Evaluation of internal quality of dried ginseng roots using low field NMR

This paper describes a nondestructive approach to the evaluation of internal quality of ginseng. Dried ginseng samples were tested for specific gravity, and graded based on a 4-grade scale. The nuclear magnetic resonance (NMR) properties measured by NMR parameters such as spin-lattice relaxation time (T1), spin-spin relaxation time (T2) and free induction decay (FID) amplitude were determined using the low field proton NMR analyzer. The relationships between the quality parameters (specific gravity and grade) and NMR parameters were analyzed using linear regression and neural network methods. It was found that all the NMR parameters were highly related to the quality parameters. Both the linear regression and neural network models can be used for estimation of specific gravity and grading of ginseng, however, the neural network model was preferred because of its higher estimation accuracy and superior capability of utilizing multivariate information.