Objective: The objective of this research was to investigate the potential use of NMR for evaluating various internal quality factors of fruits and vegetables, leading to the eventual development of practical techniques that are useful for future development of NMR sensors. Summary: Investigation on NMR imaging, one-dimension NMR projection, and single-pulse free-induction-decay (FID) spectrum led to the development of high-speed NMR techniques for real-time sensing of internal quality of selected fruits. NMR imaging can be used for detecting internal defects and various quality factors such as bruises, dry regions, worm damage, stage of ripeness, tissue breakdown, and the presence of voids, seeds, sprouts, and pits. The one-dimension (1-D) image profile technique, in which the 1-D projection of the NMR signal of a selected slice of the intact fruit is recorded, is suitable for detecting tissue breakdown regions, presence of pits, and other defects in fruits. The oil and sugar content of fruits can be determined from the single-pulse FID spectrum measurement, in which a surface coil is used to acquire the FID spectrum and the ratio of the resonance peaks is used as the quality index. The latter two techniques are suitable for high-speed sorting of fruits. The most important accomplishment is the successful development of high-speed NMR techniques for determining internal quality of fruits while they are moving at speed up to 30 cm/s. This accomplishment is an important step toward the development of NMR techniques for on-line sorting of fruits and vegetables.
Internal Quality Evaluation and Age Identification of Fresh Korean Ginseng using Magnetic Resonance Imaging
