Handbook on Sourdough Biotechnology

Description

Bread and leavened bakery products have been essential to human nourishment for millennia. Traditionally, bread production has relied on the use of sourdough as a leavening agent and to impart a characteristic quality to baked goods. In recent years, improved understanding of the biodiversity and microbial ecology of sourdough microbiota, the discovery of new species, the improved management and monitoring of its meta-community and the commercialization of innovative products have vastly expanded the potential of sourdough fermentation for making baked goods. For example, raw materials such as cereals, pseudo-cereals, ancient grains, and gluten-free substrates, as well as a large number of baked good varieties (e.g., typical and industrial breads, sweet baked goods, gluten-free products) may benefit from advances in sourdough fermentation. In addition, biotechnological tools and culture properties have been discovered to improve both the shelf life and the sensory and textural qualities of baked goods, as well as their nutritional and health-promoting properties. Now in its second edition, the Handbook on Sourdough Biotechnology remains the only book dedicated completely to sourdough biotechnology with the contribution of the most experienced researchers from the field. It reviews the history of sourdough and the potential of sourdough fermentation in the production of bread and baked goods. A thorough discussion of the various processing steps includes the chemical properties of the raw matter, the taxonomy, diversity, and metabolic properties of starter yeasts and lactic acid bacteria, and the effects of sourdough fermentation on the shelf life and the sensory, textural, nutritional, and health-promoting properties of baked goods. Contents 1: History and Social Aspects of Sourdough 1.1 Sourdough: The Ferment of Life 1.2 History and Social Aspects of Sourdough in France 1.3 History and Social Aspects of Sourdough in Italy 1.4 History and Social Aspects of Sourdough in Germany 1.5 Global History 1.6 Recent Developments References 2: Sourdough in a Regulatory Context 2.1 Sourdough as a Subject of Food Law 2.2 National Regulations 2.2.1 Austria 2.2.2 Germany 2.2.3 France 2.2.4 Spain 2.2.5 Czech Republic 2.2.6 Netherlands 2.2.7 Codes of Practice 2.3 Protected Geographical Indication (PGI) and Traditional Specialty Guaranteed (TSG) References 3: Chemistry of Cereal Grains 3.1 Introductory Remarks 3.2 Grain Morphology and Chemical Composition 3.3 Carbohydrates 3.3.1 Starch 3.3.1.1 Changes in Starch Structure During Processing 3.3.1.2 Digestion of Starch as Affected by Structural Features 3.3.2 Nonstarch Polysaccharides (NSP) 3.3.2.1 Arabinoxylans 3.3.2.2 Other Non-starch Polysaccharides 3.4 Proteins 3.4.1 Storage Proteins 3.4.1.1 Wheat, Rye, Barley, and Oats Storage Proteins 3.4.1.2 Wheat Gluten 3.4.2 Storage Proteins of Maize, Millet, Sorghum, and Rice 3.4.3 Metabolic Proteins: Enzymes and Enzyme Inhibitors 3.5 Lipids 3.5.1 Lipid Composition 3.5.2 Effects of Lipids on the Baking Performance of Wheat Flour 3.6 Minor Constituents 3.6.1 Minerals 3.6.2 Vitamins 3.6.3 Bioactive Compounds or Phytochemicals 3.6.4 Antinutrients Appendix References 4: Technology of Sourdough Fermentation and Sourdough Application 4.1 Fermentation Schemes 4.1.1 Rye Processing 4.1.1.1 Industrial Nordic Rye Sourdoughs 4.1.1.2 Industrial Rye Sourdough Types High Dry Matter Type 1 Sourdough (Firm Sourdough) Low Dry Matter Industrial Sourdoughs (Liquid, Pumpable Sourdough) Rye Sourdough Bread Making 4.1.2 Wheat Processing 4.2 Mother Dough 4.2.1 Development of Mother Dough by Spontaneous Fermentation 4.2.2 Cereal Based Sourdough Starters Obtained by Back-slopping 4.2.3 Dried Sourdoughs with Active Cultures 4.2.4 Freeze-Dried Cultures 4.3 Dried Sourdoughs 4.3.1 Ready-to-Use Industrial Sourdough 4.3.2 Spray-Dried and Drum-Dried Ready-to-Use Sourdoughs 4.4 The Future of Industrial Bread References 5: Steamed Bread 5.1 Introduction 5.2 Types of Steamed Bread 5.2.1 Northern-Style Steamed Bread 5.2.2 Southern-Style Steamed Bread 5.2.3 Cantonese-Style Steamed Bread 5.2.4 Differences in Ingredients of the Three Types of Steamed Bread 5.2.5 Differences in Physical Properties 5.3 Process for Steamed Bread Preparation 5.3.1 Sourdough Procedure 5.3.2 Dough Preparation Procedures 5.3.3 Microbiology of Traditional Chinese Sourdoughs 5.3.4 Control of Proofing Conditions 5.3.5 Steaming 5.3.6 Cooling and Packing 5.3.7 Quick-Frozen Steamed Bread 5.4 Effect of Sourdough on Steamed Bread Quality 5.4.1 Texture 5.4.2 Volatile Compounds 5.4.3 Shelf Life References 6: Taxonomy and Species Diversity of Sourdough Lactic Acid Bacteria 6.1 Taxonomy of Sourdough Lactic Acid Bacteria 6.1.1 Phylogenetic Position of Lactic Acid Bacteria 6.1.2 Classification of Lactobacillaceae 6.1.3 Occurrence and Identification of Lactobacillaceae in Sourdoughs 6.1.4 Lactobacillaceae Species First Isolated from Sourdough 6.1.5 Pediococcus, Leuconostoc, and Weissella as Subdominant Lactic Acid Bacteria Sourdough Species 6.2 Isolation of Sourdough Lactic Acid Bacteria 6.3 Identification of Sourdough Lactic Acid Bacteria 6.3.1 Culture-Dependent Approaches 6.3.1.1 Phenotypic Identification 6.3.1.2 Chemotaxonomic Identification 6.3.1.3 DNA Fingerprint-Based Molecular Identification 6.3.1.4 DNA Sequence-Based Molecular Identification 6.3.2 Culture-Independent Approaches 6.3.2.1 Oligonucleotide Probe/Primer-Based Identification 6.3.2.2 Whole-Community DNA Fingerprinting Identification 6.3.2.3 Metagenetic (PCR Amplicon)-Based Identification 6.3.2.4 Microarray-Based Metatranscriptomics 6.3.2.5 Sequencing-Based Metatranscriptomics 6.3.2.6 Metagenomics 6.3.2.7 Whole-Genome Sequencing 6.4 Meta-Analysis of the Species Diversity of Sourdough Lactic Acid Bacteria 6.5 Factors Influencing the Lactic Acid Bacterial Species Diversity of Sourdoughs 6.5.1 Influence of Geography 6.5.1.1 The Origin of Sourdough and the Sourdough-Specific Lactic Acid Bacterial Species Fructilactobacillus sanfranciscensis 6.5.1.2 The Origin of Sourdough Variation 6.5.1.3 Region-Specific Sourdoughs and Their Associated Microbiota 6.5.1.4 Influence of Cereals and Other Raw Materials 6.5.1.5 Influence of Technology Sourdough Processing Functional Starter Cultures Fermentation Temperature Acidity Dough Yield Oxygen Tension Backslopping Parameters Microbial Interactions References 7: Taxonomy, Biodiversity, and Physiology of Sourdough Yeasts 7.1 Introduction 7.2 Yeast Taxonomy 7.2.1 Defining Yeast Taxa 7.2.2 Identifying Yeast Species in Sourdough 7.3 Yeasts Species Diversity 7.3.1 Yeast Species Detected in Sourdoughs 7.3.2 Geographical Distribution of Yeast Species Across Sourdoughs 7.4 Yeast Dispersion Across Environments 7.4.1 Dispersion Vectors 7.4.2 Origin of Sourdough Yeast Species 7.5 Abiotic Factors Influencing Yeast Species Diversity in Sourdoughs 7.5.1 Cereal Species 7.5.2 Bakery Practices 7.5.2.1 Scale of Production 7.5.2.2 Temperature 7.5.2.3 Hydration Rate 7.5.2.4 Time Between Back-Slopping and Re-feeding Practices 7.6 Yeasts Evolution in Sourdough 7.6.1 Intraspecific Diversity in Sourdough and the Selection of a New Starter 7.6.2 Domestication of S. cerevisiae for Bread-Making 7.6.3 Yeast–LAB and Yeast–Yeast Interactions 7.6.3.1 Co-occurrence and Facilitation 7.6.3.2 Metabolism 7.6.4 Yeast/Yeast Interactions 7.7 Physiology and Biochemistry of Sourdough Yeasts 7.7.1 The Yeast Nitrogen Metabolism 7.7.2 The Yeast Carbohydrate Metabolism 7.7.3 Stress Response in Sourdough Yeasts 7.7.3.1 Low Temperature 7.7.3.2 Acidity 7.7.3.3 Osmotic Stress 7.7.3.4 Membrane Lipids as Modulators of Stress Tolerance in Yeasts 7.7.4 Secondary Yeast Metabolites in Sourdough 7.8 Baker’s Yeast in the Bread-Making Industry 7.8.1 Baker’s Yeast Production 7.8.1.1 Raw Materials 7.8.1.2 Fermentation 7.8.2 General Characteristics of Fresh and Dry Baker’s Yeast 7.8.2.1 Fresh Baker’s Yeast 7.8.2.2 Dry Baker’s Yeast References 8: Physiology and Biochemistry of Sourdough Lactic Acid Bacteria and Their impact on Bread Quality 8.1 Introduction 8.2 General Growth and Stress Parameters 8.3 Metabolism of Carbohydrates 8.3.1 Use of External Acceptors of Electrons 8.3.2 Metabolism of Organic Acids 8.3.3 Preferential and/or Simultaneous Use of Energy Sources 8.3.4 Metabolism of Oligosaccharides 8.4 Proteolysis and Catabolism of Free Amino Acids 8.4.1 Proteolysis 8.4.2 Amino Acid Metabolism 8.4.3 Synthesis of Kokumi-Active Peptides 8.5 Synthesis of Exopolysaccharides 8.5.1 EPS Biosynthesis and HoPS Structure 8.5.2 Ecological Function of HoPS Production and HoPS Formation in Dough 8.6 Antimicrobial Compounds from Sourdough Lactic Acid Bacteria 8.6.1 Antifungal Compounds from Sourdough Lactic Acid Bacteria 8.6.2 Antibacterial Compounds from Sourdough Lactic Acid Bacteria 8.7 Metabolism of Phenolic Compounds and Lipids 8.8 Metabolism of Sourdough Metacommunities References 9: Sourdough: A Tool for Non-conventional Fermentations and to Recover Side Streams 9.1 Introduction 9.2 By-Products and Surplus from the Cereal Industry 9.2.1 Side-Streams Generation 9.2.2 Re-use and Valorization of Milling By-Products Through Fermentation 9.2.2.1 Wheat Bran 9.2.2.2 Wheat Germ 9.2.2.3 Rye Bran 9.2.2.4 Rice Germ and Bran 9.2.2.5 Milling By-Products from Other Cereals 9.3 Fermentation of the Cereal Industry Waste 9.3.1 Brewers’ Spent Grain 9.3.2 Surplus and Waste Bread 9.4 Fermentation of Legumes and Pseudo-cereals 9.4.1 Legumes 9.4.1.1 Nutritional Properties and Anti-nutritional Factors Issue 9.4.1.2 Sourdough Fermentation and Baked Goods Fortification 9.4.2 Pseudo-cereals 9.4.2.1 Nutritional and Functional Features 9.4.2.2 Potential of the Sourdough Fermentation Applied to Pseudo-cereals References 10: Nutritional Aspects of Cereal Fermentation with Lactic Acid Bacteria and Yeast 10.1 Introduction 10.2 Effects on Cereal Biopolymers 10.2.1 Starch and Glycemic Index 10.2.2 Protein 10.2.3 Biogenic Peptides 10.2.4 Protein Digestibility 10.2.5 Dietary Fiber 10.2.6 Antinutritional Factors 10.3 Micronutrients 10.3.1 Vitamins 10.3.2 Minerals 10.3.3 Phytochemicals 10.4 Microbial Exopolysaccharides 10.5 Sourdough and Gut Microbiota 10.6 Future Prospects References 11: Sourdough and Gluten-Free Products 11.1 Introduction: Gluten-Free Cereal Products 11.2 Sourdough Bread 11.3 Ecology of GF Fermentations and Development of GF Sourdough Starters 11.4 Proteolysis as a Tool to Improve the Baking Performances of GF Flours 11.5 Proteolysis for Reducing the Toxicity of Wheat Flour 11.6 Application of Legume-Based Flours for GF Bread 11.7 FODMAPs and GF Products 11.8 Exopolysaccharides: A Low-Cost Alternative to Hydrocolloids in GF Breads 11.9 Starch Hydrolysis for Delaying the Staling of GF Bread 11.10 Sourdough as a Natural Tool for Improving the Shelf Life of GF Bread 11.11 Sourdough Fermentation for Enhancing the Health Benefits of GF Bread 11.12 Germination and Sourdough Fermentation for the Development of GF Products 11.13 Conclusions References 12: Sourdough and Cereal Beverages 12.1 Introduction 12.2 Boza 12.3 Togwa and Mahewu 12.4 Bushera 12.5 Gowé 12.6 Kwete 12.7 Malwa 12.8 Koko Sour Water 12.9 Pozol 12.10 Chicha 12.11 Kishk 12.12 Kvass 12.13 Sourish Shchi 12.14 Hulu-mur and Abreh 12.14.1 Abreh 12.15 Fermented Cereal Beverages with Live Microbiota References 13: Perspectives 13.1 Microbial Ecology of Sourdough 13.2 Sourdough and Product Quality 13.3 Sourdough and Nutrition 13.4 Industrial and Artisanal Use of Sourdough References Index