Bread and pastry-Class 8 Flashcards
Key ingredients in bread making
Yeast Flour Water Salt Optional ingredients: shortening/fat, milk –or other liquid, sugar and eggs
Three categories of leaveners with examples
Chemical Baking soda, baking powder Mechanical / physical Air (egg whites, creaming sugar + butter…) Steam (liquid, eggs) Biological Yeast Bacteria
What do yeast produce and what does it do
Produces zymase, an enzyme that ferments sugar:
Glucose →ethanol + CO2+ other by-products
Basic functions of yeast
CO2 leavens the dough
Variety of by-products contribute to bread flavour
Fermentation process develops the dough
What is the name for yeasts used in baking
Saccharomyces Cerevisiae
Why Saccharomyces Cerevisiae are used in baking
Good CO2 production
Development of desirable flavour
Adequate keeping qualities
Three types of yeast
- compressed
- Active dry yeast
- Instant yeast
What are compressed yeast and do you need to do with them
Fresh
Requires refrigeration unless it is frozen (very perishable)
What are active dry yeast, what should be dine with them
Dehydrated
Rehydrated in water at 43-46°C
Why active dry yeast should be rehydrated at particular temperature
Higher temp = inactivated
Lower temp = leaching of cell contents into liquid, which softens bread dough
How instant yeast are used
Added directly to dry ingredients
Optimal temperature of dough for yeast activity
30-35C
What are other optimal conditions for yeast activity
Hydration activates dormant yeast High osmotic pressure (too much sugar/salt) inhibits activity pH slightly acidic (4-6) is optimal Must have enough food (sugar)
What are the substrates for yeast activity and where you can find it
Substrate (sucrose, starch)
Added to the dough (sucrose)
Naturally in flour (1-2% sucrose; starch)
types of enzymes that are in yeast and flour and how they work
- Flour amylases
α-amylase catalyzes: starch → random smaller pieces
β-amylase catalyzes: starch → maltose
2. Yeast
Maltase catalyzes: maltose → glucose + glucose
Invertasecatalyzes: sucrose → glucose + fructose
Yeast fermentation with oxygen and without oxygen
With oxygen: glucose->CO2+water
Without:glucose->ethanol ->CO2
What amounts of sugar are usually added to bread with respect to flour
Small amount added (< 8% of weight of flour):
Provides a readily available substrate for immediate gas production by yeast
Larger amounts of sugar that are added to bread making
Inhibits yeast activity
Tenderizes by interfering with gluten development
Browning due to Maillard reaction
Wheat flour provides ___ to the bread
the proteins (glutenin& gliadin) from which gluten is developed during hydration and mixing
WHat is flour
Fine powder derived from endosperm of seeds or from other starchy foods
Wheat is the most common type of grain for bread, what other types can be used
oat, rye, barley, rice, corn, triticale (wheat/rye hybrid)
Some non-cereal sources: soy, chickpea, potato, cattail, taro, arrowroot, coconut
Flour is a base for what bakes products
Basis for all baked products
Yeast breads
Quick breads
Whole wheat flour includes in itself
(bran, germ, endosperm)
White flour includes in itself
endosperm only
In what way gluten flour is made
(milled in a way to retain gluten)
All-purpose flour has gluten potential that can be compared to
in between cake & bread)
Durum flour is made from
Semolina
What flour -bread or pastry/cake- has more gluten
Bread flour (high gluten) Pastry & Cake(lower protein)
What are insoluble proteins in wheat
•Gliadin and Glutenin
Soluble flour proteins and where they are dissolved
Soluble flourproteins (in dilute salt solutions) •Albumins •Globulins •Glycoproteins •Nucleoproteins •Lipid-protein complexes •Enzymes: amylases and proteases
What determines flour properties during baking
Quantity and quality of proteins in flour
What percentage of flour is gliadin/glutenin and non-gluten forming proteins in wheat flour
gliadin/glutenin->85%(dough forming)
non-gluten forming ->15%
Properties of gliadin
Hydrophilic, single spherical polypeptide chains
Fold onto themselves, bonding weakly with each other
Fluid and sticky
Properties of glutenin
Hydrophobic, longer than gliadin
Largest component of gluten complex
Bond more strongly with each other
Form strong S-S bonds at the end of the chains
Contributes to elastic properties of flourdough
Gluten control what properties in dough
the rheological (flow): plasticity and elasticity
What gluten is forming and what is embedded in it
Gluten forms a continuous, 3-dimensional network of hydrated proteins in which starch granules are embedded
What does hydration do to gluten fromation
- Distributes air bubbles
- Gliadinand Gluteninabsorb 2x their weight in water and become gluten
- Other proteins (albumin and globulin) become main part of dough
- Result –a complex of gluten with water in the spaces
What does kneading do to gluten formation
- Used extensively inbread making
- Working dough intoelasticmass by pushing, stretching, folding.
- Expands gluten strands
- Distributes yeast
- Warms dough; increases fermentation
- Helps distribution of CO2
Gluten proteins are cross-linked by
S-S bridges
Flatter sheets of gluten results in
Smoother, finer texture
What dies fat and sugar do with gluten
Fats->coating, prevents clumping
Sugar binds water->prevents gluten formation
What is happening when flour is mixed with water
Glutenin proten molecules link up end-to end to form long, composite gluten molecules.
Why dough is elastic
Dough is elastic because the gluten molecules are coiled and have many kinks in them. When a mass of dough is stretched , the kinks are straightened out, the coils extended, and the proteins get longer. When the stretching tension is released, many of the kinks and coils re-form, the protein mass shortens, and the dough shrinks back toward original shape
Why do you need to knead under cold water
water-soluble proteins & starch freed
gluten remains
The definition of gluten
general name given to the storage proteins (prolamins/peptide fractions) present in wheat, rye and barley
What proteins are toxic to people with celiac disease
gliadin in wheat
secalin in rye
hordein in barley
(avenin in oats)?
What is celiac disease: symptoms, how you can get it, in general what is it
Immune system reaction to gluten
Affects GI tract –malabsorption
Genetic transmission
Estimated prevalence in Canada 1:133
Symptoms: abdominal bloating, diarrhea, fatigue, weight loss…
Non -gluten grains
millet,teffand rice + non-contaminated oats
Gluten substitutes
Xanthan gum Guar gum Psyllium seed husk Chia seeds Flax seed meal Gelatin Agar agar
What is the role of starch in flour when baking
Strengthens through gelatinization Dextrins contribute to colour& sweetness Contributes to crumb Texture of baked product’s interior FINE = small, densely packed air cells COARSE = large, irregular holes
Why liquid is necessary for baking
Liquid in bread is necessary to hydrate proteins and starch and for gluten development
What is the most common liquid used for baking and why
Milk
Adds nutrients
Gives a finer texture
Improves crust and crumb color and flavor
Whey softens the dough and decr volume, therefore milk must be heated before using to denature whey pro
How much salt is added to the recipe
(< 2% of weight of flour)
What does salt adds to baking
Improves taste of bread
Stabilizes yeast fermentation (slows its activity)
Changes rheological properties of the dough
Has a firming effect on gluten
Increases water holding capacity of dough
Cl ions help gluten proteins stick together
How does the dough with no salt and double salt looks like
no salt-> double size the normal salt
Double salt-> more compact and smaller than normal salt
How much fat is added to bread recipe
(< 3% of weight of flour)
Functions of fat in bread making
Increases loaf volume
Gives a more uniform and tender crumb
Improves slicing properties (less crumbly)
Enhances keeping quality (decreases staling)
Eggs are ___ in bread-making
optional
What salts can be added to dough and why
Calcium and ammonium salts
Supply nutrient need of yeast cells
Provide a slight buffering action
Ca has a firming effect on gluten
What oxidizing agents can be added to the dough and why
(K & Ca bromates and iodates)
Set the structure of the protein network in the dough
What dough conditioners can be added to the dough and why
(polyethylene monostearate& polysorbate 60)
Strengthen the gluten structure and improve its gas-retaining ability
What are dough softeners and why they are added
Dough softeners (monoglycerides, sodium stearyl-2 lactate) Increase shelf life of bread by retarding firming of crust
What enzymes can be added to the dough
(e.g. proteases)
Improve dough handling and extensibility
What antimolding agents can be added to the dough and why
Antimoldingagents (sodium and calcium propionate)
Inhibit growth of spore forming organisms
What fibers and antioxidants can be added to dough
Fibers(from cellulose or bran)
Antioxidants(BHA, BHT)
IngredientsItalian Crusty Bread 100% Whole Wheat
I know it is stupid , but she might ask to recognize
Whole wheat flour, sugar or glucose or fructose, vegetable oil, wheat gluten, yeast, salt, corn syrup, barley, malt extract, vinegar, sodium stearoyl-2-lactylate, diacetyltartaric acid esters of mono and diglycerides, calcium propionate, calcium sulphate, calcium iodate
Toppings: potato starch
What are steps in breadmaking
During mixing & kneading: numerous cells of air are incorporated and development of the gluten structure in dough
During fermentation/rising: decrease in pH (production of CO2 and lactic acid)
After fermentation: gas vacuoles are formed in the mixture
After dough has risen: punched down to permit a uniform distribution of gas cells throughout the dough
After punching down: proofing allows dough to rise in the pan after fermentation and before baking
What happens during kneadling
Unfolds and aligns the long initially tangled gluten molecules cross linked by sulfide bonds
What will happen to the dough as yeast are fermenting
As the yeast ferments, the dough will double in size as carbon dioxide
is produced by the yeast and as enzyme and pH changes take effect.
What does over -proofing do to the bread
Produces a low volume bread due to collapsing cells and the escape of
fermentation gases
The purpose of punching down bread
Allows excess gas to escape and redistributes the ingredients
What happens during baking with bread
Within the first few minutes
Yeast activity stimulated -CO2(until inactivated at ~60°C )
Volume increases markedly =oven spring
Adequate volume is dependent upon the ability of the gluten mass to:
Expand
Produce thin cell walls that hold gas up to the point of setting the structure
Brown color of crust is due to
Maillard reaction
Caramelization of sugar
What happens in general during baking in bread
Changes appearance, texture, flavour, aroma Yeast killed Protein coagulates Starch swells & gelatinizes Fat melts Crumb development
What is oven spring
The quick expansion of dough during the first ten minutes of baking, caused by expanding gases.
What happens after baking with bread
Much of the starch is gelatinized
Gas vacuoles are dispersed throughout the structure
Characteristic flavor of freshly baked bread related to
volatile and nonvolatile substances produced during fermentation (alcohols, organic acids, esters & various carbonyl compounds)
When do Characteristic flavor of freshly baked bread begins to change
Begins to change within a matter of hours after baking (staling begins!)
What is staling and what does it involve
Involves mainly the amylopectin fraction of starch which undergoes retrogradation(crystallization)
Causes
Change in taste and aroma
Increased hardness, opacity and crumbliness of crumb
The difference between fresh baked, fresh bread and stale bread
Fresh baked- Immediately out of the oven, both amylose (straight chains) and amylopectin (branched structures) are swollen and randomly oriented
Fresh bread- during cooling (1hr), the amylose molecules begin to align and crystalize
Stale bread- during staling (several days), amylopectin realigns and reforms crystallites
The simplest yeast bread is made from:
Flour
Water
Yeast
Varieties of yeast bread that include loaf breads:
White
Whole-wheat
Sourdough
Malt bread
Other varieties of bread
Rolls Pita Bread Bagels English Muffins Pizza Crust Raised Doughnuts Specialty Breads
Two types of pastry
Nonlaminated
Laminated
Nonlaminated type of pastry
Plain pastry or pie pastry used for:
Pie crust, tarts, tartlets, galettes
Brioche pastry
Choux pastry
Laminated type of psarty
Puff pastry (e.g.quick pastry, phyllopastry, croissant pastry, danishpastry
Characteristics of pastry
Relative high fat content: sweet rolls, puff pastry
Both flakiness and tenderness are desirable characteristics of pastry
Flakiness depends on
depends on an imperfect blend of fat and flour (degree of separation)
Who is the major contributor to flakiness in pastry and how it is measured
Fat is the major contributors to flakiness of pastry by:
Size of its particles
Its firmness
How evenly spread
Flakiness is measured by the size of the flakes (long flake, short flake or no flake/mealy crust)
The role of fat in producing flaky pastry
From down to top
Dough(hydrophyllic)
Layering of fat(hydrophobic)
Steam (вжух-вжухч in between two layers of fat)
added by kristina:
• Water in the dough turns to steam upon baking
• The layering fat creates an impervious layer
• The steam stays inside each dough layer, forcing it to expand because of the pressure it develops underneath each impervious fat layer
Tenderness is maximized when
fat coats flour, preventing hydration of flour particles -therefore inhibiting gluten formation
Shortening power of fat is related to
degree of unsaturation
more unsaturation = more tender pastries
oil> lard and shortening
The effect on the way of adding fat to pastry
Tender pastry occurs
when fat melts more into flour
Flaky pastry is achieved
with cold fat in pea-size
balls
Tenderness is increasing with ___
increasing amounts of fat
General instructions for fat in pastry
In general, from ¼ to 1/3 cup of fat is used for each cup of flour in making pastry of acceptable tenderness
Tenderness of piecrust relate to
protein content of flour
What develop gluten strands that toughen the pastry (decrtenderness)
Too little shortening Too much flour used during rolling Increasing protein content (egbread flour) Over-manipulation of dough Increasing liquid Water Salt
What is a classical method of mixing pastry
- Flour and salt sifted together
- Cold fat cut into the mixture (using a pastry blender or a fork)
- Cold water sprinkled one tablespoon at a time over the flour
- When dough well mixed, wrapped and refrigerated (to chill the fat)
The fat should be cut to ( according to her slides)
the size of tiny peas
How mixing of puff pastry occur
2 separate mixtures
Fat component or butter block (fat, flour, salt and an acid)
Dough (flour, salt, water and a little fat)
Both will be refrigerated and then folded and rolled together
Insufficinet and excessive folding results in
Insufficient->more volume than desired
Excessive-> compact
What are surface agents added to the dough?
Dough conditioners
Dough softeners
