Determining the tomato firmness using nondestructive impact technique

In this study, it was aimed to estimate the firmness of Bandita F1 greenhouse tomatoes using the non-destructive impact technique. The study was carried out in two stages. In the first stage, the changes in color parameters and mechanical properties of tomato samples depending on the maturity stage were investigated. In the second step, nondestructive impact test was applied on tomato samples at six different maturity stages and the firmness models were developed by associating the impact parameters measured after the impact test with the skin rupture force (KYK) and skin firmness (KS), which is accepted as the reference measurement and used in the definition of firmness of tomatoes. A dynamic impact test setup was used to develop hardness estimation models. Tomato fruits were dropped from a distance of 15 mm on the aluminum impact plate connected above the force sensor. In order to develop a post-impact firmness estimation model, nondestructive impact parameters were extracted using impact force-contact time graphs. Obtained impact parameters were associated with KYK and KS, which were accepted as reference measurements. The number of impact parameters was reduced by stepwise regression analysis method. Tomato firmness estimations were made using the measured nondestructive impact parameters with the multiple linear regression analysis method. According to the results of the statistical analysis, the high correlation between the impact parameters and tomato skin firmness was found to be higher than the skin rupture force among the developed firmness estimation models. This relationship was evident in both the calibration and validation datasets. In the calibration and validation datasets, the tomato skin firmness estimation coefficients of determination (R2) were also calculated as 0.86 and 0.88, respectively.