OMB First to Final Action Recommendation Checklist 11-12-18
ERP - GLUTEN ASSAYS: AOAC 2015.05 FAR
hydrolyzation step led to a loss of epitopes. Except for the concentration below the LoQ, CVs were around 10% and therefore acceptable. For detailed results see annex 2.
Table 2. Mean concentrations, SD and recovery of six independent extractions of partially‐hydrolyzed gliadin‐spiked syrup samples Hydrolyzed gliadin (wheat) in syrup spiked mean* SD CV recovery mg/kg mg/kg mg/kg % % 30 16.3 1.72 10.5 54 21 12.1 1.25 10.3 58 16 9.58 1.06 11.0 60 12 7.11 0.57 8.0 59 9 6.90 0.60 8.7 77 6 5.67 0.44 7.8 95 3 1.84** 0.46 25.0 61 Blank 1.82 * blank corrected ** concentrations below standard 2 (5 mg/kg) were extrapolated using 2 nd order polynomial function 3.2 Recovery and precision of spiked sourdough around 20 mg/kg (hydrolyzed) secalin Purified secalin in sourdough Results for sourdough spiked with intact secalin are depicted in table 3. As expected for an R5 antibody containing ELISA, there is an overestimation of secalin. The fact of decreasing recoveries at lower concentrations can be explained by (i) different affinities of the R5 antibody to the mixed calibrator of hydrolyzed wheat, rye and barley and the pure secalin from rye and (ii) different kinetic behavior of the hydrolyzed calibrator material compared to intact secalin which is quite larger in size. This leads to non‐parallel curves of the calibrator material and the intact secalin, so that a non‐constant factor between the two curves can be observed. Even for concentration at the LoQ the CV of 5.3% is quite excellent. For detailed results see annex 3. Table 3. Mean concentrations, SD and recovery of six independent extractions of secalin‐spiked sourdough samples secalin (rye) in sourdough spiked mean* SD CV rec mg/kg mg/kg mg/kg % % 15 45.1 4.9 10.9 297 10 22.7 3.8 16.7 221 5 7.60 0.40 5.3 140 2.5 3.85** 0.20 5.3 130 Blank 0.59 * blank corrected ** concentrations below standard 2 (5 mg/kg) were extrapolated using 2 nd order polynomial function
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