## 3 Results and Discussion
The quality of the tomato fruits was evaluated taking into account some organoleptic properties (firmness, acidity or total soluble solids), the antioxidant status (lycopene, \(\beta\) caroten, polyphenols, antioxidant activity), the proximate composition (crude lipid, protein, fibre, dietary fibre, calorific value), the antinutritional composition (phytate, tannins, oxalate, saponins, trypsin inhibitor, \(\alpha\)-amylase inhibitor) and the mineral content (K, Ca, Mg, Fe, Zn, Na). Firmness is an important quality parameter in terms of storage, consumer acceptance and transportation of tomato fruits. The results of our experiment regarding the firmness of tomato fruits varied from 3.45 kg\(\cdot\)cm\({}^{-2}\) for T1 to 4.93 kg\(\cdot\)cm\({}^{-2}\) for C, significant differences being registered between these treatments. For the rest of the treatments the electric current applied to tomato plants did not significantly influence the firmness of the tomato fruits as compared to the control. A reduction in firmness is usually associated with the dissociation of middle lamella and production of a variety of enzymes which affect the cell wall integrity [49; 50]. In our experiment it was observed that the application of the lowest electric current (T1--0.15 A) decreased the most the firmness of tomato fruits. However, the differences between T1 and the rest of the treatments with electric current were not significant. In comparison with other studies which showed a decrease in the firmness along with an increase in the electric treatment intensity [51; 52], the application of 0.30 A (T2); 0.45 A (T3) or 1.5 V (T4 and T5) did not affect the firmness of tomato fruits. Regarding the influence of the treatments applied to the plants on the acidity of tomato fruits, results ranged from 0.4 g citric acid\(\cdot\)100 g\({}^{-1}\) f.w. (T5), to 0.55 g citric acid\(\cdot\)100 g\({}^{-1}\) f.w. (T3) (Table 4). A significant higher acidity of the fruits as compared with the control (0.44 g citric acid\(\cdot\)100 g\({}^{-1}\) f.w.) was registered for T3 (0.55 g citric acid\(\cdot\)100 g\({}^{-1}\) f.w. ), T1 and T2 (both of 0.53 g citric acid\(\cdot\)100 g\({}^{-1}\) f.w. ), while for T4 and T5 the acidity was almost the same as in the case of the control. According to [PERSON] et al., [53], the acidity of tomato fruits can be used as an indicator of maturity, as the content of acids decrease along with the ripening of the fruits. During the ripening of tomato fruits, citric acid is the one that last disappear [54]. Therefore, the lower the value of citric acid, ripen the tomato. This suggest that in our experiment, at the time of harvest, the tomatoes fruits of T4 and T5 were better ripen than the rest of the fruits belonging to the plants subjected to the electric current treatments. Figure 2: Chlorophyll content index from tomato plant (T1—0.15 A; T2—0.30 A; T3—0.45 A; T4— polarity; T5—soil version; C—Control; ns-nonsignificant). The results of total soluble solids showed that the electric current applied to tomato plants did not influence the amount of total soluble solids, the registered values being not significantly different as compared with the control, except the plants subjected to 1.5 V where one syringe needle was inserted in the apical area and another at the base of the stem (T4) for which a significant decrease in the total soluble solids was recorded (Table 4). The lack of differences between the treated plant and the control can suggest that the electric current intensities used in the experiment did not affect the cell activity or metabolism. In other experiments where electric current pulses were applied to tomato plants, the increase in the total soluble solids content was linked to various causes: (1) osmotic imbalance, which led to the accumulation of sugars in order to restore the cell activity, (2) acceleration of ripening as a result of increased metabolic activity, (3) disarrangements of the polysaccharides and molecular bonds found in the cell wall [52].