Ho

Ma

b

a

ARRA

KSASA

1

csvfrTriipaatatMpt

BT

0d

Scientia Horticulturae 125 (2010) 239–247

Contents lists available at ScienceDirect

Scientia Horticulturae

journa l homepage: www.e lsev ier .com/ locate /sc ihor t i

exanal and 1-MCP treatments for enhancing the shelf life and qualityf sweet cherry (Prunus avium L.)

ohini Sharmaa, Jissy K. Jacoba, Jayasankar Subramanianb, Gopinadhan Paliyatha,∗

Department of Plant Agriculture, University of Guelph, Guelph, Ontario N1G 2W1, CanadaDepartment of Plant Agriculture, University of Guelph, Vineland Station, 4890 Victoria Avenue North, Vineland, Ontario L0R 2E0, Canada

r t i c l e i n f o

rticle history:eceived 16 June 2009eceived in revised form 21 January 2010ccepted 31 March 2010

a b s t r a c t

Sweet cherry has a short post-harvest shelf life and this greatly affects the consumer preference and exportof fresh fruits. In this study, the effects of pre-harvest application of a hexanal formulation (enhancedfreshness formulation, EFF) and post-harvest application of hexanal vapour and 1-MCP on quality param-eters and shelf life of sweet cherry were investigated. Cherries subjected to pre-harvest spray with EFF

◦

eywords:weet cherrynthocyaninuperoxide dismutasescorbate peroxidase

had better color, brightness and firmness than unsprayed cherries even after 30 days of storage at 4 C.These EFF-treated cherries also showed higher chroma values indicative of enhanced red color. Post-harvest application of either, hexanal vapour, 1-MCP, or a combination of both, enhanced the firmness ofcherries. These treatments also resulted in higher levels of superoxide dismutase and ascorbate peroxi-dase activities. The levels of anthocyanins and phenolic components were either enhanced or maintainedduring the 30-day storage period. Our results suggest that a pre-harvest application of EFF combined with

f hex

post-harvest treatment o

. Introduction

Numerous evidences support the contention that nutraceuti-al components such as anthocyanins in fruits reduce the risk ofeveral chronic degenerative diseases such as cancer and cardio-ascular diseases (Kang et al., 2003; Scalbert et al., 2005). However,ruits undergo several changes after harvest, which in most cases,esult in a decrease in nutritional compounds (Macheix et al., 1990).herefore, maintaining the levels of components with health-egulatory properties after harvest and during post-harvest storages an objective of great interest. Sweet cherry, Prunus avium L.,s a table fruit with a high market demand due to its seasonalroduction and presence of health-promoting compounds suchs anthocyanins and other phenolics. One of the major problemsssociated with transportation and marketing of sweet cherries isheir short post-harvest shelf life. In non-climacteric fruits suchs sweet cherry and grapes, ethylene does not significantly affect

he quality and post-harvest shelf life (Palou et al., 2003). 1-

ethylcyclopropene (1-MCP) blocks the ethylene receptors, andrevents binding of ethylene to its receptors, thus regulating theissue response to ethylene. The application of 1-MCP in climac-

∗ Corresponding author at: Department of Plant Agriculture, Edmond C. Boveyuilding, University of Guelph, Guelph, Ontario N1G 2W1, Canada.el.: +1 519 824 4120x54856; fax: +1 519 767 0755.

E-mail address: gpaliyat@uoguelph.ca (G. Paliyath).

304-4238/$ – see front matter © 2010 Elsevier B.V. All rights reserved.oi:10.1016/j.scienta.2010.03.020

anal and 1-MCP may enhance the quality and shelf life of sweet cherry.© 2010 Elsevier B.V. All rights reserved.

teric fruits, such as apple, plum, banana and pear has been shownto delay the ripening and senescence of fruits (Blankenship andDole, 2003). 1-MCP treatment in some non-climacteric fruits suchas strawberry, extended the post-harvest life of treated fruits,although at a higher concentration it reduced the fruit quality (Ku etal., 1999). The effects of 1-MCP vary with several application param-eters including concentration, time and temperature, as well as thenature of commodity (De Ell et al., 2001; Gong et al., 2002). In pre-vious studies, no significant effects from 1-MCP and ethylene werenoticed on the color and firmness of sweet cherries (Gong et al.,2002; Mozetic et al., 2006). Despite being non-climacteric, sweetcherry fruits undergo similar biochemical changes as in climac-teric fruits that bring about the ideal quality characteristics such assweetness, softness (cell wall softening), reduction in acidity andan increase in polyphenols and anthocyanins. Therefore, it is prob-able that 1-MCP may exert beneficial effects on the shelf life andquality of sweet cherry.

The process of membrane degradation initiated by the actionof phospholipase D (PLD) during ripening and senescence is alsoenhanced by reactive oxygen species (ROS) produced during enzy-matic processes and stress conditions (Paliyath and Droillard,1992). Hexanal, a naturally occurring volatile C6 aldehyde has been

observed to be a strong inhibitor of PLD action, and technologies forits application for enhancing shelf life and quality of fruits, vegeta-bles and flowers are currently under development (Paliyath et al.,1999, 2003; Paliyath and Murr, 2007; Paliyath and Subramanian,2008). It was hypothesized that by deliberate inhibition of catabolic

2 orticu

ramatftti

2

2

wSfd

2

2

has(astgtuou

falra

semut

2

httpthATywitcaa

40 M. Sharma et al. / Scientia H

eactions (stimulated by ethylene and PLD) using 1-MCP and hex-nal, metabolites can be channeled to beneficial pathways, whichay eventually enhance sensory and nutritional qualities, as well

s shelf life of cherry fruits (Sharma et al., 2008). Thus, the objec-ives of this study were to evaluate changes in qualities in cherryruits by inhibiting ethylene and phospholipase D action throughhe pre-harvest application of an ‘enhanced freshness formula-ion’ containing hexanal (EFF), or by using post-harvest treatmentsnvolving 1-MCP and hexanal.

. Materials and methods

.1. Fruit material and source

Sweet cherry (Bing) fruits were usually harvested in the firsteek of July at commercial maturity from the Vineland Research

tation, University of Guelph, Ontario, Canada. After harvesting, theruits were stored at 4 ◦C. Fruits sorted for uniform maturity andevoid of wounds or rots were selected for the study.

.2. Treatments

.2.1. Pre-harvest treatmentsSweet cherry trees were sprayed twice (15 and 7 days before

arvest) with the enhanced freshness formulation (EFF) (Paliyathnd Murr, 2007; Paliyath and Subramanian, 2008) during the 2005eason. The basic ingredients of the stock formulation include 1%v/v) hexanal, 1% (v/v) geraniol, 1% (w/v) �-tocopherol, 1% (w/v)scorbic acid, 0.1% (w/v) cinnamic acid, 0.1% (v/v) Tween 80 dis-olved in ethanol (10% v/v). The stock solution was mixed in watero provide 1% (1–100 l final) or 2% (1–50 l final) along with orchardrade calcium chloride (1%, w/v) and sprayed at a rate of 10 l perree using a pressurized nozzle sprayer directed to the canopy fromnderneath the trees. Nine trees located in different locations of therchard were selected randomly for the study, and three trees weresed for each treatment.

In 2007 season, the trees were sprayed with components of theormulation to identify their potential effects in enhancing shelf lifend quality. In addition to the original EFF, two additional formu-ations, one containing hexanal alone and another containing theest of the components were used. The formulations were sprayedt a concentration of 2% (v/v).

In previous studies, the fruits from control trees that wereprayed with water containing the same amount of detergent,thanol and 1% (w/v) calcium chloride as used in EFF treat-ent, showed similar quality characteristics to the fruits from

nsprayed trees. Therefore, in the present studies, the fruits fromhe unsprayed trees were used as controls for analysis.

.2.2. Post-harvest treatmentsDifferent post-harvest treatments were performed 24 h after

arvest on cherries stored at 4 ◦C. There were three replicates (fromhree different trees) for each treatment, and each replicate hadhree boxes each containing 1 kg cherries and were placed in 6 millastic bags after post-harvest treatment. Control and pre-harvestreated (1 and 2% EFF) sweet cherries were treated with 0.01% (w/w)exanal (Paliyath et al., 2003) and 1 ppm 1-MCP (SmartFreshTM,groFresh, a Rohm and Haas Company), alone and in combination.o generate 1-MCP, a known weight of SmartFreshTM powder, toield 1 ppm within the bag volume, was mixed in 20 ml distilledater in a beaker. The required amount of hexanal was measured

nto a beaker and kept in contact with a strip of Whatman 3 fil-er paper to enable fast evaporation. The bags were immediatelylosed and sealed prior to the release of hexanal, 1-MCP and hex-nal with 1-MCP. Post-harvest treatments were performed at 4 ◦Cnd 90–95% relative humidity for 24 h. Identical sets of untreated

lturae 125 (2010) 239–247

control and pre-harvest EFF-treated cherries for the specific post-harvest treatment were sealed in 6 mil plastic bags and exposed toair. After 24 h of treatment, sweet cherries were removed from thebags and placed in cold storage at 4 ◦C and 90–95% relative humidityuntil further use for analysis of fruit quality.

2.3. Standard quality assessment

2.3.1. ColorColor of the fruits was measured by Minolta chromameter

(Model CR-300). For the color measurement, 25 fruits were ran-domly picked from each tree replicate and color was expressedaccording to the CIE Lab system (L – brightness, a – red/green and b– yellow/blue). The skin color was measured 2, 15 and 30 days afterharvest in all treated and untreated fruits. The L, a, b values wereconverted to L, C, H◦ [(lightness indicative of brightness), Chroma,a measure of color clarity (a2 + b2)1/2, and Hue angle (tan−1 (b/a))]using a software available at http://www.easyrgb.com.

2.3.2. FirmnessFruit firmness was measured as penetration force on the fruit

flesh and the results are expressed in Newton/cm. A penetrom-eter (Effegi pressure tester, Facchini 48011, Alfonsine, Italy) witha 7 mm tip was used to measure the firmness. The tip was pushedinto the cherry through an automatic lever device to obtain uniformapplication of force and firmness was measured from 25 fruits rep-resentative of each replicate used for the color measurement. Thekg-force observed was converted to Newton/cm by multiplying afactor of 0.098 (1 N/m/s2 = 1 kgf).

2.3.3. Soluble solidsA handheld prism refractometer (Fisher Scientific, Mississauga,

Canada with a measurement range of 0–25◦Brix) was used for themeasurement of soluble solids, and results were expressed as %soluble solids. To measure soluble solids, cherry juice extractedfrom 25 fruits that were used for the firmness measurement wascollected in a Petri dish.

2.4. Extraction and identification of polyphenolic componentsfrom sweet cherry

2.4.1. Extraction of polyphenolsTen grams of sweet cherries were homogenized in 10 ml of

100% methanol for 2.5 min using a Brinkmann homogenizer (Poly-tron PTA 10). The homogenate was centrifuged (Beckman J2-21) at15,000 rpm for 15 min at 4 ◦C. The supernatant was collected anddried in a speedvac concentrator (Savant, Speedvac SVC 200). Theresulting pellet was dissolved in 10 ml of distilled water. The sam-ples were passed through separate C18 Sep-Pak cartridges (Waters,Milford, MA, USA), and total phenolics were eluted with 1 ml of100% methanol. Samples were divided into 1 ml aliquots and keptat −40 ◦C until further use.

2.4.2. Estimation of total phenolicsTo estimate the total phenolic content in sweet cherry, the Folin-

Ciocalteau method was used (Jacob et al., 2008). Sample and 50%ethanol (1:1, v/v) were mixed in 5 ml distilled water along with0.5 ml of Folin-Ciocalteau’s phenol reagent (2N stock, Sigma Chem-ical Company, St. Louis, USA). Samples were mixed thoroughly andincubated for 5 min in the dark. After 5 min, 5% (w/v) sodium car-

bonate (Na2CO3) was added to the solution, stirred, and incubatedfor 1 h in the dark. Subsequently, the absorbance was measured at725 nm by a UV spectrophotometer (Milton Roy Spectronic 1001plus). For each sample, measurements were done in triplicates. Astandard curve was generated using gallic acid with concentrations

orticu

rm

2c

iadsiNaSCiws0Bp4m

2

2

pdadah(wSe4bstaambrp

2

saer

2acmtwcost

M. Sharma et al. / Scientia H

anging from 25 to 300 �g/ml. Total phenolics were expressed asilligrams gallic acid equivalent per gram fresh weight.

.4.3. Separation and identification of anthocyanin and phenolicomponents

An Agilent 1100 series HPLC–MS was used for the separation anddentification of phenolic and anthocyanin components (Jacob etl., 2008). The elution profile was monitored by a photodiode arrayetector coupled with sprayer, and ions were generated by atmo-pheric pressure chemical ionization (APCI) and electron sprayonization (ESI) in both negative and positive ionization modes.itrogen gas was used as nebulizing and drying gas. The phenolicsnd anthocyanins were detected at 260 and 520 nm, respectively.weet cherry extracts were analyzed by an XterraTM reverse phase18 column (column size – 3.9 × 150 mm; Particle size – 5 �m). The

njection volume for the samples was 50 �l. The mobile phasesere: solvent A (HPLC grade acetonitrile–0.2% formic acid) and

olvent B (HPLC grade water–0.2% formic acid). The gradient was:–5 min, 95% B; 5–30 min, 70% B; 30–45 min, 0% B; 45–65 min, 95%with a flow rate of 0.2 ml/min. The ESI conditions were: nitrogenressure, 60 psig; drying gas, 12 l/min at 350 ◦C; ion spray voltage,000 V; and fragmentor voltage, 80 V. For each sample, measure-ents were done in triplicate.

.5. Extraction and analysis of antioxidant enzyme activity

.5.1. Protein extractionFruit tissues (5 gm) were homogenized in 5 ml sodium

hosphate buffer (100 mM; pH 7.5) containing 1 mM ethylene-iaminetetraacetate (EDTA), 1% polyvinylpyrrolidone (PVP-40)nd 1 mM phenylmethylsulfonylfluoride (PMSF) dissolved in 1 mlimethyl sulfoxide (DMSO). Homogenization was done with

Brinkmann homogenizer (Polytron PTA 10) for 2 min. Theomogenate was filtered through cheesecloth and centrifugedBeckman J2-21) at 12,000 rpm for 20 min at 4 ◦C. The supernatantas collected, and 2.5 ml of the extract was passed through a

ephadex G-25 column (PD-10 Pharmacia). The columns were pre-quilibrated with 100 mM sodium phosphate buffer (pH 7.5) at◦C. The proteins were eluted with 100 mM sodium phosphateuffer (pH 7.5) at 4 ◦C, and protein samples were immediatelytored at −80 ◦C until further analyses. All steps in protein extrac-ion for determining APX activity were performed as describedbove, except that the homogenization buffer also contained 5 mMscorbate. Protein concentration was determined by the Bradfordethod (Bradford, 1976). A standard curve was generated using

ovine serum albumin (BSA) as a standard with concentrationsanging from 0.8 to 10 �g/ml. Protein is expressed as �g proteiner gram fresh weight.

.5.2. Analysis of antioxidant enzyme activityAll enzyme assays were run using a Spectronic 1001 plus UV

pectrophotometer at the indicated wavelengths. Total and specificctivities of superoxide dismutase and ascorbate peroxidase arexpressed as nmol/min/g fresh weight and nmol/min/�g protein,espectively.

.5.2.1. Superoxide dismutase (SOD). SOD activity was determineds described by Madamanchi et al. (1994). The assay mixtureontained 50 mM potassium phosphate buffer (pH 7.8), 13 mMethionine, 0.1 mM EDTA, 75 �M NBT, and 1 �g protein in a reac-

ion volume of 1 ml. Riboflavin (2 �M) was added and the reaction

as initiated by illuminating the tubes under a 15 W fluores-

ent lamp. The reaction was terminated after 15 min by turningff the fluorescent lamp. Samples covered with aluminum foilerved as non-illuminated blanks. The ability of SOD to inhibithe photochemical reduction of nitroblue tetrazolium (NBT) (molar

lturae 125 (2010) 239–247 241

extinction coefficient, 15 mM−1 cm−1) was measured at 560 nm.The amount of reduced NBT was calculated using its molar extinc-tion coefficient.

2.5.2.2. Ascorbate peroxidase (APX). APX activity was determinedby the ascorbate (molar extinction coefficient, 2.8 mM−1 cm−1)dependent decomposition of H2O2 as described by Rao et al.(1996). The decomposition of H2O2 was measured by followingthe decrease in A290 for 5 min. The 1 ml reaction volume contained100 mM potassium phosphate buffer (pH 7.5), 0.5 mM ascorbateand 1 mM H2O2. The reaction was initiated by adding 10 �g protein.

2.6. Statistical analysis

The experimental design involved the use of three individualtree replicates randomly located in the orchard for each main treat-ment viz. the untreated control, EFF 1% and EFF 2% spray treatments,respectively. Fruits were collected separately from each tree andindividual samples from each tree were subjected to no treatment(air), hexanal vapour treatment, MCP treatment and a combina-tion of hexanal and MCP. These fruits were further subjected toquality analysis during storage for 15 and 30 days. Altogether,the treatments included three main treatments followed by foursub treatments and three time periods of analysis (2 days for themain treatment, 15 and 30 days for all treatment) thus followinga split–split plot design. Statistical analysis was performed usingGraphPad Prism version 4.0 software. For each experiment, themean of three replicates from each treatment (75 in total) wascalculated by column statistics and standard error was calculated.To determine the difference between control and treated cherries,one-way ANOVA was used. Tukey’s test was used to determine sig-nificantly different means of the treatments between control andtreated cherries at p < 0.05.

3. Results

3.1. Effect of treatments on fruit color

Changes in color intensity and quality are important indica-tors of maturity and quality for fresh cherries. The developmentof red color is an index of maturity and a shift from a deep redcolor to a purple color occurs during the advancement of ripen-ing that can be used to predict the grades in sweet cherries. Thebrightness, red intensity, and the yellow intensity were measuredusing a Minolta chromameter (L, a, b) and these values were used tocalculate the chromaticity parameters lightness (L), chroma (C, anindicator of redness) and hue angle [H◦, a relative ratio of the yellowintensity to red intensity expressed as tan−1 (b/a)]. Under condi-tions where both red intensity and yellow intensity change, thechanges in hue angle will be a more reliable parameter to expressthe increase in red intensity relative to yellow intensity, a decreas-ing hue angle indicating a progressively increasing red intensity,a 90◦ hue angle indicating pure yellow and 0◦ angle indicatingpure red. Cherries sprayed with 2% EFF showed a higher L value,35% higher (p < 0.05) chroma intensity (C) value, and a marginallyhigher hue angle than those sprayed with 1% EFF and untreatedcontrol fruits indicating slower senescence (Table 1). The chromaand hue angle values of fruits from all treatments declined duringstorage for 15 and 30 days. The chroma values (C) from 2% EFF-

treated fruits were maintained at a slightly higher (p < 0.05) levelduring post-harvest storage. Post-harvest treatments with hexanal,1-MCP or a combination of both, did not result in any major changesin the chromaticity parameters during storage (data not shown) bycomparison to the respective control fruits.

242 M. Sharma et al. / Scientia Horticulturae 125 (2010) 239–247

Table 1Chromaticity parameters of sweet cherries subjected to pre- and post-harvest treat-ments. Sweet cherries were stored for 2, 15 and 30 days in air at 4 ◦C and 90–95%relative humidity.

Treatments Chromaticity parameters

Pre-harvest Post-harvest L C H◦

Control Air (2 day) 31.50 21.35 15.211% EFF Air (2 day) 31.30 21.90 14.542% EFF Air (2 day) 34.11 29.47 18.80Control Air (15 day) 30.30 16.57 12.191% EFF Air (15 day) 29.91 15.51 11.522% EFF Air (15 day) 30.62 18.60 13.36Control Air (30 day) 28.61 10.75 9.641% EFF Air (30 day) 27.80 11.71 10.832% EFF Air (30 day) 29.00 12.71 10.42

Data are the mean of chromaticity parameters calculated from three replicates,each containing 25 fruits. The chromaticity parameters lightness L, chroma C andhh

3

sscfidhwaraMawtes

TFSh

DShstata

Table 3Total phenolics (mg gallic acid equivalent/g fresh weight) in sweet cherries subjectedto pre- and post-harvest treatments. Sweet cherries were stored for 2, 15 and 30 daysin air at 4 ◦C and 90–95% relative humidity.

Treatments Phenolics Levels (mg gallic acid equivalent)

Pre-harvest Post-harvest 2 Days 15 Days 30 Days

Control Air 0.8 ± 0.2 1.1 ± 0.1 0.8 ± 0.11% EFF Air 0.7 ± 0.1 0.9 ± 0.1 1.0 ± 0.22% EFF Air 0.6 ± 0.1 A1.2 ± 0.1 0.9 ± 0.1

ue angle H◦ were calculated from CIE L, a, b values by a procedure available atttp://www.easyrgb.com.

.2. Effect of treatments on fruit firmness

Firmness increased slightly in EFF- sprayed and unsprayedweet cherries during storage. Cherries sprayed with 2% EFFhowed marginally higher firmness after 30 days of storage asompared to the control and 1% EFF sprayed fruits (Table 2). Thermness of 2% EFF sprayed fruits increased slightly from 0.46 N onay 2 after harvest to 0.50 N on day 15 and to 0. 52 N on day 30 afterarvest, an overall 13% increase (Table 2). Post-harvest treatmentith hexanal significantly enhanced (p < 0.05) the fruit firmness

fter 15 days of storage. Control and 1% EFF sprayed sweet cher-ies showed an 18% increase in firmness (0.47–0.58 N in controlnd 0.49–0.58 N in 1% EFF) after exposure to 0.01% (w/w) hexanal.CP treatment enhanced the firmness in control, 1% EFF sprayed

nd 2% EFF sprayed fruits by 15–25% (p < 0.05). Maximum effects

ere observed on 15 days after harvest, and the firmness was bet-

er maintained in fruits subjected to 2% EFF treatment and furtherxposed to 1-MCP (Table 2). The increase in firmness was veryimilar when exposed to hexanal and 1-MCP together; however,

able 2irmness (N/cm) of sweet cherries subjected to pre- and post-harvest treatments.weet cherries were stored for 2, 15 and 30 days in air at 4 ◦C and 90–95% relativeumidity.

Treatments Firmness (N/cm)

Pre-harvest Post-harvest 2 Days 15 Days 30 Days

Control Air 0.47 ± 0.01 0.49 ± 0.01 0.50 ± 0.011% EFF Air 0.49 ± 0.01 0.49 ± 0.01 0.50 ± 0.012% EFF Air 0.46 ± 0.01 0.50 ± 0.01 A0.52 ± 0.01

Control Hexanal A0.58 ± 0.01c A0.53 ± 0.011% EFF Hexanal A0.58 ± 0.01c 0.52 ± 0.012% EFF Hexanal A0.53 ± 0.01 A0.52 ± 0.01

Control MCP A0.57 ± 0.01c 0.47 ± 0.011% EFF MCP A0.57 ± 0.01c 0.51 ± 0.012% EFF MCP A0.58 ± 0.02c A0.54 ± 0.01b

Control Hexanal + MCP A0.54 ± 0.01 0.50 ± 0.011% EFF Hexanal + MCP 0.54 ± 0.01 0.54 ± 0.012% EFF Hexanal + MCP A0.56 ± 0.01c 0.51 ± 0.01

ata are the mean ± standard error of three replicates, each containing 25 fruits.tatistically significant (p < 0.05) values are designated by different letters. Meansaving the superscript A are significantly different from the respective treatmentets on day 2. Means within columns followed by different superscripts [withinreatments; a – pre-harvest/air treatments, b – within post-harvest treatments (hex-nal, MCP and combination – 15 and 30 days) and c – between pre-harvest/airreatment values for 15-day, 30-day and the respective post-harvest treatments]re significantly different.

Data are the mean ± standard error of three replicates. Statistically significant(p < 0.05) values are designated by different letters. Means having the superscript Aare significantly different from the respective treatment sets on day 2.

firmness was maintained better during post-harvest storage (from15 to 30 days).

There were no major differences in the soluble solids contentbetween control cherries and those that were sprayed with the EFF,at harvest or after post-harvest treatments, during extended stor-age (data not shown). In general, the soluble solids content variedbetween 15 and 16% Brix.

3.2.1. Total phenolics contentThe levels of total phenolic components in pre- and post-harvest

treated sweet cherries are given in Table 3. The phenolic contentof control and 2% EFF sprayed sweet cherries were 0.8 mg/g freshweight and 0.6 mg/g fresh weight, respectively, on day 2 after har-vest. A slight increase in phenolics to 1.1 mg/g fresh weight and1.2 mg/g fresh weight, respectively, was noticed on day 15 after har-vest. The phenolics level remained at similar levels during furtherstorage. Post-harvest exposure with hexanal, 1-MCP or both didnot have any major effects on the content of phenolic components(data not shown).

3.2.2. Quantification of phenolics and anthocyanins by HPLC–MSTo identify and quantify the phenolic and anthocyanin com-

ponents in the pre- and post-harvest treated sweet cherries, fruitextracts were analyzed using HPLC–ESI-MS. Since the phenolic con-tent of 1% EFF sprayed sweet cherries was lower than the controlin most of the treated and untreated sweet cherries (Table 3),HPLC–ESI-MS analysis was performed only for the control and 2%

EFF sprayed sweet cherries with and without exposure to post-harvest treatments.

The phenolic contents of control fruits and fruits subjectedto pre- and post-harvest treatments are shown in Table 4. Themajor phenolic components in sweet cherries were neochloro-

Table 4Levels of phenolic acids (�mol/mg phenols) in sweet cherries subjected to pre-harvest treatment with EFF. Sweet cherries were stored for 2, 15 and 30 days inair at 4 ◦C and 90–95% relative humidity.

Treatments Day of Analysis

Pre-harvest Post-harvest 2 Days 15 Days 30 Days

Neochlorogenic acidControl Air 0.19 ± 0.03 0.11 ± 0.02 0.10 ± 0.022% EFF Air 0.17 ± 0.02 A0.30 ± 0.02a 0.17 ± 0.02a

p-Coumaroyl-quinic acidControl Air 0.14 ± 0.01 0.20 ± 0.02 0.10 ± 0.002% EFF Air 0.29 ± 0.01a A0.14 ± 0.01a A0.15 ± 0.02

Feruloyl glucoseControl Air 0.24 ± 0.01 A0.13 ± 0.02 A0.15 ± 0.022% EFF Air 0.18 ± 0.01a 0.23 ± 0.01a 0.18 ± 0.00

Data are the mean ± standard error of three replicates. Statistically significant(p < 0.05) values are designated by different letters. Means having the superscript Aare significantly different from the respective treatment sets on day 2. Means withincolumns followed by a small letter superscript are significantly different (p < 0.05)from the respective control value.

M. Sharma et al. / Scientia Horticulturae 125 (2010) 239–247 243

Table 5Levels of cyanidin-3-rutinoside (�mol/mg phenols) in sweet cherries subjected to pre- harvest treatment with EFF. Sweet cherries were stored for 2, 15 and 30 days in air at4 ◦C and 90–95% relative humidity.

Treatments Cyanidin-3-rutinoside

Pre-harvest Post-harvest 2 Days 15 Days 30 Days

.37 ± 0.03 1.38 ± 0.03 1.29 ± 0.04

.50 ± 0.17 1.48 ± 0.02a 1.25 ± 0.02

D ed by a superscript are significantly different (p < 0.05) from the respective control value.

goEicw0u0t

cdllop(w

spicTodac

3c

3

Isradaciaf

33SoSrhEPb

Table 6Protein concentration (�g protein/g fresh weight) in sweet cherries subjected topre- and post-harvest treatments. Sweet cherries were stored for 2, 15 and 30 daysin air at 4 ◦C and 90–95% relative humidity.

Treatments Protein levels (�g protein/g fresh weight)

Pre-harvest Post-harvest 2 Days 15 Days 30 Days

Control Air 59.8 ± 7.3 A93.2 ± 6.9 A104.3 ± 12.81% EFF Air 79.1 ± 16.0 113.1 ± 8.8 109.4 ± 8.22% EFF Air 74.2 ± 11.8 A129.0 ± 8.8 99.3 ± 13.7

Control Hexanal A86.4 ± 6.8 A94.5 ± 3.81% EFF Hexanal 80.6 ± 8.2c 89.8 ± 10.32% EFF Hexanal 76.3 ± 8.0c 85.4 ± 5.0

Control MCP A101.6 ± 11 A96.9 ± 11.41% EFF MCP 94.5 ± 6.5 90.5 ± 7.62% EFF MCP 88.1 ± 5.1c 98.6 ± 5.3

Control Hexanal + MCP A95.5 ± 0.9 A111.1 ± 8.21% EFF Hexanal + MCP 92.5 ± 6.3 105.7 ± 1.52% EFF Hexanal + MCP 87.6 ± 0.9c 102.6 ± 3.0

Data are the mean ± standard error of three replicates. Statistically significant(p < 0.05) values are designated by different letters. Means having the superscript Aare significantly different from the respective treatment sets on day 2. Means within

the untreated controls by nearly 288% after 15 days of storage. Dur-ing storage for another 15 days, SOD activity slightly declined inthese cherries (day 30), however, the levels were almost 4-foldhigher as compared to the air exposed control fruits. MCP treatment

Table 7Specific activity of superoxide dismutase (nmol NBT reduced/�g protein) in sweetcherries subjected to pre- and post-harvest treatments. Sweet cherries were storedfor 2, 15 and 30 days in air at 4 ◦C and 90–95% relative humidity.

Treatments Superoxide dismutase activity

Pre-harvest Post-harvest 2 Days 15 Days 30 Days

Control Air 18.4 ± 0.2 A8.1 ± 0.2 A6.2 ± 0.11% EFF Air 17.1 ± 0.2 A7.7 ± 0.2 A6.2 ± 0.52% EFF Air 13.3 ± 1.3a A7.5 ± 0.3 A6.4 ± 0.3

Control Hexanal A31.4 ± 0.5c A23.0 ± 0.2c

1% EFF Hexanal A30.2 ± 0.7c A21.8 ± 0.8c

2% EFF Hexanal A30.3 ± 0.4c A21.2 ± 0.4c

Control MCP A13.5 ± 0.3c A33.4 ± 0.3c

1% EFF MCP A12.4 ± 0.3c A31.0 ± 1.5c

2% EFF MCP 11.6 ± 0.8c A31.2 ± 0.5c

Control Hexanal + MCP A5.43 ± 0.3c A54.3 ± 0.8c

1% EFF Hexanal + MCP A4.14 ± 0.2c A52.7 ± 1.9c

2% EFF Hexanal + MCP A4.80 ± 0.4c A50.9 ± 0.4c

Data are the mean ± standard error of three replicates. Statistically significant

Control Air 12% EFF Air 1

ata are the mean ± standard error of three replicates. Means within columns follow

enic acid, p-coumarylquinic acid and feruloylglucose. The levelsf neochlorogenic acid were almost similar in control and 2%FF-treated sweet cherries 2 days after harvest (Table 4). Dur-ng storage, the levels of neochlorogenic acid in control sweetherries had decreased to 0.11 �mol/mg phenols (42% reduction),hile in 2% EFF-treated sweet cherries the levels increased to

.30 �mol/mg phenols (76% increase) (p < 0.05). During contin-ed storage, neochlorogenic acid levels decreased from 0.30 to.17 �mol/mg phenols in 2% EFF-treated fruits, but was still higherhan that in the control fruits.

The amounts of p-coumaroylquinic acid in 2% EFF sprayed sweetherries were significantly higher than control fruits initially, buteclined by 48% during subsequent storage (Table 4). The initial

evels of feruloylglucose in 2% EFF-treated fruits were significantlyower than the control fruits on day 2 after harvest. The levelsf feruloylglucose in control fruits decreased (0.24–0.15 �mol/mghenols) during storage, showing a 38% decrease by day 30Table 4). Overall, the levels of all of these phenolic componentsere higher in 2% EFF sprayed sweet cherries during storage.

Cyanidin-3-rutinoside was the major anthocyanin inweet cherries. Cyanidin-3-glucoside, peonidin-3-rutinoside,elargonidin-3-rutinoside and petunidin-3, 5-diglucoside were

dentified as minor anthocyanins. The changes in the levels ofyanidin-3-rutinoside during storage of cherries are shown inable 5. Pre-harvest EFF spray marginally increased the levelsf cynidin-3-rutinoside. The levels remained nearly the sameuring post-harvest storage. Post-harvest treatments with hex-nal, 1-MCP or both together did not show any increase inyanidin-3-rutinoside levels in sweet cherries (data not shown).

.3. Protein content and antioxidant enzyme activities in sweetherry

.3.1. Protein levelsJust as in other fruits, protein levels were low in sweet cherry.

n general, protein levels increased from their initial levels duringtorage (Table 6). The protein levels in 2% EFF sprayed sweet cher-ies increased significantly from 74.2 �g/g fresh weight on day 2fter harvest to 129.0 �g/g fresh weight on day 15, but thereaftereclined to 99.3 �g/g fresh weight on day 30 after harvest. Overall,34% increase in protein levels was found in 2% EFF sprayed sweetherries. A similar increase (38%) in protein levels was also notedn 1% EFF-treated fruits. In general, post-harvest treatments of hex-nal, 1-MCP, and hexanal plus 1-MCP did not significantly increaseruit protein levels.

.3.2. Antioxidant enzymes activities

.3.2.1. Changes in superoxide dismutase (SOD) activity. The levels ofOD activity were highly variable in cherry fruits subjected to vari-us post-harvest treatments. In general, EFF treatment reduced theOD activity. A 27% reduction in SOD activity was observed in cher-

ies subjected to 2% EFF treatment during initial analysis 2 days afterarvest. The SOD activity declined in control, 1% EFF sprayed and 2%FF sprayed cherries during further post-harvest storage (Table 7).ost-harvest hexanal and 1-MCP treatment either alone or togetherrought about dramatic increase in SOD activity. Post-harvest hex-

columns followed by different superscripts [within treatments; a – pre-harvest/airtreatments, b – within post-harvest treatments (hexanal, MCP and combination – 15and 30 days) and c – between pre-harvest/air treatment values for 15-day, 30-dayand the respective post-harvest treatments] are significantly different.

anal treated control fruits had significantly higher SOD activity from

(p < 0.05) values are designated by different letters. Means having the superscript Aare significantly different from the respective treatment sets on day 2. Means withincolumns followed by different superscripts [within treatments; a – pre-harvest/airtreatments, b – within post-harvest treatments (hexanal, MCP and combination – 15and 30 day) and c – between pre-harvest/air treatment values for 15-days, 30-dayand the respective post-harvest treatments] are significantly different.

2 orticulturae 125 (2010) 239–247

pthscttiaosat

3nptdaassPdA1ohTcit

Table 8Specific activity of ascorbate peroxidase (nmol/min/�g protein) in sweet cherriessubjected to pre- and post-harvest treatments. Sweet cherries were stored for 2, 15and 30 days in air at 4 ◦C and 90–95% relative humidity.

Treatments Ascorbate Peroxidase Activity

Pre-harvest Post-harvest 2 Day 15 Day 30 Day

Control Air 3.9 ± 0.4 A1.8 ± 0.1 A0.9 ± 0.11% EFF Air 4.4 ± 0.6 A1.8 ± 0.2 A1.3 ± 0.12% EFF Air 4.5 ± 0.4 A1.5 ± 0.3 A1.4 ± 0.1

Control Hexanal A1.8 ± 0.2 A1.1 ± 0.31% EFF Hexanal A1.1 ± 0.4 A1.7 ± 0.12% EFF Hexanal A1.1 ± 0.3 A1.2 ± 0.1

Control MCP A1.3 ± 0.2 A1.9 ± 0.1c

1% EFF MCP A1.1 ± 0.1 A1.9 ± 0.12% EFF MCP A1.7 ± 0.2 A2.0 ± 0.2

Control Hexanal + MCP A1.6 ± 0.3 2.1 ± 0.1c

1% EFF Hexanal + MCP A1.7 ± 0.2 A2.1 ± 0.22% EFF Hexanal + MCP A2.4 ± 0.2 A2.7 ± 0.4

Data are the mean ± standard error of three replicates. Statistically significant(p < 0.05) values are designated by different letters. Means having the superscript Aare significantly different from the respective treatment sets on day 2. Means within

FfH

44 M. Sharma et al. / Scientia H

revented the decline in SOD activity that was observed in con-rol and EFF-treated cherries. After 15 days, MCP-treated cherriesad nearly twice the level of SOD activity as compared to the air-tored fruits. Interestingly, SOD activity increased in MCP-treatedherries and reached nearly 5-fold higher levels as compared tohe air-stored fruits on day 30. Cherries subjected to post-harvestreatment with hexanal and 1-MCP together showed a remarkablencrease in SOD activity on day 30 of storage. Even though there wasslight decline in SOD activity in hexanal and 1-MCP-treated fruitsn day 15 from the post-harvest air treated fruits, the SOD activityhowed nearly a 9-fold increase from the respective post-harvestir treated fruits during 30 days of storage. This almost appearedo be an additive effect of hexanal and 1-MCP.

.3.2.2. Changes in ascorbate peroxidase (APX) activities. There wereo significant differences in the initial activity levels of APX (2 dayost-harvest) between control and EFF-treated cherries. In addi-ion, the APX activities in control and EFF treatments declineduring further storage (15 and 30 days) (Table 8). Post-harvest hex-nal treatment did not appear to affect the activities of APX. APXctivities declined in hexanal treated sweet cherries after 15 days oftorage. However, during further storage for 15 days, APX activitylightly increased in post-harvest hexanal treated sprayed fruits.ost-harvest treatment with 1-MCP enhanced APX activity after 30ays of storage compared to air exposed fruits. A slightly elevatedPX activity level was observed in cherries exposed to hexanal and-MCP together after 30 days of storage. Post-harvest treatmentf hexanal and 1-MCP together in control fruits had significantly

igher APX activity than the post-harvest air exposed control fruits.he EFF treatments did not affect the APX activity substantially. Byomparison to ascorbate peroxidase, total guiacol peroxidase activ-ty was relatively low and did not show any significant change withreatment or during storage (data not shown).

ig. 1. Changes in Bing cherry fruit color as a result of pre-harvest application of the Enhormulation. The fruits were sprayed twice, 14 days and 7 days before harvest. Unsprayedex; fruits sprayed with antioxidants – panel labelled AOX and fruits sprayed with EFF –

columns followed by different superscripts [within treatments; a – pre-harvest/airtreatments, b – within post-harvest treatments (hexanal, MCP and combination – 15and 30 days) and c – between pre-harvest/air treatment values for 15-day, 30-dayand the respective post-harvest treatments] are significantly different.

3.4. Effect of different compositions on the appearance of fruits

During the 2007 season, the effects of various components in the

EFF formulation that contribute to an increase in quality character-istics were evaluated. Since hexanal is the primary phospholipaseD inhibitor ingredient in the formulation, it was presumed thata hexanal formulation will be as effective as the total EFF eventhough the antioxidants in the formulation may contribute to the

anced Freshness Formulation (EFF), the hexanal formulation, and the antioxidantcontrol – panel labelled C; fruits sprayed with hexanal formulation – panel labelledpanel labelled EFF.

orticu

qaaotfilpEiTttvftf

4

ppassphUts

ioott(aEmrsifipbliioe

ttsnstdffi

M. Sharma et al. / Scientia H

uality enhancement to a certain degree. The effect of pre-harvestpplication of the hexanal formulation, antioxidant formulationnd the total EFF is shown in Fig. 1. At the optimal harvest timef unsprayed controls, the fruits were dark purple characteristico the Bings (panel labeled C). At the same time of harvest, theruits subjected to hexanal formulation treatment showed a delayn purple coloration, and being more reddish in appearance (panelabeled hex). The fruits subjected to the EFF treatment had a moreronounced red hue than the hexanal treated fruits (panel labeledFF). The fruits sprayed with the antioxidant formulation were sim-lar in appearance to the unsprayed control (panel labeled AOX).he fruits subjected to the hexanal and EFF treatments attainedhe purple coloration within a week during cold storage. As well,he EFF sprayed fruits became purple at the time of a second har-est delayed by 1 week after the optimal harvest. The hexanalormulation treated fruits showed enhanced firmness similar tohat observed in EFF-treated fruits as compared to the unsprayedruits (data not shown).

. Discussion

Sweet cherry is a highly perishable crop. Because of its shortroduction season and high demand, there is great interest inreservation of shelf life and quality in cherry fruits. Cold temper-ture storage of cherries provides only a minimal extension of thehelf life. As well, the quality of fruits decline during prolongedtorage. In the present study, we have evaluated the effect of are-harvest treatment using a hexanal formulation, and two post-arvest treatments using 1-MCP (Smartfresh, AgroFresh Inc., PA,SA) and hexanal vapour (AgroFresh Inc., PA, USA) for their effec-

iveness in enhancing and preserving the shelf life and quality inweet cherries.

The development of quality characteristics in ripening fruitsnvolves several catabolic reactions that include the breakdownf cell wall and pectin, degradation of the membrane, breakdownf stored carbohydrates into sugars, a reduction in acidity andhe biosynthesis of color and volatile components, contributing tohe overall improvement in the organoleptic quality of the fruitsPaliyath and Murr, 2006). Several of these biochemical changesre interrelated and share common, overlapping biochemical steps.thylene-induced gene expression is a key event in the enhance-ent in activities of several enzymes involved in the catabolic

eactions (e.g. cell wall degradation, aromatic volatile biosynthe-is). Thus, blocking ethylene perception with the use of 1-MCPs an approved technology for extending the shelf life of severalruit crops (Lurie and Paliyath, 2008). As well, metabolite channel-ng from degradative biochemical pathways into quality enhancingathways can result in enhanced quality characteristics. Thus, bylocking ethylene action by 1-MCP, and by reducing membrane

ipid degradation with the application of the phospholipase Dnhibitor hexanal, metabolites that are normally used for replenish-ng the degraded phospholipids can be channeled into the synthesisf quality enhancing components (Sharma et al., 2008), potentiallynhancing shelf life and quality.

One of the significant findings of this study is the consis-ently high red color observed in fruits sprayed with 2% EFF. Athe time of harvest, fruits from the EFF (2% EFF) sprayed treeshowed a bright red color by contrast to a purple red color asoticed in the control fruits. However, during storage the EFFprayed fruits also developed the purple red color characteris-

ic of ‘Bing’ cherries. Such a change in coloration may indicate aelay in the ripening process in EFF sprayed sweet cherries as theruits naturally show the transition from red to purple in controlruits. Hexanal and antioxidant compounds such as ascorbic acidn the formulation may also have helped in fruit color retention

lturae 125 (2010) 239–247 245

(Paliyath et al., 2003; Paliyath and Murr, 2007). The post-harvestexposure of cherries to hexanal did not result in any significantenhancement in color suggesting that hexanal is effective onlyas a pre-harvest spray in sweet cherries. The decrease in chromavalue (C) during storage is primarily a reflection of the intensi-fying purple color, as there was no decrease in the levels of anyof the anthocyanins that contribute to the red color of cherries.EFF (2%) treated cherries showed a lower hue angle suggesting anupregulation of carotenoid biosynthesis. An increase in the expres-sion of carotenoid synthesizing genes was noticed in the presenceof ethylene in apricots (Cunningham and Gantt, 1998). 1-MCP-treated cherry tomatoes also had a lower proportion of carotenoids(Opiyo and Ying, 2005) indicating the influence of ethylene incarotenoid biosynthesis. The color value parameters decreased dur-ing post-harvest storage of cherries as observed earlier (Remòn etal., 2004).

Pre-harvest application of EFF did not result in increased firm-ness in sweet cherries. Post-harvest treatments with hexanal,1-MCP, and hexanal + 1-MCP increased firmness in treated cherriesas compared to the control fruits after 15 days of storage. 1-MCP andhexanal treated cherries showed the highest firmness after 15 daysof storage. A linear correlation between turgor pressure and firm-ness in sweet cherries has been observed previously (Lustig, 1987;Barrett and Gonzalez, 1994; Wang and Vestrheim, 2002; Martinez-Romero et al., 2006). Since increased firmness was predominantlynoticeable in MCP and hexanal treated fruits, this is likely to bea physiological effect rather than a physical alteration caused byturgor changes. Therefore, the observed changes may be due toincreased fruit cell wall biosynthesis and membrane preservation.

Pre- and post-harvest treatments with hexanal and 1-MCP didnot result in any major changes on the levels of soluble solids incherries as observed earlier (Wang and Vestrheim, 2002). Ethylenehad no effect on soluble solids levels in non-climacteric fruits (El-Kereamy et al., 2003).

The amount of total phenolics determined in sweet cherries wasin the range of 0. 6 mg/g fresh weight to 0.8 mg/g fresh weight at thetime of harvest. Previous studies have reported similar (Gao andMazza, 1995) as well as higher (Goncalves et al., 2004a,b) valuesfor total phenolics in sweet cherries. A slight increase in pheno-lics level was noticed in EFF-treated cherries during storage. Thisincrease is consistent with numerous previous studies in sweetcherry (Heinonen et al., 1998), strawberry and raspberry (Kalt etal., 1999) and apples (Rocha and Morais, 2005).

The derivatives of hydroxycinnamic acids, neochlorogenic acid,p-coumarylquinic acid and feruloyl glucose were the major pheno-lic acids in sweet cherry. These phenolic compounds contribute tothe color of sweet cherries through co-pigmentation with antho-cyanins (Chaovanalikit and Wrolstad, 2004). Anthocyanin analysisof sweet cherries showed cyanidin-3-rutinoside as a major antho-cyanin component in sweet cherries, which is in agreement withprevious reports on sweet cherry anthocyanins (Mozetic et al.,2006; Chaovanalikit and Wrolstad, 2004; Rocha and Morais, 2005).In previous findings, cyanidin-3-glucoside also has been reported asa major anthocyanin, but in the present study cyanidin-3-glucosidewas found to be a minor anthocyanin, which may be due to thedifference in cultural and environmental conditions. Besides this,peonidin-3-rutinoside, pelargonidin-3-rutinoside and petunidin-3,5-diglucoside were also identified as minor anthocyanins. Thecontinued biosynthesis of anthocyanins during fruit storage hasalso been observed earlier (Kalt et al., 1999; Gao and Mazza, 1995;Goncalves et al., 2004a,b).

An efficient antioxidant system is essential for the maintenanceof cellular compartmentalization and preservation of nutritionalcomponents and antioxidants (Kalt et al., 1999; Shaham et al.,2003; Hayat et al., 2005; Ahn et al., 2007). Being the first enzymeof the antioxidant system, SOD plays an important role in scav-

2 orticu

easpFeffmoipncNSrtfaiei2

rwesi2saecwReiai

A

ABoP

R

A

B

B

B

C

C

D

E

46 M. Sharma et al. / Scientia H

nging of active oxygen species. SOD activity declined in controlnd EFF-treated fruits during storage for 30 days. By contrast,weet cherries exposed to hexanal, 1-MCP as well as hexanallus 1-MCP showed significantly higher SOD activities in fruits.ruits exposed to hexanal and 1-MCP together showed the high-st increase in SOD activity. A higher SOD activity in 1-MCP-treatedruits has been reported previously (Goncalves et al., 2004b). There-ore, enhancement in the antioxidant capacity in response to 1-MCP

ay provide a beneficial role in the preservation of fruits. More-ver, 1-MCP treatment may enhance the antioxidant potentialn fruits resulting in a high reactive oxygen species scavengingotential. A higher incidence of core browning in pears has beenoticed due to the accumulation of ROS resulting in membrane de-ompartmentalization during post-harvest storage (Fu et al., 2007).evertheless, 1-MCP treatment in pears enhanced the activities ofOD, POX, APX and CAT antioxidant enzymes, and subsequentlyeduced the incidence of core browning. It is interesting to notehat hexanal treatment also enhanced the SOD activity in cherryruits. In addition, the activities of downstream enzymes such asscorbate peroxidase are critical for removal of hydrogen perox-de generated by SOD activity. At 30 day of storage, sweet cherriesxposed to hexanal and 1-MCP showed elevated level of APX activ-ty, which is in agreement with previous studies (Goncalves et al.,004b).

By contrast to the 1-MCP technology which is widely usedecently, the phospholipase D inhibition technology has not beenidely adapted. The effect of phospholipase D inhibition on

nhancing the shelf life and quality of fruits was known for a con-iderable period of time (Paliyath and Subramanian, 2008). Thenhibition of phospholipase D by hexanal (Paliyath et al., 1999,003; Paliyath and Murr, 2007) is a novel approach because of itsimplicity and the natural occurrence of hexanal in plants. Hex-nal application to apple fruit slices reduced microbial growth andnhanced storage life (Lanciotti et al., 1999). Hexanal vapour appli-ation to plum fruits reduced the expression of PR10 proteins asell as the expression of phospholipase D (El-Kereamy et al., 2009).ecent results also suggest that hexanal treatment affects the genexpression profiles in tomato fruits in a similar manner to thatnduced by 1-MCP (Tiwari and Paliyath, unpublished). Thus, hex-nal by itself, appears to enhance post-harvest quality and shelf lifen fruits.

cknowledgement

We gratefully acknowledge the financial assistance fromgroFresh Inc., PA, USA, the Tender Fruit Producers’ Marketingoard and the Natural Sciences and Engineering Research Councilf Canada. We would like to thank Valsala Kallidumbil and Ramanyaliyath for helping with the experiments.

eferences

hn, T., Paliyath, G., Murr, D.P., 2007. Antioxidant enzyme activities in apple varietiesand resistance to superficial scald development. Food Res. Int. 40, 1012–1019.

arrett, D.M., Gonzalez, C., 1994. Activity of softening enzymes during cherry mat-uration. J. Food Sci. 59, 574–577.

lankenship, S.M., Dole, J.M., 2003. 1-Methylcyclopropene: a review. PostharvestBiol. Technol. 28, 1–25.

radford, M.M., 1976. A rapid and sensitive method for the quantitation of micro-gram quantity of protein utilizing the principle of protein dye binding. Anal.Biochem. 72, 248–254.

haovanalikit, A., Wrolstad, R.E., 2004. Total anthocyanins and total phenolics offresh and processed cherries and their antioxidant properties. J. Food Sci. 69,FCT67–FCT72.

unningham, F.X., Gantt, E., 1998. Genes and enzymes of carotenoid biosynthesis inplants. Annu. Rev. Plant Physiol. Plant Mol. Biol. 49, 557–583.

e Ell, J.R., Khanizadeh, S., Saad, F., Ferree, D.C., 2001. Factors affecting apple fruitfirmness—a review. J. Am. Pomol. Soc. 55, 8–27.

l-Kereamy, A., Chervin, C., Roustan, J.P., Cheynier, V., Souquet, J.M., Moutounet,M., Raynal, J., Ford, C., Latcheı, A., Pech, J.C., Bouzayen, M., 2003. Exogenous

lturae 125 (2010) 239–247

ethylene stimulates the long-term expression of genes related to anthocyaninbiosynthesis in grape berries. Physiol. Plant. 119, 175–182.

El-Kereamy, A., Jayasankar, S., Taheri, A., Errampalli, D., Paliyath, G., 2009. Expressionanalysis of a plum pathogenesis related 10 (PR 10) protein during brown rotinfection. Plant Cell Rep. 28, 95–102.

Fu, L., Cao, J., Li, Q., Lin, L., Jiang, W., 2007. Effect of 1-methylcyclopropene on fruitquality and physiological disorders in Yali pear (Pyrus bretschneideri Rehd.) dur-ing storage. Food Sci. Technol. Int. 13, 49–54.

Gao, L., Mazza, G., 1995. Characterization, quantitation, and distribution of antho-cyanins and colorless phenolics in sweet cherries. J. Agric. Food Chem. 43,343–346.

Goncalves, B., Landbo, A.K., Knudse, D., Silva, A.P., Moutinho-Pereira, J., Rosa, E.,Meyer, A.S., 2004a. Effect of ripeness and postharvest storage on the phenolicprofiles of cherries (Prunus avium L.). J. Agric. Food Chem. 52, 523–530.

Goncalves, B., Landbo, A.K., Let, M., Silva, A.P., Rosa, E., Meyer, A.S., 2004b. Storageaffects the phenolic profiles and antioxidant activities of cherries (Prunus aviumL.) on human low-density lipoproteins. J. Sci. Food Agric. 84, 1013–1020.

Gong, Y.P., Fan, X.T., Mattheis, J.P., 2002. Responses of ‘Bing’ and ‘Rainier’ sweetcherries to ethylene and 1-methylcyclopropene. J. Am. Soc. Hort. Sci. 127,831–835.

Hayat, I., Masud, T., Rathore, H., 2005. Effect of Coating and Wrapping materials onthe shelf life of apple (Malus domestica cv.Borkh). Int. J. Food Saf. 5, 24–34.

Heinonen, I.M., Meyer, A.S., Frankel, E.N., 1998. Antioxidant activity of berry phe-nolics on human low-density lipoprotein and liposome oxidation. J. Agric. FoodChem. 46, 4107–4112.

Jacob, J.K., Hakimuddin, F., Fisher, H., Paliyath, G., 2008. Antioxidant and antiprolif-erative activities of polyphenols in novel high polyphenol grape lines. Food Res.Int. 41, 419–428.

Kalt, W., Forney, C.F., Martin, A., Prior, R.L., 1999. Antioxidant capacity, vitamin C,phenolics, and anthocyanins after fresh storage of small fruits. J. Agric. FoodChem. 47, 4638–4644.

Kang, S.Y., Seeram, N.P., Nair, M.G., Bourquin, L.D., 2003. Tart cherry anthocyaninsinhibit tumor development in APCMin mice and reduce proliferation of humancolon cancer cells. Cancer Lett. 194, 13–19.

Ku, V.V.V., Wills, R.B.H., Ben-Yehoshua, S., 1999. 1-Methylcyclopropene can differen-tially affect the postharvest life of strawberries exposed to ethylene. HortScience34, 119–120.

Lanciotti, R., Corbo, M.R., Gardini, F., Sinigaglia, S., Guerzoni, M.E., 1999. Effect ofhexanal on the shelf life of fresh apple slices. J. Agric. Food Chem. 47, 4769–4776.

Lurie, S., Paliyath, G., 2008. Enhancing postharvest shelf life and quality in horticul-tural commodities using 1-MCP technology. In: Paliyath, G., Murr, D.P., Handa,A., Lurie, S. (Eds.), Post-harvest Biology and Technology of Fruits, Vegetables andFlowers. Wiley-Blackwell, Iowa, pp. 139–161.

Lustig, I., 1987. An improved firmness tester for juicy fruit. HortScience 22, 653–655.Macheix, J., Fleuriet, A., Billot, J., 1990. Fruit Phenolics. CRC Press, Boca Raton, FL.Madamanchi, N.R., Donahue, J.L., Cramer, C.L., Alscher, R.G., Pedersen, K., 1994. Dif-

ferential response of Cu, Zn superoxide dismutases in two pea cultivars duringa short-term exposure to sulfur dioxide. Plant Mol. Biol. 26, 95–103.

Martinez-Romero, D., Alburquerque, N., Valverde, J.M., Guillen, F., Castillo, S., Valero,D., Serrano, M., 2006. Postharvest sweet cherry quality and safety maintenanceby Aloe vera treatment: a new edible coating. Postharvest Biol. Technol. 39,93–100.

Mozetic, B., Simcic, M., Trebse, P., 2006. Anthocyanins and hydroxycinnamic acidsof Lambert Compact cherries (Prunus avium L.) after cold storage and 1-methylcyclopropene treatment. Food Chem. 97, 302–309.

Opiyo, A.M., Ying, T.J., 2005. The effects of 1-methylcyclopropene treatment on theshelf life and quality of cherry tomato (Lycopersicon esculentum var. cerasiforme)fruit. Int. J. Food Sci. Technol. 40, 665–673.

Paliyath, G., Droillard, M.J., 1992. The mechanisms of membrane deterioration anddisassembly during senescence. Plant Physiol. Biochem. 30, 789–812.

Paliyath, G., Pinhero, R.G., Yada, R.Y., Murr, D.P., 1999. Effect of processing conditionson phospholipase D activity of corn kernel subcellular fractions. J. Agric. FoodChem. 47, 2579–2588.

Paliyath, G., Murr, D.P., 2007. Compositions for the preservation of fruits and veg-etables. US patent # 7,198,811.

Paliyath, G., Murr, D.P., 2006. Biochemistry of fruits. In: Hui, Y.H. (Ed.), Food Bio-chemistry and Food Processing. Blackwell Publishing, Iowa, pp. 487–514.

Paliyath, G., Subramanian, J., 2008. Phospholipase D inhibition technology forenhancing shelf life and quality. In: Paliyath, G., Murr, D.P., Handa, A., Lurie,S. (Eds.), Post-harvest Biology and Technology of Fruits, Vegetables and Flowers.Wiley-Blackwell, IA, pp. 240–245.

Paliyath, G., Murr, D.P., Yada, R.Y., Pinhero, R.G., 2003. Inhibition of phospholipaseD. US patent # 6,514,914.

Palou, L., Crisosto, C.H., Garner, D., Basinal, L.M., 2003. Effect of continuous exposureto exogenous ethylene during cold storage on postharvest decay developmentand quality attributes of stone fruits and table grapes. Postharvest Biol. Technol.27, 243–254.

Rao, M.V., Paliyath, G., Ormrod, D.P., 1996. Ultraviolet-B- and ozone-induced bio-chemical changes in antioxidant enzymes of Arabidopsis thaliana. Plant Physiol.

110, 125–136.

Remòn, S., Ferrer, A., Lòpez-Buesa, P., Oria, R., 2004. Atmosphere composition effectson Burlat cherry color during cold storage. J. Sci. Food Agric. 84, 140–146.

Rocha, A.M.C.N., Morais, A.M.M.B., 2005. Polyphenoloxidase activity of minimallyprocessed ‘Jonagored’ apples (Malus domestica). J. Food Process. Preserv. 29,8–19.

orticu

S

S

M. Sharma et al. / Scientia H

calbert, A., Manach, C., Morand, C., Remesy, C., Jimenez, L., 2005. Dietarypolyphenols and the prevention of diseases. Crit. Rev. Food Sci. Nutr. 45,287–306.

haham, Z., Lers, A., Lurie, S., 2003. Effect of heat or 1-methylcyclopropene on antiox-idative enzyme activities and antioxidants in apples in relation to superficialscald development. J. Am. Soc. Hort. Sci. 128, 761–766.

lturae 125 (2010) 239–247 247

Sharma, M., Sitbon, C., Paliyath, G., Subramanian, J., 2008. Changes in nutritionalquality of fruits and vegetables during storage. In: Paliyath, G., Murr, D.P., Handa,A., Lurie, S. (Eds.), Post-harvest Biology and Technology of Fruits, Vegetables andFlowers. Wiley-Blackwell, IA, pp. 443–456.

Wang, L., Vestrheim, S., 2002. Controlled atmosphere storage of sweet cherries(Prunus avium L.). Acta Agric. Scand. B-Soil Plant Sci. 52, 136–142.