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Book Details
Abstract
The popularity of the plant Stevia (Stevia rebaudiana) has risen due to increasing use and interest in its sweet constituents called steviol glycosides. In recent years, these have been approved all over the world as food additives in the category of sweetener, hence they have received more attention and their use in food formulations has increased significantly. New techniques in growing stevia have resulted in new varieties with interesting steviol glycoside profiles. Also, new techniques to analyse the content of sweeteners in different matrices and the detection of new steviol glycosides with very pleasant sensory profiles has followed. The aim of this book is to present novel uses and manufacturing developments as well as to gather together up-to-date information across the whole developing area of steviol glycosides research.
Dr.Ursula Wölwer-Rieck graduated in Food Chemistry and has a PhD in natural sciences. Her academic research is focused on the plant Stevia rebaudiana and its constituents, mainly on steviol glycosides. She has published several papers and given lectures on the analysis of steviol glycosides, their stability in food and further constituents of the plant. She is also a board member of the European Stevia Association (EUSTAS) whose petition for steviol glycosides led to their approval as food additives in Europe in 2011 and a member of the advisory board of the Global Stevia Institute.
Table of Contents
| Section Title | Page | Action | Price |
|---|---|---|---|
| Cover | Cover | ||
| Steviol Glycosides: Cultivation, Processing, Analysis and Applications in Food | i | ||
| Preface | v | ||
| Contents | vii | ||
| Chapter 1 - Crop and Steviol Glycoside Improvement in Stevia by Breeding | 1 | ||
| 1.1 Introduction | 1 | ||
| 1.2 Objectives of Stevia Selection and Breeding | 2 | ||
| 1.2.1 Dry Leaf Yield per Plant and Unit Area | 2 | ||
| 1.2.2 Leaf-to-stem Ratio | 3 | ||
| 1.2.3 Growth and Photosynthetic Activity | 3 | ||
| 1.2.4 Wider Crop Adaptability, Yield Stability and Abiotic Stress Resistance | 3 | ||
| 1.2.5 Biotic Stress Resistance | 4 | ||
| 1.2.6 Photoperiod Insensitivity | 4 | ||
| 1.2.7 Self-compatibility for Viable Seed Production | 5 | ||
| 1.2.8 Steviol Glycoside Composition and Yield | 5 | ||
| 1.2.8.1 Higher Steviol Glycosides Content in the Leaves | 5 | ||
| 1.2.8.2 Higher Content of Specific Glycosides | 5 | ||
| 1.2.8.3 Higher Content of Specific Not-steviol Glycosides Compounds | 6 | ||
| 1.3 Variability of Steviol Glycosides Content and Composition in Stevia Leaves | 11 | ||
| 1.3.1 Source of Variation | 11 | ||
| 1.3.2 Phenotypic and Genetic Variation in S. rebaudiana: The Genetic Control of SVgly Composition | 11 | ||
| 1.3.3 Character Association and Heritability in S. rebaudiana | 14 | ||
| 1.4 The Chromosome Number in Stevia Genus | 14 | ||
| 1.5 Plant Breeding Programs in Stevia | 15 | ||
| 1.5.1 Selection Programs in Stevia | 16 | ||
| 1.5.2 Recurrent Selection | 17 | ||
| 1.5.3 Synthetic Cultivars | 17 | ||
| 1.5.4 Changing the Number of Chromosomes in Plant Cells | 18 | ||
| 1.5.4.1 Polyploid Breeding | 18 | ||
| 1.5.4.2 Anther Culture | 19 | ||
| 1.5.5 Marker-assisted Selection | 19 | ||
| 1.5.6 New Biotechnological Tools | 20 | ||
| 1.5.6.1 Random Mutagenesis | 20 | ||
| 1.5.6.2 Site-directed Mutagenesis | 21 | ||
| 1.5.6.3 Transgenic Plants | 22 | ||
| 1.5.6.4 Agrobacterium Mediated Gene Transfer | 22 | ||
| 1.5.6.5 Agrobacterium Mediated Transient Gene Silencing (AMTS) | 23 | ||
| 1.6 Conclusions | 23 | ||
| References | 24 | ||
| Chapter 2 - Biosynthesis of Steviol Glycosides and Related Diterpenes in Leaves and Glandular Trichomes of Stevia rebaudiana Bertoni | 32 | ||
| 2.1 Introduction | 32 | ||
| 2.2 Morphology of Stevia rebaudiana Bertoni | 34 | ||
| 2.2.1 Foliar Trichomes of Stevia rebaudiana Bertoni | 35 | ||
| 2.2.1.1 Isolation Techniques for Trichomes | 39 | ||
| 2.3 Biosynthesis of Steviol Glycosides | 41 | ||
| 2.3.1 UDP-glycosyltransferases in Stevia rebaudiana | 43 | ||
| 2.3.2 MVA or DXP Pathway | 45 | ||
| 2.3.3 Site of Biosynthesis | 48 | ||
| 2.4 HS-SPME-GC-MS and LC-MS/MS-analysis of Foliar Trichomes and Exudates | 50 | ||
| 2.4.1 HS-SPME-GC-MS | 50 | ||
| 2.4.2 LC-MS/MS | 52 | ||
| 2.5 Outlook | 53 | ||
| References | 53 | ||
| Chapter 3 - Steviol Glycosides Production: Traditional Versus New Technologies | 59 | ||
| 3.1 Introduction | 59 | ||
| 3.2 Steviol Glycosides Production Technologies | 60 | ||
| 3.2.1 Objectives | 61 | ||
| 3.2.2 Process Steps | 61 | ||
| 3.2.3 Steviol Glycosides Primary Extraction | 62 | ||
| 3.2.3.1 Alternative Primary Extraction Technologies | 64 | ||
| 3.2.3.2 Discussion | 68 | ||
| 3.2.4 Steviol Glycosides Separation | 70 | ||
| 3.2.4.1 The Classical Process | 70 | ||
| 3.2.4.1.1\rSolvent Separation.In that alternative process, the flocculated clarified extract is separated in a continuous counter current l... | 71 | ||
| 3.2.4.1.2\rMembrane Filtration Technology.Some promising experiments have been done using membrane filtration to achieve steviol glycosides... | 71 | ||
| 3.2.4.1.3\rDiscussion.Whatever the process or the equipment used in this first part of production—extraction and separation of the steviol ... | 72 | ||
| 3.2.5 Steviol Glycosides Final Purification | 72 | ||
| 3.3 Alternative Steviol Glycosides Production Techniques | 74 | ||
| 3.3.1 Enzymatic Modification | 75 | ||
| 3.3.2 Genetic Engineering and Fermentation Techniques | 76 | ||
| 3.4 Production Technologies vs. Naturalness | 77 | ||
| 3.5 Conclusion | 78 | ||
| Acknowledgements | 79 | ||
| References | 80 | ||
| Chapter 4 - Analysis of Steviol Glycosides | 84 | ||
| 4.1 Introduction | 84 | ||
| 4.2 Sample Preparation | 87 | ||
| 4.2.1 Isolation of Steviol Glycosides from Leaves | 87 | ||
| 4.2.2 Isolation of Steviol Glycosides from Stevia Extract Preparation and Food | 89 | ||
| 4.3 Separation of Steviol Glycosides by High-performance Liquid Chromatography (HPLC) | 89 | ||
| 4.3.1 Separation on Normal Phase Columns | 90 | ||
| 4.3.1.1 Amino Columns | 90 | ||
| 4.3.1.2 Separation on Hydrophilic Interaction Liquid Chromatography (HILIC) Columns | 90 | ||
| 4.3.2 Separation on C18 columns | 92 | ||
| 4.3.3 Separation on Further Columns | 94 | ||
| 4.3.4 Separation Using Two-dimensional Systems | 94 | ||
| 4.4 Detection in HPLC | 95 | ||
| 4.4.1 UV-detection | 95 | ||
| 4.4.2 MS-detection | 95 | ||
| 4.4.3 Applying Alternative Detectors | 101 | ||
| 4.5 Alternative Techniques for Steviol Glycosides Determination | 102 | ||
| 4.5.1 Thin Layer (TLC) and High Performance Thin Layer Chromatography (HPTLC) | 102 | ||
| 4.5.2 Capillary Electrophoresis (CE) | 102 | ||
| 4.5.3 1H-NMR Spectroscopy | 104 | ||
| 4.5.4 Near-infrared Reflectance Spectroscopy (NIRS) | 104 | ||
| 4.5.5 Raman Spectroscopy | 104 | ||
| 4.5.6 Detection of Steviol Glycosides as Sum Parameter | 104 | ||
| 4.5.7 Detection of the Aglycon Steviol | 105 | ||
| 4.6 Conclusions | 106 | ||
| References | 106 | ||
| Chapter 5 - Presentation and Analysis of Other Constituents in the Leaves: Polyphenolics in Stevia rebaudiana Leaves | 113 | ||
| 5.1 Introduction | 113 | ||
| 5.1.1 Polyphenolics in Stevia | 114 | ||
| 5.1.1.1 Profiling of Polyphenolic Secondary Metabolites | 114 | ||
| 5.1.2 Quantification of Polyphenols in Stevia | 116 | ||
| 5.1.3 Further Lessons from Stevia Polyphenolic Analysis | 119 | ||
| 5.1.4 Plant Polyphenols and UV Exposure | 120 | ||
| 5.1.5 Correlation Analysis of Polyphenol Concentrations | 121 | ||
| 5.1.6 Multivariant Statistical Analysis of Stevia Phytochemical Profiles | 122 | ||
| Acknowledgement | 123 | ||
| References | 124 | ||
| Chapter 6 - Presentation and Analysis of Other Constituents in the Leaves: Analysis of Lipids and Volatile Terpenes in Stevia rebaudiana | 125 | ||
| 6.1 Introduction | 125 | ||
| 6.2 Analysis of Lipid Fraction | 126 | ||
| 6.2.1 Analysis of the Fatty Acid Profile | 126 | ||
| 6.2.2 Analysis of Intact Lipids | 128 | ||
| 6.2.3 Analysis of Terpenoid Lipophilic Volatiles | 129 | ||
| Acknowledgements | 131 | ||
| References | 131 | ||
| Chapter 7 - Antioxidant Capacity of Stevia Leaves | 132 | ||
| 7.1 Definition and Significance of Antioxidant Capacity for Food and Health | 132 | ||
| 7.1.1 Definition | 132 | ||
| 7.1.2 Significance of Antioxidant Capacity for Food | 133 | ||
| 7.1.3 Significance of Antioxidant Capacity for Health | 133 | ||
| 7.1.3.1 Direct Antioxidant Effect in the Organism | 134 | ||
| 7.1.3.2 Indirect Antioxidant Effect in the Organism | 134 | ||
| 7.2 Determination of Antioxidant Capacity | 135 | ||
| 7.2.1 Extraction of the Antioxidants | 135 | ||
| 7.2.2 Methods for Determination of Antioxidant Capacity | 135 | ||
| 7.2.2.1 Oxygen Radical Absorbance Capacity (ORAC) | 135 | ||
| 7.2.2.2 DPPH (2,2-Diphenyl-1-picrylhydrazyl) | 136 | ||
| 7.2.2.3 ABTS (2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) and TEAC (Trolox Equivalent Antioxidant Capacity) | 137 | ||
| 7.2.2.4 Folin–Ciocalteu | 138 | ||
| 7.2.2.5 FRAP (Ferric Reducing Antioxidant Power) | 139 | ||
| 7.2.3 Bioassays for the Determination of Antioxidant Capacity | 139 | ||
| 7.2.3.1 Antioxidant Enzymes | 140 | ||
| 7.2.3.2 Nucleic Acids | 140 | ||
| 7.2.3.3 Cell-based Antioxidant Capacity | 141 | ||
| 7.2.3.4 Lipid Peroxidation Inhibition | 143 | ||
| 7.2.3.5 In vivo Models | 144 | ||
| References | 145 | ||
| Chapter 8 - Stevia rebaudiana Bertoni: Beyond Its Use as a Sweetener. Pharmacological and Toxicological Profile of Steviol Glycosides of Stevia rebaudiana Bertoni | 148 | ||
| 8.1 Introduction | 148 | ||
| 8.2 Regulatory Committee Position | 149 | ||
| 8.3 Low Calorie Sweeteners | 149 | ||
| 8.4 The Pharmocokinetic Profile of SGs | 150 | ||
| 8.5 The Pharmacodynamic Profile of SGs | 150 | ||
| 8.6 Cardiovascular Benefits | 151 | ||
| 8.6.1 Antidiabetic Activity | 151 | ||
| 8.6.2 Antihypertensive Activity | 153 | ||
| 8.6.3 Cardioprotective Activity | 154 | ||
| 8.7 Non-cardiovascular Benefits of SGs | 154 | ||
| 8.7.1 Anticariogenic Activity | 155 | ||
| 8.7.2 Antimicrobial Activity | 155 | ||
| 8.7.3 Anticancer Activity | 156 | ||
| 8.7.4 Antioxidant and Anti-inflammatory Activity | 156 | ||
| 8.8 Toxic and Adverse Effects | 156 | ||
| References | 158 | ||
| Chapter 9 - Steviol Glycosides in Dentistry | 162 | ||
| 9.1 Introduction | 162 | ||
| 9.2 Oral Diseases | 163 | ||
| 9.3 Oral Biofilm/Dental Plaque | 164 | ||
| 9.4 Biofilm Management in Oral Diseases | 166 | ||
| 9.5 Steviol Glycosides in Dental Care | 167 | ||
| 9.5.1 Literature Overview | 167 | ||
| 9.5.2 Current Research | 172 | ||
| 9.5.3 Modulation of Bacterial Growth | 173 | ||
| 9.5.4 Effects of Steviol Glycosides on Bacterial Sugar Consumption and Acid Production | 174 | ||
| 9.5.5 Suppression of Oral Biofilm Formation | 178 | ||
| 9.5.6 Decomposition of Steviol Glycosides by Oral Bacteria | 180 | ||
| 9.6 Interaction of Steviol Glycosides to Oral Tissues | 181 | ||
| 9.7 Perspectives | 182 | ||
| References | 182 | ||
| Chapter 10 - Sensory Effects of Steviol Glycosides: Taste Perception and Beyond | 185 | ||
| 10.1 Introduction | 185 | ||
| 10.2 Taste Aspects of Steviol Glycosides and Their Interaction with the Sweet-taste Receptor | 186 | ||
| 10.2.1 Taste Perception | 186 | ||
| 10.2.2 Taste Receptors | 186 | ||
| 10.2.3 Taste Perception of Stevioside | 187 | ||
| 10.3 Steviol and Steviol Glycosides Act as a Taste Amplifier through Interaction with TRPM5 | 190 | ||
| 10.3.1 TRPM5 | 190 | ||
| 10.3.2 TRPM5 in Taste Sensation | 190 | ||
| 10.3.3 TRPM5 and Steviol Glycosides | 191 | ||
| 10.4 Anti-diabetic Effects of Steviol Glycosides through Their Interaction with TRPM5 | 192 | ||
| 10.4.1 Diabetes | 192 | ||
| 10.4.2 TRPM5 and Diabetes | 192 | ||
| 10.4.3 Steviol Glycosides and Diabetes | 193 | ||
| 10.5 Anti-hyperglycaemic Effects of Steviol Glycosides in Humans | 195 | ||
| 10.5.1 Studies with Healthy Volunteers | 195 | ||
| 10.5.2 Studies with Individuals Diagnosed with Type-2 Diabetes Mellitus | 195 | ||
| 10.6 Concluding Remarks | 199 | ||
| Acknowledgements | 200 | ||
| References | 200 | ||
| Subject Index | 204 |