amb traditional beer.pdf

AMB232 TRADITIONALAFRICANBEERS Fermentationisoneoftheoldestmethodsusedbymantoprocessandpreserveagriculturalproducts.Inad ditiontoprolongingshelf- life,fermentationconfersmanybeneficialeffectssuchasprobioticsattributes,enrichmentofessentialnu trients,improvementinsafety,organolepticcharacteristics,di...

AMB232 TRADITIONALAFRICANBEERS Fermentationisoneoftheoldestmethodsusedbymantoprocessandpreserveagriculturalproducts.Inad ditiontoprolongingshelf- life,fermentationconfersmanybeneficialeffectssuchasprobioticsattributes,enrichmentofessentialnu trients,improvementinsafety,organolepticcharacteristics,digestibilityandedibility,andreductionofv olumeandcookingtimeoffermentedproducts. Spontaneouslyfermentedsorghumbeersremainbyfarmostpopulartraditionalcereal- basedalcoholicbeverageinAfrica.Knownundervariouscommonnames(traditionalbeers,sorghumbe ers,opaque,nativeorindigenousbeers)theyarealsorecognizedundervariouslocalnamesdependingont heregionorethnicgroup.Theselow- alcoholicbeersarenutritiousandcontributetothenutritionalbalanceoflocalpopulations,aswellastheirs ocio-culturalandeconomicwell- being.TheproductionofAfricantraditionalbeersremainsoneofthemajoreconomicactivities,creatinge mploymentandgeneratingsubstantialincomethatcontributestolivelihoodsaswellasthecountry’secon omicsystems.Theirprocessing(maltingandbrewing)isstillartisanal,basedontraditionalfamilyknow- how.Thebrewingprocessinvolveseitheranacidificationandanalcoholicfermentationphases,oramixe dfermentationcombiningLacticacidbacteria(LAB)andyeasts.Saccharomycescerevisiaehasbeenide ntifiedasthedominantyeastspeciesinvolvedinthealcoholicfermentation,LABinvolvedbelongtotheg eneraLactobacillus,Lactococcus,StreptococcusandEnterococcus.Molds(Aspergillus,Penicillum,a ndRhizopus). ChallengesforsustainableproductionofAfricanbeersinclude,inconsistentsupplyofrawmaterial,varia bilityinproductqualityandshortshelf- life.ForsustainableandenvironmentallyfriendlyproductionofAfricanbeers,thereistheneedtoassessth eprocessingmethodsandaddresssustainabilitychallenges.Strategiesshouldpromotewiderdistributio nandadoptionofimprovedsorghumvarietiesamongfarmers,preventlossesthroughtheadoptionofgoo dstoragepracticesofrawmaterial,andpromotetheadoptionofimprovedcookstovesbythebrewers,deve lopandadoptstarterculturesforcontrolledfermentation,regulatetheproductionthroughtheestablishm entofqualitystandardsandbettervalorizeby- productsandwastestoincreasethecompetitivenessofthevaluechain.Appropriatepackagingandstabili 1 zationprocessesshouldbedevelopedtoextendtheshelf- lifeanddiversifythechannelsforsustainabledistributionofAfricacereal-basedalcoholicbeverages. Traditionalmethodsforfermentationthatyieldedalcoholicbeveragesindevelopingcountriesandindee dAfricahaslongbeeninexistence- sinceprehistorictimes.Amongstthese,(primarilyforemphasis)areburukutuandpito(takenmajorlyin WesternAfrica),‘Urwaga’inKenya,‘Kasiksi’inDRCongo,‘Lubisi’inUgandaand‘Urwagwa’inRwan daandBurundi,TejinEthiopia,‘Mes’inEritreaand‘iQhilika’and‘Khadi’oftheXhosaandTswanapeopl eofSouthernAfricarespectively. Africantraditionalbeermaygenerallybedefinedasnon- clearbeermadefromsorghumormaltwithanalcoholicstrengthofusuallylessthan5%/v. SomeAfricanTraditionalBeer Pito PitoisanartisanalalcoholicbeerwidelyconsumedinWestAfricancountries,especiallyinNigeria,Ghan aandsomepartsofNigerRepublicanditprovidesasourceofincomeformanyinruralareas.Theingredient srequiredfortheproductionofpitoarereadilyavailableinlocalcerealmarketsorcouldbecultivatedindo mesticfarmlands.Theseingredientsaremaize,sorghum,driedsweetpotatoesandinGhana,thereisthead ditionofokrastemwhichfacilitatesthesedimentationofinsolublemash.Thebeverageismadefrommalt edsorghumormilletgrainsoracombinationofbothandtheproductionprocessinvolvesmalting,ferment ationandthenmaturation.Thebeerhasaveryshortshelflifeandisnormallyconsumedwithinadayafterpr oduction. Traditionalpitopreparation: Sorghumgrainsarewashedandsoakedinwaterfor24hours,drained,andkeptfor2daystogerminate.Afte rsprouting,thegrainsaresun-driedandgroundintoaflour.Theflourismixedwithwaterandboiledfor3- 4hourstoformaslurry.Theboiledmashisallowedtosettle;waterisdecantedwhilethesedimentisrecooke dinwaterforanotherthreehours.Aftercooking,themixtureisallowedtostandatroomtemperaturefor24 hours,afterwhichmorewaterisaddedandthemixturereheatedfor3hours.Thecooledcookedmashisfilte redandallowedtostandovernighttillthetastebecomesslightlysour.Thefiltratethatwasleftovernightist henboiledtoformaconcentrate.A“starter”whichistheleftoverofthepreviousbrewisaddedtothecooled concentrateandleftfor24hours.Theproductispito,adark- 2 brownliquidwithtastevaryingfromsweettobitter.ThesestepsfortheproductionofpitoareshowninFigu re1 WashingandsoakingofSorghumgrainsovernight ↓ Grainsaredrainedandkeptfor2daystogerminate ↓ Maltedgrainsaresundriedfor3-5days ↓ Grindingofsundriedgrains ↓ Mixingwithwaterintomashandboiledfor3-4hourstoformslurry ↓ Decantingofthesupernatantslurryuponcooling ↓ Re-boilingofthesedimentfor3hours ↓ Decantingofthesupernatantslurryuponcooling ↓ Additionofwatertosupernatantandlefttostandfor24hours ↓ Furtherfiltrationandlefttostandtilltastebecomesslightlysour ↓ Additionofstarterandlefttostandfor24hours ↓ Pito Figure1.Pitoproduction Microorganismsassociatedwithpitoproduction: Therearecertainmicroorganismsassociatedwiththecerealgrains(sorghumormaize)usedfortheprodu ctionofPito.TheyareRhizopusoryzae,Saccharomycescerevisiae,Aspergillusflavus,Penicilliumfunic ulosum,Penicilliumcitrinum,GiberellafujikuroiandBotryodiplodiatheobromae.Also,thestarterused intheproductionofPitohasbeenobservedtohavemicroorganismssuchasGeotrichumcandidum,Candi 3 dasp.andLactobacillusspp.whichwerefrequentlyisolatedwhileAspergillusversicolor,Peinicilliumsi mplicissimumandPenicilliumpurpurogenumoccurredoccasionally.Fungihavebeenobservedtoplaya vitalroleinthehydrolysisofstarch.Rhizopusoryzae,Aspergillusflavus,Penicilliumfuniculosum,Penic illiumcitrinumhavebeenshowntobesaccharifyingagentsandassistthemaltingprocess. Burukutu ThisisalocalbeerconsumedmainlyinthenorthernandmiddlebeltregionofNigeria.Itisthefermenteddri nkcalled‘burukutu’.Thedrinkismadesimilarlytopito,withthesamematerialsbutwithslightvariationsi ntheproductionprocess.Bothdrinksareconsumedwithinsamecommunitiesandaredistinguishedbase doncolourofthefinishedproduct,aromaandthetastewithBurukutuhavingastrongervinegaryflavour.B urukutuconsumptionismuchhigheramonglow- incomeearnersinWesternAfricaandistakenallyearround. IngredientsforproductionofBurukutuaresorghumgrainsormillet,maizewhichcanbesourcedtradition allyfromcerealandgrainsmarket.Therehasalsobeenasurgeinthecultivationofthesecrops. Traditionalburukutuproduction: TheproductionofBurukututraditionallyissimilartotheproductionofPitointheprocessingandrawmate rialsinvolved.Thestepscanbecategorizedbroadlyintothreenamely;malting,fermentationofmash- garrimixtureandthematurationprocess. Duringthepreparation,sorghumgrainsaresteepedinwaterovernight.Thegrainsarethenpouredintoaba sketandthewaterisallowedtodrainoffforabout2hours.Thegrainsarespreadoutonleavesormatsinabed ofabout3- 4inchesinthicknessandcoveredwithanotherlayerofleaves.Duringthismaltingperiod,thegrainsarewat eredonalternatedaysandoccasionallyturnedover.Germination,whichstartswithin24hoursaftersteepi ng,isallowedtocontinueforaperiodof4- 5days.Thelengthofplumuleisusedinjudgingwhengerminationhasgonefarenough.However,germina tionisusuallycompleteafteraperiodof4days.Aftergerminationthemaltisspreadinthinlayersinthesunt odryfor1or2days.Thedriedmaltisgroundintopowder.Inthenextstage,gari(astarchypowderproducedf romthetuberofcassavaplant,Manihotutilissima)isaddedtoamixtureofthegroundmaltandwaterandsti rredwithastick.Theresultingmixture(gari-maltpowder- water)isroughlyintheratio1:2:6byvolume.Themixtureislefttofermentfor2days.Attheendoffermenta 4 tion,themixtureisboiledforabout4h.Thedrinkisthenlefttomatureforanotherperiodof2days.Theendpr oductisasuspensionofsomeparticlesinacreamyliquid. TheflowdiagramfortheproductionofBurukutu. Cereal(5kg)grains ↓ Soakedinwaterfor24hours ↓ Draining ↓ Germinationfor2daysat28°C ↓ Sun-dryingofgerminatedgrains ↓ Grindingintoflour ↓ Waterisadded ↓ Boilingfor3-4hours ↓ Slurry ↓ Settling ↓ Decantation ↓ Freshwaterisaddedandreheatedfor3hours ↓ Coolingandseparation ↓ Sediment ↓ FreshBurukutu ↓ Flavourdevelopmentincalabashfor24hoursatroomtemperature ↓ Burukutu Figure2.ProductionofBurukutu. Microorganismsassociatedwithburukutuproduction: Thesorghummaltsusedastherawmaterialsfortheproductionofthebeerhostavastarrayofmicroorganis msthatrangedfrombacteriatofungi.TheseareSaccharomycescerevisiae,Canndidatropicalis,Candid 5 akrusei,Hansenulaanomala,Rloeckeraapiculate,Mucorrouxii,Aspergillusflavus,Aspergillusoryza e,Lactobacilluslactis,Lactobacillusdelbriickii,LactobacillusplantarumandStreptococcuslactis. Thefermentationofthemixtureofthemashandgarriwasalsoattributedtothefunctionofamicrofloraofor ganisms(communityofmicroorganisms)theyareSaccharomycescerevisiae,Saccharomyceschevalie ri,Candidatropicalis,Candidaguilliermondii,Candidamycoderma,Hansenulaanomala,Leuconosto cmesenteroides,Lactobacillusplantarum,Lactobacillusbrevis,LactobacillusdelbruckiiandLactoba cillusfermenti.ThisaccountsforthedropinpHduringthefermentationprocessfrom6.4toabout3.7after4 8hoursatroomtemperature. Atthematurationstage,themicrofloraofmicroorganismswereSaccharomycespastorianus,Hansenul aanomala,Candidamycoderma,Candidatropicalis,Kloeckeraapiculate,Lactobacilluspastorianus, Acetobactercapsulatum,Acetobacterrancens,AcetobacterviscosumandStreptococcusmucilaginosu s. BurukutuhasshownahighprevalenceofEscherichiaandStaphylococcuspossiblybecauseofitsphysico chemicalpropertiesthatallowbacteriatothrive.TheprevalenceofSaccharomycesisexpectedbecauseo fthesugarfromtherawmaterialavailableforfermentation.Again,Aspergillusprevalencemaybeasourc eofaflatoxinsandithasbeendemonstratedtobepresentinthedrink. KaffirBeer KaffirbeeristhetraditionalbeveragedrinkoftheBantupeopleofSouthernAfrica.Kaffirbeerisanopaque ,effervescentbeerwithyeastyodourandfruityflavour.Itispinkduetosorghumtannins.Itcontainsanaver agealcoholcontentof3.2%andlacticacidcontentof0.3%.Thebeermustnotcontainaceticacid.Ifabeerc ontainslittlealcoholbutiswellsoured,itisstillveryacceptable.Kaffirbeerismadefrommaltedkaffircorn (sorghum)andunmaltedmaizeandkaffircorn.Milletsmaybeusedinplaceofthese. Productionofkaffirbeer: Cleanedandwashedkaffircorngrainsaresteepedfor8- 24hours,thendrainedandspreadoutinlayerstogerminate(atabout30°C)for5- 7days.Thegrainsarewateredforthefirst3daysandtheyareturnedandcoolairusedtoreduceheat.Germin ationcontinuesuntiltheplumuleis(2-5cm)(1-2in)inlength.Theyarethensun- 6 driedordriedinanovenat50-60°Candground.Thefinishedmaltcontainsβ-amylase(30-40%),α- amylase(60-70%)anddiastaticpowerof11.6- 17.2(Lintner).Themainstepsinkaffirbeerbrewingaremashing,souring,boiling,conversion,straininga ndalcoholicfermentation.Warmwater(50°C)isusedformashing.Maltedsorghumisaddedtounmalted grainsintheratioof1:4.Waterandinoculumfromthepreviousbatchareadded.Souring(lacticacidferme ntation)takesplaceat48-50°Cfor8- 16hours.Lactobacillusischieflyresponsible.ThefinishedsourmashhasapHofabout3- 3.3.Themashisdilutedwith2volumesofwaterandboiledfor2hours.Itisthencooledto40- 60°Candadditionalmaltadded.Conversionproceedsfor2hoursandthenthemashiscooledto30°C.Afte rstrainingtoremovecoarsemalthusks,alcoholicfermentationbeginsusingtop- fermentingyeast(Saccharomycescerevisiae)asinoculum.Kaffirbeerisreadyin4- 8hoursatwhichtimeitisstillactivelyfermenting.Ithasashelf- lifeofupto40hours.AceticacidproductionbyAcetobacteristheprincipalcauseofspoilage.Thesestepsi nvolvedintheproductionofKaffirbeerareoutlinedinFigure3. Sorghum(kaffircorn,redvarieties) ↓ Cleanedandwashed ↓ Steepedfor8-24hours ↓ Germinatedfor5-7daysat25-30°Cindepthof3-4ftandwateredforfirst3days ↓ Grainsturnedandcoolairusedtoreduceheat ↓ Malt(60-65%moisture:rootsandshoots1-2inchesinlength) ↓ Driedat50-60°C ↓ Ground ↓ FinishedSorghummalt ↓ Warmwater+unmaltedcereal10%innoculumfrompreviousbatch ↓ Fermentation,48-50°C,8-16hours ↓ Finishedsourmash,Ph3-3.33 ↓ Pumpedtocookeranddilutedwith2volofwater 7 ↓ Intermittentadditionofcorngrits ↓ Cookedfor2hoursatatmosphericpressure ↓ Cookedto40-60°C ↓ Sorghummaltadded ↓ Heldfor2hours ↓ Cooledto30°Candtopfermentingyeast(Saccharomycescerevisiaeaddedaspureyeast) ↓ Strainedtoremovecoarseparticlesfomalthusks ↓ Fermentors30°C,8-24hours ↓ FinishedKaffirbeer Figure3.Kaffirbeerproduction BENEFITSOFALCOHOLICFERMENTATION Theprimarybenefitoffermentationistheconversionofsugarsandothercarbohydratestousableendprod ucts. 1. Beer,beingfermentedbeverage,containsdietaryfiberandcertainprobiotics,thesecomponentss upportguthealthbypromotingthegrowthofbeneficialbacteria.Abalancedgutmicrobiomeaids indigestionandstrengthenstheimmunesystem. 2. Fermentationeliminatestoxicsubstanceslikecyanide,proteaseinhibitors,hemagglutinins,rici n,tannins,phytates,flatuscausingoligosaccharidesetc.Thisisimportantinthecaseofcassava,s oyabeans,castorbeansandAfricanlocustbeanswhichareverytoxicintherawstatebutbecomen on- toxicandedibleafterfermentation.Understandablythesetoxiccompoundswhichalsoaffectdig estibilityaredestroyedduetothesoakingandcookingstepsaswellasthediscardingofthesoakorc ookwater. 3. Mostlocalfermentedbeersareinexpensiveandarethereforewithinthepurchasingpowerofman yindividualsinthecommunity.Productionoffermentedbeerbysmallscaleprocessorswillthere forecontributetotheeconomyofNigeriaandtotheimprovementinthenutritionofconsumers. 8