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Postharvest Biology and Technology 91 (2014) 128–133

Contents lists available at ScienceDirect

Postharvest Biology and Technology

journa l h om epa ge : www.elsev ier .com/ locate /postharvbio

mproved management of mango fruit though orchard andackinghouse treatments to reduce lenticel discoloration andrevent decay

. Feygenberga,1, A. Keinanb,1, I. Kobilera, E. Falika, E. Pesisa, A. Lersa, D. Pruskya,∗

Department of Postharvest Science of Fresh Produce, The Volcani Center, Bet Dagan 50250, IsraelTzemach Subtropical Experimental Station, Emek Hayarden 1510501, Israel

r t i c l e i n f o

rticle history:eceived 5 November 2013ccepted 4 January 2014

eywords:ostharvest managementot water brushingot water spray

a b s t r a c t

Mango fruit are exposed to complex postharvest handling management, intended to improve postharvestquality retention during export shipment. Susceptibility to lenticel discoloration and to Alternaria siderots and Phomopsis stem-end rot under current handling conditions led us to re-evaluate and modify thechain of postharvest treatments, from the orchard to the packinghouse. The previously developed hot-water brushing (HWB) treatment was found effective in reducing incidence of Alternaria and stem-endrots, but it significantly induced development of red lenticels. Two factors were key to improving fruitquality, by simultaneously reducing lenticel discoloration and decay development: (a) postharvest water

lternaria rottem end rotreharvest treatments

and/or NaOH washes in the orchard, and (b) hot-water spray (HWS) applied over rollers without brushesin the packinghouse. The present results indicate that optimal management involves combinations ofwater washes in the orchard with packinghouse HWS treatment; this significantly reduced the severity oflenticel discoloration by 50–60%, and the incidence and extent of postharvest side rots caused by Alternariaby 60% or more. These results indicate that appropriate handling of fruit can appreciably improve theirquality during prolonged storage and shipment.

. Introduction

Mango is a tropical/subtropical fruit, of high and significant eco-omic importance. The storage life-time of mangoes is limited to–4 weeks at 10–15 ◦C (Prusky et al., 1999; Brecht et al., 2010).igh-quality fruit should be free of external damage, bruises, latexr sap injury, and decay. According to Kader and Mitcham (2008),uality acceptability of mangoes depends largely on external and

nternal quality parameters. Preharvest and postharvest practices,nd packinghouse management contribute greatly to retention ofruit external quality, both in Israel and throughout the worldwideupply chain (Prusky et al., 1999; Kader, 2008), and thus to ensur-ng that the fruit reaching the consumers retain the optimal qualityttributes (Kader, 2008).

Mango losses after harvest are primarily due to: harvesting atnappropriate maturity stages; mechanical damage caused during

arvesting or improper field handling; sap burn; discoloration of

enticels; fruit softening; decay; chilling injury; and/or disease andest damage (Yahia, 2006). In Israel, impaired quality after harvest

∗ Corresponding author. Tel.: +972 506 220080; fax: +972 3 9683622.E-mail address: dovprusk@agri.gov.il (D. Prusky).

1 These authors contributed equally to the work.

925-5214/$ – see front matter © 2014 Elsevier B.V. All rights reserved.ttp://dx.doi.org/10.1016/j.postharvbio.2014.01.001

© 2014 Elsevier B.V. All rights reserved.

results mainly from postharvest diseases (Prusky et al., 1981, 1983,2002) and external blemishes such as lenticel spotting (Pesis et al.,2000). Quality losses often occur because of incorrect transport andinadequate handling in the field and in the packinghouse, and thisis the subject of the present paper.

In Israel, mangoes are harvested manually, directly into large300 kg bins or 30 kg harvesting racks. Fruit can be picked with anapproximately 5 cm petiole, in order to prevent spurting of resinoussap, though are usually are picked with a 0.5 cm petiole. Sap injuryor skin burn affects fruit quality by spoiling skin color and pro-moting decay development. Mango sap leakage and its negativeeffects are reduced by various methods, as suggested by Holmesand Ledger (1992); the one adopted in Israel includes a 30 s dip in2% NaOH, applied in the orchard before the fruit is transferred tothe packinghouse.

Postharvest diseases reduce fruit quality and result in severelosses (Prusky, 1996). In Israel the main postharvest disease isAlternaria black spot, caused by the fungus Alternaria alternata,which penetrates the fruit during its growth, and is affected by therelative humidity in the orchard (Kobiler et al., 2001; Prusky et al.,

2001). Following infection, the fungus remains quiescent until fruitharvest and ripening (Droby et al., 1986, 1987). Stem-end rots thatoccur during long periods of storage are caused mainly by Phomop-sis mangifera (Kobiler et al., 2001; Davidzon et al., 2009).

ology and Technology 91 (2014) 128–133 129

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In Israel, control of postharvest development of side and stem-nd rots has been achieved by adopting a series of postharvestanagement practices that include hot water brushing (HWB) for

5–20 s, followed by application of prochloraz (a.i., Sportak 45%t 125 mg mL−1) in 50 mM HCl, and waxing with a polyethylenemulsion. This treatment enables commercially successful storaget 12 ◦C for 3–4 weeks and ripening at 20 ◦C for an additional weekPrusky et al., 1999).

Lenticel discoloration is a superficial blemish that affects someultivars: it imparts a speckled appearance to the fruit, which thenre regarded as less desirable, and are downgraded, despite theact that the speckled appearance does not affect the internal qual-ty. Blemish development is limited to the lenticel perimeter andhe immediately adjacent area, and does not extend deeper thanhe outermost layers of the rind (Du Plooy et al., 2009). The newlyeveloped Israeli cultivars, led by cv. Shelly (Lavi et al., 1997), asell as the traditionally grown cultivars such as Keitt (Prusky et al.,

002) have shown increased sensitivity to external handling con-itions, with enhanced incidence of lenticel discoloration duringtorage (Prusky, personal observation). For this reason the posthar-est treatments of mango fruit, including management of field andackinghouse treatments, were re-evaluated. The objective of theresent study was to reduce (i) the incidence of red and black lenti-el discoloration, and (ii) postharvest diseases, by improving theanagement of postharvest orchard and packinghouse treatments,

n order to improve fruit quality during shipment and delivery ofhe fruit to foreign markets.

. Materials and methods

.1. Fruit material and storage conditions

Freshly harvested mango (Mangifera indica L.) fruit, cvs. Shellynd Keitt were obtained from trees in commercial orchards in Israelnd subjected to several experimental treatments in each of threeonsecutive years. The results obtained in the various years wereimilar, therefore those from only one year are presented. Eachreatment comprised six replications, each usually of 15 fruit.

The fruit were harvested at the commercial mature green stage,ith at least 12% TSS and a yellow pulp color (ranging from light

o yolk yellow) (see harvesting standards Plant Protection andnspection Services, PPIS – http://www.moag.gov.il/PPISENG/). Theruit were treated on the day of harvest or the following day, andransferred to simulated export conditions: they were stored forbout 5 weeks (depending on the experiment) at 12 ◦C, RH about0% and then stored at 20 ◦C and RH 85% to simulate ripening on

retail shelf. Control untreated fruit were stored under the sameonditions immediately following arrival from the orchard.

.2. Postharvest orchard treatments in semicommercial mangoxperiments

Fruit were harvested into bins containing approximately 300 kg790–800 fruit) that were dipped in a tank of either water or variousoncentrations of NaOH (0.1–2.0%) for 30 s, in the orchard. The binsere then drained and kept in the shade until transfer to the pack-

nghouse, within 3–4 h, for further treatment. In some cases theins were dipped in the packinghouse immediately after arrival. Aample of 15 fruit was taken from each of the six 300 kg bins (totalf 90 fruit) for further evaluation.

.3. Postharvest packinghouse treatments in semicommercial

ango experiments

Postharvest treatments were carried out at the Department ofostharvest Science in the Volcani Center at Bet Dagan, and at the

Fig. 1. Diagram of the (A) hot water brush and (B) hot water spray.

Tzemach and Shoham packinghouses. In all cases the treatmentpatterns were similar: HWB at 55 ◦C was applied on the packing lineas a spray at 100–120 L min−1 and a nozzle pressure of 2 atm (about200 kPa) above cylindrical brushes revolving at 70 revolutions/min(rpm) (Prusky et al., 1999). Fruit were passed over five to seven(according to the packing line) transversely mounted, 12 cm diam-eter plastic brushes for 15–20 s.

An improved hot water spray (HWS) treatment was developedin which the revolving brushes of the hot water treatment in thepacking line were replaced with simple revolving stainless-steelrollers (Fig. 1).

Acid prochloraz, comprising Prochloraz (Sportak, 45% a.i.;AgrEvo UK, Ltd, Hauxton, Cambridge, England) at 125 �g mL−1 in50 mM hydrochloric acid, was sprayed over the packing lines afterthe HWB treatment (Prusky et al., 1999). Finally, the fruit werewaxed with polyethylene emulsion wax containing 12% (v/v) sol-uble solids (Safepack, Israel), applied over brushes according tocommercial practice.

2.4. Fruit ripening, development of red and black lenticels, blackspots and stem-end rots during storage

Disease severity, expressed as the percentage of fruit surfacecovered by black lesions, was assessed by visually comparing theactual decayed region of the fruit with a printed scale showingfruit with various percentages of covered areas, ranging from 0to 100%, simulating Alternaria decay (Prusky et al., 2001, 2002).Disease evaluation was applied to 90 fruit (15 from each of six repli-cates) immediately following their transfer to 20 ◦C from storage at12 ◦C, and then periodically until most of the fruit were ripe. Fruitwere regarded as unmarketable when more than 1% of their sur-face area exhibited black spots of decay. Stem-end decay symptomsmeasuring 0.5 cm were regarded as positive incidence of stem-enddecay.

Lenticel spotting was assessed visually according to a 0–3 scalethat took into account both the strength of discoloration of lenticelsand the area covered by the symptoms. The scale used for lenticelevaluation was based on transformation of the directly evaluated

percentage area covered by discolored lenticels, to a scale of dis-crete values ranging from 0 to 3. Values of 0 were assigned topercentages of discolored lenticel areas ranging from 0 to 10% (allof which are marketable). A value of 1 was assigned to fruit with

1 ology and Technology 91 (2014) 128–133

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Fig. 2. Effects of HWB treatment after various intervals following pedicel detach-ment, on red and black discoloration of lenticels of mango fruit cv. Shelly. Eachvalue represents the mean of six replicates, each of 15 fruit. Average discoloration

greatly: HWB treatment increased red discoloration of lenticelsof mango fruit cv. Shelly, dipped in water or 0.1% NaOH by 19-or 5.3-fold, respectively, compared with that on unbrushed fruit.

Table 2Effects of orchard washes followed by packinghouse HWB treatment on the inci-dence of red and black lenticel discoloration on mango fruit cv. Shelly. Mango fruitwere dipped in water or 0.1% NaOH for 30 s in the orchard and then transferred to

30 O. Feygenberg et al. / Postharvest Bi

iscolored lenticels covering 10–40% of the fruit surface area; aalue of 2 to those with discolored lenticels covering 40–70% ofheir surface area; and a value of 3 to those with lenticels covering

ore than 70% of their surface area. The percentage of area coveredith discolored lenticels was determined as described previously

or Alternaria rot (Prusky et al., 2001, 2002). Strength of discol-ration was included in the scale by adding decimal values (0.3,.6, and 0.9) to the integral values of the scale, as determined fromhe discolored lenticel area.

.5. Statistical analysis

All the experiments were designed as fully randomized. Eachreatment was applied to six independent bins of fruit (i.e., sixeplications). From each bin 15 fruit were randomly sampled forvaluation. Experiments were repeated at least once during eachf three consecutive years. One-way analysis of variance (ANOVA)nd Tukey’s HSD pairwise comparison tests at P < 0.05, were appliedy means of the JMP statistical software program, version 7 (SASnstitute Inc., Cary, NC, USA).

. Results

.1. Effect of orchard treatment on the incidence of red and blackenticels on mango

The analysis of mango fruit management at harvest and of itsffect on lenticel discoloration was carried out by comparing theffects of washing the fruit in various solutions immediately afterarvest, and then transferring them to storage at 12 ◦C without anyther postharvest treatments (Table 1). Fruit washing with NaOHt 0.1, 1, or 2% in water reduced the percentage of red and blackenticels by factors of 4–6. The highest reduction in severity ofed lenticels, by almost 83%, was obtained by simple water wash-ng. Washing with NaOH at any concentration reduced the averageeverity of red and black lenticels by about 68 and 63%, respectively,ompared with untreated fruit, but this was not significantly dif-erent from the effect of water washing. This suggests that washingf freshly harvested fruit might improve fruit quality by reducingenticel discoloration.

.2. Effects of hot water brushing on the incidence of lenticeliscoloration

The time-variation of the importance of the effect on fruit qual-ty of postharvest sap spreading was determined in mango fruit cv.helly harvested with a long (10–15 cm) pedicel. The pedicel was

etached, sap was allowed to spread over the fruit and after 0, 0.5,, 2, or 16 h following stem detachment the fruit were subjectedo HWB treatment at 55 ◦C (Fig. 2). Analysis of the occurrence ofed lenticel discoloration 15 days after the HWB treatment showed

able 1ffects of orchard treatments on the incidence of red and black lenticel spotting inango fruit cv. Shelly. Mango fruit were dipped in water or various concentrations

f NaOH for 30 s, in the orchard. Fruit were stored without postharvest treatment for weeks at 12 ◦C (end of storage). Each value represents the mean of six replicates,ach of 15 fruit. Average values within columns followed by unlike letters differignificantly at P < 0.05 according to the Tukey-Kramer HSD Test.

Postharvest treatmentsin the orchard

Red lenticels(index 0–3)

Black lenticels(index 0–3)

No washing 1.45a 1.35aH2O 0.25b 0.62b0.1% NaOH 0.51b 0.53b1.0% NaOH 0.39b 0.38b2.0% NaOH 0.56b 0.31b

indexes for red (lower case) or black (capital case) lenticels with unlike letters differsignificantly at P < 0.05, according to the Tukey-Kramer HSD Test.

that symptoms in fruit that had undergone the brushing treatmentwere 3.4 times as strong as those in unbrushed fruit. This differ-ence persisted in brushed fruit up to 16 h after pedicel detachment(Fig. 1).

Black-lenticel discoloration symptoms caused by sap spread-ing on the fruit were reduced by a factor of 4.3 – to an index of0.25 compared with 1.07 in untreated fruit – when the HWB treat-ment was applied immediately after pedicel detachment. However,the black-lenticel incidence index increased to 1.2, similar to the1.07 in untreated fruit, if the brushing was applied 16 h after stemdetachment (Fig. 2).

3.3. Effects of the combination of orchard and packinghousetreatments on the severity of black and red lenticel discolorationin mango fruit cv. Shelly

Postharvest washing of mango fruit with water in the orchard,with no subsequent packinghouse treatment, reduced red-lenticelincidence almost three times as effectively as dipping in 0.1% NaOH(Table 2). However, if either of the orchard treatments was followedby HWB at 55 ◦C, severity of red discoloration of lenticels increased

the packinghouse for HWB treatment and waxing. The fruit were then stored for 5weeks at 12 ◦C (end of storage). Between columns, average values followed by unlikelower-case letters differ significantly at P < 0.05, according to the Tukey-Kramer HSDTest, indicating significant difference between orchard treatments. Within columns,average values followed by unlike capital letter differ significantly at P < 0.05 accord-ing to the Tukey-Kramer HSD Test, indicating significant differences induced bypackinghouse treatments.

Red-lenticel discoloration(index 0–3)

H2O NaOH 0.1%

Orchard treatment only 0.12b, A 0.39a, AOrchard treatment + packinghouse HWB 2.29a, B 2.08a, B

Black lenticelsdiscoloration (index 0–3)

H2O NaOH 0.1%

Orchard treatment only 0.21a, A 0.27a, AOrchard treatment + packinghouse HWB 0.10a, B 0.06a, B

O. Feygenberg et al. / Postharvest Biology a

Table 3Effects of orchard washes followed by HWB or HWS packinghouse management onthe incidence of lenticel discoloration on mango fruit cv. Keitt. Mango fruit were diptreated with water or with NaOH at 0.1 or 1% in the orchard and then transferred tothe packinghouse for HWB or HWS treatment and waxing. They were then storedfor 35 days at 12 ◦C (end of storage). Between columns, average values followedby unlike lower-case letters differ significantly at P < 0.05, according to the Tukey-Kramer HSD Test, indicating significant differences between orchard treatments.Within columns, average values followed by unlike capital letters differ significantlyat P < 0.05, according to the Tukey-Kramer HSD Test, indicating differences inducedby packinghouse treatments.

Orchard H2O 0.1% NaOH 1% NaOH

Red lenticel discoloration (index 0–3)PackinghouseHWB 1.16a,A 1.01a,A 0.93a,AHWS 0.50a,B 0.35a,B 0.34a,B

Black lenticel discoloration (index 0–3)Packinghouse

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hese results clearly indicate that packinghouse HWB treatmentignificantly increased red discoloration of lenticels.

Similarly, water-dip treatment of fruit in the orchard was almost8% more effective than NaOH treatment in reducing incidence oflack discoloration of lenticels caused by sap spreading (Table 2).owever, in this case the packinghouse HWB treatment further

educed black-lenticel incidence, following either water or NaOHreatment, which suggests that black-lenticel symptoms caused byap spreading were actually reduced by washing the fruit in theackinghouse.

.4. Effects of the combination of postharvest orchard treatmentsnd packinghouse HWB or HWS treatments on the incidence oflack and red discoloration of lenticels in mango fruit cv. Keitt

Orchard treatment of mango fruit cv. Keitt with water or with.1 or 1% NaOH, followed by packinghouse HWB treatment at 55 ◦Clicited similar incidences of red discoloration of lenticels, withndexes ranging from 0.93 to 1.16 after 35 days of storage at 12 ◦CTable 3). However, if the hot-water brushing treatment in theackinghouse was replaced with hot-water spraying at 55 ◦C the

ncidence of red-lenticel symptoms declined by 50–65% to an indexanging from 0.34 to 0.50 (Table 3).

The combination of orchard washes and packinghouse treat-ents elicited similar effects on the incidence of black-lenticel

ymptoms to those on red-lenticel symptoms (Table 3). Incidence oflack discoloration of lenticels during storage did not differ amongruit that were washed with either water or various concentrationsf NaOH: the average index ranged from 0.54 to 0.69. However,

able 4ffects of orchard washes followed by packinghouse HWB or HWS treatments on the inci

Orchard treatment H2O 0.1% NaOH

End of storage Alternaria rots (%) Stem end rots (%) Alternaria r

Untreated 26.3a 38.6a 20.8a

Packinghouse HWB 2.36b 6.2b 5.88b

Packinghouse HWS 0.10b 10.0b 0.10c

Orchard treatment H2O 0.1% NaOH

End of shelf life Alternaria rots (%) Stem end rots (%) Alternaria r

Untreated 35.9a 60.0a 20.7a

Packinghouse HWB 10.2b 12.4b 15.4a

Packinghouse HWS 10.0b 20.0b 0.10c

ruits were stored at 12 ◦C for 35 days (end of storage) and then at 20 ◦C for 5 days (shelft P < 0.05, according to the Tukey-Kramer HSD Test.

nd Technology 91 (2014) 128–133 131

HWS treatment in the packinghouse, following the water or NaOHtreatment in the orchard, reduced black discoloration of lenticelsby about 25–53%, no matter which treatment was applied in thefield.

Prusky et al. (1999) initially considered that HWB, which inte-grated hot water spraying and brushing into a single mangotreatment, would be a key means for postharvest reduction of bothAlternaria side rot and Phomopsis stem-end rot (Table 4), follow-ing long-term storage at 12 ◦C. Dipping in water or in 0.1 or 1%NaOH in the orchard, followed by HWB treatment in the pack-inghouse reduced the incidence of Alternaria side rots by 90, 72,or 96%, respectively. However, the reduction of the Alternaria rotwhen HWS treatment was applied following the orchard washes,ranged from 96 to 98%, suggesting that HWS treatment was bet-ter able to control Alternaria rot development than HWB treatment(Table 4). The enhanced capability of the HWS treatment to reduceAlternaria rot was mainly observed following shelf-life at 20 ◦C,whereas NaOH-treated fruit showed a significant delay in the inci-dence of Alternaria rots.

When the incidence of Phomopsis stem-end rots was evaluatedafter the HWB treatment that followed the orchard treatmentswith water or with 0.1% or 1% NaOH, a reduction of about 85%was observed, irrespective of which orchard wash was used. How-ever, analysis of the effect of HWS on stem-end rot developmentrevealed reduced efficiency: the combination of any of the orchardtreatments – water, or 0.1 or 1% NaOH – with a subsequent HWStreatment reduced stem-end rot development to a level that washigher (but not always significantly so) by about 5–14% than that onfruit exposed to HWB; and in some experiments this difference wasenhanced during shelf-life at 20 ◦C, suggesting that HWS treatmentmight have limited capability to reduce stem-end rot developmentduring long periods of fruit storage.

3.5. Effects of HWB and HWS postharvest management on theincidence of black and red discoloration of lenticels in mango fruitcv. Shelly

The differences between the effects of the two managementpractices were confirmed by the following experiment, carried outunder fully commercial conditions. Harvested fruit, cv. Shelly werewashed in water at the orchard and then exposed to HWB or HWSmanagement under fully commercial conditions in the Shohampackinghouse. Fruit under each treatment were exposed to acidprochloraz sprays before they were stored for 25 days (Table 5).Incidence of lenticel discoloration, both red and black, was less

under HWS management than under HWB management: incidenceof red-lenticel symptoms was 33% less under HWS than under HWBtreatment, but was still higher than that in the fruit that were nottreated in the packinghouse. Incidence of black lenticels, usually

dence of Alternaria and stem-end rots on mango fruit cv. Keitt.

1% NaOH

ots (%) Stem end rots (%) Alternaria rots (%) Stem end rots (%)

51.1a 26.8a 16.4a6.1c 0.10b 5.4b20.0b 0.05b 10.0ab

1% NaOH

ots (%) Stem end rots (%) Alternaria rots (%) Stem end rots (%)

74.2a 18.9a 54.6a14.8b 15.3a 13.5c25.0b 0.10b 27.5b

-life). Average values within columns followed by unlike letters differ significantly

132 O. Feygenberg et al. / Postharvest Biology and Technology 91 (2014) 128–133

Table 5Effects of HWB and HWS packinghouse management on the incidence of lenticel discoloration and Alternaria side and Phomopsis stem-end rot of mango fruit cv. Shelly after25 days at 12 ◦C (end of storage). Each value represents the mean of six replicates, each of 15 fruit. Within columns average values followed by unlike letters differ significantlyat P < 0.05, according to the Tukey-Kramer HSD Test.

Packing-housetreatment

Red lenticels(index 0–3)

Black lenticels(index 0–3)

Alternaria side rots(% covered area)

Alternaria side rots(% unmarketable fruit)

Stem-end rots(% unmarketable fruit)

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Untreated 0.30c 1.11b 7.37aHWB 1.84a 1.72a 1.57bHWS 1.24b 1.33b 1.36b

aused by sap spreading, was 24% less under HWS than under HWBanagement, and did not differ from that in untreated fruit.Interestingly, the approximately 65% reduction of Alternaria rot

ncidence and the 80% reduction of the Alternaria-rot-covered areachieved through HWS treatment were similar to those achievedith the HWB treatment. However, incidence of Phomopsis-

nduced stem-end rots was reduced by 56% by the HWB but by only3% by the HWS treatment, suggesting that HWS was less efficienthan HWB for controlling stem-end rots.

. Discussion

The use of proper orchard and packinghouse management appli-ations, including treatments with safer fungicides (Kobiler et al.,001; Prusky et al., 2001) and appropriate physical treatmentsPrusky et al., 1999, 2001) during postharvest life are key factors inbtaining high-quality fruit. During the early stages of developmentf the Israeli mango industry, most efforts were focused on efficienteduction of decay blemishes and of fungicide residues, and theseere achieved through development of the short HWB treatment

ollowed by application of acidic prochloraz which reduced the inci-ence of postharvest diseases (Prusky et al., 1999, 2006). However,hese treatments have recently been shown to be associated withhe occurrence of a problem of lenticel discoloration that, proba-ly, was enhanced by the recent development of new cultivars thatave susceptible skins (Lavi et al., 1997).

The occurrence of postharvest discoloration of lenticels is aidespread problem in the mango industry; it was reported to

e influenced during harvesting or packing by a variety of factors.hese include: environmental conditions at harvest, such as lowemperatures and overcast or wet conditions (Bally et al., 1997;esis et al., 2000; Cronje, 2009a); fruit maturity (Simmons et al.,998; Jacobi et al., 2001); and postharvest procedures, such as hot-ater dipping (Jacobi et al., 2000; Self et al., 2006), treatment withetergents (Bally et al., 1997; O’Hare et al., 1999), and use of thelectrical conductivity of water baths (Cronje, 2009b).

Our analysis indicated that washing of the fruit, in the containersr bins, in water or in 0.1, 1 or 2% NaOH solution for 30 s imme-iately after harvest, significantly reduced lenticel discolorations,ll to similar levels. The effect of washing on black-lenticel dis-oloration probably resulted from prevention of sap burn of thekin, but the effect of washing in the orchard on the incidence ofed-lenticel discoloration indicates that the sap might also pro-ote development of red lenticels (Table 1). The effect of fruitashing on reduction of black-lenticel symptoms was further con-rmed by analysis of the effects of HWB at various intervals afteredicel detachment (Fig. 2): HWB carried out at immediately aftertem detachment reduced black-lenticel development almost fiveimes as effectively as its application 16 h after petiole detachmentFig. 2). Also, the effects of the combination of orchard washing withither water or NaOH, and packinghouse HWB treatment (Table 2)ndicated that brushing was an effective treatment for reducing

ncidence of black lenticels. This may indicate that reduction oflack-lenticel development can be achieved by washing the fruit,

n either the orchard or the packinghouse, during the early hoursfter harvest.

73.24a 42.89a24.66b 19.05b27.94b 29.13ab

However, one of the most significant effects of managementtreatments on fruit quality was that the stress induced by the HWBsignificantly enhanced red-lenticel development by about 5- to19-fold. These findings suggest that this type of discoloration isreduced by simple washing in the orchard (Table 1) but is enhancedby physical brushing of the fruit (water + brushing) (Fig. 2 andTable 2). Similar results that were obtained by Cronje (2009b) indi-cated that exposure of fruit to a number of brush sets and otherrollers in packinghouses might affect the incidence of red-lenticeldiscoloration. In light of the finding that HWB enhanced red-lenticeldiscoloration up to 19-fold (Table 2), and of previous results whichalso indicated that wax brushing did not affect the incidence ofred lenticels (Cronje, 2009a,b), a packinghouse management com-prising HWS treatment without brushing was developed. For thispurpose the hot water was applied over simple rollers on which thefruit were exposed to hot water sprayed from nozzles for 10–15 s(Fig. 1), and lenticel discoloration was reduced by more than 50%(Table 3).

Hot water brushing was implemented in Israel as a treatmentthat controlled disease by removing spores from the fruit peelduring early stages of fungal colonization. Prusky et al. (1999) sug-gested that hot water application and brushing contributed jointlyto the removal of spores from the fruit skin and thereby reducedAlternaria and stem-end rots (Prusky et al., 2006). Comparison ofHWB and HWS treatments indicated that HWS treatment was moreeffective for controlling Alternaria side rots after 35 days of stor-age of cv. Keitt fruit at 12 ◦C (Table 4). However, following 5 daysat 20 ◦C the incidence of Alternaria side rots in HWS-treated fruitsignificantly increased and did not always differ from that in HWB-treated ones. These results suggest that no brushing is needed forcontrol of Alternaria side rots. However, when efficiencies of pack-inghouse treatments in controlling stem-end rots were compared,HSW treatment was found to be about 35% less effective than HWBtreatment. The lower efficiency of HWS in controlling stem-endrots was also observed after shelf-life, suggesting that the combi-nation of hot water and brushing in the HWB treatment probablyremoved more residual spores from the stem region than the hotwater spray alone.

Comparison between the effects of the HWB and HWS treat-ments on the incidence of lenticel discoloration showed that HWSwas able to reduce the incidence of red discoloration by 50–70%and that of black discoloration by 50–60%, which suggests thatthe HWS was sufficiently effective to reduce black lenticel devel-opment, while being gentle enough to prevent stress-induced reddiscoloration. Similar results were obtained in experiments carriedout in other years and in other packinghouses (Tables 3–5): discol-oration was always reduced by at least 50% (results not shown).Because in Israel the HWS treatment is applied in combinationwith an acid prochloraz treatment (50 mM HCl with prochloraz at125 �g mL−1) it still could be that the acid treatment at pH 2–3 fur-ther contributed to reduction of lenticel discoloration; however,this possibility might be discarded in light of Cronje’s (2009b) find-

ing that exposure of ‘Tommy Atkins’ mango fruit to pH 3.0 resultedin less black lenticel development than exposure to pH 5.0, whichsuggests that low pH may contribute to the prevention of thistype of symptom. Interestingly, red lenticel discoloration of fruit

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ot exposed to any packinghouse treatment increased 4-fold fol-owing HWS treatment (Table 5), which suggests that still otheractors in the packinghouse (rollers, impacts, etc.) contribute to theevelopment of red discoloration of lenticels.

The findings that cultivars such as ‘Shelly’, ‘Tommy Atkins’nd ‘Keitt’ were strongly susceptible to lenticel discolorationOosthuyse, 1998; Bezuidenhout et al., 2005; Cronje, 2009a; Dulooy et al., 2006) indicate that mango fruit management, both inhe orchard and in the packinghouse, must be continually assessed.he present results indicate that water washing in the orchardnd subsequent HWS treatment contribute to enhancing mangoruit quality by reducing the severity of lenticel discoloration andlternaria rot. However, exposure of mango fruits to HWS instead ofWB was not sufficient to reduce the incidence of stem-end decay,nd the addition of postharvest fungicide(s) treatment(s) will beequired to solve these new problems. It is suggested that man-gement conditions should be tested and optimized locally in eachountry/region, according to the various parameters that affect fruituality and in light of the anticipated storage period.

cknowledgments

We thank S. Shery (Tzemach Avocado Packing House) and M.hoham (Shoham Packing House) for permitting us to performxperiments in their packinghouses. We also thank Dr. Yoram Fuchsor reviewing the manuscript, and the Israel Mango Growers’ Asso-iation for partial financial support.

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