bread and pastry Flashcards
1
Q
what are the main ingredients in yeast breads?
A
yeast
flour
water
salt
2
Q
what are some optional ingredients in yeast bread?
A
shortening/fat
milk
sugar
eggs
3
Q
what are the 3 leavening categories?
A
- chemical
- mechanical/physical
- biological
4
Q
what type of leavening agents is baking soda and baking powder?
A
its a chemical leavening agent
5
Q
what incorporates air as a leavening agent?
A
egg whites
creaming suagr & butter together.
6
Q
what type of leavening agent do steam and air function as?
A
mechanical/physical
7
Q
sourdough makes use of what as a leavening agent?
A
yeast & bacteria
8
Q
what does yeast produce? and what does it provoke?
A
zymase
it ferments sugar
glucose –> ethanol + co2
9
Q
what is the function of co2 in yeast breads
A
leavens the dough
10
Q
what does the fermentation process do?
A
it develops the dough
11
Q
what is saccharomyces cerevisie?
A
it is the yeast used by bakers to make bread
-good co2 production
develops desirable flavor
good for keeping qualities
12
Q
what are the 3 types of yeast?
A
compressed
active dry
instant yeast
13
Q
how does instant yeast function?
A
added directly to dry ingredients
14
Q
how does active dry yeast function?
A
it is dehydrated
and rehydrated in water at 43-46 C
15
Q
what happens to active dry yeast when added to water at higher temperatures?
A
it gets inactivated
16
Q
what happens to active dry yeast when added to water at lower temperatures?
A
leaching of the cell components into the liquids which will cause for the bread dough to be softened
17
Q
what is compressed yeast?
A
it is fresh
requires refrigeration of freezing as it is very perishable
18
Q
what is the optimal temperature for yeast fermentation?
A
30-35C
19
Q
what does hydration do to dormant yeast?
A
it activates it
20
Q
what will too much salt or sugar do to the yeast?
A
it will activate it.
a result of high osmotic pressure
21
Q
what pH is optimal for yeast?
A
slightly acidic
ph between 4-6
22
Q
what must yeast have in sufficent amounts in order to survive and feed?
A
sugar (glucose)
23
Q
how much sucrose and starch is naturally found in flour?
A
1-2% sucrose
starch
24
Q
what does a-amylase catalyzes?
A
starch —> random smaller pieces
25
what does B-amylase catalyzes?
starch --> maltose
26
what does Maltase catalyzes?
maltose --> glucose + glucose
27
what does invertase catalyzes?
sucrose --> glucose & fructose
28
what are malatase and invertase enzymes?
yeast enzymes
29
why do yeast need glucose?
in order to produce fermentation and yield co2.
30
why is sugar added to yeast breads?
it provides a readily available substrate for immediate gas production by yeast
31
what amount of sugars should be added to yeast breads?
< 8% of weight flour
32
what happens if large amounts of sugar are added to yeast breads?
- inhibits yeast activity
- tenderizes the bread and interferes with gluten development
- causes browning due to maillard reaction
33
what does flour provide in bread making?
the proteins glutenin and gliadin from which gluten is developed during hydration & mixing.
34
why are liquids added to breads?
in order to hydrate proteins and starch for the development of gluten
35
why is milk the most common liquid added to bread?
- adds nutrients
- gives a finer texture
- improves crust and crumb color and flavour
- whey will soften the dough and decreased the volume.
36
why must milk be heated before adding it to the bread?
in order to denature the whey proteins.
37
how much salt should be added to bread?
<2% of flour weight
38
why is salt added to bread?
- improves taste
-stabilizes yeast formation
- changes properties of the bread
-has a firming effect on gluten
increases water holding capacity
increases mixing needs
39
if we decide to add fat and eggs to bread how much should be added?
< 3% of flour weight
40
why would eggs and fat be added to breads?
improves the loaf volume
gives a uniform and tender crumb (less crumbly)
decreases staling
41
why are calcium and ammonium salts added to doughs?
supply nutrients needed for yeast cells
act as buffers
calcium has a firming effect on gluten
42
why are potassium/ calcium bromates & iodates added to doughs?
they act as oxidizing agents and set the structure of the protein network in doughs
43
what are the 2 types of surface active agents?
- dough conditioners
| - dough softeners
44
give an example of a dough conditioner and how it functions.
- polyethylene monostearate & polysorbate 60
| - strengthens the gluten structure and improves its gas-retaining ability
45
give an example of a dough softener and how it functions.
- monoglycerides, sodium stearyl-2 lactate
| - increases shelf life of bread by retarding firming of the crust
46
how do enzymes like proteases act on doughs?
they improve dough handling and extensibility
47
how do anti-molding agents like sodium/calcium propionate act on doughs?
they inhibit the growth of spore forming organisms
48
what are examples of fibers that may be added to doughs?
cellulose
| bran
49
what type of antioxidants may be added to doughs?
BHT
| BHA
50
what is the function of sodium stearoyl-2-lactylate?
improves ability to hold CO2 and makes dough soften and more lengthened
51
what is the function of diacetyl tartaric acid esters of mono and diglycerides?
they serve as emulsifiers and ensure that everything is well mixed
52
why is potato starch added to breads?
it gives breads a glossy topping texture
53
what is incorporated during mixing and kneading and what does it result in?
numerous air cells are incorporated
| gluten structure is developed in the dough
54
what happens to the pH during fermentation and rising?
it decreases due to the production of co2 and lactic acid.
55
when are gas vacuoles formed in the mixture?
after fermentation
56
what must be done to the dough after it has risen? what does this permit?
it needs to be punched down to allow a uniform distribution of gas cells throughout the dough.
57
after the dough had been punched down what should be done?
proofing as it will allow the dough to rise in a pan before it gets baked.
58
why should the dough be kneaded?
it unfolds and aligns the ling initially tangled gluten molecules which are cross linked by sulphide bonds and results in sheets of gluten yielding a smooth texture
59
what is the best method to knead dough
forward- down and away motion.
60
where should dough be place to allow rising?
it should be place in a undisturbed, humid and warm place.
61
what does over proofing bread cause?
it produces a low volume bread because the cells collapse and allow fermented gas to escape.
62
what happens during the first few minutes of baking?
yeast activity is stimulated
gets inactivated at around 60C
volume increases = oven spring
63
what is volume dependent upon
the gluten mass
allows it to expand
produce a thin cell wall that holds gas to the point of setting structure
64
when does the browning of the crust happen and why?
during cooking due to maillard reaction & sugar caramelization
65
what happens during baking?
- changes in appearence, texture, flavour and aroma
- yeast is killed
- proteins coagulate
- starch swells and gelatinizes
- fat melts
- crumb develops
66
what is oven spring
it is the quick expansion during the first 10 minutes of baking.
results from expanding gas molecules.
67
what is the result after baking
much of the starch is gelatinized
| gas vacuoles are dispersed throughout the entire structure.
68
what is bread flavour relative to?
volatile & nonvolatile substances produced during fermentation
69
when does staling begins?
only hours after baking is done.
70
what is staling?
it involves amylopectin fraction of starch which undergoes retrogradation (crystallization)
71
what does stalling cause?
changes in taste and aroma
| increases the harness, opacity and crumbliness of the bread.
72
what are the 2 types of pastries?
1. laminated
| 2. nonlaminated
73
what are the examples of non laminated pastries?
-plain pastry crust or pie pastry
brioche pastry
choux pastry
74
what are the examples of non laminated pastries?
- puff pastry
- croissant
- danish pastry
75
what is flakiness? and what does it depend on?
- Flakiness is measured by the size of the flakes (long flake, short flake or no flake/mealy crust)
- depends on an imperfect blend of fat and flour (degree of separation)
76
what are major contributors in pastry flakiness?
- size of its particles
- firmness
- how evenly spread
77
large flakes result in what?
the flakiest type of pastry
78
what is mealy referred to in terms of pastry?
it is the least flaky and had barely any flake.
79
what is the role of fat in producing a flaky pastry?
layering fat is hydrophobic and steam gets trapped between 2 fat layer covering the dough
80
what is tenderness maximized by?
Maximized when fat coats flour, preventing hydration of flour particles - therefore inhibiting gluten formation
81
what is the shortening power of fat maximized by?
-the degree of unsaturation
hence more saturated = more tender pastries.
hence oil > lard and shortening
82
what type of pastry is yielded when fat melts into flour?
a tender pastry
83
what pastry is obtained when cold fat of pea-size shape is obtained?
a flaky pastry
84
what increases as fat increases?
tenderness
85
what is the general amount of fat/flour used for appropriate tenderness
1/4-1/3 cup of fat per cup of flour
86
what is the tenderness of pie crust related to?
the protein content of flour. more gluten formation means a thougher dough.
87
what other factors may yield a less tender dough
- too little shortening
- too much flour used to roll out the doughh
- using bread flour increases protein content
- over manipulation of the dough
- increasing liquid content
88
what are the 4 steps in classic pastry method?
1. flour and salt are stiffed together
2. cold fat cut into the mixture (using a pastry blender or a fork)
3. cold water is sprinkled one table spoon at a time over the flour
4. when dough is well mixed, wrap it and chill it.
89
how to make puff pastries
make 2 separate mixtures 1. fat components, (fat, flour, salt and an acid)
2. dough (flour, salt, water and a bit of fat)
both are refrigerated and the folded and rolled together
90
what happens if a puff pastry is over folded?
big air vacuoles form
91
what happens if puff pastry is excessively folded?
very small air vacuoles form and dough collapses.
