55 / 258
B
runt
et al
.:
J
ournal of
aoaC I
nternatIonal
V
ol
.
100, n
o
.
3, 2017
1
Dual-Laboratory Validation of a Method for the
Determination of Fructans in Infant Formula and Adult
Nutritionals: First Action 2016.14
K
ommer
B
runt
Rotating Disc BV, 9753 HV Haren, The Netherlands
P
eter
S
anderS
Eurofins Carbohydrate Competence Centre, 8440 AT Heerenveen, The Netherlands
V
éronique
S
Pichtig
Nestlé Research Centre, 1000 Lausanne, Switzerland
V
eronica
e
rnSte
-n
ota
Eurofins Carbohydrate Competence Centre, 8440 AT Heerenveen, The Netherlands
P
aulina
S
awicKa
Nestlé Research Centre, 1000 Lausanne, Switzerland; Robert Gordon University, Aberdeen, AB10 7AQ, United Kingdom; North
East Scotland College, Aberdeen, AB25 1BN, United Kingdom
K
imBerley
i
wanoff
Nestlé Quality Assurance Centre, York, United Kingdom
J
eroen
V
an
S
oeSt
Eurofins Carbohydrate Competence Centre, 8440 AT Heerenveen, The Netherlands
P
aul
K
ong
t
hoo
l
in
Robert Gordon University, Aberdeen, AB10 7AQ, United Kingdom
S
ean
a
uStin
1
Nestlé Research Centre, 1000 Lausanne, Switzerland
Until recently, only two AOAC
Official Methods
SM
have been available for the analysis of fructans:
Method 997.08 and Method 999.03. Both are
based on the analysis of the fructan component
monosaccharides (glucose and fructose)
after hydrolysis. The two methods have some
limitations due to the strategies used for removing
background interferences (such as from sucrose,
α-glucooligosaccharides, and free sugars). The
method described in this paper has been developed
to overcome those limitations. The method is
largely based on Method 999.03 and uses combined
enzymatic and SPE steps to remove the interfering
components without impacting the final analytical
result. The method has been validated in two
laboratories on infant formula and adult nutritionals.
Recoveries were in the range of 86–119%, with most
being in the range of 91–104%. RSD
r
values were
in the range of 0.7–2.6%, with one exception when
the fructan concentration was close to the LOQ,
resulting in an RSD
r
of 8.9%. The performance is
generally within the requirements outlined in the
AOAC
Standard Method Performance Requirements
(SMPR
®
2014.002), which specifies recoveries in the
range of 90–110% and RSD
r
values below 6%.
I
nulin and fructooligosaccharides (FOS) are increasingly
being used as health-enhancing ingredients in a diverse
range of foods, feed, and pet food products. Both inulin and
FOS pass the stomach and small intestine unchanged and are
fermented in the large intestine where they stimulate the growth
and/or activity of bacteria like lactobacilli and bifidobacteria,
which may be beneficial to health (1, 2).
Historically, two different official AOAC Methods have
been available for the determination of the total fructan content
in food products:
Official Method
SM
997.08
(3) and
Official
Method
999.03
(4). The different underlying principles of the
two methods result in each method having different advantages
and disadvantages. Prior knowledge of the sample composition
(content of sugars, maltodextrins, and starch) and of the fructan
composition (presence of short-chain oligofructose) is necessary
to be able to select the best approach.
In Method
997.08
(3), the free fructose and sucrose content
must first be quantified chromatographically. In the next step,
after enzymatic conversion of starch and maltodextrins, glucose
is again measured chromatographically. In the third step, inulin/
FOS and sucrose are completely converted into glucose and
fructose, and then the released monosaccharides are determined
chromatographically. The fructan content is calculated by
subtracting the glucose, sucrose, and fructose content measured
in steps 1 and 2 from the total fructose and glucose content
measured in step 3. This implies that large corrections have to
be made for samples containing large quantities of fructose,
INFANT FORMULA AND ADULT NUTRITIONALS
Received January 6, 2017. Accepted by SG January 26, 2017.
This method was approved by the AOAC Expert Review Panel for
SPIFAN Nutrient Methods as First Action.
The Expert Review Panel for SPIFAN Nutrient Methods invites
method users to provide feedback on the First Action methods.
Feedback from method users will help verify that the methods are
fit-for-purpose and are critical for gaining global recognition and
acceptance of the methods. Comments can be sent directly to the
corresponding author or
methodfeedback@aoac.org.
1
Corresponding author’s e-mail:
sean.austin@rdls.nestle.comDOI: 10.5740/jaoacint.17-0007
55