Flavour quality of organic tomatoes grown in different systems

Abstract

Tomatoes were grown organically in a greenhouse in soil in an open system (control), on compost beds in a confined system and on compost beds with holes for root penetration in a combined system. Tomatoes were harvested in the spring (May) and in the autumn (October) at comparable maturity and analysed, for flavour compounds and sensory quality. A total of 31 volatile compounds were collected from blended tomatoes using a dynamic headspace technique and identified and quantified by GC and GC-MS. The aroma profile of organically grown tomatoes was in agreement with published data on conventional tomatoes. The content of volatiles, soluble solids, citric acid and dry matter was almost the same regardless of growing system. Sensory analysis revealed that tomatoes harvested in the spring from the confined system scored higher in tomato flavour and sourness than those from the combined system. In the autumn there was no effect of growing system on sweetness, sourness and tomato flavour but on the content of hexanal, ( Z )-3-hexenal and ( Z )-3-hexen-1-ol. Principal components analysis (PCA) revealed that system accounted for 15% and harvest time for 67% of the variation in the volatile data indicating that growing system had only a minor effect on the chemical composition and sensory quality of tomatoes harvested at comparable maturity. Growers of organic tomatoes can therefore switch to a confined or combined growing system without affecting the flavour quality of tomatoes.