Composition and taste of tomatoes as affected by increased salinity and different salinity sources

Tomato plants were grown in rockwool slabs under glasshouse conditions at different salinities (3-9 mS cm(-1)) to improve the taste of tomato fruit without reducing their quality in other respects. NaCl or different combinations of major nutrients (comprising Na, K, Ca, Mg, Cl, NO3-N, P and SO4-S) were applied as salinity sources. Increased salinity in the root zone increased the concentrations of dry matter, sugars, titratable acid, vitamin C and total carotene in the tomato fruit, and were in all cases but one independent of salinity source. On a per-fruit basis, no differences in glucose or fructose were found whereas the content of tritratable acid and dry matter decreased with increased salinity. The fruit composition was slightly affected by fruit position within the truss. A trained sensory panel found that NaCl improved the sweetness of tomato fruit more than the other salinity sources. The sensory panel was not able to separate samples from the different treatments by sourness. Fruit firmness increased with increasing salinity but only for measurements on fruit with intact skin.