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leavening equals what ?
Rise or increase in volume
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What is gluten?
a structural protein that is essential to breads
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what two proteins is it primarily form the gluten complex?
- Gliaden (fluid)
- and
- Glutenin ( elastic)
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Gluten complex develops when flour is ?
- Moistened (hydrated)
- and/or
- manipulated (kneaded/mixing)
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Hydration (moist ingredients) does what?
Pulls the two proteins (Glutenin and Gliaden) in flour from endosperm cells
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Kneading/mixing does what ?
- –Realigns proteins to form crosslinks (like rubberbands) to give strength.
- –In yeast breads, warms the dough and increases fermentation and CO2 gas production
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Steam, air, and CO2 (biological, chemical) do what ?
Leaven bread
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Leavening Agents
what are the two physical leavening agents?
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describe what 4 processes create air in products
- Creaming fat and sugar
- Beating egg whites
- Sifting flour and dry ingredients
- Kneading
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explain three details of steam:
- –H2O increases 1,6000X in volume as it vaporizes and expands
- –Leavening in all batters and doughs
- –Only leavening agent in popovers and creampuffs
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What type(s) of leavining agent(s) is CO2 ?
plus explain
- –---Chemical
- baking soda/powder yield CO2 when mixed with an acid in the presence of liquid.
- –---Biological
- yeast
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Biological
•what is the biological leavening agent?
Yeast - sacchromyces cervisiae
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–Yeast use sugar and produces what ?
CO2 and H2O
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•Flour has what percent sugar?
1.5% sugar
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•What can yeast hydrolyze?
starch
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–Yeast multiplies at what degrees?
68° - 81°F
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–Yeast ferments at what degrees?
81° - 100°F
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–Yeast will die if the temp exceeds ? what else will kill yeast?
- 135° - 140°F
- •Salt also kills yeast
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3 enzymes that are produced by yeast:
- –Diastase
- –Invertase
- –Zymase
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–Diastase does what?
•Converts starch to maltose (which is a disaccharide)
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–Invertase does what?
•Converts disaccharides to monosaccharides
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–Zymase does what ?
•Converts monosaccharides to CO2 and alcohol
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what are the 3 Types of Yeast for Breads
- •Dry Active yeast
- •Fresh Yeast (compressed)
- •Instant
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• 5 Dry Active yeast details
- –Dehydrated form of fresh yeast (fermented form)
- –Most common type, can be stored at room temp
- –It is reactivated by heating 110°-115°F for 3-5 min.
- –Temp below 100F lowers activity
- –Temp above 140F kills yeast
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•Fresh Yeast (compressed) details
- –70% moisture (70% more yeast), refrigeration required due to moisture
- more commercially used
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•Instant details
- –Not completely dehydrated
- –Used commercially
- –Reproduce more quickly, dough rises 2X as fast
- –Less flavor
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Chemical Leavening:
what are the two chemical leavining agents?
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•For baking soda (NaHCO3) to produce CO2 what must be added
- ACID MUST BE ADDED
- –Baking soda alone will leaven but creates sodium carbonate (Na2CO3) which tastes bad/bitter
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•Baking soda + heat =
sodium carbonate + H2O + CO2
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Baking soda + acid =
salt + carbonic acid = H2O + CO2
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When baking soda is combined with an acid it must be baked immediately
–This is because the reaction produces H20 (too much water means tough because too much gluten development)
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7 Food acids to use with baking soda:
- –Cream of tartar
- –Lactic acid– buttermilk or yogurt
- –Aconitic acid– molasses, brown sugar
- –Acetic acid – vinegar
- –Citric acid– lemon/orange juices
- –Gluconic acid– honey
- –Malic acid– apples and pears
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The type of acid determines what ...
the speed of CO2 produced
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how is baking powder different than baking soda?
it is baking soda with the acid already added plus inert filler (cornstarch)
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What are the two types of baking powder?
+how many acids does each contain?
- fast, single acting (contains 1 acid)
- slow, double acting (contains 2 acids = reacts twice)
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3 details of the fast single acting?
- commericail use only
- contains tartaric acid or monocalcium phosphate
- bake immediately, reacts quikly
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4 details of the slow double acting?
--what are its contents?
--what does wet base+monocalcium phosphate= ?
--what does heat applied to SAS produce?
--what does lefteover base+sulfuric acid = ?
- --base+monocalcium phosphate(acid)+sodium aluminum sulfate(SAS)
- -- CO2 formed; some base left
- --sulfuric acid
- --CO2
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What is the recipe for homemade baking powder?
- 1/2 tsp cream of tartar
- 1/4 tsp baking soda
- 1/4 tsp cornstarch
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What are the three Types of Bread ?
- •Yeast Breads
- •Quick Breads
- •Cakes/Cookies
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• what are Yeast Breads plus examples ?
- –Fermented after mixing ingredients
- –Examples: bread, rolls, raised doughnuts
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•what are Quick Breads plus examples ?
- –Leavened by air, steam, chemical agents (baking soda/powder)
- –Examples: muffins, biscuits, popovers/cream puffs, tortillas
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• what are Cakes/Cookies plus examples?
- –Leavened by chemical agents
- –Usually significant amount of fat added compared to other types of bread
- –Examples: cake doughnuts, all cakes & cookies
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Quick Breads
– why are they Named ‘quick’ ?
- because they are cooked quickly after mixing
- •This is because these breads are leavened during baking with air, steam, and CO2 produced from the baking soda/powder.
- •There is no need to wait for slow fermentation and leavening to take place like in yeast breads.
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–2 important considerations for quick breads:
- •Consistency of batter
- •Temperature
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–2 types of quick breads ?
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Quick Breads– Batters & Doughs
•Batters:
– what is the Goal with batters
to avoid gluten over-development, so they are only mixed briefly
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what are the different methods for the two different types of batters:
- The pour method: pancakes, crepes, waffles, popovers, cream puffs
- The drop method: muffins, cornbread
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pour method details?
- –Liquid to flour ratio is about 1:1
- –Sometimes cooked at high temperature to produce steam, then low temperature to brown crust
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drop method details?
•–Liquid to flour ratio is about 1:2
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•Doughs: details
- –Contain more flour and are kneaded: tortillas, biscuits (High fat content prevents over-development of gluten)
- –Liquid to flour ratio is about 1:3
- –(Comparison: pastries have 1:6 ratio)
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Preparation & Comparison of Flatbreads
•What does yeast consume?
•What does yeast expel that causes leavening in bread?
•What compound kills yeast?
•What temperature kills yeast?
–Sugar (starch can be hydrolyzed into sugar by yeast)
–CO2 and H2O
–Salt
–Approximately 135-140 °F
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Preparation & Comparison of Flatbreads
•Tortillas are considered unleavened breads, but they are actually leavened slightly by what?
•What causes the bubbling on the surface of tortillas when they are cooked?
–Steam
–Steam (from moist ingredients and heat)
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Preparation & Comparison of Quick Breads
•Explain why popovers and cream puffs rise without any baking soda, baking powder, or yeast.
•What is the purpose of baking at 2 different temperatures?
•What type of quick breads are popovers and cream puffs? Is the pour or drop method used?
•What is the approximate ratio of fluid to flour in popovers and cream puffs?
–They are steam-leavened
–The first hotter temperature is needed to create steam; the second lower temperature is needed to brown the crust
–Batter; Pour method
–1:1
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Effect of Manipulation on the Quality of Biscuits
•What is the optimal number of strokes to knead a biscuit?
•Describe the effects of under-kneading.
•Describe the effects of over-kneading.
•What is the approximate ratio of fluid to flour in biscuits?
–Approximately 20 strokes
–Low volume/height
–Tough texture (because of gluten over-development), low volume/height (because of loss of CO2)
–1:3
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Effect of Manipulation on the Quality of Muffins
•What is the optimal number of strokes to use when mixing muffins?
•Which of the muffins was the tallest? Why?
•Is it easy to over-stir muffins? Why?
–Approximately 15 strokes
–45 strokes; because the over-developed gluten trapped the CO2, forming tunnels and big pockets of air
–Yes; because the batter appears as though it needs to be mixed further (visible small clumps of flour), but it shouldn’t be
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