《食品發(fā)酵工藝》英文課件PPT,食品發(fā)酵工藝,食品,發(fā)酵,工藝,英文,課件,PPT Chapter 1 Strain Breeding Strain vs.Breedphysiological morphological Food microorganismsFood production microorganisms Produce new types of food Food spoilage microorganisms Cause spoilage of food and/or diseases3Use of MicroorganismsnPositivenProductionnConversionnNegativenPathogensnSpoilageFive Common Characteristics of Microorganisms1.Small volume,large surface area2.Fast absorption and conversion3.Rapid duplication and growth4.Strong adaptability5.Widespread distribution and diversified speciesWhat types of microorganisms cause fermentation to occur?nBacterianYeastnMold Bacteria Bacteria are typically one-celled organisms that multiply by simple division and can be seen only with a microscope.1.Lactic acid bacteriaLactobacillusyogurtStreptococcusyogurtPediococcussour picklesBifidobacteriumprobioticsLactobacillusStreptococcusPediococcusBifidobacterium2.Acetic acid bacteria Acetobactervinegar3.Glutamic acid fermentative bacteriumnCorynebacteriumglutamicumn nBrevibacteriumflavum Yeast Yeasts are unicellular(single-celled)fungi in which little or no mycelium develops and that ordinarily reproduce by budding.Happy YeastSaccharomyces cerevisiae 1.Saccharomyces Saccharomycescerevisiaebeer Saccharomycesellipsoideuswine 2.Candida CandidautilisSCPAbout SCP,which is correct?A.Is a kind of protein which extracted from microbial cells.B.Is microbial cell which produced by fermentation.C.Is antibiotics secreted by microbial cells.D.Could not be regarded as food.Mold(mould)Fungi that grow in the form of multicellular filaments,called hyphae.In contrast,microscopic fungi that grow as single cells are called yeasts.1.MucroC Chinese hinese cheesecheese2.Rhizopus amylase3.Aspergillus A.nigercitric acid,glucoamylase A.oryzaesoy sauce,pasta(sweet)saucespasta(sweet)sauces4.Monascus pigment Choosing Microorganismsfor Industrial Microbiology genetically stable easy to maintain and grow well suited for extraction or separationof desire productStrain SelectionPurchase from Culture CollectionsScreening of nature circumstances MutationsCell biology techniquesGenetic engineering International Culture CollectionsAbbreviationNameLocationATCCAmerican Type Culture CollectionUnited StatesIAM Institute of Applied MicrobiologyUniversity of Tokyo,JapanNCTCNational Collection of Type CulturesLondon,United kingdomChina Culture CollectionsCGMCCChina General Microbiological Culture Collection CenterBeijingCulture CollectionsScreening of nature circumstances Most major sources of microbes for use in industrial microbiology are natural materialsMicrobial strain collection 1.soil slurry 2.Enrichment Special media Control condition Inhibit unwanted strain3.Isolation cultivation Streak plate method Pour plate method Spread plate method Streak plate method nBacteria are“streaked”over the surface of an agar plate so as to obtain single colonies.nIt can also highlight the presence of contaminating micro-organisms.This is an example of a good streak for isolation using the four corners method.Performing a Plate Streak IPerforming a Plate Streak IIPour plate method Bacteria are mixed with melted agar.Poured into an empty plate and allowed to solidify.Spread plate method Small samples of the diluted bacteria are pipetted onto the surface of agar plates.A sterile,bent-glass rod is then used to spread the bacteria evenly over the entire agar surface.Performing the Spread Plate method I100Performing the Spread Plate method II70%EtOHKeep flame away from alcohol!4.Pure cultivationGrow only one kind of microbeMust use aseptic technique to avoid contaminating the cultureTransfer a single colony from agar plate to liquid medium5.Productivity measurement Primary screening：quantity Secondary screening：qualityIf I couldnt find an ideal strain from nature,how would I do?qSpontaneous(natural)mutationqInduced mutationmutationTechnique for inducing mutationPhysical mutagens e.g.X-rays,g g-rays,UVChemical mutagens e.g.base analogs,nitrous acid,alkylating agents How are mutants detected by scientists?nVisiblenNutritional(auxotrophic)nWhat is replica plating,and how is it used to detect auxotrophic mutants?nResistance mutations(plate on media containing the chemical)Replica-plating technique to screen for mutant strains of a colony-forming microorganism.Q:How would you select for L-tryptophan-producing mutant strain?Cell Biology TechniquesnProtoplastnRemoving the cell wall with lytic enzymes in the presence of osmotic stabilizers.nIn the presence of fusogenic agent such as polyethylene glycol(PEG),protoplasts are induced to fuse and form transient hybrids or diploids.nRegeneration of viable cells from the fused protoplasts.Genetic EngineeringVarious high value added products have been produced fromgenetic engineeringmethods.Inoculum Development The preparation of a population of microorganisms from a dormant stock culture to an active state of growth that is suitable for inoculation in the final production stage.If fermentation in a large tank receive only one loop of inoculum,a prolonged period would result.energy consumingcontamination Necessity of inoculum development So the inoculum volume has to be quite largeA seed fermenter is usually required to produce the inoculum volumeThe seed fermenters purpose is not to produce product but to prepare inoculumIn inoculum developmentInoculum level:approximately 0.5 to 5 percent inoculum by volume from the preceding step.Incubation period:short,in log growth phase,little fermentation productInoculum media:balanced for rapid cell growth and not for product formation.The process of inoculum developmentInoculation of a fermenter from another seed tankSeedTankFermenterA BTrap TrapSteamCJDIHEFGIndustrial Fermentation Setting Review Questions1.Cite some micro-organisms used widely in food industry and their corresponding products.2.How to get an ideal strain for fermentation industry?3.Whats the purpose of inoculum development?Cite the process of it.4.Why can not the micro-organisms product excessive metabolites spontaneously?By which methods can we get the excessive metabolites?5.How to reduce the concentration of end products in fermentation?6.How to improve the permeability of cell membrane?Chapter3SterilizationUnit1MediumSterilizationUnit2AirSterilizationBasictermsSterilizationDisinfectionAntisepsisBacteriostasisAsepsisSterilizationDestructionofallformsofmicrobiallife,includingbacterialspores.MorethoroughthandisinfectionDisinfectionTokillmostofmicrobialformsexceptsomeresistantorganismsorbacteriumspores.e.g.useofalcoholbeforedruginjection.Aboutsterilizationanddisinfection,whichiswrong?A.A.Sterilizationisthekillingofallmicroorganismsinamaterialoronthesurfaceofanobject.B.B.Disinfectionmeansreducingthenumberofviablemicroorganismspresentinasample.C.C.Typicallythelastthingstodiewhenoneattemptssterilizationisthehighlyheat-(andchemical-,etc.)resistantendospores.D.D.Alldisinfectantsarecapableofsterilizing.AntisepsisProcessofinhibitingorpreventinggrowthofmicrobes,mostlyin vitroandnotbactericidalorsporicidal.e.g.useofchemicalagentsonskinetc.Bacteriostasis Processofinhibitingthegrowthofmicroorganisms,in vivo(mostly)orin vitro.e.g.bacteriostaticantibioticsDifferent Kinds of Bacteria“Death”1.Bacteriostatic2.Bacteriocidal3.BacteriolyticLog Cell#TimeTotal cell countViable cell countAsepsis Nolivingmicroorganismsexists.e.g.OR(OperatingRoom)SterilizationconvenientlycategorizedasfollowsI.PhysicalmethodsHeat:Dry heat Moist heatRadiationsUltraviolet radiationsIonizing radiationsFiltrationII.Chemicalmethods1.Chemical agents Alcohols,Chlorine,FormalinSuitableforskinandinstruments2.Radiation3.Dry HeatUltravioletandIonizingRadiationSuitableforsterileroomandinoculationhoodDirect flaming:e.g.inoculatingloopHot-air sterilization:160,2hinhotairoven4.Moist Heat121121，30min 30min inautoclaveSuitableformediumandinstruments5.FiltrationRemovalofbacteriabyfiltermediumUsedforheatsensitivematerialsandfiltratedairFlamingHotairoven -170 C for 1 hour -140 C for 3 hours.DryHeat1.Pasteurization(below100C)Destroyspathogenswithoutalteringtheflavorofthefood.Lowtemperature(holdingmethod):63,30minHightemperature(flashmethod):72,20secMoistHeat2.Boiling(at100C)-killingmostvegetativeformsofbacteria-10minorlongertime3.Autoclaving(above100C)-killingbothvegetativeorganismsandendospores-121-132oCfor15minorlongerMoistHeatvsDryHeatMoistheatDryheatPenetratingpotency higherlowerTemp.forproteinclottinglowerhigherExtraheatreleasedyesnofromcondensationSterilizingpotency:Moistheat DryheatWhyismoistheatmoreefficientthandryheat?Conductivity.Moistureconductstheheatbetterthanadrysystem.dryheatormoistheat?A.is less penetrating and requires longer exposure.B.An autoclave is a high pressure device used to allow the application of above the normal-atmosphere boiling point of water.C.Pasteurization is the application of of less-than boiling temperatures to foods to prevent the growth of food-spoiling organisms as well as various heat-labile pathogens.Cannedfoodcouldbestoredforalongtime,because A.Bacteriacantgointocan.B.Bacteriacantbreathincan.C.Therearenobacteriaincan.D.Bacteriacantsurvivalincan.SterilizationprocessesBatchsterilizationContinuoussterilization Batch sterilization uses steam or direct firing to elevate the temperature,and then cooling water stops the process and brings the material back toward room temperature.BatchsterilizationBatchsterilizationwastesenergyandcanovercookthemediumContinuoussterilization is used to almost eliminate these undesired times because there can be more rapid heat transfer to flowing medium in pipes.ContinuoussterilizationAlso called high temperature short time(HTST)Generally carried out at 140C,whereby sterilization times of 2-3 min are sufficientfermentorstreamstreamCoolingwaterSterilemediummixingtankpumpsterilizingcolumnMaintainingtankcoolingpipeWhataretheequipmentsofcontinuoussterilization?QuestionContinuoussterilizationprocessesInjectionsterilizersSteamisfeddirectlyintorawmedium,sothattemp.risestodesiredlevelalmostimmediately.AdvantagesShorter sterilization time means less thermal degradation of medium.DisadvantagesInsufficient for sterilizing media containing solid matter,on account of inferior rate of heat-transfer in solids.(batch process is recommended for sterilizing such media.)BatchandContinuousSterilizationInaword:Hightemperaturesforshorttimesareusedinpreparingnutrientmediaforindustrialfermentationsandinpasteurizingmilk,becausethiscauseslessdamagetobiochemicalsthanmoreprolongedtimesatlowertemperatures.Filtration Sterilizesolutionsthatmaybedamagedordenaturedbyhightemperaturesorchemicalagents.The pore size for filtering bacteria,yeasts,and fungi is in the range of 0.22-0.45 m(filtration membranes are most popular for this purpose).Filtration:Fluids&AirUnit2AirSterilizationVerylargevolumesofsterileairisrequiredinmanyaerobicfermentationprocess.MethodsforairsterilizationRadiationHightemperatureElectrostaticbacteriaremovalFiltration Airsterilizationisgenerallycarriedoutbyfiltrationtoremoveallparticlesandm/o(bacteria,spores,yeast,mould)fromatmosphericflow.Forreasonofcost,absolutesterilityisneitherpossiblenorcustomaryinpractice.n For germ-filtration of liquids(hydrophobic membrane filters),the pore width is 0.2 m.n For air-filtration,the pore width of filters is over 0.45 m.Removalofm/ofromairbythefibrousfiltermayoccurbyone,orcombinationofthefollowingmechanisms:Inertial impactionInterceptionDiffusionElectrostatic attractionSize exclusionRemoval mechanisms DiffusionalInterception ElectrostaticAttraction Inertial impactionDepthFiltersFibrous material(cellulose,synthetic fibers,glass fibers)Granular material(activated charcoal)Air outletSupport gridStainless steel casingFibrous filter packingSupport gridAir inletSimple air filterContaminantsinCompressedAirAtmospheric dust,smoke,fumes,water vapour,bacteria and viruses!Oil carried over from the compressor.Solid contaminants generated within the system.TheproposeofairpretreatmentMakingairmoreclean-upperaircollectingpipe-coarsefilterOilandwaterdischargeThe process of air filtrationexample1.Coarse filter 5.Cyclone separator 2.Air compressor(120 150)7.Wire mesh demister 3.Recover tank 8.Heater(30 35)4.6.Cooler(20 25)9.FilterCycloneseparatorwire mesh demister or wire mesh mist eliminatorsAllaircompressorscreatecondensate.Duringtheactofcompression,theairtemperatureisraisedwhichincreasestheairsmoistureholdingcapacityandpreventscondensation.However,whenthecompressedaircoolsintheaftercooler,air-receiver,piping,etc,thedewpointisreachedandcondensationoccurs.180M180M3 3 Fermenter PlantFermenter PlantAirCompressorAir Filters in Fermentation PlantMethods used in food preservationMethods used in food preservationFreezingOsmoticpressure(additionofsaltorsugar)OxygendeficitAcidDry(desiccation)AntisepticagentFoodPreservation Killorganisms:canning,pasteurization,cooking,irradiation Inhibitgrowth:refrigeration,freeze,dehydration,lower pH,high salt or sugar,chemicals01036.56072100BoilingPoint PasteurisingTemperature Freezer Fridge BodyTemperature Temperature zonesSAFETY SAFETY DANGERDANGERReviewQuestions1.Tell the difference between sterilization and disinfection,batch sterilization and continuous sterilization(describe the advantages and disadvantages respectively).2.State the procedures of continuous sterilization and the process of air filtration.Tell the functions of each equipment.HappyNationalDay Chapter 2 Preparation of Culture Medium Unit 1 Industrial Fermentation Medium The basic ingredients of media include carbon source、nitrogen source、inorganic salt、growth factor and distilled water etc.MediumDevelopmentnTo maintain economic competitiveness,low-cost crude materials are frequently usednLevels of minerals and growth factors may be criticalKinds of Culture MediaThe source of media constituent ComplexmediaSyntheticordefinedmediaSemi-definedmediumPhysics statesLiquidmediumSolidmediumSemi-solidmediumFor useBasicmediumEnrichedmediumDifferentialmediumSelectivemediumManufacture intentionSeedmediumFermentmediumNutrient sources for industrial fermentationCarbon&energysource+nitrogensource+O2+otherrequirementsBiomass+Product+byproducts+CO2+H2O+heatNutrientRaw materialCarbonmolasses,starchNitrogencornsteepliquor,soybeanmeal,pureammoniaorammoniumsalts,urea,nitratesalts,phosphatesaltsVitaminsandgrowthfactorsbiotin,yeastextract,beefextract,cornsteepliquor,wheatgermmealFermentationmedia1.Carbon sources (1)Starch(corn,wheat,potato)Widely used in fermentation industryStarch dextrin glucose Advantages:cheaper than glucose(2)MolassesByproduct of cane or beet sugar productionA dark viscous syrup containing 50%-75%fermentable sugars(mainly sucrose)with 2%nitrogen,vitamins and mineralsCheaper 2.Nitrogen source (1)Inorganic nitrogen source Ammonia,ammonium and nitrate Microbes can utilize it faster.After it is utilized,the pH of medium will be changed.(NH4)2SO4 2NH3+H2SO4 NaNO3+4H2 NH3+2H2O+NaOH(2)(2)Organic nitrogen sourcesUreaYeast extractPeptonesCorn steep liquorSoybean cake powder Peanut powderBran hydrolysis liquidcornsteepliquorpowder3.Trace elements Fe,Mn,B,Zn,Cl,Mo,Cu4.Growth factors Small amount of organic compounds necessary for microbial growth.e.g.amino acids,vitamins,biotin Sources:normally organic nitrogen source e.g.corn steep liquor Corn steep Liquor,CSLnCorn steep liquor is the water extract by-product resulting from the steeping of corn during the commercial production of corn starch and other corn products.Different medium for different food productsChinesedistilledspirit：solidmediumFruitspirit：fruitjuiceorfruitsauceBeer：wortAlcohol:starchmashAminoacid:starchmashCitricacid：starchmashLacticacid：starchmash Unit 2 Preparation of Starch Sugar Starchisalargemoleculethatismadeofbranchingchainsofglucosemolecules.Itcanbebrokendownintoglucosebyhydrolysis.nStarchfoundingrains,potatoes,beans,peas,cassavanTypically20-30%amylose,remainderamylopectinCharacteristicsofstarchInsolubleinhotwaterBluecomplexcompoundbyreactionwithiodine.Insolublein30%ofethanolsolutionorabove.Hydrolyzedbyacidandenzyme,theultimateproductisglucose.starch granuleIV.A.ii.-20Starch:AmylosenAmyloseisalinearglucanwith1,4glycosidiclinkagesIV.A.ii.-21Starch:AmylopectinnAmylopectinisabranchedglucanwith1,4and1,6glycosidiclinkagesStarch:Amylopectinnlessextended(morecompact)thanamylosenlargerMW 1,6 linkages 1,6 branch points result in tree-like structureWhy should starch be hydrolyzed to glucose?1.Mostmicrobescouldnotutilizestarchdirectly.2.Toobtainsugarfromthestarchofmanydifferentplants,ratherthanjustsugarbeetsorsugarcane.Conversion of starch to fermentable sugars 1.Acid hydrolysis method Starch slurry is acidified to a pH value and then heated in a converter under pressure.(C(C6 6H H1010O O5 5)n n (C(C6 6H H1010O O5 5)x x C C1212H H2222O O11 11 CC6 6H H1212O O6 6 amylumdextrinoligosaccharidesglucoseDue to heat and acid,there are Glucose combination reaction combination reaction and and decomposition reactiondecomposition reactionstarch glucose oligosaccharidecolourcontent(difficult to utilize)(difficult to decolor)Total lost of glucose 7 7 1shortening the starch(Liquefaction)glucoamylase-produces glucose(saccharification)glucose isomerase-convert to fructose(isomerization)3.Acid-enzymecombinationmethod(Two-stagehydrolysis)Slurryisonlypartiallyconvertedbyacidandthentreatedwithanappropriateenzymeorenzymesuntiltheconversioniscomplete.1)Acid-enzyme hydrolysisAcid-liquefactionGlucoamylase-saccharificationSuitable for:starchgranuleishard2)Enzyme-acid hydrolysis-Amylase(thermostable)-liquefactionAcid-saccharificationSuitable for:starchgranulesizeisirregularProduction of Glucose from StarchItemsItemsacidacidacid/enzymeacid/enzymeenzymeenzymeDEDE valuevalue919195959898ColorColor10100.30.30.20.2Processingcondition HTPHTPNTPEnergy consumingEnergy consuminghighhighhighhighlowlowBy-productBy-productmoremoremoderatemoderatelittlelittleCycle time Cycle time shortshortmoderatemoderatelonglongReview Questions1.Whichkindofcarbonsourceandnitrogensourceusuallyusedinindustry?Citetheadvantagesanddisadvantagesofthedifferentchoices.2.Whatisthedefinitionofgrowthfactoranditsmainsource?3.Whatisthesignificanceofgettingsugarbyhydrolyzingstarch?4.Comparethethreemethodstoproduceglucosefromstarchandthedifferencebetween combinationreactionanddecompositionreaction,liquefactionandsaccharification.InductionRepression1.Itturnstheoperonon.1.Itturnstheoperonoff.2.Itstartstranscriptionandtranslation.2.Itstopstranscriptionandtranslation.3.Itiscausedbyanewsubstance,whichneedsenzymestogetused.3.Itiscausedbyanexcessofexistingmetabolite.4.Itoperatesinacatabolicpathway.4.Itoperatesinananabolicpathway.5.Repressorispreventedbytheinducerfromjoiningtheoperatorgene.5.Repressorisenabledbyaco-repressortojointheoperatorgene.Feedback repressionFeedback inhibitionRegulationlevelgenetic:RNAtranscriptioncellular:activityofenzymeComplexformedendproduct+repressorendproduct+enzymeEffectoperatoronDNAtemplateoccupiedbythecomplexreducedenzymeactivityConsequenceblockedtranscriptionTherespectivereactionisinhibited.