Non-Destructive Quality Measurement Using Visible Near-Infrared Spectroscopy for Determining Soluble Solid and Lycopene Content in Cherry Tomatoes

Abstract

　The quality of the pulp and flesh of fruits and vegetables is a key determinant of their commercial value. In the case of tomatoes, sugar content is an important index of their quality; they also contain lycopene, which has proven health benefits. To preserve these components, non-destructive methods to evaluate the quality of tomatoes are required. For large- and medium-sized tomatoes, this can be achieved using visible near-infrared spectroscopy. To date, however, no calibration curves have been developed for non-destructive measurement of sugar and lycopene content of many different cherry (mini) tomatoes. In this study, we developed a non-destructive method to conduct rapid and simultaneous measurements of sugar and lycopene content in cherry tomatoes, and subsequently generated high-precision calibration curves that were incorporated into an existing measuring instrument. The correlation coefficients of the sugar and lycopene content were 0.97 and 0.96, respectively. Measurement of sugar and lycopene content of many different cherry tomatoes, regardless of their shape, color, and size, was conducted using the calibration curves, and the results were not influenced by the temperature of the fruit. The results of this study suggest that non-destructive methods can be applied to measure sugar and lycopene content of cherry tomatoes, and these methods will contribute to the branding and sale of these tomatoes.