Effect of relative humidity and light exposure on fluorescence compound dynamics, soluble solid and acidity of Japanese Citrus Iyokan during postharvest treatment

Muharfiza Muharfiza, Dimas Firmanda Al-Riza, Nie Sen, Yasushi Kohno, Tetsuhito Suzuki, Makoto Kuramoto, Yuichi Ogawa, Naoshi Kondo


The Miyauchi iyokan (iyokan) citrus fruit is typically harvested in late December to prevent damage from the winter weather. At the time of harvest, the ratio of Soluble Solids (SS) to acid content is generally low, commonly used to assess the quality of the juice. Therefore, the goal during postharvest treatment is to decrease the acid content and improve the SS levels. The quality of citrus can be influenced by environmental factors such as relative humidity (RH) and exposure to light, so it is important to monitor their effects. Hence, this study aims to observe the changes in internal quality indicators, such as the SS/acid ratio and fluorescence compounds, under different RH and light conditions to understand how the citrus characteristics are affected. The postharvest treatment involved storing the citrus fruit at temperatures between 5-10°C for two months under various conditions i.e., in the dark and exposed to light, with high RH (80-90%) and low RH (40-50%). The SS/acid ratio did not show significant changes during the two months of storage under any treatments. However, the high RH condition resulted in a slightly higher SS/acid ratio. Similarly, the Tryptophan-like compound did not exhibit any significant response to the different treatments. However, the intensity of fluorescence from polymethoxylated flavones (PMFs) was higher in the dark treatment compared to the light treatment. PMFs play various roles in signaling and defense mechanisms in plants. Additionally, there was a notable increase in PMFs after thirty days of storage, indicating a response to light-induced stress.


Fluorescence; Light; Polymethoxylated flavones; Relative humidity; SS/acid ratio

Full Text:



Albertini, M. V., Carcouet, E., Pailly, O., Gambotti, C., Luro, F., and Berti, L. (2006) ‘Changes in organic acids and sugars during early stages of development of acidic and acidless citrus fruit’, Journal of Agricultural and Food Chemistry, 54, pp. 8335–8339

Arcas, M. C., Botía, J. M., Ortuño, A. M., Río, J. A. D., Ortuño, A. M., Arcas, M. C., and Botía, J. M. (2000) ‘UV irradiation alters the levels of flavonoids involved in the defence mechanism of Citrus aurantium fruits against Penicillium digitatum’, European Journal of Plant Pathology, 106, pp. 617–622

Davis, P. L., Roe, B., and Bruemmer, J. H. (1973) ‘Biochemical changes in citrus fruits during controlled-atmosphere storage’, Journal of Food Science, 38, pp. 225–229

Dorta, E., González, M., Lobo, M. G., Sánchez-Moreno, C., and de Ancos, B. (2014) ‘Screening of phenolic compounds in by-product extracts from mangoes (Mangifera indica L.) by HPLC-ESI-QTOF-MS and multivariate analysis for use as a food ingredient’, Food Research International, 57, pp. 51–60

Echeverria, E., and Ismail, M. (1987) ‘Changes in sugars and acids of citrus fruits during storage’, Proceedings of the Florida State Horticultural Society, pp. 50–52.

El-Otmani, M., Ait-Oubahou, A., Zacarías, L. (2011) ‘21 - Citrus spp.: orange, mandarin, tangerine, clementine, grapefruit, pomelo, lemon and lime’ in Yahia, E. M. (eds.) Postharvest Biology and Technology of Tropical and Subtropical Fruits. Cambridge: Woodhead Publishing, pp. 437-516

Gaydou, E. M., Bianchini, J. P., and Randriamiharisoa, R. P. (1987) ‘Orange and mandarin peel oils differentiation using polymethoxylated flavone composition’, Journal of agricultural and food chemistry, 35, pp. 525–529

Henriod, R. E. (2006) ‘Postharvest characteristics of navel oranges following high humidity and low temperature storage and transport’, Postharvest Biology and Technology, 42, pp. 57–64

Huché-Thélier, L., Crespel, L., Gourrierec, J. L., Morel, P., Sakr, S., and Leduc, N. (2016) ‘Light signaling and plant responses to blue and UV radiations - Perspectives for applications in horticulture. Environmental and Experimental Botany, 121, pp. 22–38

Iglesias, D. J., Cercós, M., Colmenero-Flores, J. M., Naranjo, M. A., Ríos, G., Carrera, E., Ruiz-Rivero, O., Lliso, I., Morillon, R., Tadeo, F. R., and Talon, M. (2007) ‘Physiology of citrus fruiting’, Brazilian Journal of Plant Physiology, 19, pp. 333–362

Kaplan, F., Kopka, J., Haskell, D. W., Zhao, W., Schiller, K. C., Gatzke, N., Sung, D. Y., Guy, C. L. (2004) ‘Exploring the temperature-stress metabolome of arabidopsis’, Plant Physiology, 136, pp. 4159–4168

Khalifah, R. A. (1967) ‘Metabolism of DL-Tryptophan-3-14C by the fruitlets of Citrus aurantifolia’, Physiologia Plantarum, 20, pp. 355–360

Kotilainen, T., Tegelberg, R., Julkunen‐Tiitto, R., Lindfors, A., Aphalo, P. J. (2008) ‘Metabolite specific effects of solar UV-A and UV-B on alder and birch leaf phenolics’, Global Change Biology, 14, pp. 1294–1304

Koyama, K., Ikeda, H., Poudel, P. R., Goto-Yamamoto, N. (2012) ‘Light quality affects flavonoid biosynthesis in young berries of Cabernet Sauvignon grape’, Phytochemistry, 78, pp. 54–64

Kusunose, H., and Sawamura, M. (1980) ‘Ethylene production and respiration of postharvest acid citrus fruits and wase satsuma mandarin fruit’, Agricultural and Biological Chemistry, 44, pp. 1917–1922

Ladaniya, M. (2010) Citrus Fruit: Biology, Technology and Evaluation. Cambridge: Academic Press.

Lawaetz, A. J., and Stedmon, C. A. (2009) ‘Fluorescence intensity calibration using the raman scatter peak of water’, Applied Spectroscopy, 63, pp. 936–940

Li, Q., and Kubota, C. (2009) ‘Effects of supplemental light quality on growth and phytochemicals of baby leaf lettuce’, Environmental and Experimental Botany, 67, pp. 59–64

Li, S., Lo, C. Y., and Ho, C. T. (2006) ‘Hydroxylated polymethoxyflavones and methylated flavonoids in sweet orange (Citrus sinensis) peel’, Journal of Agricultural and Food Chemistry, 54, pp. 4176–4185

Matsumoto, H., and Ikoma, Y. (2012) ‘Effect of different postharvest temperatures on the accumulation of sugars, organic acids, and amino acids in the juice sacs of satsuma mandarin (Citrus unshiu Marc.) fruit’, Journal of Agricultural and Food Chemistry, 60, pp. 9900–9909

Muharfiza, Al Riza, D. F., Saito, Y., Itakura, K., Kohno, Y., Suzuki, T., Kuramoto, M., and Kondo, N. (2017) ‘Monitoring of fluorescence characteristics of satsuma mandarin (Citrus unshiu Marc.) during the maturation period’, Horticulturae, 3, pp. 1-11

Sheldrake, A. R. (1973) ‘The production of hormones in higher plants’, Biological Reviews, 48, pp. 509–559

Shi, J. X., Porat, R., Goren, R., and Goldschmidt, E. E. (2005) ‘Physiological responses of ‘Murcott’ mandarins and ‘Star Ruby’ grapefruit to anaerobic stress conditions and their relation to fruit taste, quality and emission of off-flavor volatiles’, Postharvest Biology and Technology, 38, pp. 99–105

Sun, Y., Zhang, H., Sun, Y., Zhang, Y., Liu, H., Cheng, J., Bi, S., and Zhang, H. (2010) ‘Study of interaction between protein and main active components in Citrus aurantium L. by optical spectroscopy’, Journal of Luminescence, 130, pp. 270–279

Swatsitang, P., Tucker, G., Robards, K., and Jardine, D. (2000) ‘Isolation and identification of phenolic compounds in Citrus sinensis’, Analytica Chimica Acta, 417, pp. 231–240

Taulavuori, K., Pyysalo, A., Taulavuori, E., and Tiitto, R. J. (2018) ‘Responses of phenolic acid and flavonoid synthesis to blue and blue-violet light depends on plant species’, Environmental and Experimental Botany, 150, pp. 183–187

Thabti, I., Elfalleh, W., Hannachi, H., Ferchichi, A., and Campos, M. D. G. (2012) ‘Identification and quantification of phenolic acids and flavonol glycosides in Tunisian Morus species by HPLC-DAD and HPLC–MS’, Journal of Functional Foods, 4, pp. 367–374

Tietel, Z., Weiss, B., Lewinsohn, E., Fallik, E., and Porat, R. (2010) ‘Improving taste and peel color of early-season Satsuma mandarins by combining high-temperature conditioning and degreening treatments’, Postharvest Biology and Technology, 57, pp. 1–5

Ting, S. V., Rouseff, R. L., Dougherty, M. H., and Attaway, J. A. (1979) ‘Determination of some methoxylated flavones in citrus juices by high performance liquid chromatography’, Journal of Food Science, 44, pp. 69–71

Treutter, D., 2005 ‘Significance of flavonoids in plant resistance and enhancement of their biosynthesis’, Plant Biology, 7, pp. 581–591

Uchida, K., Matsumoto, M., Kobayashi, A., and Yamanishi, T. (1983) ‘Composition of oxygenated compounds in peel oil from citrus iyo and its variation during Storage’, Agricultural and Biological Chemistry, 47, pp. 1841–1845

Zhang, J. Y., Zhang, Q., Zhang, H. X., Ma, Q., Lu, J. Q., and Qiao, Y. J. (2012) ‘Characterization of polymethoxylated flavonoids (PMFs) in the peels of ‘Shatangju’ Mandarin (Citrus reticulata Blanco) by online high-performance liquid chromatography coupled to photodiode array detection and electrospray tandem mass spectrometry’, Journal of Agricultural and Food Chemistry. 60, pp. 9023–9034

Zhao, Y. (2012) ‘Auxin biosynthesis: A simple two-step pathway converts tryptophan to indole-3-acetic acid in plants’, Molecular Plant 5, pp. 334–338

Zoratti, L., Karppinen, K., Escobar, A. L., Häggman, H., and Jaakola, L. (2014) ‘Light-controlled flavonoid biosynthesis in fruits’, Frontiers in Plant Science, 5, pp. 1-16

DOI: https://doi.org/10.21776/ub.afssaae.2023.006.02.6


  • There are currently no refbacks.

Copyright (c) 2023 Muharfiza Muharfiza, Dimas Firmanda Al-Riza, Nie Sen, Yasushi Kohno, Tetsuhito Suzuki, Makoto Kuramoto, Yuichi Ogawa, Naoshi Kondo

Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.