JIA-2019-11

2650 WANG Hao et al. Journal of Integrative Agriculture 2019, 18(11): 2644–2651 The moisture content of corn is affected by storage time and temperature (Song et al . 1992; Gong et al . 2010), and so is the moisture loss in freshly harvested corn during storage. During the earlier stages of storage, fresh corn is still maturing. Therefore, the relative proportion of water in the bound form increases. With the increase in storage days, the loss of moisture through the skin of grain is less than that through the cobs. Water mostly transfers to cobs and then to shucks, and then lost. These results are consistent with those reported by Song (2007). Our results suggest that the presence of shucks accelerate moisture loss of fresh ear corn. Overall, our results characterized the quantity and nature of kernel moisture and related them to the physiology, physio-chemical properties, and quality of fresh ear corn. This research reveals that NMR and MRI are useful tools for the determination of moisture distribution, migration, and loss in fresh ear corn, and thus real-time and non- destructively assess the quality of fresh ear corn during storage. All these information can be used to design the storage and processing conditions for fresh ear corn in the future. 4. Conclusion The results showed that with increase in storage time, water loss was greater than water migration in fresh ear corn within the first hour of storage; thereafter, water loss was weaker than water migration. With the extension of storage time, the signal intensity of MRI in different parts of fresh ear corn showed a downward trend, and the rate of signal intensity reduction was significantly higher in the peripheral area than at the central part of fresh ear corn. In addition, the relative proportion of bound water increased with a concomitant drop in that of free water, when the total water content reduced in fresh ear corn under storage. These results characterized a a b c d e f a b b c d e e a b c d e f g 0 500 000 1 000 000 1 500 000 2 000 000 0 2 4 6 8 Signal intensity Time (d) Bound water Free water Total water e d c c b a a 50 60 70 80 90 100 110 0 2 4 6 8 Bound water percentage (%) Time (d) Fig. 5 Relative proportion of bound and free water in fresh ear corn at different storage time. Means of free water, bound water, total water, and bound water percentage, respectively, followed by the same letter are not significantly different at P =0.05 according to the Fisher’s protected least significant difference test. Fig. 6 Grayscale map of the same section of fresh ear corn at different storage time during one-week storage.