Thesis (Ph. D.)--University of Wisconsin--Madison, 1982. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 225-232).

A method for separation and characterization of individual anthocyanins was developed. High Performance Liquid Chromatography (HPLC) with a polymer based reversed-phase column was used to separate the pigments while on-line Photodiode Array Detection (PDA) was employed to record the UV and Visible spectrum of the individual peaks. Spectral information obtained from on-line PDA detection provided information about: 1) the nature of the aglycone, 2) the sugar substitution pattern and 3) the presence or absence of hydroxy aromatic organic acids. The nature of the glycosidation can be determined from the HPLC retention characteristics. The HPLC/PDA methods were employed to characterize the anthocyanin profiles of the pigments in cranberry, roselle, cherry, bilberry, grape, red cabbage, black raspberry, blackberry, elderberry, plum, blackcurrant and strawberry. The anthocyanidin profiles were also determined for the samples for purposes of confirmation of the anthocyanin data. In addition to the anthocyanin and anthocyanidin profiles, the general coloring properties for most of the samples were also determined. Included were Hunter L, a, b values, total anthocyanin pigment concentration, wavelength maxima, percent tannin measurements, tinctoral strength, pH measurements and titratable acidity. / Graduation date: 1988

Jin, Lei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 150-170). / Abstracts in English and Chinese. / THESIS COMMITTEE --- p.II / ABSTRACT --- p.IV / 摘要 --- p.VI / TABLE OF CONTENTS --- p.VIII / LIST OF TABLES --- p.XII / LIST OF FIGURES --- p.",XIV" / LIST OF ABBREVIATIONS --- p.XVII / Chapter CHAPTER 1 --- GENERAL INTRODUCTION --- p.1 / Chapter 1.1 --- Background of Mushroom --- p.1 / Chapter 1.1.1 --- Mushroom --- p.1 / Chapter 1.1.2 --- Shiitake Mushroom --- p.2 / Chapter 1.1.3 --- Production of Shiitake mushroom --- p.3 / Chapter 1.1.4 --- Taxonomy of Shiitake --- p.4 / Chapter 1.1.5 --- Nutrients of Shiitake --- p.5 / Chapter 1.1.6 --- Taste Substances of Shiitake --- p.10 / Chapter 7.1.7 --- Aroma Components of Shiitake --- p.11 / Chapter 1.1.8 --- Color of Shiitake --- p.12 / Chapter 1.2 --- Food Additives --- p.13 / Chapter 1.2.1 --- Food Additives --- p.13 / Chapter 1.2.2 --- Definition of Food Additives Given by FA O/WHO Joint Expert Committee for Food Additives (JECFA) --- p.13 / Chapter 1.2.3 --- Definition of Food Additives Given by the Commission of the European Union --- p.14 / Chapter 1.3 --- Food Colorants and Stability Assessment --- p.15 / Chapter 1.3.1 --- "Define a Color: Color Space, Hue, and Chroma" --- p.15 / Chapter 1.3.2 --- Natural Pigment --- p.17 / Chapter 1.3.3 --- Food Color and use of Colorant --- p.17 / Chapter 1.3.4 --- Microbial Colors as Food Colorant --- p.19 / Chapter 1.3.5 --- Stability of Food Colorant --- p.23 / Chapter 1.4 --- Food Safety and Risk Assessment --- p.23 / Chapter 1.4.1 --- Food Safety --- p.23 / Chapter 1.4.2 --- The Codex Alimentarius --- p.24 / Chapter 1.4.3 --- National and Regional Authorities --- p.24 / Chapter 1.4.4 --- The Acceptable Daily Intake (ADI) and Other Related Safety Levels --- p.25 / Chapter 1.4.5 --- Toxicity Tests for Safety Assessment --- p.26 / Chapter 1.4.6 --- Sensitive Organs to Toxin (Liver and Kidney) --- p.29 / Chapter 1.5 --- Safety Assessment of Food Color Additives --- p.31 / Chapter 1.5.1 --- Color Additives (Food) --- p.31 / Chapter 1.5.2 --- Regulation of Color Additives --- p.33 / Chapter 1.6 --- Characterization of Natural Food Colorants --- p.33 / Chapter 1.6.1 --- Composition of Natural Food Colorants --- p.33 / Chapter 1.6.2 --- Fungal Pigments as Unique Alternatives of Authorized Natural Food Colorants --- p.34 / Chapter 1.6.3 --- Fungal Pigmentation and Phenolic Metabolism --- p.35 / Chapter CHAPTER 2 --- STABILITY ASSESSMENT OF THE EXUDATES FROM L. EDODES MYCELIA --- p.40 / Chapter 2.1 --- Introduction --- p.40 / Chapter 2.1.1 --- General Information --- p.40 / Chapter 2.1.2 --- Natural Sources of Food Colorant --- p.40 / Chapter 2.1.3 --- Application of Natural Pigments --- p.41 / Chapter 2.1.3 --- Objectives --- p.41 / Chapter 2.2 --- Material and Methods --- p.42 / Chapter 2.2.1 --- Cultivation of Shiitake Mushroom --- p.42 / Chapter 2.2.2 --- Collection of the Exudates --- p.42 / Chapter 2.2.3 --- Commercial Colorant --- p.42 / Chapter 2.2.4 --- Buffer Systems --- p.43 / Chapter 2.2.5 --- Soft Drink Medium --- p.43 / Chapter 2.2.6 --- Pigment Solution Sample Preparation --- p.44 / Chapter 2.2.7 --- Measurements of Physicochemical Parameters --- p.44 / Chapter 2.2.8 --- pH Stability --- p.45 / Chapter 2.2.9 --- Thermal Stability --- p.46 / Chapter 2.2.10 --- Light Stability --- p.46 / Chapter 2.2.11 --- Statistical Methods --- p.47 / Chapter 2.3 --- Results --- p.50 / Chapter 2.3.1 --- Physicochemical Characteristics --- p.50 / Chapter 2.3.2 --- pH Stability --- p.51 / Chapter 2.3.2 --- Thermal Stability --- p.53 / Chapter 2.3.3 --- Light Stability --- p.54 / Chapter 2.4 --- Discussion --- p.67 / Chapter 2.4.1 --- Physicochemical Characteristics --- p.67 / Chapter 2.4.2 --- pH Stability --- p.69 / Chapter 2.4.3 --- Thermal Stability --- p.71 / Chapter 2.4.4 --- Light Stability --- p.73 / Chapter CHAPTER 3 --- TOXICOLOGICAL STUDIES ON THE EXUDATES FROM L. EDODES MYCELIA --- p.76 / Chapter 3.1 --- Introduction --- p.76 / Chapter 3.1.1 --- L. edodes Mycelial Exudates ´ؤ a Promising Natural Food Colorant --- p.76 / Chapter 3.1.2 --- Regulatory Toxicology (Hazard Assessment) --- p.76 / Chapter 3.1.3 --- Acute and Sub-acute Toxicity Tests --- p.77 / Chapter 3.1.4 --- Color Additive Petitions --- p.78 / Chapter 3.1.5 --- Objectives --- p.80 / Chapter 3.2 --- Material and Methods --- p.80 / Chapter 3.2.1 --- Cultivation of Shiitake Mushroom and Test Substances --- p.80 / Chapter 3.2.1 --- Acute Toxicity Test --- p.81 / Chapter 3.2.1.1 --- Animals --- p.81 / Chapter 3.2.1.2 --- Limit Test --- p.81 / Chapter 3.2.1.3 --- Main Test --- p.82 / Chapter 3.2.2 --- Sub-acute Toxicity Test --- p.82 / Chapter 3.2.2.1 --- Animals and Administration of Test Substance --- p.82 / Chapter 3.2.2.2 --- Survival and Clinical Observations --- p.83 / Chapter 3.2.2.3 --- Body Weights and Food Consumption --- p.83 / Chapter 3.2.2.4 --- Hematology --- p.84 / Chapter 3.2.2.5 --- Clinical Chemistry --- p.84 / Chapter 3.2.2.6 --- Macroscopic Examination --- p.85 / Chapter 3.2.2.7 --- Histopathology --- p.85 / Chapter 3.2.3 --- Statistical Methods --- p.86 / Chapter 3.3 --- Results --- p.87 / Chapter 3.3.1 --- Oral Acute Toxicology Study in BALB/c Mice --- p.87 / Chapter 3.3.2 --- Oral Sub-acute Toxicology Study in SD Rat --- p.90 / Chapter 3.3.2.1 --- Survival and Clinical Observations --- p.90 / Chapter 3.3.2.2 --- Body Weights and Food Consumption --- p.90 / Chapter 3.3.2.3 --- Hematological and Clinical Biochemical Data --- p.92 / Chapter 3.3.2.4 --- Organ Weights --- p.92 / Chapter 3.3.2.5 --- Histopathological Examination --- p.92 / Chapter 3.4 --- Discussion --- p.103 / Chapter 3.4.1 --- General Aspects --- p.103 / Chapter 3.4.2 --- Oral Acute Toxicology Study in BALB/c Mice --- p.104 / Chapter 3.4.3 --- Oral Sub-acute Toxicology Study in SD Rat --- p.105 / Chapter CHAPTER 4 --- GENERAL CHARACTERIZATION AND APPLICATION OF EXUDATES FROM L. EDODES MYCELIA --- p.109 / Chapter 4.1 --- Introduction --- p.109 / Chapter 4.1.1 --- Pigmentation of Lentinula edodes --- p.109 / Chapter 4.1.2 --- Achieving Greater Bioavailability by Enzymatic Hydrolysis of Phenolics in Conjugated Forms --- p.110 / Chapter 4.1.3 --- Fourier Transform Ion Cyclotron Resonance Mass Spectrometry --- p.111 / Chapter 4.1.3 --- Objectives --- p.113 / Chapter 4.2 --- Material and Methods --- p.114 / Chapter 4.2.1 --- Cultivation of Fungus --- p.114 / Chapter 4.2.2 --- Sample Preparation of Fruiting Bodies and Mycelia --- p.114 / Chapter 4.2.3 --- Total Water-soluble Polysaccharide Content --- p.115 / Chapter 4.2.4 --- Total Protein Content --- p.115 / Chapter 4.2.5 --- Total Phenolic Content --- p.116 / Chapter 4.2.6 --- Enzymatic Hydrolysis of Glycosidically Bound Phenolic Compounds --- p.117 / Chapter 4.2.7 --- Measurement of Color Parameters --- p.117 / Chapter 4.2.8 --- Preparation of Exudates for FTICR-MS Analysis --- p.117 / Chapter 4.2.9 --- FTICR-MS Instrumentation --- p.118 / Chapter 4.2.10 --- FTICR-MS Calibration --- p.118 / Chapter 4.2.11 --- Quantitative Analysis of FTICR-MS --- p.119 / Chapter 4.2.12 --- Data Processing --- p.119 / Chapter 4.2.13 --- Sensory Evaluation --- p.120 / Chapter 4.3 --- RESULTS --- p.122 / Chapter 4.3.1 --- Major Chemical Groups of L. edodes --- p.122 / Chapter 4.3.2 --- Change in Color and Total Phenolic Content after Addition of Enzymes --- p.122 / Chapter 4.3.3 --- Detection of Metabolites Using FTICR-MS --- p.126 / Chapter 4.3.4 --- Phenolic Compound Identification --- p.129 / Chapter 4.3.5 --- Sensory Evaluation --- p.137 / Chapter 4.4 --- Discussion --- p.138 / Chapter 4.4.1 --- Total Phenolic Content and Pigmentation --- p.138 / Chapter 4.4.2 --- FTICR-MS Application on Studying Enzymatic Hydrolysis --- p.140 / Chapter 4.4.3 --- Sensory Evaluation --- p.147 / Chapter 4.4.4 --- Overall Conclusion --- p.147 / Chapter CHAPTER 5 --- CONCLUSION --- p.148 / REFERENCES --- p.150 / APPENDIX --- p.171

Thesis--Wisconsin. / Includes bibliographical references (leaves 38-41).

Thesis--Wisconsin. / Vita. Includes bibliographical references.

Submitted in complete fulfilment for the Degree of Master in Food Science and Technology, Durban University of Technology, 2017. / Hibiscus sabdariffa is an under-utilised plant that has been reported to have great potential in the pharmaceutical and nutraceutical industries. The vibrant red pigment indicates a source of anthocyanins that could be produced into a food colourant with additional nutritional benefits however stability is a hindering factor. The crude anthocyanins were extracted from dried calyces by means of four different acidified ethanol and methanol solvent systems to determine the maximum crude anthocyanin yield. The crude extracts were analysed under the following parameters; heat, light, pH stability and degradation kinetics, which included thermal degradation and DPPH radical scavenging ability. Two synthetic colourants were analysed based on the stability parameters; heat, light and pH and compared with the natural H. sabdariffa crude extracts. Each of the four crude extracts were analysed for the total phenolic content using Folin Ciocalteu’s method. The DPPH and FRAP assays were used to determine the radical scavenging activity of the extract with the highest yield. The identification and quantification of the crude anthocyanins were carried out using HPLC-DAD. The highest crude anthocyanin yield of 19.92% was observed by HCl acidified ethanol extract Acetic acid/water/methanol extract produced the lowest yield of 8.72%. The stability results showed that pigment retention of samples heated at 80˚C had a greater decrease over time than those heated at 50˚C. The pH stability of samples incubated for 7 days indicated that crude anthocyanins degraded slower at acidic pH, which is in keeping with reported literature therefore this extract, should be added to foods with lower pH. Light stability showed slower degradation in dark incubated samples resulting in 84% pigment retention after a 10 day period. Synthetic colourants proved to be superior, as they had showed better stability than the natural colourant under the same conditions. Half-life of thermally treated samples showed a decrease upon heating, colour was also affected as samples became dull and murky. DPPH of thermal treated samples showed a decline in radical scavenging activity from 70 to 85˚C and thereafter an increase was observed between 85 and 90˚C, this could be due to the release of degradation products that have antioxidant capability. Solvent systems did not have an effect on the total phenolic content of crude extracts as no significant difference was observed by each of the H. sabdariffa crude extracts contained an average of 54.67 mg/ml GAE. The radical scavenging ability assessed by the DPPH and FRAP assays showed 53.75% and 57.51% radical scavenging ability respectively. Although the synthetic colourants showed better stability, a natural food colourant from H. sabdariffa can still be beneficial as it has potential to be applied into foods that contain low pH such as jelly and yoghurt. The additional benefits that natural food colourants possess aid in the marketability of the product. / M

No description available.

published_or_final_version / Botany / Doctoral / Doctor of Philosophy

Thesis (Ph. D.)--University of Hong Kong, 2002. / Includes bibliographical references.

Yeung Kit Ying. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 98-106). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / List of Abbreviations --- p.iv / List of Tables --- p.v / List of Figures --- p.vi / Chapter 1 --- Introduction / Chapter 1.1 --- Botany --- p.1 / Chapter 1.2 --- Food additives and food preservation --- p.2 / Chapter 1.2.1 --- Lipid peroxidation --- p.2 / Chapter 1.2.2 --- Role of food antioxidant --- p.4 / Chapter 1.2.3 --- Microbial spoilage --- p.5 / Chapter 1.2.4 --- Additives in future --- p.6 / Chapter 1.3 --- Antioxidant and health benefits effects --- p.7 / Chapter 1.4 --- Measurement of antioxidants --- p.7 / Chapter 1.4.1 --- Trolox equivalent antioxidant capacity (TEAC) assay --- p.8 / Chapter 1.4.2 --- DPPH radical scavenging assay --- p.9 / Chapter 1.4.3 --- β-carotene bleaching assay --- p.9 / Chapter 1.4.4 --- Assay for erythrocyte hemolysis mediated by peroxyl free radicals --- p.10 / Chapter 1.4.5 --- Measurement of lipid peroxidation in foods --- p.10 / Chapter 1.5 --- Antiproloiferative studies --- p.12 / Chapter 1.5.1 --- MTT assay --- p.12 / Chapter 1.5.2 --- Cell Proliferation ELISA-BrdU (chemiluminescence) assay --- p.13 / Chapter 1.5.3 --- Cytotoxicity detection assay (LDH) --- p.13 / Chapter 1.6 --- Characterization of phenolic compounds --- p.14 / Chapter 1.6.1 --- Sephadex column chromatography --- p.14 / Chapter 1.6.2 --- Folin and Ciocalteu's assay --- p.15 / Chapter 1.7 --- Research objectives --- p.15 / Chapter 2 --- Materials and Methods / Chapter 2.1 --- Standards and reagents --- p.22 / Chapter 2.2 --- Plant materials --- p.23 / Chapter 2.3 --- Pigment preparation --- p.23 / Chapter 2.4 --- Determination of antioxidant activity --- p.25 / Chapter 2.4.1 --- Trolox equivalent antioxidant capacity (TEAC) assay --- p.25 / Chapter 2.4.2 --- DPPH. radical scavenging assay --- p.26 / Chapter 2.4.3 --- β-carotene bleaching assay --- p.26 / Chapter 2.4.4 --- Assay for erythrocyte hemolysis mediated by peroxyl free radicals --- p.27 / Chapter 2.4.4.1 --- Determination of IC50 --- p.28 / Chapter 2.5 --- Evaluation of CP as antioxidant in various food models --- p.28 / Chapter 2.5.1 --- Preparation of food samples --- p.28 / Chapter 2.5.2 --- Butter cookies --- p.29 / Chapter 2.5.3 --- Salad dressing --- p.29 / Chapter 2.5.4 --- Fried potato chips --- p.29 / Chapter 2.5.5 --- PeroXOquant´ёØ quantitative peroxide assay --- p.29 / Chapter 2.5.6 --- Statistical analysis --- p.30 / Chapter 2.6 --- Determination of antimicrobial activity --- p.31 / Chapter 2.6.1 --- Determination of antimicrobial activity --- p.31 / Chapter 2.6.1.1 --- Bacterial stock --- p.31 / Chapter 2.6.1.2 --- Preparation of nutrient agar plate --- p.31 / Chapter 2.6.1.3 --- Minimal inhibiting concentration (MIC) --- p.31 / Chapter 2.6.2 --- Determination of antifungal activity --- p.32 / Chapter 2.6.2.1 --- Fungi stock --- p.32 / Chapter 2.6.2.2 --- Preparation of potato dextrose agar plates --- p.32 / Chapter 2.6.2.3 --- Growth inhibition effect --- p.32 / Chapter 2.6.3 --- Statistical analysis --- p.33 / Chapter 2.7 --- In vitro effect on human cell lines --- p.34 / Chapter 2.7.1 --- Cell lines --- p.34 / Chapter 2.7.2 --- Maintenance of cell lines --- p.34 / Chapter 2.7.3 --- MTT assay --- p.35 / Chapter 2.7.4 --- Cell Proliferation ELISA-BrdU (chemiluminescence) assay --- p.36 / Chapter 2.7.5 --- Determination of IC50 --- p.37 / Chapter 2.7.6 --- Cytotoxicity detection assay --- p.37 / Chapter 2.7.6.1 --- Optimal cell concentration --- p.37 / Chapter 2.7.6.2 --- LDH detection assay --- p.38 / Chapter 2.7.7 --- Statistical analysis --- p.39 / Chapter 2.8 --- Fractionation and characterization --- p.40 / Chapter 2.8.1 --- Sephadex column chromatography --- p.40 / Chapter 2.8.2 --- Fourier transform infrared (FT-IR) spectra --- p.40 / Chapter 2.8.3 --- Folin and Ciocalteu's assay --- p.40 / Chapter 2.8.4 --- Statistical analysis --- p.41 / Chapter 3 --- Results / Chapter 3.1 --- Determination of antioxidant activity --- p.43 / Chapter 3.1.1 --- Trolox equivalent antioxidant capacity (TEAC) assay --- p.43 / Chapter 3.1.2 --- DPPH.radical scavenging assay --- p.43 / Chapter 3.1.3 --- β-carotene bleaching assay --- p.44 / Chapter 3.1.4 --- Assay for erythrocyte hemolysis mediated by peroxyl free radicals --- p.44 / Chapter 3.2 --- Potential application as food antioxidant --- p.45 / Chapter 3.2.1 --- Peroxide standard curve --- p.45 / Chapter 3.2.2 --- Inhibition of lipid peroxidation in different food items --- p.45 / Chapter 3.3 --- Potential application as food preservative --- p.46 / Chapter 3.3.1 --- Antibacterial activity --- p.46 / Chapter 3.3.2 --- Antifungal activity --- p.46 / Chapter 3.4 --- In vitro effect on human cell lines --- p.47 / Chapter 3.4.1 --- Effect on the growth of human cancer cells --- p.47 / Chapter 3.4.2 --- Antiproliferative effect on selected human cancer cells --- p.48 / Chapter 3.4.3 --- Cytotoxicity effect on selected human cancer cells and normal fibroblast --- p.48 / Chapter 3.4.3.1 --- Optimal cell density for cytotoxicity determined assay --- p.48 / Chapter 3.4.3.2 --- Cytotoxic effect --- p.48 / Chapter 3.5 --- Fractionation and characterization --- p.49 / Chapter 3.5.1 --- Percentage of yield --- p.49 / Chapter 3.5.2 --- Fourier transform infrared (FT-IR) spectra --- p.49 / Chapter 3.5.3 --- Determination of total phenolic content --- p.49 / Chapter 3.5.4 --- Determination of antioxidant activity --- p.50 / Chapter 3.5.5 --- Relationship between total phenolics and antioxidant activity --- p.50 / Chapter 3.5.6 --- Antiproliferative effect on cancer cell --- p.50 / Chapter 3.5.7 --- Cytotoxic effect --- p.51 / Chapter 3.5.7.1 --- HepG2 human cancer cell line --- p.51 / Chapter 3.5.7.2 --- Hs68 human normal fibroblast --- p.51 / Chapter 4 --- Discussion / Chapter 4.1 --- Application of CP as a natural food additive with multi-functions --- p.87 / Chapter 4.1.1 --- CP as a natural food antioxidant --- p.88 / Chapter 4.1.2 --- CP as a natural food preservative --- p.90 / Chapter 4.2 --- Potential health-beneficial --- p.91 / Chapter 4.2.1 --- CP as dietary antioxidant --- p.91 / Chapter 4.2.2 --- Antiproliferative activity of CP --- p.92 / Chapter 4.3 --- Further characterization of CP --- p.94 / Chapter 4.4 --- Future perspectives --- p.96 / Chapter 5 --- Conclusion --- p.97 / References --- p.98