Does drought increase the antioxidant nutrient capacity of tomatoes?

Tomato fruit has long been regarded as a valuable functional food due to its potential role in the prevention of chronic diseases and thus its positive impacts on human health. In this study, the effect of drought under the climate change threat on increasing antioxidant enzyme activities and non-enzymatic antioxidants in terms of functional food properties of tomato fruits was investigated. Nine drought-tolerant tomato genotypes and two commercial cultivars were grown in an open field that was well watered and exposed to drought stress conditions. The biochemical effects of drought stress in fruit were determined by evaluating the fruits' contents of lipid peroxidation, vitamin C (L-ascorbic acid), total phenols, total flavonoids, lycopene, and beta-carotene and the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR), total soluble solids and pH. Significant differences (P < 0.05) were found between tomato genotypes in the antioxidant capacity. Antioxidants such as vitamin C, total phenolics, flavonoids, TSS and beta-carotene increased, in tomato fruit under drought. However, pH was slightly decreased. A slight increase in lycopene was observed. The activities of the antioxidative enzymes SOD, CAT, APX and GR were significantly increased in tomato fruit under drought. The increased antioxidant capacity of drought-tolerant tomatoes has been found promising in terms of human nutrition under the threat of climate change.