INRA, ENESAD, Université de Bourgogne, UMR1129 FLAVIC, F-21000 Dijon, France.
Magn Reson Chem. 2010 Apr;48(4):297-303. doi: 10.1002/mrc.2576.
The feasibility of solid-state magic angle spinning (MAS) (31)P nuclear magnetic resonance (NMR) spectroscopy and (23)Na NMR spectroscopy to investigate both phosphates and Na(+) ions distribution in semi-hard cheeses in a non-destructive way was studied. Two semi-hard cheeses of known composition were made with two different salt contents. (31)P Single-pulse excitation and cross-polarization MAS experiments allowed, for the first time, the identification and quantification of soluble and insoluble phosphates in the cheeses. The presence of a relatively 'mobile' fraction of colloidal phosphates was evidenced. The detection by (23)Na single-quantum NMR experiments of all the sodium ions in the cheeses was validated. The presence of a fraction of 'bound' sodium ions was evidenced by (23)Na double-quantum filtered NMR experiments. We demonstrated that NMR is a suitable tool to investigate both phosphates and Na(+) ions distributions in cheeses. The impact of the sodium content on the various phosphorus forms distribution was discussed and results demonstrated that NMR would be an important tool for the cheese industry for the processes controls.
采用固态魔角旋转（MAS）（31）P 核磁共振（NMR）光谱和（23）Na NMR 光谱法，以非破坏性方式研究半硬质奶酪中磷酸盐和 Na（+）离子分布的可行性。用两种不同盐含量的两种半硬质奶酪制作已知组成的奶酪。（31）P 单脉冲激发和交叉极化 MAS 实验首次允许鉴定和定量奶酪中的可溶性和不溶性磷酸盐。证明存在相对“移动”的胶体磷酸盐部分。通过（23）Na 单量子 NMR 实验验证了奶酪中所有钠离子的存在。（23）Na 双量子过滤 NMR 实验证明了“结合”钠离子的存在。我们证明 NMR 是研究奶酪中磷酸盐和 Na（+）离子分布的合适工具。讨论了钠含量对半硬质奶酪中各种磷形态分布的影响，结果表明 NMR 将成为奶酪工业过程控制的重要工具。
