Sensory analysis, sugar and acid content of tomato at different EC values of the nutrient solution

The influence of three concentrations of nutrient solution (electrical conductivity, EC: 1.0, 3.5 and 6.0 dS m(-1)) on the sensory properties of tomato was investigated. Two tomato cultivars representing two types-a conventional round tomato (cv. Counter) and a round longlife tomato (cv. Vanessa)-were harvested from a closed hydroponic system with recirculating nutrient solution. The same products were investigated by quantitative descriptive analysis with trained panellists and by an acceptance test with consumers. Furthermore, the contents of reducing sugars and the titratable acid of fruits were analysed. To find explanations for consumer preferences relationships between the results of quantitative descriptive analysis, consumer acceptance tests and the sugar and acid contents of the fruits were investigated. The quantitative descriptive analysis revealed changing intensities of sensory attributes of appearance, firmness by touch, flavour, aftertaste and mouthfeel with increasing nutrient solution EC. However, the change of different sensory attributes was different for the two cultivars. Intensity of unfavourable flavour attributes such as mouldy, spoiled sweetish and hitter was stronger only for the longlife cultivar when cultivated at high EC. Higher EC values resulted in higher contents of reducing sugars and titratable acid, which influenced the intensity of several sensory attributes of smell, flavour and aftertaste evaluated by the descriptive panel.