Sensory analysis, sugar and acid content and consumer acceptance of two types of tomato varieties hydroponically grown and effected by EC value 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 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 panellist and by an acceptance test with consumers. Furthermore, contents of reducing sugars and titratable acid of fruits were analysed. To find explanations for consumer preferences relationships between results of quantitative descriptive analysis, consumer acceptance test and inner compounds 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 bitter 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.
Consumers preferred the flavour from both cultivars of those fruits, which were cultivated at EC 3.5 dS m-1. Acceptance in the characteristics flavour, aftertaste and mouthfeel of fruits of the longlife cultivar grown at EC 6.0 dS m-1 was diminished.
There were significant correlations between the results of the hedonic consumer assessment of the products and the quantitative descriptive analysis, which could contribute to explain preferences. In most cases the sensory changes caused by increasing nutrient solution EC from 1.0 dS m-1 to 6.0 dS m-1 improved the quality of the conventional round cultivar but not that of the longlife one.
Auerswald, H.; Schwarz, D.; Kornelson, C.; Krumbein, A., Brückner; B. 1999. Sensory analysis (QDA), sugar and acid content and consumer acceptance of two types of tomato varieties hydroponically grown and effected by EC value of the nutrient solution. Scientia Horticulturae, 82 (3/4), 227-242.