Nondestructive Analysis of Sugar Content on Watermelon Using MRI Device

So far, the use of superconducting magnets has been limited to chemical analysis and medical inspection. To develop a new use, we have tried to apply common MRI devices as nondestructive sugar content detector of watermelon. To estimate the sugar content, a new technique using multiple regression analysis of two NMR relaxation times was developed. It was found that the coefficient of multiple regression at the center of the watermelon exceeded 0.9 and the standard error of prediction was around 0.5, and that the over-ripened part of flesh called ‘nieka’ in watermelon could be distinguished because its T2 was much longer than that of the oridinary part. An evaluation rate of sugar content could be below 6s per watermelon. It is concluded that multiple analysis of T1 and T2 on intact watermelon can be applied as a non-invasive, nondestructive indicator of sugar content.