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Happy Days Dairies Ltd. Article # 7 - Properties and Benefits of Fermented Dairy Products By Sarah Holvick, B.Sc. Nutrition Released March 17, 2014 Happy Days Dairy Ltd. 691 Salmon River Road Salmon Arm, BC V1E 3E9 250-832- 0209 [email protected] www.happydaysdairy.com Table of Contents Introduction................................................................................................................... 3 Fermentation and End Products................................................................................... 3 The Biochemical Process of Fermentation .................................................................. 4 Yogurt .......................................................................................................................... 5 Cheese ..........................................….......................................................................... 6 Kefir …......................................................................................................................... 6 Technological Difficulties or Producing Fermented Goat Milk Products....................... 6 Health Benefits of Fermentation…............................................................................... 6 Hypotensive Peptides ….............................................................................................. 7 Antimicrobial Activity …................................................................................................ 7 Gastrointestinal and Urogenital Health ........................................................................ 7 Antioxidative and Anticarcinogenic Effects ................................................................. 8 Allergy Management …............................................................................................... 8 Conclusion ................................................................................................................... 9 References ................................................................................................................ 10 Article#7-PropertiesandHealthBene itsofFermentedDairyProducts By:SarahHolvik,B.Sc.Nutrition Goatmilkisanutritionalandtherapeuticfood.Theuniqueandbene icial characteristicsofthisdairyalternativethataresuperiortocowmilkhavebeen previouslydiscussed,andinclude:betterdigestibility,greaterbufferingcapacity,fat globulesthataresmallerindiameterandbetterdistributedinthemilkemulsion, highercontentofshort-chainfattyacidsinthemilkfat,highercontentofzinc,iron andmagnesium,strongerlactoperoxidase(antimicrobial)systemaswellasbetter immunologicalandantibacterialproperties.Thegreateramountsofcertain mineralssuchascalcium,zincandmagnesiumingoatmilkmayalsoin luenceand facilitatethegrowthoflacticacidbacteriaastheyareanormalpartofsome enzymaticcomplexesinvolvedinthefermentationoflactose.Furthermore,the higherwheyproteincontentcouldalsobesigni icantbecauseLactobacillus acidophilusandBi idobacteriagrowmorereadilyinthepresenceofhigherlevelsof someaminoacids.Fermentationisknowntoamplifytheexistingbene icial propertiesofdairyproducts,andfermentedgoatmilkalternativeshavebeenshown tohavegreathealthadvantages,includinganti-allergenic,probioticandanticarcinogenic.Ithasalsobeenshownthatnutritivevalueofgoatmilkincreases duringfermentationandthatitlosesitscharacteristic“goaty”taste,whichis unacceptabletomanyconsumers(Slancanacetal.,2010). Fermentation&EndProducts Foodspoilagecausedbymicroorganismswasanimportantproblemthroughout humanhistory.Findingwaystoovercomethisissuebecameincreasinglynecessary ascommunitiesexpandedandnoteveryoneproducedtheirownfood.Asaresult, preservationmethodssuchassalting,drying,canningandpasteurizationwere developedinordertodelayfoodspoilage.Fermentationwasalsodiscoveredearly ontobeagoodmethodforpreservationbyusingthegrowthofcertain microorganismsinfoodasanadvantage.Thefermentationprocesshasbeenshown toincreasethenutritivevalueofdairyproducts.Table1showstheincreasein variouscomponentsincowandgoatmilks,demonstratingthatthelattercontains higheramountsofbene icialorganicacidsbothbeforeandafterfermentation. 3 Table1.Organicacidproductionduringfermentationofgoatandcowmilks (Slacanacetal.,2005) TheBiochemicalProcessofFermentation Fermentationreferstothemetabolicprocessbywhichmicrobesproduceenergyin theabsenceofoxygenandotherterminalelectronacceptorsintheelectron transportchain.Allorganismsneedenergytogrow,anditisknownthatthisenergy comesfromthereductionofadenosinetriphosphate(ATP)toandenosine diphosphate(ADP),resultinginthereleaseofenergyandaphosphategroup.Cells obtainATPfromthechemicalbreakdownofglucosetoformtwomoleculesof pyruvate,alsoknownasglycolysis(Figure1).AlthoughthisprocessrequiresATP,it resultsinareleaseoffourmoleculesforanetgainoftwoATPmolecules.Once pyruvateisformed,itcanbeprocessedaerobically(inthecaseofmammaliancells), oranaerobically(inthecaseoffermentation).Twoofthemostimportant fermentationprocessesthatareusedonanindustrialscaleareethanolorlacticacid fermentation(Figure1). 4 Figure1.Glycolysisandfermentation (Yim&Glover,2003) Yogurt Yogurtisproducedthroughthefermentationofmilkbylacticacidbacteria,usually lactobacillusbulgariusandStreptococcusthermophilus.Milkisusually irstheated, homogenizedandisthencooledinorderforthestartercultureorbacteriatobe added.Thebacteriathenusethelactoseinmilkasafoodsourceforthe fermentationprocess,generatinglacticacidasaresult.LacticacidlowersthepHof theyogurttherebyactingasapreservativesincemostpathogenicbacteriacannot growinacidicconditions,makesittart,andcausesthemilkproteinstocoagulate andset,formingyogurt. 5 Cheese Cheeseisfermentedmilk,whichhasaportionofitswaterandlactoseremoved. Thereare4basicstepstomakingcheese:curdling,draining,pressingandripening. Curdlingiswhentheliquids(whey)areseparatedfromthesolids(curds)bythe additionofafermentingagent.Cheesethenundergoesdraining,wherethewheyis eliminatedfromthecurd.Thisstepisimportanttoattainthecorrectmoisture contentinthecheese.Pressingoccursnext,inordertoeliminatemorewhey.Finally, thecheeseisripenedandtakesonitsuniquecharacteristicsof lavour,textureand aroma. Ke ir Traditionally,thefermentationofke irwasdoneathomeasamechanismto preservemilkbeforetheadventofrefrigeration.Nowadays,thecommercial productionofke irstartswiththepasteurizationofmilkinordertokillbacteriathat cancauseunwantedspoilageoftheendproduct,whichisheat-treatedinorderto denaturethewheyproteins.Theproductisthencooled,andke irgrainsorculture areadded.Theke ircultureisknownas“grains”becauseitformsgrain-likecasein polysaccharide-microorganismparticlesduringfermentation.Oncetheculturehas beenadded,themixtureisincubatedfor24hoursbeforetheyareremovedandthe productispasteurized,chilledandpackaged. TechnologicalDif icultiesofProducingFermentedGoatMilkProducts IntheEuropeanUnion,goatmilkproductsareconsideredtobethedairyproduct withthegreatestmarketingpotentialand,therefore,severalcharacteristicsofgoat milkarecurrentlythefocusofincreasedresearchinterest.However,alongsidethe nutritionalandtherapeuticadvantagesofgoatmilkanditsfermentedproductsin particular,therearealsosometechnologicaldif icultiesassociatedwiththe productionoffermentedgoatmilkwithgoodsensoryproperties.Themajorityof theseissuesareassociatedwiththespeci iccompositionandstructureofgoatmilk. Asgoatmilkhasaslightlylowercaseincontentthancow'smilk,withaverylow,or sometimesevenabsentamountofαS1-casein,andahigherdegreeofcaseinmicelle dispersion,theconsistencyoffermentedgoatmilkproductshasbeendeterminedto beoneofthecriticalproblems.Inaddition,seasonalchangesinthecompositionof goatmilkalsoin luencetheconsistencyoffermentedproducts.Thesefactors in luencethecurd-formingpropertiesinfermentedgoatmilk,whichismuchweaker thanthatofcowmilk.Furthermore,anotherproblemisover-acidi icationof fermentedgoatmilkproductsincomparisonwiththoseofcowmilk(Slancanacet al.,2010). HealthBene itsofFermentation Wehavediscussedthebene icialpropertiesofgoatmilk,makingthisdairyproduct superiorintermsofhealthbene itsincomparisontocow'smilk.Theadditional bene itsoffermenteddairyproductsarealsoknown,thereforeitmaybesaidthat fermentedgoatdairyproductsexertgreaterhealthadvantages. 6 Hypotensivepeptides Thefermentationoftheproteinsinmilkbylactic-acidbacteriamayresultinthe releaseoftripeptideswithbloodpressureloweringactivities.Twoofthesepeptides, isoleucylprolyl-proline(Ile-Pro-Pro)andValyl-Prolyl-Proline(Val-Pro-Pro)have beenisolatedconsistentlyfromcaseindigestsandhavebeenshowntolowerblood pressureinspontaneouslyhypertensiveratsandinhumanswithmildhypertension. Inanotherstudy,middle-agedsubjectswithmoderatehypertension(systolic readingsbetween140and180mmHganddiastolicreadingsbetween90and110 mmHg)received150mlofamilkfermentedwithL.helveticusLBK-16H,twicedaily for16weeks,with7.5mg/100gofIle-Pro-Proand10mg/100gofVal-Pro-Pro.The controlgroupreceivedthesameproductastheexperimentalgroupbutwithoutthe twoactivepeptides.Bloodpressurewasmonitoredatthebeginningandattheend ofthetrialwithanautomatic,24-hourpressurerecorderand,inadditionevery participantwassubjectedtoninebloodpressurecontrolsatregularpredetermined intervals.Theresultsshowedthattherewasadifferenceof0.9mmHginthesystolic pressureanda-1.8mmHgbetweentheL.helveticusandthecontrolgroups, respectively.Thiskindofareductioninbloodpressureisconsidered epidemiologicallysigni icantintermsofpublichealth. Furthermore,invivoandinvitroACE-inhibitoryactivityoriginatingfromthe fractionationofcaseinshasbeendetectedinmilkproductsusingdifferentbacterial strainsduringfermentation.ACEisoneofthemainbloodpressure-regulating moleculesasitisabletosynthesizeangiotensinII,apotentvasoconstrictor. Furthermore,thisprocessofangiotensinIIsynthesisinducesbradykinin degradation,whichisapowerfulvasodilator.Therefore,theoveralleffectof inhibitingACEresultsinaloweringofbloodpressure.Astudyongoat'smilkke ir detectedthepresenceofACE-inhibitorypeptidesthatshowedanti-hypertensive activity,twoofwhichwereparticularlypotent.Thedigestionwithgastricand pancreaticenzymesfurtherhydrolyzedtheoriginalpeptidesandsomeofthe resultingproductsalsoexhibitedvasomotoreffects(Brunseretal.,2007). Antimicrobialactivity Aswehavementionedinapreviousarticle,manybioactivepolypeptideshavebeen identi iedinencryptedforminmilkproteins,whicharereleasedduring fermentationand/orduringdigestionoftheseproteinsbythegastricandpancreatic enzymesinthegastrointestinaltract.Thesepeptidesincludefamiliesorsingle peptidescalledcaseicidins,isracidins,andlactoferrin,whichhavetheabilitytolyse pathogenicbacteriaincludingStreptococcusmutans,E.coliO157:H7and Enterobacterzakazakii.Thelaterhasbeenrecognizedastheetiologicalagentofa formofneonatalmeningitis(Brunseretal.,2007). Gastrointestinalandurogenitalhealth Therehavebeennumerousstudiesconductedinordertodeterminetheeffectsof fermentedgoatmilkontheinhibitionofvariousintestinalandurogenitalpathogens. 7 Forexample,Slacanacetal(2004)investigatedtheeffectsoffermentedmilkon urogenitalpathogeninhibitionandfoundaconsiderablyhigherinhibitoryeffectof goatmilkfermentedwithB.longumonthegrowthofC.albicanscomparedwiththat offermentedcowmilk.Similarly,Pavlovicetal.(2006)analysedtheantagonistic actionofgoatandcowmilkfermentedwithB.longumBb-46onthepathogenic organismsSerratiamarscensesandCampylobacterjejuni.Theirresultsalsoshoweda greaterinhibitoryeffectoffermentedgoatmilk. AChileanstudyinvestigatedtheeffectsofamilkformulaacidi iedbytheadditionof L.helveticusandS.thermophileson82weanedinfantslessthan12monthsofagefor a6-monthperiod.Inaddition,agroupof104infants,comparableintermsofthe anthropometricandsocio-economicpointsofview,andwhoreceivedtheirmedical careinanearbyareaservedascontrolsandreceivedanon-fermentedmilkof similarcomposition.Thefermentedmilkdemonstratedaclearpreventiveeffect againstnewepisodesofdiarrhea,astheincidence,durationandfrequencyof recurrenceweresigni icantlylowerinthisgroup.Similarly,variousspeciesand strainoflacticacidbacteriahavebeenevaluatedfortheirabilitytomodifythe courseofviraldiarrhea,andL.rhamnosusGG(LGG)hasbeenthemostextensively tested,especiallyforitseffectsondiarrheaassociatedwithrotavirusinfectionin children.Whenadministeredinassociationwithfermentedmilk,asigni icant shorteningoftheevolutionofthediseasewasobservedincomparisontothecontrol group(Brunseretal.,2007). Antioxidativeandanticarcinogeniceffects Kullisaaretal.(2003)studiedtheantioxidativeeffectsofafermentedgoat'smilk. Theyassignedtwenty-onehealthysubjectstotwotreatmentgroups:goat'smilk groupandfermentedgoat'smilkgroup(150g/d)fortwenty-onedays.Consumption ofthefermentedgoat'smilkimprovedanti-atherogenicityinhealthysubjects, prolongedresistanceofthelipoproteinfractiontooxidation,loweredlevelsof peroxidizedlipoproteins,oxidizedLDL,andglutathioneratio,andenhancedtotal antioxidativeactivity.Furthermore,thesubjectsreceivingthefermentedgoat'smilk groupshowedanalteredprevalenceandproportionoflacticacidbacteriaspeciesin thegutmicro lora. Animalfoodproducts,particularlydairyproducts,arerichinconjugatedlinoleic acid(CLA).CLAisknowntopossessanti-carcinogenic,atherosclerosisinhibiting andbodyfatreducingproperties,andhenceitsconsumptionisconsideredtohave healthbene itingeffects.Indratiningsihetal.(2012)investigatedtheeffectof fermentationonchangesintheCLAcontentingoatmilk.Theresultsdemonstrated thatthefermentationprocessincreasedtheCLAcontentofgoatmilkfrom3.09 mg/gfatinfreshmilkto3.26mg/gfatinfermentedmilk. Allergymanagement Anumberofstudieshaveshowntherelationshipbetweenallergicconditionsand thecompositionofthegutmicrobiota.Thelevelsofbi idobacteriainstoolsfrom 8 allergicinfants,particularlythosewithatopiceczema,aresigni icantlylowerthan thoseinhealthysubjects.Therefore,ithasbeenproposedthattheintakeof fermentedproductscontaininglacticacidbacteriacouldbeusedtoachieve homeostasisofthegutmicrobiotaandtherebydecreasethesymptomatologyin infantsatriskforallergy(Brunseretal.,2007;Gilliland,1999). Conclusion Fermenteddairyproductshavealonghistoryofbeingimportantdietary componentsforhumans,andthemorerecentapplicationofmodernresearch methodologiesisshowingthatthebacteriaandtheproductsofthefermentation processparticipateinavarietyoffunctionsthatarepositiveforhealthandwellness ofallagegroups. References: Brunser,O.,Gotteland,M.,Cruchet,S.Functionalfermentedmilkproducts.Nestle NutritionWorkshopPediatricProgram.2007;60:235-247. Gilliland,S.E.Technological&CommercialApplicationsofLacticAcidBacteria; Health&NutritionalBene itsinDairyProducts.Availableat: ftp://ftp.fao.org/es/esn/food/Gilli.pdf Howcheeseismade.Availableat:http://www.dairygoodness.ca/ Indratiningsih,S.,Djojowidagdo,Z.,Bachruddin,Z.,Widyobroto,B.P.Conjugated st LinoleicAcid(CLA)ContentinFermentedGoatMilk.1 AsiaDairyGoatConference. 2012;9-12. Kullisaar,T.,Songisepp,E.,Mikelsaar,M.,Zilmer,K.,Vihalemm,T.,Zilmer,M. Antioxidativeprobioticfermentedgoats'milkdecreasesoxidativestress-mediated atherogenicityinhumansubjects.BritishJournalofNutrition.2003;90:449-456. Nummer,B.A.FermentedFoods:Ke ir.Availableat: http://nchfp.uga.edu/publications/nchfp/factsheets/ke ir.html Slacanac,V.,Bozanic,R.,Hardi,J.,Szabo,J.R.,Lucan,M.,Krstanovic,V.Nutritionaland therapeuticvalueoffermentedgoatmilk.InternationalJournalofDairyTechnology. 2010;63:1-19. Slacanac.V.,Hardi.J.,Pavlovic.H,,Vukovic,D.,Cutic.V.Inhibitoryeffectofgoatandcow milkfermentedbyABT-2culture(LactobacillusacidophilusLa-5,Bi ido-bacterium lactisBb-12andStreptococcusthermophilus)onthegrowthofsomeuropathogenic E.colistrains.ItalianJournalofFoodScience.2004;16:209–219. Yim,G.,Glover,C.Foodmicrobiology:thebasicsandthedetailsofcheeseproduction. TheScienceCreativeQuarterly.2003;8:1-3. 9