The hypothesis that tomato fruits from organic farming and greater stressing conditions associated with organic farming leads to more nutritional compounds, such as phenolics and vitamin C, recently got tested.
The research report on tomatoes (Solanum lycopersicum) obtained from the northeastern part of Brazil compared the weights and biochemical properties of tomatoes from organic and conventional farms. Growing conditions were reported by the farmers. The researchers found that tomatoes grown on organic farms were approximately 40% smaller than those grown by conventional techniques but they accumulated more compounds linked to stress resistance, along with higher concentrations of sugars and vitamin C. Cell membrane lipid peroxidation (LPO) degree was 60% higher in organic tomatoes.
Titratable acidity was 29% greater at the stage of commercial maturity, while soluble solids content was 57% greater and the concentrations in vitamin C were 55% higher.
According to the authors, organic farming exposes plants to greater stress than conventional farming and they suggest that this increased stress may be the reason organic tomatoes had those higher levels of sugars, vitamin C and pigment molecules like lycopene, an anti-oxidant compound – all of which are associated with the biological response to stress.
Based on these observations, the authors suggest that growing strategies for fruits and vegetables should aim to balance plant stress with efforts to maximize yield and fruit size, rather than trying to eliminate stress to increase yields.
Citation: Oliveira AB, Moura CFH, Gomes-Filho E, Marco CA, Urban L, et al. (2013) The Impact of Organic Farming on Quality of Tomatoes Is Associated to Increased Oxidative Stress during Fruit Development. PLoS ONE 8(2): e56354. doi:10.1371/journal.pone.0056354