Analysis of organic acid content in cultivars of tomato harvested in Tenerife

The determination of organic acids in tomato samples was optimized using the HPLC method with on-line photodiode array detection, previous to extraction with 80% ethanol at room temperature and clean-up in Accell Plus QMA cartridge. The organic acids (oxalic, pyruvic, malic, citric, fumaric and ascorbic), Brix degree, acidity and pH were determined in five tomato cultivars (Dorothy, Boludo, Dominique, Thomas and Dunkan) harvested in Tenerife. There are several significant differences among cultivars in the concentration of many acids. The cultivation method, sampling period and the region of production were also considered. Citric, malic and oxalic acids were the major organic acids in all the cultivars. Some significant differences in the studied parameters were observed between the cultivars. The cultivation method and sampling period influenced in a variable way the studied parameters, depending on the tomato cultivar. The production region influenced the ascorbic acid concentration of the tomatoes. Applying stepwise discriminant analysis, it was found that the sampling period is more important in the differentiation of the tomato samples than the cultivar, cultivation method and production region.