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Memo
Monique Steegmans
16001n-MSS-MSS-SLV FOS01 AOAC997.08 Beneo-Orafti, 1 Febr 2016, page 13/18
products of different origin (sugar and chicory) and DP range. The spiking/recovery ranges from
96.9 to 107.1% with a mean of 100.3%, which is very well meeting the proposed requirement of
90-110%. The very low concentrations (spike level 0.05 near to LOQ) are included during this
spiking test and even these meet the proposed range.
The precision and accuracy are part of the performance of the proposed method, and
as the Test Materials Kit contains fortified samples with unknown amounts, the recovery of those
should also be calculated. Comparing the spiked amounts of fructan in the Test Materials Kit with
the reported fructan results of each proposed method provides information about of
the
performance
of the FOS method proposed. This can’t be done by the author but is still a task to
be done for every method proposed for FOS determination.
The method as proposed corrects for the glucose part but in contrast to the methods that treat the
samples by borohydride (Cuany et al: Journal of AOAC int. Vol93, N°1, 2010) to get rid of the
reducing sugars, this method FOS-01 does not have to correct for the missing part of the F
m
chains. Consequently the influence of the factor is smaller in comparison with the methods based
on the Cuany method. In case the type of inulin that is added can’t be identified, a mean factor can
be applied which influences the final fructan content not significantly. The applied factor for
oligofructose derived from chicory or sugar is also different as the ratio fructose to glucose coming
from the fructans is very different.
HPAEC has the disadvantage that every 6 injections samples have to be bracketed with standards.
Annex 1 Chromatogram of a standard.
Annex 2 Calibration curve for Fructose and Sucrose.
Annex 3 Chromatogram of a sample J4G0975 (Infant elemental powder
00403RF00)
before and
after incubation with inulinase.
Annex 4 Detailed results for the precision.
Annex 5 Detailed results for the recovery.
References.
1) AOAC 997.08 Official method for fructans in food and feed.
2) Collaborative study report AOAC 997.08
3) Ströber method. (
J. Agric. Food Chem.
, 2004, 52 (8), 2137-2146)
4) Codex Alimentarius Council directive 90/496/EEC 12 Dec 2012
5) Cuany et al: Journal of AOAC int. Vol93, N°1, 2010
Tiense suikerraffinaderij/ Beneo-Orafti (part of Südzucker group)
Central Department Research, Development and Services-Analytics-Tienen
Monique Steegmans
Fos-01 (February 2016)
FOR ERP USE ONLY
DO NOT DISTRIBUTE