AOAC OMB Final Action Recommendation (December 2019)-2016.14

2016.14 (October 2019) – FOS-03 MANUSCRIPT

FOR ERP USE ONLY DO NOT DISTRIBUTE

(d) Dilution .—The solutions prepared above are further diluted depending on the expected 1 fructan content (suggested dilutions are given in Table 2016.14C ) and the resulting 2 solution is “Solution B”. 3 Table 2016.14C. Scheme for sample dilution depending on expected fructan content 4

Expected fructan content, g/100 g

Dilution

Dilution factor, D

Volume of Solution A, mL

Final Volume, mL

Powder

Ready-to-feed

0.2 – 4.0 2.5 – 45 25 – 100

0.03 – 0.45

No dilution

No dilution

1

0.3 – 4.5 3.0 – 45

5

50 50

10

0.5

100

5 (e) Hydrolysis of sucrose and α-glucans.— Transfer 200 µL Solution B H(d) into a 1.5-mL 6 microtube, add 100 µL of N,N’ -diacetylchitobiose internal standard solution D(d) and 7 200 µL sucrase/ β -amylase/pullulanase/maltase enzyme mixture D(j) . Mix well (vortex), 8 place the microtubes on a floating rack and incubate at 40 °C for 90 min. Cool down to 9 room temperature. NOTE: Adapt these conditions (time and temperature) according to 10 enzyme manufacturer recommendations. 11 (f) Optional Carrez Clarification .—(Use in case of difficulties passing sample through SPE.) 12 Add 10 µL Carrez I solution D(g) to the sample and mix well. Then add 10 µL Carrez II 13 solution D(h) and mix again. Centrifuge at 10 000 x g for 10 min and use the supernatant 14 for the next step H(g) . 15 (g) Removal of monosaccharides.— Prepare the graphitized carbon SPE columns B(l) , as 16 follows (try to avoid passing air through the SPE column before the final elution step (g) 17 as this may result in higher blank measurements): 18 a. Flush with 3 × 400 µL SPE wash solution D(l) . 19 b. Flush with 3 × 400 µL water. 20

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