Fritz Ronald D, Chen Yumin, Contreras Veronica
PepsiCo, Inc. Global R&D, Measurement Sciences, 617 W. Main Street, Barrington, IL 60010, USA.
PepsiCo, Inc. Global R&D, Measurement Sciences, 617 W. Main Street, Barrington, IL 60010, USA.
Food Chem. 2017 Feb 1;216:170-5. doi: 10.1016/j.foodchem.2016.08.031. Epub 2016 Aug 12.
Oats are easily contaminated with gluten-rich kernels of wheat, rye and barley. These contaminants are like gluten 'pills', shown here to skew gluten analysis results. Using R-Biopharm R5 ELISA, we quantified gluten in gluten-free oatmeal servings from an in-market survey. For samples with a 5-20ppm reading on a first test, replicate analyses provided results ranging <5ppm to >160ppm. This suggests sample grinding may inadequately disperse gluten to allow a single accurate gluten assessment. To ascertain this, and characterize the distribution of 0.25-g gluten test results for kernel contaminated oats, twelve 50g samples of pure oats, each spiked with a wheat kernel, showed that 0.25g test results followed log-normal-like distributions. With this, we estimate probabilities of mis-assessment for a 'single measure/sample' relative to the <20ppm regulatory threshold, and derive an equation relating the probability of mis-assessment to sample average gluten content.
燕麦很容易被富含麸质的小麦、黑麦和大麦籽粒污染。这些污染物就像麸质“药丸”，如图所示会使麸质分析结果产生偏差。我们使用R-Biopharm R5酶联免疫吸附测定法，对市场调查中无麸质燕麦片的麸质含量进行了定量分析。对于首次检测读数为5-20ppm的样本，重复分析得到的结果范围为<5ppm至>160ppm。这表明样本研磨可能无法充分分散麸质，从而无法进行单一准确的麸质评估。为了确定这一点，并描述被籽粒污染的燕麦0.25克麸质检测结果的分布情况，我们对十二个50克的纯燕麦样本进行了检测，每个样本都添加了一粒小麦籽粒，结果显示0.25克检测结果呈对数正态分布。据此，我们估计了相对于<20ppm监管阈值的“单次测量/样本”误判概率，并推导出一个将误判概率与样本平均麸质含量相关联的方程。
