Department of Animal Science, Food, and Nutrition (DIANA), Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; Department for Sustainable Food Process (DISTAS), Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy.
Parmigiano Reggiano Cheese Consortium, Via J.F. Kennedy, 18, Reggio Emilia 42124, Italy.
Food Res Int. 2021 Nov;149:110654. doi: 10.1016/j.foodres.2021.110654. Epub 2021 Aug 21.
Parmigiano Reggiano is a hard cheese with a Protected Designation of Origin (PDO) certification that also applies to the grated product. The percentage of rind in grated Parmigiano Reggiano is regulated by the PDO production Specification and must not exceed the limit of 18% (w/w). The present study evaluates the potential of an untargeted foodomics approach to detect anomalous inclusions of rind in grated Parmigiano Reggiano cheese. In particular, a combined metabolomics and peptidomics approach was used to detect potential markers of counterfeits (rind > 18%). In the framework of realistic food integrity purposes, non-Parmigiano Reggiano grated samples and different ripening times were also considered. Untargeted metabolomics allowed detecting 347 compounds, with a prevalence of amino acids and peptide derivatives, followed by fatty acyls and other compounds (such as lactones, ketones, and aldehydes) typically related to proteolysis and lipolysis events. Overall, the unsupervised multivariate statistics showed that the ripening time plays a hierarchically higher impact than rind inclusion in determining the main differences in the chemical profiles detected. Interestingly, supervised statistics highlighted distinctive markers for ripening time and rind inclusion, with only 16 common discriminant compounds being shared between the two conditions. The best markers of rind inclusion > 18% were 2-hydroxyadenine (VIP score = 1.937; AUC value = 0.83) and the amino acid derivatives argininic acid (VIP score = 1.462; AUC value = 0.75) and 5-hydroxyindole acetaldehyde (VIP score = 1.710; AUC value = 0.86). Interestingly, the medium-chain aldehyde 4-hydroperoxy-2-nonenal was a common marker of both ripening time and anomalous rind inclusion (>18%), likely arising from the lipid oxidation processes. Finally, among potential marker peptides of rind inclusion, the alpha-S1 casein proteolytic product (F)FVAPFPEVFGK(E) could be identified.
帕尔玛干酪是一种具有受保护原产地名称 (PDO) 认证的硬奶酪，也适用于磨碎产品。磨碎的帕尔玛干酪的外皮含量受 PDO 生产规范的限制，不得超过 18%（w/w）的限制。本研究评估了一种非靶向食品组学方法检测磨碎帕尔玛干酪中异常外皮的潜力。特别是，使用代谢组学和肽组学相结合的方法来检测潜在的假冒（外皮>18%）标志物。在现实的食品完整性目的框架内，还考虑了非帕尔玛干酪磨碎样品和不同的成熟时间。非靶向代谢组学检测到 347 种化合物，其中以氨基酸和肽衍生物为主，其次是脂肪酸酰基和其他化合物（如内酯、酮和醛），这些化合物通常与蛋白水解和脂解事件有关。总体而言，无监督多元统计分析表明，成熟时间比外皮含量对确定所检测化学特征的主要差异具有更高的层次影响。有趣的是，有监督统计数据突出了成熟时间和外皮含量的独特标志物，只有 16 种共同的判别化合物在两种情况下共享。外皮含量>18%的最佳标志物是 2-羟基腺嘌呤（VIP 得分=1.937；AUC 值=0.83）和氨基酸衍生物精氨酸（VIP 得分=1.462；AUC 值=0.75）和 5-羟基吲哚乙醛（VIP 得分=1.710；AUC 值=0.86）。有趣的是，中链醛 4-羟基-2-壬烯醛是成熟时间和异常外皮含量（>18%）的共同标志物，可能源于脂质氧化过程。最后，在外皮含量的潜在标志物肽中，可鉴定出 alpha-S1 酪蛋白的蛋白水解产物（F）FVAPFPEVFGK（E）。
