Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell'Aquila, Via Vetoio, 67010 L'Aquila, Italy.
Molecules. 2021 Nov 15;26(22):6875. doi: 10.3390/molecules26226875.
The multi-elemental composition of three typical Italian Pecorino cheeses, Protected Designation of Origin (PDO) Pecorino Romano (PR), PDO Pecorino Sardo (PS) and Pecorino di Farindola (PF), was determined by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The ICP-OES method here developed allowed the accurate and precise determination of eight major elements (Ba, Ca, Fe, K, Mg, Na, P, and Zn). The ICP-OES data acquired from 17 PR, 20 PS, and 16 PF samples were processed by unsupervised (Principal Component Analysis, PCA) and supervised (Partial Least Square-Discriminant Analysis, PLS-DA) multivariate methods. PCA revealed a relatively high variability of the multi-elemental composition within the samples of a given variety, and a fairly good separation of the Pecorino cheeses according to the geographical origin. Concerning the supervised classification, PLS-DA has allowed obtaining excellent results, both in calibration (in cross-validation) and in validation (on the external test set). In fact, the model led to a cross-validated total accuracy of 93.3% and a predictive accuracy of 91.3%, corresponding to 2 (over 23) misclassified test samples, indicating the adequacy of the model in discriminating Pecorino cheese in accordance with its origin.
三种典型的意大利佩科里诺奶酪（受保护的原产地名称（PDO）佩科里诺罗马诺（PR）、PDO 佩科里诺撒丁岛（PS）和佩科里诺·迪·法林多拉（PF））的多元素组成通过电感耦合等离子体发射光谱法（ICP-OES）进行了确定。这里开发的 ICP-OES 方法允许对 8 种主要元素（Ba、Ca、Fe、K、Mg、Na、P 和 Zn）进行准确和精确的测定。从 17 个 PR、20 个 PS 和 16 个 PF 样本中获得的 ICP-OES 数据通过无监督（主成分分析，PCA）和有监督（偏最小二乘判别分析，PLS-DA）多元方法进行处理。PCA 揭示了给定品种样本中多元素组成的相对高变异性，并且根据地理起源相当好地分离了佩科里诺奶酪。关于有监督分类，PLS-DA 能够获得出色的结果，无论是在交叉验证中的校准还是在外部测试集上的验证。事实上，该模型导致交叉验证总准确性为 93.3%，预测准确性为 91.3%，对应 2 个（超过 23 个）分类错误的测试样本，表明该模型能够根据其起源来区分佩科里诺奶酪。
