6. AOACSPIFANMethods-2018Awards

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1586  H aselberger & J acobs : J ournal of AOAC I nternational V ol . 99, N o . 6, 2016

Figure 3. Example of product containing scFOS at ~0.28 g/100 g (Part I) – Upper trace: inulin (Beneo Orafti HP); middle trace: SPIFAN child formula powder, 00866RF00; lower trace: Ingredion Nutraflora scFOS. Time interval from 36–44 min zoomed in to show detail.

powder, milk based. All of the average recoveries were with the acceptable range of 90–110%, as specified in SMPR 2014.002.

that could complicate CF assignment following the guidance for Part I analysis.

Minimum Detection Limit (MDL)/LOQ

Precision

The LOQ was empirically demonstrated by analysis of a low- level spike solution, also containing a high level of sucrose. scFOS was spiked into laboratory water at a concentration of 0.03 g/100 g. Sucrose was added to this sample at a concentration of 9 g/100 g. This solution was analyzed in triplicate on each of 3 days. Average recovery, repeatability, and intermediate precision were calculated from this data. Linearity A graphical summary of the relative errors for each standard from the 43 calibration data sets is presented in Figure 2. These results indicate that, consistent with expectations, uncertainty (as evidenced by the dispersion) increases as concentration decreases. However there is no significant evidence of a concentration dependent bias and relative calibration errors are less than 4% for every individual standard. Consequently, it can be concluded that fit of calibration data to the quadratic model is consistently acceptable. Results and Discussion

Precision metrics are summarized in Table 2016.06A . Repeatability RSDs (RSD r ) ranged from 1.09 to 3.67%, all well below the requirement of 6%. Intermediate precision RSDs (RSD IP ) ranged from 2.57 to 6.79%. Intermediate precision requirements are not explicitly called out in SPIFAN SMPRs, however, in all but one case, intermediate precision performance met the stated requirement for repeatability. As indicated in Table 2, no detectable fructose was found in any of the unfortified SPIFAN products when they were subjected to quantitative testing (Part II) for total fructan content. Because of the diversity of these matrixes, including carbohydrate systems, this is good evidence of the ability to selectively detect fructans (as enzymatically released fructose). Example chromatograms relevant to the qualitative Part I analysis for CF assignment are shown in Figures 3–5. Maltodextrin-containing matrixes tend to be potentially the most problematic, especially with respect to assessing the presence or absence of GF 3 and/or GF 4 . It is important, though, to recognize that this step is not a screening tool to confirm whether or not fructans are present. It is intended only to provide sufficient information to allow selection of the most appropriate correction factor. The quantitative determination of enzymatically released fructose not only provides the basis for Specificity

Accuracy (Spike Recovery)

Results of the various recovery experiments are summarized in Tables 2016.06B , 2016.06C , and Table 1. Average recoveries ranged from 92.9 to 108%. The lowest recoveries (92.9 and 94.2%) were obtained for scFOS from the SPIFAN adult Nutritional RTF high-fat product, while the highest (108 and 105%) were for oligofructose from the SPIFAN toddler formula