Development of a nondestructive measurement system for mango fruit using near infrared spectroscopy

Near infrared spectroscopy has been widely used for the evaluation of chemical components in food and agricultural products. In this study, a portable near infrared (NIR) spectrometer was developed to simultaneously evaluate the internal and external quality of tropical fruits. Mango fruits are grown in the southern part of Japan and have high economic value. In this region, sorting facilities are used to check the internal quality of each mango. However, most of the product is directly shipped to consumers, complicating quality assurance procedures. A portable NIR spectrometer is an affordable method for farmers to evaluate the internal and external quality of fruits. In this study, the soluble solid content (SSC) and skin color of mangoes (Mangifera indica L. cv. Irwin) were investigated using a portable NIR spectrometer. Calibration equations for SSC and skin color were developed using a partial least squares regression. The calibrations had a correlation coefficient of 0.90-0.95 in a wavelength range of 580–970 nm. Results showed that a portable NIR spectrometer is a useful and effective instrument to nondestructively analyze sugar content (as indicated by SSC) and skin color in mangoes.