Near-Infrared Monitoring of the Growth Period of Japanese Pear Fruit Based on Constituent Sugar Concentrations

Abstract

To develop nondestructive monitoring techniques in plant science, near-infrared spectroscopy (near-IRS) was applied to estimate the growth stages of the fruit of the Japanese pear tree based on the constituent sugar concentrations in the juice. Regular differences were observed among the spectra of juice from pears of different maturity, and the absorption bands of these spectra were assigned to carbohydrate. The multiple linear regression calibration equations of each constituent sugar (namely, sucrose, glucose, fructose, and sorbitol) used three to seven wavelengths as independent variables. The correlation coefficients of each sugar concentration were 0.97, 0.90, 0.99, and 0.98, with standard error of prediction values of 0.17, 0.15, 0.21, and 0.40 respectively. Results of measurement of each constituent sugar concentration in Japanese pear juice by near-IRS indicated that the sugar components changed with the growth period of fruits. Therefore, near-IRS can be used to effectively evaluate the growth s...