Magnetic resonance imaging applied to quality control of "ichidagaki" dried persimmon fruit

Abstract

Moisture distribution in KIchidagakiN dried persimmon fruit was examined to clarify the water-relatedd ifferences between sound and moldy samples by using magnetic resonance imaging (MRI). One moldy product was measured together with one or three sound samples by the spin-echo (SE) method with a small MRI system equipped with a 0.2-Tesla permanent magnet and a solenoid-type detector with a 12-cm2 opening. Differences in the moisture content and water activity values of the sound and moldy samples were not significant (p > 0.05). With NMR signal intensity expressed as brightness in the images, the mesocarp and endocarp tissues of the moldy samples were brighter than those of the sound samples. Endocarp tissues of the moldy samples produced especially bright images. This difference in brightness was found in all 2-D images horizontally sliced from 3-D images. The brighter the area in an MRI image, the higher the amount of water present. The T1 and T2 relaxation time-weighted imaging methods revealed that water mobility distributions of the moldy samples shifted upward and endocarp tissues of the moldy samples had higher water mobility. We found that MRI can be used to detect moisture distribution differences between sound and moldy samples of "Ichidagaki" dried persimmon fruit, and expect this practical application of MRI in the quality control of the fruit to be useful.