Effect of Pre-harvest Periods by Replacing Nutrient Solution with Tap Water on Nitrate and Quality in Hydroponic Lettuce
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Abstract
Lettuce (Lactuca sativa L.) is a high-value nutritional food for human consumption, rich in minerals and vitamins. However, people are still concerned about the residues of nitrate content in hydroponic lettuce. Pre-harvesting by replacing nutrient solution with tap water is one of several factors that can help to reduce nitrate content and improve the quality of hydroponic lettuce. Therefore, this study focused on the effect of pre-harvest periods by replacing nutrient solution with tap water on nitrate and quality in hydroponic lettuce. This experiment was performed by replacing nutrient solution with tap water in a hydroponic system for 0 h, 24 h, 48 h, and 72 h before harvesting the lettuce product. Nitrate, vitamin C, phenolic, and soluble sugar contents were determined. The results showed that nitrate content was lowest under pre-harvest conditions for 72 h (19 mg/g dry weight, 63% reduction), but it was not significantly different for 48 h (20 mg/g dry weight, 61% reduction). The vitamin C content was significantly decreased after pre-harvesting for 72 h (5.3 µg/100 g, 30% reduction). The soluble sugar content was significantly increased and reached its highest content after pre-harvest for 48 h (3.3 mg/100 g, 105% increase), but there was no significant difference at 72 h (3.2 mg/100 g, 98% increase). Although the phenolic content decreased slightly, there was no significant difference among the treatments. In conclusion, nitrate contents were reduced the lowest, and soluble sugar contents were increased the highest after pre-harvest for 48 h. Vitamin C and phenolic contents were slightly decreased after pre-harvest periods by replacing the nutrient solution with tap water.
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References
Weller, D.L.; Saylor, L.; Turkon, P. Total coliform and generic E. coli levels, and salmonella presence in eight experimental aquaponics and hydroponics systems: A brief report highlighting exploratory data. Horticulturae 2020, 6, 42, https://doi.org/10.3390/horticulturae6030042.
Aćamović-Djoković, G.; Pavlović, R.; Mladenović, J.; Djurić, M. Vitamin C content of different types of lettuce varieties. Acta Agric. Serbica 2011, 17, 83–89.
Hmelak Gorenjak, A. Nitrate in vegetables and their impact on human health. A review. Acta Aliment. 2013, 42(2), 158–172, https://doi.org/10.1556/AAlim.42.2013.2.4.
The nitrate content in some green leafy vegetables with different cultivation methods in Thailand | Thai journal of public health available online: https://he02.tci-thaijo.org/index.php/jph/article/view/133167 (accessed on 21 February 2023).
Bell, R.; Davies, R.; Howard, E. The changing structure of food retailing in europe: The implications for strategy. Long Range Plann. 1997, 30, 853–861, https://doi.org/10.1016/S0024-6301(97)00071-X.
Htwe, N.M.P.S.; Ruangrak, E. A review of sensing, uptake, and environmental factors influencing nitrate accumulation in crops. J. Plant Nutr. 2021, 44, 1054–1065, https://doi.org/10.1080/01904167.2021.1871757.
Stitt, M. Nitrate regulation of metabolism and growth. Curr. Opin. Plant Biol. 1999, 2, 178–186, https://doi.org/10.1016/S1369-5266(99)80033-8.
Qiu, W.; Wang, Z.; Huang, C.; Chen, B.; Yang, R. Nitrate accumulation in leafy vegetables and its relationship with water. J. Soil Sci. Plant Nutr. 2014, 14, 761–768, https://doi.org/10.4067/S0718-95162014005000061.
Gil, M.I. Preharvest factors and fresh-cut quality of leafy vegetables. Acta Hortic. 2016, 57–64, https://doi.org/10.17660/ActaHortic.2016.1141.6.
Hooks, T.; Sun, L.; Kong, Y.; Masabni, J.; Niu, G. Short-term pre-harvest supplemental lighting with different light emitting diodes improves greenhouse lettuce quality. Horticulturae 2022, 8, 435, https://doi.org/10.3390/horticulturae8050435.
Tyagi, D. Impact of pre-harvest environmental gactors on the survival of enterohemorrhagic E. coli and salmonella on lettuce. Degree of Master of Science, North Dakota State University of Agriculture and Applied Science, Fargo, Noth Dakota, America, November 2014.
Zukauskas, A.; Bliznikas, Z.; Breivė, K.; Novičkovas, A.; Samuolienė, G.; Urbonavičiūtė, A.; Brazaitytė, A.; Jankauskienė, J.; Duchovskis, P. Effect of supplementary pre-harvest LED lighting on the antioxidant properties of lettuce cultivars. Acta Hortic. 2011, 87–90, https://doi.org/10.17660/ActaHortic.2011.907.8.
Zhou, W.; Wenke, L.; Qichang, Y. Reducing nitrate content in lettuce by pre-harvest continuous light delivered by red and blue light-emitting diodes. J. Plant Nutr. 2013, 36, https://doi.org/10.1080/01904167.2012.748069.
Lastra, O.C. Derivative spectrophotometric determination of nitrate in plant issue. J. AOAC Int. 2003, 86, 1101–1105, https://doi.org/10.1093/jaoac/86.6.1101.
Min, Q.; Marcelis, L.F.M.; Nicole, C.C.S.; Woltering, E.J. High light intensity applied shortly before harvest improves lettuce nutritional quality and extends the shelf life. Front. Plant Sci. 2021, 12, 615355, https://doi.org/10.3389/fpls.2021.615355.
Vàsquez, H.; Ouhibi, C.; Lizzi, Y.; Azzouz, N.; Forges, M.; Bardin, M.; Nicot, P.; Urban, L.; Aarrouf, J. Pre-harvest hormetic doses of UV-C radiation can decrease susceptibility of lettuce leaves (Lactuca Sativa L.) to botrytis cinerea L. Sci. Hortic. 2017, 222, 32–39, https://doi.org/10.1016/j.scienta.2017.04.017.
Woltering, E.J.; Witkowska, I.M. Effects of pre- and postharvest lighting on quality and shelf life of fresh-out lettuce. Acta Hortic. 2016, 357–366, https://doi.org/10.17660/ActaHortic.2016.1134.47.
Sirinupong, M. Practical for Soilless Culture in Thailand; 4th ed.; Flam-up Design Press, Bangkok, Thailand, 2017, 43-62.
Lastra, O.C. Derivative spectrophotometric determination of nitrate in plant tissue. J. AOAC Int. 2003, 86, 1101–1105.
Yemm, E.W.; Willis, A.J. The estimation of carbohydrates in plant extracts by anthrone. Biochem. J. 1954, 57, 508–514, https://doi.org/10.1042/bj0570508.
Jagota, S.K.; Dani, H.M. A new colorimetric technique for the estimation of vitamin C using folin phenol reagent. Anal. Biochem. 1982, 127, 178–182, https://doi.org/10.1016/0003-2697(82)90162-2.
Singleton, V.L.; Orthofer, R.; Lamuela-Raventós, R.M. Analysis of total phenols and other oxidation substrates and antioxidants by means of folin-ciocalteu reagent. Methods Enzymol. 1999, https://doi.org/10.1016/s0076-6879(99)99017-1.
Dicko, M.H.; Hilhorst, R.; Gruppen, H.; Traore, A.S.; Laane, C.; van Berkel, W.J.H.; Voragen, A.G.J. Comparison of content in phenolic compounds, polyphenol oxidase, and peroxidase in grains of fifty sorghum varieties from burkina faso. J. Agric. Food Chem. 2002, 50, 3780–3788, https://doi.org/10.1021/jf011642o.
Eldeen, I.M.S.; Seow, E.-M.; Abdullah, R.; Sulaiman, S.F. In vitro antibacterial, antioxidant, total phenolic contents and anti-HIV-1 reverse transcriptase activities of extracts of seven phyllanthus sp. South Afr. J. Bot. 2011, 77, 75–79, https://doi.org/10.1016/j.sajb.2010.05.009.
Guffanti, D.; Cocetta, G.; Franchetti, B.M.; Ferrante, A. The effect of flushing on the nitrate content and postharvest quality of lettuce (Lactuca Sativa L. Var. Acephala) and rocket (Eruca Sativa Mill.) grown in a vertical farm. Horticulturae 2022, 8, 604, https://doi.org/10.3390/horticulturae8070604.
Sanz-Luque, E.; Chamizo-Ampudia, A.; Llamas, A.; Galvan, A.; Fernandez, E. Understanding nitrate assimilation and its regulation in microalgae. Front. Plant Sci. 2015, 6, 899, https://doi.org/10.3389/fpls.2015.00899.
Cometti, N.N.; Martins, M.Q.; Bremenkamp, C.A.; Nunes, J.A. Nitrate concentration in lettuce leaves depending on photosynthetic photon flux and nitrate concentration in the nutrient solution. Hortic. Bras. 2011, 29, 548–553, https://doi.org/10.1590/S0102-05362011000400018.
Rosado-Souza, L.; Fernie, A.R.; Aarabi, F. Ascorbate and thiamin: metabolic modulators in plant acclimation responses. Plants 2020, 9, 101, https://doi.org/10.3390/plants9010101.
Paciolla, C.; Fortunato, S.; Dipierro, N.; Paradiso, A.; De Leonardis, S.; Mastropasqua, L.; de Pinto, M.C. Vitamin C in plants: from functions to biofortification. Antioxidants 2019, 8, 519, https://doi.org/10.3390/antiox8110519.
Wang, W.; Zhang, C.; Shang, M.; Lv, H.; Liang, B.; Li, J.; Zhou, W. Hydrogen peroxide regulates the biosynthesis of phenolic compounds and antioxidant quality enhancement in lettuce under low nitrogen condition. Food Chem. X 2022, 16, 100481, https://doi.org/10.1016/j.fochx.2022.100481.
Rosa, M.; Prado, C.; Podazza, G.; Interdonato, R.; González, J.A.; Hilal, M.; Prado, F.E. Soluble sugars-metabolism, sensing and abiotic stress. Plant Signal. Behav. 2009, 4, 388–393.