Yeast

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Ebrahim Abdulaziz
Design Lab Report

Research Question:
How is the rate of yeast fermentation of 7.5g of yeast affected by using different companies of yeast (Bakon Yeast Inc., Lake States Yeast LLC, Lesaffre Yeast Corp, Red Star Yeast Company, and Minn-Dak Yeast CO Inc.)?

Background Information:

Yeast is a fungal microorganism that is used to manufacture mainly bread and beer. It reproduces rapidly. Fermentation is the process by which yeast takes in sugar and releases alcohol and carbon dioxide. Fermentation requires a mostly a damp and wet environment to occur. Different yeasts respond differently to changes in environment, making some better for baking and others for brewing. Bakers use fermentation to add CO2 bubbles to bread dough. During baking, these bubbles make the bread light expands while the alcohol boils away. Brewers take care to preserve the alcohol of fermentation and use the CO2 to help build a frothy head for their potent beverages. Yeast Fermentation is controlled by some factors:

Temperature – Enzymes that work on the yeast and ferment it, work in a specific temperature. If the temperature of the yeast and its surrounding is low, then the enzymes will not act on the yeast and the yeast will not ferment. But when the temperature exceeds the temperature needed for the enzymes to be activated, it will denature the enzymes and the yeast will not ferment. Age - Individual cells of the yeast have a finite replicative lifespan, which is believed to be a function of the number of divisions undertaken. As a consequence of ageing, yeast cells undergo constant modifications in terms of physiology, morphology and gene expression. Such characteristics play an important role in the performance of yeast during alcoholic beverage production, influencing sugar uptake, alcohol and flavour production. However, although yeast fermentation performance is strongly influenced by the condition of the yeast culture employed, until recently cell age has...
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