14: quick bread / yeast bread

Question 1

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yeast = living, unicellular org from fungi
available options today vs before
dormant by…

Answer 1

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

Question 2

how does yeast work? how does it digest starch?

ethanol evap during baking / acetic & succinic / starch

Answer 2

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

Question 3

why add sugar to yeast?

Answer 3

speed up gas production: if over 10% -> slow fermentation -> BAD on vol
dmg starch -> maltose by a- & B-amylase
=> sugar for yeast

Question 4

how is commercial yeast made?

test tube / wort

Answer 4

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

Question 5

compare active dry yeast vs instant quick rising active yeast (1 gd thing, bad thing)

Answer 5

1: = living dormant yeast
rehydrate separately before added to dry ingre (NOT DIRECTLY)
loss of biodiversity is affected by air, moisture

2. opp (add to dry ingre)
   50% reduction in dough rising time
   volatile in air -> pockaged in inert gas or vacuum

Question 6

inactive dry yeast / nutritional yeast
inactivateb by pasteurisation duyring drying

Answer 6

used as dough conditioner not leavening agent
brks disulfide bond (gluten reducing agent) -> more extensible dough, retains CO2

Question 7

whci yeast: mix of yeast H20 oil ) emulsifier

Answer 7

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

Question 8

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bread machine yeast is ssimilar to ____

Answer 8

instant QUICK RISING active yeast bt w/ added ascorbic acid (a dough conditioner)

Question 9

which flour to choose?

pentosans

Answer 9

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

Question 10

salt firmen the gluten strucvutre

Answer 10

retards yeast femerntation -> longer dough rising time

Question 11

liquid: dissolve suagar + salt

Answer 11

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

Question 12

salt

Question 13

sugarL sources? excess/lil?

Answer 13

sugar nat in flour, E hydrolysing the starch, added
< fermentation time
excess, rise quicker ; too lil, delay the action of yeast

Question 14

fat softens bread & < shelf life TOR F

Answer 14

T
- < gluten extensibiliyt: good for vol good for txt

Question 15

oxidising agent such as ascorbic acid: how does it help w/ gluten dvlopment?

Answer 15

stripping H from sufylhydryl bond -> free S fro disulfide bond for gluten development
combine w/ reducing agent for optimal gluten dvlopment

Question 16

when mixing, air is incorp
do a test:

Answer 16

-> 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

Question 17

2ned step

when kneading gluten & gliadin adheres tgt. T or F.

Answer 17

F.
glutenin + gliadin -> creating a low elastic strand of gluten=> S S bond forms
starch traps into this

Question 18

3RD STEP :

what happes in first rise, dough is ripeened?

organic acids & ama created

Answer 18

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

Question 19

4TH STEP: punch down _ shape dough

gently handle, gently shape

Answer 19

1. subdivide the air cell, redistribute the yeast cells + food substrate -> equalise temp

gently handle to keep the gluten network on air cells

2. scaling [ divide dough into portions. -> gently shape & remove the large bubbles

Question 20

what is the last step before baking?
30-35 C & 85% humidity

Answer 20

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

Question 21

types of breads & doughs

Answer 21

1. 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

Question 22

to reverse staling & prioperly store

Answer 22

to reverse, toast @ 50-60C; can be done repeatedly til too much mositure loss
chilling promotes staling; freezing reverses it

Question 23

narrate staling: crumb toughens -> firmems -> loses

Answer 23

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

Question 24

when spoilage? what is meant when stated “inside of dough will become ropey”?

2 types of bacteria

Answer 24

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

Question 25

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

Answer 25

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