Moisture migration of fresh‐cut apple during 4 °C storage was monitored by low‐field nuclear magnetic resonance (LF‐NMR) and magnetic resonance imaging (MRI). Three water components were identified in apple tissue by LF‐NMR T₂ relaxation, corresponding to water in cell wall, cytoplasm and vacuole. The relaxation results also revealed that the moisture migrated from the vacuole to cytoplasm and the mobility of water in vacuole decreased with the extension of storage time. T₂ weighted images of MRI indicated that high density of water appeared at the edge of the fresh‐cut apple in the later stage of storage. Breakdown of cell walls and intracellular network were observed by cryo scanning electron microscope (cryo‐SEM). Moreover, storage process also led to the decrease in moisture content, browning and softening of fresh‐cut apple. In addition, good prediction models have been developed for quality indicators using partial least squares regression based on Carr–Purcell–Meiboom–Gill decay data.

中文翻译：

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鲜切苹果贮藏期间水分迁移，微结构和质量变化的研究

通过低场核磁共振（LF-NMR）和磁共振成像（MRI）监测鲜切苹果在4°C储存期间的水分迁移。通过LF-NMR T ₂弛豫确定了苹果组织中的三种水分，分别对应于细胞壁，细胞质和液泡中的水分。弛豫结果还表明，水分从液泡迁移到细胞质，并且随着储存时间的延长，水在液泡中的迁移率降低。Ť ₂MRI的加权图像表明，在储存后期，鲜切苹果的边缘出现了高密度的水。通过冷冻扫描电子显微镜（cryo-SEM）观察到细胞壁和细胞内网络的破裂。此外，储存过程还导致鲜切苹果的水分含量降低，褐变和软化。此外，已经基于Carr–Purcell–Meiboom–Gill衰减数据，使用偏最小二乘回归为质量指标开发了良好的预测模型。