) --- p.14 / Chapter 1.3.2 --- Non-digestible carbohydrates (NDC) from mushroom --- p.14 / Chapter 1.3.2.1 --- Mushroom sclerotia as a good source of β-glucan --- p.14 / Chapter 1.3.2.2 --- Poria cocos (PC) sclerotia --- p.15 / Chapter 1.3.2.3 --- Oligosaccharide preparation from PC sclerotium --- p.16 / Chapter 1.4 --- Microbial analysis by molecular methods --- p.19 / Chapter 1.4.1 --- Traditional cultural techniques --- p.19 / Chapter 1.4.2 --- Newly emerging molecular techniques --- p.23 / Chapter 1.5 --- Objectives and significance of the present study --- p.27 / Chapter Chapter 2 --- Materials and Methods --- p.28 / Chapter 2.1 --- Materials --- p.28 / Chapter 2.1.1 --- Commercial β-glucans --- p.28 / Chapter 2.1.2 --- β-glucan from Poria cocos sclerotium --- p.28 / Chapter 2.2 --- Chemical characterization of Poria cocos sclerotium --- p.30 / Chapter 2.2.1 --- Lowry method for soluble protein determination --- p.30 / Chapter 2.2.1.1 --- Reagents --- p.30 / Chapter 2.2.1.2 --- Determination of soluble protein content --- p.30 / Chapter 2.2.2 --- Total sugar content analysis (Phenol-sulphuric acid method) --- p.31 / Chapter 2.2.3 --- Total dietary fiber analysis --- p.31 / Chapter 2.2.3.1 --- Digestible carbohydrate and protein removal by enzyme treatment --- p.32 / Chapter 2.2.3.2 --- Total dietary fiber content determination --- p.32 / Chapter 2.3 --- Structural characterization of PSS and other commercial β-glucans --- p.35 / Chapter 2.3.1 --- Monosaccharide profile study by gas chromatography (GC) --- p.35 / Chapter 2.3.1.1 --- Acid depolymerisation --- p.35 / Chapter 2.3.1.2 --- Neutral and amino sugar derivatization --- p.35 / Chapter 2.3.1.3 --- Determination of neutral sugars by gas chromatography (GC) --- p.36 / Chapter 2.3.2 --- Structural study of polysaccharides by methylation --- p.37 / Chapter 2.3.2.1 --- Preparation of dry dimethyl sulfoxide (DMSO) --- p.37 / Chapter 2.3.2.2 --- Preparation of methylsulfinyl methyl sodium (CH3SOCH2-Na+) from the dry DMSO and sodium hydride --- p.37 / Chapter 2.3.2.3 --- Methylation procedure --- p.38 / Chapter 2.3.2.4 --- Preparation of partially methylated alditol acetates (PMAAs) --- p.39 / Chapter 2.3.2.5 --- Analysis of the PMAAs by GC-MS --- p.39 / Chapter 2.3.3 --- Intrinsic viscosity determination --- p.40 / Chapter 2.4 --- Enzymatic digestion of PSS --- p.43 / Chapter 2.4.1 --- Optimization of digestion Conditions --- p.43 / Chapter 2.4.2 --- Large scale oligosaccharide preparation by preparative HPLC --- p.43 / Chapter 2.5 --- In vitro fermentation of β-glucans --- p.45 / Chapter 2.5.1 --- Static Batch culture in vitro fermentation using human fecal inoculum --- p.45 / Chapter 2.5.2 --- Determination of organic matter disappearance (OMD) --- p.47 / Chapter 2.6 --- Gas chromatographic determination of SCFAs --- p.49 / Chapter 2.7 --- Microbial identification and enumeration --- p.52 / Chapter 2.7.1 --- Oligonucleotide probes for fluorescent in situ hybridization --- p.52 / Chapter 2.7.2 --- Fluorescent in situ hybridization (FISH) --- p.52 / Chapter 2.7.2.1 --- Cell Fixation --- p.53 / Chapter 2.7.2.2 --- In situ hybridization --- p.53 / Chapter 2.8 --- Statistical analysis --- p.54 / Chapter Chapter 3 --- Results and discussions --- p.55 / Chapter 3.1 --- Chemical characterization of Poria cocos sclerotium --- p.55 / Chapter 3.2 --- Structural characterization of PSS & other commercial β-glucans --- p.56 / Chapter 3.2.1 --- Monosaccharide profile --- p.56 / Chapter 3.2.2 --- Glycosidic linkages in polysaccharides --- p.58 / Chapter 3.2.3 --- Molecular weight comparison as determined by intrinsic viscosity --- p.59 / Chapter 3.3 --- Preparation of β (1→3) glucose-based oligosaccharides --- p.66 / Chapter 3.3.1 --- Enzymatic digestion of PSS --- p.66 / Chapter 3.3.2 --- Preparation of (3 (1 →3) glucose-based oligosaccharides by preparative HPLC --- p.66 / Chapter 3.4 --- Batch culture in vitro fermentation --- p.70 / Chapter 3.4.1 --- Organic matter disappearance (OMD) --- p.70 / Chapter 3.4.2 --- Time course study of SCFA production --- p.74 / Chapter 3.4.2.1 --- Total SCFA production --- p.74 / Chapter 3.4.2.2 --- "Individual SCFA (Acetate, Propionate and Butyrate)" --- p.76 / Chapter 3.4.3 --- Overall production of total and individual SCFA --- p.84 / Chapter 3.4.4 --- Molar ratio of SCFAs --- p.90 / Chapter 3.4.5 --- Summary --- p.94 / Chapter 3.5 --- Microbial identification and enumeration by FISH --- p.95 / Chapter 3.5.1 --- Time course relationship --- p.95 / Chapter 3.5.1.1 --- Total bacterial count --- p.95 / Chapter 3.5.1.2 --- Bifidobacteria --- p.97 / Chapter 3.5.2 --- Comparison of bifidogenic properties in the β-glucans --- p.105 / Chapter 3.5.3 --- Summary --- p.108 / Chapter 3.6 --- Correlation between various parameters during in vitro fermentation of β_ glucans --- p.110 / Chapter Chapter 4 --- Conclusions --- p.113 / Chapter 4.1 --- Prebiotic potential of β (1→3) glucans --- p.113 / Chapter 4.2 --- Future Work --- p.115 / List of References: --- p.117