Abstract With the addition of reference spectra and 1H 31P cross-polarisation kinetics we have increased the analysis available by 31P NMR of the cheese ageing process. A previous study demonstrated that solid-state 31P NMR can be used to monitor the state of phosphorus in ageing cheeses. It is possible to differentiate between the mobile and immobile phosphorus species present in the cheese casein micelles. In this work, proton to phosphorus cross polarisation (CP) kinetic experiments (1H 31P CP-MAS) (where MAS = magic angle spinning) enable the observation of the state of the colloidal calcium phosphate (CCP) and phosphoserine (PSer) separately in the casein micelles. Also, 1H 31P CP-MAS spectra can be used to indirectly monitor the levels of micellar calcium. From the data gathered, we were able to conclude these points about the ageing process of Mozzarella cheese; in the first 20 days the cheese texture is dependent on the dynamics of free water and immobile calcium and phosphate, the CCP phosphate is mobilised at an exponential rate with the majority mobilised within the first 20 days, the driving force for CCP mobilisation is possibly the migration of water from the cheese serum into the casein proteins and CCP phosphorus is preferentially mobilised while immobile phosphoserine levels remains relatively unchanged during the early (40 days) of Mozzarella cheese ageing.

中文翻译：

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扩展固态磷核磁共振对马苏里拉奶酪老化的洞察

摘要 通过添加参考光谱和 1H 31P 交叉极化动力学，我们增加了 31P NMR 对奶酪老化过程的可用分析。之前的一项研究表明，固态 31P NMR 可用于监测老化奶酪中的磷状态。可以区分奶酪酪蛋白胶束中存在的移动和固定磷种类。在这项工作中，质子到磷的交叉极化 (CP) 动力学实验 (1H 31P CP-MAS)（其中 MAS = 魔角旋转）能够分别观察胶体磷酸钙 (CCP) 和磷酸丝氨酸 (PSer) 的状态酪蛋白胶束。此外，1H 31P CP-MAS 光谱可用于间接监测胶束钙的水平。从收集到的数据来看，我们能够总结出关于马苏里拉奶酪老化过程的这些要点；在前 20 天，奶酪质地取决于游离水和固定钙和磷酸盐的动力学，CCP 磷酸盐以指数速率动员，大多数在前 20 天内动员，CCP 动员的驱动力可能是在马苏里拉奶酪老化的早期（40 天）期间，水从奶酪血清迁移到酪蛋白和 CCP 磷中优先动员，而固定的磷酸丝氨酸水平保持相对不变。