DETERMINATION OF °BRIX, LYCOPENE, β-CAROTENE AND TOTAL CAROTENOID CONTENT OF PROCESSING TOMATOES USING NEAR INFRARED SPECTROSCOPY

The use of near infrared spectroscopy to measure the content of °Brix and carotenoids of tomatoes was investigated. One hundred and twenty tomato samples were produced at the Horticulture Department in Gödöllő (Hungary). The samples were analyzed by HPLC and digital refractometer and scanned with a diode array Perten DA7200 NIR Analyzer (950-1.650 nm). The calibration was based on partial least squares regression with cross-validation. The performance of the final model was evaluated according to root mean square error of cross validation (RMSECV), root mean square error of estimation (RMSEE) and the determination coefficient (R²). The spectral information sufficiently correlated with the results of HPLC determination. The results indicate that β-carotene content was accurately predicted [R² = 71.10; root mean square error of cross-validation (RMSECV) = 0.46 μg/g]. Lycopene content was better predicted (R² = 91.75, RMSECV = 1.28 mg/100 g) and the prediction of the total carotenoid content was also acceptable (R² = 87.24, RMSECV = 5.36 μg/g).