Chemistry Reference
In-Depth Information
table 8.3
Inhibitory Levels of Different Sweeteners on
Yogurt Starter Bacteria
Sweeteners
Level of Inhibitory effect (%)
Sucrose
>4.00
Fructose
>2.70
Aspartame
>0.02
Fructooligosaccharides
>7.30
Isomaltooligosaccharides
>7.70
Theincorporationofnutritivesweetenersotherthansucroseinyogurtproductionisratherlim-
ited. Fructose, which is derived mainly from the conversion of starch, may be an alternative to
sucrose to sweeten yogurt. A negligible effect of fructose on the lavor of yogurt after storage
wasreported(HyvonenandSlotte1983).Grapemustisanothersourceoffructose,andtheopti-
mum rate of use of grape must in the manufacture of fruit and lavored yogurt should be 20%
(Calvo,Ordonezi,andOlano1995).Fernandez-Garcia,McGregorandTraylor(1998)investigated
thechemicalandmicrobiologicalpropertiesofplainyogurtsupplementedwithoatiberandvari-
ousnaturalsweeteners(e.g.,sucrose,fructose).Additionoffructoseatalevelof5.5%causedan
increaseinthefermentationtimeby60%andsloweddowntheproductionoforganicacids,suchas
lactic,pyruvic,acetic,andpropionicacids.Apparentviscositiesoftheproductsincreasedwiththe
additionofsweetenersandoatibers.
Anundesirablebeanyaromaisthemajordrawbackofsoymilkyogurt(Favaroetal.2001).On
theotherside,thehighnutritionalvalueofsoyproductshasstimulatedeffortstoconvertsoyyogurt
into a more appealing product to consumers. Adding a sweetening agent, mainly sucrose, is one
oftheoptionstomaskundesirablelavorinsoyyogurt.Sucroseisnotutilizedby
Lb.delbrueckii
subsp.
bulgaricus
while
Str.thermophilus
iscapableoffermentingthissugar.Estevezetal.(2010)
investigatedtheroleofdifferentsugarcombinations(42%glucose+58%fructoseand42%glucose
+58%sucrose)ontheorganolepticacceptabilityofsoymilk-basedyogurt.Theyogurtfortiiedwith
aglucose-fructosecombinationreceivedthehighestsensoryscores.Theeffectsoftypes(sucrose,
fructose,andsucrose/fructoseat1:1)andconcentrations(6%,8%,and10%)ofsweetenersonthe
sensorypropertiesofsoy-fortiiedyogurtwerestudiedbyDrake,Gerard,andChen(2001).Withthe
increaseintheconcentrationofsweeteners,thesoylavorsandastringencydecreased.Thesweet-
enerconcentrationwasfoundtobemoreeffectiveonthesensoryqualityofsoy-fortiiedyogurtthan
thetypeofsweetener.
Anotheralternativenutritivesweetenerthatmaybeusedintheproductionofsweeteneddairy
productsisglucose-galactosesyrup(Thometetal.2005).Cornsyrup,whichisanotheralternative
sweetenertosucrose,istheproductinwhich20%-70%oftheglycosidelinkageshavebeenhydro-
lyzed(ChandanandO'Rell2006).Cornsyrup(with36or42DE)isgenerallyusedintheproduc-
tionoflow-fatandnonfatyogurtandfrozendesserts.Thefullreplacementofsucrosebycornsyrup
maycarrytheriskoflavordefects.Therefore,theuseofthissweeteningagentinfrozendesserts
is limited to 25%-30% of the total sweetener level. Corn syrup decreases the stiffness of frozen
yogurtwhileimprovingtheshelflifeoftheendproduct.Duringthelastdecade,HFCShasgaineda
relativepopularityintheyogurtandicecreamindustry.AccordingtoChandanandO'Rell(2006),
themostcommonblendsofsugarsandHFCSaremadeupina50:50mixbasedonsolids.HFCS
hadnonegativeeffectsonthequalityofyogurt,andtheacceptabilityoftheendproductincreased
(McGregorandWhite1986).Ontheotherhand,owingtoitshighOP,HFCSmayshowaninhibi-
toryeffectonyogurtstarterbacteria.
Othernutritivesweeteners,suchasmaltodextrin,crystallinefructose,andinvertedsugar,arefar
lesscommonlyemployedinthemanufactureofyogurt,buttheyaremostlypreferredforthemanu-
factureoflow-fatandnonfatfrozenyogurtorfrozendesserts.Thesesweetenersaremorewidely
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