Yeasts In Food And Beverages

As a group of microorganisms, yeasts have an enormous impact on food and bev- age production. Scientific and technological understanding of their roles in this p- duction began to emerge in the mid-1800s, starting with the pioneering studies of Pasteur in France and Hansen in Denmark on the microbiology of beer and wine fermentations. Since that time, researchers throughout the world have been engaged in a fascinating journey of discovery and development – learning about the great diversity of food and beverage commodities that are produced or impacted by yeast activity, about the diversity of yeast species associated with these activities, and about the diversity of biochemical, physiological and molecular mechanisms that underpin the many roles of yeasts in food and beverage production. Many excellent books have now been published on yeasts in food and beverage production, and it is reasonable to ask the question – why another book? There are two different approaches to describe and understand the role of yeasts in food and beverage production. One approach is to focus on the commodity and the technology of its processing (e. g. wine fermentation, fermentation of bakery products), and this is the direction that most books on food and beverage yeasts have taken, to date. A second approach is to focus on the yeasts, themselves, and their bi- ogy in the context of food and beverage habitats.

Yeasts play a crucial role in the sensory quality of a wide range of foods. They can also be a major cause of food spoilage. Maximising their benefits whilst minimising their detrimental effects requires a thorough understanding of their complex characteristics and how these can best be manipulated by food processors. Yeasts in food begins by describing the enormous range of yeasts together with methods for detection, identification and analysis. It then discusses spoilage yeasts, methods of control and stress responses to food preservation techniques. Against this background, the bulk of the book looks at the role of yeasts in particular types of food. There are chapters on dairy products, meat, fruit, bread, soft drinks, alcoholic beverages, soy products, chocolate and coffee. Each chapter describes the diversity of yeasts associated with each type of food, their beneficial and detrimental effects on food quality, methods of analysis and quality control. With its distinguished editors and international team of over 30 contributors, Yeasts in food is a standard reference for the food industry in maximising the contribution of yeasts to food quality. Describes the enormous range of yeasts together with methods for detection, identification and analysis Discusses spoilage yeasts, methods of control and stress responses to food preservation techniques Examines the beneficial and detrimental effects of yeasts in particular types of food, including dairy products, meat, fruit, bread, soft drinks, alcoholic beverages, soy products, chocolate and coffee

Far more than a simple update and revision, the Handbook of Food Spoilage Yeasts, Second Edition extends and restructures its scope and content to include important advances in the knowledge of microbial ecology, molecular biology, metabolic activity, and strategy for the prohibition and elimination of food borne yeasts. The author incorporates new

I belie ve that the book would provide an overview of the recent developments in the domain of yeast research with some new ideas, which could serve as an inspiration and challenge for researchers in this field. Ne w Delhi Prof. Asis Datta Dec. 24, 2007 F ormer Vice-chancellor, JNU Director, NCPGR (New Delhi) Pr eface Yeasts are eukaryotic unicellular microfungi that are widely distributed in the natural environments. Although yeasts are not as ubiquitous as bacteria in the na- ral environments, they have been isolated from terrestrial, aquatic and atmospheric environments. Yeast communities have been found in association with plants, a- mals and insects. Several species of yeasts have also been isolated from specialized or extreme environments like those with low water potential (e. g. high sugar/salt concentrations), low temperature (e. g. yeasts isolated from Antarctica), and low oxygen availability (e. g. intestinal tracts of animals). Around 1500 species of yeasts belonging to over 100 genera have been described so far. It is estimated that only 1% of the extant yeasts on earth have been described till date. Therefore, global efforts are underway to recover new yeast species from a variety of normal and extreme environments. Yeasts play an important role in food chains, and carbon, nitrogen and sulphur cycles. Yeasts can be genetically manipulated by hybridization, mutation, rare m- ing, cytoduction, spheroplast fusion, single chromosomal transfer and transfor- tion using recombinant technology. Yeasts (e. g.

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.

It is well established that certain strains of yeasts are suitable for transforming grape sugars into alcohol, while other yeast strains are not suitable for grape fermentations. Recent progress has clearly demonstrated that the sensory profile of a wine is characteristic of each vine cultivated, and the quality and technological characteristics of the final product varies considerably due to the strains which have performed and/or dominated the fermentation process. Because of their technological properties, wine yeast strains differ significantly in their fermentation performance and in their contribution to the final bouquet and quality of wine, such as useful enzymatic activities and production of secondary compounds related both to wine organoleptic quality and human health. The wine industry is greatly interested in wine yeast strains with a range of specialized properties, but as the expression of these properties differs with the type and style of wine to be made, the actual trend is in the use of selected strains, which are more appropriate to optimize grape quality. Additionally, wine quality can be influenced by the potential growth and activity of undesirable yeast species, considered spoilage yeasts, which cause sluggish and stuck fermentation and detrimental taste and aroma in the wine.

Did you know? It's estimated that fermentation practices have been around since as early as 6000 BC, when wine was first being made in Caucasus and Mesopotamia. Today, there are roughly 5000 varieties of fermented foods and beverages prepared and consumed worldwide, which accounts for between five and forty percent of daily meals. Fermented Foods a

Yeasts are the active agents responsible for three of our most important foods - bread, wine, and beer - and for the almost universally used mind/ personality-altering drug, ethanol. Anthropologists have suggested that it was the production of ethanol that motivated primitive people to settle down and become farmers. The Earth is thought to be about 4. 5 billion years old. Fossil microorganisms have been found in Earth rock 3. 3 to 3. 5 billion years old. Microbes have been on Earth for that length of time carrying out their principal task of recycling organic matter as they still do today. Yeasts have most likely been on Earth for at least 2 billion years before humans arrived, and they playa key role in the conversion of sugars to alcohol and carbon dioxide. Early humans had no concept of either microorganisms or fermentation, yet the earliest historical records indicate that by 6000 B. C. they knew how to make bread, beer, and wine. Earliest humans were foragers who col lected and ate leaves, tubers, fruits, berries, nuts, and cereal seeds most of the day much as apes do today in the wild. Crushed fruits readily undergo natural fermentation by indigenous yeasts, and moist seeds germinate and develop amylases that produce fermentable sugars. Honey, the first con centrated sweet known to humans, also spontaneously ferments to alcohol if it is by chance diluted with rainwater. Thus, yeasts and other microbes have had a long history of 2 to 3.

The Yeasts: A Taxonomic Study is a three-volume book that covers the taxonomic aspect of yeasts. The main goal of this book is to provide important information about the identification of yeasts. It also discusses the growth tests that can be used to identify different species of yeasts, and it examines how the more important species of yeasts provide information for the selection of species needed for biotechnology. • Volume 1 discusses the identification, classification and importance of yeasts in the field of biotechnology. • Volume 2 focuses on the identification and classification of ascomycetous yeasts. • Volume 3 deals with the identification and classification of basidiomycetous yeasts, along with the genus Prototheca. High-quality photomicrographs and line drawings Detailed phylogenetic trees Up-to-date, clearly presented yeast taxonomy and systematic, easy-to-use reference sequence accession numbers to allow for correct identification

Health Benefits of Fermented Foods and Beverages discusses the functionality and myriad health benefits of fermented foods and beverages of the world. It examines health-promoting and therapeutic properties, covering the molecular process of fermentation and the resulting benefit to nutritional value and long-term health. Exploring a range of ferme