Consonni R, Cagliani L R
Istituto per lo Studio delle Macromolecole, Lab. NMR, CNR, v. Bassini 15, 20133 Milan, Italy.
Talanta. 2008 Jun 30;76(1):200-5. doi: 10.1016/j.talanta.2008.02.022. Epub 2008 Mar 4.
Samples of Italian Parmigiano Reggiano cheese of different ripening stages (14, 24 and 30 months) were analyzed by (1)H NMR spectroscopy and the water-soluble metabolites content compared with samples of "Grana type" cheese from east Europe countries. Different multivariate statistical protocols were examined to build up a stable model for both ripening and geographical discrimination among the samples. The discriminant approach revealed a larger metabolite content increasing with ripening process; in particular younger samples were characterized by a higher content in leucine and isoleucine, while 30 months samples by a larger extent of threonine. The use of a classification approach resulted in a better discrimination of geographical samples. Foreign "Grana type" samples resulted well differentiated with respect to all Italian samples of Parmigiano Reggiano cheese. Foreign samples were characterized by a large amount of leucine and isoleucine, compounds that typified young Italian samples (14 months), and also by lactate, butanoate and acetate, thus suggesting short ripening for foreign samples. Parmigiano Reggiano samples were instead characterized by a large amount of all other compounds, in particular by threonine, which typified old samples (30 months), and other amino acids.
对处于不同成熟阶段（14个月、24个月和30个月）的意大利帕尔马干酪样品进行了¹H核磁共振光谱分析，并将其水溶性代谢物含量与来自东欧国家的“格拉纳型”奶酪样品进行了比较。研究了不同的多元统计方法，以建立一个关于样品成熟度和地理鉴别的稳定模型。判别分析方法显示，随着成熟过程，代谢物含量增加；特别是较年轻的样品中亮氨酸和异亮氨酸含量较高，而30个月的样品中苏氨酸含量较高。使用分类方法能更好地鉴别地理样品。外国的“格拉纳型”样品与所有意大利帕尔马干酪样品有明显差异。外国样品的特征是含有大量亮氨酸和异亮氨酸，这些化合物在年轻的意大利样品（14个月）中也有体现，此外还含有乳酸、丁酸和乙酸，这表明外国样品的成熟时间较短。相比之下，帕尔马干酪样品的特征是含有大量其他化合物，特别是苏氨酸，它是成熟时间较长的样品（30个月）的典型特征，以及其他氨基酸。
