AOAC OMB Final Action Recommendation (December 2019)-2016.14
2016.14 (October 2019) – FOS-03 METHOD
FOR ERP USE ONLY DO NOT DISTRIBUTE
Infant formula powder FOS/GOS based e
10 (2)
0.0308
3.60
11.7
1.7
Infant formula powder milk based e
12 (0)
0.264
5.26
14.6
3.0
a Number of laboratories considered in the evaluation (number of laboratories with data removed as outliers). 13 b Results are reported in g/100 g of product as consumed (reconstituted or RTF). 14 c Reconstitution rate: 10 g product + 90 g water. 15 d RTF = Ready-to-feed. 16 e Reconstitution rate: 25 g product + 200 g water. 17 f HorRat is not necessary applicable to methods with indefinite analytes like polymers [12] such as fructans. 18 A. Principle 19
20
Samples are reconstituted in water (if required) and further diluted until the concentration of
21
fructan in solution is such that after hydrolysis the fructose and glucose concentrations will be
22
within the range covered by the standard curve. The diluted sample is treated with a mixture of
23
sucrase and α-glucanases to hydrolyse sucrose and α -glucooligosaccharides to their constituent
24
monosaccharides. The sample is passed through a solid phase extraction (SPE) column packed
25
with graphitized carbon. Salts and monosaccharides pass through and are washed away, while
26
the fructans are retained. Fructans are released from the column using an acetonitrile solution.
27
The released fructans are hydrolysed with a fructanase mixture, and the released glucose and
28
fructose are analysed by high performance anion-exchange chromatography with pulsed
29
amperometric detection (HPAEC-PAD). The fructan content is calculated by summing the glucose
30
and 0.9 × the fructose contents measured. In some matrices, a blank correction may be necessary
31
and can be applied.
B.
Apparatus and Materials
32
(a) Analytical balance. —Readability of 0.1 mg.
33
(b) pH-meter. —Readability of 0.1 pH.
34
2
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