- Email: [email protected]
Endogenous ethylene regulates accumulation of α- and β-carotene in the pulp of harvested durian fruit
Postharvest Biology and Technology 110 (2015) 18–23
Contents lists available at ScienceDirect
Postharvest Biology and Technology journal homepage: www.elsevier.com/locate/postharvbio
Endogenous ethylene regulates accumulation of the pulp of harvested durian fruit
a- and b-carotene in
Apinya Wisutiamonkula , Saichol Ketsaa,b,* , Wouter G. van Doornc,1 a b c
Department of Horticulture, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand Academy of Science, The Royal Society of Thailand, Dusit, Bangkok 10300, Thailand Mann Laboratory, Department of Plant Sciences, University of California, Davis 95616, CA, USA
A R T I C L E I N F O
A B S T R A C T
Article history: Received 19 January 2015 Received in revised form 29 June 2015 Accepted 30 June 2015 Available online xxx
Durian (Durio zibethinus Murr.) cv. Chanee fruits were harvested at commercial maturity and stored at 25 C for 9 days. Respiration rates and ethylene production increased during storage, while pulp firmness decreased. The concentrations of the two main pulp carotenoids (a- carotene and b-carotene) increased by more than 30% during storage. The minor carotenoids zeaxanthin also increased, while an increase in lutein was not statistically different from controls. Treatment at 25 C with 500 mL L 1 1-methylcyclopropene (1-MCP) for 12 h delayed the increase in respiration rate and in ethylene production. It also resulted in a later decrease in pulp firmness. 1-MCP largely prevented the increase in pulp carotenoid concentrations. Ethephon treatment (brushing the stem cut surface) increased the measured ethylene and slightly hastened the decrease in pulp firmness, but did not measurably affect the respiration and carotenoid concentrations. It is concluded that the postharvest increase in pulp a-carotene and b-carotene concentrations is an integral part of pulp ripening in this cultivar. ã 2015 Elsevier B.V. All rights reserved.
Keywords:
b-Carotene a-Carotene Lutein Zeaxanthin Ripening
1. Introduction Durian is a tropical fruit with a typical smell and taste. Durian fruit is chilling-sensitive, and is therefore often stored at about 20– 25 C, i.e. only slightly below ambient temperatures in the tropics (with maxima about 30–33 C). Fruit ripening is regulated by endogenous ethylene, as 1-MCP (1-methylcyclopropene), an inhibitor of ethylene perception (Blankenship and Dole, 2003; Watkins, 2006) delayed softening (Maninang et al., 2011; Amornputti et al., 2014). Fruit pulp colour depends on the durian cultivar, varying between pale to deep yellow. Yellow fruit colour is often due to carotenoids (Wei et al., 2014). We previously reported that the pale yellow pulp in ripe (ready to eat) cv. Monthong and the deep yellow colour in ripe cv. Chanee were correlated with an 11-fold higher concentration of b-carotene and about a 60-fold higher concentration of a-carotene in ripe cv. Chanee. These two carotenoids accounted for about the total carotenoid concentration in the pulp, as the levels of lutein and zeaxanthin were very low (Wisutiamonkul et al., 2015).
* Corresponding author. Fax: +66 2 579 1951. E-mail address: [email protected] (S. Ketsa). Deceased.
1
http://dx.doi.org/10.1016/j.postharvbio.2015.06.017 0925-5214/ ã 2015 Elsevier B.V. All rights reserved.
Carotenoid synthesis in fruit was inhibited by 1-MCP, depending on the carotenoid and whether pulp ripening in the species is regulated by endogenous ethylene (climacteric fruit) or not (nonclimacteric fruit). In non-climacteric fruit no effect is to be expected, but in climacteric fruit the results were not uniform. For example, in mature green apricot (Prunus armeniaca) fruit, which is climacteric, 1-MCP had no effect on the increase of the concentrations of phytoene, phytofluene and b-carotene (Marty et al., 2005) while 1-MCP prevented the increase in lycopene and b-carotene concentrations in the climacteric papaya fruit (Carica papaya; Fabi et al., 2007) and total carotenoids in the climacteric tomato (Moretti et al., 2002) and dragon fruit (Selenicereus megalanthus; Deaquiz et al., 2014). 1-MCP applied before ripening also inhibited the increased expression of genes involved in carotenoid synthesis, for example in nectarine (Ziliotto et al., 2008). Ethylene or ethephon (2-chloroethylphosphonic acid), a compound that slowly releases ethylene, has been used to hasten fruit ripening, e.g. in banana (Jiang et al., 1999). Durian can also ripen with ethylene (Ketsa and Pongkool, 1995) or ethephon (Cheyglinted, 1993). Ethylene induced peel yellowing or even browning. Consumers do not prefer this as it seems that the fruit is not fresh. For this reason many growers, wholesalers, and retailers in Thailand induce durian ripening by quickly dipping the fruit stalk (peduncle) into an ethephon solution, or brush the stalk with
A. Wisutiamonkul et al. / Postharvest Biology and Technology 110 (2015) 18–23
such a solution. Concentrations used vary mostly between about 3000–5000 mL L 1 or higher. This treatment prevents peel yellowing or browning (Paull and Ketsa, 2014). Cheyglinted (1993) showed the rationale of this ethephon treatment. Cv. Chanee fruit harvested at 75% maturity either failed to ripen or ripened abnormally, whilst fruit harvested at 85% maturity reached good eating quality. Normal ripening, i.e. yellowing of the pulp and development of full flavour and aroma of fruit harvested at 75% maturity was obtained if treated with 1000 or 2000 mL L 1 ethephon at the fruit stalk. Ripening of 85% mature fruit was slightly advanced when treated with ethephon. Harvesting at 75% maturity combined with ethephon treatment extended shelf life, compared with later harvesting and no such treatment. It is not known if durian pulp carotenoid production after harvest is regulated by endogenous ethylene. The objective of this study, therefore, was to investigate the effect of 1-MCP. Additionally we tested the effect of ethephon, brushed at the fruit stalk. We used cv. Chanee fruit. It was hypothesized that carotenoid synthesis would be part of the ripening process, hence be inhibited by 1-MCP and promoted by ethephon. 2. Materials and methods
19
equatorial region of each fruit. Values were averaged per fruit, then over the batch tested. Pulp firmness was measured using a handheld fruit firmness tester (Effegi, Alfonsine, Italy) equipped with a cylindrical plunger 0.5 cm in diameter. The plunger was inserted to a depth of 0.5 cm and recorded in Newtons per square cm. Pulp TSS was determined using 4 g FW, adding 12 mL of distilled water, followed by homogenization. The homogenate was centrifuged at 12,000 g for 25 min at 4 C. The TSS was measured in the supernatant, using a hand-held refractometer (Atago, Tokyo, Japan) and multiplied by 3 to account for the dilution. Total carotenoid concentrations, and concentrations of individual carotenoids, were determined as described in Wisutiamonkul et al. (2015). 2.5. Statistical analysis Six replicates per treatment and 18 fruit per treatment were used in all experiments. Data were analyzed using ANOVA and least significant difference (LSD) at P 0.05 for firmness, TSS, colour, respiration, ethylene production, and total and individual carotenoids. Data of carotenoids were also compared using Duncan’s new multiple range test (DMRT), at P 0.05.
2.1. Plant material
One group (100 fruit) served as controls. In another group (100 fruit) an aqueous 4800 mL L 1ethephon was brushed at the surface of the cut stalk, applying about 0.2 mL per stalk and dried in air at 25 C. A third group was placed in a 71 L sealed container and treated with 500 mL L 1 1-MCP for 12 h at 25 C. 1-MCP was generated by adding water to 1-MCP (EthylBloc1, Floralife Inc., Walterboro, SC, USA) powder, which was placed a glass vial. This resulted in a final concentration of 500 mL L 1 of 1-MCP in the air. Fans were used in the chambers to maintain air circulation. A fourth group of fruit was first treated with 1-MCP, as described above, and then immediately brushed with ethephon and dried as described. Fruit were stored at 25 C and 85-90% RH. 2.3. Ethylene production and respiration rate Measurement of ethylene production and respiration rate followed the method described by Palapol et al. (2015). Individual durian fruits were placed into 13.5 L airtight jars for 30 min at 25 C, after which a 5 mL gas sample was taken from the air space and injected into a gas chromatographs equipped with a flame ionization detector (GC-14, Shimadzu, Tokyo, Japan) for ethylene, and a thermal conductivity detector (GC-RIA, Shimadzu, Kyoto, Japan) for carbon dioxide. 2.4. Colour, total soluble solids (TSS), firmness, and carotenoids Pulp colour was quantified using a Minolta Chromameter (Model CR-300, Minolta, Osaka, Japan), recording hue, L* and b* (Hunter scale) values. Colour readings were taken twice at the
A 300 Pulp firmness (N cm -2)
2.2. Ethephon and 1-MCP treatments
350 LSD0.05 = 42.20
250 200 150 100 50 0
B
30 Total soluble solids (%)
Flowers on durian (Durio zibethinus Murr. cv. Chanee) trees, growing in a commercial orchard in Chanthaburi province (Eastern Thailand), were tagged one week after anthesis. Fruit were harvested 15 weeks (about 105 days) after anthesis, which is the commercially mature harvest stage. Fruit were submerged in 0.5 mL L 1 imazalil solution for 20 s to control fruit rot caused by Phytophthora palmivora. Fruit were transported to the laboratory in a temperature-controlled truck (25 C), where they arrived within a day of harvest. Transport took about 6 h.
LSD0.05 = 2.77
25
20 15
10 5
0 0
1
2
3
4
5
6
7
8
9
Days after treatment Fig. 1. Pulp firmness (A) and total soluble solids (B) in the pulp of durian (Durio zibethinus Murr.) cv. Chanee fruit during ripening at 25 C. Treatments are controls ( ), ethephon (D), 1-MCP (*) and 1-MCP + ethephon (~). Data are means of six replications, each containing 3 fruit. LSD is indicated by a bar.
20
3. Results 3.1. Firmness, TSS and colour During ripening at 25 C, pulp firmness of the controls decreased rapidly from day 2 (Fig. 1). The same was found in ethephon-treated fruit. Treatment with 1-MCP prevented the decrease in firmness for 6-7 days of ripening at 25 C (Fig. 1A). However, between day 7 and 9 a decrease in firmness was found in this fruit which was similar to the rate found in the controls during day 2–5 (Fig. 1A). In fruit treated with 1-MCP and ethephon, pulp firmness was not affected for 3–4 days, then decreased rapidly from day 5 onward (Fig. 1A). Controls showed an increase in TSS, which was delayed by 1-MCP treatment, while ethephon had no effect (Fig. 1B). At harvest the pulp colour was light cream. After 4 days of storage at 25 C the pulp was dark yellow. In controls the L* value (Fig. 2A) and hue value (Fig. 2C) of the pulp decreased while the b* value (Fig. 2B) increased. These effects were delayed by the 1-MCP treatment and were not affected by the ethephon treatment. 3.2. Respiration and ethylene production rates The respiration rate (carbon dioxide production) of the whole control fruit increased from day 0 to 5 of storage at 25 C (Fig. 3A). Ethephon had no effect on respiration (Fig. 3A). 1-MCP delayed the increase in respiration rate by about 6 days (Fig. 3A). The ethylene production rate of the controls increased throughout the 9 days of storage at 25 C (Fig. 3B). Until day 6
Ethylene production (μl C2H4 kg-1 h-1) Carbon dioxide production (mg CO 2 kg-1 h-1)
A. Wisutiamonkul et al. / Postharvest Biology and Technology 110 (2015) 18–23
400
A
350
LSD0.05 = 28.0
300
250 200 150 100 50 0
B 30
LSD0.05 = 2.85
25 20
15 10
5 0
0
100
A
L* value
95
85 80
70
B 50
b* value
3
4
5
6
7
8
9
Fig. 3. Respiration (A) and ethylene production (B) of durian (Durio zibethinus Murr.) cv. Chanee fruit during ripening at 25 C. Treatment are controls ( ), ethephon (D), 1-MCP (*) and 1-MCP + ethephon (~). Data are means of six replications, each containing 3 fruit. LSD is indicated by a bar.
75
LSD0.05 = 1.74
45
this increase was inhibited by 1-MCP. The ethephon treatment increased the amount of measured ethylene, with a large effect during day 1–3. In fruit treated with 1-MCP and ethephon, ethylene production was still higher than the control fruit but was less than the ethephon-treated fruit (Fig. 3B). 3.3. Carotenoids
40
As described by Wisutiamonkul et al. (2015), the pulp
a-carotene concentration at mature harvesting accounted for about 20% of total carotenoids, and b-carotene for about 80%
35 30
C LSD0.05 = 0.50
95
Hue value
2
Days after treatment
LSD0.05 = 1.33
90
1
90
85 80 0
1
2
3 4 5 6 Days after treatment
7
8
9
Fig. 2. L* (A), b* (B) and hue angle (C) values in the pulp of durian (Durio zibethinus Murr.) cv. Chanee fruit during ripening at 25 C. Treatments are controls ( ), ethephon (D), 1-MCP (*) and 1-MCP + ethephon (~). Data are means of six replications, each containing 3 fruit. LSD is indicated by a bar.
(Fig. 4). The xanthophylls lutein and zeaxanthin were present in small concentrations (Fig. 4). A fifth carotenoid could not be identified. The data showed very low levels of this compound in the controls, with a HPLC peak just before the peak of a-carotene (data not shown). During storage until the stage where the fruit was ready to eat, total carotenoids in the pulp of control fruit increased by a factor of about 2.5 (Fig. 4A). This increase was very largely due to increased concentrations of pulp a-carotene and b-carotene (Fig. 4B, C). The a-carotene concentration increased by 32% and the b-carotene concentration by 36%. Concentrations of zeaxanthin also increased during storage (Fig. 4E), while those of lutein were not statistically different from controls (Fig. 4D). Treatment with ethephon did not affect the total carotenoid concentrations (Fig. 4A). 1-MCP treatment prevented the increase in a- and b-carotene concentrations (Fig. 4B, C), although a late (day 4–9) increase was observed in the b-carotene concentration
A. Wisutiamonkul et al. / Postharvest Biology and Technology 110 (2015) 18–23
40
a a
b b
20
b b
0.20
A
a a
a ab b b
30
b b
D
10 LSD0.05 = 0.58
7
a a
a a
a a
a a
6
5
b b
b b
b b
b b
C 35
LSD0.05 = 3.48
30
a a
a a
a a
b b
b b
b b
15
0
1
2
3
4
5
6
LSD0.05 = 0.036
0.16
0.14 0.12
E
2.0
LSD0.05 = 0.8
1.5
1.0 0.5 0.0 0
1
2
7
8
a a
a a
a a
b b
b b
b b
3
4
5
a a
a ab b b
b c 6
7
8
9
Days after treatment
a ab b b
25 20
0.18
0.10
B
8
4
β-Carotene (μg g-1 FW)
a a
Lutein (μg g-1 FW)
LSD0.05 = 4.42
Zeaxanthin (ng g-1 FW)
α-Carotene (μg g-1 FW)
Total carotenoids (μg g-1 FW)
50
21
9
Days after treatment Fig. 4. Total carotenoid concentrations (A), and the concentrations of a-carotene (B), b-carotene (C), lutein (D), and zeaxanthin (E) in the pulp of durian (Durio zibethinus Murr.) cv. Chanee fruit during ripening at 25 C. Treatment are controls ( ), ethephon (D), 1-MCP (*) and 1-MCP + ethephon (~). Data are means of six replications, each containing 3 fruit. LSD is indicated by a bar. Data in (A)–(E) were compared on various harvest dates, with a different combination of letters showing statistical difference at P 0.05 by DMRT; data in (D) showed no differences.
of 1-MCP-treated fruit (Fig. 4C). 1-MCP also delayed the increase in zeaxanthin concentrations (Fig. 4E). Although 1-MCP seemed to largely prevent the increase in lutein concentrations, no statistically significant differences were found between single harvest times (Fig. 4D). It should be noted that after the 1-MCP treatment total carotenoid concentrations showed an increase between day 0 and 3–4 (Fig. 4A). This increase was not accounted for by the sum of the four individual carotenoids determined (compare Fig. 4A with B–E). Similarly in fruit treated with 1-MCP and ethephon, treatment did not affect significantly total carotenoids, and both minor and major carotenoids (Fig. 4). Correlation coefficients of a-carotene concentrations with objective colour values L*, hue and b* were 0.80, 0.74, and 0.73, respectively, and of the b-carotene concentration 0.87, 0.81, and 0.84, respectively (Table 1). With the exception of the lutein concentrations, all parameters measured in the present study showed high correlation coefficients (Table 1).
4. Discussion 1-MCP prevented, at least initially, the increase in a- and b-carotene concentrations, as well as in zeaxanthin concentrations, showing that these were regulated by endogenous ethylene. Similarly, 1-MCP inhibited the increase in the rates of respiration and ethylene production, and the decrease in pulp firmness. The data therefore indicate that the carotenoid accumulation at a late stage of ripening is an integral part of the ethylene-regulated ripening processes. These data are confirmed by the finding that the increase in fruit ethylene production preceded a- and b-carotene accumulation. The change in pulp colour was correlated in time with the increase in a-carotene and b-carotene concentrations. Additionally, 1-MCP inhibited pulp yellowing. The data therefore suggest that a-carotene and b-carotene were the cause of the increase in yellowness during ripening. Positive b* values, and lower hue
Table 1 Pearson’s correlation (r) comparing relatively between physiological and chemical measurements in durian (Durio zibethinus Murr.) cv. Chanee pulp during ripening at 25 C. Pearson’s correlation Total carotenoids a-Carotene b-Carotene Lutein Zeaxanthin L* value b* Value Hue value No star = non-significant. * P 0.05. *** P 0.001.
Total carotenoids – 0.74*** 0.72*** 0.24 0.80*** 0.80*** 0.77*** 0.87***
a-Carotene
b-Carotene
Lutein
Zeaxanthin
L* value
b* Value
Hue value
– 0.84*** 0.44* 0.77*** 0.80*** 0.73*** 0.74***
– 0.34 0.87*** 0.87*** 0.84*** 0.81***
– 0.39* 0.05 0.03 0.00
– 0.80*** 0.76*** 0.75***
– 0.96*** 0.95***
– 0.95***
–
22
A. Wisutiamonkul et al. / Postharvest Biology and Technology 110 (2015) 18–23
angles describe the intensity of the yellow colour, while the L* values describe lightness (Selahle et al., 2015). We found high correlation coefficients between a- and b-carotene concentrations with L*, hue and b*. Similarly, in mango fruit flesh the b-carotene concentration was positively correlated with yellowness, and was also correlated with the Hunter a* and L* values (Ornelas-Paz et al., 2008) and in sweet peper b-carotene concentrations showed a correlation with the hue and b* values (Selahle et al., 2015). In other fruit an increase in b-carotene concentrations in flesh/pulp during the postharvest phase has been reported. For example, in mango that ripened for 8 days at 18–19 C a small increase in fruit flesh b-carotene concentration was found (Vásquez-Caicedo et al., 2006) whilst in mango fruit stored for 16 days at 28 C the concentration of b-carotene in the fruit flesh considerably increased (Ornelas-Paz et al., 2008). In mandarin (Citrus unshiu) fruit stored at 5 , 20 , or 30 C for 21 days, the b-carotene concentration in fruit flesh (juice sacs) increased at 20 and 30 C, while no effect was found at 5 C (Matsumoto et al., 2009). Increased concentration were also reported in winter squash (Cucurbita maxima), stored at 20 C (Arvayo-Ortiz et al., 1994) and in sweet pepper stored for 21 days at 7.5 C and for 3 days at 20 C (Selahle et al., 2015). By contrast, tomato fruit stored for 21 days in the dark at 12–14 C showed no change in fruit flesh b-carotene concentration (Liu et al., 2009). Storage of kumquat (Fortunella japonica) fruit for 21 days at 17 C also had no effect on the levels of b-carotene (Schirra et al., 2008). Apart from our previous paper (Wisutiamonkul et al., 2015) and the more detailed data shown now, no reports apparently have been published on changes in a-carotene concentrations in fruit flesh after harvest. In other fruit the zeaxanthin concentration reportedly increased or remained stable. For example in mandarin (C. unshiu) stored at 5 , 20 , or 30 C for 21 days, zeaxanthin concentrations increased early at 30 C, and later at 20 C. No change was found at 5 C (Matsumoto et al., 2009). Storage of kumquat (Fortunella japonica) fruit for 21 days at 17 C had no effect on zeaxanthin (Schirra et al., 2008). Very little seems reported on lutein concentrations. During the experiment of Schirra et al. (2008) on kumquat storage the lutein concentration decreased. Ethephon has been widely used as a replacement for ethylene treatment in agriculture (Abeles et al., 1992). Treatment with ethephon, thus with exogenous ethylene, did not affect the parameters studied with the exception of an increase in the amount of measured ethylene, and a very small hastening effect on firmness decrease. The increase in the measured ethylene detected in ethephon-treated fruit may not be due to an increase in endogenous ethylene production, but it could be due to the release of ethylene from ethephon (Yang, 1969), thus making the difference between the control (not treated) and the treated fruit. As shown in the Introduction, the ethephon treatment is used in practice to ensure full and rapid ripening of fruit that is harvested too early, whereby this can be a matter of only a few days. Ketsa and Daengkanit (1999) showed large differences in ethylene production, and cell wall hydrolase activities in fruit harvested at 102 and 109 days after anthesis, showing that a week difference in harvest has a large impact on the rate of ripening. The very small effect of ethephon on the parameters studied with the exception of an increase in the amount of measured ethylene in the present experiments means that the fruit was harvested at a relatively advanced stage, showing a full complement of endogenous ethylene production, and stimulated ripening processes. Our results show that endogenous ethylene regulates the accumulation of a- and b-carotene in durian pulp. The same (although only for b-carotene) apparently has only been reported previously in papaya fruit (Fabi et al., 2007). Regulation of a-carotene accumulation by endogenous ethylene seemingly has not been reported before.
It is concluded that a- and b-carotene accumulation during postharvest ripening is regulated by endogenous ethylene. The highest a- and b carotene concentrations are found in fruit that was ready for consumption (by day 5-9 of storage in the present experiments). Furthermore, the early small increase in zeaxanthin concentrations was regulated by endogenous ethylene. The data suggested that the increase in carotenoid concentrations is an ethylene-regulated ripening process in pulp of durian fruit. Acknowledgements The research was financially supported by the Royal Golden Jubilee PhD Program (PHD/0021/2553) of the Thailand Research Fund (TRF), Kasetsart University and the Higher Education Commission, Ministry of Education, Thailand. References Abeles, F.B., Morgan, P.W., Saltveit, M.E., 1992. Ethylene in Plant Biology. Academic Press Inc., San Diego. Amornputti, S., Ketsa, S., van Doorn, W.G., 2014. Effect of 1-methylcyclopropene (1MCP) on storage life of durian fruit. Postharvest Biol. Technol. 97, 111–114. Arvayo-Ortiz, R.M., Garza-Ortega, S., Yahia, E.M., 1994. Postharvest response of winter squash to hot-water treatment, temperature, and length of storage. HortTechnology 4, 253–255. Blankenship, S., Dole, J.M., 2003. 1-Methylcyclopropene: a review. Postharvest Biol. Technol. 28, 1–25. Cheyglinted, S., 1993. Effect of ethephon on the physio-chemical changes during the ripening of ‘Chanee’ durian (Durio zibethinus Murray) harvested at different maturity stages. MS Thesis. Los Banos College, The Philippines. Deaquiz, Y.A., Álvarez-Herrera, J., Fischer, G., 2014. Ethylene and 1-MCP affect the postharvest behavior of yellow pitahaya fruits (Selenicereus megalanthus Haw.). Agron. Colomb. 32, 44–51. Fabi, J.P., Cordenunsi, B.R., de Mattos Barreto, G.P., Mercadante, A.Z., Lajolo, F.M., Oliveira do Nascimento, J.R., 2007. Papaya fruit ripening: response to ethylene and 1-methylcyclopropene (1-MCP). J. Agric. Food Chem. 55, 6118–6123. Jiang, Y., Joyce, D.C., Macnish, A.J., 1999. Extension of the shelf life of banana fruit by 1-methylcyclopropene in combination with polyethylene bags. Postharvest Biol. Technol. 16, 187–193. Ketsa, S., Daengkanit, T., 1999. Firmness and activities of polygalacturonase, pectinesterase, b-galactosidase and cellulase in ripening durian harvested at different stages of maturity. Sci. Hortic. 80, 181–188. Ketsa, S., Pongkool, S., 1995. Effect of maturity stages and ethylene treatment on ripening of durian fruits. In: Frisinia, C., Mason, K., Faragher, J. (Eds.), Proceedings of Australasian Postharvest Horticulture Conference. Science and Technology for Fresh Food Revolution, Melbourne, Australia, pp. 67–72. Liu, L.H., Zabaras, D., Bennett, L.E., Aguas, P., Woonton, B.W., 2009. Effects of UV-C, red light and sun light on the carotenoid content and physical qualities of tomatoes during post-harvest storage. Food Chem. 115, 495–500. Maninang, J.S., Wongs-Aree, C., Kanlayanarat, S., Sugaya, S., Gemma, H., 2011. Influence of maturity and postharvest treatment on the volatile profile and physiological properties of the durian (Durio zibethinus Murray) fruit. Int. Food Res. J. 18, 1067–1075. Marty, I., Bureau, S., Sarkissian, G., Gouble, B., Audergon, J.M., Albagnac, G., 2005. Ethylene regulation of carotenoid accumulation and carotenogenic gene expression in colour-contrasted apricot varieties (Prunus armeniaca). J. Exp. Bot. 56, 1877–1886. Matsumoto, H., Ikoma, Y., Kato, M., Nakajima, N., Hasegawa, Y., 2009. Effect of postharvest temperature and ethylene on carotenoid accumulation in the flavedo and juice sacs of Satsuma mandarin (Citrus unshiu Marc.) fruit. J. Agric. Food Chem. 57, 4724–4732. Moretti, C.L., Araujo, A.L., Marouelli, W.A., Silva, W.L.C., 2002. 1-Methylcyclopropene delays tomato fruit ripening. Hortic. Brasil 20, 659–663. Ornelas-Paz, J.D.J., Yahia, E.M., Gardea, A.A., 2008. Changes in external and internal color during postharvest ripening of ‘Manila’ and ‘Ataulfo’ mango fruit and relationship with carotenoid content determined by liquid chromatography– APcl*-time-of-flight mass spectrometry. Postharvest Biol. Technol. 50, 145–152. Palapol, Y., Kunyamee, S., Thongkhum, M., Ketsa, S., Ferguson, I.B., van Doorn, W.G., 2015. Expression of expansin genes in the pulp and the dehiscence zone of ripening durian (Durio zibethinus) fruit. J. Plant Physiol. 182, 33–39. Paull, R.E., Ketsa, S., 2014. Durian: postharvest quality-maintenance guidelines. Cooperative Extension. University of Hawaii at Manoa. http://www.ctahr. hawaii.edu/oc/freepubs/pdf/F_N-27.pdf. Schirra, M., Palma, A., D'Aquino, S., Angioni, A., Minello, E.V., Melis, M., Cabras, P., 2008. Influence of postharvest hot water treatment on nutritional and functional properties of kumquat (Fortunella japonica Lour. Swingle, cv. Ovale) fruit. J. Agric. Food Chem. 56, 455–460. Selahle, K.M., Sivakumar, D., Jifon, J., Soundy, P., 2015. Postharvest responses of red and yellow sweet peppers grown under photo-selective nets. Food Chem. 173, 951–956.
A. Wisutiamonkul et al. / Postharvest Biology and Technology 110 (2015) 18–23 Vásquez-Caicedo, A.L., Heller, A., Neidhart, S., Carle, R., et al., 2006. Chromoplast morphology and b-carotene accumulation during postharvest ripening of mango cv. ‘Tommy Atkins’. J. Agric. Food Chem. 54, 5769–5776. Watkins, C.B., 2006. The use of 1-methylcyclopropene (1-MCP) on fruits and vegetables. Biotechnol. Adv. 24, 389–409. Wei, X., Chen, C., Yu, Q., Gady, A., Yu, Y., Liang, G., Gmitter, F.G., 2014. Comparison of carotenoid accumulation and biosynthetic gene expression between Valencia and Rohde Red Valencia sweet oranges. Plant Sci. 227, 28–36.
23
Wisutiamonkul, A., Promdang, S., Ketsa, S., van Doorn, W.G., 2015. Carotenoids in durian fruit pulp during growth and postharvest ripening. Food Chem. 180, 301– 305. Yang, S.F., 1969. Ethylene evolution from 2-chloroethylphosphonic acid. Plant Physiol. 44, 1203–1204. Ziliotto, F., Begheldo, M., Rasori, A., Bonghi, C., Tonutti, P., 2008. Transcriptome profiling of ripening nectarine (Prunus persica L. Batsch) fruit treated with 1MCP. J. Exp. Bot. 59, 2781–2791.
Contents lists available at ScienceDirect
Postharvest Biology and Technology journal homepage: www.elsevier.com/locate/postharvbio
Endogenous ethylene regulates accumulation of the pulp of harvested durian fruit
a- and b-carotene in
Apinya Wisutiamonkula , Saichol Ketsaa,b,* , Wouter G. van Doornc,1 a b c
Department of Horticulture, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand Academy of Science, The Royal Society of Thailand, Dusit, Bangkok 10300, Thailand Mann Laboratory, Department of Plant Sciences, University of California, Davis 95616, CA, USA
A R T I C L E I N F O
A B S T R A C T
Article history: Received 19 January 2015 Received in revised form 29 June 2015 Accepted 30 June 2015 Available online xxx
Durian (Durio zibethinus Murr.) cv. Chanee fruits were harvested at commercial maturity and stored at 25 C for 9 days. Respiration rates and ethylene production increased during storage, while pulp firmness decreased. The concentrations of the two main pulp carotenoids (a- carotene and b-carotene) increased by more than 30% during storage. The minor carotenoids zeaxanthin also increased, while an increase in lutein was not statistically different from controls. Treatment at 25 C with 500 mL L 1 1-methylcyclopropene (1-MCP) for 12 h delayed the increase in respiration rate and in ethylene production. It also resulted in a later decrease in pulp firmness. 1-MCP largely prevented the increase in pulp carotenoid concentrations. Ethephon treatment (brushing the stem cut surface) increased the measured ethylene and slightly hastened the decrease in pulp firmness, but did not measurably affect the respiration and carotenoid concentrations. It is concluded that the postharvest increase in pulp a-carotene and b-carotene concentrations is an integral part of pulp ripening in this cultivar. ã 2015 Elsevier B.V. All rights reserved.
Keywords:
b-Carotene a-Carotene Lutein Zeaxanthin Ripening
1. Introduction Durian is a tropical fruit with a typical smell and taste. Durian fruit is chilling-sensitive, and is therefore often stored at about 20– 25 C, i.e. only slightly below ambient temperatures in the tropics (with maxima about 30–33 C). Fruit ripening is regulated by endogenous ethylene, as 1-MCP (1-methylcyclopropene), an inhibitor of ethylene perception (Blankenship and Dole, 2003; Watkins, 2006) delayed softening (Maninang et al., 2011; Amornputti et al., 2014). Fruit pulp colour depends on the durian cultivar, varying between pale to deep yellow. Yellow fruit colour is often due to carotenoids (Wei et al., 2014). We previously reported that the pale yellow pulp in ripe (ready to eat) cv. Monthong and the deep yellow colour in ripe cv. Chanee were correlated with an 11-fold higher concentration of b-carotene and about a 60-fold higher concentration of a-carotene in ripe cv. Chanee. These two carotenoids accounted for about the total carotenoid concentration in the pulp, as the levels of lutein and zeaxanthin were very low (Wisutiamonkul et al., 2015).
* Corresponding author. Fax: +66 2 579 1951. E-mail address: [email protected] (S. Ketsa). Deceased.
1
http://dx.doi.org/10.1016/j.postharvbio.2015.06.017 0925-5214/ ã 2015 Elsevier B.V. All rights reserved.
Carotenoid synthesis in fruit was inhibited by 1-MCP, depending on the carotenoid and whether pulp ripening in the species is regulated by endogenous ethylene (climacteric fruit) or not (nonclimacteric fruit). In non-climacteric fruit no effect is to be expected, but in climacteric fruit the results were not uniform. For example, in mature green apricot (Prunus armeniaca) fruit, which is climacteric, 1-MCP had no effect on the increase of the concentrations of phytoene, phytofluene and b-carotene (Marty et al., 2005) while 1-MCP prevented the increase in lycopene and b-carotene concentrations in the climacteric papaya fruit (Carica papaya; Fabi et al., 2007) and total carotenoids in the climacteric tomato (Moretti et al., 2002) and dragon fruit (Selenicereus megalanthus; Deaquiz et al., 2014). 1-MCP applied before ripening also inhibited the increased expression of genes involved in carotenoid synthesis, for example in nectarine (Ziliotto et al., 2008). Ethylene or ethephon (2-chloroethylphosphonic acid), a compound that slowly releases ethylene, has been used to hasten fruit ripening, e.g. in banana (Jiang et al., 1999). Durian can also ripen with ethylene (Ketsa and Pongkool, 1995) or ethephon (Cheyglinted, 1993). Ethylene induced peel yellowing or even browning. Consumers do not prefer this as it seems that the fruit is not fresh. For this reason many growers, wholesalers, and retailers in Thailand induce durian ripening by quickly dipping the fruit stalk (peduncle) into an ethephon solution, or brush the stalk with
A. Wisutiamonkul et al. / Postharvest Biology and Technology 110 (2015) 18–23
such a solution. Concentrations used vary mostly between about 3000–5000 mL L 1 or higher. This treatment prevents peel yellowing or browning (Paull and Ketsa, 2014). Cheyglinted (1993) showed the rationale of this ethephon treatment. Cv. Chanee fruit harvested at 75% maturity either failed to ripen or ripened abnormally, whilst fruit harvested at 85% maturity reached good eating quality. Normal ripening, i.e. yellowing of the pulp and development of full flavour and aroma of fruit harvested at 75% maturity was obtained if treated with 1000 or 2000 mL L 1 ethephon at the fruit stalk. Ripening of 85% mature fruit was slightly advanced when treated with ethephon. Harvesting at 75% maturity combined with ethephon treatment extended shelf life, compared with later harvesting and no such treatment. It is not known if durian pulp carotenoid production after harvest is regulated by endogenous ethylene. The objective of this study, therefore, was to investigate the effect of 1-MCP. Additionally we tested the effect of ethephon, brushed at the fruit stalk. We used cv. Chanee fruit. It was hypothesized that carotenoid synthesis would be part of the ripening process, hence be inhibited by 1-MCP and promoted by ethephon. 2. Materials and methods
19
equatorial region of each fruit. Values were averaged per fruit, then over the batch tested. Pulp firmness was measured using a handheld fruit firmness tester (Effegi, Alfonsine, Italy) equipped with a cylindrical plunger 0.5 cm in diameter. The plunger was inserted to a depth of 0.5 cm and recorded in Newtons per square cm. Pulp TSS was determined using 4 g FW, adding 12 mL of distilled water, followed by homogenization. The homogenate was centrifuged at 12,000 g for 25 min at 4 C. The TSS was measured in the supernatant, using a hand-held refractometer (Atago, Tokyo, Japan) and multiplied by 3 to account for the dilution. Total carotenoid concentrations, and concentrations of individual carotenoids, were determined as described in Wisutiamonkul et al. (2015). 2.5. Statistical analysis Six replicates per treatment and 18 fruit per treatment were used in all experiments. Data were analyzed using ANOVA and least significant difference (LSD) at P 0.05 for firmness, TSS, colour, respiration, ethylene production, and total and individual carotenoids. Data of carotenoids were also compared using Duncan’s new multiple range test (DMRT), at P 0.05.
2.1. Plant material
One group (100 fruit) served as controls. In another group (100 fruit) an aqueous 4800 mL L 1ethephon was brushed at the surface of the cut stalk, applying about 0.2 mL per stalk and dried in air at 25 C. A third group was placed in a 71 L sealed container and treated with 500 mL L 1 1-MCP for 12 h at 25 C. 1-MCP was generated by adding water to 1-MCP (EthylBloc1, Floralife Inc., Walterboro, SC, USA) powder, which was placed a glass vial. This resulted in a final concentration of 500 mL L 1 of 1-MCP in the air. Fans were used in the chambers to maintain air circulation. A fourth group of fruit was first treated with 1-MCP, as described above, and then immediately brushed with ethephon and dried as described. Fruit were stored at 25 C and 85-90% RH. 2.3. Ethylene production and respiration rate Measurement of ethylene production and respiration rate followed the method described by Palapol et al. (2015). Individual durian fruits were placed into 13.5 L airtight jars for 30 min at 25 C, after which a 5 mL gas sample was taken from the air space and injected into a gas chromatographs equipped with a flame ionization detector (GC-14, Shimadzu, Tokyo, Japan) for ethylene, and a thermal conductivity detector (GC-RIA, Shimadzu, Kyoto, Japan) for carbon dioxide. 2.4. Colour, total soluble solids (TSS), firmness, and carotenoids Pulp colour was quantified using a Minolta Chromameter (Model CR-300, Minolta, Osaka, Japan), recording hue, L* and b* (Hunter scale) values. Colour readings were taken twice at the
A 300 Pulp firmness (N cm -2)
2.2. Ethephon and 1-MCP treatments
350 LSD0.05 = 42.20
250 200 150 100 50 0
B
30 Total soluble solids (%)
Flowers on durian (Durio zibethinus Murr. cv. Chanee) trees, growing in a commercial orchard in Chanthaburi province (Eastern Thailand), were tagged one week after anthesis. Fruit were harvested 15 weeks (about 105 days) after anthesis, which is the commercially mature harvest stage. Fruit were submerged in 0.5 mL L 1 imazalil solution for 20 s to control fruit rot caused by Phytophthora palmivora. Fruit were transported to the laboratory in a temperature-controlled truck (25 C), where they arrived within a day of harvest. Transport took about 6 h.
LSD0.05 = 2.77
25
20 15
10 5
0 0
1
2
3
4
5
6
7
8
9
Days after treatment Fig. 1. Pulp firmness (A) and total soluble solids (B) in the pulp of durian (Durio zibethinus Murr.) cv. Chanee fruit during ripening at 25 C. Treatments are controls ( ), ethephon (D), 1-MCP (*) and 1-MCP + ethephon (~). Data are means of six replications, each containing 3 fruit. LSD is indicated by a bar.
20
3. Results 3.1. Firmness, TSS and colour During ripening at 25 C, pulp firmness of the controls decreased rapidly from day 2 (Fig. 1). The same was found in ethephon-treated fruit. Treatment with 1-MCP prevented the decrease in firmness for 6-7 days of ripening at 25 C (Fig. 1A). However, between day 7 and 9 a decrease in firmness was found in this fruit which was similar to the rate found in the controls during day 2–5 (Fig. 1A). In fruit treated with 1-MCP and ethephon, pulp firmness was not affected for 3–4 days, then decreased rapidly from day 5 onward (Fig. 1A). Controls showed an increase in TSS, which was delayed by 1-MCP treatment, while ethephon had no effect (Fig. 1B). At harvest the pulp colour was light cream. After 4 days of storage at 25 C the pulp was dark yellow. In controls the L* value (Fig. 2A) and hue value (Fig. 2C) of the pulp decreased while the b* value (Fig. 2B) increased. These effects were delayed by the 1-MCP treatment and were not affected by the ethephon treatment. 3.2. Respiration and ethylene production rates The respiration rate (carbon dioxide production) of the whole control fruit increased from day 0 to 5 of storage at 25 C (Fig. 3A). Ethephon had no effect on respiration (Fig. 3A). 1-MCP delayed the increase in respiration rate by about 6 days (Fig. 3A). The ethylene production rate of the controls increased throughout the 9 days of storage at 25 C (Fig. 3B). Until day 6
Ethylene production (μl C2H4 kg-1 h-1) Carbon dioxide production (mg CO 2 kg-1 h-1)
A. Wisutiamonkul et al. / Postharvest Biology and Technology 110 (2015) 18–23
400
A
350
LSD0.05 = 28.0
300
250 200 150 100 50 0
B 30
LSD0.05 = 2.85
25 20
15 10
5 0
0
100
A
L* value
95
85 80
70
B 50
b* value
3
4
5
6
7
8
9
Fig. 3. Respiration (A) and ethylene production (B) of durian (Durio zibethinus Murr.) cv. Chanee fruit during ripening at 25 C. Treatment are controls ( ), ethephon (D), 1-MCP (*) and 1-MCP + ethephon (~). Data are means of six replications, each containing 3 fruit. LSD is indicated by a bar.
75
LSD0.05 = 1.74
45
this increase was inhibited by 1-MCP. The ethephon treatment increased the amount of measured ethylene, with a large effect during day 1–3. In fruit treated with 1-MCP and ethephon, ethylene production was still higher than the control fruit but was less than the ethephon-treated fruit (Fig. 3B). 3.3. Carotenoids
40
As described by Wisutiamonkul et al. (2015), the pulp
a-carotene concentration at mature harvesting accounted for about 20% of total carotenoids, and b-carotene for about 80%
35 30
C LSD0.05 = 0.50
95
Hue value
2
Days after treatment
LSD0.05 = 1.33
90
1
90
85 80 0
1
2
3 4 5 6 Days after treatment
7
8
9
Fig. 2. L* (A), b* (B) and hue angle (C) values in the pulp of durian (Durio zibethinus Murr.) cv. Chanee fruit during ripening at 25 C. Treatments are controls ( ), ethephon (D), 1-MCP (*) and 1-MCP + ethephon (~). Data are means of six replications, each containing 3 fruit. LSD is indicated by a bar.
(Fig. 4). The xanthophylls lutein and zeaxanthin were present in small concentrations (Fig. 4). A fifth carotenoid could not be identified. The data showed very low levels of this compound in the controls, with a HPLC peak just before the peak of a-carotene (data not shown). During storage until the stage where the fruit was ready to eat, total carotenoids in the pulp of control fruit increased by a factor of about 2.5 (Fig. 4A). This increase was very largely due to increased concentrations of pulp a-carotene and b-carotene (Fig. 4B, C). The a-carotene concentration increased by 32% and the b-carotene concentration by 36%. Concentrations of zeaxanthin also increased during storage (Fig. 4E), while those of lutein were not statistically different from controls (Fig. 4D). Treatment with ethephon did not affect the total carotenoid concentrations (Fig. 4A). 1-MCP treatment prevented the increase in a- and b-carotene concentrations (Fig. 4B, C), although a late (day 4–9) increase was observed in the b-carotene concentration
A. Wisutiamonkul et al. / Postharvest Biology and Technology 110 (2015) 18–23
40
a a
b b
20
b b
0.20
A
a a
a ab b b
30
b b
D
10 LSD0.05 = 0.58
7
a a
a a
a a
a a
6
5
b b
b b
b b
b b
C 35
LSD0.05 = 3.48
30
a a
a a
a a
b b
b b
b b
15
0
1
2
3
4
5
6
LSD0.05 = 0.036
0.16
0.14 0.12
E
2.0
LSD0.05 = 0.8
1.5
1.0 0.5 0.0 0
1
2
7
8
a a
a a
a a
b b
b b
b b
3
4
5
a a
a ab b b
b c 6
7
8
9
Days after treatment
a ab b b
25 20
0.18
0.10
B
8
4
β-Carotene (μg g-1 FW)
a a
Lutein (μg g-1 FW)
LSD0.05 = 4.42
Zeaxanthin (ng g-1 FW)
α-Carotene (μg g-1 FW)
Total carotenoids (μg g-1 FW)
50
21
9
Days after treatment Fig. 4. Total carotenoid concentrations (A), and the concentrations of a-carotene (B), b-carotene (C), lutein (D), and zeaxanthin (E) in the pulp of durian (Durio zibethinus Murr.) cv. Chanee fruit during ripening at 25 C. Treatment are controls ( ), ethephon (D), 1-MCP (*) and 1-MCP + ethephon (~). Data are means of six replications, each containing 3 fruit. LSD is indicated by a bar. Data in (A)–(E) were compared on various harvest dates, with a different combination of letters showing statistical difference at P 0.05 by DMRT; data in (D) showed no differences.
of 1-MCP-treated fruit (Fig. 4C). 1-MCP also delayed the increase in zeaxanthin concentrations (Fig. 4E). Although 1-MCP seemed to largely prevent the increase in lutein concentrations, no statistically significant differences were found between single harvest times (Fig. 4D). It should be noted that after the 1-MCP treatment total carotenoid concentrations showed an increase between day 0 and 3–4 (Fig. 4A). This increase was not accounted for by the sum of the four individual carotenoids determined (compare Fig. 4A with B–E). Similarly in fruit treated with 1-MCP and ethephon, treatment did not affect significantly total carotenoids, and both minor and major carotenoids (Fig. 4). Correlation coefficients of a-carotene concentrations with objective colour values L*, hue and b* were 0.80, 0.74, and 0.73, respectively, and of the b-carotene concentration 0.87, 0.81, and 0.84, respectively (Table 1). With the exception of the lutein concentrations, all parameters measured in the present study showed high correlation coefficients (Table 1).
4. Discussion 1-MCP prevented, at least initially, the increase in a- and b-carotene concentrations, as well as in zeaxanthin concentrations, showing that these were regulated by endogenous ethylene. Similarly, 1-MCP inhibited the increase in the rates of respiration and ethylene production, and the decrease in pulp firmness. The data therefore indicate that the carotenoid accumulation at a late stage of ripening is an integral part of the ethylene-regulated ripening processes. These data are confirmed by the finding that the increase in fruit ethylene production preceded a- and b-carotene accumulation. The change in pulp colour was correlated in time with the increase in a-carotene and b-carotene concentrations. Additionally, 1-MCP inhibited pulp yellowing. The data therefore suggest that a-carotene and b-carotene were the cause of the increase in yellowness during ripening. Positive b* values, and lower hue
Table 1 Pearson’s correlation (r) comparing relatively between physiological and chemical measurements in durian (Durio zibethinus Murr.) cv. Chanee pulp during ripening at 25 C. Pearson’s correlation Total carotenoids a-Carotene b-Carotene Lutein Zeaxanthin L* value b* Value Hue value No star = non-significant. * P 0.05. *** P 0.001.
Total carotenoids – 0.74*** 0.72*** 0.24 0.80*** 0.80*** 0.77*** 0.87***
a-Carotene
b-Carotene
Lutein
Zeaxanthin
L* value
b* Value
Hue value
– 0.84*** 0.44* 0.77*** 0.80*** 0.73*** 0.74***
– 0.34 0.87*** 0.87*** 0.84*** 0.81***
– 0.39* 0.05 0.03 0.00
– 0.80*** 0.76*** 0.75***
– 0.96*** 0.95***
– 0.95***
–
22
A. Wisutiamonkul et al. / Postharvest Biology and Technology 110 (2015) 18–23
angles describe the intensity of the yellow colour, while the L* values describe lightness (Selahle et al., 2015). We found high correlation coefficients between a- and b-carotene concentrations with L*, hue and b*. Similarly, in mango fruit flesh the b-carotene concentration was positively correlated with yellowness, and was also correlated with the Hunter a* and L* values (Ornelas-Paz et al., 2008) and in sweet peper b-carotene concentrations showed a correlation with the hue and b* values (Selahle et al., 2015). In other fruit an increase in b-carotene concentrations in flesh/pulp during the postharvest phase has been reported. For example, in mango that ripened for 8 days at 18–19 C a small increase in fruit flesh b-carotene concentration was found (Vásquez-Caicedo et al., 2006) whilst in mango fruit stored for 16 days at 28 C the concentration of b-carotene in the fruit flesh considerably increased (Ornelas-Paz et al., 2008). In mandarin (Citrus unshiu) fruit stored at 5 , 20 , or 30 C for 21 days, the b-carotene concentration in fruit flesh (juice sacs) increased at 20 and 30 C, while no effect was found at 5 C (Matsumoto et al., 2009). Increased concentration were also reported in winter squash (Cucurbita maxima), stored at 20 C (Arvayo-Ortiz et al., 1994) and in sweet pepper stored for 21 days at 7.5 C and for 3 days at 20 C (Selahle et al., 2015). By contrast, tomato fruit stored for 21 days in the dark at 12–14 C showed no change in fruit flesh b-carotene concentration (Liu et al., 2009). Storage of kumquat (Fortunella japonica) fruit for 21 days at 17 C also had no effect on the levels of b-carotene (Schirra et al., 2008). Apart from our previous paper (Wisutiamonkul et al., 2015) and the more detailed data shown now, no reports apparently have been published on changes in a-carotene concentrations in fruit flesh after harvest. In other fruit the zeaxanthin concentration reportedly increased or remained stable. For example in mandarin (C. unshiu) stored at 5 , 20 , or 30 C for 21 days, zeaxanthin concentrations increased early at 30 C, and later at 20 C. No change was found at 5 C (Matsumoto et al., 2009). Storage of kumquat (Fortunella japonica) fruit for 21 days at 17 C had no effect on zeaxanthin (Schirra et al., 2008). Very little seems reported on lutein concentrations. During the experiment of Schirra et al. (2008) on kumquat storage the lutein concentration decreased. Ethephon has been widely used as a replacement for ethylene treatment in agriculture (Abeles et al., 1992). Treatment with ethephon, thus with exogenous ethylene, did not affect the parameters studied with the exception of an increase in the amount of measured ethylene, and a very small hastening effect on firmness decrease. The increase in the measured ethylene detected in ethephon-treated fruit may not be due to an increase in endogenous ethylene production, but it could be due to the release of ethylene from ethephon (Yang, 1969), thus making the difference between the control (not treated) and the treated fruit. As shown in the Introduction, the ethephon treatment is used in practice to ensure full and rapid ripening of fruit that is harvested too early, whereby this can be a matter of only a few days. Ketsa and Daengkanit (1999) showed large differences in ethylene production, and cell wall hydrolase activities in fruit harvested at 102 and 109 days after anthesis, showing that a week difference in harvest has a large impact on the rate of ripening. The very small effect of ethephon on the parameters studied with the exception of an increase in the amount of measured ethylene in the present experiments means that the fruit was harvested at a relatively advanced stage, showing a full complement of endogenous ethylene production, and stimulated ripening processes. Our results show that endogenous ethylene regulates the accumulation of a- and b-carotene in durian pulp. The same (although only for b-carotene) apparently has only been reported previously in papaya fruit (Fabi et al., 2007). Regulation of a-carotene accumulation by endogenous ethylene seemingly has not been reported before.
It is concluded that a- and b-carotene accumulation during postharvest ripening is regulated by endogenous ethylene. The highest a- and b carotene concentrations are found in fruit that was ready for consumption (by day 5-9 of storage in the present experiments). Furthermore, the early small increase in zeaxanthin concentrations was regulated by endogenous ethylene. The data suggested that the increase in carotenoid concentrations is an ethylene-regulated ripening process in pulp of durian fruit. Acknowledgements The research was financially supported by the Royal Golden Jubilee PhD Program (PHD/0021/2553) of the Thailand Research Fund (TRF), Kasetsart University and the Higher Education Commission, Ministry of Education, Thailand. References Abeles, F.B., Morgan, P.W., Saltveit, M.E., 1992. Ethylene in Plant Biology. Academic Press Inc., San Diego. Amornputti, S., Ketsa, S., van Doorn, W.G., 2014. Effect of 1-methylcyclopropene (1MCP) on storage life of durian fruit. Postharvest Biol. Technol. 97, 111–114. Arvayo-Ortiz, R.M., Garza-Ortega, S., Yahia, E.M., 1994. Postharvest response of winter squash to hot-water treatment, temperature, and length of storage. HortTechnology 4, 253–255. Blankenship, S., Dole, J.M., 2003. 1-Methylcyclopropene: a review. Postharvest Biol. Technol. 28, 1–25. Cheyglinted, S., 1993. Effect of ethephon on the physio-chemical changes during the ripening of ‘Chanee’ durian (Durio zibethinus Murray) harvested at different maturity stages. MS Thesis. Los Banos College, The Philippines. Deaquiz, Y.A., Álvarez-Herrera, J., Fischer, G., 2014. Ethylene and 1-MCP affect the postharvest behavior of yellow pitahaya fruits (Selenicereus megalanthus Haw.). Agron. Colomb. 32, 44–51. Fabi, J.P., Cordenunsi, B.R., de Mattos Barreto, G.P., Mercadante, A.Z., Lajolo, F.M., Oliveira do Nascimento, J.R., 2007. Papaya fruit ripening: response to ethylene and 1-methylcyclopropene (1-MCP). J. Agric. Food Chem. 55, 6118–6123. Jiang, Y., Joyce, D.C., Macnish, A.J., 1999. Extension of the shelf life of banana fruit by 1-methylcyclopropene in combination with polyethylene bags. Postharvest Biol. Technol. 16, 187–193. Ketsa, S., Daengkanit, T., 1999. Firmness and activities of polygalacturonase, pectinesterase, b-galactosidase and cellulase in ripening durian harvested at different stages of maturity. Sci. Hortic. 80, 181–188. Ketsa, S., Pongkool, S., 1995. Effect of maturity stages and ethylene treatment on ripening of durian fruits. In: Frisinia, C., Mason, K., Faragher, J. (Eds.), Proceedings of Australasian Postharvest Horticulture Conference. Science and Technology for Fresh Food Revolution, Melbourne, Australia, pp. 67–72. Liu, L.H., Zabaras, D., Bennett, L.E., Aguas, P., Woonton, B.W., 2009. Effects of UV-C, red light and sun light on the carotenoid content and physical qualities of tomatoes during post-harvest storage. Food Chem. 115, 495–500. Maninang, J.S., Wongs-Aree, C., Kanlayanarat, S., Sugaya, S., Gemma, H., 2011. Influence of maturity and postharvest treatment on the volatile profile and physiological properties of the durian (Durio zibethinus Murray) fruit. Int. Food Res. J. 18, 1067–1075. Marty, I., Bureau, S., Sarkissian, G., Gouble, B., Audergon, J.M., Albagnac, G., 2005. Ethylene regulation of carotenoid accumulation and carotenogenic gene expression in colour-contrasted apricot varieties (Prunus armeniaca). J. Exp. Bot. 56, 1877–1886. Matsumoto, H., Ikoma, Y., Kato, M., Nakajima, N., Hasegawa, Y., 2009. Effect of postharvest temperature and ethylene on carotenoid accumulation in the flavedo and juice sacs of Satsuma mandarin (Citrus unshiu Marc.) fruit. J. Agric. Food Chem. 57, 4724–4732. Moretti, C.L., Araujo, A.L., Marouelli, W.A., Silva, W.L.C., 2002. 1-Methylcyclopropene delays tomato fruit ripening. Hortic. Brasil 20, 659–663. Ornelas-Paz, J.D.J., Yahia, E.M., Gardea, A.A., 2008. Changes in external and internal color during postharvest ripening of ‘Manila’ and ‘Ataulfo’ mango fruit and relationship with carotenoid content determined by liquid chromatography– APcl*-time-of-flight mass spectrometry. Postharvest Biol. Technol. 50, 145–152. Palapol, Y., Kunyamee, S., Thongkhum, M., Ketsa, S., Ferguson, I.B., van Doorn, W.G., 2015. Expression of expansin genes in the pulp and the dehiscence zone of ripening durian (Durio zibethinus) fruit. J. Plant Physiol. 182, 33–39. Paull, R.E., Ketsa, S., 2014. Durian: postharvest quality-maintenance guidelines. Cooperative Extension. University of Hawaii at Manoa. http://www.ctahr. hawaii.edu/oc/freepubs/pdf/F_N-27.pdf. Schirra, M., Palma, A., D'Aquino, S., Angioni, A., Minello, E.V., Melis, M., Cabras, P., 2008. Influence of postharvest hot water treatment on nutritional and functional properties of kumquat (Fortunella japonica Lour. Swingle, cv. Ovale) fruit. J. Agric. Food Chem. 56, 455–460. Selahle, K.M., Sivakumar, D., Jifon, J., Soundy, P., 2015. Postharvest responses of red and yellow sweet peppers grown under photo-selective nets. Food Chem. 173, 951–956.
A. Wisutiamonkul et al. / Postharvest Biology and Technology 110 (2015) 18–23 Vásquez-Caicedo, A.L., Heller, A., Neidhart, S., Carle, R., et al., 2006. Chromoplast morphology and b-carotene accumulation during postharvest ripening of mango cv. ‘Tommy Atkins’. J. Agric. Food Chem. 54, 5769–5776. Watkins, C.B., 2006. The use of 1-methylcyclopropene (1-MCP) on fruits and vegetables. Biotechnol. Adv. 24, 389–409. Wei, X., Chen, C., Yu, Q., Gady, A., Yu, Y., Liang, G., Gmitter, F.G., 2014. Comparison of carotenoid accumulation and biosynthetic gene expression between Valencia and Rohde Red Valencia sweet oranges. Plant Sci. 227, 28–36.
23
Wisutiamonkul, A., Promdang, S., Ketsa, S., van Doorn, W.G., 2015. Carotenoids in durian fruit pulp during growth and postharvest ripening. Food Chem. 180, 301– 305. Yang, S.F., 1969. Ethylene evolution from 2-chloroethylphosphonic acid. Plant Physiol. 44, 1203–1204. Ziliotto, F., Begheldo, M., Rasori, A., Bonghi, C., Tonutti, P., 2008. Transcriptome profiling of ripening nectarine (Prunus persica L. Batsch) fruit treated with 1MCP. J. Exp. Bot. 59, 2781–2791.