Determination of Dry Matter Content in Potato Tubers by Low-Field Nuclear Magnetic Resonance (LF-NMR)

The objective of this study was to develop a calibration model between time-domain low-field nuclear magnetic resonance (LF-NMR) measurements and dry matter (DM) content in single potatoes. An extensive sampling procedure was used to collect 210 potatoes from eight cultivars with a wide range in DM content, ranging from 16 to 28%. The exponential NMR relaxation curves were resolved into four mono-exponential components using a number of solution diagnostics. Partial least-squares (PLS) regression between NMR parameters (relaxation time constants T 2,1−4 and magnitudes M 0,1−4) and DM content resulted in a model with low error (RMSECV, 0.71; RMSEP, 0.60) and high correlation (r CV, 0.97; r test, 0.98) between predicted and actual DM content. Correlation between DM content and each of the proton populations revealed that M 0,1 (T 2,1, 3.6 ms; SD, 0.3 ms; r, 0.95) and M 0,4 (T 2,4, 508 ms; SD, 53 ms; r, −0.90) were the major contributors to the PLS regression model.