Yeast biomass is an excellent source of proteins, nucleic acids, and vitamins. It has been produced and consumed in baked goods and other foods for thousands of years and offers significant advantages when compared to other potential new microbial protein sources. Use of Yeast Biomass in Food Production provides up-to-date information regarding the chemical composition and biochemistry of yeasts, discusses the biotechnological basis of yeast production and possibilities for influencing yeast biomass composition using new techniques in molecular biology. The book examines techniques for producing yeast protein concentrates (and isolates) while still retaining their functional properties and nutritive values, as well as the various uses for these materials and their derivatives in different branches of the food industry. Finally, the book explores possibilities for the production and industrial use of other yeast components, such as nucleic acids, nucleotides, cell wall polysaccharides, autolysates, and extracts. Food microbiologists and technologists, as well as biotechnologists, will discover that this book is an invaluable reference resource.
Table of Contents
PART I. INTRODUCTION. THE YEAST. General Survey. Classification of Yeasts. The Yeast Cell. Morphology of Yeasts. Yeasts as Highly Efficient Producers of Protein. CHEMICAL COMPOSITION AND BIOCHEMISTRY OF YEAST BIOMASS. General Aspects and Gross Composition. YEAST PRODUCTION. CELL REPRODUCTION. Budding. Sexual Reproduction. ENERGY-YIELDING METABOLISM. Glucose and Other Carbohydrates. Fatty Acids and Hydrocarbons. Reoxydation of Reduced Coenzymes. Anaerobic Energy Production. PHYSIOLOGY OF GROWTH. Modes of Growth. Coordination of Metabolism and Growth. KINETICS OF MICROBIAL CELL GROWTH. The Continuous Culture. ENVIRONMENTAL EFFECTS ON BIOMASS PRODUCTION. Effects of Temperature. Effect of pH Values. Effect of Dissolved Oxygen. The Effect of CO2 Content. The Effect of Medium Composition. GENETIC MODIFICATIONS OF YEAST. Mutations and Mutagenic Agents. Induced Genotype Changes in Yeast. The Genetic Manipulation of Industrial Yeast Strains. YEAST PRODUCTION ON CARBOHYDRATES. Production of Baker's Yeast. Brewer's Yeast. Wine Yeast. SCP PRODUCTION ON WHEY. Strain Selection. The Effect of Medium Composition. BIOMASS PRODUCTION ON DATE SYRUP. Effect of Date Syrup Concentration on Yeast Growth. Effect of Date Syrup Concentration on Biomass Yield and Protein Content. BIOMASS PRODUCTION ON ETHANOL. Amoco's Pure Culture Process. Linde AG Process. Strain Breeding. YEAST BIOMASS PRODUCTION ON OTHER SUBSTRATES. Methanol. Carbohydrate Containing Wastes and Waste Waters. Biomass Production on Potato Starch. Biomass Production on Oil and Fat. SPECIAL ASPECTS OF PRODUCING METHIONINE-RICH YEAST STRAINS. EXTRACTION OF YEAST PROTEINS, YEAST PROTEIN CONCENTRATES AND ISOLATES AND THEIR NUTRITIVE VALUE. INTRODUCTION. Cell Rupture. EXTRACTION OF PROTEINS. REFINING OF THE EXTRACTED RAW PROTEIN. REDUCTION OF NUCLEIC ACID CONTENT OF YEAST-PROTEIN. NUTRITIVE VALUE AND SAFETY OF YEAST PROTEIN. Estimation of Protein Quality. NUTRITIVE VALUE OF YEAST PROTEINS. Data Based on Bioassays. In Vitro Data on Yeast Protein Quality Based on Amino Acid Composition. THE SAFETY OF THE YEAST AND YEAST PROTEIN PREPARATIONS. Conclusions. CHANGES OF PROTEINS DURING EXTRACTION OF PROTEINS AND PROCESSING OF YEAST BIOMASS. The Effect of Heat Treatment. Effect of Alkaline pHs. Oxidation of Amino Acid Residues. Protein-Carbohydrate Interactions. Protein-Lipid Interactions. Yeast Autolysates and Their Production. INDEX. PART II. INTRODUCTION. References. FOOD USES OF WHOLE YEAST CELLS. Active Yeast. Food Uses of Inactive Dried Whole Yeast Cells. References. USE OF YEAST PROTEIN PREPARATIONS IN FOOD INDUSTRY. Functional Properties of Yeast Proteins. General Aspects. Functional Properties of Protein Preparations. Methods of Evaluation of Functional Properties. PRODUCTION OF YEAST PROTEIN PREPARATIONS. FUNCTIONAL PROPERTIES OF YEAST CONCENTRATES AND ISOLATES. Texturization of Yeast Proteins. Food Application of Yeast Protein Isolates and Concentrates. IMPROVEMENT OF FUNCTIONALITY BY PROTEIN MODIFICATION. Enzymatic Protein Modification. Chemical Modification of Proteins. References. USE OF YEAST AUTOLYSIS AND YEAST HYDROLYSATES IN FOOD PRODUCTION. Production of Yeast Autolysates. Practical Examples of Utilization of Yeast Autolysates and Hydrolysates. Appendix. OTHER USES OF YEAST BIOMASS. New Trends in Utilization of Yeast Biomass. Production and Applications of Yeast Enzymes. Nucleic Acids, Nucleotides, and Nucleosides. Vitamins. Other Compounds. Consumer Acceptability of Novel Protein Products. SUBJECT INDEX.