Yeast Culture in Baking
The advent of agriculture in many different human civilizations caused significant diet changes stapled by the consistent availability and thus predominating source of nutrients from cereals. In some areas, cereals total as much as 80% of total food intake (Food and Bread history). Microbes existing on the surfaces of many of these grains in some cases cause spoilage; however, some microbes such as Saccharomyces cerevisiae, or simply called yeast, aid in the process of breaking down complex, potentially detrimental grain macromolecules while increasing taste of the product. As grains have been the primary source of carbohydrates since the advent of agriculture, predating any empirical understanding of microbes, yeast culture in baking serves as an exciting point of academic inquiry at the intersection of cultural health, cultural traditions, and the molecular biological driving forces. The Yeast fermentation process is integral to their utililty, converting complex carbohydrates such as starch to simpler carbs, carbon dioxide, and alcohol.
In the past few hundred years, the yeast culturing process in making breads has undergone empirical analysis and is now an artisanal and industrial keystone to proper bread production. Previously, many cultures often (and to this day do) ate unleavened bread, or did not have concrete fermentation practices Many factors affecting bread qualities are considered by bakers, including the exact strain of yeast, its form, the types of flour, the ratios of these ingredients, additives and symbiotes, and leavening time. Additionally, contemporary biotechnology approaches such as genetic engineering have recently been employed in attempts to identify, select for, or transfer genes responsible for desirable phenotypes, such as increased (more or faster) fermentation, or the biosynthesis of certain secondary metabolites.
Biology of Yeast
Metabolic Pathways of Importance
Overall paper length should be 3,000 words, with at least 3 figures with data.
Preparation of Culture for Baking
Activation of Yeast Culture
Preparation of Dough
Discovering Sourdough, by Teresa Greenway—An excellent, comprehensive manual for cooking doughs, covering a range of baking considerations.
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Edited by Owen Z. Foster, a student of Nora Sullivan in BIOL168L (Microbiology) in The Keck Science Department of the Claremont Colleges Spring 2015.