Study on the water content measurement of tomatoes by near infrared technique

Abstract

Near infrared (NIR) spectroscopy is a promising technique for nondestructive measurement of farm products quality measurement and information acquisition. The objective of this research was to study the potential of NIR diffuse reflectance spectroscopy as a way for nondestructive measurement of the water content of tomato leaves. A total of 120 leaves were collected as experimental materials, 80 of them were used to form a calibration data set. In order to set up a calibration model, NIR spectral data were collected in the spectral region between 800 nm and 2500 nm by NIR spectrometer of Nicolet Corporation, and water content of tomato leaves by a drying chest, four different mathematical treatments were used in spectrums processing: different wavelength range, baseline correction, smoothing, first and second derivative. Depending on data preprocessing and PLS analysis, we can get best prediction model when we select original spectra by baseline correction at full wavelength range (800-2500nm), the best model of water content has a root mean square error of prediction (RMSEP) of 1.91, a root mean square error of calibration (RMSEC) of 0.731 and a calibration correlation coefficient (R) value of 0.96265. It is conclude that the FTNIR method with Smart Near-IR UpDRIFT accessory can accurate estimate the water content in tomato leaves.