1
Determination of fructans in food
YufengLiu, DongLi, YajuanCui,MeiHe,MiaoLi
Beijing nutritionResources Institute, Beijing, China
1 Range
The fructan in food ismeasured by ion chromatography in thismethod.
Thismethod is suitable for themeasurement of additional fructan in foods includingmilk
and dairyproducts, infant formula foods, infant cereal complementary foods, beverages, and
wines, etc.
2 Principle
The sample is extracted byhotwater, the sucrose, maltodextrin and starch in the sample
solution are hydrolyzed by sucrasemixed enzyme to glucose and fructose, whichwill be reduced
by sodium borohydride to
sugar alcohols, excess sodium borohydride is neutralized by acetic
acid; the fructan is hydrolyzed to fructose and glucosewith purified fructanase (exo-inulinase
plus endo-inulinase), then the sample solution is filtered through 0.2μmmicroporousmembrane
and purification column and analyzed usinghigh performance anion exchange chromatography
with pulsed amperometric detector (HPAEC–PAD). Fructans are calculated from concentrations
of fructose.
3 Instruments and equipments
3.1Anion exchange chromatography(HPAEC): equippedwith quaternaryor above gradient
pump and pulsed amperometric detector (PAD).
3.2Column: anion exchange column (250×4mm id)with similar guard column (50×4mm id),
CarboPacPA1.
3.3 Analytical balance:with an accuracyof 0.1mg, 0.01 g.
3.4 pHmeter:with an accuracyof 0.01.
3.5Water bath shaker: 40
℃
~ 80
℃
.
3.6Centrifuge
：
Rotating speed≥3000 r/min.
3.7Purification column: reversed phase solid phase extraction (DionexOnGuard IIRP, 1cc).
3.8Millipore filter: 0.2μm porosity (nylon).
3.9Filter paper (
φ
11)
3.10Volumetric flasks: 10, 25, 50, 100, and 1000mL
3.11Erlenmeyer flasks 150mL
3.12Glass rod
3.13Hot plate (capable ofmaintaining100
°
C)
3.14Beakers: 50mL
3.15Polypropylene tubes: 2, 10,and 15mL
3.16Centrifuge tubewith plug, 100mL
3.17Glass tubewith plug, 10mL
3.18Micropipetors capable of accuratelydelivering: 50, 100, 200, 300, and 400µL
FOS-02
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