Locate guide values inTable
997.08D
. (
Note
: Prepare 2 different
dilutions of the same test solution if large difference between
concentrations of different sugar compounds to be analyzed is
expected.)
For foodswith fat content ofmore than5
´
fructan content, defat
diluted, filteredsolutionsbefore injectionas follows:Transferca4g
dilutedsolution in reaction tubeandadd4mLhexane.Agitate5min
onvortexmixtureandcentrifuge to separatehexanephase.Discard
hexane phase.
Filter aqueous phase through glass microfiber filters,
B
(
j
), and
then through 0.2
m
mmembrane filter before injection.
(
Note
: Use of internal standardization method is optional.
Alternatively, external standardizationmethod can be applied. Use
the same procedure as internal standardizationmethod but without
using internal standard. The response factor is then related to the
response of standard compound itself.)
(
b
)
Determination
.—Ensure that the same type of integration is
used on unknown test and standardworking solutions by choosing
peak width, threshold settings, and other integration parameters.
Carefully control baseline selection. Use peak height or peak area
for quantification.
Establish system’s linearity by running sugarsworking standard
solutions S
1
, S
2
, and S
3
. Run analysis by bracketing duplicate test
solutionswith sugarsworking standard solutions (e.g., S
1
, test 1A
0
,
test1A
1
,S
2
, test1A
2
, test2A
0
,S
3
, test2A
1
, test2A
2
,S
1
, test3A
0
, test
3A
1
, S
2
, etc.). Continue until all solutions have been analyzed.
Use average response factors from sugars working standard
solutionsbracketing tests tocalculate sugar concentrations for each
test solution.
(
c
)
Possible interferences
.—For products containing maltitol
and/or lactose (e.g., some chocolate, chocolate paste, cheese, and
breakfast drinks), glucose results after hydrolysis may be
overestimated.Therefore, calculatemaltitol content inproductsand
correct glucose results for that part of maltitol that has been
hydrolyzed by inulinase solution. Correct glucose results also for
that part of galactose that has been formedbyhydrolysis of lactose
by inulinase solution.
H. Calculations
Calculate response factors,
R
, of fructose, glucose, sucrose,
maltitol, and galactose as follows:
R=
(
C/C
¢
)
´
(
P
¢
/P
)
where
C
= concentration of sugar standard in working standard
solution, mg/kg;
C
¢
= concentration of glucoheptose (internal
standard), mg/kg;
P
= height of sugar peak;
P
¢
= height of
glucoheptose peak.
Using Table
997.08E
calculate fructose and sucrose content in
diluted solutions fromassayA
1
, and fructoseandglucosecontent in
diluted solutions from assayA
2
.
Calculate maltitol and galactose contents in diluted solutions
from assays A
1
and A
2
as follows (use corresponding response
factors and peak height [or peak area] of the components):
C
s
=
R
´
¢
C
s
´
(
P
s
/
¢
P
s
)
where
C
s
=concentrationof sugar indiluted test solution,mg/kg;
R
= response factor;
¢
C
s
= concentration of glocoheptose (internal
standard) indiluted test solution,mg/kg;
P
s
=heightofsugarpeak in
diluted test solution;
¢
P
s
=height ofglucoheptosepeak indiluted test
solution.
Calculate free fructose (
F
f
) and sucrose (S) contents; glucose (
G
1
),
maltitol (Mal
1
), and galactose (Gal
1
) contents after hydrolysis with
amyloglucosidase; and total glucose (
G
t
) and total fructose (
F
t
)
contents; and maltitol (Mal
2
) and galactose (Gal
2
) contents after
hydrolysiswith inulinase solution inpercent of initial test portion as
follows:
F
f
=
C M
M M
Ff
´
´ ´
2
1
7
100
where
C
Ff
=mg fructose/kg diluted solution assayA
0
.
S
=
C M
M M
S
´
´ ´
2
1
7
100
where
C
S
=mg sucrose/kg diluted solution assayA
0
.
G
1
=
C M M
M M M
G1
´ ´
´ ´ ´
2
4
1
3
8
100
where
C
G1
=mg glucose/kg diluted solution assayA
1
.
Mal
1
=
C M M
M M M
Mal1
´ ´
´ ´ ´
2
4
1
3
8
100
where
C
Mal1
=mgmaltitol/kg diluted solution assayA
1
.
Gal
1
=
C M M
M M M
Gal1
´ ´
´ ´ ´
2
4
1
3
8
100
where
C
Gal1
=mg galactose/kg diluted solution assayA
1
.
G
t
=
C M M M
M M M M
Gt
´ ´ ´
´ ´ ´ ´
2
4
6
1
3
5
9
100
where
C
Gt
=mg glucose/kg diluted solution assayA
2
.
ã
2013AOAC INTERNATIONAL
Table 997.08E. Calculationsof sugar contents in test
samples
Sugar
Assay
A
0
A
1
A
3
Glucose
G
1
a
G
t
b
Fructose
F
f
c
F
t
d
Sucrose
S
e
Maltitol
Mal
1
f
Mal
2
g
Galactose
Gal
1
h
Gal
2
i
a
G
1
=Sumof freeglucose (G
f
) andglucose frommaltodextrinsand starch
(G
m
).
b
G
t
=Total amount of glucose.
c
F
f
=Amount of free fructose in g/100 g initial test portion.
d
F
t
=Total amount of fructose.
e
S=Amount of sucrose in g/100 g initial test portion.
f
Mal
1
=Amount of maltitol before inulinase hydrolysis.
g
Mal
2
=Amount of maltitol after inulinase hydrolysis.
h
Gal
1
=Amount of galactose before inulinase hydrolysis.
i
Gal
2
=Amount of galactose after inulinase hydrolysis.
FOS-01
FORWORKINGGROUP/ERPUSEONLY
DONOTDISTRIBUTE
