Chemistry Reference
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O
O
-
Na
+
S
NH
O
Figure 4.4
Chemical structure of sodium cyclamate.
duetoitspossiblecarcinogeniceffects.OwingtoastudybyWagner(1970)whofoundanincreased
incidenceofbladdercarcinomasinrats,theuseofcyclamatewasprohibitedintheUnitedStates
andtheUnitedKingdom.However,furtherevaluationsbytheCancerAssessmentCommitteeofthe
CentreforFoodSafetyandAppliedNutritionoftheFDA,bytheSCFoftheEuropeanUnion,and
bytheWorldHealthOrganization(WHO)concludedthatcyclamateisnotacarcinogen(Takayama
etal.2000).Nowadays,cyclamateisapprovedforuseinmorethan50countriesworldwide.The
ADIvalueforcyclamatehasbeensetat11mg/kgbodyweightbytheJECFAandat7mg/kgbody
weightbytheSCF(Armentaetal.2004a,b).Becausethesafetyofcyclamatetohumansisnotclear
completely,therestrictedcontentlevelinfoodsisdifferentindifferentcountries(Wagner1970).
Cyclamate(Figure4.4)isgenerallyusedintheformofasodiumsaltbecauseitismoresolublein
waterthanthefreeacid.Thecalciumsaltisalsousedasasweetener,but,forsomeapplications,it
isnotsuitableasitcancausegelationandprecipitation.Sodiumcyclamateexhibitsgoodstability
inthesolidformandisalsostableinsoftdrinkformulationswithinthepHrange2-10.Cyclamate
ispermittedinseveralcountries(EU,Australia,Canada,NewZealand,etc.).However,ithasbeen
bannedintheUnitedStatesaftercontroversialtoxicitystudies.
4.7 GLYCYrrhIZIN
Glycyrrhizinisfoundinthelicoricerootofasmallleguminousshrub,
Glycyrrhiza glabra
L.,
from Europe and Central Asia. Glycyrrhizin or 20-β-carboxy-11-oxo-30-norolean-12-en-3β-yl-2-
O
-β-d-glucopyranurosyl-α-d-glucopyranosiduronicacid(C
42
H
62
O
16
,MW822.92)isatriterpenoide
glycoside(saponin)withglycyrrhetinicacid,whichiscondensedwith
O
-β-d-glucuronosyl-(1ʹ→2)-
β-d-glucuronic acid (Figure 4.5). After harvest, the roots are dried to 10% moisture, shredded,
extractedwithaqueousammonia,concentratedinvacuumevaporators,precipitatedwithsulfuric
acid,andcrystallizedwith95%alcoholprovidingacrudeammoniumglycyrrhizin(AG).Further
treatmentyieldsawhite,crystallinemono-ammoniumglycyrrhizin(MAG).Bothderivativeshave
CO
2
H
O
H
RO
H
GL
3MGA
GA
R = glucUA-glucUA
R = glucUA
R = H
Figure 4.5
Chemical structures of glycyrrhizin (GL) and its metabolites: 3-monoglucuronyl-glycyrrhetinic acid
(3MGA) and glycyrrhetinic acid (GA).
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