Determination of tomato quality attributes using near infrared spectroscopy and reference analysis

Abstract

© 2016, Lithuanian Institute of Agriculture. All rights reserved. The research objective was determination of ripening attributes of intact tomato (Lycopersicon esculentum Mill.) cv. ‘Rutuliai’ using near infrared (NIR) spectroscopy and reference analysis. Tomatoes were picked at six different ripening stages in order to evaluate the correlation between data obtained by near infrared spectra and physical-chemical analyses and how the quality parameters change during ripening. Primarily, spectroscopic measurements were followed by chemical analyses. NIR spectroscopy measurements and reference analyses showed that tomato fruit had lost skin and flesh firmness during the ripening processes and there were no big differences between the methods used for the determination of dry matter and soluble solids (°Brix) and the obtained results varied slightly. The obtained results of dry matter, soluble solids content (°Brix) and fruit skin and flesh firmness were presented as simple linear regression between NIR spectroscopy and reference analyses. A high correlation between NIR spectroscopy and reference analyses of dry matter was established and this correlation, expressed by regression coefficient, reached 0.9089. Regression coefficient between NIR spectroscopy and reference analyses of soluble solids was 0.815. Meanwhile, the highest correlation was detected for tomato fruit skin and flesh firmness and regression coefficient, respectively, reached 0.9119 and 0.9624. Hence the near infrared calibration has the potential to estimate the physical-chemical properties of tomato fruit according to their infrared spectra.