Application of low-field nuclear magnetic resonance and proton magnetic resonance imaging in evaluation of 'Jinxiu' yellow peach's storage suitability

In this study, changes in the transverse relaxation time (T-2), signal intensity (A(2)), and images of 'Jinxiu' yellow peach fruits were investigated using low-field nuclear magnetic resonance (LF-NMR) and proton magnetic resonance imaging (H-1-MRI). The water content, (determined using centrifuging technology), fruit firmness, and ethylene production were evaluated at 4 +/- 1 degrees C and 25 +/- 2 degrees C. The results showed a signal peak (A(2)) and T-2 at 500-1000 ms. On days 4-6, T-2 changed from 796 ms to 861 ms, and decreased with longer time at 25 degrees C. Water content also decreased and high adjusted determination coefficient (adj-R-2) values with water content were found for T-2 (R-2 = 0.95) and A(2) (R-2 = 0.99), indicating a high degree of fit for the prediction equations. A(2) decreased and T-2 shortened after prolonged storage at 4 degrees C and high adj-R-2 values were found between the water content and T-2 (R-2 = 0.93) and A(2) (R-2 = 0.97). Ethylene production and firmness were the same as for T-2, A(2), and internal breakdown at 25 degrees C for 4-6 days, and 4 degrees C for 16-21 days. Compared with storage at 25 degrees C, low temperature storage inhibited water loss and also prohibited internal breakdown. T-2 and A(2) can be used to evaluate the storage characteristics of yellow peach fruits, and the internal breakdown of pulp tissue could be clearly observed by 1H-MRI, which is a function of LF-NMR. 1H-MRI can provide high-resolution images showing the internal structure of intact peaches. Thus, LF-NMR is a new technology that could be an effective and simpler method for monitoring and predicting water content, as well as detecting quality issues during peaches storage.