Fructans in Foods and Food Products, Ion-Exchange Chromatographic Method: Collaborative Study

Nine collaborating laboratories assayed 6 blind duplicate pairs of food samples containing the fructans inulin or oligofructose. The 6 sample pairs ranged from low (4%) to high levels (40%). Following the proposed method, the samples were treated with amyloglucosidase and inulinase enzymes and the released sugars were determined byion exchange chromatography. Repeatability standard deviation ranged from 2.9 to 5.8%; reproducibility standard deviation ranged from 4.7 to 11.1%. The ion-exchange chromatographic method for determinationof fructans in food and food products has been adopted first action by AOAC INTERNATIONAL (997.08)

Determination of Low-Level Glucose and Fructose in Raw and Refined Crystalline Sugar by High-Performance Anion-Exchange Chromatography: Collaborative Study

A method was developed and a collaborative study was performed under the auspices of the International Commission of Uniform Methods for Sugar Analysis. The collaborators used high-performance anion-exchange chromatography (HPAEC) to determine trace amounts of glucose and fructose in 3 raw and 3 refined sugar samples provided as blind duplicates. Fourteen laboratories participated in the study. Although difficulties were experienced by a few analysts, 10 laboratories reported positive results. Average repeatabilities and reproducibilities for glucose and fructose in raw sugar were slightly above 5 and 10%, respectively, and the average Horwitz ratios were well under 2. Average repeatabilities and reproducibilities for glucose and fructose in refined sugar were 10 and 22%, respectively; although the Horwitz ratios were >2, they were marginal (2.8). The HPAEC results agreed with results obtained by gas chromatography in an independent laboratory. Because the method was collaboratively studied according to the protocol of the International Union of Pure and Applied Chemistry for collaborative studies, and the results meet its criteria, it is recommended that the method be adopted Official First Action by AOAC INTERNATIONAL.