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CH
2
OH
CH
2
OH
O
O
H
OH
H
H
H
OH
O
OH
H
H
OH
H
H
H
OH
H
OH
Figure 2.19
Structure of cellobiose.
starchbymaltases,andithasacharacteristiclavorofmalt.Itisareadilyyeast-fermentablesugar,
reducesFehling'ssolution,iseasilysolubleinwaterandslightlysolubleinethanol,andpresents
mutarotation(deMan1999).
Cellobiose
:Cellobioseisareducingdisaccharideformedfromtwounitsofglucosejoinedwith
aβ-(1→4)glycosidicbond(Figure2.19).Itcanbeobtainedbyenzymaticoracidhydrolysisofcel-
lulose.Cellobioseisdifferentiatedfrommaltoseinthekindofglycosidicbondbetweentheglucose
units.Itisenzymaticallyhydrolyzedbytheenzymeemulsine(deMan1999).
2.4.2 trisaccharides and tetrasaccharides
Themostimportanttrisaccharideisrafinosethatiscomposedofgalactose,glucose,andfruc-
tose(Figure2.20).Itcanbefoundinseeds,roots,andundergroundstems(Meyer1987).Itisalso
foundinsugarbeetsfromwhereitisisolated.Rafinosenegativelyimpactssugarbeetprocessing
Manninotriose
Galactobiose
Melibiose
CH
2
OH
CH
2
CH
2
O
O
O
OH
H
O
H
OH
H
O
O
HOH
2
C
H
H
H
O
H
H
H
H
OH
H
OH
H
O
H
H
HO
HO
CH
2
OH
H
OH
H
OH
H
OH
OH
H
Galactose
Galactose
Galactose
Fructose
Sucrose
Raffinose
Stachyose
Figure 2.20
Composition of some major oligosaccharides occurring in foods. (Adapted from Shallenberger,
R. S. and Birch, G. G.,
Sugar Chemistry
, AVI Publishing, Co. Inc., London, 1975.)
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