Changes in Selected Quality Attributes of Greenhouse Tomato Fruit as Affected by Pre- and Postharvest Environmental Conditions in Year-round Production

Abstract

<jats:p>‘Durinta’ tomatoes were grown hydroponically using rockwool substrate in greenhouses to assess the seasonal and postharvest changes of selected quality attributes including lycopene and total soluble solids (TSS, % Brix) concentrations in fruit when grown under varied electrical conductivity (EC) in the nutrient solution. Two levels of EC examined in this study were 2.4 and 4.8 dS·m<jats:sup>−1</jats:sup> for standard low EC and high EC treatments, respectively. All fruits at light-red and red ripeness stages were harvested and weighed every week, and nine fruits visually representing the median group of red fruits were selected from each EC treatment and subject to measurements of lycopene and TSS concentrations. Of 53 harvest weeks (Dec. 2005 to Dec. 2006), 45 weeks were subject to fruit quality analyses at harvest and 3 weeks were subject to postharvest quality analyses. Lycopene concentration and TSS showed seasonal differences with larger variation in lycopene, but the high EC treatment induced an overall average of 18% greater lycopene concentration and a 20% greater TSS. The regression analyses indicated that efflux solution EC (EEC) was the most influential factor for both lycopene and TSS concentrations, but secondary influential factors were greenhouse temperature for lycopene and daily light integral for TSS. Postharvest storage test showed that selected fruit quality attributes (lycopene, TSS, ascorbic acid, and total phenolics) changed minimally or not at all for 10 days when stored at 12 °C, a widely recommended tomato postharvest storage temperature. Overall, we consider that producing lycopene-rich tomato by controlling EC of nutrient solution was feasible during year-round greenhouse production using a high-wire rockwool culture system.</jats:p>

Increased Electrical Conductivity in Nutrient Solution Management Enhances Dietary and Organoleptic Qualities in Soilless Culture Tomato

“…Lycopene content was considerably enhanced (with an average growth of 6.3% between low and high EC treatment). These results are similar to those of other studies (Borghesi et al, 2011;De Pascale et al, 2001;Krauss et al, 2006;Kubota et al, 2012). However, EC reduced or had no effect on lycopene content, as previously reported (Ali and Ismail, 2014;Fern andez-García et al, 2002;Van Meulebroek et al, 2012).…”

“…Total phenolics content and total antioxidants increased, with an average growth of 8.1% and 11.1%, respectively, between the low and high EC treatments. Previous studies found significant differences at extreme EC values (2-10 dS · m -1 ) (Krauss et al, 2006;Van Meulebroek et al, 2012;Zushi and Matsuzoe, 2015) or no differences at moderate EC values (Ali and Ismail, 2014;Kubota et al, 2012). This enhancement may be a response to increased reactive oxygen species linked to water stress level (Krauss et al, 2006).…”

“…Ali and Ismail (2014) reported a 7-fold increase in ascorbic acid content in plants subjected to severe salinity stress (10 dS · m -1 ). These authors stated that specific genotype salinity sensitivity plays a key role in tomato plant behavior, and thus, contradictory results were reported (Fern andez-García et al, 2002;Kubota et al, 2012).…”

Chemical and Sensory Properties of Greenhouse Tomatoes Remain Unchanged in Response to Red, Blue, and Far Red Supplemental Light from Light-emitting Diodes

“…Reduced water status and increased soil EC can increase sugar, titratable acids, and carotenoid concentrations in tomato fruits, which may contribute to the differences observed between greenhouse and fieldgrown tomato fruits in Expt. 1 (Kubota et al, 2012;Mitchell et al, 1991;Segura et al, 2009;Wu and Kubota, 2008;Yin et al, 2010). The differences between outdoorgrown and greenhouse tomatoes, as well as the lack of differences among greenhouse treatments, corroborated our sensory data as well as previous findings (Dzakovich et al, 2015).…”

Assessment of Phytochemicals, Quality Attributes,and Antioxidant Activities in Commercial Tomato Cultivars

“…The quantity and composition of beneficial compounds present in tomato vary significantly depending on various plant specific factors and environmental conditions. Antioxidant properties of the fruit are influenced by genotype, degree of ripening, soil and climate conditions, part of the fruit, light, temperature, growing season, agricultural practices, and postharvest conditions (Kotikova et al, 2011;Oms-Oliu et al, 2011;Kubota et al, 2012;Vallverdu-Queralt et al, 2012;Tinyane et al, 2013;Kuscu et al, 2014;Vinha et al, 2014;Riga, 2015). Of these factors, genotype is one of the most important for determining the quantity of phytochemicals, and consequently for the overall quality of the tomato fruit.…”