Abstract:

The aim of the study was to determine the effects of deficit irrigation and postharvest storage on nutritional composition of tomatoes. Tomato fruits (Pectomech variety) cultivated under different irrigation treatments (100% ETc, 90% ETc, 80% ETc and 70% ETc) were harvested and analyzed for moisture, ash, protein, fat, fibre, carbohydrate, calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), iron (Fe), copper (Cu) and zinc (Zn) contents. Moisture, ash, protein, fat, fibre, and carbohydrate were determined by standard AOAC methods, calcium and magnesium by EDTA titration, potassium and sodium by flame photometry, iron, copper and zinc by atomic absorption spectrophotometry. Results indicated that fat, fibre and carbohydrate increased with deficit irrigation (water stress) whilst moisture, ash, protein, calcium, magnesium, potassium, sodium, iron, copper and zinc contents decreased. Apart from fibre content which increased significantly during storage for all water treatments, all the other nutritional components (moisture, ash, protein, fat and carbohydrate) decreased significantly. Considering the percentage increases and decreases obtained for nutritional compositions of the tomatoes in this study, it can be concluded that a 10- 20% reduction in the amount or volume of water applied in the cultivation of the Pectomech tomato variety would produce tomato with optimum quality that would compensate for yield losses.

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