Lo Kit Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 193-208). / Abstracts in English and Chinese. / THESIS COMMITTEE --- p.i / ACKNOWLEDGEMENTS --- p.ii / ABSTRACT --- p.iii / ABSTRACT (Chinese version) --- p.v / CONTENT --- p.vii / LIST OF TABLES --- p.xiii / LIST OF FIGURES --- p.xviii / LIST OF ABBREVIATIONS --- p.xx / Chapter CHAPTER 1: --- INTRODUCTION --- p.1 / Chapter 1.1 --- An introduction of natural antioxidants --- p.1 / Chapter 1.1.1 --- Definition of antioxidants --- p.1 / Chapter 1.1.2 --- Application of natural antioxidants in foods --- p.3 / Chapter 1.1.2.1 --- Oxidation of foods --- p.3 / Chapter 1.1.2.1.1 --- Autoxidation of food --- p.3 / Chapter 1.1.2.1.2 --- Photo-oxidation of food --- p.4 / Chapter 1.1.3 --- Free radicals and antioxidants --- p.6 / Chapter 1.1.3.1 --- Free radicals and reactive oxygen species --- p.6 / Chapter 1.1.3.1.1 --- Superoxide anion radical --- p.8 / Chapter 1.1.3.1.2 --- Hydrogen peroxide --- p.9 / Chapter 1.1.3.1.3 --- Hydroxyl radical --- p.10 / Chapter 1.1.3.1.4 --- Peroxyl radical --- p.12 / Chapter 1.1.3.1.5 --- Lipid peroxidation of cell membranes --- p.13 / Chapter 1.1.3.1.6 --- Oxidation of LDL and atherosclerosis --- p.16 / Chapter 1.1.4 --- Natural antioxidants and their mechanisms --- p.18 / Chapter 1.1.4.1 --- Carotenoids --- p.18 / Chapter 1.1.4.2 --- Phenolic compounds --- p.20 / Chapter 1.1.4.2.1 --- Flavonoids --- p.21 / Chapter 1.1.4.2.2 --- Phenolic acids --- p.22 / Chapter 1.1.4.3 --- Sterols --- p.24 / Chapter 1.1.4.4 --- Vitamins --- p.25 / Chapter 1.2 --- Antioxidant in mushrooms --- p.27 / Chapter 1.2.1 --- Antioxidant properties of mushrooms --- p.27 / Chapter 1.2.2 --- Characterization of mushroom phenolic antioxidants --- p.30 / Chapter 1.2.3 --- Biosynthesis of phenolic compounds in mushrooms or fungi --- p.33 / Chapter 1.3 --- Assays for evaluation of antioxidants --- p.35 / Chapter 1.3.1 --- Beta-carotene bleaching method --- p.35 / Chapter 1.3.2 --- Scavenging activity of DPPH radical --- p.36 / Chapter 1.3.3 --- Erythrocyte hemolysis --- p.36 / Chapter 1.3.4 --- Scavenging activity of ABTS ´Ø + radical cation --- p.37 / Chapter 1.3.5 --- Scavenging activity of hydroxyl radical --- p.37 / Chapter 1.3.6 --- Assay for lipid peroxidation of rat brain homogenate --- p.38 / Chapter 1.3.7 --- Inhibition of low-density lipoproteins (LDLs) oxidation --- p.39 / Chapter 1.4 --- Analysis of phenolic antioxidants --- p.41 / Chapter 1.4.1 --- Extraction of phenolic compounds --- p.41 / Chapter 1.4.2 --- Determination of total phenolic content --- p.43 / Chapter 1.4.3 --- Chromatographic fractionation of phenolic compounds --- p.44 / Chapter 1.4.4 --- Characterization of phenolic compounds --- p.45 / Chapter 1.4.4.1 --- Thin-layer chromatography (TLC) --- p.45 / Chapter 1.4.4.2 --- High performance liquid chromatography (HPLC) --- p.46 / Chapter 1.4.4.3 --- Liquid chromatography-Mass spectrometry (LC-MS) --- p.47 / Chapter 1.5 --- Objectives --- p.49 / Chapter CHAPTER 2: --- MATERIALS AND METHODS --- p.50 / Chapter 2.1 --- Sample preparation --- p.50 / Chapter 2.2 --- Sample extraction. --- p.51 / Chapter 2.2.1 --- Small-scale methanol and water extraction --- p.51 / Chapter 2.2.2 --- Large-scale methanol and water extraction and fractionation --- p.54 / Chapter 2.2.2.1 --- Large-scale methanol and water extraction --- p.54 / Chapter 2.2.2.2 --- Fractionation of crude extracts --- p.55 / Chapter 2.2.2.2.1 --- Fractionation of methanol crude extract --- p.55 / Chapter 2.2.2.2.2 --- Fractionation of water crude extract --- p.55 / Chapter 2.3 --- Fractionation by column chromatography --- p.58 / Chapter 2.4 --- Assays for measuring antioxidant activity --- p.60 / Chapter 2.4.1 --- Beta-carotene bleaching method --- p.60 / Chapter 2.4.2 --- Scavenging activity of DPPH radical --- p.62 / Chapter 2.4.3 --- Erythrocyte hemolysis --- p.63 / Chapter 2.4.4 --- Scavenging activity of ABTS ´Ø + radical cation --- p.64 / Chapter 2.4.5 --- Scavenging activity of hydroxyl radical --- p.65 / Chapter 2.4.6 --- Assay for lipid peroxidation of rat brain homogenate --- p.66 / Chapter 2.4.7 --- Inhibition of human low-density lipoproteins (LDLs) oxidation --- p.67 / Chapter 2.4.7.1 --- Isolation of human LDLs --- p.67 / Chapter 2.4.7.2 --- Calculation of density --- p.68 / Chapter 2.4.7.3 --- Lowry's method for determination of protein content --- p.69 / Chapter 2.4.7.4 --- Preparation of reagents --- p.69 / Chapter 2.4.7.5 --- Determination of thiobarbituric acid reactive substance (TBARS) --- p.70 / Chapter 2.5 --- Total phenolic content --- p.70 / Chapter 2.6 --- Total carbohydrate content --- p.71 / Chapter 2.7 --- Determination of protein content- the Biuret method --- p.71 / Chapter 2.8 --- Thin-layer chromatography (TLC) --- p.72 / Chapter 2.9 --- High performance liquid chromatography (HPLC) --- p.73 / Chapter 2.9.1 --- Analysis of subfractions of methanol crude extract --- p.73 / Chapter 2.9.2 --- Analysis of fractionated subfractions and subfractions of Pevf and Aa mushrooms --- p.74 / Chapter 2.10 --- Liquid chromatography- Mass spectrometry (LC-MS) --- p.74 / Chapter 2.10.1 --- Liquid chromatography --- p.74 / Chapter 2.10.2 --- Mass spectrometry --- p.75 / Chapter 2.11 --- Data analysis --- p.75 / Chapter CHAPTER 3: --- RESULTS AND DISCUSSION --- p.77 / Chapter 3.1 --- Small-scale extraction scheme --- p.77 / Chapter 3.1.1 --- Extraction yield --- p.77 / Chapter 3.1.2 --- Assays for measuring antioxidant activity --- p.80 / Chapter 3.1.2.1 --- Beta-carotene bleaching method --- p.80 / Chapter 3.1.2.2 --- Scavenging activity of DPPH radical --- p.91 / Chapter 3.1.2.3 --- Erythrocyte hemolysis --- p.98 / Chapter 3.1.2.4 --- Summary for small-scale extraction --- p.105 / Chapter 3.2 --- Large-scale extraction and fractionation scheme --- p.107 / Chapter 3.2.1 --- Extraction yield for crude extracts and subfractions --- p.107 / Chapter 3.2.2 --- Antioxidant activity of subfractions and crude extracts of Aa and Pevf mushrooms --- p.111 / Chapter 3.2.2.1 --- Scavenging activity of ABTS ´Ø + radical cation --- p.111 / Chapter 3.2.2.2 --- Scavenging activity of hydroxyl radical --- p.114 / Chapter 3.2.2.3 --- Assay for lipid peroxidation of rat brain homogenate --- p.125 / Chapter 3.2.2.4 --- Summary for large-scale extraction --- p.135 / Chapter 3.2.3 --- Chemical characterization of the crude extracts and their sub fractions of Aa and Pevf mushrooms --- p.13 8 / Chapter 3.2.3.1 --- Total phenolic content --- p.139 / Chapter 3.2.3.1.1 --- Total phenolic content of crude extract and their sub fractions of Aa and Pevf mushrooms --- p.139 / Chapter 3.2.3.1.2 --- Correlation between total phenolic content and antioxidant activity --- p.140 / Chapter 3.2.3.2 --- Total carbohydrate content --- p.144 / Chapter 3.2.3.2.1 --- Total carbohydrate content of water crude extract and their sub fractions of Aa and Pevf mushrooms --- p.144 / Chapter 3.2.3.2.2 --- Correlation between total carbohydrate content and antioxidant activity --- p.144 / Chapter 3.2.3.3 --- Determination of protein content- the Biuret method --- p.146 / Chapter 3.2.3.3.1 --- Protein content of water crude extract and their sub fractions of Aa and Pevf mushrooms --- p.146 / Chapter 3.2.3.3.2 --- Correlation between protein content and antioxidant activity --- p.147 / Chapter 3.2.3.4 --- Summary of correlation between chemical components and antioxidant activity --- p.148 / Chapter 3.3 --- Column fractionation of ethyl acetate and butanol subfractions of Aa mushroom --- p.151 / Chapter 3.3.1 --- Rf value in TLC and yield of fractionated subfractions --- p.151 / Chapter 3.3.2 --- Total phenolic content of fractionated subfractions --- p.153 / Chapter 3.3.3 --- Antioxidant activity of fractionated subfractions --- p.155 / Chapter 3.3.3.1 --- Scavenging activity of ABTS ´Ø + radical cation --- p.155 / Chapter 3.3.3.2 --- Scavenging activity of DPPH radical --- p.158 / Chapter 3.3.3.3 --- Inhibition of human low-density lipoprotein (LDL) oxidation --- p.163 / Chapter 3.4 --- Chromatographic characterization of the subfractions of methanol crude extract of Aa and Pevf mushrooms --- p.167 / Chapter 3.4.1 --- Thin-layer chromatography (TLC) --- p.167 / Chapter 3.4.2 --- High performance liquid chromatography (HPLC) --- p.172 / Chapter 3.5 --- Chromatographic and spectrometric characterization of the fractionated subfractions of the ethyl acetate and butanol subfractions of Aa --- p.177 / Chapter 3.5.1 --- High performance liquid chromatography (HPLC) --- p.177 / Chapter 3.5.2 --- Liquid chromatography- Mass spectrometry (LC-MS) --- p.186 / Chapter CHAPTER 4: --- CONCLUSION --- p.189 / REFERENCES --- p.193 / RELATED PUBLICATION --- p.209
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_324355 |
| Date | January 2003 |
| Contributors | Lo, Kit Man., Chinese University of Hong Kong Graduate School. Division of Food and Nutritional Sciences. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, bibliography |
| Format | print, xxiii, 209 leaves : ill. (some col.) ; 30 cm. |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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