Baker’s yeast production

This presentation this gives detailed account on Baker's yeast production

1. BAKER’S YEAST
PRODUCTION
Made by Ms. MANASI MORE
Mentor Ms.RENU NK JAISINGHANI

2. ➢HISTORY OF BAKER’S YEAST
PRODUCTION
▪Inoldendaysinoculumfromprecedingfermentationwasusedindoughforbread
making.It’sstillusedatconsiderableextentbutitisnotpracticalbecauseyeast
growveryslowly,thereforedoughhastobeinoculatedwithlargenumbersof
yeastandthesemisolidelasticnatureofdoughmakesitdifficulttostoreand
transfer.
▪Itistherefore,verymuchessentialforbakingindustrytohavelargescale
commercialsourceofyeast,whilethebrewer’syeastincreases5to10timesin
volumeduringbeerandwineproduction,butincaseofbaker’syeastthereis
verylittlegrowthindoughduringshortperiodofbaker’sfermentation.

3. ➢ORGANISM:
SpecialstrainofS.cerevisiaeisusedanditshouldhavefollowingproperties:
▪Uniformbiochemicalstability
▪Abilitytofermentflourdoughvigorously(excellentdoughraisingcapability)
▪Abilitytodisperseeasilyinwater.
▪Goodkeepingquality(resistautolysis).
▪Preservationatroomtemperaturewithoutanychangeinpropertiesand
appearanceshouldbepossible.
▪Shouldgivebetteryield.
▪Highergrowthrate.
▪Abilitytowithstanddrying.

4. ➢RAWMATERIAL:
➢C-source:Commonlyusediscaneorbeetmolasses,
becauseyeastbeinginvertasepositivecanassimilate
invertsugar ormixtureofcane(20%)and
beet(80%)molassesisusedasitsuppliesyeastwithbios
factor for growth. Other sources are
grains,whey,hydrocarbon,SWLetc.
▪Concentrationofsugarshouldbeadjustedtoget
maximumcellulargrowththanethanolproduction,so
0.5-1.5%sugarisused(highsugarconcentration
preventsrespirationeveninpresenceofexcessof0
2).
Thusbyslowandintermittentadditionofsugaris
essential.

5. ➢RAW MATERIAL:
▪N-source:Themostcommonareammoniumsalts,liquidNH
3or
Urea.Cornsteepliquor(CSL)canalsobeusedbutnotNO
3and
NO
2
▪P-source:Thecommonsourcearephosphoricacid,diammonium
phosphate.Itisverymuchessentialforfastgrowthandgood
performanceinfermentation.
▪Mg++fromMgSO
4isusedanditpreventsautolysisofcells.

6. ➢RAWMATERIAL:
▪Traceelements–Fe,Zn,Cu,MnandMoarerequired.
▪Vitaminsorbiosfactors-Itisrequiredforoptimum
growth.Biotin,panthothenicacid and required
concentration0.29ppm,50ppmand1200ppm.Sometimes
thiamineisadded,asitimprovesactivityofcompressed
yeastindoughsystem.

7. ➢PRODUCTION OF BAKER’S YEAST:
❑INOCULUM DEVELOPMENT
Stock culture on slant
A loopful St. Molasses with 6% sugar
25*c , ph. 4.5anaerobic,12hrs Tank 1
Tank 2
fermenter
20% inoculum Tank 4 Tank 3
▪At every stage from seed tank 1 tank 4 sugar concentration is increased from 6% to 10%.
▪Stainless steel tanks are used as pH is acidic, any other metal fermenter like Cu may cause
solubilization of metals ions in the medium & that may affect growth of organism.

8. ➢FERMENTATION CONDITION :
▪Temprature-28-30
0
C,thereforeefficientcoolingsystemisrequired.
▪pH-4.5-5.0,itisadjustedbyaddingphosphoricacid.LowerPHprevents
containment,butatverylowPHyeastcellmayabsorbcoloringmaterialfrom
molasses.Thisaffectscoloroffinalproduct.TopreventthispHisraisedby
additionofammoniaoralkaliatendoffermentation.
▪Coolingsystem:Largeamountofheatisreleasedduringaerobicfermentation,
thustomaintaintemperature(at28
0
to30
0
c)coolingsystemisrequired.
❑AERATIONANDAGITATIONSYSTEM:
▪Itisveryessentialasvegetativegrowthofyeastisfavoredunderaerobic
conditionatlowsugarconcentrationandhighaeration,maximumrespiration
andtherebycanbeachieved.

9. ➢ADDITIONOFSUGAR:
▪Productionismainlydoneby‘Fedbatchfermentation’and
carriedoutwithincrementalfeedingofthesubstanceforgrowth
speciallytopreventglucoseeffect.
▪Intermittentadditionisdonetomaintainsugarconcentrationat
lowlevelthatcanfavorrespirationandnotfermentation.
▪Theirisnosimultaneousremovaloffermentationcontentand
fermentationisfinishedwhenfermenterisfull.
▪Theadditionofsugarisreducedattheendoffermentationin
orderto“mature”theyeast,asmaturedcellsmayhavelower
fermentationactivitybutbetterstoragestability.

10. ▪Nutrientaddition-Sugarisaddedintermittentlytomaintainits
concentrationat1.5%sothatorganismsgrowwithoutfermentation
orethanolproduction.Ethanolproducedshouldbe0.055orless.Itis
stoppedattheendoffermentationformaturationorripeningi.e.
numberofbuddingcellsintotalpopulationshouldbelessthan5-10%
▪Cooling-usingcoolingcoilstopreventincreaseintemperature.
▪Yield-4to6%yeastsolidisobtained

11. ➢YIELD:
▪6%yeastconcentrationisobtainedbut10%canbe
obtained.But10%yeastsolidoccupy25%ofliquid
fermentervolumeandsuchbrothcannotbepumped
atallthatisthereisalwaysapracticallimittothe
concentrationofyeastsolidthatcanbeachievedin
thefermenter.

12. ➢HARVESTING OF YEAST CELLS/RECOVERY:
▪Brothiscooled.
▪Yeastcellsareseparatedbysedimentationorcentrifugationtotripletheyeast
concentration.
▪Thewhitecoloredpumpableliquidthatisobtainediscalledyeastcream,itis
furtherconcentratedbyfiltration(usuallybyplate&framefilterorRVFisused).
▪Duringfiltrationsaltsmaybeaddedforosmoticeffect,thissaltisthenremoved
bysprayingwaterdirectlyonfilterthusresultingcrumblymassofyeastcell
calledaspresscake.Ithas27to28%yeastsolid.
▪ThefinalproductcanbeinformofCDY(Compressed DryYeast)or
ADY(ActivatedDryYeast)

13. ➢Plate and Frame Filter
https://www.youtube.com/watch?v=M4wBd1_CvNw

14. ➢COMPRESSED DRY YEAST (CDY):
▪The yeast press cake is mixed in blender with small amount of
emulsifier or cutting oils at concentration 0.1 to 0.2 %.
▪Function of emulsifier : Facilitate extrusion, give better, lighter
appearance to yeast cake
E.g. -Monoglycerides, Diglycerides, sorbitol esters or lecithin
▪Yeast press cake is now extruded through nozzle in the form of
thick strands with rectangular cross section.
▪These are then cut into appropriate length Wrapped in wax
paper
▪Packed and marketed

15. ➢COMPRESSED DRY YEAST (CDY):
▪Immediate rapid cooling is required after packaging because
the mass warms up during processing. This is done by
refrigerating with rapid supply of cool air for 24 to 48 hrs.
▪Final product is stored at refrigeration temperature 5 to 8
0
c
(stability depends on condition during processing & % of
budding cells)

16. ➢ACTIVATEDDRYYEAST(ADY):
▪Itisproductofdriedyeastcellswithoutlossofviabilitywith8%
moisture.
▪Yeastpresscakeispassedthroughscreentogettinypellets
whicharedried(tunneldrierorrotatorydrier)at28to40
o
cfor2
to4hours.Evenfluidizedbeddrierscanbeusedtodryproduct
within1to2hrs.
▪Butylatedhydroxyanisole(BHA)isaddedat0.1%concentration
toprovideprotectionfromoxidativedeterioration.Thisalso
improvesstability&keepingqualityofproducttogreaterextent,
thereforeproductiscalledProtectedADY.

17. ❑COMMON CONTAMINANTS :
▪Lacticacidbacteria–Leuconostoc&lactobacillus&molds.
❑STABILITYOFADY:
▪ADYispackedwithoutprotectivepackaginginpolyethylene
linedbags,loses7%activitypermonth&hasstoragelifeof1to2
years,butifpackedundervacuumthenlosesonly1%activityper
month

18. References
◦CasidaL. E., "Industrial Microbiology” (2009) Reprint, New Age International
(P) Ltd, Publishers, New Delhi.
◦Prescott and Dunn's ‘’Industrial Microbiology’’(1982) 4th edition, McMillan
Publishers

19. THANK YOU