Chemical and Functional Properties of Food Saccharides

© 2004 by CRC Press LLC
TABLE 5.3
QSAR Correlation Analysis of Relative Sweetness, RS j, of
Sucrose/Galactosucrose Chlorodeoxy Derivatives by Equation 5.6
jth
Saccharide RS j (mole/mole)
Sugar–Receptor Interaction Energy
(kJ/mole)
Calculated ELST CT DISP
(Eq. 5.6) Expl. (Eq. 5.6a) (Eq. 5.6b) (Eq. 5.6c) Etot 1′, 4, 6′-TriClG 2656.06 2323.26 −0.013 −16.389 −6.786 −23.188
1′,4,6,6′-
TetraClG
1230.95 1215.52 3.180 −15.732 −8.749 −21.301
1′,4-DiClG 556.59 664.65 −0.059 −12.439 −-6.899 −19.397
1′,6′-DiClS 537.92 553.87 −0.142 −15.539 −3.594 −19.276
1′,4,6,6′-
TetraClS
239.14 243.10 3.180 −15.698 −4.761 −17.280
6′ClS 20.05 21.08 −0.155 −9.498 −1.548 −11.201
1′-ClS 23.15 21.08 −0.201 −8.581 −2.778 −11.560
4-ClS 5.45 5.27 0.013 −4.845 −3.167 −8.000
Sucrose 0.94 1.00 −0.184 −3.146 −0.372 −3.703
Galactosucrose 0.21 0.20 0.000 0.000 0.000 0.000
R 0.9996a S2 0.0816b a Correlation coefficient of the multiple regression, Equation 5.6.
b Remainder variance of the above multiple regression.
( 2)
⎛ 526. 705 ⎞
( 2) ( 2)
ECT ()=− j 2. 303RT⋅⎜
, (5.6b)
Rec
⎝ εLU − ε () j
⎟ CTj = ECT()− j ECT( G)
5 ⎠
( 2)
⎛ 1556. 877 1038. 128
Edisp()=− j 2. 303RT⋅⎜
−
Rec Rec #
c
⎝ ε ()− j ε ()+ j ε −ε
ε ()− j ε ()+ j ε −ε
# Re Rec
2 2 LU HO 2 7 LU HO
() 2
DISP = E j
j disp
2
()−Edisp
()
() G
(5.6c)
Primary sweetness effects belong to the CT sugar–receptor interactions. They are
included in this term as the 526.705 coefficient, which describes the n-electron
transfer from the fifth occupied saccharide orbital to the receptor LUMO. All five,
the most sweet sugars (RS j = 200–2000), have a high CT energy constituting about
60% contribution to the total, E tot, energy (Table 5.3). The LCAO (linear combination
of atomic orbitals) structure of the 5th occupied orbital indicates a significant
domination of the fructofuranose Cl-1′ and Cl-6′ atoms, identified as the E4 and E1
sweetener subsites, respectively.
⎞
⎟
⎠