Yeast and Fermentation
Something that causes dough or batter to rise by producing gas.
Define an enzyme.
A specialized protein that speeds up chemical reactions
What is gluten?
A protein network that gives dough its stretchy, chewy, and elastic structure.
What does it mean to emulsify ingredients?
To mix substances that normally cannot combine into a stable and even mixture.
What is the most commonly known fat used for baking?
Butter
Why does dough rise when yeast is added?
Yeast is a leavening agent; it carries out fermentation, which produces CO2 gas. The CO2 gas is trapped inside the dough, causing it to expand.
Why is amylase important in dough?
Amylase helps to initiate fermentation by breaking down starch into smaller sugars.
Two proteins are needed to make gluten. What are they?
Glutenin and gliadin.
Why are eggs vital in cake batter?
Eggs provide proteins that allow it to coagulate and emulsify; It can help with structure, stability, moisture retention, and texture.
What characteristic of butter makes it so different than other fats?
It has water
Why does yeast use fermentation instead of cellular respiration?
There is very little oxygen available inside dense dough. Cellular respiration requires oxygen, therefore yeast switches to fermentation because it is an anaerobic process.
Why does refrigerating dough slow down rising?
Cold temperatures decrease the activity of enzymes and yeast, and the fermentation reactions happen more slowly.
How is gluten important for trapping gas in bread dough?
Gluten forms a strong, flexible network that traps CO2 gas; The air pockets expand instead of escaping because of it.
Why is lecithin able to mix oil and water together?
It is a phospholipid, meaning it has a hydrophilic region and hydrophobic region. Because it is able to interact with both substances, it helps to evenly distribute oil and water in batter.
Describe the relationship between the strength of gluten and the denseness of a baked good.
Gluten strength increases, denseness increases
As yeast produces carbon dioxide gas, the gas gets trapped inside the gluten network of dough. These trapped gas bubbles expand over time, stretching the dough out.
What is the difference between amylase and protease?
Amylase breaks down starches into sugar for fermentation; Protease breaks down proteins in the dough to relax the gluten network.
Compare the roles of glutenin and gliadin.
Glutenin provides strength and elasticity; Gliadin contributes extensibility, allowing it to stretch without tearing.
What happens during coagulation?
Heat causes egg proteins to unfold and denature, and they are able to bond together easily to form a final structure.
Describe how butter is relevant in cookies.
In the oven, the water from the butter will evaporate, causing it to expand and puff up as it bakes.
A baker notices their dough doesn't not rise after several hours. What could've gone wrong?
The yeast died, or the temperature wasn't fit for fermentation.
A baker hears that increasing the temperature can increase enzyme activity. He preheats the oven to 150 degrees F so that his dough can ferment faster. Instead, his dough becomes sticky, weak, and collapses easily. What went wrong?
The enzyme activity may have sped up too much; The yeast fermented rapidly, causing overproofing, making the dough have a weak structure.
Also accept: The enzymes denatured from the heat, therefore did not ferment properly.
Kneading your dough can strengthen the gluten network. A baker kneads their dough for a long time because they want a more stable, chewy, elastic dough. Instead, their dough ends up tearing easily and can barely stretch. What went wrong?
The baker over mixed or over kneaded his dough. Over mixing can lead to an overdeveloped gluten structure, which is why the dough ended up so tough.
A baker swaps all the brown sugar in a chocolate chip cookie recipe for white sugar. After baking, the cookies become crispier, drier, and less chewy than usual. Explain why this happened.
Brown sugar has molasses, white sugar does not. Molasses is highly hygroscopic and retains a lot of moisture.
A baker wants softer cookies but accidentally uses less butter than the recipe calls for. Predict how the cookies will change and explain why.
The cookies will become harder and denser. Butter is fat, and fat helps to weaken gluten formation, so if there is less of it, the gluten network becomes stronger and the dough loses softness.