oil and fat technology lectures ii.ppt

oilandfattechnologylecturesii handling storageofoil bearingmaterials pretreatments prof dr ayta sayging m kesenyrd do dr fahriyem o lu handling storageofoil bearingmaterials thehandlingandstorageofoil bearingmaterialsisoneofthemostimportantphasesofoilseedprocessing thevegetableoilsandfeedindustriesaredependentforsuccessfuloperationuponobtaininghighyieldsandproductofgoodqualityfromtheirrawmaterial excessivebiologicalactivityintheseeds eitherinthefieldpriortoharvestingorsubsequentlyduringstorage willresultinareductionbothinthequalityandtheyieldofoilandmeal thehandlingandcontroloftherawmaterialsfortheoilseedindustrycanbeprimarilycharacterizedbytheshortharvestseason bythenecessitytomovethemintoprotectedstorageinminimumtime andbytherequiredcarebeforetheycanbeprocessed buttheycanbetreatedandstoredsuccessfullywithminimaldeteriorationlongenoughtoallowtheprocessingindustrytooperatethroughouttheyear sunflowerseed soybeans cottonseed rapeseedandotheroilseedsaresubjecttodamageprimarilyfrombiologicalactions whichareacceleratedbyhighmoisturecontent foreignmaterial physicaldamage andsuchadverseclimaticconditionsasfrostorrainbeforeharvest effectsaccompanyingdeteriorationofseedduringstoragerespiration inthepresenceofoxygenastheoxidizingagent organicfoodstuffsareoxidizedtoformwaterandcarbondioxideastheendproduct exothermicreactionc6h12o6 o26co2 6h2o energyrespirationintensity soundseed lowm c 0 1mlco2 gseed daydamagedseed highm c 5 0mlco2 gseed day therespiratoryquotient definedastheratioofcarbondioxideevolvedtooxygenabsorbed isanindicationoftheclassofsubstancesundergoingoxidation inaerobicrespiration itistheoreticallyunityifthesubctancesarecarbonhydrates butlessthanunityiftheyareproteinsorfats whicharelessrichinoxygen enzymes a lipase thisenzymecatalyzesthereaction 1glycerol 3fattyacidtriglycerid 3water21synthesist g2hydrolysist g b catalaseandperoxidase bothoftheseenzymesreactwithhydrogenperoxide catalasewilldecomposehydrogenperoxidewhileperoxidaseutilizesitforfurtheroxidation 2hydrogenperoxide2water oxygen influenceofmoisturecontent oilseedsarebeststoredatlowmoistureswhererespirotaryandenzymicactivities germinationandmoldgrowthareinhibited thismaximumacceptablemoisturelevelisknownas criticalmoisturelevel cml themoisturecontentofthenonoilportionoftheseedratherthanthewholeseedistheimportantfactorinoilseeddeterioration cmlisrelativelyhighforseedsoflowoilcontent cmlisrelativelylowforseedsofhighoilcontent safehumidityforstarchyfoodgrains16 oilcontentofsoybean 22 non oilypartofsoybean 78 criticalmoisturelevel0 78x16 12 5 cmlofoilseedshulls fat cml rapeseed14407 0palmkernel 528 0sunflowerseed28438 5cottonseed481810 0soyabeans82012 0 influenceoftemperature inthecaseofsoyabeansandsimilaroilseedswheredeteriorationappearstobprimarilyaresultofthegrowthofmicroflora thestoragetemperaturedoesnotappeartobeamajorfactor however temperatureisveryimportantfactorinstorageofcottonseed therespirationofcottonseedismarkedlytemperature dependent theinsulatingeffectoflintersoncottonseedcontributestothepeculiartendencyofthisseedtoheatinstorage itisbecauseoftheundesirableeffectofhightemperaturethatmostseedhousesareequippedwithaerationductsandlargeventilatingblowerstocooltheseed storagemethodwarehouses muskogeetypeseedhouses bulkstorageinwarehousesonflatfloorshastheadvantageofeasycontrolofoilseeds likecottonseeds sunflowerseed corngerm furthermealsetc topreventselfheatingorautocombustionoftheseeds recyclingbyhorizantalandverticaltransportationmeansisrecomended muskogeetypeseedstore beltconveyer sectionthroughstoragebuilding oilseed oilseedbulk preparationofoil bearingmaterialscleaningforeignmaterialsdelintingforcottonseedlintsdehullinghullsflakingcookingmoist cleaningcleaningisimportantnotonlytoensurethegoodqualityofthefinalproductsoilandmealbutalsotoavoidprematurewearofthepreparationequipment theremovalofforeignmaterialsfromoilseedsisdonebycleaningmachinesworkingonmechanical pneumaticandmagneticprinciples cleaningmachines screensaspiratorsmagnetsshapesorters screensscreeningistheseperationofmixturesofdifferentsizesintofractions theportionstayingbehindbeingoversize theportionpassingthroughbeingundersize rotatingscreensvibratingscreens drumscreen vibratingscreen aspiratorsinordertoseperateimpuritiesorfractionsofdifferentdensity pneumaticmeans likeairnozzlesandaspiratorsareused magnetspermenantorelectromagnetsenclosedinarotatingaluminiumdrumareusedinfeederstodistributethematerialuniformlyoverthewholeactivewidthofthedrum themagneticmaterialcollectedisremovedbyabladeontheono magnetizedhalfand inthisway itremainsseperatedeveninthecaseofpowerfailure selfcleaningrotarymagnets seedinlet aspirator rotatingdrum stationarymagnet ronparts cleanedseed delinting forcottonseed cottonseed lints 8 12 hull 40 45 delintingprocesstoremovetheremaininglintfromcottonseedaimsofdelinting 1 increaseoilyield2 obtainfirst andsecond cutlinters delinter cuttingoperation cottonseed saws brush delintedseed cutlints seedfeeder sawteeth methodofdelintingcottonseedcomprisesthestepsofpassingthecottonseedthroughasawdelintertoremoveasubstantialportionofthelint preferablyatleast40 andthereafterpassingthepartiallydelintedseedthroughabrushdelintertoremovesubstantiallyalloftheremaininglint cottonseeddelintingequipment dehulling dehullingisaprocessofremovinghullsfromtheoilseedsforobtaininghighqualityedibleoilbytheprocessingofkernels thisreducesfibrouscontentofthemealandincreasesthemarketabilityasstockfeed about99 ofoilisstorednaturallyinkernelsandthehullscontainnotmorethan1 oil ifthehullsarenotremovedtheyreducethetotalyieldofoilbyabsorbingorretainingoilinthepressedcake inadditiontothisthewaxandcolouringmatterspresentinthehullsgetmixedwiththeexpressededibleoil thisnecessitatedtherefiningprocess andtherefore increasetheproductioncostofedibleoil moreover processingoilseedswithoutdehullingreducesthecapacityoftheextractionequipmentinadditiontomorerepairandmaintenancecharges approximatehullsandkernelspercentageindifferentseeds oil kernel hullwholekernelhuskcottonseed554519301 2rapeseed821842 sunflower752522 3636 551 2soybean93718190 6 hullerthehullingmachinesusedforthedecorticationofmedium sizedoilseedswithaflexibleseedcoat suchascottonseed sunflowerseedandpeanuts areoftwoprincipletypes barhullersdischullers barhuller therotatingmemberofabarhullerisacylinderequippedonitsoutersurfacewithanumberofslightlyprojecting longitudinallyplaced sharplyground square edgedknivesorbars opposedtothecylinderoveranareacorrespondingtoaboutone thirdofitssurfaceisaconcavememberprovidedwithsimilarprojectingbars theseedarefedbetweentherotatingcylinderandtheconcavemember andthehullsaresiplittedastheseedsarecaughtbetweentheopposedcuttingedges theclearencebetweenthecuttingedgesmaybeadjustedforseedofdifferentsizes seed bars concavesurface1 3 square edgedknives dischuller thedischullerconsistsofverticallymounteddiscs oneofwhichisstationaryandtheotherrotating theseedsarefedtothecenterofthediscsandaredischargedattheirperipherybycentrifigalforce seeds rotatingdisc stationarydisc adjustaccordingtoseedsize themoisturecontentofseedeffectstheefficiencyofdehullingoperation wetseedsaredifficulttosplitcleanlyandmayclogthehuller iftheseedsareverydry thekernelsmaydisintegrateexcessively universaldehullingseedfirsthuller coarshuller hullbeaterkernelhulluncutseedsecondhullerhullbeaterkernelhulluncutseed flakingtheextractionofoilfromoilseeds eitherbymechanicalextractionorsolventextraction isfacilitatedbyreductionoftheseedtosmallparticles flakingisachievedoncorrugatedrollstands crackingmillswithoneortwopairsofrollsareused hammermillsareusedforcertainrawmaterialslikepalmkernel crushingrollsarollassemblycommonlyusedforthereductionofoilseedsconsistsofaseriesoffiverollsplacedoneabovetheother theseedisintroducedbyafeedingmechanismbetweenthetwotoprolls seedtravelsfromthetoptothebottomofthesystem henceitisrolledfourtimes corrugatedrollspeed0 05m secknifesmoothrolls kernel flake crushingrolls cooking heattreatmenteffectsofcookingprocessonthephysicalandchemicalpropertiesofoilseeds theoildropletsintheoilseedareultramicroscopicinsize becauseoftheincreaseintemperaturetheycometogetherandformlargerdropletstoflowfromtheseed heatingoftheseedscausestheproteintodenatureandasaconsequence theemulsiontobreakandtheoiltoseperatefromthesolidsurfaceoftheseed cookingoftheseedgivestheseedmasstheproperplasticityforefficientpressing insolubulizationofphosphatidesandotherimpurities destructionofmoldsa