NONDESTRUCTIVE SUGAR CONTENT MEASUREMENTS OF INTACT FRUIT USING SPIN-SPIN RELAXATION-TIME (T(2)) MEASUREMENTS BY PULSED H-13 MAGNETIC-RESONANCE

A technique to estimate sugar content of intact fruit using 10 MHz pul sed proton magnetic resonance (H-1-MR) was investigated. The values of spin-spin relaxation times (T2) were calculated from the data. A corr elation model between T2 values and sugar contents was developed from the principle of chemical exchange between sugar and water protons. Th e chemical exchange between sugar and water changed the values of T2. The correlation model was verified by experiments on intact fruit. The T2 of intact grapes and sweet cherries were correlated with soluble s olids as measured with a refractometer. These results suggest that T2 measurements on intact fruit can be used as a rapid, noninvasive and n ondestructive indicator of sugar content.