核磁共振技术在脐橙保藏和质量评估中的应用

NUCLEAR MAGNETIC RESONANCE TECHNIQUE APPLICATION IN EVALUATING THE QUALITY OF NAVEL ORANGE DURING STORAGE

采用低场核磁共振技术研究脐橙储藏过程中水分的状态、变化以及水分的迁移。利用Carr-Purcell-Mei-boom-Gill(CPMG)序列采集样品的核磁共振受激回波信号,采用多重指数衰减模型对收集的信号数据进行分析并计算组织中不同水分自旋-自旋弛豫时间。探讨脐橙在储藏过程中品质变化与核磁共振弛豫参数变化的相关性。发现在脐橙的后成熟期、稳定期和腐烂期,对应的自旋-自旋弛豫时间变化呈现一个上升-稳定-急速下降的过程,且在脐橙腐烂前出现了一个自旋-自旋驰豫时间急剧下降的过程。该方法可以作为脐橙质量评估的有效手段,对于脐橙的质量评估和保藏方法的评估等具有指导意义。

Low field Nuclear magnetic resonance technique was used to evaluate the quality and behavior of water in navel orange during storage in constant temperature and humidity. NMR Carr-Purcell-Meiboom-Gill （CPMG）sequence was used to acquire the samples＇ activated echo signals. A muh-exponential regress model was used to calculate the spin-spin relaxation time （T2） of samples in deferent storage period. The relative chemical contents such as acidity, reducing sugar et al were storage. A trend of T2 change was observed in the state analyzed at the same time during the deferent period of diagram T2 vs storage time. T2 values rises in the initial stage and then changed little in the following steady period and go down quickly at the end before the samples decay during the period of storage. A T2 going down quickly processing before decay were observed in nearly all samples. This method would be help for evaluating the quality of navel orange during storage in the future.