Chemistry Reference
In-Depth Information
4.9 NeOtaMe
Neotameisanewhigh-potencynonnutritivesweetenerthatisconsideredasthepotentialsuc-
cessorofASP.AsaclosederivativeofASP,ithastheintrinsicqualitiesofthiscompound,which
wereattherootoftheASPcommercialsuccess,notablyaverycleansweettaste,closetosucrose,
with no undesirable bitter or metallic taste that occur in other well-known artiicial sweeteners.
Moreover,NTMoffersadditionalsalientadvantagessuchasthefollowing:astatus,atuselevels,of
ano-caloriesweetener;anincreaseinstabilityintheneutralpHrange,whichstronglyimprovesor
widenstheASPapplications(e.g.,inbakedgoods);chemicalinertnesstowardreducingsugarsand
aldehydicderivativesallowingitsassociationwithreducingsugars(glucose,fructose,high-fructose
corn syrup, maltose, lactose, etc.) and lavoring agents based on aldehydic constituents (vanillin,
ethylvanillin,cinnamaldehyde,benzaldehyde,citral,etc.);aninsigniicantreleaseofmethanoland
phenylalanineintotheorganismafterintake(with,inparticular,nopossiblehazardforphenylke-
tonuricsubjects);andaforeseeablehighlycompetitiverelativecost(costpersucroseequivalent)as
aresultofitshighsweetnesspotency.
NTMisaderivativeofthedipeptidecomposedoftheaminoacidsasparticacidandphenylala-
nine(Figure4.7).TheoptimumpHformaximumstabilityis~4.5.NTMhasbeenapprovedinthe
UnitedStates,Australia,andNewZealand.
NTMisthegenericnameforN-[N-(3,3-dimethylbutyl)-l±a-aspartyl]-l-phenylalanine1-methyl
ester. Its structural formula is given in Figure 4.7; its molecular formula is C
20
H
30
N
2
O
5
, and its
molecularweightis378.47.NTM'ssolubilityis740timesgreaterthannecessarytoobtainasweet-
nesslevelmatchinga10%sucrosesolution(17g/LofNTM).
NTMisconvenientlypreparedfromASPand3,3-dimethylbutyraldehyde;inaone-stephigh-
yieldprocess,NTMisanodorlesswhitecrystallinecompound,whichmaybeobtainedanhydrous
or,moreusually,asahydrate(4.5%hydrationwater;empiricalformulaC
20
H
30
N
2
O
5
.H
2
O;formula
weight396.48).ThemeltingpointoftheNTMhydrateis80.9°C±83.4°C(withoutdecomposition
ofthemoleculebelow200°C).
ThecrystalstructureofNTMwasobtainedfromsinglecrystalX-raydiffractionanalysis;the
twohydrophobicgroupsoftheNTMmoleculearesuperposedinthecrystalinaU-shapedconfor-
mation. NTM is stable under dry storage conditions; in dry conditions, its estimated shelf life is
severalyearsatambienttemperature.Themonohydratedformisnothygroscopic.
ThesolubilityinwaterofNTMis12.6g/L(10g/Lforairbornparticulatematter [APM]) at
25°C.ItsMRSis10%(i.e.,themultipleoftherequiredsolubilitytomatchthesweetnessintensity
of NTM is an amphoteric compound). At 25°C, its pK
1
is 3.01, and its pK
2
is 8.02 (3.1 and 7.9,
respectively,forAPM).ThepHofitsisoelectricpoint(minimalchargeand,ingeneral,minimal
solubility)is5.5(closetothatofAPM).NTM,atuselevels,hasnegligibleeffectsonviscosity.Its
insigniicantviscosityshouldnotgiverisetoanymixingproblems,andthenegligibleloweringof
CH
3
H
3
C
H
3
C
O
NH
O
NH
CH
3
HO
O
O
Figure 4.7
Chemical structure of NTM.
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