Some Postharvest Beneficial Effects of Irrigation with Wastewater in Tomato Fruits (Solanum lycopersicon L.)

Wastewater has been used for irrigating crops as an alternative to water scarcity. However, the effects of using this type of water have been lightly studied, so the objective of this work was to evaluate some postharvest changes and quality parameters in tomato fruits grown using two substrates: inert substrate or soil, and irrigated with two types of water: wastewater or potable water. Turning tomatoes (third grade according 1991 USDA color classification) were stored for 30 d under the following conditions: 20 °C, 56% RH or 10 °C, 84% RH. Titratable acidity, pH, weight loss, firmness, TSS content (°BX), and color (hue) were evaluated every 5 days. Data were statistically analyzed following a completely random design in factorial arrangement. Taking into account the type of irrigation water factor only, using wastewater fruits showed significantly lower and higher acidity and pH, respectively, compared to fruits from plants irrigated with potable water. However, irrigating with wastewater caused a significant increase in weight loss. Firmness loss, red color and TSS content development were not affected by the irrigating water factor. Taking into account the type of substrate factor only, growing under inert substrate condition, in general, firmness loss and TSS content were significantly reduced and increased, respectively, than growing under soil conditions. However, inert substrate growing conditions limited the tomato color red development (the hue data were significantly higher) compared to tomatoes grown under soil conditions. Weight loss, pH and titratable acidity were variables not affected by the substrate condition factor. In relation to the storage temperature factor only, storing at 20 °C, 56% RH, improved the tomato red color and TSS content development, besides, this storage conditions increased and reduced, respectively the pH and titratable acidity of fruits, compared to fruits stored at 10 °C, 84% RH. However, storing under these conditions significantly reduced fruit weight and firmness losses.