AOACSPIFANMethods-2017Awards

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B runt et al .: J ournal of aoaC I nternatIonal V ol . 100, n o . 3, 2017 1

INFANT FORMULA AND ADULT NUTRITIONALS

Dual-Laboratory Validation of a Method for the Determination of Fructans in Infant Formula and Adult Nutritionals: First Action 2016.14 K ommer B runt Rotating Disc BV, 9753 HV Haren, The Netherlands P eter S anderS Eurofins Carbohydrate Competence Centre, 8440 AT Heerenveen, The Netherlands V éronique S Pichtig Nestlé Research Centre, 1000 Lausanne, Switzerland V eronica e rnSte -n ota Eurofins Carbohydrate Competence Centre, 8440 AT Heerenveen, The Netherlands P aulina S awicKa Nestlé Research Centre, 1000 Lausanne, Switzerland; Robert Gordon University, Aberdeen, AB10 7AQ, United Kingdom; North East Scotland College, Aberdeen, AB25 1BN, United Kingdom K imBerley i wanoff Nestlé Quality Assurance Centre, York, United Kingdom J eroen V an S oeSt Eurofins Carbohydrate Competence Centre, 8440 AT Heerenveen, The Netherlands P aul K ong t hoo l in Robert Gordon University, Aberdeen, AB10 7AQ, United Kingdom S ean a uStin 1 Nestlé Research Centre, 1000 Lausanne, Switzerland

Until recently, only two AOAC Official Methods SM have been available for the analysis of fructans: Method 997.08 and Method 999.03. Both are based on the analysis of the fructan component monosaccharides (glucose and fructose) after hydrolysis. The two methods have some limitations due to the strategies used for removing background interferences (such as from sucrose, α-glucooligosaccharides, and free sugars). The method described in this paper has been developed to overcome those limitations. The method is largely based on Method 999.03 and uses combined enzymatic and SPE steps to remove the interfering components without impacting the final analytical result. The method has been validated in two laboratories on infant formula and adult nutritionals. Recoveries were in the range of 86–119%, with most being in the range of 91–104%. RSD r values were in the range of 0.7–2.6%, with one exception when the fructan concentration was close to the LOQ, resulting in an RSD r of 8.9%. The performance is generally within the requirements outlined in the Received January 6, 2017. Accepted by SG January 26, 2017. This method was approved by the AOAC Expert Review Panel for SPIFAN Nutrient Methods as First Action. The Expert Review Panel for SPIFAN Nutrient Methods invites method users to provide feedback on the First Action methods. Feedback from method users will help verify that the methods are fit-for-purpose and are critical for gaining global recognition and acceptance of the methods. Comments can be sent directly to the corresponding author or methodfeedback@aoac.org. 1 Corresponding author’s e-mail: sean.austin@rdls.nestle.com DOI: 10.5740/jaoacint.17-0007

AOAC Standard Method Performance Requirements (SMPR ® 2014.002), which specifies recoveries in the range of 90–110% and RSD r values below 6%. I nulin and fructooligosaccharides (FOS) are increasingly being used as health-enhancing ingredients in a diverse range of foods, feed, and pet food products. Both inulin and FOS pass the stomach and small intestine unchanged and are fermented in the large intestine where they stimulate the growth and/or activity of bacteria like lactobacilli and bifidobacteria, which may be beneficial to health (1, 2). Historically, two different official AOAC Methods have been available for the determination of the total fructan content in food products: Official Method SM 997.08 (3) and Official Method 999.03 (4). The different underlying principles of the two methods result in each method having different advantages and disadvantages. Prior knowledge of the sample composition (content of sugars, maltodextrins, and starch) and of the fructan composition (presence of short-chain oligofructose) is necessary to be able to select the best approach. In Method 997.08 (3), the free fructose and sucrose content must first be quantified chromatographically. In the next step, after enzymatic conversion of starch and maltodextrins, glucose is again measured chromatographically. In the third step, inulin/ FOS and sucrose are completely converted into glucose and fructose, and then the released monosaccharides are determined chromatographically. The fructan content is calculated by subtracting the glucose, sucrose, and fructose content measured in steps 1 and 2 from the total fructose and glucose content measured in step 3. This implies that large corrections have to be made for samples containing large quantities of fructose,