Effects of Irrigation with Desalinated Seawater and Hydroponic System on Tomato Quality

Abstract

The use of desalinated seawater (DSW) as an alternative to conventional water resources is gradually gaining more interest due to the strong water deficit and increasing pressure on water resources in semi-arid regions. Furthermore, the combination of this alternative irrigation with the hydroponic cultivation system would allow continuous production almost through the whole year and hydroponic-related high crop yield. Nevertheless, the effects of DSW irrigation in hydroponic systems on the product quality need to be firstly studied to avoid product quality losses. In this study, we evaluated the effects on the quality of two tomato cvs. (Ramyle and Racymo) of three different irrigation treatments (T1, DSW; T2, DSW/well water mix; and T3, well water) under hydroponic or traditional cultivation systems. The soluble solid content of samples (highly correlated to dry matter content) grown under hydroponic conditions and T3 irrigation showed the highest values (5.8 °Brix) although such differences (<0.6 °Brix) with T1 might not be sensorially appreciated. Similarly, although T3 samples showed higher acidity than T1 samples, such differences (0.06%) would be not appreciated by the consumer. Tomatoes grown in hydroponic conditions had 1.1–1.2-fold higher firmness than conventional soil conditions showing hydroponic T3 samples had the highest value (21–23 N). Tomato cv. Racymo displayed higher color index (chroma) than cv. Ramyle, registering hydroponic T1 samples the most intense red color correlated with the highest lycopene content of 41.1 mg/kg. T1 irrigation of tomatoes cv. Ramyle did not induce significant changes while differences lower than 10% were observed in the tomato cv. Racymo. The highest total antioxidant capacity, which was highly correlated to the total phenolic content (R2 = 0.80), was found for hydroponic T1 samples with 1637/1243 µmol/kg for the tomato cvs. Ramyle/Racymo. Conclusively, the use of DSW would not compromise the consumer acceptance of tomatoes due to the low (not appreciable) quality differences, with even the total antioxidant capacity of these samples being increased. Furthermore, the mix of DSW with conventional water resources (lower cost) would not compromise the tomato quality.

Active Cardboard Packaging With Encapsulated Essential Oils for Enhancing the Shelf Life of Fruit and Vegetables

“…Dry matter content (%) was also monitored for lettuce as a good-quality index of solids changes (sugars and organic acids) during storage. Dry matter was determined by drying of lettuce heads within a forced air oven at 60°C until constant weight ( 31 ). The same procedure was used to determine the water content of the rachis of grape clusters to study the rachis dehydration of grape clusters during storage.…”

Active Paper Sheets Including Nanoencapsulated Essential Oils: A Green Packaging Technique to Control Ethylene Production and Maintain Quality in Fresh Horticultural Products—A Case Study on Flat Peaches

“…The Folin–Ciocalteu reagent method was used to analyze the total phenolic content, as previously described [ 33 ]. Briefly, 19 μL of the previous extract was placed on a flat-bottom polystyrene (PS) 96-well plate and 29 μL of 1 N Folin–Ciocalteu reagent was added.…”

“…Total antioxidant capacity was determined using the free radical 2.2-Diphenyl-l-pict3,1hydrazyl (DPPH ● ) [ 36 ]. Total antioxidant capacity determination of extracts was conducted as previously described [ 33 ]. Briefly, a solution of 0.7 mM DPPH was prepared in methanol for 2 h before the assay and adjusted to 1.10 ± 0.02 nm immediately before use.…”

Quality and safety evaluation of new tomato cultivars

“…where Abs is the absorbance reading, MW is the molecular weight, 2.7 refers to the volume (in mL) of the hexane phase, w is the sample weight, and E is the molar extinction coefficient of lycopene in hexane (185.3 mM/cm). Results were expressed as mg/kg of lycopene (fresh weight, FW) (Antolinos et al, 2020).…”

“…Therefore, these are used in quality and safety assessment. These compounds are biosynthesized and accumulated in fruits, and their content is influenced by environmental factors, cultural practices, and genetic aspects, such as different cultivars (Antolinos et al, 2020). In this respect, pH and SSC were evaluated in the examined samples, and the results are reported in Figure 1.…”