Abstract. Java apple (Syzygium samarangenese [Blume] Merrill & L.M. Perry. 'Thabthimchan') fruit bruise easily, and are highly susceptible to weight loss after.
Effect of Low Temperature on Physiological and Biochemical Changes in Java Apple ‘Thabthimchan’ W. Imsabai1, W. Somsuan2 and S. Ketsa3 Department of Horticulture, Faculty of Agriculture at Kamphaeng Saen, Kasetsart University, Nakhon Pathom, Thailand 2 Agriculture Office of Pathumthani Province, Department of Agriculture Extension, Pathumthani, Thailand 3 Department of Horticulture, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
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Keywords: chilling injury, pitting, vitamin C, ion leakage, antioxidant, lipoxygenase, superoxide dismutase, rose apple, Syzygium samarangenese Abstract Java apple (Syzygium samarangenese [Blume] Merrill & L.M. Perry ‘Thabthimchan’) fruit bruise easily, and are highly susceptible to weight loss after harvest. The objective of this research was to study the effect of low temperature on quality and biochemical changes of Java apple fruit. Java apple fruit were stored at 6 or 18C (90-92%RH) for 14 days. Fruit were evaluated for chilling injury index (pitting), weight loss, firmness, soluble solids content (SSC), titratable acidity (TA), peel color, ion leakage, vitamin C content, anthocyanin content, respiration rate, ethylene production, total antioxidant capacity (TAC), and lipoxygenase (LOX) and superoxide dismutase (SOD) activities every 2 days. The results indicated that in 6C stored Java apple fruit skin pitting (chilling injury: CI symptom) occurred and these fruit had higher ion leakage than those fruit stored at 18C. Fruit stored at 6C showed surface pitting on day 4 of storage, coinciding with an increase in ion leakage. Java apple fruit stored at 18C did not show any CI symptoms. Fruit firmness, SSC, TA, peel color and anthocyanin content did not change during fruit storage at 6 or 18C. Respiration rate, ethylene production, weight loss and vitamin C content and TAC of fruit stored at 6C were lower than those in fruit stored at 18C. LOX activity of fruit stored at 18C remained constant throughout the storage period. On the other hand, fruit stored at 6C showed high LOX activity on day 2 of storage, while SOD activity of fruit stored at 6 or 18C increased during storage. The results suggested that CI of Java apple fruit is closely correlated with ion leakage in fruit skin, vitamin C content and TAC. INTRODUCTION Java apple or rose apple (Syzygium samarangenese [Blume] Merrill & L.M. Perry ‘Thabthimchan’) fruit bruise easily, and are highly susceptible to weight loss after harvest. It is well known that storage of fruits and vegetables at low temperature is an effective method to maintain the fruit quality and extend shelf life (Isenberg, 1979), because low temperatures reduce the respiration and ethylene production of the commodities. However, Java apple, a tropical fruit, is sensitive to chilling injury when stored below a critical temperature (10-12C). Chilling injury (CI) symptoms of Java apple fruit are surface pitting and scald. The shelf life of Java apple is reduced by CI symptom when stored at low temperature. The ion leakage has been used as the indicator of cell membrane damage in CI fruit. The structural integrity of membranes might be compromised due to lipid peroxidation as a result of elevated ROS (reactive oxygen species). In maize, lower lipoxygenase (LOX) activity was related to chilling resistance (Pinhero et al., 1998). LOX might be responsible for catalyzed lipid peroxidation in response to chilling stress. ROS has been reported to associate with the CI fruit (Hodges et. al., 2004). ROS could cause the membrane damage, consequently, loss in membrane permeability. Fruit have to protected from the harmful effect of ROS by a complex antioxidant system, Proc. Vth International Conference Postharvest Unlimited Eds.: G.A. Manganaris et al. Acta Hort. 1079, ISHS 2015
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including 1) antioxidant compounds, such as, ascorbic acid (vitamin C) and glutathione, and 2) antioxidant enzymes, such as, superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) (Cao et al., 2011). CI in soursop (Annona muricata L.) fruit storage at 16C contributed to reduction of the synthesis of vitamin C content accompanied with CI increase (Moreno-Hernández et al., 2014). The hypothesis of the research is that Java apple fruit stored at 6C will develop CI symptoms accompanied by ion leakage and higher LOX activity, while SOD activity, vitamin C content and total antioxidant capacity (TAC) will decrease compared with fruits stored at 18C. Therefore, the objective of this research was the comparative investigation of the evolution of CI symptoms, fruit quality and the activities of lipoxygenase (LOX) and superoxide dismutase (SOD) of Java apple fruit during storage at 6C (chilling temperature) and 18C (non-chilling temperature). MATERIALS AND METHODS Java apple fruit were harvested at 45 days after full bloom and transported to laboratory within 2 h. The fruit were selected for uniformity of their color, size and shape. Java apple fruit were stored at 6 or 18C (90-92%RH) for 14 days. Fruit were evaluated every 2 days for chilling injury (pitting) index, weight loss, fruit firmness, soluble solids content (SSC), titratable acidity (TA) (AOAC, 1990), peel color, ion leakage (GonzálezAguilar et al., 2004), vitamin C content (by a modified method of Roe et al., 1948), anthocyanin content, respiration rate, ethylene production, total antioxidant capacity (TAC) by the Ferric Reducing Ability of Plasma (FRAP) Assay (Benzie and Strain, 1996). The fruit skin tissue was frozen with liquid nitrogen and extracts were analyzed for the activities of lipoxygenase (LOX) (Wang et al., 2004) and superoxide dismutase (SOD) (Chaiprasart, 2001). RESULTS AND DISCUSSION Java apple fruit stored at 6C developed surface pitting (chilling injury: CI symptom) (Fig. 1B,C) and these fruit had higher ion leakage than those fruit stored at 18C (Fig. 2B). Fruit stored at 6C showed surface pitting on day 4 (Fig. 1B) of storage and this coincided with an increase in ion leakage (Fig. 2B). Java apple fruit stored at 18C did not show any CI symptoms (Figs. 1D, 2A). The increase in ion leakage with storage time has been reported in cucumber and eggplant and it was associated with CI symptoms (Kuo and Parkin, 1989; Concellon et al., 2005). The results indicated that ion leakage of fruit skin may be involved in CI appearance. The percentage of ion leakage has been used for indirect measurement of membrane damage and it is an indicator of CI (Murata, 1989). CI symptoms (surface pitting), suggests that the CI of Java apple fruit is related to membrane damage (Lyons, 1973). The activity of LOX of fruit stored at 18°C remained constant throughout the storage period. On the other hand, fruit stored at 6°C showed high LOX activity on day 2 of storage time and the LOX activity declined thereafter (Fig. 3A) and Java apple fruit CI symptom occurred on day 4 (Fig. 2A). This indicated that low temperature (6°C) induced LOX activity increase resulting in lipid peroxidation. The product from lipid peroxidation is cis-trans diene which is the oxidative residue or ROS. The cis-trans diene might destroy the cell membrane, consequently, loss of permeability and association with increase in ion leakage. This result suggested that LOX may be involved in generating peroxidative damage in lipids membrane of Java apple fruit. As a report in cucumber stored at 2C, it was found that the activity of LOX increased on day 6-9 and decreased with storage time coincide with the highest of CI severity on day 6 (Mao et al., 2007). SOD is an antioxidant enzyme and it has been reported that its activity may be attributed to reduction in CI symptoms by the gradual cooling (from 15 to 0C) treatment before storage of kiwifruit at 0C (Yang et al., 2012). The result of SOD activity in Java fruit stored at 6 or 18C increased during storage period, and the SOD activity was the same level in fruit stored at both temperatures (Fig. 3B). Fruit firmness, fruit skin color, SS and TA of fruit stored at 6 and 18°C were not 244
significantly different (data not shown). Weight loss of fruit stored at all temperatures increased with storage time (Fig. 2C). Weight loss and vitamin C content of fruit stored at 6°C were lower than those fruit stored at 18°C (Fig. 2C,D). Vitamin C is one kind of antioxidant which reduces CI symptoms of some fruits storage at low temperature. The pattern of respiration rate did not have a peak of respiration because of Java apple fruit is a non-climacteric fruit (Akamine and Goo, 1979). The respiration rate and ethylene production of fruit stored at 6 and 18°C slightly increased with storage time, and both were higher in fruit held at 18°C than at 6°C (Fig. 3C,D). CONCLUSIONS The recommendation is to store Java apple fruit at 18C which will keep the fruit for 10 days without surface pitting and minimal weight loss. The CI symptom (surface pitting) of Java apple fruits is closely associated with higher ion leakage and lower vitamin C content and TAC in cold stored fruit. The result suggested that LOX activity may be attributed to increase in skin pitting of Java apple fruit stored at chilling temperature. ACKNOWLEDGEMENTS This work was financially supported by Kasetsart University Research and Development Institute (KURDI). Literature Cited Akamine, E.K. and Goo, T. 1979. Respiration and ethylene production of fruits of species and cultivars of Psidium and species of Eugenia. J. Amer. Soc. Hort. Sci. 104:632635. AOAC. 1990. Official Method of Analysis. Association of Official Analytical Chemists, Inc., Virginia. Benzie, I.F.F. and Strain, J.J. 1996. Ferric reducing ability of plasma (FRAP) as a measure of antioxidant power: The FRAP assay. Anal. Biochem. 239:70-76. Chaiprasart, P. 2001. Physiological and biochemical changes during occurrence of chilling injury in banana fruits and applicable techniques to reduce its damage. Ph.D. Thesis, University of Tsukuba. Cao, S.F., Zheng, Y.H., Wang, K.T., Jin, P. and Rui, H.J. 2009. Methyl jasmonate reduces chilling injury and enhances antioxidant enzyme activity in postharvest loquat fruit. Food Chem. 115:1458-1463. Concellon, A., Anon, M.C. and Chaves, A.R. 2005. Effect of chilling on ethylene production in eggplant fruit. Food Chem. 92:63-69. González-Aguilar, G.A., Tiznado-Hernández, M.E., Zavaleta-Gatica, R. and MartínezTéllez, M.A. 2004. Methyl jasmonate treatments reduce chilling injury and activate the defense response of guava fruits. Biochem. Biophys. Res. Commun. 313:694-701. Hodges, D.M., Lester, G.E., Munro, K.D. and Toivonen, P.M. 2004. Oxidative stress: importance for postharvest quality. HortScience 39:924-929. Isenberg, F.M.R. 1979. Controlled atmosphere storage of vegetable. Hort. Rev. 1:337389. Lyons, J.M. 1973. Chilling injury in plants. Ann. Rev. Plant Physiol. 24:445-466. Mao, L., Pang, H., Wang, G. and Zhu, C. 2007. Phospholipase D and lipoxygenase activity of cucumber fruit in response to chilling stress. Postharvest Biol. Technol. 44:42-47. Moreno-Hernández, C.L., Sáyago-Ayerdi, S.G., Garcia-Galindo, H.S., Mata-Montes De Oca, M. and Montalvo-González, E. 2014. Effect of the application of 1methylcyclopropene and wax emulsions on proximate analysis and some antioxidants of soursop (Annona muricata L.). Sci. World J. 1-7, article ID:896853. Murata, T. 1989. Relation of chilling stress to membrane permeability. p.201-209. In: C.Y. Wang (ed.), Chilling Injury of Horticultural Crops. Boca Raton, FL: CRC Press. Pinhero, R.G., Paliyath, G., Yada, R.Y. and Murr, D.P. 1998. Modulation of 245
phospholipase D and lipoxygenase activities during chilling relation to chilling tolerance of maize seedlings. Plant Physiol. Biochem. 36:213-224. Roe, J.H., Milles, M.B., Oesterling, M.J. and Damron, C.M. 1948. The determination of diketo-l-gulonic acid, dehydro-l-ascorbic acid and l-ascorbic acid in the same tissue extract by the 2,4 dinitrophenylhydrazine method. J. Biol. Chem. 174:201-208. Wang, Y.S., Tian, S.P., Xu, Y., Qin, G.Z. and Yao, H.J. 2004. Changes in the activities of pro- and anti-oxidant enzymes in peach fruit inoculated with Cryptococcus laurentii or Penicillium expansum at 0 or 20°C. Postharvest Biol. Technol. 34:21-28. Yang, Q., Rao, J., Yi, S., Meng, K., Wu, J. and Hou, Y. 2012. Antioxidant enzyme activity and chilling injury during low-temperature storage of kiwifruit cv. Hongyang exposed to gradual postharvest cooling. Hort. Env. Biotechnol. 53:505-512. Figures
Fig. 1. Java apple fruit before storage (A) and fruit stored at 6C for 4 (B) and 7 days (C), respectively, and fruit stored at 18C for 7 days (D). White arrow indicates the surface pitting.
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Fig. 2. CI index (A), ion leakage of skin (B), weight loss (C), vitamin C content (D) and total antioxidant capacity (E) of java apple fruit stored at 6C ( ) or 18C ( ) for 14 days. na (not analysed), ns (not significantly different), * (significantly different at p
