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Principlesofmeatprocessingtechnology37Anotheracceleratingor“catalytic”effectistheadditionofascorbicacid,whichslightlylowersthepHofthemeatmixture.However,thedosageofascorbicacidmustbelow(0.05%),justtoprovidetheslightlyacidconditionsforthereductionofNaNO2toNO.ApronouncedreductionofthepHwouldnegativelyaffectthewaterbindingcapacityoftheproductwhichisnotdesirable.CuringofentiremeatpiecesBesidesthecuringofchoppedmeatmixtures,entirepiecesofmusclemeatcanbecured.However,duetosizethecuringsubstancescannotinstantlyreactwiththemeatpigmentsasisthecaseinchoppedmeatmixes.Hencevariouscuringtechniquesareapplied.Thefinalproductsofcuringentiremeatpiecesareeithercuredrawfermentedproductsorcuredcookedproducts(seepage98).Thecuringsystemtobeuseddependsonthenatureofthefinalproduct(uncookedorcooked).Therearetwosystemsforcuringentiremeatpieces,drycuringandwetcuring(“pickling”)andthetypeofthefinalproductdetermineswhichsystemwillused.Indrycuringacuringmixispreparedcontainingsaltornitritecuringsalt,togetherwithspicesandotheradditives.Thepiecesofmeatarerubbedwiththiscuringmix(Fig.63,64,214,215)andpackedintanks.Thecuringmixgraduallypermeatesintothemeat,whichcanbealengthyprocessrangingfromseveraldaystoseveralweeks.Formoredetailsseepage173).Drycuringisexclusivelyusedforthefabricationofcuredrawfermentedproducts,inparticularthosewithalongripeningperiod.Fig.62:Addingofnitritecuringsaltduringinitialphaseofmeatmixfabrication38PrinciplesofmeatprocessingtechnologyThesecondmethodofcuringmeatpiecesiswetcuring,alsocalledpickling,whichinvolvestheapplicationofcuringbrinetothemeat.Forthemanufactureofthebrine,curingsaltandspices,andotheradditivesifrequiredaredissolvedinwater(seepage179).Themeatcutsarepackedintanksandbrineisaddeduntilallpiecesarecompletelycovered(Fig.65).Atemperatureof+8to+10oCforthecuringroomisrecommendedaslowertemperaturesmayretardcuring.Forequalpenetrationofthebrine,themeatiscuredforperiodsrangingfromseveraldaystotwoweeksdependingonthesizeofthecutsandcuringconditions.Aftercompletionofthecuring,ripeningperiodsfortheproductsfollowfortasteandflavourbuild-up(formoredetailsseepage175).Wetcuringbyimmersionofmeatpiecesinbrineisprimarilyusedforthefabricationofcuredrawfermentedproductswithshorterripeningperiods.Fig.64:HamisuniformlycoveredbycuringmixFig.63:Applicationofdrycuringmix(curingsalt,curingaccelerators,spices)onfreshham(porkleg)Fig.65:WetcuringPrinciplesofmeatprocessingtechnology39Analternativeandquickwayofwetcuringistoacceleratethediffusionofthecuringsubstancesbypumpingbrineintothemeattissue(“injectioncuring”).Forthispurposebrineinjectorswithperforatedhollowneedlesareused.Theinjectionofbrineintothemusclescanbedonemanuallybyusingsimplepumpingdevices(Fig.43,44,66,67).Attheindustriallevelsemi-automaticmulti-needlebrineinjectors(Fig.45,46,68)areusedwhichachieveveryevendistributionofthecuringingredientsandcanreducethecuringperiod(equaldistributionofthecuringsubstancesor“‘restingperiod”)tolessthan48hours.Fig.66:ManualbrineinjectionusingalargesyringeFig.67:BrineinjectionwithamanualcuringpumpFig.68:Multi-needlebrineinjection(principle)40PrinciplesofmeatprocessingtechnologyInaddition,mostinjectioncuredmeatpieceswhicharetobeprocessedintocured-cookedproducts(suchascookedhamsetc),aresubmittedtoatumblingprocess(seepage28,184).Tumblingfurtheracceleratesthebrinepenetrationthroughoutthemeatpricesand“restingperiods”arenotnecessary.3.SmokingSmokefortreatmentofmeatproductsisproducedfromrawwood.Smokeisgeneratedthroughthethermaldestructionofthewoodcomponentsligninandcellulose.Thethermaldestructionsetsfreemorethan1000desirableorundesirablefirm,liquidorgaseouscomponentsofwood.Theseusefulcomponentscontributetothedevelopmentofthefollowingdesirableeffectsonprocessedmeatproducts:¾Meatpreservationthroughaldehydes,phenolsandacids(anti-microbialeffect)¾Antioxidantimpactthroughphenolsandaldehydes(retardingfatoxidation)¾Smokeflavourthroughphenols,carbonylsandothers(smokingtaste)¾Smokecolourformationthroughcarbonylsandaldehydes(attractivecolour)¾Surfacehardeningofsausages/casingsthroughaldehydes(inparticularformorerigidstructureofthecasing)Themostknownundesirableeffectofsmokingistheriskofresiduesofbenzopyreneinsmokedproductswhichcanbecarcinogeniciftheintakeisinhighdosesoverlongperiods.Withnormaleatinghabits,acarcinogenicriskisnormallynotassociatedwithmoderatelysmokedfoodsuchassmokedmeatproducts.Dependingontheproduct,smokeisappliedatdifferenttemperatures.Therearetwoprincipalsmokingtechniques:¾Coldsmoking¾HotsmokingTheprincipleofbothmethodsisthatthesmokeinfiltratestheoutsidelayersoftheproductinordertodevelopflavour,colourandacertainpreservationeffect.Wetcuringbybrineinjectionisusedforthefabricationofcuredcookedproducts(seepage177).Principlesofmeatprocessingtechnology41ColdSmoking–Thisisthetraditionalwayofsmokingofmeatproductsandwasprimarilyusedformeatpreservation.Nowadaysitservesmoreforflavourandcolourformation,forexampleinsausagesmadefromprecookedmaterialssuchasliversausageandbloodsausage(seepage153,161).Thecombinationofcoldsmokinganddrying/ripeningcanbeappliedtoferm