Core Science Resources Group, Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, UK.
Food Chem. 2023 Mar 15;404(Pt B):134649. doi: 10.1016/j.foodchem.2022.134649. Epub 2022 Oct 18.
60 MHz proton NMR spectroscopy was used to analyse extracts from saffron spice and a range of potential adulterants and mixtures. Using a simple extraction procedure, good quality spectra were obtained which contain peaks from the characteristic metabolites picrocrocin and crocins, fatty acids and kaempferol. The spectra of samples from trusted suppliers were used to train one-class classification models by SIMCA, nearest neighbour and isolation forest methods. Applying these to spectra of saffron samples purchased from the online marketplace, it was found that 7 out of 33 samples were highly anomalous. From comparison with the spectra of known mixtures and confirmatory spectral analysis using 600 MHz NMR, it is probable that these contain considerable amounts of undisclosed foreign matter.
采用 60MHz 质子 NMR 光谱法分析藏红花香料及其一系列潜在掺杂物和混合物的提取物。通过简单的提取程序，获得了高质量的光谱，其中包含来自特征代谢物吡喃葡萄糖酸和藏红花酸、脂肪酸和山柰酚的峰。使用来自可信赖供应商的样品光谱，通过 SIMCA、最近邻和隔离森林方法训练单类分类模型。将这些方法应用于从在线市场购买的藏红花样品的光谱，发现 33 个样品中有 7 个高度异常。通过与已知混合物的光谱比较，并使用 600MHz NMR 进行确认性光谱分析，这些样品中可能含有相当数量的未公开的外来物质。
