14: quick bread / yeast bread Flashcards
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yeast = living, unicellular org from fungi
available options today vs before
dormant by…
today, we have 1868 Fleischmann yeast & Baker’s yeast
before. equal ratio of yeast: H20 / made from portion of dough / wild yeast
…drying or low temp storage
=> active again put in dough
how does yeast work? how does it digest starch?
ethanol evap during baking / acetic & succinic / starch
yeast anaerobically metab fermentable sugars: glu/su/fructose => ethanol & CO2
ethanol evap during baking -> impact vol
acetic & succinic acid impact gas holding capacity
has maltase + sucrase, convert starch -> maltose + sucrose
why add sugar to yeast?
speed up gas production: if over 10% -> slow fermentation -> BAD on vol
dmg starch -> maltose by a- & B-amylase
=> sugar for yeast
how is commercial yeast made?
test tube / wort
healthy yeast selected from deisred strains
transfer to test tube w/ nutrition to bud
transfer to growing medium called wort w/ carbs _ vit/min
afgter multiplied, ok for fermentation -> remove from wort
compare active dry yeast vs instant quick rising active yeast (1 gd thing, bad thing)
1: = living dormant yeast
rehydrate separately before added to dry ingre (NOT DIRECTLY)
loss of biodiversity is affected by air, moisture
- opp (add to dry ingre)
50% reduction in dough rising time
volatile in air -> pockaged in inert gas or vacuum
inactive dry yeast / nutritional yeast
inactivateb by pasteurisation duyring drying
used as dough conditioner not leavening agent
brks disulfide bond (gluten reducing agent) -> more extensible dough, retains CO2
whci yeast: mix of yeast H20 oil ) emulsifier
compressed yeast
=> short shelf life of 10 days chilled due ot mostly made of H20
soften in H20
=> most consistent quality, used by commerical baking
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bread machine yeast is ssimilar to ____
instant QUICK RISING active yeast bt w/ added ascorbic acid (a dough conditioner)
which flour to choose?
pentosans
choose bread flour, highest quality gluten protein
high protein -> high ydration capacity -> need that h20 for open txgure
fermnation weakens gluten -> stronger flour
pentosans (gum in flour_) makes it absorb more H20 -> good for VOL
salt firmen the gluten strucvutre
retards yeast femerntation -> longer dough rising time
liquid: dissolve suagar + salt
to activ yeast, water must be 40-46C
for lean + crisp dough
if excess, less gluten yielding -> bad for vol
if too lil, stiff, ineslastic,dry -> less glouten dvlopment
salt
sugarL sources? excess/lil?
sugar nat in flour, E hydrolysing the starch, added
< fermentation time
excess, rise quicker ; too lil, delay the action of yeast
fat softens bread & < shelf life TOR F
T
- < gluten extensibiliyt: good for vol good for txt
oxidising agent such as ascorbic acid: how does it help w/ gluten dvlopment?
stripping H from sufylhydryl bond -> free S fro disulfide bond for gluten development
combine w/ reducing agent for optimal gluten dvlopment
when mixing, air is incorp
do a test:
-> creates small gas nuclei
allows gluten + gliadin to come tgt randomly
yeast produces CO2 -> which increases the nuclei’s size bt not create new one
do a windowpane test: stretch to thin film
2ned step
when kneading gluten & gliadin adheres tgt. T or F.
F.
glutenin + gliadin -> creating a low elastic strand of gluten=> S S bond forms
starch traps into this
3RD STEP :
what happes in first rise, dough is ripeened?
organic acids & ama created
begins an aerobic rxn (20% O, 80% N) -> yeast consymes O2 entrapped in dough -> anaerobic rxn (only N remains)
…contributes to flavour:
pH 6-> 5: promotes fermentation, amylase activity
4TH STEP: punch down _ shape dough
gently handle, gently shape
- subdivide the air cell, redistribute the yeast cells + food substrate -> equalise temp
gently handle to keep the gluten network on air cells
- scaling [ divide dough into portions. -> gently shape & remove the large bubbles
what is the last step before baking?
30-35 C & 85% humidity
proof = final rise of dough -> dough doubles in size
if underproof, small & dense after baking
if over proof, collapse in oven
if high in protein, can sustain 2 rises =. higher loaf vol
types of breads & doughs
- high fibre = which is bad for gluten -> cuts gluten strAND -> LOW VOL DENSE BREAD
presoaking + finely grinding brand + adding shortening helps
vital wheat gluten + dough conditioner (rmb: oxidising agent)
bagel = proof shape boil bake
why boil? expands due to gas production & sets outer crust
to reverse staling & prioperly store
to reverse, toast @ 50-60C; can be done repeatedly til too much mositure loss
chilling promotes staling; freezing reverses it
narrate staling: crumb toughens -> firmems -> loses
toughens: h20 migrates from crumb to toast
firmens: amylosepectin retrogradation = monoglycerides form a complex w/ starch -> > retrograd & softens the crumb
looses moisture flavour crumb opaqueness
when spoilage? what is meant when stated “inside of dough will become ropey”?
2 types of bacteria
contam w/ mold spores, esp w/ moisture and hot weather
Ca proprionate added as anti-molding additive, bt it’s not all powerful
rope = a type of bacteri ain which spores remain alive during baking
inside of bread is ropey & have an overripe melon taste
to fix: acidfy dough to 4.5 w/ vinegar or buttermilk
BAKING- FILL IN THE BLANK
when it first goes into the oven,
overly hot oven __ bread ___ -> less __
steam ___ e.g think baguette
as dough’s temp <.
gluten < starch in what?
___ enchnces crust ___
=> 2 rxn
oven spring = sharp rise of dough from gas production; internal temp is 60C
sets bread before optimal oven spring -> vol
steam injection soften the crust & expands -> thin hard crust
yeast is kill, inacrtivate E, fermentation is stopped
in H20
malt enhances crust color
both maillard rxn & caramelisation occurs
