Lecture 18 Flashcards
What is the purpose of yeast?
Leaven baked dough products
What are the essential ingredients in yeast breads?
Flour
Liquid
Yeast
Salt
What kind of food system are yeast products?
Foam food system
Gases dispersed in dough mix
What are examples of lean doughs?
French/italitan bread
Hard-Crust rolls
What is an example of rich doughs?
Brioche
What are examples of fish sweet doughs?
Croissant
Danish
Cinnamon Roll
What is a fried yeast dough?
Doughnut
What is the texture like with yeast breads?
White bread has fine crumb, thin cell wall, uniform grain
Shape of cells vary
Crumb is elastic, and springs back when touched
What kind of breads tend to be more dense and why?
Breads made with 50% whole wheat flour are more dense
What is the appearance of yeast breads?
White bread looks golden brown crust
Well shipped load as rounded top, side it smooth and even
What factors affect the shape and volume of dough?
Stiffness of dough Strength of dough Fermentation Proofing Baking Temp Position in oven
What is the flavour of yeast breads like?
Yeasty
Other flavours are dependent on the type of bread
Sometimes sour taste due to time of fermentation
What is yeast?
Living unicellular organism
-a fungi
Can have many strains
What is the scientific name for bakers yeast?
Saccharomyces cerecisiae
Is yeast live when purchased?
Can be made formant after growth by drying or low temp
-can become active again once it is mixed into dough
What did people use before bakers yeast?
natural wild yeast
-equalt was flour and water was used to trap bacteria from the air and that’s what they use as the culture
Can yeast grow with or without O2?
Can to both
-begining stage is aerobic, later stage of baking is anaerobic
How does yeast work with bread?
Metabolizes fermentable sugars and ferments then anaerobically
-produces ethanol and CO2
What sugars can yeast readily metabolize?
Glucose
Fructose
Sucrose
Maltose
What happens to the alcohol (ethanol) when baked?
Evaporated and contributes to volume
What roles do acetic and succinct acids have on baking?
The acids impact gas holding capacity
CO2 trapped in flour gluten network
What does damaged starch turn into?
Hydrolyzed to maltose by alpha and beta amylase
What does yeast convert maltase and sucrase into?
The conversion hydrolyzes starch into maltose and sucrose
Why is sugar added to dough?
Speed up gas production
-but if its more than 10% sugar by wt then it will have a negative effect on yeast bread and can delay fermentation